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YOSHIOKA Tomohisa
Research Center for Membrane and Film Technology
Professor

Researcher basic information

■ Research news
  • 25 Dec. 2019, Development of ultrathin durable membrane for efficient oil and water separation
    Link to Kobe Univ. HP
■ Research Keyword
  • Chemical engineering in general
  • 化学工学一般
■ Research Areas
  • Manufacturing technology (mechanical, electrical/electronic, chemical engineering) / Transfer phenomena and unit operations

Research activity information

■ Award
  • 13 Nov. 2020 日本膜学会 膜シンポジウム2020, 優秀学生ポスター学生賞, 界面活性剤の分離精製における新規NF膜及びプロセス開発
    角南俊輔, 新谷卓司, 中川敬三, 佐々木雄史, 松山秀人
    Japan society

  • 26 Sep. 2020 The 18th Asian Pacific Confederation of Chemical Engineering Congress (APCChE 2019), Encouragement Award of Separation Process Division, Effect of composite membrane structure on performance of graphene oxide/metal oxide nanosheets composite membranes
    Misato KUNIMATSU, Keizo NAKAGAWA, Tomohisa YOSHIOKA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    Japan society

  • 26 Sep. 2020 The 18th Asian Pacific Confederation of Chemical Engineering Congress (APCChE 2019), Encouragement Award of Separation Process Division, Development of novel organic solvent resistant RO membrane
    Ayane HIROSUE, Takuji SHINTANI, Keizo NAKAGAWA, Yuji SASAKI, Susumu HASEGAWA, Tomohisa YOSHIOKA, Hideto MATSUYAMA
    Japan society

  • 26 Sep. 2020 The 18th Asian Pacific Confederation of Chemical Engineering Congress (APCChE 2019), Excellent Student Award, Development of novel organic solvent resistant RO membrane
    Ayane HIROSUE, Takuji SHINTANI, Keizo NAKAGAWA, Yuji SASAKI, Susumu HASEGAWA, Tomohisa YOSHIOKA, Hideto MATSUYAMA
    Japan society

  • 25 May 2020 分離技術会 年会2019, 学生賞, ニオブ酸化物ナノシート/酸化グラフェン複合型積層膜の作製とナノろ過特性の評価
    國松美里, 中川敬三, 吉岡朋久, 新谷卓司, 神尾英治, 松山秀人
    Japan society

  • 25 May 2020 分離技術会 年会2019, 奨励賞, ミクロ孔充填相透過法を用いた多孔性セラミック膜の細孔径分布評価
    小川祐生, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    Japan society

  • 10 May 2020 日本膜学会 第42年会, 優秀学生ポスター学生賞, 有機キレート配位子を鋳型にしたチタニア－ジルコニア複合ナノろ過膜の有機溶剤透過・分画特性評価
    家迫遼介, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    Japan society

  • Mar. 2019 日本海水学会若手会第10回学生研究発表会, 優秀賞, 電気透析排水から2価陽イオンと2価陰イオンを選択分離する新規ナノ濾過膜の開発
    濵田 慎之介, SHINTANI TAKUJI, 赤松 憲樹, NAKAGAWA KEIZO, SASAKI YUJI, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    Japan society

  • Oct. 2018 日本海水学会 第5回海水・生活・化学連携シンポジウム, 優秀ポスター賞, 正浸透膜法の駆動溶液に用いる温度応答性イオン液体の会合挙動に関する検討
    栗栖 宏樹, TAKAHASHI TOMOKI, YOSHIOKA TOMOHISA, MATSUYAMA HIDETO
    Japan society

  • Sep. 2018 化学工学会秋季大会第50年会, 学生賞, 膜-透過分子間相互作用を考慮した多孔性セラミック膜の細孔構造評価
    小川 祐生, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    Japan society

  • May 2018 分離技術会 年会2018, 学生賞, Pt内包シリカナノチューブを利用した触媒膜の作製
    岩崎 太幹, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    Japan society

  • Mar. 2018 化学工学会学生発表会第20回, 優秀賞, グリセロール⾻格を有する温度応答性⾼分⼦の開発と正浸透プロセスへの応⽤
    小川 祐生, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    Japan society

  • Mar. 2018 日本海水学会若手会第9回学生研究発表会, 奨励賞(鳴門塩業(株)賞), 電気透析排水から2価陽イオンと2価陰イオンを選択分離する新規ナノ濾過膜の開発
    濵田 慎之介, SHINTANI TAKUJI, 赤松 憲樹, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, HASEGAWA Susumu, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    Japan society

  • Nov. 2017 膜シンポジウム2017, 学生賞, 浸透圧補助低圧逆浸透法を用いた高濃縮膜プロセスの検討
    東郷範弘, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KAMIO EIJI, KISHIMOTO MICHIMASA, MATSUYAMA HIDETO
    International society

  • Sep. 2017 化学工学会第49回秋季大会, 分離プロセス部会ポスターセッションポスター賞, ニオブ酸ナノシート積層型分離膜のシートサイズが及ぼす膜性能への影響
    世良 友宏, NAKAGAWA KEIZO, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    Japan society

  • 2016 化学工学会第82回年会, 優秀学生賞 化学工学会第82回年会, ポリアミド活性層の表面改質が及ぼす正浸透膜法による糖液濃縮およびバイオエタノール生産への影響
    張 一涵, 渋谷 真史, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KISHIMOTO MICHIMASA, KAMIO EIJI, MATSUYAMA HIDETO
    Japan society

  • 2016 日本海水学会若手会第8回学生研究発表会, 日本海水学会若手会 第8回学生研究発表会 優秀賞, 浸透圧補助低圧逆浸透法による海水濃縮技術に関する基礎的検討
    東郷 範弘, 田中 裕大, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, KAMIO EIJI, SHINTANI TAKUJI, KISHIMOTO MICHIMASA, YOSHIOKA TOMOHISA, MATSUYAMA HIDETO
    Japan society

  • 2016 第19回化学工学会学生発表会(豊中大会), 第19回化学工学会学生発表会 優秀賞, 有機キレートを用いた多孔性TiO2-ZrO2複合膜の作製と構造評価
    貞 佑樹, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    Japan society

■ Paper
  • Ralph Rolly Gonzales, Keizo Nakagawa, Susumu Hasegawa, Kazuo Kumagai, Atsushi Matsuoka, Yasunao Okamoto, Zhan Li, Zhaohuan Mai, Tomohisa Yoshioka, Tomoyuki Hori, Hideto Matsuyama
    Elsevier BV, Jan. 2025, Separation and Purification Technology, 352, 128159 - 128159
    Scientific journal

  • Takaya Fujiki, Megumi Kaji, Yuuya Tamamizu, Ryuuki Yasunari, Keizo Nakagawa, Tooru Kitagawa, Yasunao Okamoto, Atsushi Matsuoka, Eiji Kamio, Hideto Matsuyama, Tomohisa Yoshioka
    Elsevier BV, Jun. 2024, Separation and Purification Technology, 337, 126249 - 126249
    Scientific journal

  • Shengnan He, Eiji Kamio, Atsushi Matsuoka, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    Elsevier BV, Mar. 2024, Journal of Membrane Science, 695, 122482 - 122482
    Scientific journal

  • Yasuyuki Miyoshi, Yoshitomo Nakata, Tooru Kitagawa, Hideto Matsuyama, Tomohisa Yoshioka, Keizo Nakagawa
    American Chemical Society (ACS), Feb. 2024, Industrial & Engineering Chemistry Research
    Scientific journal

  • Ryota Kumokita, Takahiro Bamba, Hisashi Yasueda, Ayato Tsukida, Keizo Nakagawa, Tooru Kitagawa, Tomohisa Yoshioka, Hideto Matsuyama, Yasuhito Yamamoto, Satoshi Maruyama, Takahiro Hayashi, Akihiko Kondo, Tomohisa Hasunuma
    Elsevier BV, Feb. 2024, Bioresource Technology, 393, 130144 - 130144
    Scientific journal

  • Atsushi Matsuoka, Masayuki Fukushima, Eiji Kamio, Tomohisa Yoshioka, Keizo Nakagawa, Yasunao Okamoto, Hideto Matsuyama
    American Chemical Society (ACS), Nov. 2023, Industrial & Engineering Chemistry Research, 62(46) (46), 19845 - 19854
    Scientific journal

  • Ralph Rolly Gonzales, Keizo Nakagawa, Kazuo Kumagai, Susumu Hasegawa, Atsushi Matsuoka, Zhan Li, Zhaohuan Mai, Tomohisa Yoshioka, Tomoyuki Hori, Hideto Matsuyama
    Elsevier BV, Nov. 2023, Water Research, 246, 120716 - 120716
    Scientific journal

  • Zhan Li, Pengfei Zhang, Yu-Hsuan Chiao, Kecheng Guan, Ralph Rolly Gonzales, Ping Xu, Zhaohuan Mai, Guorong Xu, Mengyang Hu, Tooru Kitagawa, Tomohisa Yoshioka, Hideto Matsuyama
    Elsevier BV, Nov. 2023, Desalination, 566, 116936 - 116936
    Scientific journal

  • Shengnan He, Eiji Kamio, Jinhui Zhang, Atsushi Matsuoka, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    Elsevier BV, Nov. 2023, Journal of Membrane Science, 685, 121912 - 121912
    Scientific journal

  • Keizo Nakagawa, Takumi Ueno, Zheng Wang, Tomohisa Yoshioka, Jiri Kulhavy, Keita Taniya, Atsushi Matsuoka, Eiji Kamio, Shik Chi Edman Tsang, Hideto Matsuyama
    Elsevier BV, Oct. 2023, Chemical Engineering Journal, 474, 145671 - 145671
    Scientific journal

  • Etsuko Tachi, Tomohisa Yoshioka, Takaya Fujiki, Ryuuki Yasunari, Keizo Nakagawa, Tooru Kitagawa, Yasunao Okamoto, Atsushi Matsuoka, Eiji Kamio, Hideto Matsuyama
    Elsevier BV, Oct. 2023, Separation and Purification Technology, 322, 124091 - 124091
    Scientific journal

  • Yusuke Yoshiwaka, Tooru Kitagawa, Takuji Shintani, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    Elsevier BV, Sep. 2023, Separation and Purification Technology, 320, 124150 - 124150
    Scientific journal

  • Shinya Nishiyama, Naomichi Kimura, Tomoya Hirai, Keizo Nakagawa, Tomohisa Yoshioka
    American Chemical Society (ACS), Aug. 2023, Industrial & Engineering Chemistry Research
    Scientific journal

  • Atsushi Matsuoka, Airi Motoyama, Eiji Kamio, Tomohisa Yoshioka, Keizo Nakagawa, Hideto Matsuyama
    Elsevier BV, Aug. 2023, Journal of Molecular Liquids, 383, 122145 - 122145
    Scientific journal

  • Shunsuke Kitamura, Tomohisa Yoshioka, Keizo Nakagawa, Tooru Kitagawa, Yasunao Okamoto, Atsushi Matsuoka, Eiji Kamio, Hideto Matsuyama
    Elsevier BV, Jun. 2023, Separation and Purification Technology, 315, 123576 - 123576
    Scientific journal

  • Zheng Wang, Keizo Nakagawa, Kecheng Guan, Qiangqiang Song, Siyu Zhou, Shunsuke Tanaka, Yasunao Okamoto, Atsushi Matsuoka, Eiji Kamio, Guangchao Li, Molly Meng-Jung Li, Tomohisa Yoshioka, Hideto Matsuyama
    Laminar membranes comprising graphene oxide (GO) and metal-organic framework (MOF) nanosheets benefit from the regular in-plane pores of MOF nanosheets and thus can support rapid water transport. However, the restacking and agglomeration of MOF nanosheets during typical vacuum filtration disturb the stacking of GO sheets, thus deteriorating the membrane selectivity. Therefore, to fabricate highly permeable MOF nanosheets/reduced GO (rGO) membranes, a two-step method is applied. First, using a facile solvothermal method, ZnO nanoparticles are introduced into the rGO laminate to stabilize and enlarge the interlayer spacing. Subsequently, the ZnO/rGO membrane is immersed in a solution of tetrakis(4-carboxyphenyl)porphyrin (H2 TCPP) to realize in situ transformation of ZnO into Zn-TCPP in the confined interlayer space of rGO. By optimizing the transformation time and mass loading of ZnO, the obtained Zn-TCPP/rGO laminar membrane exhibits preferential orientation of Zn-TCPP, which reduces the pathway tortuosity for small molecules. As a result, the composite membrane achieves a high water permeance of 19.0 L m-2  h-1  bar-1 and high anionic dye rejection (>99% for methyl blue).
    Apr. 2023, Small (Weinheim an der Bergstrasse, Germany), e2300672, English, International magazine
    Scientific journal

  • Tomoki Watanabe, Keizo Nakagawa, Ralph Rolly Gonzales, Tooru Kitagawa, Atsushi Matsuoka, Eiji Kamio, Tomohisa Yoshioka, Hideto Matsuyama
    Wiley, Mar. 2023, Journal of Applied Polymer Science, 140(22) (22)
    Scientific journal

  • Zhan Li, Pengfei Zhang, Kecheng Guan, Ralph Rolly Gonzales, Toru Ishigami, Ming Xue, Tomohisa Yoshioka, Hideto Matsuyama
    Ammonia is a toxic and hazardous substance, as well as a valuable chemical. The gaseous ammonia are soluble in water, rendering some industrial wastewater contains high concentration of ammonia. These wastewater can be a direct source for the production of commercially concentrated ammonia solution via sweep gas membrane distillation (SGMD). Taking advantage of vapor-liquid equilibrium of ammonia-water binary system, ammonia can be recovered from these wastewater, and concentrated to several times higher concentration under optimized conditions. In this work, we have demonstrated the ammonia recovery by SGMD process, and comprehensively investigated the effect of different operation conditions on the SGMD performance.
    Mar. 2023, Process Safety and Environmental Protection, 171, 555 - 560
    Scientific journal

  • Kecheng Guan, Yanan Guo, Zhan Li, Yuandong Jia, Qin Shen, Keizo Nakagawa, Tomohisa Yoshioka, Gongping Liu, Wanqin Jin, Hideto Matsuyama
    Nanochannels in laminated graphene oxide nanosheets featuring confined mass transport have attracted interest in multiple research fields. The use of nanochannels for reverse osmosis is a prospect for developing next-generation synthetic water-treatment membranes. The robustness of nanochannels under high-pressure conditions is vital for effectively separating water and ions with sub-nanometer precision. Although several strategies have been developed to address this issue, the inconsistent response of nanochannels to external conditions used in membrane processes has rarely been investigated. In this study, we develop a robust interlayer channel by balancing the associated chemistry and confinement stability to exclude salt solutes. We build a series of membrane nanochannels with similar physical dimensions but different channel functionalities and reveal their divergent deformation behaviors under different conditions. The deformation constraint effectively endows the nanochannel with rapid deformation recovery and excellent ion exclusion performance under variable pressure conditions. This study can help understand the deformation behavior of two-dimensional nanochannels in pressure-driven membrane processes and develop strategies for the corresponding deformation constraints regarding the pore wall and interior.
    Feb. 2023, Nature communications, 14(1) (1), 1016 - 1016, English, International magazine
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Titik Istirokhatun, Yuqing Lin, Ken Kinooka, Qin Shen, Pengfei Zhang, Yuandong Jia, Atsushi Matsuoka, Kazuo Kumagai, Tomohisa Yoshioka, Hideto Matsuyama
    Elsevier BV, Feb. 2023, Water Research, 230, 119567 - 119567
    Scientific journal

  • Ralph Rolly Gonzales, Keizo Nakagawa, Susumu Hasegawa, Atsushi Matsuoka, Kazuo Kumagai, Tomohisa Yoshioka, Hideto Matsuyama
    Elsevier BV, Jan. 2023, Journal of Membrane Science, 665, 121122 - 121122
    Scientific journal

  • Shota Takao, Saeid Rajabzadeh, Masahide Shibata, Chihiro Otsubo, Toyozo Hamada, Noriaki Kato, Keizo Nakagawa, Tooru Kitagawa, Hideto Matsuyama, Tomohisa Yoshioka
    For the first time, we have successfully fabricated microfiltration (MF) hollow fiber membranes by the thermally induced phase separation (TIPS) and non-solvent induced phase separation (NIPS) methods using cellulose acetate benzoate (CBzOH), which is a cellulose derivative with considerable chemical resistance. To obtain an appropriate CBzOH TIPS membrane, a comprehensive solvent screening was performed to choose the appropriate solvent to obtain a membrane with a porous structure. In parallel, the CBzOH membrane was prepared by the NIPS method to compare and evaluate the effect of membrane structure using the same polymer material. Prepared CBzOH membrane by TIPS method showed high porosity, pore size around 100 nm or larger and high pure water permeability (PWP) with slightly low rection performance compared to that by NIPS. On the contrary, CBzOH membranes prepared with the NIPS method showed three times lower PWP with higher rejection. The chemical resistance of the prepared CBzOH membranes was compared with that of cellulose triacetate (CTA) hollow fiber membrane, which is a typical cellulose derivative as a control membrane, using a 2000 ppm sodium hypochlorite (NaClO) solution. CBzOH membranes prepared with TIPS and NIPS methods showed considerable resistance against the NaClO solution regardless of the membrane structure, porosity and pore size. On the other hand, when the CTA membrane, as the control membrane, was subjected to the NaClO solution, membrane mechanical strength sharply decreased over the exposure time to NaClO. It is interesting that although the CBzOH TIPS membrane showed three times higher pure water permeability than other membranes with slightly lower rejection and considerably higher NaClO resistance, the mechanical strength of this membrane is more than two times higher than other membranes. While CBzOH samples showed no change in chemical structure and contact angle, CTA showed considerable change in chemical structure and a sharp decrease in contact angle after treatment with NaClO. Thus, CBzOH TIPS hollow fiber membrane is noticeably interesting considering membrane performance in terms of filtration performance, mechanical strength and chemical resistance on the cost of slightly losing rejection performance.
    MDPI, Dec. 2022, MEMBRANES, 12(12) (12), English
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Yu Fujimura, Takahiro Kawakatsu, Masayuki Morimoto, Hitoshi Asakawa, Keizo Nakagawa, Tomohisa Yoshioka
    Elsevier BV, Dec. 2022, Journal of Molecular Liquids, 367, 120441 - 120441
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Jinhui Zhang, Eiji Kamio, Atsushi Matsuoka, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    Elsevier BV, Dec. 2022, Journal of Membrane Science, 663, 121032 - 121032
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Yu-Hsuan Chiao, Keizo Nakagawa, Mayu Matsuba, Masanao Okamoto, Takuji Shintani, Yuji Sasaki, Tomohisa Yoshioka, Eiji Kamio, S. Ranil Wickramasinghe, Hideto Matsuyama
    American Chemical Society (ACS), Oct. 2022, Industrial & Engineering Chemistry Research, 61(41) (41), 15345 - 15354
    Scientific journal

  • Atsushi Matsuoka, Shihomi Nishimori, Tomoki Takahashi, Eiji Kamio, Tomohisa Yoshioka, Keizo Nakagawa, Hideto Matsuyama
    Elsevier BV, Oct. 2022, Desalination, 540, 115991 - 115991
    Scientific journal

  • Zhan Li, Saikat Das, Taishu Sekine, Haruna Mabuchi, Ryo Kaneko, Jin Sakai, Tsukasa Irie, Eiji Kamio, Tomohisa Yoshioka, Jinquan Suo, Qianrong Fang, Tokuhisa Kawawaki, Hideto Matsuyama, Yuichi Negishi
    American Chemical Society (ACS), Sep. 2022, ACS Applied Nano Materials
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Shota Takao, Saeid Rajabzadeh, Chihiro Otsubo, Toyozo Hamada, Noriaki Kato, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Tomohisa Yoshioka
    For the first time, self-standing microfiltration (MF) hollow fiber membranes were prepared from cellulose triacetate (CTA) via the thermally induced phase separation (TIPS) method. The resultant membranes were compared with counterparts prepared from cellulose diacetate (CDA) and cellulose acetate propionate (CAP). Extensive solvent screening by considering the Hansen solubility parameters of the polymer and solvent, the polymer's solubility at high temperature, solidification of the polymer solution at low temperature, viscosity, and processability of the polymeric solution, is the most challenging issue for cellulose membrane preparation. Different phase separation mechanisms were identified for CTA, CDA, and CAP polymer solutions prepared using the screened solvents for membrane preparation. CTA solutions in binary organic solvents possessed the appropriate properties for membrane preparation via liquid-liquid phase separation, followed by a solid-liquid phase separation (polymer crystallization) mechanism. For the prepared CTA hollow fiber membranes, the maximum stress was 3-S times higher than those of the CDA and CAP membranes. The temperature gap between the cloud point and crystallization onset in the polymer solution plays a crucial role in membrane formation. All of the CTA, CDA, and CAP membranes had a very porous bulk structure with a pore size of similar to 100 nm or larger, as well as pores several hundred nanometers in size at the inner surface. Using an air gap distance of 0 mm, the appropriate organic solvents mixed in an optimized ratio, and a solvent for cellulose derivatives as the quench bath media, it was possible to obtain a CTA MF hollow fiber membrane with high pure water permeance and notably high rejection of 100 nm silica nanopartides. It is expected that these membranes can play a great role in pharmaceutical separation.
    AMER CHEMICAL SOC, Sep. 2022, ACS Omega, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Qiangqiang Song, Yuqing Lin, Takafumi Ueda, Qin Shen, Kueir Rarn Lee, Tomohisa Yoshioka, Hideto Matsuyama
    Interlayered thin-film composite (TFC) membranes have a great potential for enhancing salt separation in wastewater reclamation, because of the highly permeable and selective properties. However, mechanistic insights regarding the structural features of the surface nanofilms and their corresponding interlayers, which lead to enhanced separation efficiency, remain poorly understood. Herein, we report a zwitterionic copolymer 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-amino-ethyl methacrylate hydrochloride (AEMA) (P[MPC-co-AEMA]) interlayered TFC membrane that exhibits an ultrahigh water permeance of 20.4 L m−2 h−1 bar−1 (almost three folds higher water permeance than that of the pristine PA membrane), together with a simultaneously enhanced rejection of inorganic salts (96.8% against Na2SO4). Detailed mechanistic investigations revealed that the promoted membrane separation property was mainly explained as the enriched amine monomer diffusion-driven instability induced by the P[MPC-co-AEMA] interlayer. This triggers membrane sealing and inhibits its growth, leading to the formation of an ultrathin PA nanofilm with a thickness of 12 nm, a ridge-shaped surface structure with enhanced specific surface area, and enhanced crosslinking. The fundamental mechanism revealed in this study lays a solid foundation for the engineering of the high-performance TFC membrane, which is appealing for the energy-efficient water remediation industry.
    Sep. 2022, Journal of Membrane Science, 657
    Scientific journal

  • Ryosuke Iesako, Tomohisa Yoshioka, Keizo Nakagawa, Takuji Shintani, Atsushi Matsuoka, Eiji Kamio, Hideto Matsuyama
    Elsevier BV, Sep. 2022, Separation and Purification Technology, 297, 121458 - 121458
    Scientific journal

  • Zhan Li, Pengfei Zhang, Kecheng Guan, Tomohisa Yoshioka, Hideto Matsuyama
    Vacuum membrane distillation (VMD) has received considerable attention from both academia and industry. During VMD, the liquid-vapor interface is supported by a porous hydrophobic membrane to prevent wetting of the membrane pores and allow only vapor to pass through. Therefore, it is advantageous for the production of high-purity water by desalination, and improving the membrane performance has attracted significant attention. In this work, we present a facile method of modifying polyvinylidene difluoride (PVDF) membranes with a fluorine-containing ionic liquid (BPPF6) to improve the membrane hydrophobicity and antiwetting and antifouling properties. The dynamic water contact angle of the membrane increased from 124.5 ± 0.3° to 136.7 ± 0.1°, and the VMD water flux increased by 14.2% for treating 3.5 wt% NaCl aqueous solution at 45 °C.
    Aug. 2022, Desalination, 536
    Scientific journal

  • Seiji Imoto, Keizo Nakagawa, Chechia Hu, Tomohisa Yoshioka, Takuji Shintani, Atsushi Matsuoka, Eiji Kamio, Takashi Tachikawa, Shik Chi Edman Tsang, Hideto Matsuyama
    Elsevier BV, Aug. 2022, Chemical Engineering Journal, 442, 136254 - 136254
    Scientific journal

  • Ralph Rolly Gonzales, Takuji Shintani, Shunsuke Sunami, Yuji Sasaki, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    One process involved in biorefinery for generation of value-added products is fermentation. After fermentation, the downstream bioproduct purification process is conventionally performed by organic solvent extraction, which is environmentally-hazardous and costly. Membrane-based separation is a cost-efficient and environmentally-benign method for bioproduct separation and purification. In this study, a thin film composite (TFC) nanofiltration (NF) membrane was prepared and the pore size and charge of the polyamide layer were controlled by introducing iminodiacetic acid (IDA), a charged monoamine monomer, with piperazine (PIP) during interfacial polymerization (IP). The newly-developed NF membrane was found to have a molecular weight cut-off (MWCO) of 500 to 1350 Da, allowing the permeation of the fermentation product, while rejecting other higher molecular weight compounds. IDA addition in the aqueous amine solution during IP effectively engineered the MWCO values and pore sizes of TFC NF membranes for specific applications, such as separation of fermentation bioproducts. This study successfully showed that IDA reduced the diffusivity of PIP during IP, which negatively affected the polyamide formation and membrane performance. The optimal PIP:IDA concentration ratio was determined by MWCO and effective pore diameter for effective bioproduct separation and purification, which could not be performed by the current commercially-available NF membranes.
    Jul. 2022, Journal of Applied Polymer Science, 139(26) (26)
    Scientific journal

  • Takahito Nakao, Shohei Goda, Yuki Miura, Masahiro Yasukawa, Miharu Ishibashi, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Tomohisa Yoshioka
    Osmotically assisted reverse osmosis (OARO) has been recently proposed for concentrating high-salinity brines. The long-term performance stability of the membrane is essential for OARO, considering the long-term commercial operation. In this study, we developed hollow fiber membranes for OARO operation made of cellulose triacetate, and elucidated the relationship between the membrane structure and resistance to compaction against long-term operation under high pressure at 7.0 MPa. The mechanical properties and the performance of membranes operated under reverse osmosis (RO) conditions were very well correlated with the long-term performances and dimensional stabilities of membranes operated under OARO conditions. Raman spectroscopy revealed the asymmetricity difference of the membranes before and after long-term operation. Finally, operation for more than 700 h under OARO conditions was performed using commercial-sized membrane modules, and this result was as expected based on results from laboratory-scale membrane modules. The membrane developed for higher compaction resistance retained 95% water permeance even after operation for 700 h. This study clearly showed a relationship between the resistance to compaction and the membrane structure, both of which are important for practical OARO operation.
    Jul. 2022, Journal of Membrane Science, 653
    Scientific journal

  • Kecheng Guan, Kai Ushio, Keizo Nakagawa, Takuji Shintani, Tomohisa Yoshioka, Atsushi Matsuoka, Eiji Kamio, Wanqin Jin, Hideto Matsuyama
    Elsevier BV, Jul. 2022, Journal of Membrane Science, 120861 - 120861
    Scientific journal

  • Mohammadreza Shirzadi, Zhan Li, Tomohisa Yoshioka, Hideto Matsuyama, Tomonori Fukasawa, Kunihiro Fukui, Toru Ishigami
    We developed a computational fluid dynamics (CFD) model that can describe the transport phenomena and performance in a vacuum membrane distillation (VMD) module for ammonia-water separation. This model is based on a multicomponent approach that considers the flow, heat transfer, and mass transfer for the liquid phase on the feed side and gaseous phases on the permeate side. The permeation fluxes across the membrane were modeled theoretically based on Knudsen diffusion and Poiseuille flow. A calibration parameter was introduced to compensate for the error in the permeation flux caused by the uncertainty in the membrane properties necessary for the calculation of the permeation flux. To validate the model, we conducted a laboratory-scale VMD experiment for ammonia-water separation. The predicted permeation rate, ammonia recovery ratio, and ammonia concentration on the permeate side were in good agreement with the experimental results at different inlet flow rates on the feed side. The relative errors of the CFD model in the prediction of ammonia permeation rate, recovery ratio, and ammonia concentration on the permeate side were 8, 1, and 5%, respectively. A parametric study of the effect of the inlet ammonia concentration on the feed side and vacuum pressure applied to the permeate side was conducted to understand the flow and mass transfer characteristics, and the relationship with the module performance was discussed. Sensitivity analysis of the process parameters to the module performance was performed using the simulation results obtained from the parametric study.
    Jun. 2022, Industrial and Engineering Chemistry Research, 61(21) (21), 7381 - 7396
    Scientific journal

  • Jinhui Zhang, Eiji Kamio, Atsushi Matsuoka, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    American Chemical Society (ACS), Apr. 2022, Industrial & Engineering Chemistry Research, 61(13) (13), 4648 - 4658
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Qin Shen, Yuqing Lin, Takafumi Ueda, Pengfei Zhang, Yuandong Jia, Titik Istirokhatun, Qiangqiang Song, Kecheng Guan, Tomohisa Yoshioka, Hideto Matsuyama
    The development of ultrathin polyamide (PA) nanofilms with desirable water permeance and high selectivity has been recognized as crucial for energy-efficient desalination of salty water and wastewater reclamation. In this study, an ultrathin PA reverse osmosis membrane (∼25 nm) was fabricated via polydopamine (PDA) interlayer-mediated interfacial polymerization onto a polyethersulfone (PES) substrate. The ultrathin PDA interlayer was soldered in situ onto PES substrates by precisely controlling the ammonia-initiated self-assembly process. Furthermore, the PDA interlayer conferred a high-density uptake toward aqueous amine monomers and served as a quasi-molecular-scale regulator that mediated their diffusion into the organic phase to polymerize with the acyl chloride of 1, 3, 5-benzenetricarbonyl trichloride (TMC). The synergistic effects triggered self-sealing and inhibited membrane growth, promoting the formation of an ultrathin and defect-free PA nanofilm with a hierarchical nanostripe surface. The newly developed membranes exhibited a desirable water permeance of up to 1.44 L m−2 h−1·bar−1, almost triple that of the pristine PA membrane (0.44 L m−2 h−1·bar−1), and a simultaneously enhanced rejection ratio of 99.2% toward NaCl. This work sheds light on strategies to develop ultrathin PA-based membranes with high water permselectivity for environmental- and energy-relevant applications.
    Mar. 2022, Journal of Membrane Science, 646
    Scientific journal

  • Yu Fujimura, Takahiro Kawakatsu, Keizo Nakagawa, Takuji Shintani, Tomohisa Yoshioka
    Elsevier {BV}, Feb. 2022, Journal of Molecular Liquids, 347, 118366 - 118366, English
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • K.I. Ikrari, H. Hasbullah, W.N.W. Salleh, K. Nakagawa, T. Yoshioka
    Elsevier BV, 2022, Materials Today: Proceedings, 65, 3101 - 3108, English
    Scientific journal

  • Wataru Kushida, Ralph Rolly Gonzales, Takuji Shintani, Atsushi Matsuoka, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    Organic solvent reverse osmosis (OSRO) is currently considered as an energy-efficient membrane technology for separation of organic liquid mixtures.
    Royal Society of Chemistry (RSC), 2022, Journal of Materials Chemistry A
    Scientific journal

  • Keizo Nakagawa, Misato Kunimatsu, Kengo Yasui, Tomohisa Yoshioka, Takuji Shintani, Eiji Kamio, Kuo Lun Tung, Shik Chi Edman Tsang, Hideto Matsuyama
    Organic solvent nanofiltration (OSN) is an energy-efficient alternative to distillation and evaporation for the separation of mixtures containing organic liquids. Laminar membranes using nanosheets as building blocks have great potential for OSN; however, a swelling of the interlayer spacing causes a severe decrease in the separation performance. Here, we present laminar HNb3O8-based composite membranes fabricated by vacuum filtration on an anodic aluminum oxide support for OSN applications. The laminar HNb3O8 membranes and composite (graphene oxide (GO) and HNb3O8) membranes were found to possess stable structures in various alcohols without severe swelling. As a result, the HNb3O8-based membranes showed higher dye rejections than the GO membrane. Among the HNb3O8-based membranes, the layered GO/HNb3O8 membrane had superior dye rejections in methanol (89.6% for Evans blue, 73.4% for acid red 265, and 43.4% for methyl orange) compared with the GO membranes. Alcohol permeation tests implied that the molecular diameter, rather than the solvent viscosity, was the dominant factor in the superior performance of the layered GO/HNb3O8 membrane. Molecular dynamics simulations suggest a stable GO/HNb3O8 interlayer ranging from around 1.165 to 1.333 nm, and a dense heterolayer formation at the interface between the HNb3O8 and GO layers. This heterolayer formation performs important roles in alcohol permeation and separation of organic dyes. Furthermore, the layered GO/HNb3O8 membrane showed stable permeation of a model photoresist waste liquid for 6 weeks and an excellent rejection of the photoresist waste, over 91%. We propose that laminar HNb3O8-based membranes have great potential for OSN applications.
    Dec. 2021, Journal of Membrane Science, 640
    Scientific journal

  • Takashi Ohkame, Kazushi Minegishi, Hideki Sugihara, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Tomohisa Yoshioka
    We report a new type of alkaline-stable hollow-fiber reverse osmosis (RO) membrane with an outside-in configuration that was established via adsorption of positively charged poly(vinyl alcohol) copolymers containing a small amount of quaternary ammonium moieties. Anionic sulfonated poly(arylene ether sulfone nitrile) hollow-fiber membranes were utilized as a substrate upon which the cationic copolymer layer was self-organized via electrostatic interaction. While the adsorption of the low-charge copolymer on the membrane support proceeded in a Layer-by-Layer (LbL) fashion, it was found that the adsorbed amount by one immersion step was enough to form a defect-free separation layer with a thickness of around 20 nm after cross-linking of vinyl alcohol units with glutaraldehyde. The resultant hollow-fiber membrane showed excellent desalination performances (NaCl rejection of 98.3% at 5 bar and 1500 mg/L), which is comparable with commercial low-pressure polyamide RO membranes, as well as good alkaline resistance. The separation performance could be restored by repeating the LbL treatment after alkaline degradation. Such features of LbL membranes may contribute to extending RO membrane lifetimes.
    MDPI, Dec. 2021, MEMBRANES, 11(12) (12), English
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Keizo Nakagawa, Shintaro Araya, Kai Ushio, Misato Kunimatsu, Tomohisa Yoshioka, Takuji Shintani, Eiji Kamio, Kuo Lun Tung, Hideto Matsuyama
    Two-dimensional (2D) laminar membranes are attracting much attention in organic solvent nanofiltration owing to the promising permeation and selective performance derived from their 2D ultrathin separation layer. However, owing to easy swelling (enlargement of interlayer spacing), controlling the interlayer spacing in organic solvents and stable solvent permeation are major issues for their application to organic solvent systems. In this study, laminar GO membranes were fabricated on a porous polyketone (PK) support membrane using triethanolamine (TEOA) as crosslinker (GO-TEOA/PK). The interlayer spacing (d) between GO sheets was characterized by X-ray diffraction. The TEOA crosslinker effectively suppressed swelling of the GO laminar structure. For GO-TEOA/PK, the variation in d corresponded well with the affinity between TEOA and each solvent, Ra(TEOA–solvent), as estimated using the Hansen solubility parameters. Furthermore, common linear correlation between the permeance of alcohols and the parameter combining affinity, viscosity, and equivalent molar diameter was clearly observed. Therefore, the affinity between crosslinker and solvent was an important factor in controlling interlayer spacing and solvent permeation in the laminar GO membranes containing crosslinker.
    Dec. 2021, Separation and Purification Technology, 276
    Scientific journal

  • Mahmoud Rahmati, Saeid Rajabzadeh, Amira Abdelrasoul, Yuki Kawabata, Tomohisa Yoshioka, Hideto Matsuyama, Toraj Mohammadi
    Recently, nano-filtration membranes are made by the reaction between a reactive functional group on the surface of a tight ultrafiltration membrane and a charged branched polymer. This reaction makes the selective layer of the nanofiltration membrane, which plays an essential role in membrane performance. A molecular dynamics simulation with a reactive force field was used to investigate the reaction of carboxylated polyethersulfone as the functional group of the ultrafiltration membrane with polyethyleneimine. Experimental elucidation of the reaction between the PEI amine and carboxyl groups is challenging, and an MD simulation was thus employed. Furthermore, the simulation results show that the PEI and carboxylated polyethersulfone polymers react with each other in a temperature-dependent manner. While no reaction occurs at 298 K, carboxylated polyethersulfone and PEI begin to react when the temperature is increased from 298 to 323 K. Furthermore, a reversible reaction was observed with a subsequent increase in temperature to 353 K.
    Nov. 2021, Journal of Applied Polymer Science, 138(44) (44)
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Eiji Kamio, Hiroki Kurisu, Tomoki Takahashi, Atsushi Matsuoka, Tomohisa Yoshioka, Keizo Nakagawa, Yuchen Sun, Hideto Matsuyama
    In this work, several types of ionic liquid (IL)-based thermosensitive draw solutions (DSs) were prepared for application in the forward osmosis (FO) process. The temperature dependence of the osmotic pressure of IL-based DS was investigated to examine the advantages of high-temperature membrane operation for regeneration and water recovery from the DS lean phase after liquid–liquid phase separation of DS with a lower critical solution temperature (LCST). From surface tension and dynamic light scattering measurements, it was found that the association of IL molecules and aggregation of IL associates occurred in hot water, which led to a decrease in the osmotic pressure of the IL-DS at elevated temperatures. The DS regeneration and water recovery using an RO membrane were examined using tetrabutylammonium 2,4,6-trimethylbenzenesulfonate with the largest temperature dependence on osmotic pressure. At elevated temperatures, the water flux and DS concentration in the concentrated solution increased effectively. The investigation demonstrated that high-temperature membrane operation is effective for the regeneration of LCST-type thermosensitive DS and water recovery.
    Nov. 2021, Separation and Purification Technology, 275
    Scientific journal

  • Qiangqiang Song, Yuqing Lin, Takafumi Ueda, Titik Istirokhatun, Qin Shen, Kecheng Guan, Tomohisa Yoshioka, Hideto Matsuyama
    In this study, a highly perm-selective thin-film composite (TFC) nanofilm was successfully developed via silicification interlayer-mediated interfacial polymerization. The silicification interlayer, fabricated in situ, significantly improved the surface hydrophilicity of the polysulfone (PSf) substrate and facilitated the high-density uptake of amine monomers. The interlayer also served as a quasi-molecular-scale regulator that decelerated the diffusion of amine monomers into the organic phase to polymerize with the acyl chloride of 1,3,5-benzenetricarbonyl trichloride (TMC). The synergistic effects triggered self-sealing and inhibited the membrane growth, which promoted the formation of ultrathin polyamide (PA) nanofilms (approx. 13 nm) with enhanced crosslinking properties. The best-performing PA_SiO2/PSf membrane exhibited a high water permeance of 14.5 L m(-2) h(-1) bar(-1), which was approximately three times the permeance of the pristine PA membrane (4.8 L m(-2) h(-1) bar(-1)). Furthermore, the membrane exhibited a high rejection capability toward divalent salts (98.7% against Na2SO4) and mono/divalent ion selectivity of 60.9. Hence, the newly developed PA_SiO2/PSf membrane exhibits competitive separation properties compared to the state-of-the-art desalination membranes. The technique is applicable to the majority of conventional interfacial polymerizations, which highlights its use in the development of high-performance membranes for water remediation.
    ROYAL SOC CHEMISTRY, Nov. 2021, JOURNAL OF MATERIALS CHEMISTRY A, 9(46) (46), 26159 - 26171, English
    Scientific journal

  • Yuki Kawabata, Ralph Rolly Gonzales, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Yu Fujimura, Takahiro Kawakatsu, Tomohisa Yoshioka
    Reverse osmosis (RO) is a widely used energy-efficient separation technology for water treatment. Polyamide (PA) membranes are the conventional choice for this process. Fouling is a serious problem for RO separation. This issue leads to significant decreases in the water permeability of PA membranes, and it has yet to be fully elucidated. In particular, the fouling behavior of a nonionic substance on the negatively charged surface of a PA membrane in an aqueous environment has not been previously studied. In this work, the mechanisms of nonionic substances such as polyoxyethylene octyl ether (PE5) and maltose (Mal) were investigated using molecular dynamics (MD) simulations. In a PA membrane in which the carboxyl group was not dissociated, the hydrophobic portion of the membrane was exposed due to the localization of water molecules around the carboxyl groups in the PA membrane. This caused hydrophobic interaction with the hydrophobic groups of PE5. In the case of an amine-modified PA membrane containing no carboxyl groups, water was not localized around the functional group, and the water orientation of the polyamide surface was also low. Due to this membrane property, the presence of stabilized water around PE5 reduced the number of hydrophobic interactions. In similar manner, a PA membrane with a slightly dissociated carboxyl group was hydrophilic, which reduced the PE5 adsorption. The presence of many dissociated carboxyl groups, however, enhanced the adsorption of PE5 due to the increase in interactions between the dissociated carboxyl groups and the hydrophilic groups of PE5. Therefore, PE5 exhibited an amphipathic adsorption wherein both hydrophilic and hydrophobic groups contributed to adsorption onto the PA membrane. Mal, on the other hand, was highly stable in every aqueous environment independent of the state of the functional groups of the PA membrane, and was not easily affected by the properties of the PA membrane.
    Sep. 2021, Physical chemistry chemical physics : PCCP, English, International magazine
    Scientific journal

  • Jinhui Zhang, Eiji Kamio, Masayuki Kinoshita, Atsushi Matsuoka, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    An inorganic/organic micro-double-network (mu-DN) ion gel-based composite membrane with good mechanical properties and high CO2 permeance was developed in this study. The mu-DN ion gel was composed of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C(4)mim][Tf2N]), a cross-linked polymer network, and silica nanoparticle clusters. The mechanical strength of the mu-DN ion gel was optimized to achieve a fracture energy of 636 kJ/m(3). The fabricated composite membrane with an ion gel layer thickness of 4.5 mu m shows a CO2/N-2 permselectivity of 23 and a CO2 permeance of 119 GPU. The gas permeance of the composite membranes was calculated by considering a series of diffusion processes, and the results were in good agreement with the experimental data. The calculation results obtained using the proposed model show high potential of our mu-DN ion gel to achieve much higher CO2 permeance.
    AMER CHEMICAL SOC, Sep. 2021, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 60(34) (34), 12698 - 12708, English
    Scientific journal

  • Jinhui Zhang, Eiji Kamio, Atsushi Matsuoka, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    A micro-double-network (mu-DN) ion gel membrane was fabricated using nonvolatile network precursors comprising a presynthesized cross-linkable polymer as the organic part, silica nanoparticles as the inorganic part, and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C(4)mim][Tf2N]). The mechanical properties of the ion gel were effectively improved through optimizing the molecular weight of the cross-linkable polymer and the organic/inorganic network composition. The mu-DN ion gel membranes exhibited the CO2 permeability of approximately 920 Barrer under atmospheric pressure, which is much higher than those of the classic double-network ion gel membranes fabricated using volatile network precursors (556 Barrer) and the supported ionic liquid membranes (617 Barrer). The membrane also has good pressure resistance and long-term stability. The mu-DN ion gel membrane formed by nonvolatile network precursors shows good mechanical properties and high CO2 separation performance, which make it a good candidate base material for developing high-permeance thin ion gel membranes.
    AMER CHEMICAL SOC, Sep. 2021, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 60(34) (34), 12640 - 12649, English
    Scientific journal

  • Yuqing Lin, Qin Shen, Yuki Kawabata, Jumpei Segawa, Xingzhong Cao, Kecheng Guan, Titik Istirokhatun, Tomohisa Yoshioka, Hideto Matsuyama
    Recent innovations highlight the great potential of zero-dimensional materials of graphene quantum dots (GQDs) as attractive candidates for fabricating advanced nanofiltration membranes. In this study, a novel class of thinfilm composite (TFC) nanofiltration membranes derived from assembled GQDs with amino/sulfonic modification (GQDs_N/S) as building blocks directly, is developed to achieve highly selective water transport for highperformance nanofiltration via interfacial polymerization. Based on the transport behavior, the intrinsically hydrophilic sulfonic groups are introduced to endow the membrane with stronger internal polarity and more accessible sites for easier water molecules infiltration, while engineering the nanochannels by covalently immobilizing GQDs between the terminal amino groups and trimesoyl chloride. Furthermore, an enhanced interparticle space with enlarged free volumes between GQDs is obtained for rapidly transporting water molecules inside the membrane, owing to the intercalation of sulfonic groups acting as spacers to break up the tightly stacking structure of GQDs. The resultant GQDs_N/S TFC membrane exhibits superior separation properties with high water permeance of 9.82 L m-2h- 1 bar-1 and 97.4% rejection against Na2SO4, giving rise to more than 2fold higher water permeability without obviously sacrificing the membrane selectivity, and revealing an outperformed separation property when compared to state-of-the-art nanofiltration membranes. Simultaneously, the sulfonic and amino sites firmly anchored on GQDs with custom-tailored functionality further enables the GQDs_N/S TFC membrane to perform an outstanding antifouling property and durability over the long-term operation condition. The proposed approach opens new pathways to fabricate highly permeable-selective nanofiltration membranes.
    ELSEVIER SCIENCE SA, Sep. 2021, CHEMICAL ENGINEERING JOURNAL, 420, English
    Scientific journal

  • Yuqing Lin, Xuesong Yao, Qin Shen, Takafumi Ueda, Yuki Kawabata, Jumpei Segawa, Kecheng Guan, Titik Istirokhatun, Qiangqiang Song, Tomohisa Yoshioka, Hideto Matsuyama
    A highly permselective nanofiltration membrane was engineered via zwitterionic copolymer assembly regulated interfacial polymerization (IP). The copolymer was molecularly synthesized using single-step free-radical polymerization between 2-methacryloyloxyethyl phosphorylcholine (MPC) and 2-aminoethyl methacrylate hydrochloride (AEMA) (P[MPC-co-AEMA]). The dynamic network of P[MPC-co-AEMA] served as a regulator to precisely control the kinetics of the reaction by decelerating the transport of piperazine toward the water/hexane interface, forming a polyamide (PA) membrane with ultralow thickness of 70 nm, compared to that of the pristine PA (230 nm). Concomitantly, manipulating the phosphate moieties of P[MPC-co-AEMA] integrated into the PA matrix enabled the formation of ridge-shaped nanofilms with loose internal architecture exhibiting enhanced inner-pore interconnectivity. The resultant P[MPC-co-AEMA]-incorporated PA membrane exhibited a high water permeance of 15.7 L·m-2·h-1·bar-1 (more than 3-fold higher than that of the pristine PA [4.4 L·m-2·h-1·bar-1]), high divalent salt rejection of 98.3%, and competitive mono-/divalent ion selectivity of 52.9 among the state-of-the-art desalination membranes.
    Aug. 2021, Nano Letters, 21(15) (15), 6525 - 6532
    Scientific journal

  • Eiji Kamio, Hiroki Kurisu, Tomoki Takahashi, Atsushi Matsuoka, Tomohisa Yoshioka, Keizo Nakagawa, Hideto Matsuyama
    Forward osmosis (FO) membrane process is expected to realize energy-saving seawater desalination. To this end, energy-saving water recovery from a draw solution (DS) and effective DS regeneration are essential. Recently, thermo-responsive DSs have been developed to realize energy-saving water recovery and DS regeneration. We previously reported that high-temperature reverse osmosis (RO) treatment was effective in recovering water from a thermo-responsive ionic liquid (IL)-based DS. In this study, to confirm the advantages of the high-temperature RO operation, thermo-sensitive IL-based DS was treated by an RO membrane at temperatures higher than the lower critical solution temperature (LCST) of the DS. Tetrabutylammonium 2,4,6-trimethylbenznenesulfonate ([N4444 ][TMBS]) with an LCST of 58◦C was used as the DS. The high-temperature RO treatment was conducted at 60◦C above the LCST using the [N4444 ][TMBS]-based DS-lean phase after phase separation. Because the [N4444 ][TMBS]-based DS has a significantly temperature-dependent osmotic pressure, the DS-lean phase can be concentrated to an osmotic pressure higher than that of seawater at room temperature (20◦C). In addition, water can be effectively recovered from the DS-lean phase until the DS concentration increased to 40 wt%, and the final DS concentration reached 70 wt%. From the results, the advantages of RO treatment of the thermo-responsive DS at temperatures higher than the LCST were confirmed.
    Aug. 2021, Membranes, 11(8) (8)
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Takahito Nakao, Mayumi Akashi, Miharu Ishibashi, Miyuki Yao, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Tomohisa Yoshioka
    Elsevier BV, Aug. 2021, Journal of Membrane Science, 631, 119337 - 119337
    Scientific journal

  • Takashi Ohkame, Masafumi Shibuya, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Tomohisa Yoshioka
    Elsevier BV, Aug. 2021, Journal of Membrane Science, 631, 119336 - 119336
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Nawshad Akther, Yuki Kawabata, Sungil Lim, Tomohisa Yoshioka, Sherub Phuntsho, Hideto Matsuyama, Ho Kyong Shon
    We report an ultra-low loading of graphene oxide quantum dots (GQDs) into the polyamide (PA) layer of an outer-selective hollow fiber (OSHF) thin-film composite (TFC) membrane using the vacuum-assisted interfacial polymerization (VAIP) technique to improve the water permeability of OSHF TFC membranes without sacrificing membrane selectivity. Experimental results showed that GQD loading in the PA layer influenced membrane performance. The membrane with a GQD loading of 5 mg L−1 (TFN5) demonstrated an optimal water flux of 30.9 L m−2 h−1 and a specific reverse solute flux (SRSF) of 0.12 g L−1. To investigate the effect of GQDs on the interfacial polymerization (IP) reaction and membrane performance, molecular dynamics (MD) simulation was employed at the water-hexane and water-PA interfaces. The simulation results showed that GQDs decreased the reaction rate during the IP process by reducing the diffusivities of m-phenylenediamine (MPD) and trimesoyl chloride (TMC). Additionally, GQDs reduced water permeability by acting as barriers to water molecules when present at a high concentration near the PA layer surface. At a very high loading, GQDs aggregated at the water-hexane interface and reduced the membrane selectivity by forming non-selective voids at the interface between the PA layer and GQDs. Together with the experimental findings, the MD simulation results delivered a good insight into the GQDs' effect on the TFC membrane's surface and transport properties at both macroscopic and microscopic levels.
    Jul. 2021, Journal of Membrane Science, 630
    Scientific journal

  • Keizo Nakagawa, Misato Kunimatsu, Kengo Yasui, Tomohisa Yoshioka, Takuji Shintani, Tomoki Yasui, Eiji Kamio, Wei-Song Hung, Kueir-Rarn Lee, Shik Chi Edman Tsang, Hideto Matsuyama
    American Chemical Society (ACS), Mar. 2021, ACS Applied Nano Materials
    Scientific journal

  • Yoshioka Tomohisa, Akamatsu Kazuki, Nakagawa Keizou, Takaba Hiromitsu, Araki Sadao, Kamio Eiji, Matsuoka Atsushi, Kai Teruhiko, Kawakatsu Takahiro, Ohshiba Yuhei, Higa Mitsuru, Ishii Katsunori, Nomura, Mikihiro, Saeki Daisuke, Tsuru Toshinori, Moriyama Norihiro, Sakai Motomu
    THE MEMBRANE SOCIETY OF JAPAN, 2021, MEMBRANE, 46(2) (2), 98 - 111, Japanese

  • Hao Chen Wu, Tomohisa Yoshioka, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama
    The use of an Amphotericin B_Ergosterol (AmBEr) channel as an artificial water channel in forward osmosis filtration (FO) was studied via molecular dynamics (MD) simulation. Three channel models were constructed: a common AmBEr channel and two modified C3deOAmB_Ergosterol (C3deOAmBEr) channels with different diameters (12 Å and 18 Å). During FO filtration simulation, the osmotic pressure of salt-water was a driving force for water permeation. We examined the effect of the modified C3deOAmBEr channel on the water transport performance. By tracing the change of the number of water molecules along with simulation time in the saltwater region, the water permeability of the channel models could be calculated. A higher water permeability was observed for a modified C3deOAmBEr channel, and there was no ion permeation during the entire simulation period. The hydrated ions and water molecules were placed into the channel to explore the ion leakage behavior of the channels. The mean squared displacement (MSD) of ions and water molecules was obtained to study the ion leakage performance. The Amphotericin B-based channels showed excellent selectivity of water molecules against ions. The results obtained on an atomistic scale could assist in determining the properties and the optimal filtration applications for Amphotericin B-based channels.
    2021, Membranes, 11(9) (9)
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Takashi Tachibana, Tomohisa Yoshioka, Keizo Nakagawa, Takuji Shintani, Eiji Kamio, Hideto Matsuyama
    Methyl gallate (MG) and ethyl ferulate (EF) with a benzene ring were separately used as aromatic organic chelating ligands (aOCLs) to prepare two versions of TiO2-ZrO2-aOCL composite sols via hydrolysis and polycondensation reactions with titanium(IV) isopropoxide (Ti(OC3H7)4) and zirconium(IV) butoxide (Zr(OC4H9)4). Thermogravimetric and FT-IR analysis of dry gels revealed that aromatic rings were present in the residual organic matter when the gel was fired under nitrogen at 300 °C. In X-ray diffraction (XRD) measurements, the TiO2-ZrO2 composite material prepared using these two aOCLs showed an amorphous structure with no crystalline peaks for TiO2 and ZrO2. In N2 adsorption/desorption measurements at 77 K, the TiO2-ZrO2 samples using the aOCLs as a template appeared porous with a larger specific surface area than TiO2-ZrO2 without aOCL. TiO2-ZrO2-aOCL composite membranes were prepared by coating and firing TiO2-ZrO2-aOCL sol onto a SiO2 intermediate layer using an α-alumina porous tube as a substrate. Compared with the TiO2-ZrO2 membrane, the TiO2-ZrO2-aOCL membranes had higher gas permselectivity. The TiO2-ZrO2-EF membrane showed a He permeance of 2.69 × 10-6 mol m-2 s-1 Pa-1 with permeance ratios of He/N2 = 10.6 and He/CF4 = 163, while the TiO2-ZrO2-MG membrane revealed a bit less He permeance at 8.56 × 10-7 mol m-2 s-1 Pa-1 with greater permeance ratios of He/N2 = 61.7 and He/CF4 = 209 at 200 °C. A microporous TiO2-ZrO2 amorphous structure was obtained by introducing aOCL. The differences in the side chains of each aOCL could possibly account for the differences in the microporous structures of the resultant TiO2-ZrO2-aOCL membranes.
    Dec. 2020, Membranes, 10(12) (12), English, International magazine
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Zhe Yang, Xinyu Zhang, Ming Xie, Hao-Chen Wu, Tomohisa Yoshioka, Daisuke Saeki, Hideto Matsuyama
    We developed a novel amphiphilic copolymer architecture for thin-film composite (TFC) membranes to integrate "resistant" and "release" strategies against membrane fouling. Two materials were sequentially grafted on TFC reverse osmosis membrane surfaces via dual surface-initiated atom transfer radical polymerization (SI-ATRP): zwitterionic polymer, poly [2-(methacryloyloxy)ethyl-dimethyl-(3-sulfopropyl) ammonium hydroxide] (pMED-SAH) with strong hydmphilicity and poly(2,2,2-trifluoroethyl methacrylate) (pTFEMA) with low surface energy. According to MD simulation and theoretical quantification, the p(MEDSAH-b-TFEMA)-grafted membranes (i.e. amphiphilic TFC membranes) possess not only strong hydration, but also lower surface energy, which yield the features of both fouling resistant and fouling release properties. The superiority of possessing multi-defense properties was further confirmed by the long-term, multi-cycle membrane fouling and cleaning filtration. Compared with pristine TFC and hydrophilic TFC membranes, the amphiphilic TFC membranes showed not only less water flux decline during the fouling filtration, but also higher water flux recovery after cleaning by water. Both theoretical and experimental results strongly suggest that the amphiphilic TFC membrane is a novel candidate for improving membrane antifouling properties.
    ELSEVIER, Nov. 2020, JOURNAL OF MEMBRANE SCIENCE, 614, English
    Scientific journal

  • Yuqing Lin, Hao-Chen Wu, Qin Shen, Lei Zhang, Kecheng Guan, Takuji Shintani, Kuo-Lun Tung, Tomohisa Yoshioka, Hideto Matsuyama
    A polyamide (PA) thin-film nanocomposite (TFN) membrane embedded with post-synthetically functionalized metal-organic framework (MOF) nanofillers of imidazole-2-carbaldehyde (ICA) decorated UiO-66-NH2 nano fillers (ICA_d_UiO-66-NH2) was developed using the interfacial polymerization method. The ICA_d_UiO-66-NH2 nanofiller couples a surface water-capturing ICA decoration, facilitating the rapid transport of water molecules owing to the enhanced internal polarity, while achieving an amplified crosslinking between the terminal amine groups of ICA and trimesoyl chloride, enabling the perfect incorporation of MOF nanofillers within the PA matrix. The resultant ICA_d_UiO-66-NH2@PA TFN membrane with elevated separation property performed comparably high water permeance of 9.4 l m(-2) h(-1) bar(-1) (achieving a nearly 2-fold increase from the initial value of the thin-film composite membrane), and a favorable rejection ratio of 97.4% (Na2SO4). Owing to the unique hierarchical surface microstructure embedded with the intrinsically hydrophilic ICA_d_UiO-66-NH2 nanofillers, the newly-developed TFN membrane exhibited superior antifouling properties. Furthermore, the ICA_d_UiO-66-NH2@PA TFN membrane also retained excellent reusability and durability without significant compromise even after long-term salt, and acid/alkali treatments. Overall, this work provides an insight into the embedding of different functionalized nanofillers inside TFN membranes with elevated separation properties.
    ELSEVIER, Nov. 2020, DESALINATION, 493, English
    Scientific journal

  • Keizo Nakagawa, Kiyohito Uchida, Jiang Ling Chuan Wu, Takuji Shintani, Tomohisa Yoshioka, Yuji Sasaki, Li-Feng Fang, Eiji Kamio, Ho Kyong Shon, Hideto Matsuyama
    Elsevier BV, Nov. 2020, Separation and Purification Technology, 251, 117400 - 117400
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Lara Loske, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    In this study, the characteristics of different types of nanosheet membranes were reviewed in order to determine which possessed the optimum propensity for antifouling during water purification. Despite the tremendous amount of attention that nanosheets have received in recent years, their use to render membranes that are resistant to fouling has seldom been investigated. This work is the first to summarize the abilities of nanosheet membranes to alleviate the effect of organic and inorganic foulants during water treatment. In contrast to other publications, single nanosheets, or in combination with other nanomaterials, were considered to be nanostructures. Herein, a broad range of materials beyond graphene-based nanomaterials is discussed. The types of nanohybrid membranes considered in the present work include conventional mixed matrix membranes, stacked membranes, and thin-film nanocomposite membranes. These membranes combine the benefits of both inorganic and organic materials, and their respective drawbacks are addressed herein. The antifouling strategies of nanohybrid membranes were divided into passive and active categories. Nanosheets were employed in order to induce fouling resistance via increased hydrophilicity and photocatalysis. The antifouling properties that are displayed by two-dimensional (2D) nanocomposite membranes also are examined.
    MDPI AG, Oct. 2020, Membranes, 10(10) (10), 295 - 295
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Lara Loske, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama
    In this study, the characteristics of different types of nanosheet membranes were reviewed in order to determine which possessed the optimum propensity for antifouling during water purification. Despite the tremendous amount of attention that nanosheets have received in recent years, their use to render membranes that are resistant to fouling has seldom been investigated. This work is the first to summarize the abilities of nanosheet membranes to alleviate the effect of organic and inorganic foulants during water treatment. In contrast to other publications, single nanosheets, or in combination with other nanomaterials, were considered to be nanostructures. Herein, a broad range of materials beyond graphene-based nanomaterials is discussed. The types of nanohybrid membranes considered in the present work include conventional mixed matrix membranes, stacked membranes, and thin-film nanocomposite membranes. These membranes combine the benefits of both inorganic and organic materials, and their respective drawbacks are addressed herein. The antifouling strategies of nanohybrid membranes were divided into passive and active categories. Nanosheets were employed in order to induce fouling resistance via increased hydrophilicity and photocatalysis. The antifouling properties that are displayed by two-dimensional (2D) nanocomposite membranes also are examined.
    Oct. 2020, Membranes, 10(10) (10), English, International magazine
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Shingo Hikita, Takuji Shintani, Keizo Nakagawa, Hideto Matsuyama, Tomohisa Yoshioka
    An amphiphilic copolymer was used in the fabrication of hydrophilized poly (vinylidene fluoride) (PVDF) membranes. The amphiphilic copolymer was synthesized via the catalytic chain transfer radical polymerization (CCTP) of poly (methyl methacrylate) macromonomer (PMMA-MM), 2-hydroxyethyl methacrylate (HEMA), and 2-methoxyethyl acrylate (MEA). The copolymer, PMMA-co-P (HEMA-co-MEA) with various copolymerization ratios of HEMA and MEA was added to a stock solution containing PVDF, poly (vinylpyrrolidone) (PVP) and N,N-Dimethylacetamide (DMAc) in the preparation of hollow-fiber membranes via the non-solvent induction phase separation (NIPS) method. The resultant membrane had various porous structures and hydrophilicity. The permeability of the resultant membrane tended to be higher when a copolymer with a lower HEMA copolymerization ratio was added. The membrane was prepared using a copolymer with a high composition ratio of HEMA and had a structure that featured a smaller pore diameter and less connectivity in the inner surface, which reduced the water permeability. Amphiphilic copolymers would interfere with the formation of membrane structure. On the other hand, the surface hydrophilicity was better than that of a blank PVDF membrane, which revealed an interesting trade-off between hydrophilicity and water permeability.
    Oct. 2020, Journal of Membrane Science, 612
    Scientific journal

  • Youhei Yabuno, Kota Mihara, Naoki Miyagawa, Kensaku Komatsu, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Tomohisa Yoshioka
    Poly(vinylidene difluoride) (PVDF) hollow fiber membranes were prepared by using high-temperature rapid nonsolvent-induced phase separation (HTR-NIPS). The conditions for fabricating interconnected bicontinuous structures via HTR-NIPS were investigated. We found that (1) the stock solution must not have a gelation temperature and (2) the membrane must be produced at an outer coagulation solution temperature higher than the upper critical solution temperature of the stock solution. A stock solution of PVDF/gamma-butyrolactone/poly (vinylpyrrolidone) that satisfied these conditions was used for successful fabrication of PVDF membranes with a well-developed interconnected bicontinuous structure. The pure water permeances and strengths of these PVDF membranes were higher than those of previously reported PVDF membranes. A polyamide (PA) active layer was prepared on the PVDF hollow fiber membranes via interfacial polymerization to obtain PA-PVDF. Investigation of forward osmosis (FO) in the active layer facing the feed solution showed that the water flux J(w) increased with decreasing thickness of the support layer. Higher water transport was achieved when the tortuosity tau, estimated from the S value, was lower. This suggests that the interconnected bicontinuous structure of the PVDF membrane is a key factor for FO membranes.
    ELSEVIER, Oct. 2020, JOURNAL OF MEMBRANE SCIENCE, 612, English
    Scientific journal

  • Keizo Nakagawa, Norihiro Togo, Ryosuke Takagi, Takuji Shintani, Tomohisa Yoshioka, Eiji Kamio, Hideto Matsuyama
    Elsevier BV, Oct. 2020, Chemical Engineering Research and Design, 162, 117 - 124
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Atsushi Matsuoka, Eiji Kamio, Tomohisa Yoshioka, Keizo Nakagawa, Hideto Matsuyama
    Elsevier BV, Oct. 2020, Separation and Purification Technology, 248, 117018 - 117018
    [Refereed]
    Scientific journal

  • Tong Yang Hsu, Tse Chiang Huang, Jun Hung Chou, Yi Feng Lin, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama, Hui Hsin Tseng, Kuo Lun Tung
    This study presents two 3-D atmospheric plasma spray models, namely, internal and external powder injections, by using the computational fluid dynamics technique to study the status of the melting of a particle and its in-flight velocity during a porous ceramic layer fabrication process. A bulk fluid model, which solves the time-dependent standard k-ϵ model, is used in combination with a Lagrangian to track the trajectories of alumina particles. The results of the fluid-analytical models are compared with experimental measurements, and it is seen that the spray angle increases as the flow rate of the carrier gas increases, which is more significant for an internal than for an external powder injector. Internal powder injection gives a particle a greater in-flight velocity and particle surface temperature because of the location of the powder injector. It is seen that the particle injection velocity and the particle penetration depth vary with the particle size and the flow rate of the carrier gas and that the dispersion for the internal type is more concentrated than that for the external type because of the momentum. The surrounding setup also plays an important role in the process of plasma spraying.
    Aug. 2020, IEEE Transactions on Plasma Science, 48(8) (8), 2759 - 2767
    Scientific journal

  • Qin Shen, Yuqing Lin, Yuki Kawabata, Yuandong Jia, Pengfei Zhang, Nawshad Akther, Kecheng Guan, Tomohisa Yoshioka, Hokyong Shon, Hideto Matsuyama
    In this study, custom-tailored graphene oxide quantum dots (GOQD) were synthesized as functional nanofillers to be embedded into the polyamide (PA) membrane for reverse osmosis (RO) via interfacial polymerization (IP). The heterostructured interface-functionalization of amine/sulfonic decoration on GOQD (N/S-d-GOQD) takes place via the tuning of the molecular design. The embedded N/S-d-GOQD inside the PA matrix contributes to facilitating water molecules quick transport due to the more accessible capturing sites with higher internal polarity, achieving a nearly 3-fold increase in water permeance when compared to the pristine thin-film composite (TFC) membrane. Covalent bonding between the terminal amine groups and the acyl chloride of trimesoyl chloride (TMC) enables the formation of an amplified selective layer, while the sulfonic part assists in maintaining a robust membrane surface negative charge, thus remarkably improving the membrane selectivity toward NaCl. As a result, the newly developed TFN membrane performed remarkably high water permeance up to 5.89 L m(-2) h(-1) bar(-1) without the compromising of its favorable salt (NaCl) rejection ratio of 97.1%, revealing a comparably high separation property when comparing to the state-of-the-art RO membranes, and surpassing the permeability-selectivity trade-off limits. Furthermore, we systematically investigated the GOQDs with different surface decorations but similar configurations (including 3 different nanofillers of pristine GOQD, amine decorated GOQD (N-d-GOQD), and N/S-d-GOQD) to unveil the underlying mechanisms of the swing effects of internal geometry and polarity of the embedded nanofillers on contributing to the uptake, and/or release of aqueous molecules within TFN membranes, providing a fundamental perspective to investigate the impact of embedded nanofillers on the formation of an IP layer and the overall transporting behavior of the RO process.
    AMER CHEMICAL SOC, Aug. 2020, ACS APPLIED MATERIALS & INTERFACES, 12(34) (34), 38662 - 38673, English
    Scientific journal

  • Geng-Sheng Lin, Yu-Cheng Liu, Ramasamy Anbarasan, Keizo Nakagawa, Tomohisa Yoshioka, Hideto Matsuyama, Hui-Hsin Tseng, Kuo-Lun Tung
    Atmospheric plasma spraying (APS) of silicon carbide (SiC) is a challenging task due to the severe decomposition behaviour of the SiC. Previous studies, which utilized APS technique, mixed SiC powder with metals and/or metal oxides to prepare SiC coating. None of them sprayed silica gel-coated SiC and examined the characteristics of the coatings. In this work, silica gel-coated SiC, sodium dodecyl sulfate (SDS) enhanced silica gel-coated SiC, and the combination of alumina (Al2O3) and SiC were prepared and then deposited onto a titanium (Ti) plate by APS. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), adhesion and acid resistance test were performed to analyse the characteristics of modified powders and coatings. We found that compared to Commercial-SiC coatings, all the modified SiC coatings not only increase the coating thickness but also enhance the adhesion force between the coating and substrate; furthermore, the SDS-modified sample exhibits good sulfuric acid (H2SO4) resistance. On the other hand, samples containing Al2O3 showed a significant increase in coating thickness and adhesion force, despite a bit lower acid resistance. In sum, we believe that compared to silica-gel coated samples, Al2O3 contained samples are more suitable for industrial application. (C) 2020 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
    ELSEVIER, May 2020, JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS, 110, 173 - 181, English
    Scientific journal

  • Takuji Shintani, Kazuki Akamatsu, Shinnosuke Hamada, Keizo Nakagawa, Hideto Matsuyama, Tomohisa Yoshioka
    For the purpose of efficient separation of sulfate ions from magnesium ions, novel negatively-charged nanofiltration membranes were developed by incorporating the monoamines 4-aminobenozic acid, aniline-2,5-disulfonic acid monosodium salt, and iminodiacetic acid (IDA) during interfacial polymerization of piperazine (PIP) and trimesoyl chloride. PIP-amide membranes without these monomers tended to reject magnesium ions as well as sulfate ions. In contrast, incorporation of the monoamines resulted in large molecular weight cut-offs and large negative charge densities thanks to carboxyl or sulfo terminal groups of the monoamines, which enabled preferential permeation of magnesium ions while maintaining high rejection of sulfate ions. In particular, the IDA-incorporated nanofiltration membrane with an IDA to PIP + IDA mass ratio of 0.40 showed high rejection of sulfate ions with low rejection of magnesium ions even when the concentration of sodium chloride was much higher than that of magnesium sulfate. This result indicates the feasibility of the developed membrane for magnesium recovery from desalinated seawater in the electrodialysis process for table salt production.
    ELSEVIER, May 2020, SEPARATION AND PURIFICATION TECHNOLOGY, 239, English
    [Refereed]
    Scientific journal

  • Guanying Dong, Hiroki Nagasawa, Liang Yu, Meng Guo, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    We developed a procedure that saves significant amounts of energy during the separation of organic liquids via organic solvent reverse osmosis (OSRO). The proof-of-concept was confirmed using theoretical calculation to demonstrate energy-consumption at less than 1/100th and 1/10th that of conventional distillation and pervaporation (PV), respectively. Bis(triethoxysilyl)acetylene (BTESA)-derived organosilica membranes consisting of a SiO2-ZrO2 intermediate layer and an alpha-Al(2)O(3 )support were evaluated by challenging a series of azeotmpic mixtures of methanol/toluene, methanol/methyl acetate, methanol/dimethyl carbonate (DMC), and methanol/ methyl tert-butyl ether (MTBE). BTESA membranes showed excellent size- and/or shape-sieving properties and remarkable levels of organic-tolerance with an ultrahigh methanol flux that outperforms state-of-the-art polymeric membranes. In particular, the robust ceramic support and rigid organosilica networks endowed the resultant membranes with the ability to withstand transmembrane pressures as high as 18 MPa.
    ELSEVIER, Mar. 2020, JOURNAL OF MEMBRANE SCIENCE, 597, English
    [Refereed]
    Scientific journal

  • Eiji Kamio, Masashi Tanaka, Yuta Shirono, Yujeong Keun, Farhad Moghadam, Tomohisa Yoshioka, Keizo Nakagawa, Hideto Matsuyama
    A hollow fiber-type facilitated transport membrane composed of an ionic liquid-based polymer network gel layer with amino acid as the CO2 carrier and a porous polysulfone support membrane was developed. A polymerized ionic liquid-based gel layer with glycinate was the best amino acidate examined in this study. Filtering the gel particles by the support membrane, a gel layer with a thickness of about 1 mu m could be formed on the inner surface of the support. The developed membrane showed promising potential for CO2 capture from air because of its high CO2 permeance of about 1400 GPU and excellent CO2/N-2 selectivity of more than 2000 under atmospheric pressure with CO2 pressure of 0.1 kPa at 30 degrees C. Because the developed membrane showed significant diffusion resistance in the pores of the support membrane, it was suggested that the performance of the composite membrane could be improved by optimizing the support membrane structure.
    AMER CHEMICAL SOC, Feb. 2020, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 59(5) (5), 2083 - 2092, English
    [Refereed]
    Scientific journal

  • Misato Kunimatsu, Keizo Nakagawa, Tomohisa Yoshioka, Takuji Shintani, Tomoki Yasui, Eiji Kamio, Shik Chi Edman Tsang, Jianxin Li, Hideto Matsuyama
    Membranes assembled by two-dimensional (2D) nanosheets have high potential for advanced molecular separation. The intercalation of nanomaterials into the laminar membrane is a promising strategy to control the nanochannel structure. We present 2D niobate nanosheet (NbN)-Graphene oxide (GO) composite membranes fabricated by simple vacuum filtration. The effect of the weight ratio of NbN/GO on the membrane structures and performances is investigated. The NbN-rich membranes have a more stable structure in the wet condition and a membrane structure with a larger channel size compared with GO-rich membranes. Especially, NbN55-GO45 (weight ratio of NbN/GO = 55/45) shows a superior water permeability of 20 L m(-2) h(-1) bar(-1), which is around 6 times higher than an NbN membrane (NbN100) and 2 times higher than a GO membrane (GO100), while maintaining good rejection abilities of an anionic dye (nearly 100% for Evans blue) and salt (60% for Na2SO4). Different models for the water pathway through nanochannels can be classified according to the composite ratio of the NbN-GO membranes.
    ELSEVIER, Feb. 2020, JOURNAL OF MEMBRANE SCIENCE, 595, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Chuanjie Fang, Saeid Rajabzadeh, Hao-Chen Wu, Xinyu Zhang, Noriaki Kato, Misato Kunimatsu, Tomohisa Yoshioka, Hideto Matsuyama
    In this study, a combination of experimental results and molecular dynamics (MD) simulation was employed to understand the mass transfer between the extruded solvent and polymer solution by using a triple-orifice spinneret in the thermally induced phase separation (TIPS) process. Extruding solvent at the outer layer of the extruded polymer solution with different air gap distances controlled the mass transfer before phase separation. The progressive change in the phase separation mechanism, from the liquid-liquid to the solid-liquid induced by mass transfer, played a determined role in tailoring the composite-like structure. The moving of polymer or diluent from the bulk solution to the contact interface changed the polymer surface concentration and subsequently affected the membrane surface pore structure. The MD calculation results elucidated the mass transfer of the solvent and the polymer solution, which drastically affected the membrane structure. The formed spherulite-embedded bicontinuous structure clearly improved the membrane water permeation stability from 52 to 98%. On the other hand, by altering the air gap distances, the membrane water permeation flux enhanced in a wide range from 266 to 1429 L m(-2) h(-1) bar(-1). A new relationship between permeation flux and permeation stability was obtained, which can be utilized as a guideline for the engineering of hollow fiber membranes with high and stable permeability in the TIPS process.
    ELSEVIER, Feb. 2020, JOURNAL OF MEMBRANE SCIENCE, 595, English
    [Refereed]
    Scientific journal

  • Shintani Takuji, Nakagawa Keizo, Yoshioka Tomohisa, Matsuyama Hideto
    Separation of organic solvent by membrane is an emerging technology for the purification or separation of organic solvents. In this study, game changing OHF (Organic solvent Hyper Filtration) membranes and their applications are under development to realize the replacement from energy–consuming distillation to energy–efficient membrane process. Nano filtration (NF)–type hollow fiber OHF membrane was developed by TIPS (Thermally–Induced Phase Separation) method using solvent–resistant polymers such as nylon 6. The prepared membranes showed methanol (MeOH) permeability of > 2 LMH (L･m–2･h–1) with molecular weight cut–off (MWCO) of about 1,000 and stability for >1 month. Reverse osmosis (RO)–type organic composite OHF membrane was developed by the interfacial polymerization method. A highly cross-linked polyamide layer was prepared on a solvent resistant support membrane. The membrane showed selectivity for MeOH against toluene (TOL) in separation test using MeOH/TOL mixture. Membrane performance was Rej.＝ 65% Flux ＝ 16 LMH at 40 bar. The stability was > 2 weeks. NF–type TiO2/ZrO2 ceramic composite OHF membrane was developed using organic chelating ligands (OCL) as a pore size–fixing spacer. The membrane showed high permeability for organic solvents such as hexane (26 LMH) and MeOH (25 LMH) at 6 bar with MWCO of about 1,000 and stability of > 1 week. NF–type inorganic nanosheet OHF membrane was developed by laminating nanosheets of niobate and/or graphene oxide onto solvent resistant support membrane using chemical binders. The membrane showed relatively high MeOH permeability (11 LMH at 2 bar) and good rejection against organic dyes such as Evans blue (Mw : 960.8) with 87%.
    THE MEMBRANE SOCIETY OF JAPAN, 2020, MEMBRANE, 45(4) (4), 165 - 170, Japanese

  • Yuki Sada, Tomohisa Yoshioka, Keizo Nakagawa, Takuji Shintani, Ryosuke Iesako, Eiji Kamio, Hideto Matsuyama
    Organic chelate ligand (OCL)-templated TiO2-ZrO2 nanofiltration membranes were fabricated. Three types of OLCs, isoeugenol (ISOH), 2,3-dihydroxynaphthalene (DHN), and ethyl acetoacetate (EAA) were examined for use in the preparation of a TiO2-ZrO2 thin separation layer. All employed OCLs were completely decomposed and removed with firing at 500 degrees C under air, but OCL-templated TiO2-ZrO2 composite materials maintained their amorphous structure after firing. ISOH- and DHN-templated TiO2-ZrO2 composite powder samples were more microporous with a higher BET specific surface area than ordinary pure TiO2-ZrO2 composite material without OCL. On the other hand, EAA-templated TiO2-ZrO2 had a less-microporous structure similar to that of non-templated TiO2-ZrO2 powder. The average pore sizes of ISOH-, DHN-, and EAA-templated membranes were 2.0, 2.0, and 1.4 nm, respectively, while that of a non-templated TiO2-ZrO2 membrane was 1.4 nm. ISOH and DHN were more effective as an OCL for changing the characteristics of ordinary TiO2-ZrO2 composite materials. The molecular weight cut-off (MWCO) of OCL-templated TiO2-ZrO2 membranes was 600-1000 g/mol, and water permeability was 3.7-11.41/(m(2) h bar) (LMH/bar). OCLs could be useful for improvements in the water permeability of porous ceramic membranes that retain their solute rejection or separation characteristics.
    ELSEVIER, Dec. 2019, JOURNAL OF MEMBRANE SCIENCE, 591, English
    [Refereed]
    Scientific journal

  • Lei Zhang, Yuqing Lin, Haochen Wu, Liang Cheng, Yuchen Sun, Tomoki Yasui, Zhe Yang, Shengyao Wang, Tomohisa Yoshioka, Hideto Matsuyama
    Membrane fouling caused by oil or other pollutants is one of the major challenges for membrane separation technology used for emulsified oil/water purification. Aiming at the realization of comprehensive fouling-resistant/fouling-release properties, and the further achievement of long-term cyclic separation, an ultrathin silica (SiO2) layer is conformally engineered onto a porous polyketone (PK) substrate via the electrostatic attraction force silicification process. This in situ silicification forms an ultrathin and superhydrophilic/underwater superoleophobic interface structure that allows the realization of ultrahigh water permeance up to 7533 L m(-1) h(-1) bar(-1), an exceptionally high emulsion flux up to 6000 L m(-1) h(-1) bar(-1) (close to pure water permeance), and a high rejection of >99.9% against various oily emulsions. The unique design of the superhydrophilic silicification layer grown on the hydrophilic PK substrate also endowed the membrane with comprehensive antifouling properties against a broad range of oily emulsions containing various pollutants such as proteins, surfactants, and other natural organic materials (NOM), from which a nearly 100% recovery ratio of permeation flux could be obtained after several cycles of oily emulsion filtration. The use of an inorganic SiO2 modified layer incorporated into a highly chemically inert PK substrate (SiO2-d-PK membrane) also enabled the application of the SiO2-d-PK membrane under more challenging conditions, where its great tolerance and long-term stability toward salty and strongly acidic/alkaline solutions and various organic solvents were further demonstrated. Overall, this study provides an insight into engineering an ultrathin membrane with ultralow fouling-propensity for treating challenging oily emulsions.
    ROYAL SOC CHEMISTRY, Nov. 2019, JOURNAL OF MATERIALS CHEMISTRY A, 7(42) (42), 24569 - 24582, English
    [Refereed]
    Scientific journal

  • Youhei Yabuno, Kota Mihara, Kensaku Komatsu, Shigetaka Shimamura, Keizo Nakagawa, Takuji Shintani, Hideto Matsuyama, Tomohisa Yoshioka
    We developed a new hydrophilization method that we refer to as polyvinylalcohol (PVA) diffusion. This new method modifies the entire surface area of a hollow fiber membrane by diffusing PVA from the bore fluid to the outer surface. This method was used to prepare hydrophilized polyvinylidene difluoride (PVDF) hollow fiber membranes (PVA-PVDF). A hydrophilized polysulfone (PSf) hollow fiber membrane (PVA-PSf) was also prepared for reference. Interfacial polymerization was performed on the outer surface of the hollow fiber substrates during the preparation of polyamide (PA) thin-film composite membranes. This study examined the hydrophilicity effect that these modified support layers exert on the performance of membranes during reverse osmosis (RO) and forward osmosis (FO). Compared with PSf membranes, PVDF membranes had a higher physical strength of over 10 MPa, which was credited to production using a thermally induced phase separation (TIPS) process compared to the non-solvent induced phase separation (NIPS) process that is used to produce PSf membranes. The TIPS process could be useful for developing mass production techniques such as roll-to-roll processing. Comparisons of the RO test performance of hydrophilized PVDF membranes (PA-PVA-PVDF, PA-PVDF) showed that the 1000 ppm of NaCl rejection of hydrophilized support membrane was higher than that of nonmodified support membranes. The FO performances were similar regardless of whether or not the support membranes were hydrophilized when measured under wet conditions. In measurements under dry conditions, however, the performance was significantly lowered in the PA-PVDF membrane that was not hydrophilized. Hydrophilization via PVA diffusion effectively produced equivalent FO membrane performances under either wet conditions or dry conditions.
    AMER CHEMICAL SOC, Nov. 2019, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 58(47) (47), 21691 - 21699, English
    [Refereed]
    Scientific journal

  • Tomohisa Yoshioka, Akihiro Nakata, Kuo-Lun Tung, Masakoto Kanezashi, Toshinori Tsuru
    Microporous silica membranes have silica polymer network voids smaller than 3 angstrom where only small gas molecules such as helium (2.6 angstrom) and hydrogen (2.89 angstrom) can be transported. These silica membranes are highly expected to be available for H-2 separation. In order to examine gas permeation mechanisms in the silica polymer network voids, factors such as membrane porous structures, gas diffusivity, and gas permeability were studied via membrane permeation molecular dynamics simulation. The thermal motions of silica membrane constituent atoms were examined according to classic harmonic oscillation potential using a suitable amorphous silica structure and non-equilibrium molecular dynamics (NEMD) simulations of gas permeation. The dynamic model successfully simulated the gas permeation characteristics in an amorphous silica membrane with a suitable Hooke's potential parameter. The introduction of the oscillative thermal motion of the membrane atoms enhanced gas diffusivity. Helium and hydrogen diffusivity and permeability were analyzed using gas translation (GT) and solid vibration (SV) models. The diffusion distance of gas molecules between adsorption sites was around 5.5-7 angstrom. The solid-type vibration frequencies of gas molecules in the site were on the order of 10(13) and were reasonably smaller for heavier helium than for hydrogen. Both the GT and SV models could explain the temperature dependency of helium and hydrogen gas diffusivities, but the SV model provided a more realistic geometrical representation of the silica membrane. The SV model also successfully explained gas permeability in an actual silica membrane as well as the virtual amorphous silica membrane.
    MDPI, Oct. 2019, MEMBRANES, 9(10) (10), English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Tomohisa Yoshioka, Rina Kunimori, Ikumi Hisaoka, Hiroki Nagasawa, Masakoto Kanezashi, Toshinori Tsuru
    Liquid-phase permeation was simulated in nano-scale pores via non-equilibrium molecular dynamics (NEMD). Two virtual cristobalite membranes were prepared with pore diameters of 1.7 and 2.4 nm. NEMD simulation system was employed as an ideal experimental system to calculate the affinity between liquid argon molecules and membrane materials during permeation. When argon-membrane interactions decreased, permeation flux increased. With a smaller interaction the permeation flux exceeded the value posited by the Hagen-Poiseuille theorem, while a lower-than-expected level of permeation flux was observed when the interactions with the pore surface became greater. We focused on the viscosity change of liquid in a nano-scale pore due to attractive or repulsive interactions with the pore surface, and a mathematical model for describing the liquid permeation flux in a nanopore was proposed by solving the Navier-Stokes equation by considering the viscosity distribution of a liquid confined in a pore. The local viscosity of a liquid confined in a pore was calculated from the total potential distribution in the pore based on the Andrade equation. The predicted level of permeation flux, the velocity profiles of different pore sizes, and the interactions of the pore models all showed good agreement with the NEMD simulation results.
    ELSEVIER SCIENCE BV, Aug. 2019, SEPARATION AND PURIFICATION TECHNOLOGY, 220, 259 - 267, English
    [Refereed]
    Scientific journal

  • Hao-Chen Wu, Tomohisa Yoshioka, Keizo Nakagawa, Takuji Shintani, Daisuke Saeki, Hideto Matsuyama
    Molecular simulation was adopted to investigate and compare the water-channel performance of a common Amphotericin B_Ergosterol (AmBEr) model with that of two hydrophobically modified Amphotericin B_Ergosterol (C3deOAmBEr) models. Structural characteristics and transport performances were also examined. The energy levels of the simulation models were explored to determine the stability of each channel. The hydrogen bonds between the Amphotericin B monomers and the water molecules within each channel illustrated the affinity of the channel water. Molecular dynamics (MD) and Monte Carlo (MC) methods were adopted to investigate the diffusion and sorption behaviors of the water molecule transport performance, respectively. Furthermore, the effect of modification was studied to reveal the features of the modified channel simulation model. In the case of the modified C3deOAmBEr model, the results indicated that modification led to hydrophobic properties in the channel. Although modification reduced the attractive forces and led to lower adsorbability within the channel, the special structure of the Amphotericin B monomer showed interesting results. In the case of the modified model, the hydrophilic entrance of the channel contributed to the attraction of water molecules, which facilitated a high level of water permeability. The MD and MC simulation methods enabled an illustration of the properties and performance on a microscopic level.
    ELSEVIER SCIENCE BV, Aug. 2019, JOURNAL OF MEMBRANE SCIENCE, 583, 49 - 58, English
    [Refereed]
    Scientific journal

  • Yuchen Sun, Yuqing Li, Lifeng Fang, Lei Zhang, Liang Cheng, Tomohisa Yoshioka, Hideto Matsuyama
    Fouling problems caused by oil and other pollutants is one of the most severe challenges for membranes used for purification of comprehensive oil-in-water emulsions. Poly(tetrafluoride-r-vinylpyrrolidone) (F-VP) with low-adhesive superoleophobicity is a class of novel material for fouling-repellent membrane modification to achieve highly-efficient separation of complex oily wastewater. In this work, the construction of an ultrathin F-VP layer with a controllable thickness of 2 mu m supported by polyvinylidene difluoride (PVDF) substrate was achieved, via an extremely simple, scalable and one-step surface modification process. Benefiting from the ultrathin modification F-VP layer, the resultant F-VP/PVDF membrane exhibited a superior comprehensive fouling-resistant and fouling releasing property, while maintaining a high mass-transfer efficiency without significant permeance sacrificing. The intrinsically non-fouling nature of F-VP modification layer endowed the F-VP/PVDF membrane with superoleophobic property to various oils, superhydrophilic/under oil superhydrophilic properties, and excellent antifouling property for comprehensive oil-in-water emulsions. The F-VP/PVDF membrane has high water permeance of 4612 L m(-1) h(-1) bar(-1), and high emulsion permeance of 461 L m(-1) h(-1) bar(-1) (10000 ppm soybean oil-in-water emulsion) with high rejection ratio of > 99.9%, and an outstanding, stable fouling-resistant and fouling-releasing property of similar to 93% flux recovery over 5-time continuous cyclic tests. Overall, this work provides an insight into a facile preparation of advanced composite membrane with ultralow fouling-propensity property, which shows great potential in treating practically challenging emulsified wastewater.
    ELSEVIER SCIENCE BV, Aug. 2019, JOURNAL OF MEMBRANE SCIENCE, 584, 161 - 172, English
    [Refereed]
    Scientific journal

  • Keizo Nakagawa, Tomohiro Sera, Misato Kunimatsu, Hiroharu Yamashita, Tomohisa Yoshioka, Takuji Shintani, Eiji Kamio, Shik Chi Edman Tsang, Hideto Matsuyama
    Niobate nanosheet membranes were fabricated by vacuum filtration using niobate nanosheets prepared by the hydrothermal method (HT-NbO membranes) and the exfoliation method (EX-NbO membranes). Membrane structure, water permeance and separation performance for these membrane types were measured and compared. Both membrane types had a dense structure and retained high structural stability in water via chemical cross-linking between sheets. The difference of the intercalated molecules and interaction between nanosheets affected the interlayer distance of the membranes. As a result, higher water permeance but lower rejection of polyethylene glycol, Na2SO4 and Acid Red 265 was observed for EX-NbO membranes than for HT-NbO membranes. This is due to the formation of larger nanochannels in EX-NbO membranes. A model of a water pathway through nanochannels based on void structure proposed for the HT-NbO membranes can also be applied for EX-NbO membranes.
    ELSEVIER SCIENCE BV, Jul. 2019, SEPARATION AND PURIFICATION TECHNOLOGY, 219, 222 - 229, English
    [Refereed]
    Scientific journal
    Link to Kobe Univ. Repository (Kernel)

  • Molecular simulation of adsorption behavior of silica nanoparticle onto a polymeric membrane surface in water
    Yu Fujimura, Takahiro Kawakatsu, Keisuke Okada, Tomohisa Yoshioka
    Jul. 2019, MEMBRANE, 44(4) (4), 192 - 198, Japanese
    [Refereed]
    Scientific journal

  • Zhe Yang, Daisuke Saeki, Hao-Chen Wu, Tomohisa Yoshioka, Hideto Matsuyama
    Biofouling is a major drawback for most polyamide reverse osmosis (RO) membranes, which results in water flux decline and higher energy demand. To prevent biofouling, it is important to minimize the interaction between bacterial and membrane surfaces. In this research, we investigated the influence of surface modification with various hydrophilic polymers on biofouling behavior. First, polyamide RO membranes were modified with well-structural controlled hydrophilic polymers, poly(2-hydroxyethyl methacrylate) (pHEMA), poly[poly(ethylene glycol)methacrylate] (pPEG), and poly[Inda]) was fabricated via a casting method, displaying excellent mechanical strength and high CO2 separation performance. Changes in the cross-linker loading of the PMAPTAC network were found to significantly impact the CO2 separation performance of the ion-gel membrane. For instance, as the cross-linker loading was decreased from 4 to 0.5 mol.%, the CO2 permeability and CO2/N-2 selectivity increased from 2254 to 7569 Barrer and from 130 to 210, respectively. The network structure and mechanical properties of the fabricated ion gels was also strongly dependent on the cross-linker loading of the PMAPTAC network, with excellent strength obtained at decreased loadings. The CO2 transport properties of the DN ion-gel membranes were substantially improved by increasing the [P-222(101)][Inda] content, which was mainly attributed to two cooperative factors: (1) carrier content increase, resulting in a large driving force for the diffusion of the CO2-complex and (2) decrease of the polymer network content, resulting in lower diffusion resistance. The proportional enhancement of CO2 permeance with reducing ion-gel membrane thickness implied that diffusion is the rate-determining step of CO2 permeation.
    ELSEVIER SCIENCE BV, May 2017, JOURNAL OF MEMBRANE SCIENCE, 530, 166 - 175, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Yuta Yamamoto, Nobukazu Tsuda, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Microporous silica membranes with high permselectivity are fabricated by atmospheric-pressure plasma enhanced chemical vapor deposition (AP-PECVD) using hexamethyldisiloxane as the precursor in plasma working gases of pure argon, and mixture of argon with oxygen or nitrogen. A silica membrane grown using plasma composed of a mixture of argon and nitrogen displays highly efficient gas separation, with selectivities for He/N-2 and He/SF6 of 196 and 820, respectively, and He permeance of 1.1x10(-7) mol m(-2) S-1 Pa-1 at 50 degrees C. Characterization of the membranes by FTIR and X-ray photoelectron spectroscopies reveals a relatively high concentration of carbon remains in the membrane grown using a mixture of argon and nitrogen. Annealing at elevated temperature after plasma deposition improves the permselectivity of the membranes. After annealing at 300 degrees C, the permeance of He at 50 degrees C increased to 4.0x10(-7) mol m(-2) s(-1) Pa-1 with no marked decrease of selectivity (He/N-2 =98, He/SF6 =770). The annealed membrane also exhibits remarkable permselectivity for CO2, showing selectivities for CO2/N-2 and CO2/CH4 of 46 and 166, respectively, with CO2 permeance of 1.9 x10(-7) mol m(-2) s(-1) Pa-1 at 50 degrees C. AP-PECVD shows great promise to fabricate microporous silica membranes highly permselective for gas separation.
    ELSEVIER SCIENCE BV, Feb. 2017, JOURNAL OF MEMBRANE SCIENCE, 524, 644 - 651, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Mai Nishibayashi, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    A novel approach to the preparation of polymer-supported silsesquioxane membranes is developed via photo-induced sol-gel processing. An organically bridged silsesquioxane thin layer by coating a silsesquioxane sol with a photo-acid generator onto a polymeric SPES/PSF composite nanofiltration membrane followed by irradiation with UV at room temperature. This polymer-supported silsesquioxane membrane derived from 1,2-bis(trimethoxysilyl) ethane displays selective water permeation with a water permeance of 3.0 x 10(-6) mol m(-2) s(-1) Pa-1, and shows a separation factor of 99 in the pervaporation of a 90 wt% isopropanol aqueous solution.
    ROYAL SOC CHEMISTRY, 2017, RSC ADVANCES, 7(12) (12), 7150 - 7157, English
    [Refereed]
    Scientific journal

  • Abdul Rajjak Shaikh, Hamed Karkhanechi, Eiji Kamio, Tomohisa Yoshioka, Hideto Matsuyama
    Global warming is occurring because of emission of greenhouse gases due to human activities. Capture of CO2 from fossil-fuel industries and absorption of CO2 for natural gas sweetening are crucial industrial tasks to address the threat from greenhouse gases. Amino acid ionic liquids (AAILs) are used for reversible CO2 capture. In this study, the effect of CO2 chemisorption on tetramethylammonium glycinate ([N-1111][GLY]), tetrabutylammonium glycinate ([N-4444] [GLY]), and 1,1,1-trimethylhydrazinium glycinate ([aN(111)][GLY]) were analyzed using density functional theory (DFT) and molecular dynamics (MD) studies. Density functional theory studies predicted different reaction pathways for CO2 absorption on [GLY] and [aN(111)](+). The activation energy barriers for CO2 absorption on [GLY](-) and [aN(111)](+) are 52.43 and 64.40 kJ/mol, respectively. The MD results were useful for mimicking the reaction mechanism for CO2 absorption on AAILs and its effect on physical properties such as the fractional free volume, diffusion coefficient, and hydrogen bonding. Dry and wet conditions were compared to identify factors contributing to CO2 solubility and selectivity at room temperature and elevated temperature. Hydrogen bonding between ion pairs was used to understand the increase in viscosity after CO2 absorption. The MD studies revealed that glycinate and related products after CO2 absorption contribute the most to the increase in viscosity.
    AMER CHEMICAL SOC, Dec. 2016, JOURNAL OF PHYSICAL CHEMISTRY C, 120(49) (49), 27734 - 27745, English
    [Refereed]
    Scientific journal

  • Xin Yu, Lie Meng, Takuya Niimi, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Organosilica microporous membranes were fabricated from 1, 2-bis (triethoxysilyl) ethane (BTESE)-derived sols prepared in acidic pH via the pH-swing method. This method includes two steps whereby a specific amount of NH3 was added into the acid sols and switched to acid after a reaction of several minutes. We found that the size of the BTESE-derived sols by pH-swing could be controlled via the H2O/BTESE molar ratio and the reaction time in alkali. Under the same H2O/BTESE ratio of 60, the BTESE-derived sols prepared in the pH-swing method showed an increase sol size in contrast with the acid method, and the sol size was easily controlled by the dominating reaction in alkali pH - the condensation reaction. Gas permeation results showed that some gases (He, H-2, N-2, C3H8, SF6) permeated the membrane that was prepared using the pH-swing sols (pH-swing membrane) at approximately twice the rate shown by the membrane prepared using acid sols (acid membrane); H-2 permeance levels of the pH swing membrane and the acid membrane were 3.4 x 10(-6) and 1.6 x 10(-6) mol m(-2) s(-1) Pa-1 at 200 degrees C, respectively. The pH-swing membrane also maintained similar H-2/C3H8 permeance ratios of ranging from 2600 similar to 5800, confirming that pH-swing processing is an innovative method for improvement in the gas permeance of BTESE-derived organosilica membranes. One possible reason for these results could be that the membranes prepared using the pH-swing sols increased the size of the sols, which reduced the sol penetration into the intermediate layer. Moreover, the high cross-linking that was caused by pH swing increased the thermostability of the BTESE-derived organosilica networks. The CO2/CH4 and CO2/N-2 permeance ratios for the pH-swing membrane were as high as 90 and 28, respectively, at 50 degrees C. (C) 2016 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Aug. 2016, JOURNAL OF MEMBRANE SCIENCE, 511, 219 - 227, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Shuji Miyauchi, Shinjiro Hayakawa, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    Metal-doped organosilica membranes for C3H6/C3H8 separation were fabricated via a sol-gel method. Al and Ag was selected as a doping material in the fabrication of metal-doped bis (triethoxysilyl) methane (BTESM) membranes, and the effects that doping materials exerted on the organosilica network size and on the C3H6/C3H8 permeation properties were evaluated. Gas permeance ratios such as H-2/CH4, H-2/C3H6, H-2/C3H8, and C3H6/C3H8 were approximately independent of Ag concentration, indicating that network size did not change when doped Ag existed as Ag ions in BTESM networks, as suggested by the X-ray absorption fine structure (XAFS) spectrum. On the other hand, when Al was doped into BTESM, each permeance decreased as Al concentration increased, and the selectivity (H-2/N-2, H-2/CH4) increased largely because of enhanced molecular sieving separation by densified networks. Ag-BTESM membranes showed negative values for activation energy (similar to-10 kJ mol(-1)) for C3H6 permeation, which were a much smaller values than those for BTESM (similar to-7 kJ mol(-1)) and Al-BTESM (similar to-3 kJ moll) membranes. BTESM, Al-, and Ag-BTESM membranes showed values for alpha(mix) (binary separation) that were higher than those for ash, (single permeation) at 50 degrees C. For example, Ag-BTESM (Si/Ag = 9/1) membrane showed higher C3H6/C3H8 selectivity (= 32.5) by binary separation than selectivity (similar to 19) by single permeation at 50 degrees C, but the selectivity by binary separation was approximately the same, irrespective of a different pressure ratio (feed pressure/permeate pressure).
    JAPAN PETROLEUM INST, Jul. 2016, JOURNAL OF THE JAPAN PETROLEUM INSTITUTE, 59(4) (4), 140 - 148, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Takuya Matsutani, Toru Wakihara, Hiromasa Tawarayama, Hiroki Nagasawa, Tomohisa Yoshioka, Tatsuya Okubo, Toshinori Tsuru
    The fluorine doping of a silica matrix was proposed in the design of enlarged and uniform networks for highly permeable CO2/CH4 separation membranes. Fluorine doping effectively created a tunable network size, and the order of pore sizes increased with increases in the F concentration: F-SiO2 (F/Si = 2/8) > F-SiO2 (F/Si = 1/9) > SiO2. F-SiO2 (F/Si = 1/9) membranes showed high CO2 permeance (4.1 x 10(-7) mol m(-2) s(-1) Pa-1) with high CO2/CH4 selectivity (approximate to 300) at 35 degrees C, due to the enlarged and uniform networks compared with those of SiO2. Fluorine doping was effective in preventing the formation of a 2nd Si-O in the 4-membered ring (MR) of the SiO4 tetrahedra. F-SiO2 samples with smaller fractions of 4MR and a smaller ring in silica, contain large fractions of larger rings (> 5MR), resulting in enlarged network structure and an increase in the average pore size, which translates to a higher permeance for larger molecules.
    WILEY-V C H VERLAG GMBH, Apr. 2016, CHEMNANOMAT, 2(4) (4), 264 - 267, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Amorphous carbon membranes were successfully synthesized onto a SiO2-ZrO2/alpha-Al2O3 nanoporous substrate via plasma-enhanced chemical vapor deposition (PECVD) at room temperature. PECVD-derived amorphous carbon membranes exhibited molecular sieving properties, showing ideal selectivities of 23 and 1750 for He/N-2 and He/SF6, respectively, at 25 degrees C. The membrane maintained high selectivity even at high temperatures as high as 200 degrees C, indicating considerable stability of the plasma-deposited amorphous carbon layer.
    ROYAL SOC CHEMISTRY, 2016, RSC ADVANCES, 6(64) (64), 59045 - 59049, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Naoki Matsuda, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Bis(triethocysilyl)ethane (BTESE)-derived organosilica membranes were applied for the dehydration of aqueous isopropanol (IPA) solutions in pervaporation and vapor permeation. The stability of the membranes under high-water-content systems was demonstrated in pervaporation and vapor permeation. The membranes showed excellent stability in the long-term pervaporation of a 50 wt% IPA aqueous solution at 75 degrees C. The membranes were also stable in vapor permeation with a high-water-content stream (IPA concentration of 50 wt%) at 100 degrees C. These results clearly demonstrated that BTESE-derived organosilica membranes are applicable for the dehydration of high-water-content mixtures. The effect of the feed component and operating temperature on dehydration performance was also investigated. An analysis of the permeation resistance through the membranes was conducted based on a simple seriesresistance modeling approach and revealed that the permeation resistance of the support layer strongly inhibited the water permeability, particularly when the water content in the feed was high. (C) 2015 Elsevier B.V. All rights reserved.
    ELSEVIER, Jan. 2016, JOURNAL OF MEMBRANE SCIENCE, 498, 336 - 344, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Hitomi Sazaki, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    Organosilica membranes were fabricated under controlled sol-preparation conditions such as the ratio of triethoxysilane (TRIES) and vinyltrimethoxysilane (VTMS) and the hydrosilylation temperature. The single-gas permeation properties and hydrothermal stability of organosilica membranes were evaluated to clarify the relationship between hydrothermal stability and organosilica structure. Pt-catalyzed and thermally cured hydrosilylation was applied to evaluate the effect that hydrosilylation temperature exerts on the properties of membranes. Organosilica membranes (Pt-catalyzed hydrosilylation at 40 degrees C) showed H-2 permeance of approximately 10(-6) mol m(-2) s(-1) Pa-1 with H-2 selectivity (H-2/CH4:15, H-2/CF4:950) at 500 degrees C, and were stable under an oxidative atmosphere at 500 degrees C. The organosilica network size derived by thermal curing at 500 degrees C was smaller than that by Pt-catalyzed hydrosilylation, even though the units (Si-C-C-Si, Si-O-Si) were the same. Hydrosilylation reactivity derived by thermal curing (500 degrees C, N-2) strongly depended on the TRIES/VTMS (=H/V) ratio in the SQ sol, and an H/V ratio of 1.25 showed a higher level of hydrosilylation reactivity. Its hydrothermal stability was better than that of amorphous silica membranes, due to the incorporation of Si-(CH2)(2)-Si units in the networks via hydrosilylation, based on the decreased ratio of He and H-2 permeance, the He/H-2 permeance ratio, and the activation energy before/after steam treatment. (C) 2015 Elsevier B.V. All rights reserved.
    ELSEVIER, Nov. 2015, JOURNAL OF MEMBRANE SCIENCE, 493, 664 - 672, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Toshihiro Minamizawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Organosilica membranes for gas separation were prepared by plasma-enhanced chemical vapor deposition (PECVD) using three different types of silicon precursors: hexamethyldisiloxane (HMDSO), trimethylmethoxysilane (TMMOS), and methyltrimethoxysilane (MTMOS). Based on gas permeation measurement, the MTMOS-derived membrane showed the highest He/N-2 selectivity, followed by the TMMOS-derived and HMDSO-derived membranes. FT-IR characterization indicated that the HMDSO-derived membrane had the highest content of methyl group and the lowest Si-O-Si, while the methyl group content for the MTMOS-derived membrane was the lowest and Si-O-Si was the highest. These results suggest that the pore size of organosilica membranes could be tuned by changing the chemical structure of the silicon precursor. The MTMOS-derived membrane was further heat treated to determine the effect of thermal annealing on gas-permeation properties. The gas permeances were drastically improved by the thermal annealing. After heat treatment at 500 degrees C, the membrane showed a high H-2 permeance of 6.5 x 10(-7) mol/(m(2) s Pa) with a H-2/SF6 selectivity of 410 at 200 degrees C, arid 5.6 x 10(-7) mol/(m(2) s Pa) with a H-2/SF6 selectivity of 360 at 50 degrees C. (C) 2015 Elsevier B.V. All rights reserved.
    ELSEVIER, Sep. 2015, JOURNAL OF MEMBRANE SCIENCE, 489, 11 - 19, English
    [Refereed]
    Scientific journal

  • Gang Li, Hye Ryeon Lee, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    A modified gas-translation (GT) model based on a GT mechanism was successfully applied to the pore-size evaluation and gas transport behavior analysis of microporous membranes with different pore-size distributions. Based on the gas permeation results of three microporous membranes derived from different alkoxides, the effects of activation energy and the selection of a standard gas on the pore-size evaluation were discussed in a comparative study. The presence of nano-sized defects had an important influence on the gas permeation performance of microporous membranes, depending largely on the original pore size of the membrane in question. Moreover, the gas-separation effect of the pore-size distribution in a silica membrane was theoretically studied and revealed a significant increase in gas permeance for relatively large gas species but not for small ones. (c) 2015 American Institute of Chemical Engineers AIChE J, 61: 2268-2279, 2015
    WILEY-BLACKWELL, Jul. 2015, AICHE JOURNAL, 61(7) (7), 2268 - 2279, English
    [Refereed]
    Scientific journal

  • Lie Meng, Xin Yu, Takuya Niimi, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    The dehydrogenation of methylcyclohexane (MCH) to toluene (TOL) for hydrogen production was theoretically and experimentally investigated in a bimodal catalytic membrane reactor (CMR), that combined Pt/Al2O3 catalysts with a hydrogen-selective organosilica membrane prepared via sol-gel processing using bis(triethoxysilyl) ethane (BTESE). Effects of operating conditions on the membrane reactor performance were systematically investigated, and the experimental results were in good agreement with those calculated by a simulation model with a fitted catalyst loading. With H-2 extraction from the reaction stream to the permeate stream, MCH conversion at 250 degrees C was significantly increased beyond the equilibrium conversion of 0.44-0.86. Because of the high H-2 selectivity and permeance of BTESE-derived membranes, a H-2 flow with purity higher than 99.8% was obtained in the permeate stream, and the H-2 recovery ratio reached 0.99 in a pressurized reactor. A system that combined the CMR with a fixed-bed prereactor was proposed for MCH dehydrogenation. (c) 2015 American Institute of Chemical Engineers AIChE J, 61: 1628-1638, 2015
    WILEY-BLACKWELL, May 2015, AICHE JOURNAL, 61(5) (5), 1628 - 1638, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Rui Matsugasako, Hiromasa Tawarayama, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    A new concept was proposed to control the pore size in a novel silica membrane. The tuning of the pore sizes in triethoxysilane (TRIES)-derived membranes was successfully conducted via an in situ reaction between NH3 and Si-H groups at high temperatures. The formation of Si-NH2 and/or Si-NH groups in the silica structure enhanced the hydrogen selectivity.
    ROYAL SOC CHEMISTRY, 2015, CHEMICAL COMMUNICATIONS, 51(13) (13), 2551 - 2554, English
    [Refereed]
    Scientific journal

  • Mai Nishibayashi, Hiroyuki Yoshida, Masamoto Uenishi, Masakoto Kanezashi, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    Silsesquioxane (SQ) membranes derived from 3-methacryloxy-propyltrimethoxysilane and bis(trimethoxysilyl) ethane were successfully fabricated at low temperature via photo-induced sol-gel processing. Radical and cationic polymerization of SQ membranes showed high degrees of separation factor and permeance for water/isopropanol separation in pervaporation.
    ROYAL SOC CHEMISTRY, 2015, CHEMICAL COMMUNICATIONS, 51(49) (49), 9932 - 9935, English
    [Refereed]
    Scientific journal

  • Genghao Gong, Jinhui Wang, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    In this study a new type of layered hybrid membrane was fabricated. This new membrane consisted of a thin organically bridged silica separation layer deposited onto the surface of a flexible polymeric membrane, NTR-7450 (Nitto Denko, japan), and was comprised of a sullonated polyethersulfone top layer and a porous polysulfone support. Using 1,2-bis(triethoxysilyl)ethane (BTESE) as a precursor, a continuous and defect-free BTESE separation layer was deposited onto the surface of a polymeric nanofiltration membrane via a facile, reproducible and scalable sol-gel spin-coating and low-temperature curing process. First, the optimal preparation conditions were established, which included the curing temperature and the spin-coating cycles. The membranes were then used for the vapor permeation dehydration of isopropanol-water solutions, and showed a stable water flux 01 2,3 kg/(m(2) h) and an improved separation factor of about 2500, which was an increase of approximately 5-fold compared with that of a polymeric nanofiltration membrane. ln addition, single-gas permeance through this membrane was also discussed and a modest H-2/N-2 selectivity of 26 was obtained, which approximated the performance of ceramic-supported BTESE-derived silica membranes. (C) 2014 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Dec. 2014, JOURNAL OF MEMBRANE SCIENCE, 472, 19 - 28, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Takuya Niimi, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    A modified gas-translation (GT) model was applied for the theoretical analysis of gas permeation through microporous organosilica membranes derived from bis(triethoxysilyl)ethane (BTESE) via a sol-gel method using different water/alkoxide molar ratios. The pore sizes of BTESE-derived membranes were quantitatively determined by normalized Knudsen-based permeance analysis, which was based on a modified-GT model, using experimentally obtained permeances of He, H-2, N-2, C3H8, and SF6. The pore sizes of BTESE-derived membranes were successfully controlled from 0.65 to 0.46 nm by increasing the H2O/BTESE ratio from 6 to 240. Furthermore, theoretical correlations of all possible pairs of permeance ratios were calculated based on the modified-GT model. The experimental data were in good agreement with the theoretical correlation curves, indicating that the modified-GT model can clearly explain gas permeation mechanisms through microporous membranes, and, thus, can be used to predict the gas permeation properties for these membranes. (c) 2014 American Institute of Chemical Engineers AIChE J 60: 4199-4210, 2014
    WILEY, Dec. 2014, AICHE JOURNAL, 60(12) (12), 4199 - 4210, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Shuji Miyauchi, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    The sal-gel method was applied to the fabrication of Al-doped bis (triethoxysilyl) methane (BTESM)derived membranes. The single-gas permeation properties for Al-doped BTESM-derived membranes were examined to evaluate the effect of aluminum concentration on amorphous silica network sizes. Each permeance was decreased with an increase in the Al concentration, and the H-2/CH4 and H-2/C3H8 permeance ratios increased with an increase in Al concentration. For example, an Al-doped BTESM (Si/Al= 8/2) membrane fabricated at 200 degrees C showed a H-2 permeance of 4.4 x 10(-7) mol m(-2) s(-1) Pa-1, which was approximately 1/10th that of a BTESM membrane fabricated at 200 degrees C. The H-2/CH4 and H-2/C3H8 permeance ratios were 60 and 2700 with Al doping, but 30 and 1000 without Al-doping, respectively. The activation energy of He, H-2, N-2, and CH4 permeation was increased with an increase in the Al concentration, indicating that the pore size of BTESM-derived networks was decreased with an increase in Al concentration. The decrease in BTESM-derived network sizes that resulted from an increase in the Al concentration can be ascribed to the absolute amount of Al incorporated into BTESM-derived networks and/or coordinated with Si-OH groups, as suggested by Al-27 MAS NMR. High C3H6/C3H8 permeance ratios of approximately 40 for Al-doped BTESM (Si/Al=9/1) membranes fabricated at 200 degrees C were achieved through the precise control of the silica network size via a spacer method using Si-C-Si units as well as the incorporation of Al in BTESM-derived networks. (C) 2014 Elsevier B.V. All rights reserved.
    ELSEVIER, Sep. 2014, JOURNAL OF MEMBRANE SCIENCE, 466, 246 - 252, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Takanori Sasaki, Hiromasa Tawarayama, Hiroki Nagasawa, Tomohisa Yoshioka, Kenji Ito, Toshinori Tsuru
    The sol-gel method was applied to fabrication of amorphous silica membranes, which have different silica network sizes caused by control of the calcination temperatures. The effects of fabrication temperature on small gas (He, H-2, Ne, NH3, CO2, N-2, and CH4) permeation properties through silica membranes were evaluated quantitatively using modified gas translation (GT) model. A silica membrane fired at 550 degrees C showed He and H-2 permeances of 8.6 X 10(-7) and 5.5 X 10(-7) mol m(-2) s(-1) Pa-1 with He/CH4 and H-2/CH4 permeance ratios of 2350 and 1500 at 500 degrees C, respectively. The thermal stability was dramatically improved by the fabrication of deposited silica glass intermediate layer because N-2 permeance showed slight change, and the membrane showed a H-2/N-2 permeance ratio above 100 even heat-treated at 750 degrees C. The estimated silica network size decreased from 0.385 to 0.347 nm when a membrane was fabricated at 750 degrees C, which was consistent with the trend in activation energy of gas permeation. H-2 molecules were more permeable than Ne when passing through amorphous silica membranes despite their larger molecular size (H-2, 0.289 nm; Ne, 0.275 nm), and the H-2/Ne permeance ratios were approximately the same as the Knudsen ratio and were independent of the activation energy of Ne permeation, which was almost the same as that of H-2 permeation.
    AMER CHEMICAL SOC, Sep. 2014, JOURNAL OF PHYSICAL CHEMISTRY C, 118(35) (35), 20323 - 20331, English
    [Refereed]
    Scientific journal

  • Genghao Gong, Jinhui Wang, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Using 1,2-bis(triethoxysilyl)ethane (BTESE) as a single precursor, a uniform, defect-free and perm-selective organosilica layer was successfully deposited onto porous polysulfone ultrafiltration (PSF-UF) supports via a simple sol-gel spin-coating and thermal-treatment process. The layered hybrid membranes, where BTESE-derived SiO2 is deposited on polymer supports, were applied to the vapor permeation dehydration of isopropanol-water (90/10 wt%) solutions at 105 degrees C, and demonstrated a water flux of 1.6 kg/m(2) h and a separation factor of 315 with no selectivity for a PSF-UF support. Long-term stability testing of vapor permeation also confirmed the excellent stability of these BTESE/PSF-UF layered hybrid membranes. Moreover, compared with porous PSF-UF supports, this layered hybrid membrane also showed improved gas separation performance and a moderate (approximate to 10) separation factor for H-2/N-2. (C) 2014 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Aug. 2014, JOURNAL OF MEMBRANE SCIENCE, 464, 140 - 148, English
    [Refereed]
    Scientific journal

  • Toshiya Fukumoto, Tomohisa Yoshioka, Hiroki Nagasawa, Masakoto Kanezashi, Toshinori Tsuru
    Sol-gel derived microporous amorphous TiO2-ZrO2-organic composite membranes were prepared by two different types of chelating ligands, cliethanolamine (DEA) and isoeugenol (2-merhoxy-4-propenyl-phenol, ISOH)) as reaction inhibitors for hydrolysis and condensation of Ti- and Zr-alkoxide. The structural properties of the composite gels were characterized via a thermogravimetric study (TG), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and N-2 adsorption analysis; and the optimized calcination atmosphere and temperature conditions for a microporous membrane were examined. A crack free thin (50 nm) TiO2-ZrO2-organic layer for gas separation was formed on a SiO2-ZrO2 intermediate layer (150 nm) supported on a macroporous alpha-Al2O3 substrate as an asymmetric membrane. Compared with DEA, more of the ISOH and its remnants effectively remained after calcination, which promoted higher permeance and selectivity as a rnicroporous gas separation membrane by forming bimodal microporous structures that narrowed the original TiO2-ZrO2 pores. A TiO2-ZrO2 membrane with [SOH calcined at 350 degrees C under a N-2 atmosphere showed He and CO2 permeances of 1.0 x 10(-6) and 2.0 x 10(-7) mol m(-2) s(-1) Pa-1, respectively, at 200 C. The CO2/N-2 permeance ratio was 64 at 200 degrees C and 46 at 35 degrees C. (c) 2014 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Jul. 2014, JOURNAL OF MEMBRANE SCIENCE, 461, 96 - 105, English
    [Refereed]
    Scientific journal

  • Rong Xu, Suhaina M. Ibrahim, Masakoto Kanezashi, Tomohisa Yoshioka, Kenji Ito, Joji Ohshita, Toshinori Tsuru
    Microporous organosilica membranes with ethane, ethylene, and acetylene bridges have been developed and the extensive microstructural characterization has been discussed in relation with separation properties of the membrane. The organosilica network structure and the membrane performances can be controlled by adjusting the flexibility, size, and electronic structure of the bridging groups. A relatively narrow size distribution was obtained for the novel acetylene-bridged sol by optimizing the sol synthesis. Incorporation of larger rigid bridges into organosilica networks resulted in a looser microstructure of the membrane, which was quantitatively evaluated by N-2 sorption and positron annihilation lifetime (PAL) measurements. Molecular weight cutoff (MWCO) measurements indicated that the acetylene-bridged membrane had a larger effective separation pore size than ethane- and ethylene-bridged membranes, leading to a relatively low NaCl rejection in reverse osmosis. In quantum chemical calculations, a more open pore structure and increased polarization was observed for the acetylene-bridged networks, which led to a significant improvement in water permeability. The present study will offer new insight into design of high-performance molecular separation membranes.
    AMER CHEMICAL SOC, Jun. 2014, ACS APPLIED MATERIALS & INTERFACES, 6(12) (12), 9357 - 9364, English
    [Refereed]
    Scientific journal

  • Takuya Niimi, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Kenji Ito, Toshinori Tsuru
    High-performance organic-inorganic hybrid silica membranes were developed for use in membrane reactors for methylcyclohexane (MCH) dehydrogenation to toluene (TOL). The membranes were prepared via sol-gel processing using bis(triethoxysilyl)ethane (BTESE). In particular, the effect of hydrolysis conditions (H2O/BTESE molar ratio) on membrane performance was extensively investigated. Characterization based on TO-MASS, FTIR, N-2 adsorption and positron annihilation lifetime (PAL) measurements of BTESE-derived silica gels revealed that the ethoxides of BTESE were almost completely hydrolyzed and the silica networks became dense by increasing the H2O/BTESE molar ratio from 6 to 240. BTESE-derived silica membranes showed a hydrogen permeance that was higher than 1 x 10 mol/ (m(2) s Pa). H-2/TOL selectivity increased from 100 to 10,000 by increasing the H20/BTESE molar ratio from 6 to 240, while keeping a hydrogen permeance of more than 1 x 10(-6) mol/(m(2)s Pa).In MCH dehydrogenation, a BTESE-derived silica membrane reactor with a Pt/gamma-Al2O3/alpha-Al2O3 bimodal catalytic layer achieved MCH conversion of 75% that was higher than the equilibrium conversion of 60%, and a hydrogen purity in the permeate stream of more than 99.9% at 230 degrees C. 2014 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Apr. 2014, JOURNAL OF MEMBRANE SCIENCE, 455, 375 - 383, English
    [Refereed]
    Scientific journal

  • Xiuxiu Ren, Kanji Nishimoto, Masakoto Kanezashi, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    Hybrid organosilica membranes have become attractive for industrial applications because of high performance and long-term stability. This work investigated the influence of water vapor on CO2 gas permeation through the hybrid membranes. Two types of organoalkoxysilanes, bis(triethoxysilyl)ethane (BTESE) and bis(triethoxysilyl)octane (BTESO), were used as precursors to prepare membranes via the sol-gel method. The two membranes showed distinct properties of porosity and water affinity because of the differences in the bridging methylene numbers between the two Si atoms. Under dry conditions, the BTESE and BTESO membranes showed CO2 permeances as high as 7.66 x 10(-7) and 6.63 x 10(-7) mol m(-2) S-1 Pa-(1) with CO2/N-2 selectivities of 36.1 and 12.6 at 40 degrees C, respectively. In the presence of water vapor, CO2 permeance was decreased for both membranes, but the effect of water vapor on CO2 permeation was slighter for BTESO membranes than it was for BTESE membranes because of more hydrophobicity and denser structures with a longer linking-bridge group. The hybrid organosilica membranes both showed good reproducibility and stability in water vapor.
    AMER CHEMICAL SOC, Apr. 2014, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 53(14) (14), 6113 - 6120, English
    [Refereed]
    Scientific journal

  • Jonathan Albo, Tomohisa Yoshioka, Toshinori Tsuru
    The highest CO2 solubility and commercially-available ionic liquid, 1-ethyl-3-methylimidazolium acetate ([emim][Ac]), was immobilized in porous Al2O3/TiO2 tubes in order to study the potential of using supported ionic liquid membranes based on ceramic supports for CO2/N-2 separation. The supported ionic liquid membranes (SILMs) were first prepared using a conventional immobilization procedure based on ionic liquid impregnation, and then, by coating the TiO2 mesoporous outer layer, reducing the membrane resistance to gas permeation.The permeation of these membranes to carbon dioxide and nitrogen was measured, yielding a CO2 permeance as high as P-CO2 = 2.78 +/- 0.11 x 10(-8) mol/(m(2) s Pa), with an ideal CO2/N-2 selectivity of alpha(CO2/N-2) = 30.72 +/- 0.86 for membranes prepared under the coating procedure, which outperformed the state of the art for CO2/N-2 separation in polymeric materials. The membrane stability tests demonstrated that the hydrophilic ceramic support was very effective for the immobilization of the liquid phase in the membrane for a period of 25 h and at applied feed pressures of 4 bar. Finally, the effect of water vapor in the gas stream and the effect of operation temperature on membrane separation performance were evaluated and compared.The high CO2 permeance values and comparable selectivity to polymeric materials may suggest the potential application of using Al2O3/TiO2 tubes in combination with [emim][Ac] ionic liquid for the selective removal/recovery of CO2 from a gas stream in industrial applications. (C) 2013 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Feb. 2014, SEPARATION AND PURIFICATION TECHNOLOGY, 122, 440 - 448, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Hitomi Sazaki, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    Thermally stable organosilica amorphous membranes were fabricated by in situ hydrosilylation of vinyl and hydrosilyl groups in Si precursors for the formation of a Si-C-C-Si unit, as well as the Si-O-Si unit via the conventional hydrolysis and condensation of silanol groups. Two types of SiOC membranes (VTT-type prepared by vinyltrimethoxysilane (VTMS), triethoxysilane (TRIES) and tetramethyldisiloxane (TMDSO); and VT-type prepared by VTMS and TRIES) that consisted of a Si-C-C-Si unit created by the hydrosilylation of vinyl and hydrosilyl groups in a Si precursor were fabricated at temperatures higher than 300 degrees C under N-2. Single-gas permeation properties for SiOC membranes at temperatures ranging from 100-500 degrees C were examined to determine the effect of a silica precursor on the size of an amorphous network. A SiOC membrane (VTT-type) fabricated at 400 degrees C under N-2 showed a H-2 permeance of 5.3 x 10(-7) mol m(-2) s(-1) Pa-1 with H-2/CO2, H-2/N-2, H-2/CH4 and H-2/CF4 permeance ratios of 5.6, 15, 18 and 485, respectively, at 400 degrees C. The permeance of H-2 for a VTT-type membrane heat-treated at 550 degrees C in air significantly increased from 5.3 x 10(-7) to 2 x 10(-6) mol m(-2) s(-1) Pa-1 with a decrease in the H-2/CF4 permeance ratio from 485 to 90 due to the combustion of the CH3 groups. The SiOC membrane (VTtype) showed high thermal stability in air at 550 degrees C with a H-2 permeance of 3.0 x 10(-7) mol m(-2) s(-1) Pa-1 and H-2/CH4 and H-2/CF4 permeance ratios of 50 and 400, respectively, at 400 degrees C.
    ROYAL SOC CHEMISTRY, 2014, JOURNAL OF MATERIALS CHEMISTRY A, 2(3) (3), 672 - 680, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Toshihiro Minamizawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Organosilica membranes for gas separation were prepared on porous substrates by means of plasma-enhanced chemical vapor deposition (PECVD) using hexamethyldisiloxane as a precursor. Before the deposition of organosilica membranes, two types of intermediate layers with different pore sizes, a TiO2 layer (d(p) approximate to 5 nm) and a SiO2-ZrO2 layer (1 nm), were prepared on alpha-alumina porous supports via a sol-gel method. The stability at high temperatures was evaluated by measuring the gas permeation characteristics before and after heat treatment. PECVD membranes deposited on a SiO2-ZrO2 intermediate layer were found to be more thermally stable than those deposited on a TiO2 intermediate layer. After the treatment at 500 degrees C, the membranes deposited on a SiO2-ZrO2 intermediate layer had a selectivity of similar to 1040 for He against SF6 with a He permeance of 1.41 x 10(-6) mol/(m(2) s Pa) at 50 degrees C, although the organosilica membranes were prepared at room temperature. On the other hand, the membrane deposited on a TiO2 intermediate layer became non-selective after heat treatment at 400 degrees C. The temperature dependence of single gas permeance for the membrane deposited on a SiO2-ZrO2 intermediate layer was measured after the high-temperature stability test. The permeation of He, H-2 and N-2 for the 200 degrees C-treated membrane showed an activated diffusion, while those for the 500 degrees C-treated membrane followed a Knudsen permeation, suggesting that heat treatment at 500 degrees C formed pores that allowed the permeation of molecules that were the size of N-2 (0.364 nm) and smaller. In addition, since the permeation of SF6 for the 500 degrees C-treated membrane showed an activated diffusion, the membrane should have a uniformed structure with a small number of pinholes. (C) 2013 Elsevier B.V. All rights reserved.
    ELSEVIER, Jan. 2014, SEPARATION AND PURIFICATION TECHNOLOGY, 121, 13 - 19, English
    [Refereed]
    Scientific journal

  • Suhaina M. Ibrahim, Rong Xu, Hiroki Nagasawa, Akinobu Naka, Joji Ohshita, Tomohisa Yoshioka, Masakoto Kanezashi, Toshinori Tsuru
    2,4,6-Tris[3(triethoxysilyl)-1-propoxy]-1,3,5-triazine (TTESPT) is a new precursor for preparing membranes. The TTESPT-derived silica membrane exhibits a significant degree of selectivity for C3H6-C3H8 similar to 37 at a permeation temperature of 50 degrees C, which greatly surpasses the upper-bounds of selectivity and permeance trade-off of carbon membranes. This indicates the potential for further development toward C3H6-C3H8 separation applications.
    ROYAL SOC CHEMISTRY, 2014, RSC ADVANCES, 4(24) (24), 12404 - 12407, English
    [Refereed]
    Scientific journal

  • Gang Li, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    To date, Ru is the most active single-metal catalyst known for ammonia decomposition, but its catalytic activity is support-dependent and structure-sensitive. Therefore, a unique support-anchored Ru nanoparticle with controllable size and morphology would be particularly important for high catalytic performance. In this work, we describe Ru nanoparticles supported by two-dimensional graphene nanosheets with a controlled nanoarchitecture that forms a novel composite catalyst that is capable of a high degree of ammonia decomposition. This high-quality Ru/graphene nanocomposite material was obtained via a cosolvent method (CS-Ru/graphene), in which ethylene glycol simultaneously acted as a solvent and a reductant, while water served only as a cosolvent. The abundant oxygen-containing functional groups of graphene oxide played extremely important roles in the growth of Ru nanoparticles on the resultant graphene nanosheets, as they promoted Ru nucleation and acted as anchor sites for the Ru nanoparticles. Moreover, the use of water as a cosolvent was an effective way to tune the Ru particle size and morphology and aid in the loading of the nanocomposite, resulting in dramatically enhanced catalytic activity in comparison with a composite prepared by using ethylene glycol as a single solvent (SS-Ru/graphene). The exceptional catalytic performance of CS-Ru/graphene was mainly ascribed to the novel graphene support that simultaneously combines a large specific surface area with excellent electronic conductivity, but also to the highly dispersive Ru nanoparticles that made up the nanocomposite with a controlled morphology and an optimal size.
    ROYAL SOC CHEMISTRY, 2014, JOURNAL OF MATERIALS CHEMISTRY A, 2(24) (24), 9185 - 9192, English
    [Refereed]
    Scientific journal

  • Suhaina M. Ibrahim, Rong Xu, Hiroki Nagasawa, Akinobu Naka, Joji Ohshita, Tomohisa Yoshioka, Masakoto Kanezashi, Toshinori Tsuru
    A promising new triazine-based nitrogen-rich organosilica (TTESPT) membrane has been developed for molecular separation processes in gas (gas separation) and liquid phases (reverse osmosis (RO)). By adjusting the H2O/TTESPT molar ratio, we found a promising technique for tuning the pore network of TTESPT membranes. An increase in the H2O/TTESPT molar ratio from 60 to 240 fully hydrolyzed all the ethoxide groups in the TTESPT membrane, which reduced the size of the pores in the silica pore network. A TTESPT membrane with a high H2O/TTESPT molar ratio exhibited a high degree of selectivity for H-2/SF6 (greater than 4000) at a permeation temperature of 200 degrees C. This membrane also demonstrated high sodium chloride (NaCl) rejection (>98.5%) with water permeability of >1 x 10(12) m(3) m(-2) s(-1) Pa-1 under operating conditions of 1 MPa and 60 degrees C during a RO experiment. As the operating temperature was increased from 25 to 60 degrees C, the NaCl rejection was constant without displaying the characteristic flux deterioration. This showed that the membrane retained a stable hybrid network structure.
    ROYAL SOC CHEMISTRY, 2014, RSC ADVANCES, 4(45) (45), 23759 - 23769, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Shoichi Sasaki, Takashi Kamada, Takuji Shintani, Tomomi Ohara, Hiroki Nagasawa, Keiya Nishida, Masakoto Kanezashi, Tomohisa Yoshioka
    A spray-assisted, 2-step interfacial polymerization (IP) of trimesoyl chloride (TMC)/m-phenylenediamine (MPD) was proposed for the preparation of polyamide (PA) membranes. In the first step, TMC/hexane solutions were sprayed onto MPD-impregnated polysulfone (PSI) supports for 10-60 s, followed by a second step where the first-step membranes made contact with the TMC/hexane solutions. It is noteworthy that water permeability was increased with spray time in the first step of the 2-step IP, showing approximately doubled values at the spray time of 20-30s, compared with 1-step PA/PSf composite membranes, while NaCl rejections were practically unchanged. With longer spray time (3060 s), water permeability decreased while NaCl rejection remained at the same level. A characterization of 1- and 2-step PA membranes, including FE-SEM and ATR-FTIR, revealed the formation of multilayered ridge-and-valley structures of polyamide from the spray-assisted IP steps, and it is suggested that the increased water permeability have been caused by the increased interfacial surface area of the 2-step PA membranes. (C) 2013 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Nov. 2013, JOURNAL OF MEMBRANE SCIENCE, 446, 504 - 512, English
    [Refereed]
    Scientific journal

  • Gang Li, Takuya Niimi, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    A high-performance organosilica membrane was prepared via sol-gel processing for use in methylcyclohexane (MCH) dehydrogenation to produce high-purity hydrogen. The membrane showed a high H-2 permeance of 1.29 x 10(-6) mol m(-2) s(-1) Pa-1, with extremely high H-2/C3H8 and H-2/SF6 selectivities of 6680 and 48,900, respectively, at 200 degrees C. The extraction of hydrogen from the membrane reactor led to the MCH conversion higher than the thermodynamic equilibrium, with almost pure hydrogen obtained in the permeate stream without considering the effect of carrier gas and sweep gas in the membrane reactor, and the organosilica membrane reactor was very stable under the reaction conditions employed. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
    PERGAMON-ELSEVIER SCIENCE LTD, Nov. 2013, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 38(35) (35), 15302 - 15306, English
    [Refereed]
    Scientific journal

  • Genghao Gong, Jinhui Wang, Hiroki Nagasawa, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Using 1,2-bis(triethoxysilyl)ethane (BTESE) as the precursor and 1-propanol as the solvent, a uniform and defect-free hybrid organosilica thin coating was successfully deposited onto polysulfone (PSF) film via a sol-gel process using spin coating. The structural characterization, morphology and surface wettability of the BTESE-derived silica coating on PSF film were investigated. Results showed that the outermost layer of the composite film consisted of nanoscale hybrid organosilica networks that were approximately 200 nm in thickness with a low surface roughness. In addition, the measured water contact angle of the composite film decreased from 78.8 degrees to 45.5 degrees, which showed that the surface wettability of the BTESE-coated PSF composite film was also improved. (C) 2013 Elsevier B.V. All rights reserved.
    ELSEVIER, Oct. 2013, MATERIALS LETTERS, 109, 130 - 133, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Takanori Sasaki, Hiromasa Tawarayama, Tomohisa Yoshioka, Toshinori Tsuru
    The sol-gel method was applied to the fabrication of amorphous silica membranes for use in hydrogen separation at high temperatures. The effects of fabrication temperature on the hydrogen permeation properties and the hydrothermal stability of amorphous silica membranes were evaluated. A thin continuous silica separation layer (thickness=<300nm) was successfully formed on the top of a deposited colloidal silica layer in a porous glass support. After heat treatment at 800 degrees C for an amorphous silica membrane fabricated at 550 degrees C, however, it was quite difficult to distinguish the active separation layer from the deposited colloidal silica layer in a porous glass support, due to the adhesion of colloidal silica caused by sintering at high temperatures. The amorphous silica membranes fabricated at 700 degrees C were relatively stable under steam atmosphere (500 degrees C, steam=70kPa), and showed steady He and H2 permeance values of 4.0x10-7 and 1.0x 10-7molm-2s-1Pa-1 with H2/CH4 and H2/H2O permeance ratios of similar to 110 and 22, respectively. The permeance ratios of H2/H2O for membranes fired at 700 degrees C increased drastically over the range of He/H2 permeance ratios by factors of similar to 3-4, and showed a value of similar to 30, which was higher than those fired at 500 degrees C. Less permeation of water vapor through amorphous silica membranes fabricated at high temperatures can be ascribed to the dense amorphous silica structure caused by the condensation reaction of silanol groups.
    WILEY-BLACKWELL, Sep. 2013, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 96(9) (9), 2950 - 2957, English
    [Refereed]
    Scientific journal

  • Gang Li, Kazuya Yada, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    The dehydrogenation of methylcyclohexane (MCH) in catalytic membrane reactors for hydrogen production was studied experimentally and theoretically. The membrane reactor was composed of a Pt/gamma-Al2O3/alpha-Al2O3 catalytic support and a H-2-selective silica separation layer, showing H-2 permeances of (1.51-2.83) x 10(-6) mol m(-2) s(-1) Pa-1 with H-2/SF6 permeance ratios of 290-1000 at 473 K. The MCH conversion was markedly increased after hydrogen extraction from the membrane reactor, which agreed very well with the results obtained by simulation using a proposed mathematical model. The effects of the catalytic activity and hydrogen extraction rate on membrane reactor performance were investigated during the simulations. A system combining a fixed-bed prereactor and a membrane reactor was proposed for MCH dehydrogenation, which further improved the MCH conversion as a result of the enhanced driving force for hydrogen extraction from the membrane reactor.
    AMER CHEMICAL SOC, Sep. 2013, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 52(37) (37), 13325 - 13332, English
    [Refereed]
    Scientific journal

  • Hiroki Nagasawa, Hironobu Shigemoto, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Plasma enhanced chemical vapor deposition (PECVD) was applied to the fabrication of hexamethyldisiloxane (HMDSO) derived amorphous silica membranes. Three different PECVD procedures, namely, Ar-PECVD, O-2-PECVD, and a 2-step PECVD sequence involving Ar-PECVD followed by O-2-PECVD, were employed to determine the effect of carrier gas on membrane structure and gas permeation property. The membrane prepared by Ar-PECVD showed moderate molecular sieving properties at room temperature (permeance ratio of 15 for He/N-2 and 220 for He/SF6), but was easily decomposed at high temperatures. For the case of the O-2-PECVD membrane, the permeance of small molecules such as He and H-2 increased with increasing temperature, while the permeance of large molecules such as N-2 and SF6 was consistent with Knudsen diffusion, and thus the selectivity of He/N-2 increased up to 81 at 500 degrees C. Compared with Ar- and O-2-PECVD, 2-step PECVD membrane showed a excellent molecular sieving properties. Since the 2-step membrane was treated by O-2-PECVD in the second step of the sequence, a good thermal stability was confirmed at temperatures as high as 400 degrees C. The 2-step PECVD membrane showed high He and H-2 permeances of 5.2 x 10(-7) and 2.4 x 10(-7) mol/(m(2) s Pa), respectively, with He/N-2 and H-2/N-2 permeance ratios of 4200 and 1900 at 400 degrees C, respectively. The results suggested that the 2-step PECVD is applicable to the low-temperature fabrication of thermally stable molecular sieving amorphous silica membranes. (C) 2013 Elsevier B.V.. All rights reserved.
    ELSEVIER SCIENCE BV, Aug. 2013, JOURNAL OF MEMBRANE SCIENCE, 441, 45 - 53, English
    [Refereed]
    Scientific journal

  • Jinhui Wang, Genghao Gong, Masakoto Kanezashi, Tomohisa Yoshioka, Kenji Ito, Toshinori Tsuru
    Organic-inorganic hybrid silica membranes were prepared from 1, 2 bis (triethoxysilyl)ethane (BTESE) by sol-gel processing at temperatures as low as 100 degrees C, followed by solid-phase HCl-assisted post-treatment to tune the silica network by reducing the pore size. The Brunauer-Emmett-Teller (BET) surface area, thermogravimetric (TG) and positron annihilation lifetime (PAL) showed reduced pore sizes and a densified network structure of BTESE powder after the HCl-assisted treatment. The HCl-assisted treatment increased the permeance ratios of both He-to-N-2 and He-to-C3H8, while the permeance of He was decreased. During the pervaporation (PV) dehydration of a 90 wt% (wt%) isopropanol (IPA) aqueous solution at 75 degrees C, a BTESE membrane fired at 100 degrees C with HCl treatment showed a stable PV water flux of 2.46 kg m(-2) h(-1) and a separation factor of 3960 for more than 80 h, confirming the successful preparation of BTESE membranes at low firing temperatures. The BTESE-derived silica networks were successfully and easily controlled by this novel HCl-assisted post-treatment. (c) 2013 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Aug. 2013, JOURNAL OF MEMBRANE SCIENCE, 441, 120 - 128, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Daisuke Fuchigami, Tomohisa Yoshioka, Toshinori Tsuru
    The sol-gel method was used to fabricate Pd-SiO2 membranes in which Pd particles 2-30 nm in size were dispersed in a SiO2 layer, and the thickness of the Pd-SiO2 layer was approximately 300 nm. The H-2 permeation properties and the thermal and hydrothermal stabilities of the Pd-SiO2 membranes were evaluated. In the present study, the Pd-SiO2 layer was fabricated by (1) a 1-step method, whereby calcination occurred only at 550 degrees C under a H-2 atmosphere for 1 h, and/or (2) via a 2-step method, whereby a first calcination was administered at 400 degrees C under a H-2 atmosphere for 1 h prior to a second calcination at 550 degrees C under a H-2 atmosphere for 1 h. The Pd-SiO2 membranes were quite stable under a N-2 atmosphere at 500 degrees C, irrespective of the membrane fabrication method (1-step, 2-step calcination). However, under a H-2 atmosphere, the N-2 permeance of a membrane fabricated using the 1-step method increased approximately 10 times after exposure to H-2 for the initial 3 h, and increased with time due to the formation of grain boundaries caused by the aggregation of Pd particles. A Pd-SiO2 membrane fabricated using the 2-step method was relatively stable under a H-2 and steam atmosphere (500 degrees C, steam: 70 kPa), and showed H-2 permeance of 5.0 x 10(-7) mol m(-2) s(-1) Pa-1 with H-2/N-2 and H-2/He permeance ratios of 260 and 2.2, respectively. The experimentally obtained H-2/He permeance ratio for Pd-SiO2 membranes (Si/Pd = 3/1, 317, 218, 119) showed reasonable agreement with a theoretical calculation based on a mixed-matrix structure (continuous phase: SiO2, dispersed phase: Pd). (C) 2013 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Jul. 2013, JOURNAL OF MEMBRANE SCIENCE, 439, 78 - 86, English
    [Refereed]
    Scientific journal

  • Yu Ma, Hye Ryeon Lee, Kaori Okahana, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    The methyl-modified hybrid silica sols with methyltriethoxysilane and tetraethoxysilane were successfully prepared using alkaline (NH3 and tetra-methyl-ammonium hydroxide (TMAH)) and acid catalysts (HCl and CH3COOH) and characterized with thermogravimetric analysis, Fourier transform infra-red, and water contact angle. The methyl-modified silica film showed hydrophobic property with water contact angles over 90 degrees under alkaline or acid catalyst. The methyl-modified silica membranes were fabricated and evaluated with He, H-2, N-2, C3H8, and SF6 at 200 degrees C. He gas permeance for hybrid silica membranes was in the range of 0.61-1.91x10(-6)molm(-2)s(-1)Pa(-1), while He/SF6 and N-2/SF6 permeance ratios of acid-catalyzed membranes was quite higher than those of alkaline catalyzed. Pore size (d(p)) of membranes were evaluated with normalized Knudsen-based permeance method, and the order of pore size for methyl-modified silica membranes can be estimated as follows: HCl-catalyzed membraneTAYLOR & FRANCIS INC, Jul. 2013, DESALINATION AND WATER TREATMENT, 51(25-27) (25-27), 5149 - 5154, English
    [Refereed]
    Scientific journal

  • Takashi Shimoyama, Tomohisa Yoshioka, Hiroki Nagasawa, Masakoto Kanezashi, Toshinori Tsuru
    The virtual structures of organic-inorganic hybrid silica membranes were prepared on a computer by introducing two different types of organic functional groups into a conventional silica network. bis(triethoxysilyl)ethane (BTESE) and bis(triethoxysilyl)ethylene (BTESEthy) derived silica-based organic-inorganic hybrid microporous materials were modeled and their structures such as pore size distribution and radial distribution function were studied. Adsorbability of water and diffusivity of helium molecule was also examined. Both the hybrid silica structures showed larger pore size than pure silica. The difference in water adsorption performance and helium diffusivity was observed between two types of hybrid silica structures. BTESEthy silica showed higher loading of adsorbed water and it is expected to be a promising material for water treatment. Helium diffusivity in BTESEthy silica was greater than that in BTESE silica, which was in consistent with the micropore size.
    DESALINATION PUBL, Jul. 2013, DESALINATION AND WATER TREATMENT, 51(25-27) (25-27), 5248 - 5253, English
    [Refereed]
    Scientific journal

  • Mingming Zhai, Tomohisa Yoshioka, Jianhua Yang, Jinming Lu, Dehong Yin, Jinqu Wang
    Amorphous carbon (a-C) membranes with 1,728 particles were prepared from diamond at four different densities (1.8, 2.0, 2.28, and 2.4g/cm(3)) using molecular dynamics simulation. Stillinger and Weber potential for carbon was introduced with kinetic energy abided by classical Newton equation. Time mesh was chosen 0.01 or 1fs. The melt-quenching technology method was adopted with the corresponding cooling rate 5 and 0.05K/fs, respectively. Different membranes were obtained from higher initial temperature (7,500, 7,000, or 6,500K at different densities and cooling rates) to room temperature. We compared the radial distribution function, bond angle distribution, and pore size distribution with experimental data. The results agreed well and one membrane at lower density with larger pores was chosen to calculate the gas permeation further. Gas molecules (He, Ne, H-2, CO2, N-2, CH4, and SF6) permeation through the a-C membrane at low density (1.8g/cm(3)) when time mesh equal to 1fs were calculated at 300, 400, 473, 500, and 600K. The results of every gas species almost illustrated Knudsen diffusion well. And the number of permeated particles depended on the molecular weight.
    TAYLOR & FRANCIS INC, Jul. 2013, DESALINATION AND WATER TREATMENT, 51(25-27) (25-27), 5231 - 5236, English
    [Refereed]
    Scientific journal

  • Rong Xu, Masakoto Kanezashi, Tomohisa Yoshioka, Tetsuji Okuda, Joji Ohshita, Toshinori Tsuru
    Bis(triethoxysilyl)ethylene (BTESEthy) was used as a novel precursor to develop a microporous organosilica membrane via the sol gel technique. Water sorption measurements confirmed that ethenylene-bridged BTESEthy networks had a higher affinity for water than that of ethane-bridged organosihca materials. High permeance of CO2 with high CO2/N-2 selectivity was explained relative to the strong CO2 adsorption on the network with pi-bond electrons. The introduction of polarizable and rigid ethenylene bridges in the network structure led to improved water permeability and high NaCl rejection (>98.5%) in reverse osmosis (RO). Moreover, the aqueous ozone modification promoted significant improvement in the water permeability of the membrane. After 60 mm of ozone exposure, the water permeability reached 1.1 X 10(-12) m(3)/(m(2) s Pa), which is close to that of a commercial seawater RO membrane. Meanwhile, molecular weight cutoff measurements indicated a gradual increase in the effective pore size with ozone modification, which may present new options for fine-tuning of membrane pore sizes.
    AMER CHEMICAL SOC, Jul. 2013, ACS APPLIED MATERIALS & INTERFACES, 5(13) (13), 6147 - 6154, English
    [Refereed]
    Scientific journal

  • Tomohisa Yoshioka, Masakoto Kanezashi, Toshinori Tsuru
    The effect of the gas molecular size and its affinity to the pore surface on gas permeation properties through the ceramic membranes was studied by both the gas permeation experiments and gas permeation simulations using a nonequilibrium molecular dynamics (MD) technique. A modified gas permeation model equation based on the gas translation (GT) mechanism was presented. MD simulation revealed that the effective diffusion length in a micropore depended on the gas molecular size, and the pre-exponential coefficient of a modified GT model equation showed good correlation with the kinetic diameter of the gas molecules. Also presented is a simple method to estimate the mean pore size of microporous membranes. The estimated pore sizes were consistent with observed kinetic diameter dependencies of gas permeance for real silica membranes. The pore size of a Deca-Dodecasil 3R (DDR) zeolite membrane was also reasonably estimated at approximate to 0.4 nm from the reported gas permeation data. (c) 2012 American Institute of Chemical Engineers AIChE J, 59: 21792194, 2013
    WILEY-BLACKWELL, Jun. 2013, AICHE JOURNAL, 59(6) (6), 2179 - 2194, English
    [Refereed]
    Scientific journal

  • Rong Xu, Jinhui Wang, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Hybrid organosilica membranes were successfully prepared using bis(triethoxysilyl)ethane (BTESE) and applied to reverse osmosis (RO) desalination. The organosilica membrane calcined at 300 degrees C almost completely rejected salts and neutral solutes with low-molecular-weight. Increasing the operating pressure led to an increase in water flux and salt rejection, while the flux and rejection decreased as salt concentration increased. The water permeation mechanism differed from the viscous flow mechanism. Observed activation energies for permeation were larger for membranes with a smaller pore size, and were considerably larger than the activation energy for water viscosity. The organosilica membranes exhibited exceptional hydrothermal stability in temperature cycles up to 90 degrees C. The applicability of the generalized solution-diffusion (SD) model to RO and pervaporation (PV) desalination processes were examined, and the quantitative differences in water permeance were accurately predicted by the application of generalized transport equations. (C) 2012 American Institute of Chemical Engineers AIChE J, 59: 1298-1307, 2013
    WILEY, Apr. 2013, AICHE JOURNAL, 59(4) (4), 1298 - 1307, English
    [Refereed]
    Scientific journal

  • 都留 稔了, 金指 正言, 野村 幹弘, 上宮 成之, 田中 俊輔, 佐藤 公則, 荒木 貞夫, 松方 正彦, 吉岡 朋久
    日本膜学会, 2013, 膜, 38(1) (1), 39 - 49, Japanese

  • Gang Li, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Catalytic decomposition of NH3 with H-2-selective microporous silica membranes for COx-free hydrogen production was studied theoretically and experimentally. The simulation study shows that NH3 conversion, H-2 yield and H-2 purity increase with the Damkohler number (Da), and their improvement is affected by the effect of H-2 extraction as well as NH3 and N-2 permeation through the membranes. The experimental study of NH3 decomposition was carried out in a bimodal catalytic membrane reactor (BCMR), consisting of a bimodal catalytic support and a H-2-selective silica layer. Catalytic membranes showed H-2 permeances of 6.2-9.8 x 10(-7) mol m(-2) s(-1) Pa-1, with H-2/NH3 and H-2/N-2 permeance ratios of 110-200 and 200-700, respectively, at 773 K. The effect of operating conditions on membrane reactor performance with respect to NH3 conversion, H-2 yield and H-2 purity was investigated, and the results were in agreement with those calculated by the proposed simulation model. (C) 2012 American Institute of Chemical Engineers AIChE J, 59: 168-179, 2013
    WILEY, Jan. 2013, AICHE JOURNAL, 59(1) (1), 168 - 179, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Shuji Miyauchi, Hiroki Nagasawa, Tomohisa Yoshioka, Toshinori Tsuru
    The sol-gel method was applied to Al-doped bis (triethoxysilyl) methane (BTESM, Si-C-Si unit) membranes. High C3H6 : C3H8 permeance ratios of approximately 40 at 200 degrees C were achieved through the precise control of the silica network size via a spacer method using Si-C-Si units as well as the incorporation of Al in BTESM-derived networks.
    ROYAL SOC CHEMISTRY, 2013, RSC ADVANCES, 3(30) (30), 12080 - 12083, English
    [Refereed]
    Scientific journal

  • Tomohisa Yoshioka, Hiroki Nagasawa, Masakoto Kanezashi, Toshinori Tsuru
    Molecular dynamics simulation was used to investigate the permeation properties of a virtual condensable vapor through micropores. A permeation model was proposed to simulate the movement of condensable vapor through a micropore. The model is called "micropore filling phase permeation (MFP),"and the effect of feed gas pressure, pore size and pore size distributions on the vapor permeation properties was examined through model calculations. The observed permeance of ethane-like LJ particles at 260 K, a temperature below the critical temperature of real ethane, decreased stepwise at a specific pressure as the mean pressure was increased for micropores sized 0.8 and 1.1 nm in diameter. Analysis of the adsorption isotherm in the pores and vapor permeation simulations revealed the formation of a high-density liquid-like phase in micropores as the MFP caused a decrease in the mobility of permeating molecules. The model calculations based on the MFP showed qualitative agreement with the simulation results.
    SOC CHEMICAL ENG JAPAN, 2013, JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 46(10) (10), 659 - 671, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Toshinobu Shibata, Jinhui Wang, Hye Ryeon Lee, Masakoto Kanezashi, Tomohisa Yoshioka
    Organosilica membranes were prepared from bis(triethoxysilyl)ethane (BTESE) by sol-gel processing and applied to the dehydration of aqueous acetic acid (AcOH) solutions in pervaporation. BTESE-derived membranes were found to show high permselectivity with excellent stability. The permeate flux for aqueous AcOH solutions (AcOH: 90 wt%, 75 degrees C) was 2.0-4.0 kg/(m(2) h) with water selectivity of 200-500, corresponding to water permeance of (2.5-5) x 10(-6) mol/(m(2) s Pa). Long-term stability tests in aqueous AcOH solutions revealed that BTESE membranes showed approximately unchanged flux and separation factors, confirming the excellent stability of organosilica membranes. Comparison with gas permeation properties suggests the separation mechanism is dominated by the molecular sieving effect. Concentration dependency was examined for AcOH concentrations ranging from 30 to 90 mol%. An increase in AcOH concentration decreased both water and AcOH permeance, suggesting that adsorbed AcOH on BTESE membranes reduced the effective pore sizes for permeation of the 2 molecules. (C) 2012 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Dec. 2012, JOURNAL OF MEMBRANE SCIENCE, 421, 25 - 31, English
    [Refereed]
    Scientific journal

  • Jinhui Wang, Genghao Gong, Masakoto Kanezashi, Tomohisa Yoshioka, Kenji Ito, Toshinori Tsuru
    Highly selective organic inorganic hybrid membranes were prepared at low temperature (less than 100 degrees C) from 1,2-bis(triethoxysilyl)ethane (BTESE) with HCl-assisted solid-phase post-treatment, which increased pervaporation dehydration selectivity dramatically from 4 to 2900.
    CHEMICAL SOC JAPAN, Dec. 2012, CHEMISTRY LETTERS, 41(12) (12), 1663 - 1665, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, W. N. Shazwani, Tomohisa Yoshioka, Toshinori Tsuru
    Bis(triethoxysilyl) methane (BTESM), which consists of Si-C-Si bonds, was used as a membrane precursor in the control of amorphous silica network size for separation of C3H6 and C3H8 molecules. Single and binary-component gas permeation/separation characteristics were examined at temperatures ranging from 50 to 200 degrees C for BTESM-derived silica membranes fabricated at various temperatures. Normalized Knudsen-based Permeance (NKP) was applied to evaluate the effect of calcination temperatures on amorphous silica network size. Pore size distribution, as determined by single gas permeation as well as by NKP plotting, suggested that average pore size was successfully tuned by changing the calcination temperatures. BTESM-derived silica membranes showed C3H6 permeance (0.28-6.3 x 10(-7) mol m(-2) s(-1) Pa-1) and a C3H6/C3H8 permeance ratio (6.9-33) at 50 degrees C. For binary-component gas separation at 50 degrees C, preferentially adsorbed C3H6 molecules could efficiently block the permeation of C3H8 molecules, resulting in C3H6/C3H8 permeance ratios that were higher than those obtained by single-gas permeation. The ratios of alpha (separation)/alpha (ideal) for BTESM-derived membranes fired at 200 degrees C were higher than those for membranes fired at 350 degrees C, due to the higher density of silanol groups, that can interact with the pi-bond (C=C double bond) of C3H6 molecules. (c) 2012 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Oct. 2012, JOURNAL OF MEMBRANE SCIENCE, 415, 478 - 485, English
    [Refereed]
    Scientific journal

  • Jinhui Wang, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Organic-inorganic hybrid membranes from 1,2-bis (triethoxysilyl)ethane (BTESE) were prepared by sol-gel processing, and we examined the effects of firing temperatures ranging from 100 to 300 degrees C on membrane separation performance. The contact angle, thermogravimetric (TG) and infrared (IR) spectrum showed that the structure of the membrane changed with top-layer firing temperatures. BTESE-100, prepared by firing at 100 degrees C, showed an He permeance of 2.2 x 10(-7) mol/(m(2) s Pa) with a He/SF6 separation factor of about 140, while BTESE-300, prepared by firing at 300 degrees C, showed a He/SF6 of about 3000 with an He permeance of 1.5 x 10(-6) mol/(m(2) s Pa). In pervaporation (PV) dehydration of a 90 wt% isopropanol (IPA) aqueous solution at 75 degrees C, BTESE-100 and BTESE-300 showed water fluxes of 2.51 and 3.40 kg/(m(2) h) with separation factors of 130 and 4370, respectively. Moreover, BTESE-100 showed a stable PV flux and separation factor for more than 10 h, confirming the successful preparation of BTESE membranes at low firing temperatures. (c) 2012 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Oct. 2012, JOURNAL OF MEMBRANE SCIENCE, 415, 810 - 815, English
    [Refereed]
    Scientific journal

  • Gang Li, Masakoto Kanezashi, Hye Ryeon Lee, Makoto Maeda, Tomohisa Yoshioka, Toshinori Tsuru
    A novel bimodal catalytic membrane reactor (BCMR) consisting of a Ru/gamma-Al2O3/alpha-Al2O3 bimodal catalytic support and a silica separation layer was proposed. The catalytic activity of the support was successfully improved due to enhanced Ru dispersion by the increased specific surface area for the gamma-Al2O3/alpha-Al2O3 bimodal structure. The silica separation layer was prepared via a sol-gel process, showing a H-2 permeance of 2.6 x 10(-7) mol Pa-1 m(-2) s(-1), with H-2/NH3 and H-2/N-2 permeance ratios of 120 and 180 at 500 degrees C. The BCMR was applied to NH3 decomposition for COx-free hydrogen production. When the reaction was carried out with a NH3 feed flow rate of 40 ml min(-1) at 450 degrees C and the reaction pressure was increased from 0.1 to 0.3 MPa, NH3 conversion decreased from 50.8 to 35.5% without H-2 extraction mainly due to the increased H-2 inhibition effect. With H-2 extraction, however, NH3 conversion increased from 68.8 to 74.4% due to the enhanced driving force for H-2 permeation through the membrane. Copyright (C) 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
    PERGAMON-ELSEVIER SCIENCE LTD, Sep. 2012, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, 37(17) (17), 12105 - 12113, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Mitsuki Kawano, Tomohisa Yoshioka, Toshinori Tsuru
    Bis(triethoxysilyl)methane (BTESM), which consists of Si-C-Si bonds, was used as a membrane precursor to control the size of amorphous silica networks. The single gas permeation characteristics of hybrid silica membranes were examined to determine the effect of silica precursors on amorphous networks. Pore size distribution, as determined by single gas permeation, suggested that average pore size was in the following order: bis(triethoxysilyl)ethane (BTESE)-derived silica > BTESM-derived silica > tetraethoxysilane (TEOS)-derived silica, due to differences in the minimum units of the silica precursor. The high C3H6/C3H8 separation performance of BTESM-derived silica membranes in a wide temperature range (50-200 degrees C) can be due to the control of silica network size by the "spacer" method using a Si-C-Si unit. For example, a BTESM-derived silica membrane showed a high C3H6 permeance of 6.32 x 10(-7) mol m(-2) s(-1) Pa-1 with a C3H6/C3H8 permeance ratio of 8.8 at 50 degrees C. The order of C3H6 and C3H8 permeances of BTESM-derived silica membranes was C3H6 > C3H8, independent of the number of sol coats and temperature (50-200 degrees C), although the kinetic diameter of C3H6 (d(k) = 0.45 nm) was reported to be larger than that of C3H8 (d(k) = 0.43 nm). For permeation of hydrocarbons through amorphous silica membranes, it is suggested that the kinetic diameter, which is a minimum equilibrium cross-sectional diameter, is not applicable for effective molecular size, probably because diffusivity depends not only on the minimum cross section but also on molecular length.
    AMER CHEMICAL SOC, Jan. 2012, INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH, 51(2) (2), 944 - 953, English
    [Refereed]
    Scientific journal

  • Rong Xu, Jinhui Wang, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Hybrid organically bridged silica membranes have attracted considerable attention because of their high performances in a variety of applications. Development of robust reverse osmosis (RO) membranes to withstand aggressive operating conditions is still a major challenge. Here, a new type of microporous organosilica membrane has been developed and applied in reverse osmosis. Sol-gel derived organosilica RO membranes reject isopropanol with rejection higher than 95%, demonstrating superior molecular sieving ability for neutral solutes of low molecular weight. Due to the introduction of an inherently stable hybrid network structure, the membrane withstands higher temperatures in comparison with commercial polyamide RO membranes, and is resistant to water to at least 90 degrees C with no obvious changes in filtration performance. Furthermore, both an accelerated chlorine-resistance test and Fourier transform infrared analysis confirm excellent chlorine stability in this material, which demonstrates promise for a new generation of chlorine-resistant RO membrane materials.
    AMER CHEMICAL SOC, Dec. 2011, LANGMUIR, 27(23) (23), 13996 - 13999, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Takehiro Nakasuji, Minami Oka, Masakoto Kanezashi, Tomohisa Yoshioka
    Methylated SiO2 colloidal sol solutions were prepared by hydrolysis and condensation reactions of mixed tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES) using EtOH as a solvent with NH3 as a catalyst. Organic/inorganic hybrid membranes were prepared by coating porous substrates with the methylated SiO2 solutions and calcinating at 400-600 degrees C in an N-2 atmosphere. Nanopermporometry characterization using water and hexane as a condensable vapor confirmed the successful preparation of hydrophobic nano-sized pores of 2-4 nm (hexane-based). The hexane permeability of methylated SiO2 membranes was almost constant following the addition of water in concentrations of 0-80 ppm (saturated), but the permeability of hydrophilic TiO2 membranes was decreased by the addition of water. Methylated SiO2 membranes were applied for the nanofiltration of polyolefin oligomers in hexane solutions. The hexane permeability of polyolefin oligomers/hexane solutions was approximately the same as that of pure hexane, which suggested there was no fouling of the hydrophobic SiO2 membranes and hexane solutions. Methylated SiO2 membranes showed a hexane permeability of 2.0-7.58 x 10(-11) m(3)/(m(2) s Pa), which corresponds to 7.2 and 27 L/(m(2) h bar), with molecular weight cut-offs of 1000-2000. (C) 2011 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Nov. 2011, JOURNAL OF MEMBRANE SCIENCE, 384(1-2) (1-2), 149 - 156, English
    [Refereed]
    Scientific journal

  • Hye Ryeon Lee, Masakoto Kanezashi, Yoshihiro Shimomura, Tomohisa Yoshioka, Toshinori Tsuru
    Organic/inorganic hybrid silica membranes were prepared from 1,1,3,3-tetraethoxy-1,3-dimethyl disiloxane (TEDMDS) by the sol-gel technique firing at 300-550 degrees C in N-2. TEDMDS-derived silica membranes showed high H-2 permeance (0.3-1.1 x 10(-6) mol m(-2) s(-1) Pa-1) with low H-2/N-2 (similar to 10) and high H-2/SF6 (similar to 1200) perm-selectivity, confirming successful tuning of micropore sizes larger than TEOS-derived silica membranes. TEDMDS-derived silica membranes prepared at 550 degrees C in N-2 increased gas permeances as well as pore sizes after air exposure at 450 degrees C. TEDMDS had an advantage in tuning pore size by the "template" and "spacer" techniques, due to the pyrolysis of methyl groups in air and Si-O-Si bonding, respectively. For pore size evaluation of microporous membranes, normalized Knudsen-based permeance, which was proposed based on the gas translation model and verified with permeance of zeolite membranes, reveals that pore sizes of TEDMDS membranes were successfully tuned in the range of 0.6-1.0 nm. (C) 2011 American Institute of Chemical Engineers AIChE J, 57: 2755-2765, 2011
    WILEY, Oct. 2011, AICHE JOURNAL, 57(10) (10), 2755 - 2765, English
    [Refereed]
    Scientific journal

  • Kai-Shiun Chang, Tomohisa Yoshioka, Masakoto Kanezashi, Toshinori Tsuru, Kuo-Lun Tung
    A molecular dynamics (MD) technique using h-pcff force field was adopted to analyze the micro-structure and gas transport behavior of an organic-inorganic hybrid bis(triethoxysilyl)ethane (BTESE) silica membrane. The membrane fractional free space (FFS), cavity size distribution (CSD), and fractional accessible volume (FAV) were estimated to discuss how doped Si-C-C-Si segments affect a silica network. The radial distribution function (RDF) of atom pairs was analyzed to investigate the micro-structure of a hybrid silica network. The gas diffusion behavior, including the thermal motion and diffusivity, was calculated to understand the gas transport behavior of the BTESE silica membrane. The analyses of the FFS, CSD, and FAV of the silica membrane indicated that the silica network would expand to form a larger cavity size, indicating a high potential for increased gas permeance. The RDF diagram indicates that the hybrid silica matrix provides a looser structure with higher network fluctuation than that of the pure silica membrane. The gas diffusion behavior analysis revealed that the hybrid silica membrane contained more effective free space, which prompted H(2) diffusivity and also produced a good H(2)/SF(6) diffusivity ratio. The MD technique was successfully applied to simulate the characteristics and gas diffusion behaviors of the hybrid BTESE silica membrane. Demonstration of the superior properties of hybrid BTESE silica using MD technique proves itself to be a promising tool for material development and design on a microscopic view. (C) 2011 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Sep. 2011, JOURNAL OF MEMBRANE SCIENCE, 381(1-2) (1-2), 90 - 101, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Akifumi Sasaki, Masakoto Kanezashi, Tomohisa Yoshioka
    Porous silica membranes with different pore sizes (average pore size: 0.3-1.2 nm) and surface chemistry were prepared from SiO2, steam-treated SiO2, SiO2 AZrO(2), and SiO2-ATiO(2) by sol-gel processing, and were applied to the pervaporation (PV) separation of methanol (MeOH) /dimethyl carbonate (DMC) mixtures at 50 degrees C. Although SiO2 AZrO(2) membranes demonstrated a separation factor of <10, the SiO2 porous membranes had an increased separation factor from 10-160. Silica membranes with an average pore size of 0.3 nm showed the highest permselectivity of methanol with a separation factor of 140 and a methanol flux of 180 mol/(m(2)h) for MeOH 50 mol% at 50 degrees C. To characterize the surface property of SiO2 membranes, SiO2 powdered samples were used for an adsorption experiment of vapor (MeOH, DMC) in single and mixed systems, revealing increased MeOH selective adsorption for SiO2 powders with hydrophilic and small pores, which was consistent with PV performance. (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 2079-2089, 2011
    WILEY, Aug. 2011, AICHE JOURNAL, 57(8) (8), 2079 - 2089, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Ryousuke Igi, Masakoto Kanezashi, Tomohisa Yoshioka, Shinji Fujisaki, Yuji Iwamoto
    Silica and cobalt-doped silica membranes that showed a high permeance of 1.8 X 10(-7) mol m(-2) s(-1) Pa(-1) and a H(2)/N(2) permeance ratio of similar to 730, with excellent hydrothermal stability under steam pressure of 300 kPa, were successfully prepared. The permeation mechanism of gas molecules, focusing particularly on hydrogen and water vapor, was investigated in the 300-500 degrees C range and is discussed based on the activation energy of permeation and the selectivity of gaseous molecules. The activation energy of H(2) permeation correlated well with the permeance ratio of He/H(2) for porous silica membranes prepared by sol-gel processing, chemical vapor deposition (CVD), and vitreous glasses, indicating that similar amorphous silica network structures were formed. The permeance ratios of H(2)/H(2)O were found to range from 5 to 40, that is, hydrogen (kinetic diameter: 0.289 nm) was always more permeable than water (0.265 nm). (C) 2010 American Institute of Chemical Engineers AIChE J, 57: 618-629, 2011
    WILEY-BLACKWELL, Mar. 2011, AICHE JOURNAL, 57(3) (3), 618 - 629, English
    [Refereed]
    Scientific journal

  • Chunlong Kong, Akira Koushima, Takashi Kamada, Takuji Shintani, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    A promising strategy is reported for the synthesis of inorganic-polyamide nanocomposite membranes on an ultrafiltration polysulfone support via metal-alkoxide-assisted interfacial polymerization. Three types of nanocomposite membranes were prepared using three different metal alkoxides. The metal alkoxides used here were titanium tetraisopropoxide, bis(triethoxysilyl)ethane and phenyltriethoxysilane. The as-prepared nanocomposite membranes exhibited performance superior to that of the pure polyamide membrane. Water flux and salt rejection were observed for each of the nanocomposite membranes. Addition of greater amounts of metal alkoxide to the hexane solution increased both pore size and water flux, which were determined by analysis of the membrane permeation data using aqueous solutions of sodium chloride and organic solutes at a pressure of 1.5 MPa and a temperature of 25 degrees C. The best nanocomposite membrane that was prepared with phenyltriethoxysilane showed water flux that was increased approximately 2-fold compared with the pure polyamide membrane with negligible rejection loss. (C) 2010 Elsevier B.V. All rights reserved.
    ELSEVIER, Jan. 2011, JOURNAL OF MEMBRANE SCIENCE, 366(1-2) (1-2), 382 - 388, English
    [Refereed]
    Scientific journal

  • Clara Casado Coterillo, Tsuyoshi Yokoo, Tomohisa Yoshioka, Toshinori Tsuru, Masashi Asaeda
    The development of gas separation membranes able to work at high temperatures require robust and thin ceramic layers. In this work, zirconia membranes have been prepared by the sol-gel method, following the colloidal sol route. The microporosity and crystallinity of the ZrO2 material was tested by N2 adsorption and XRD. The derived active zirconia layers were defect-free as seen by SEM. The optimum firing temperature range was set in the range 400-500 degrees C. He, H2, CO2, N2 gas permeation was conducted at temperatures up to 200 degrees C. High permeances were obtained and the microporosity of the zirconia layer was confirmed.
    TAYLOR & FRANCIS INC, 2011, SEPARATION SCIENCE AND TECHNOLOGY, 46(8) (8), 1224 - 1230, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Hironobu Shigemoto, Masakoto Kanezashi, Tomohisa Yoshioka
    Amorphous SiO2 membranes were prepared via a 2-step plasma-enhanced CVD (PECVD) technique at room temperature on porous TiO2/Al2O3 substrates. SiO2 membranes showed molecular sieving properties with a high separation factor for He/N-2 and He/H-2, and high thermal stability, indicating the successful preparation of high-performance membranes at low temperatures.
    ROYAL SOC CHEMISTRY, 2011, CHEMICAL COMMUNICATIONS, 47(28) (28), 8070 - 8072, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Kazuhisa Ogawa, Masakoto Kanezashi, Tomohisa Yoshioka
    Nanoporous Mania membranes with controlled pore sizes ranging from 0.7 to 2.5 nm, which had molecular weight cutoffs (MWCO) ranging from 500 to 2000, were successfully prepared by sol-gel processing, and the transport characteristics were evaluated across a temperature range of 30-80 degrees C. With increasing temperature, the permeate flux increased 2- to 3-fold, depending on the pore size. The water permeation mechanism was found to be different from viscous flow and was explained by the state of the water (free water/bound water/nonfreezing water) inside confined pores. The rejection of neutral solutes such as raffinose, the separation mechanism of which is molecular sieving (steric hindrance), decreased with temperature whereas that of electrolytes (MgCl2 and NaCl), the separation mechanism of which is the charge effect (Donnan exclusion), was approximately constant. The temperature dependence of neutral and electrolyte solutes was analyzed using the Spiegler-Kedem equation by combining the Arrhenius equations for diffusivity and viscosity, which we obtained Delta E-m the activation energy of diffusion, after eliminating the effect of viscosity. For large Delta E-m, which corresponds to the rejection of neutral solutes on the basis of molecular sieving, rejection decreased with temperature but remained unchanged for small Delta E-m, which corresponds to the rejection of electrolytes based on the charge effect.
    AMER CHEMICAL SOC, Jul. 2010, LANGMUIR, 26(13) (13), 10897 - 10905, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Akira Yamamoto, Tomohisa Yoshioka, Toshinori Tsuru
    A sol-gel method was applied for the preparation of silica membranes with different average pore sizes. Ammonia (NH3) permeation/separation characteristics of the silica membranes were examined in a wide temperature range (50-400 degrees C) by measurement of both single and binary component separation. The order of gas permeance through the silica membranes, which was independent of membrane average pore size, was as follows: He > H-2 > NH3 > N-2. These results suggest that, for permeation through silica membranes, the molecular size of NH3 is larger than that of H-2, despite previous reports that the kinetic diameter of NH3 is smaller than that of H-2. At high temperatures, there was no effect of NH3 adsorption on H-2 permeation characteristics, and silica membranes were highly stable in NH3 at 400 degrees C (i.e., gas permeance remained unchanged). On the other hand, at 50 degrees C NH3 molecules adsorbed on the silica improved NH3-permselectivity by blocking permeation of H-2 molecules without decreasing NH3 permeance. The maximal NH3/H-2 permeance ratio obtained during binary component separation was similar to 30 with an NH3 permeance of similar to 10(-7) mol m(-2) s(-1) Pa-1 at an H-2 permeation activation energy of similar to 6 kJ mol(-1). (C) 2009 American Institute of Chemical Engineers AIChE J, 56: 1204-1212, 2010
    WILEY, May 2010, AICHE JOURNAL, 56(5) (5), 1204 - 1212, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Hideto Matsuyama, Mitsuru Higa, Tomohisa Yoshioka
    DESALINATION PUBL, May 2010, DESALINATION AND WATER TREATMENT, 17(1-3) (1-3), 1 - 1, English
    [Refereed]

  • Jinhui Wang, Tomohisa Yoshioka, Masakoto Kanezashi, Toshinori Tsuru
    In this study, pervaporation (PV) performance of porous silica membranes during dehydration of ethanol aqueous solutions was correlated with single gas permeation data in an attempt to predict PV performance. Porous silica membranes were prepared using a sol-gel technique with silica or cobalt-doped silica sols fired at different temperatures (from 350 degrees C to 550 degrees C) in air. Single gas permeation experiments were performed using pure gases (He, N(2), CO(2) and SF(6)) at 200 degrees C just after membrane preparation. PV experiments were carried out at 70 degrees C at an ethanol feed concentration of 94 wt%. The time-course of PV performance and temperature-dependence for a single gas were investigated. The reproducibility of PV separation and gas permeation was investigated and confirmed. An attempt was made to find correlations between single gas permeation experimental data and PV separation performance. The permeance of He was reasonably well correlated with PV water flux. The permeance ratio of He/SF(6) was correlated with the PV separation factor.
    DESALINATION PUBL, May 2010, DESALINATION AND WATER TREATMENT, 17(1-3) (1-3), 106 - 112, English
    [Refereed]
    Scientific journal

  • Hye Ryeon Lee, Masakoto Kanezashi, Tomohisa Yoshioka, Toshinori Tsuru
    Hybrid silica membranes were prepared using 1,1,3,3-tetraethoxy-1,3-dimethyldisiloxane (TEDMDS) as a silica precursor. Hybrid silica sol was synthesized by the acetic acid catalyzed hydrolysis and condensation of TEDMDS in ethanol as a solvent with different water molar ratio. Porous silica membranes were fabricated by coating the TEDMDS-derived hybrid silica sol, followed by drying and firing at 300 degrees C or 450 degrees C in nitrogen atmosphere. Single gas permeation characteristic of He, H-2, N-2, and SF6 through TEDMDS-derived silica membranes were measured at 200 degrees C. It was found that TEDMDS-derived silica membranes had loose amorphous structure than TEOS-derived silica membranes. TEDMDS-derived silica membrane fired at 300 degrees C using TEDMDS/H2O = 1/20 sol showed H-2 permeance of 2.05 x 10(-6) m(3) m(-2) s(-1) kPa(-1) with H-2/SF6 selectivity of 260 degrees C at 200 degrees C. The water contact angles of TEDMDS-derived silica film were constant even after kept in humid atmosphere (60 RH%, 40 degrees C) for about 35 d, suggesting a hydrophobic property due to the presence of CH3 groups.
    DESALINATION PUBL, May 2010, DESALINATION AND WATER TREATMENT, 17(1-3) (1-3), 120 - 126, English
    [Refereed]
    Scientific journal

  • Sol-gel derived organic-inorganic silica membranes with controlled silica network size
    Masakoto Kanezashi, Kazuya Yada, Tomohisa Yoshioka, Toshinori Tsuru
    AMER CHEMICAL SOC, Mar. 2010, ABSTRACTS OF PAPERS OF THE AMERICAN CHEMICAL SOCIETY, 239, English
    [Refereed]

  • Masakoto Kanezashi, Kazuya Yada, Tomohisa Yoshioka, Toshinori Tsuru
    Bis(triethoxysilyl) ethane (BTESE), which consists of Si-C-C-Si bonds, was used as a silica precursor to prepare organic-inorganic hybrid silica membranes with loose amorphous networks. Single-gas permeation and binary-component gas separation characteristics for hybrid silica membranes were examined to discuss the effect of silica precursors on amorphous networks. The pore size distribution, as determined by single-gas permeation, suggested BTESE-derived silica membranes have loose amorphous structures compared to TEOS-derived silica membranes due to the differences in the minimum units of silica networks. For example, BTESE-derived silica membranes showed a high hydrogen permeance (0.2-1 x 10(-5) Mol m(-2) s(-1) Pa(-1)) with a high selectivity of H(2) to SF(6) (H(2)/SF(6) permselectivity: 1000-25,500) and a low H(2) to N(2) permselectivity (similar to 20). The binary-component gas separation of He and SF(6) for a BTESE-derived silica membrane revealed that the swelling effect (adsorption-induced expansion of the zeolite crystals) by SF(6) molecules, which has been suggested for zeolite membranes, was not observed in amorphous silica networks. In the present study, BTESE-derived silica membranes had high hydrothermal stability due to the presence of Si-C-C-Si bonds in the amorphous silica network. (C) 2009 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Feb. 2010, JOURNAL OF MEMBRANE SCIENCE, 348(1-2) (1-2), 310 - 318, English
    [Refereed]
    Scientific journal

  • Li Gang, Kanezashi Masakoto, Yoshioka Tomohisa, Tsuru Toshinori
    The Society of Chemical Engineers, Japan, 2010, 化学工学会 研究発表講演要旨集, 2010, 935 - 935

  • Tsuru T, Matsuyama H, Higa M, Yoshioka T
    2010, Desalination and Water Treatment, 17(1-3) (1-3), 1
    [Refereed]

  • DESIGN OF SILICA NETWORKS USING ORGANIC-INORGANIC HYBRID ALKOXIDES FOR HIGHLY PERMEABLE HYDROGEN SEPARATION MEMBRANES
    Masakoto Kanezashi, Kazuya Yada, Tomohisa Yoshioka, Toshinori Tsuru
    Sol-gel method was applied for the preparation of organic-inorganic hybrid silica membranes. 1,3,5,7-tetramethylcyclotetrasiloxane (TMCTS) and bis (triethoxysilyl) ethane (BTESE) were used as silica precursors instead of tetraethoxysilane (TEOS) for the preparation of organic-inorganic hybrid silica membranes. Molecular weight of hybrid silica polymer was successfully controlled by reaction time and reaction temperature. Single gas permeation characteristics for hybrid silica membranes were examined to discuss the effect of silica precursor on amorphous silica networks. Pore size distribution suggested hybrid silica membranes derived by BTESE and TMCTS had loose amorphous silica structures compared to silica membranes derived by TEOS. Hybrid silica membranes derived by BTESE and TMCTS showed high hydrogen permeance (0.3-1 x 10(-5) mol.m(-2).s(-1).Pa(-1)) with high selectivity of H(2) to SF(6) (H(2)/SF(6) permselectivity: similar to 1,000) and low H(2) to N(2) permselectivity (similar to 10). It was found that hybrid silica membrane derived by TMCTS had high hydrothermal stability due to the presence of CH(3) groups in amorphous silica networks.
    AMER CERAMIC SOC, 2010, ADVANCES IN BIOCERAMICS AND POROUS CERAMICS II, 30(6) (6), 229 - 239, English
    [Refereed]
    International conference proceedings

  • Akihiro Nakata, Tomohisa Yoshioka, Masakoto Kanezashi, Toshinori Tsuru
    Pore structures of microporous silica membranes, and the relationship between membrane structural characteristics and gas permeation properties were studied by molecular dynamics (MD) simulation. Virtual SiO(2) membranes were prepared by the melt-quench procedure utilizing Born-Mayer-Huggines (BMH) pair potential and Stillinger-Weber (SW) three-body interactions. In this study, two types of virtual SiO(2) membrane models were prepared: a network pore model formed by silica polymers; and a bimodal pore model consisting of network pores and penetrating pores, which simulated an inter-particle pore. Gas permeation simulations were conducted using a dual control plane non-equilibrium molecular dynamics (DCP-NEMD) method. Helium and CO(2) were adopted as permeating gas species, and their permeabilities were calculated at temperatures from 300 to 800 K. In the case of the network model, permeation of CO(2) could not be observed, and helium permeation characteristics were in good agreement with experimental data. These results showed the qualitative validity of the network pore model prepared in this study. In the case of bimodal pore model, permeation of CO(2) could be observed, so this result indicated the existence of an inter-particle pore effect on gas permeation properties. In addition, CO(2) permeation characteristics were in agreement with experimental data, thus indicating the qualitative validity of the network pore model and penetrating pore model.However, the simulated permeabilities of helium and CO(2) by the bimodal pore model were larger than those previously reported for actual silica membranes. The bimodal pore model prepared in this study underestimates the ratio of network pore area per inter-particle pore, since the simulated permeability of each gas through the bimodal pore model could be approximated to experimental data by increasing the ratio of network pore area per inter-particle pore. Optimization of the virtual silica membrane area showed that one inter-particle pore existed per square with side length of about 8-11.5 nm. Such a valuable finding about the microstructure of a silica membrane as the ratio of "network pore area/inter-particle pore" could be obtained by using molecular dynamics simulation.
    SOC CHEMICAL ENG JAPAN, 2010, KAGAKU KOGAKU RONBUNSHU, 36(3) (3), 174 - 180, Japanese
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Chie Shimada, Mitsunori Sano, Tomohisa Yoshioka, Toshinori Tsuru
    A sol-gel method was applied for the preparation of palladium-doped silica membranes for hydrogen separation. Hydrogen permeation performance and stability (thermal, hydrothermal) were evaluated by measuring the time and temperature dependence of gas permeances (N(2), H(2) , He) in N(2) and steam atmospheres (steam: 70 kPa) at 500 degrees C, respectively. It was found that the Pd-doped silica layer has a thickness of approximately 80 nm, and Pd particles of several nanometers were well dispersed in an amorphous silica matrix. Pd-doped silica membranes (Si/Pd=3/1) fired at 550 degrees C in air were quite stable in N(2) atmosphere at 500 degrees C, but a drastic decrease of gas permeances (He, H(2), N(2)) and an increase of activation energy of gas permeation (He, H(2)) were observed under H(2) atmosphere at 500 degrees C due to aggregation of Pd particles. Pd-doped silica membranes (Si/Pd=3/1) fired at 550 degrees C in H(2) showed high stability in hydrogen and steam atmospheres (steam: 70 kPa) at 500 degrees C. This is because well-dispersed Pd particles in amorphous silica networks could not move in hydrogen and steam atmospheres.
    SOC CHEMICAL ENG JAPAN, 2010, KAGAKU KOGAKU RONBUNSHU, 36(5) (5), 472 - 479, Japanese
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Mitsunori Sano, Tomohisa Yoshioka, Toshinori Tsuru
    Pd-silica mixed-matrix membranes with superior H(2) permeability and hydrothermal stability at high temperatures were successfully fabricated using a sol-gel method. The Pd-silica layer was quite thin (100-200 nm) and small Pd particles (several nm) dispersed well in an amorphous silica matrix.
    ROYAL SOC CHEMISTRY, 2010, CHEMICAL COMMUNICATIONS, 46(33) (33), 6171 - 6173, English
    [Refereed]
    Scientific journal

  • Kai-Shiun Chang, Tomohisa Yoshioka, Masakoto Kanezashi, Toshinori Tsuru, Kuo-Lun Tung
    A new molecular dynamics simulation method was successfully applied to construct a homogeneous organic-inorganic hybrid silica membrane using the hybrid-pcff (h-pcff) potential function. Analysis suggested that the hybrid BTESE silica membrane provided a looser network and larger cavity size for the enhancement of gas permeability and selectivity.
    ROYAL SOC CHEMISTRY, 2010, CHEMICAL COMMUNICATIONS, 46(48) (48), 9140 - 9142, English
    [Refereed]
    Scientific journal

  • Masakoto Kanezashi, Kazuya Yada, Tomohisa Yoshioka, Toshinori Tsuru
    A sol-gel method was applied for the development of highly permeable hydrogen separation membranes using bis(triethoxysilyl)ethane (BTESE) as a silica precursor. Hybrid silica membranes showed quite high hydrogen permeance (1 x 10(-5) mol m(-2) s(-1) Pa-1) with a high H-2-to-SF6 selectivity of 1000 because of loose organic-inorganic silica networks. Hybrid silica membranes were found to show high hydrothermal. stability due to the presence of Si-C-C-Si bonds in silica networks.
    AMER CHEMICAL SOC, Jan. 2009, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 131(2) (2), 414 - +, English
    [Refereed]
    Scientific journal

  • T. Tsuru, M. Narita, R. Shinagawa, T. Yoshioka
    Nanoporous titania membranes, with pore sizes ranging from I to several nm, were prepared by sol-gel processing and applied to permeation of hexane as a model nonaqueous solution system. TiO(2) membranes showed a deceased hexane flux with an increase in water concentration, which was dissolved in hexane from zero to several hundred ppm. Nanopermporometry characterization before and after hexane permeation showed no change in pore structures of TiO(2) membranes. Therefore, it was suggested that the dissolved water adsorbed to the hydrophilic TiO(2) surface and reduced the effective pore size for hexane permeation. Negative rejection was observed in nanofiltration of linoleic acid in hexane solutions, that is, the linoleic acid was concentrated in permeate. Negative rejection was enhanced with decreasing pore diameter.
    ELSEVIER SCIENCE BV, Dec. 2008, DESALINATION, 233(1-3) (1-3), 1 - 9, English
    [Refereed]
    Scientific journal

  • Tomohisa Yoshioka, Akinori Yasumoto, Kouhei Kishi, Toshinori Tsuru
    Imaginary amorphous silica membranes were prepared on a computer and gas permeation simulations were conducted using a dual control plane non-equilibrium molecular dynamics (DCP-NEMD) method. The Melt-Quench technique was employed to prepare vanous types of imaginary amorphous silica membranes which had different densities (from 1.3 to 2.2 g/cm(3)) and different mean pore sizes. Helium was adopted as a permeating gas species and its permeability was calculated at temperatures from 300 to 800 K. The Knudsen diffusion-like temperature dependencies of permeability could be observed for densities below 1.7 g/cm(3), while the activated diffusion for the higher density models. We have also examined the effect of 3-body membrane potential parameters on membrane dynamics and gas permeation properties. The larger thermal vibration of oxygen atoms both in siloxane bonds and silanol groups on membranes could be observed for greater gamma(1) parameter in the SW potential function, which might result in the change of activation energy for gas permeation.
    ELSEVIER SCIENCE BV, Dec. 2008, DESALINATION, 233(1-3) (1-3), 333 - 341, English
    [Refereed]
    Scientific journal

  • Ryosuke Igi, Tomohisa Yoshioka, Yumi H. Ikuhara, Yuji Iwamoto, Toshinori Tsuru
    Co-doped silica sol solutions with varying Co composition (Co/(Si+Co)=10-50 mol%) were prepared from tetraethoxysilane and Co(NO(3))(2).6H(2)O. Subsequently, these solutions were used in the preparation of hydrogen separation microporous membranes with enhanced hydrothermal stability at 500 degrees C under a steam pressure of 300 kPa. At Co concentrations > 33%, the XRD pattern and peak intensity of the Co-doped silica preparations were similar and were not dependent on Co composition, suggesting that Co was incorporated into the silica network. The best H(2) permeation performance in a steam atmosphere (500 degrees C; steam pressure, 300 kPa) was obtained using silica doped with approximately 30 mol% Co. Co-doped silica membranes (Co 33 mol%) fired at 600 degrees C under a steam partial pressure of 90 kPa showed stable gaseous permeances and a H(2) permeance of approximately 2.00-4.00 x 10(-6) m(3)(STP).(m.s.kPa)(-1) with a selectivity of 250-730 (H(2)/N(2)), even after 60 h of exposure to steam (steam pressure, 300 kPa) at 500 degrees C.
    WILEY-BLACKWELL, Sep. 2008, JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 91(9) (9), 2975 - 2981, English
    [Refereed]
    Scientific journal

  • T. Tsuru, T. Morita, H. Shintani, T. Yoshioka, M. Asaeda
    Hydrogen production by steam reforming of methane using catalytic membrane reactors was investigated first by simulation, then by experimentation. The membrane reactor simulation, using an isothermal and plug-flow model with selective permeation from reactant stream to permeate stream, was conducted to evaluate the effect of permselectivity on membrane reactor performance - such as methane conversion and hydrogen yield - at pressures as high as 1000 kPa. The simulation study, with a target for methane conversion of 0.8, showed that hydrogen yield and production rate have approximately the same dependency on operating conditions, such as reaction pressure, if the permeance ratio of hydrogen over nitrogen (alpha(H-2/N-2)) is larger than 100 and of H-2 over H2O is larger than 15. Catalytic membrane reactors, consisting of a microporous Ni-doped SiO2 top layer and a catalytic support, were prepared and applied experimentally for steam reforming of methane at 500 degrees C. A bimodal catalytic support, which allows large diffusivity and high dispersion of the metal catalyst, was prepared for the enhancement of membrane catalytic activity. Catalytic membranes having H-2 permeances in the range of 2-5 x 10(-6) m(3) m(-2) s(-1) kPa(-1), with H-2/N-2 of 25-500 and H-2/H2O of 6-15, were examined for steam reforming of methane. Increased performance for the production of hydrogen was experimentally obtained with an increase in reaction-side pressure (as high as 500 kPa), which agreed with the theoretical simulation with no fitting parameters. (C) 2007 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, May 2008, JOURNAL OF MEMBRANE SCIENCE, 316(1-2) (1-2), 53 - 62, English
    [Refereed]
    Scientific journal

  • Tomohisa Yoshioka, Masashi Asaeda, Toshinori Tsuru
    The mechanisms involved in pressure-driven gas permeation through a micropore on vitreous SiO2 membranes were examined molecular dynamics (MD) simulation. Virtual amorphous SiO2 membranes were prepared by the melt-quench method utilizing modified Born-Mayer-Huggins (BMH) pair potential and Stillinger-Weber (SW) three-body interactions. A dual control plane non-equilibrium MD (DCP-NEMD) technique was employed to simulate gas permeation phenomena under a constant upstream pressure, in which the permeating molecules were modeled as Lennard-Jones particles. The dependencies of the permeance of helium and CO2 molecules on temperature and pore size were examined. For cylindrical pores about 8 and 6 angstrom in diameter, the calculated temperature dependencies for the permeance of helium molecules were similar to the tendencies predicted by the normal Knudsen permeation mechanism, while in the case Of CO2 permeation, a temperature dependency larger than helium and a significant deviation from the Knudsen mechanism were observed. The deviation was more obvious for the smaller 6 angstrom pore model. A simple gas permeation model that takes the effect of the pore wall potential field into consideration satisfactorily explained the permeation properties Of CO2 in the high temperature region. The permeation mechanism was also examined from the viewpoint of the lateral potential and density distribution in a micropore. The values for the potential within micropores, predicted from the observed temperature dependencies of the gas permeation rate and using the simple gas permeation model, were in good agreement with the depth of the potential field resulting from the given potential parameters. The findings also indicate that the density (pressure) difference in a micropore between the pore entrance and exit, which could be enhanced by an attractive pore wall potential, might be the true driving force for permeation, particularly in the high temperature region. (c) 2007 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Apr. 2007, JOURNAL OF MEMBRANE SCIENCE, 293(1-2) (1-2), 81 - 93, English
    [Refereed]
    Scientific journal

  • Tomohisa Yoshioka, Takashi Maki, Masashi Asaeda, Toshinori Tsuru
    Gas permeation properties through silica based metal-doped microporous membranes prepared by the sol-gel method were investigated. In order to control pore size and affinity with permeating gas molecules, especially with CO2 for CO2/N2 gas separation membranes, nitrates of Ni, Al, Mg metals, and ammonium salt of vanadium were added to silica colloidal solutions. The molar ratio of additives, Si/M was 9/1. CO2 and N2 adsorption measurements on pure silica and metal-doped silica powder samples were conducted to estimate the affinity of the membrane materials with those gases. Pure silica and Ni-doped silica showed the largest amount of adsorbed CO2. Ni-doped silica membranes showed no attract difference from a typical pure silica membrane for temperature dependencies of gas permeance, while Mg-doped silica membranes might have relatively smaller effective pores for CO2/N2 separation and the value of permeance ratio of 57 could be obtained at 50 ℃. On the other hand, V-doped silica membranes had larger pores and N2 gas permeance increased with decreasing temperature, which would result in lower performance of CO2 separation. Concerning the Al-doped silica membranes, the affinity with CO2 decreased by addition of Al. In addition, activation energy of He and H2 for permeation on Al-doped membranes became greater, which suggested densification of silica network because of Al dispersion in the dense phase.
    THE MEMBRANE SOCIETY OF JAPAN, Jan. 2007, MEMBRANE, 32(1) (1), 45 - 53, Japanese
    [Refereed]
    Scientific journal

  • Jianhua Yang, Tomohisa Yoshioka, Toshinori Tsuru, Masashi Asaeda
    Five kinds of micro-porous SiO2-ZrO2 (ZrO2; 50 mol%) membranes of slightly different pore sizes less than 1 nm were prepared by the sol-gel techniques to study the pervaporation characteristics of some aqueous solutions of organic chemicals. Since no direct evaluation techniques to determine the membrane pore-sizes less than I nm have yet been established, the pore sizes of the membranes fabricated were estimated by observing the permeances of gases of various molecular diameters at 200 degrees C.Some pervaporation measurements of aqueous solutions of organic chemicals such as iso-propanol, ethanol and acetone have been done with the membranes fabricated in order to study the effects of the membrane pore size and the molecular interaction with the pore wall on the pervaporation performance. The pervaporation results for IPA/water mixture at 10 wt.% of water and at 75 degrees C showed a long time dependency of IPA and water fluxes. The IPA flux decreased drastically, while that of water decreased slightly, giving a large separation factor, larger than 15,000, after several hours of pervaporation with water fluxes of 120-300 mol/m(2)h, for example.The observed concentration dependency of the IPA flux showed a maximum at around 48 mol% of IPA and then decreased with increasing IPA concentration in the feed. A similar behavior of the ethanol flux was observed for ethanol/water mixtures, but not for acetone/water mixtures. The acetone flux increased monotonously with the increase of acetone concentration in the feed.The pervaporation results obtained for the membranes of different pore sizes suggest that the separation performance depends largely on the pore size and also on the interaction between the molecules and the pore wall. (c) 2006 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Nov. 2006, JOURNAL OF MEMBRANE SCIENCE, 284(1-2) (1-2), 205 - 213, English
    [Refereed]
    Scientific journal

  • Toshinori Tsuru, Takehiro Kan-no, Tomohisa Yoshioka, Masashi Asaeda
    Porous titanium oxide membranes with pore sizes in the range of 2.5-22 nm were prepared by a sol-gel procedure, and were applied for decomposition of methanol and ethanol as model volatile organic compounds (VOCs) in a photocatalytic membrane reactor, where oxidation reaction occurs both on the surface and inside the porous TiO2 membrane while reactants are permeating via one-pass flow. Methanol was completely photo-oxidized by black-light irradiation to CO2 when methanol at a concentration of 100ppm was used at a feed flow rate of 500 x 10(-6) m(3)/min, but the conversion decreased when the MeOH concentration in the feed was increased. Pt-modification was carried out by photo-deposition, and led to a decrease in pore diameter. Using Pt-modified membranes, a nearly complete oxidation of methanol up to 10,000 ppm at a feed flow rate of 500 x 10-6 m(3)/min was observed. Thus, such membranes would be effective for purifying a permeate stream after one-pass permeation through the TiO2 membranes. The decomposition of ethanol is also discussed. (c) 2006 Elsevier B.V. All rights reserved.
    ELSEVIER, Sep. 2006, JOURNAL OF MEMBRANE SCIENCE, 280(1-2) (1-2), 156 - 162, English
    [Refereed]
    Scientific journal

  • T Tsuru, H Shintani, T Yoshioka, M Asaeda
    The steam reforming of methane for hydrogen production was experimentally investigated using catalytic membrane reactors, Consisting of a microporous silica top layer, for the selective permeation of hydrogen, and an alpha-alumina support layer, for catalytic reaction of the steam reforming of methane. An alpha-alumina support layer with a bimodal structure, which was proposed for the enhanced dispersion of Ni catalysts, was prepared by impregnating gamma-Al2O3 inside alpha-Al2O3 microfiltration membranes (1 mu m in pore diameter), and then immersing the membranes in a nickel nitrate solution, resulting in a bimodal catalytic support. The bimodal catalytic support showed a large conversion of methane at a high space velocity compared with a conventional catalytic membrane with a monomodal structure. The enhanced activity of Ni-catalysts in bimodal catalytic supports was confirmed by hydrogen adsorption measurements. A bimodal catalytic membrane, i.e. a silica membrane coated on a bimodal catalytic support, showing an approximate selectivity of hydrogen over nitrogen of 100 with a hydrogen permeance of (0.5-1) x 10(-5) m(3) m(-2) s(-1) kPa(-1) was examined for the steam reforming of methane. The reaction was carried out at 500 degrees C, and the feed and permeate pressures were maintained at 100 and 20 kPa, respectively. Methane conversion could be increased up to approximately 0.7 beyond the equilibrium conversion of 0.44 by extracting hydrogen from the reaction stream to the permeate stream. (c) 2006 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Mar. 2006, APPLIED CATALYSIS A-GENERAL, 302(1) (1), 78 - 85, English
    [Refereed]
    Scientific journal

  • T Tsuru, M Miyawaki, T Yoshioka, M Asaeda
    Porous silica-zirconia membranes with pore diameters from 0.8 to 2 nm were prepared by a sol-gel process, and applied to the separation of alcohols (hexanol, octanol, decanol) and alkanes (hexane, decane, tetradecane) in ethanol solutions by reverse osmosis over the temperature range from 25 to 60 degrees C A silica-zirconia membrane with a pore diameter of I nm showed a molecular weight-cut-off (MWCO) of 200 in ethanol solutions. Rejection increased with the applied pressure, for both alcohol and alkane solutes. However, the rejection of alcohols was found to decrease with temperature, while that for alkanes remained nearly constant. The separation characteristics were examined for the following membrane parameters: solvent permeability, L-P, reflection coefficient, sigma, and solute permeability, P, based on the Spiegler-Kedent equation. The viscosity of solutions and the diffusivity of alkanes and alcohol solutes in nano-sized pores were found to show a larger temperature dependency than in bulk. The diffusivity of alkane solutes showed the same temperature dependency as the viscosity of ethanol in nano-sized pores, while the diffusivity of alcohol solutes showed a larger temperature dependency than the viscosity of ethanol, probably because of a larger interaction between alcohol solutes and the hydrophilic surface of silica-zirconia membranes. Diffusion experiments were carried out to confirm the temperature dependency of the diffusivities in nano-sized pores. A bilayer model verified that solute permeabilities by reverse osmosis and diffusion experiments were consistent with each other. 0 2005 American Institute of Chemical Engineers AIChE J, 52: 522-531,2006
    JOHN WILEY & SONS INC, Feb. 2006, AICHE JOURNAL, 52(2) (2), 522 - 531, English
    [Refereed]
    Scientific journal

  • Transport properties of condensable and non-condensable gas mixtures through microporous silica membranes studied with molecular dynamics simulation
    T Yoshioka, T Tsuru, M Asaeda
    Non-equilibrium molecular dynamics simulations of condensable vapor permeation and permeation of condensable and non-condensable gas mixtures through a sub-nano-scale pore were conducted on a virtual amorphous silica membrane that was prepared by the melt-quench procedures. In the permeation properties of ethane-like U particle through a pore of 8 A in diameter, a surface diffusion-like temperature dependency was observed in a relatively high temperature region (400-800 K), while at around room temperatures, the permeance decreased with decreasing temperature. The permeance of non-condensable nitrogen-like particles. which have smaller affinity with the pore surface than ethane, was smaller than those of ethane, and a surface diffusion-like temperature dependency curve was observed for the temperature range from room temperature up to 800 K. In simulations of permeation for ethane/nitrogen binary mixtures at 260 K, a temperature below the critical temperature (T-C) of actual ethane, the concentration dependency of ethane permeance was relatively small in the low concentration (partial pressure) region, and above a higher specific concentration, the permeance largely decreased. The nitrogen permeance decreased with increasing ethane concentration in the low ethane concentration region, and was smaller at any partial pressure conditions compared with those observed in single nitrogen gas permeation simulations. These findings indicate that a condensable component that has larger interaction with the pore surface obstructs the transport of a non-con den sable one to decrease its permeance. The formation of a micropore filling phase of condensable gases in a micropore at temperatures below T-C and at sufficiently high pressures could also decrease the permeance of the condensable component. This molecular dynamics simulation revealed that the micropore filling phenomenon should play an important role in determining the permeation performance of condensable gases through a micropore.
    SOC CHEMICAL ENG JAPAN, Jan. 2006, KAGAKU KOGAKU RONBUNSHU, 32(1) (1), 11 - 17, Japanese
    [Refereed]
    Scientific journal

  • T Tsuru, Y Ohtani, T Yoshioka, M Asaeda
    Nanoporous TiO2 membranes (1 cm in diameter, 9 cm in length) were prepared by coating colloidal TiO2 sol solutions on the outer surface of cylindrical porous membranes (average pore diameter I um) and firing at 450&DEG; C, and applied in a photocatalytic membrane reactor. In this system, a feed stream is forced through the membrane to yield a purified permeate where organic pollutants are degraded by photocatalytic reaction. Methylene blue (MB) was used as a model solute and was irradiated with blacklight lamps (BL) to promote the photocatalytic reaction. TiO2 membranes with an average pore diameter of 10nm, yielded a normalized permeate concentration relative to feed concentration, C-p/C-f, of approximately 40% (60% rejection), based on the molecular sieving effect without BL irradiation. The normalized permeate concentration of MB decreased to 5% under BL irradiation, depending on experimental conditions such as feed concentration and applied pressure. The molecular sieving and the photocatalytic reaction can be combined to improve the selectivity. Permeate volume flux without BL irradiation decreased with an increase in feed concentration of MB, because of pore blocking by MB. On the other hand, the permeate flux increased with BL irradiation and showed approximately constant values irrespective of MB concentration. This suggested that the permeate flux was restored by photocatalytic degradation of MB which fouled the membranes.
    SOC CHEMICAL ENG JAPAN, Mar. 2005, KAGAKU KOGAKU RONBUNSHU, 31(2) (2), 108 - 114, Japanese
    [Refereed]
    Scientific journal

  • T Tsuru, K Yamaguchi, T Yoshioka, M Asaeda
    Methane steam reforming, with and without added oxygen, was theoretically and experimentally investigated using microporous silica membranes, thus allowing the permeation of hydrogen as well as other gases in reactants and products. A simulation of catalytic membrane reactors was carried out for a cocurrent, isothermal, and plug-flow-type membrane reactor with the selective permeation of hydrogen through microporous membranes. The effect of operating conditions on the conversion of methane and hydrogen production is discussed with the aid of two dimensionless numbers, the Damkohler number (Da) and the permeation number (theta). Methane conversion, X-CH4, has approximately the same dependency on permeation number in terms of the permeability ratios of hydrogen over nitrogen, whereas the purity of hydrogen in the permeate increased with increasing hydrogen selectivity. Catalytic membrane reactors, consisting of a silica microporous layer and a Ni-catalyst layer, were prepared. The permeability ratio of hydrogen over steam, alpha(H-2/H2O), which ranged from 1 to 20, showed a relatively good correlation with that for helium over hydrogen, alpha(He/H-2). Catalytic membrane reactors showing a hydrogen selectivity over nitrogen of 30-100, with hydrogen permeances of 0.5(-3) X 10(-7) mol m(-2) s(-1) Pa-1 were applied to the steam reforming of methane with and without the addition of oxygen. The reaction was carried out at 500degreesC, and the feed and permeate pressure were maintained at 100 and 20 kPa, respectively. Methane conversion, X-CH4, increased up to approximately 0.8 beyond the equilibrium conversion of 0.44 by extracting hydrogen in permeate stream. (C) 2004 American Institute of Chemical Engineers
    JOHN WILEY & SONS INC, Nov. 2004, AICHE JOURNAL, 50(11) (11), 2794 - 2805, English
    [Refereed]
    Scientific journal

  • T Tsuru, K Yamaguchi, T Yoshioka, M Asaeda
    The steam reforming of methane with addition of a small amount of oxygen was simulated in a co-current, isothermal and plug-flow-type membrane reactor with selective permeation of hydrogen. The effect of operating conditions on the conversion of methane and the permeated hydrogen yield was investigated using two dimensionless numbers, the Damkohler number and the permeation number, theta. Methane conversion, X-CH4, shows approximately the same dependency on permeation number in terms of the permeability ratio of hydrogen to nitrogen, while hydrogen purity in the permeate increased with an increase in hydrogen selectivity. As for heat balance of the membrane reactor, the addition of oxygen, which generates heat of combustion, in feed at O/C of 0.3 to the endothermic steam-reforming reaction, is required to maintain the membrane reactor autothermal. For the case of heat-balance of membrane reactor system, which considers the heat balance of the membrane reactor and the heat of combustion of the retentate stream, the system can be autothermal for the case of methane conversion of 0.7-0.8.
    SOC CHEMICAL ENG JAPAN, May 2004, KAGAKU KOGAKU RONBUNSHU, 30(3) (3), 346 - 352, Japanese
    [Refereed]
    Scientific journal

  • T Tsuru, H Kondo, T Yoshioka, M Asaeda
    JOHN WILEY & SONS INC, May 2004, AICHE JOURNAL, 50(5) (5), 1080 - 1087, English
    [Refereed]
    Scientific journal

  • Transport Properties of Condensable Gases through Microporous Silica Membranes
    YOSHIOKA T.
    2004, Transactions of the Materials Research Society of Japan, 29(7) (7), 3247 - 3250
    [Refereed]

  • T Yoshioka, T Tsuru, M Asaeda
    A boundary driven non-equilibrium molecular dynamics simulation method was used to study gas permeation mechanisms through microporous amorphous silica membranes. Two types of silica membranes were prepared, one by random atom-removing and the other by regular pore-digging procedures. The former was a dense membrane that served as a model for network pores formed by silica polymers and the latter had a penetrating cylindrical pore which simulated an inter-particle pore. The permeances of He, H-2 and Ne through network models with densities of 1.7 and 1.8 g cm(-3) increased with decreasing temperature, while activated permeation was observed for the denser models. Deviations in the permeation properties from those predicted by the Knudsen model became greater with increasing membrane density as the result of molecular sieving effects. The permeance of H-2 through a cylindrical pore 0.6 nm in diameter was greater than that for He at all temperatures examined as predicted by the Knudsen model, and the greater interaction of CO2 with the pore surface yielded a larger temperature-dependency curve for permeance, compared to He and H-2 . The simulated permeation properties of several gases were in agreement with experimental data on actual microporous silica membranes, indicating the qualitative validity of the microporous structure model composed of small openings in a silica network phase and larger inter-particle pores.
    TAYLOR & FRANCIS LTD, Jan. 2004, MOLECULAR PHYSICS, 102(2) (2), 191 - 202, English
    [Refereed]
    Scientific journal

  • Effect of Molecular Interactions on Gas Permeation Properties through a Microporous Silica Membrane Studied with Molecular Dynamics Simulation
    2004, Transactions of the Materials Research Society of Japan, 29(7) (7), 3283 - 3286

  • T Tsuru, T Toyosada, T Yoshioka, M Asaeda
    A photocatalytic membrane reactor, in which permeation of solutes through a membrane and a photocatalytic reaction occur simultaneously, that is, a photocatalytic membrane reactor, is described. Using trichloroethylene (TCE), a decomposition ratio in excess of 95% in the permeate stream to that in the feed stream was achieved by means of porous titanium oxide (TiO2) membranes, when approximately I ppm TCE solution was fed to the TiO2 membranes under irradiation by a blacklight. The decomposition ratio, defined as the concentration ratio of the permeate to the feed stream, decreased with applied pressure and the feed concentration. A proposed photocatalytic reaction model where a photocatalytic reaction in the outer reaction zone and in the inner reaction zone under membrane permeation conditions is consistent with the observed experimental data.
    SOC CHEMICAL ENG JAPAN, Sep. 2003, JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 36(9) (9), 1063 - 1069, English
    [Refereed]
    Scientific journal

  • T Tsuru, M Miyawaki, H Kondo, T Yoshioka, M Asaeda
    Silica-zirconia (SZ, molar ratio 9/1) membranes, the pore size of which were adjusted in a range of approximately 13 1-3 nm, were prepared by the sol-gel process. Several of these membranes were modified via a gas-phase reaction with trimethylchlorosilane (TMS) at 200 degreesC. Various types of pure solvents were permeated at temperatures in the range of 20-60 degreesC. The collected data shows that the transport mechanism through the unmodified membranes does not obey the viscous flow mechanism, since pure solvent permeabilities multiplied by the viscosity, L(p)mu, which should be constant for the case of the viscous-flow mechanism, increased with temperature. On the other hand, SZ membranes modified with TMS showed a relatively constant L(p)mu, suggesting that the viscous flow mechanism holds. The nanofiltration of ethanol solutions with alkanes (hexane, decane, tetradecane) and alcohols (hexanol, octanol, decanol) as solutes was investigated. An SZ membrane having an average pore size of 1 nm showed a molecular weigh cut-off of approximately 200 and an approximate permeate flux of 3 kg m(-2) h(-1) at 60 degreesC under an applied pressure of 30 bar. Rejections of alkanes were almost constant irrespective of temperatures, while those of alcohols decreased with temperature. (C) 2003 Elsevier Science B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Jul. 2003, SEPARATION AND PURIFICATION TECHNOLOGY, 32(1-3) (1-3), 105 - 109, English
    [Refereed]
    Scientific journal

  • T Tsuru, Y Takata, H Kondo, F Hirano, T Yoshioka, M Asaeda
    Silica-zirconia membranes having pore sizes in the range 0.5-2 nm, determined using water as a condensable gas (vapor) by nanopermporometry, were prepared by the sol-gel process, and used in gas permeation experiments. The permeability ratio of He/N-2 approached the Knudsen value (= 2.6) for pore sizes larger than 2 nm. It then decreased with decreasing pore size, probably because of an enhanced contribution of surface diffusion in the small pore, and showed a minimum at an approximate pore size of 1 rim. It then increased to approximately 50 for a membrane having pore sizes of 0.3 nm. For the case of He/SF6, the curve appears to shift to a larger Kelvin diameter, probably because of the larger molecular size of SF6 as well as adsorption. The effects of non-condensable gases (He and N-2) were examined using silica-zirconia membranes of 2 and 0.8 nm in pore size. The pore size distribution (PSD) curves measured by He and N-2 were in good agreement with each other for membranes having a pore size as large as 2 nm. On the other hand, for the case of porous membranes having small pore sizes, PSD curves measured using He were shifted to a smaller pore size, compared with those measured by N-2. This suggests the existence of micropores, which allowed the permeation of only He. Moreover, nanopermporometry was applied to MFI zeolite membranes to characterize selective (intracrystalline) and non-selective pores (intercrystalline) using hexane, and the data were in reasonable agreement with the observed separation performances. (C) 2003 Elsevier Science B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Jul. 2003, SEPARATION AND PURIFICATION TECHNOLOGY, 32(1-3) (1-3), 23 - 27, English
    [Refereed]
    Scientific journal

  • T Tsuru, T Kan-no, T Yoshioka, M Asaeda
    Photocatalytic membrane reactors using porous titanium oxide membranes having pore sizes of several nanometers were utilized for a gas-phase reaction of methanol. Air mixed with methanol (MeOH) vapor, the concentration of which was controlled in the range of 500-6000 ppm, was fed to the photocatalytic membrane reactor in the range of 50-500 cm(3)/min using several types of flow patterns. Photocatalysis with membrane permeation resulted in a large decomposition rate, compared to photocatalysis without membrane permeation. The characteristics of the reaction such as decomposition ratio of MeOH, the conversion of the decomposed MeOH to CO2 and H2O were found to be a function of the residence time in the reactor. The photocatalytic reaction was analyzed based on pseudo-first-order kinetics to ascertain its simplicity, and the fitted curves were found to be in a relatively good agreement with the experimental data. Apparent rate constants with and without membrane permeation were 2.5 and 1.5 X 10(-6) m s(-1), respectively, indicating that the performance of the photocatalytic reaction system with membrane permeation was enhanced. (C) 2003 Elsevier B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Jul. 2003, CATALYSIS TODAY, 82(1-4) (1-4), 41 - 48, English
    [Refereed]
    Scientific journal

  • T Yoshioka, T Tsuru, M Asaeda
    Molecular dynamics (MD) simulations of condensable vapor permeation through sub-nano scale pores were conducted for a virtual amorphous silica membrane, prepared by melt-quench procedures. The simulated permeance of C2H6 (T-C = 305 K)-like LJ particles through an 8 Angstrom in diameter pore showed a surface diffusion-like temperature dependency in the relatively high temperature region (400-800 K), while at around 300 K, the permeance decreased with decreasing temperature. That is, a maximum was observed in the temperature dependency curve for permeance. The critical temperature, T-C of the permeating condensable vapor could be a contributing factor in the permeation properties through the micropore. The simulated permeance of C2H6 at 260 K decreased with increasing mean pressure. At low pressure, where micropore filling would not be expected to occur, an almost gas like permeation was observed even at temperatures below the T-C, while under micrpore filling conditions at a relatively high pressure, the permeance abruptly decreased. Adsorption simulations were also conducted on the same unit cell, and the mobility of the adsorbed molecules in the micropore filling phase were smaller than those in the lower density phase. Through this investigation of temperature and pressure dependency of permeance, it can be concluded that the development of the micropore filling phase led to a decrease in permeance, and transport as the condensed filling phase through the micropore was an activated process. (C) 2003 Elsevier Science B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Jul. 2003, SEPARATION AND PURIFICATION TECHNOLOGY, 32(1-3) (1-3), 231 - 237, English
    [Refereed]
    Scientific journal

  • Gas permeation properties and methylation of toluene by MFI zeolite membranes with different Si/Al ratios
    Y Takata, T Tsuru, T Yoshioka, M Asaeda
    MFI zeolite membranes having different Si/Al ratios were prepared by secondary growth of crystalline colloidal seeds under hydrothermal conditions. An MFI membrane of Si/Al=infinity showed a n-C4H10 permeance of 1.5X10(-5) m(3) (STP)m(-2) s(-1) kPa(-1) and a n/i-C4H10 selectivity of 15 at 150degreesC. By addition of Al into MFI membranes, the zeolite layers appeared to be randomly oriented, and n/i-C4H10 selectivities were decreased. Methylation of toluene using MFI catalytic membrane reactors was carried out at 400-500degreesC. Toluene conversions increased with reaction temperature and a maximal p-xylene selectivity of 80% was achieved. suggesting the effectiveness of MFI catalytic membrane reactors.
    SOC CHEMICAL ENG JAPAN, May 2003, KAGAKU KOGAKU RONBUNSHU, 29(3) (3), 427 - 431, Japanese
    [Refereed]
    Scientific journal

  • Organic/inorganic nanohybrid membranes for nanofiltration of nonaqueous solutions
    T Tsuru, H Kondo, T Yoshioka, M Asaeda
    Silica/zirconia (SZ; Si/ Zr molar ratio = 9/1) membranes having pore sizes in the range of 1similar to3 nm were prepared by the sol-gel process. Organic/inorganic hybrid membranes were developed by modifying the surface of the silica-zirconia porous membranes via a gas-phase reaction with trimethylchlorosilane (TMCS) to give a surface that was modified with a monolayer of TMCS. Using nanopermporometry, it was found that the inner surface of membrane pores with diameters larger than several nms were successfully modified with TMCS. TMCS-modified membranes showed approximately the same permeability, L, irrespective of water concentration (10 and 100 ppm) in hexane. In contrast, an unmodified membrane, showed a decrease in L, with increasing water concentration, which was pronounced at low permeation temperatures. This suggests that small amounts of water adsorbed to the inner surface of unmodified silica-zirconia membranes and blocked the permeation of hexane.
    MATERIALS RESEARCH SOCIETY, 2003, MEMBRANES-PREPARATION, PROPERTIES AND APPLICATIONS, 752, 97 - 102, English
    [Refereed]
    International conference proceedings

  • Structurally composite membranes of titanium oxide and titanium phosphorus oxide for proton conduction at intermediate temperatures
    T Tsuru, Y Yagi, Y Kinoshita, T Yoshioka, M Asada
    Composite membranes of titanium oxide and phosphorus oxide (TiP) were prepared by the sol-gel method and evaluated for use as proton conductive materials at intermediate temperatures. Titanium phosphorus oxide sol solutions were prepared by the hydrolysis of titanium isopropoxide (TTIP) using hydrochloric acid as a catalyst in isopropanol solutions, and the addition of an appropriate amount of phosphoric acid (H3PO4). A new concept for structurally composite membranes is proposed for proton conductive membranes. A composite membrane, Ti/TiP, where the pores of a porous titanium oxide layer are filled with titanium phosphorus oxide, was found to be effective for high electrical conductivity as well as mechanical strength. Electrical conductivities as high as 0.1 and 0.06 S cm(-1) at 100 and 300 degreesC, respectively, under a partial pressure of water of 50 kPa, was achieved for the TV TiP membranes.
    MATERIALS RESEARCH SOCIETY, 2003, MEMBRANES-PREPARATION, PROPERTIES AND APPLICATIONS, 752, 103 - 108, English
    [Refereed]
    International conference proceedings

  • T Tsuru, D Hironaka, T Yoshioka, M Asaeda
    Titania (TiO2) membranes with molecular weight cut-offs controlled at 250, 400, and 2000 were successfully prepared by the sol-gel process. These porous membranes rejected electrolytes based on Donnan exclusion, and the permeate volume flux, based on the electroviscous effect, was pH-dependent, similar to polymeric porous membranes. Moreover, divalent counterions (Ca2+,Mg2+) which were strongly adsorbed by ion-exchange at alkali pH, drastically reduced volume flux, compared with monovalent cations (Ne (+), K+); this tendency was pronounced for porous membranes with smaller pore sizes. The evidence for hydrodynamic resistance by the adsorbed divalent cations was shown based on permeation and zeta potential measurements of mixtures.
    ELSEVIER SCIENCE BV, Sep. 2002, DESALINATION, 147(1-3) (1-3), 213 - 216, English
    [Refereed]
    Scientific journal

  • Y Takata, T Tsuru, T Yoshioka, M Asaeda
    MFI zeolite membranes were prepared by secondary growth on alpha-alumina microfiltration membranes. Colloidal silicalite, the size of which was approximate to100 nm, was used as seed crystals. An MFI membrane, in which the zeolite layer was oriented to the (10 1) plane, showed a n-C4H10, permeance of 1.5 x 10(-5) m(3)(STP)m(-2)s(-1)kPa(-1) and a n-li-C4H10 selectivity of 15 at 150 degreesC. N-2 permeated faster than He at temperatures lower than 150 degreesC, probably because of surface diffusion of the adsorbed N-2 in the Henry regime. After ion-exchanging the MFI zeolite membranes from the Na-type to the H-type, the alkylation of toluene with methanol was carried out. A maximal p-xylene selectivity of 80% was achieved using the H-MFI zeolite membranes at 450-500 degreesC. (C) 2002 Elsevier Science Inc. All rights reserved.
    ELSEVIER SCIENCE BV, Jul. 2002, MICROPOROUS AND MESOPOROUS MATERIALS, 54(3) (3), 257 - 268, English
    [Refereed]
    Scientific journal

  • T Tsuru, D Hironaka, T Yoshioka, M Asaeda
    Titania membranes were prepared by sol-gel processes. Molecular weight cut-offs (MWCO) were successfully controlled in the range from 500 to 1000 with pure water permeabilities of 0.6-1.5 x 10(-11) m(3) m(-2) s(-1) Pa-1. Nanofiltration experiments were carried out for various types of electrolytes (NaCl, Na2SO4, MgCl2 MgSO4) using several membranes having different MWCOs (400, 500, > 1000). Rejection showed the minimum values near the isoelectric point (IEP) which were determined by streaming potential measurements. Larger rejections were obtained for the case where electrolytes having divalent co-ions were nanofiltrated, while low rejection were observed for the case of electrolytes having divalent counterions. On the other hand, permeate volume fluxes were maximized near IEP and the fluxes were almost the same irrespective of types of electrolytes. However, permeate volume fluxes decreased at pH higher than IEP. The dependency was pronounced for the case of divalent counterions and smaller pore diameters, probably because of larger hydrodynamic resistance by ionically-adsorbed counter ions. (C) 2001 Elsevier Science BN. All rights reserved.
    ELSEVIER SCIENCE BV, Oct. 2001, SEPARATION AND PURIFICATION TECHNOLOGY, 25(1-3) (1-3), 307 - 314, English
    [Refereed]
    Scientific journal

  • T Yoshioka, T Tsuru, M Asaeda
    Gas permeation mechanisms through a micropore of a vitreous silica (v-SiO2) membrane were studied using a molecular dynamics (MD) simulation. Virtual v-SiO2 membranes were prepared by the melt-quench methods using the modified Born-Mayer-Huggins pair potential and Stillinger-Waber three-body interactions. The particle-generating non-equilibrium MD technique was employed in order to simulate gas permeation phenomena, where permeating molecules were modeled as Lennard-Jones particles. This simulation method accommodates a change in the number of particles in a unit cell and, hence, an accurate simulation of the steady-state process of permeation can be achieved, The dependencies of permeance on temperature and pressure were discussed. For cylindrical pores of about 5 Angstrom in diameter, the calculated temperature dependencies of the permeance of He-like LJ particles were similar to those predicted by the normal Knudsen permeation mechanism, while, for CO2 permeation, a temperature dependency larger than He and a significant deviation from the Knudsen's could be observed. In the relatively high-temperature region (400-800 K), the simulated permeance of CO2 was nearly independent of the upstream pressure, while at the temperature below 300 K, a pressure dependency of permeance was observed. Simulations of adsorption conducted on the same unit cell yielded a Henry-type isotherm at 400 K and a Langmuir-type isotherm at 260 K. These results indicate that gas-Eke permeation occurred in the higher-temperature region, where the permeation flux is proportional to the pressure drop across the pore. However, at lower temperatures, the transports of molecules as some type of adsorption phase might be dominant in such a small pore. A simple gas permeation model, considering the effect of the pore wall potential field and Langmuir type adsorption within a micropore explained those permeation properties of CO2 well. (C) 2001 Elsevier Science B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Oct. 2001, SEPARATION AND PURIFICATION TECHNOLOGY, 25(1-3) (1-3), 441 - 449, English
    [Refereed]
    Scientific journal

  • T Yoshioka, E Nakanishi, T Tsuru, M Asaeda
    Permeation mechanism of inorganic gases was studied experimentally, and theoretically through microporous silica membranes prepared by the sol-gel method. Inorganic gas permeation was measured using the membranes with subnano pores in diameter. The permeance of He increased with increasing temperature for various cases, while that of CO2, O-2 and N-2 decreased. In particular; the observed temperature dependency, of CO2 was greater than those of other gases. In such small pores, the interaction energy between a permeant molecule and the pore wall call affect gas-permeation properties. A simple gas-permeation model is used considering the effect of the attractive or repulsive pore-wall potential field, which deviates from thc ambient gas phase of the gas molecule concentration (pressure) in a pore. Thc model call explain the experimental gas-permeation properties successfully Potential curves of CO2 and N-2 in a silica pore were also calculated to predict the permeation ratio of CO2/N-2. This model call help understand further the gas-permeation mechanism in micropores.
    AMER INST CHEMICAL ENGINEERS, Sep. 2001, AICHE JOURNAL, 47(9) (9), 2052 - 2063, English
    [Refereed]
    Scientific journal

  • T Tsuru, T Toyosada, T Yoshioka, M Asaeda
    A new type of photocatalytic reaction system, in which filtration and a photocatalytic reaction occur simultaneously, is reported. The concentration of trichloroethylene (TCE) in permeate stream decreased by approximately 5 ppm while TCE permeating porous TiO2 membranes under conditions of blacklight irradiation. In addition, membrane fouling by polyethyleneimine, which caused a decrease in permeate flux, was also found to be reduced by photocatalytic reaction.
    SOC CHEMICAL ENG JAPAN, Jun. 2001, JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 34(6) (6), 844 - 847, English
    [Refereed]
    Scientific journal

  • T Tsuru, T Hino, T Yoshioka, M Asaeda
    An evaluation of nano-order pore size of membranes was carried out using permporometry, the basic principle of which is based on capillary condensation of vapor and the blocking effect of permeation of a non-condensable gas. A computer-controlled apparatus was constructed, where liquid was injected by a syringe pump and nitrogen was used as a carrier, and was applied to the evaluation of the pore size of ceramic membranes prepared from a silica-zirconia composite. The pore size distribution, based on the Kelvin equation (Kelvin diameter), was evaluated over a range of 0.5-30 nm, using water as a condensable vapor. Vapors used in the present study were water, methanol, ethanol, isopropanol, carbon tetrachloride, and hexane. For the case of relatively large pore sizes (larger than 1 nm, based on water vapor), pore size distribution obtained by water vapor agreed very well with those by carbon tetrachloride and hexane. However, pore sizes measured using alcohols were found to be smaller than those determined by water vapor. For the case of pore sizes smaller than 1 nm, the adsorption layer before capillary condensation appears to play an important role. (C) 2001 Elsevier Science B.V. All rights reserved.
    ELSEVIER SCIENCE BV, May 2001, JOURNAL OF MEMBRANE SCIENCE, 186(2) (2), 257 - 265, English
    [Refereed]
    Scientific journal

  • T Tsuru, T Sudoh, T Yoshioka, M Asaeda
    Porous membranes having various average pore sizes, ranging from 1 to 4 nm, were prepared from silica-zirconia composite colloidal sols by sol-gel processes, and were used for nanofiltration (NF) experiments in non-aqueous solutions of ethanol and methanol. Silica-zirconia membranes, which were tested in pure alcohol solutions for the first time after the preparation of the membrane, showed a gradual decrease in flux for approximately 100 h and then reached a steady flux. When the feed, after reaching the steady flux with ethanol, was changed to another alcohol, steady flux was attained after only several hours. Ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (PEG) of various molecular weights (PEG400, 600, 1000, and 2000) were nanofiltrated in methanol and ethanol solutions at 50 degreesC. Rejections in non-aqueous solutions increased with applied pressure, which is similar to aqueous solutions, Control of pore size of silica-zirconia membranes showing molecular weight cut-offs in methanol solutions at 300, 600, 1000, and >1000, respectively, was possible by the appropriate choice of colloidal particle sizes. Rejection in methanal solution showed a tendency similar to that in ethanol solution, while rejection in methanol was slightly larger than in ethanol solutions. In addition, rejection in water was much smaller than in methanol solution. For example, the rejection of PEG600 in water and methanol was 0.03 and 0.74, respectively. These results suggest that solvent type plays an important role in determining rejection, ass result of the interaction with solvents and/or membrane surface. (C) 2001 Elsevier Science B.V. All rights reserved.
    ELSEVIER SCIENCE BV, Apr. 2001, JOURNAL OF MEMBRANE SCIENCE, 185(2) (2), 253 - 261, English
    [Refereed]
    Scientific journal

  • T Tsuru, T Tsuge, S Kubota, K Yoshida, T Yoshioka, M Asaeda
    Catalytic membranes, which have hydrogen permselectivity over other gaseous molecules and catalytic activity for methane steam reforming, were prepared by 2 different procedures and applied to methane steam reforming at 450-500degreesC. Type A catalytic membranes were manufactured by the preparation of a hydrogen separation layer from silica-zirconia colloidal sols, followed by the application of a nickel catalyst coating. Type B catalytic membranes were prepared via the impregnation of a nickel catalyst inside the a-alumina porous substrates, followed by the application of a coating on the hydrogen separation layer. Hydrogen permselectivity over nitrogen was degraded by coating the catalyst layer, as in the Type A membranes, and in addition, methane conversion decreased with time probably because of catalyst sintering or carbon deposition. Type B catalytic membranes showed a steady conversion for a longer period than did Type A, and the permeability ratio of hydrogen to nitrogen was approximately 200; therefore, Type B was found to be the effective route to preparing catalytic membranes. Methane steam reforming through the use of catalytic membranes revealed that methane conversion beyond the equilibrium conversion levels could be achieved either by sweeping the permeate stream or by pressurizing the feed stream at 6 bar and not using sweeping gas.
    MARCEL DEKKER INC, 2001, SEPARATION SCIENCE AND TECHNOLOGY, 36(16) (16), 3721 - 3736, English
    [Refereed]
    Scientific journal

  • H Kanda, M Miyahara, T Yoshioka, M Okazaki
    An improved condensation model for the estimation of pore-size distribution in the range of nanometers is examined. In the authors' previous paper, the model proved its reliability in computer experiments employing the molecular dynamics technique. The model is tested here in a real experimental system with a MCM-41-like ordered mesoporous silicate, FSM-16. The study includes how to find the adsorbate-solid interaction strength, which is taken into account as an additional contribution for condensation other than the Kelvin effect. The true pore size of the material is separately determined to be 3.2 +/- 0.2 nm by high-resolution transmission electron microscopy observation, and by a "colloidal particle adsorption method". The conventional model for condensation, the Kelvin model, underestimates the pore size of FSM-16 to be 2.5 nn from the nitrogen isotherm. The present model successfully predicts the pore size to be 3.4 nm, and proves its reliability in the real experimental system. The effect of the pore wall's potential on the capillary coexistence relation is further discussed comparing ordered mesoporous silicates and the usual silica materials.
    AMER CHEMICAL SOC, Aug. 2000, LANGMUIR, 16(16) (16), 6622 - 6627, English
    [Refereed]
    Scientific journal

  • T Tsuru, T Sudou, S Kawahara, T Yoshioka, M Asaeda
    Inorganic nanofiltration membranes were prepared using silica-zirconia composite sols by the sol-gel method and applied for the permeation experiments of nonaqueous solutions. Pure solvent permeabilities of methanol, ethanol, and l-propanol were measured at temperatures from 25 to 60 degrees C. For membranes having pore sizes as large as 70 nm, the permeation mechanism of alcohols obeys the viscous flow mechanism irrespective of types of alcohols. On the other hand, the permeation mechanism through porous silica-zirconia membranes having pore diameters of 1 to 5 nm was found to be different from the viscous flow mechanism; small molecules showed larger permeabilities than large molecules. Activation energies of solvent permeability were found to be larger for large molecules and for membranes of smaller pore size. (C) 2000 Academic Press.
    ACADEMIC PRESS INC, Aug. 2000, JOURNAL OF COLLOID AND INTERFACE SCIENCE, 228(2) (2), 292 - 296, English
    [Refereed]
    Scientific journal

  • M Miyahara, H Kanda, T Yoshioka, M Okazaki
    We modeled condensation phenomena within cylindrical nanopores as a possible replacement for the Kelvin model that underestimates nanometer order pore sizes. The proposed model follows the simple concept of a continuum assumption similar to that for the Kelvin model. The difference was in the introduction of the contribution of the pore-wall potential and the curvature-dependent surface tension in our model. A molecular dynamics (MD) technique developed by the authors for isotherm determination was employed to test the concept and the model. Several isotherms for Nn-like Lennard-Jones (LJ) particles in a silicate-like cylindrical pore with various diameters from 2 to 4 nm were obtained through MD simulations, and a relation between pore diameter and critical condensation pressure was determined. The present model successfully described the relation to demonstrate its reliability. The validity of the proposed model was examined also from the aspect of the shape of the meniscus and the pressure profile in the condensed phase, and gave fairly good agreement.
    AMER CHEMICAL SOC, May 2000, LANGMUIR, 16(9) (9), 4293 - 4299, English
    [Refereed]
    Scientific journal

  • T Tsuru, S Izumi, T Yoshioka, M Asaeda
    The effect of temperature on nanofiltration performance was examined using three inorganic membranes with a molecular-weight cutoff of approximately 200, 600, and 2, 000, respectively. The inorganic porous membranes were prepared from silica-zirconia colloidal sols and used in nanofiltration experiments for neutral solutes over a temperature range of 20 to 60 degrees C. The rejection of solutes decreased with an increase in temperature for the membranes while the permeate volume flux increased. Three transport coefficients-refection coefficient, solute permeability, and water permeability-were obtained using the Spiegler-Kedem equation, which accounts for the contribution of convection and diffusion to solute flux. As a result, the reflection coefficient corresponding to the fraction of solutes reflected by the membrane in convective flow was almost constant, irrespective of experimental temperature. Solute permeabilities, however, increased with temperature. The dependency was larger for larger solutes and membranes with smaller pore diameters. Therefore, the hindered diffusion of solutes through micropores was indicative of an activated process. Moreover; pure water permeability, after correction for the temperature effect on viscosity, also increased with experimental temperature.
    AMER INST CHEMICAL ENGINEERS, Mar. 2000, AICHE JOURNAL, 46(3) (3), 565 - 574, English
    [Refereed]
    Scientific journal

  • M Miyahara, T Yoshioka, J Nakamura, M Okazaki
    We propose a simple method for identifying interaction strength between an adsorbate molecule and a solid surface. The interaction strength is necessary for precise evaluation of pore sizes of the nanometer order, in which the conventional Kelvin model fails to describe the condensation phenomena, and for which we proposed an alternative model taking account of the effect of attractive potential from pore walls on the condensation: The model contains a constant to express the interaction strength between an adsorbate and a solid surface, and it should be determined from a standard isotherm. For investigation and verification of the method, standard adsorption isotherms were prepared by the grand canonical Monte Carlo simulations for the system of a Lennard-Jones particle on a homogeneous solid surface. The Frenkel theory was basically applied for this purpose because of its explicit inclusion of the interaction parameter within the equation. The theory shows good agreement with simulation results in a limited range of relative pressures from 0.005 to 0.25, while certain deviations exist in other portions of the isotherm. The result is that only the portion of the standard isotherm with good agreement should be used to evaluate the interaction strength employing the Frenkel theory. Through examinations in systems with various interaction strengths, it is found that the interaction strength is able to be evaluated correctly if the equation is applied to the range of surface coverage from 0.8 to 1.8 in all cases. The interaction constant calculated by this method is proved to have sufficient accuracy for use in characterization of nano-scale pores.
    SOC CHEMICAL ENG JAPAN, Feb. 2000, JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 33(1) (1), 103 - 112, English
    [Refereed]
    Scientific journal

  • Molecular Dynamics Study on Condensation in Cylindrical Nano-pores -Modeling and Verification-
    Minoru Miyahara, Hideki Kanda, Tomohisa Yoshioka, Morio Okazaki
    May 1998, Proceedings of Fundamentals of Adsorption 6, 249 - 254
    [Refereed]
    International conference proceedings

  • Condensation Model for Cylindrical Nano-Pores Applied to Mesoporous Silicate FSM-16
    Hideki Kanda, Minoru Miyahara, Tomohisa Yoshioka, Morio Okazaki
    May 1998, Proceedings of Fundamentals of Adsorption 6, 321 - 326
    [Refereed]
    International conference proceedings

  • M Miyahara, T Yoshioka, M Okazaki
    We developed a new molecular dynamics (MD) scheme, introducing the concept of the potential buffering field through which an adsorbed phase could interact with an imaginary gas phase. This simulation cell allowed us to conduct a MD simulation that allowed a change in the number of molecules to attain equilibrium with given equilibrium pressure, like a grand canonical Monte Carlo simulation. By taking another choice for the setting of the cell, the number of molecules stayed constant but the equilibrium pressure was able to be obtained easily by a new technique of ''particle counting method.'' The thus obtained equilibrium vapor phase pressure agreed with that obtained by Widom's particle insertion method. Some adsorption simulations within slitlike pores of 2 and 3 nm were carried out Adsorption phenomena could be observed from monolayer adsorption on a pore wall under a low relative pressure Co the capillary condensation under a high relative pressure. Thus the adsorption equilibrium relation could be determined. The critical relative pressure for capillary condensation was smaller than that predicted by the modified Kelvin equation. This MD method shall provide much benefit in studying interfaces, which is important for analyzing condensation in pores. (C) 1997 American Institute of Physics.
    AMER INST PHYSICS, May 1997, JOURNAL OF CHEMICAL PHYSICS, 106(19) (19), 8124 - 8134, English
    [Invited]
    Scientific journal

  • T Yoshioka, M Miyahara, M Okazaki
    A new capillary condensation model for nano-scale pores is proposed. The effect of the pore wall potential on the condensation phenomenon was considered in the model. The critical relative pressure at which the condensation phase is formed can be related to the pore size by the model. The curvature dependency of the surface tension was also taken into account. This is a new model based on hydrostatic analysis, and its feature is non-uniformity of the condensation phase caused by the potential field exerted by the pore walls. We carried out adsorption simulations within slit-like pores in the range of 2 - 4 nm in width by using a Molecular Dynamics (MD) method. In the simulations, equilibrium vapor pressure for an adsorbed state was able to be calculated by counting the number of adsorbate particles which desorbed from the pore and reached a border plane with imaginary vapor phase. We used argon-like Ld particles as the adsorbate and the adsorbent consisted of LJ carbon-like walls. For various pore widths, we simulated the adsorption phenomena to obtain the adsorption equilibrium relation, from the state of the surface adsorption on a pore wall under a low relative pressure to the state of the condensation under a high relative pressure. Consequently, significant discrepancy in the critical relative pressure for capillary condensation from the value predicted by the Kelvin model was reaffirmed, while the proposed model predicted well the critical relative pressure for condensation in nano-scale pores. The validity of the proposed model was examined also from the aspects of the shape of gas-condensate interface and pressure distribution in the condensed phase, and gave fairly good agreement.
    SOC CHEMICAL ENG JAPAN, Apr. 1997, JOURNAL OF CHEMICAL ENGINEERING OF JAPAN, 30(2) (2), 274 - 284, English
    [Refereed]
    Scientific journal

■ MISC
  • ラマン分光法を利用した中空糸RO/NF膜ナノポーラス構造のin situ解析
    中尾崇人, 中尾崇人, 明石真由美, 石橋美晴, 中川敬三, 中川敬三, 新谷卓司, 新谷卓司, 松山秀人, 松山秀人, 吉岡朋久, 吉岡朋久
    2021, 膜シンポジウム(CD-ROM), (33) (33)

  • Functions of Polymeric Additives in Thermally Induced Phase Separation Process of Poly(Vinylidene Difluoride)
    薮野洋平, 薮野洋平, 小松賢作, 新谷卓司, 中川敬三, 吉岡朋久
    2020, 膜, 45(6) (6)

  • NF/RO/FO 膜と液体透過現象の分子動力学シミュレーション
    吉岡 朋久
    Jul. 2019, 分離技術, 49(4) (4), 208 - 215, Japanese
    [Invited]
    Introduction scientific journal

  • 野村 幹弘, 山口 猛央, 高羽 洋充, 赤松 憲樹, 酒井 求, 吉岡 朋久, 稲田 飛鳥, 佐々木 雄史, 谷口 育雄, 長澤 寛規, 中川 敬三, 安川 政宏
    THE MEMBRANE SOCIETY OF JAPAN, 2019, MEMBRANE, 44(6) (6), 276 - 288, Japanese
    Meeting report

  • 神戸大学における革新的分離膜の創製
    NAKAGAWA Keizo, INADA Asuka, KAMIO Eiji, YOSHIOKA Tomohisa, MATSUYAMA Hideto
    Oct. 2018, 繊維学会誌, 74(5) (5), 186 - 192, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • Molecular Dynamics Simulation of Water Permeation in RO/FO Membranes
    YOSHIOKA TOMOHISA, 川勝孝博
    Jul. 2018, 膜(MEMBRANE), 43(4) (4), 154 - 160, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • M. Nomura, H. Nagasawa, T. Miyata, K. Akamatsu, I. Taniguchi, T. Shintani, E. Kamio, S. Kanehashi, K. Nakagawa, T. Yoshioka, M. Yasukawa, H. Takaba, M. Sakai
    THE MEMBRANE SOCIETY OF JAPAN, 2018, MEMBRANE, 43(6) (6), 252 - 252, Japanese
    Meeting report

  • 膜工学研究の将来展望
    MATSUYAMA HIDETO, YOSHIOKA TOMOHISA, KAMIO EIJI, NAKAGAWA KEIZO
    The Chemical Society of Japan, Aug. 2017, Cheimstry & Chemical Industry, 70(8) (8), 678 - 680, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • 計算機支援による多孔性セラミック膜の細孔径評価法開発
    YOSHIOKA TOMOHISA
    触媒学会, Jun. 2017, 触媒, 59(3) (3), 161 - 166, Japanese
    [Invited]
    Introduction scientific journal

  • KAMIO EIJI, YOSHIOKA TOMOHISA
    日本膜学会, 2017, 膜(MEMBRANE), 42(1) (1), 2 - 10, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • YOSHIOKA TOMOHISA, 高橋 麻里子
    2016, 膜(MEMBRANE), 41(1) (1), 22 - 29, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • Molecular Simulation for Microporous Inorganic Membrames and Application to Estimation of Gas Permeation Characteristics
    YOSHIOKA Tomohisa
    Nov. 2014, MEMBRANE, 39(6) (6), 357 - 365, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • 2A02 Information related education of Chemical Engineering in Hiroshima University
    YOSHIOKA Tomohisa
    Japanese Society for Engineering Education, 08 Aug. 2014, 工学教育研究講演会講演論文集, 26(62) (62), 138 - 139, Japanese

  • Molecular simulation assisted characterization of structures and gas permeation properties of microporous inorganic membranes
    YOSHIOKA Tomohisa
    Jul. 2014, MEMBRANE, 39(4) (4), 236 - 245, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • Development of microporous gas separation membranes assisted by molecular simulations
    YOSHIOKA Tomohisa
    Dec. 2010, Adsorption News, 24(4) (4), 6 - 13, Japanese
    [Invited]
    Introduction scientific journal

  • 膜分離技術開発の現状と今後の課題
    吉岡 朋久
    Sep. 2010, 分離技術, 40(5) (5), 76 - 83, Japanese
    [Invited]
    Introduction scientific journal

  • 下村 佳大, 金指 正言, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2010, 化学工学会 研究発表講演要旨集, 2010(0) (0), 903 - 903, Japanese

  • 金指 正言, 佐野 充典, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2010, 化学工学会 研究発表講演要旨集, 2010(0) (0), 913 - 913, Japanese

  • 孔 春龍, 金指 正言, 吉岡 朋久, 都留 稔了
    The Society of Chemical Engineers, Japan, 2010, 化学工学会 研究発表講演要旨集, 2010(0) (0), 918 - 918

  • 吉岡 朋久, 中田 章博, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2010, 化学工学会 研究発表講演要旨集, 2010(0) (0), 919 - 919, Japanese

  • 藤原 隆博, 吉岡 朋久, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2010, 化学工学会 研究発表講演要旨集, 2010(0) (0), 930 - 930, Japanese

  • 重本 浩伸, 金指 正言, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2010, 化学工学会 研究発表講演要旨集, 2010(0) (0), 934 - 934, Japanese

  • 高圧条件における多孔性セラミック膜のCO2透過および分離特性
    吉岡 朋久, 糸口 聡, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2010, 化学工学会 研究発表講演要旨集, 2010(0) (0), 3 - 3, Japanese

  • 多孔性セラミックス系分離膜の分子シミュレーション
    吉岡 朋久
    May 2009, 分離技術, 39(3) (3), 137 - 145, Japanese
    [Invited]
    Introduction scientific journal

  • 中筋 雄大, 吉岡 朋久, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2009, 化学工学会 研究発表講演要旨集, 2009(0) (0), 640 - 640, Japanese

  • 金指 正言, 矢田 和也, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2009, 化学工学会 研究発表講演要旨集, 2009(0) (0), 659 - 659, Japanese

  • 中田 章博, 吉岡 朋久, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2009, 化学工学会 研究発表講演要旨集, 2009(0) (0), 663 - 663, Japanese

  • 糸口 聡, 吉岡 朋久, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2009, 化学工学会 研究発表講演要旨集, 2009(0) (0), 187 - 187, Japanese

  • 佐々木 明史, 吉岡 朋久, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2009, 化学工学会 研究発表講演要旨集, 2009(0) (0), 188 - 188, Japanese

  • 金指 正言, 山本 章, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2009, 化学工学会 研究発表講演要旨集, 2009(0) (0), 189 - 189, Japanese

  • 吉岡 朋久, 岡 勇輔, 都留 稔了
    公益社団法人 化学工学会, 2008, 化学工学会 研究発表講演要旨集, 2008(0) (0), 130 - 130, Japanese

  • 都留 稔了, 吉野 孝, 吉岡 朋久
    公益社団法人 化学工学会, 2008, 化学工学会 研究発表講演要旨集, 2008(0) (0), 213 - 213, Japanese

  • 金指 正言, 矢田 和也, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2008, 化学工学会 研究発表講演要旨集, 2008(0) (0), 824 - 824, Japanese

  • 中田 章博, 吉岡 朋久, 金指 正言, 都留 稔了
    公益社団法人 化学工学会, 2008, 化学工学会 研究発表講演要旨集, 2008(0) (0), 833 - 833, Japanese

  • 岡鼻 香緒理, 上西 理玄, 金指 正言, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2008, 化学工学会 研究発表講演要旨集, 2008(0) (0), 837 - 837, Japanese

  • YOSHIOKA Tomohisa
    Applications of molecular simulation to studies of gas permeation and separation through microporous inorganic membranes are reviewed. Porous inorganic membranes have chemical and thermal stability, and they are expected to be used for highly selective separation processes of several molecular mixtures. In order to adequately design those membranes and to decide effective operation conditions, it is important to understand gas permeation and separation mechanisms in ultra-microporoues on membranes from a microscopic viewpoint. A boundary driven nonequilibrium molecular dynamics (NEMD) technique, which enables us to easily simulate a non-equilibrium state permeation, is a useful tool for the understanding of gas permeation and separation phenomena in the scale of molecules. Many papers have been presented for development of molecular simulation techniques and their application to gas permeation and separation simulations on mainly three types of microporous inorganic membranes, zeolite, amorphous silica and carbon membranes. Ideal membrane performance is successfully predicted by using molecular simulations qualitatively, while structural and physical chemical adequacy of membrane model is important to reproduce membrane performance observed experimentally for real membranes. Further development of molecular simulation studies for microporous inorganic membranes would bring about more precise predictions of gas permeation and separation properties.
    THE MEMBRANE SOCIETY OF JAPAN, Mar. 2007, MEMBRANE, 32(2) (2), 71 - 79, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • 吉岡 朋久, 安本 章紀, 淺枝 正司, 都留 稔了
    公益社団法人 化学工学会, 2007, 化学工学会 研究発表講演要旨集, 2007(0) (0), 797 - 797, Japanese

  • メチルシクロヘキサンのための触媒膜型反応器の開発
    矢田 和也, 都留 稔了, 吉岡 朋久
    公益社団法人 化学工学会, 2007, 化学工学会 研究発表講演要旨集, 2007(0) (0), 1264 - 1264, Japanese

  • バイモーダル構造を有するシリカ触媒膜によるメタン水蒸気改質膜型反応特性
    森田 辰徳, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2007, 化学工学会 研究発表講演要旨集, 2007(0) (0), 1265 - 1265, Japanese

  • 小川 和久, 都留 稔了, 吉岡 朋久
    公益社団法人 化学工学会, 2007, 化学工学会 研究発表講演要旨集, 2007(0) (0), 598 - 598, Japanese

  • 吉野 孝, 吉岡 朋久, 浅枝 正司, 都留 稔了
    公益社団法人 化学工学会, 2006, 化学工学会 研究発表講演要旨集, 2006(0) (0), 347 - 347, Japanese

  • 森田 辰徳, 新谷 博昭, 吉岡 朋久, 浅枝 正司, 都留 稔了
    公益社団法人 化学工学会, 2006, 化学工学会 研究発表講演要旨集, 2006(0) (0), 349 - 349, Japanese

  • 伊木 亮祐, 吉岡 朋久, 都留 稔了, 浅枝 正司
    公益社団法人 化学工学会, 2006, 化学工学会 研究発表講演要旨集, 2006(0) (0), 362 - 362, Japanese

  • 尾崎 隆幸, 吉岡 朋久, 都留 稔了
    公益社団法人 化学工学会, 2006, 化学工学会 研究発表講演要旨集, 2006(0) (0), 666 - 666, Japanese

  • TSURU Toshinori, TANAKA Katsuyuki, YOSHIOKA Tomohisa, ASAEDA Masashi
    THE MEMBRANE SOCIETY OF JAPAN, 01 Nov. 2005, MEMBRANE, 30(6) (6), 339 - 343, Japanese

  • YOSHIOKA Tomohisa
    THE MEMBRANE SOCIETY OF JAPAN, Jul. 2005, MEMBRANE, 30(4) (4), 210 - 218, Japanese
    [Invited]
    Introduction scientific journal

  • 柴田 慎治, 都留 稔了, 吉岡 朋久, 浅枝 正司
    公益社団法人 化学工学会, 2005, 化学工学会 研究発表講演要旨集, 2005(0) (0), 344 - 344, Japanese

  • 吉岡 朋久, 田中 潤平, 都留 稔了, 淺枝 正司
    公益社団法人 化学工学会, 2005, 化学工学会 研究発表講演要旨集, 2005(0) (0), 357 - 357, Japanese

  • リン含有チタニア複合膜を用いた燃料電池膜システムの開発と発電特性
    八木 健一, 都留 稔了, 吉岡 朋久, 浅枝 正司
    公益社団法人 化学工学会, 2005, 化学工学会 研究発表講演要旨集, 2005(0) (0), 1041 - 1041, Japanese

  • 多孔性セラミック膜における有機溶媒系ナノ濾過特性
    成田 正範, 品川 亮, 都留 稔了, 吉岡 朋久, 浅枝 正司
    公益社団法人 化学工学会, 2005, 化学工学会 研究発表講演要旨集, 2005(0) (0), 587 - 587, Japanese

  • MD法による多孔性シリカ膜の緻密相におけるガス透過シミュレーション
    安本 章紀, 吉岡 朋久, 都留 稔了, 浅枝 正司
    公益社団法人 化学工学会, 2005, 化学工学会 研究発表講演要旨集, 2005(0) (0), 636 - 636, Japanese

  • 凝縮性気体のミクロ孔充填相透過モデルによるin-situサブナノ膜細孔径分布評価
    吉岡 朋久, 田中 潤平, 都留 稔了, 淺枝 正司
    公益社団法人 化学工学会, 2005, 化学工学会 研究発表講演要旨集, 2005(0) (0), 637 - 637, Japanese

  • バイモーダル触媒構造を有する水素選択透過性シリカ膜を用いたメタン改質反応
    新谷 博昭, 都留 稔了, 吉岡 朋久, 浅枝 正司
    公益社団法人 化学工学会, 2005, 化学工学会 研究発表講演要旨集, 2005(0) (0), 937 - 937, Japanese

  • YOSHIOKA Tomohisa
    THE MEMBRANE SOCIETY OF JAPAN, Jan. 2005, MEMBRANE, 30(1) (1), 29 - 37, Japanese
    [Refereed][Invited]
    Introduction scientific journal

  • Yoshioka Tomohisa, Tanaka Junpei, Tusru Toshinori, Asaeda Masashi
    Non-equilibrium molecular dynamics simulations of condensable vapor permeation and separation of condensable and non-condensable gas mixtures through a sub-nano scale pore were conducted on a virtual amorphous silica membrane which was prepared by the melt-quench procedures. Concerning the permeation properties of ethane-like LJ particle through a pore of 8 &Aring; in diameter, a surface diffusion-like temperature dependency was observed at relatively high temperature region (400-800 K), while around room temperatures, the permeance decreased with decreasing temperature. The permeances of non-condensable nitrogen-like particle, which has smaller affinity with the pore surface than ethane, was smaller than those of ethane and the Knudsen or surface diffusion-like temperature dependency curve could be seen. In simulations of separation for ethane/nitrogen binary mixtures at 260 K, a temperature below the critical temperature (<I>T<SUB>C</SUB></I>) of actual ethane, the concentration dependency of ethane permeance showed an almost flat curve in low concentration (partial pressure) region, and at a higher specific concentration, the permeance largely decreased. The permeances of nitrogen were smaller at any partial pressure conditions compared with those observed in single nitrogen gas permeation simulations. Especially at a large partial pressure of ethane, the permeance of nitrogen became very small. This fact indicates a condensable component that has larger interaction with the pore surface could obstruct the transport of a non-condensable one to decrease its permeance. Above mentioned results suggest that the micropore filling of condensable gases could occur in a micropore at temperatures below <I>T<SUB>C</SUB></I> and at sufficiently high pressures, and this phenomenon would play an important role in determining the separation performance of these gases through a micropore.
    公益社団法人 化学工学会, 2004, Asian Pacific Confederation of Chemical Engineering congress program and abstracts, 2004(0) (0), 741 - 741, English
    Summary international conference

  • Stability of Ni-doped Silica Membranes for H2 Separation at High Temperature
    2004, Transactions of the Materials Research Society of Japan, 29(7) (7), 3267 - 3270

  • Molecular Dynamics Simulation of Transport and Separation of Condensable and Non-condensable Gas Mixtures through Microporous Silica Membranes
    2004, Proc. 8th Intern. Conf. Inorganic Membranes, 242 - 245, English
    Summary international conference

  • Stability of Ni-doped Silica Membranes for H2 Separation at High Temperature
    2004, Transactions of the Materials Research Society of Japan, 29(7) (7), 3267 - 3270

  • 吉岡 朋久, 都留 稔了, 淺枝 正司
    公益社団法人 化学工学会, 2003, 化学工学会 研究発表講演要旨集, 2003(0) (0), 534 - 534, Japanese

  • 山口 浩司, 都留 稔了, 吉岡 朋久, 浅枝 正司
    公益社団法人 化学工学会, 2003, 化学工学会 研究発表講演要旨集, 2003(0) (0), 541 - 541, Japanese

  • 柴田 慎治, 都留 稔了, 吉岡 朋久, 浅枝 正司
    公益社団法人 化学工学会, 2003, 化学工学会 研究発表講演要旨集, 2003(0) (0), 564 - 564, Japanese

  • Gas permeation characteristics and stability of composite silica-metal oxide membranes
    M Asaeda, M Kanezashi, T Yoshioka, T Tsuru
    In order to improve the stability of silica membranes against water (vapor) some metal oxides were added to silica to obtain composite silica-metal oxide membranes by the sol-gel techniques. A Ni-doped silica membrane (Ni/Si=1/2) fired at 500degreesC showed a relatively large permeance of 1.5x 10(-5) [m(3)(STp)/(m(2) skPa)] with selectivity of 350 (H-2/CH4), 4200 (H-2/SF6) at 200degreesC and 100 (CO2/CH4) at 35degreesC. After leaving the membrane in humid air (RH: 60%, 40degreesC) for 70 days, the permeance of H-2 decreased by about 50% but the selectivity was improved to 930 for H-2/CH4. And little change was observed in the activation energy for H-2 permeation, while under the same conditions a silica membrane showed a quite large change in the activation energy from 3.1kJ/mol to 14kJ/mol, There is a possibility that metal oxides added to silica help prevent the densification of silica networks through which hydrogen and helium molecules can permeate.
    MATERIALS RESEARCH SOCIETY, 2003, MEMBRANES-PREPARATION, PROPERTIES AND APPLICATIONS, 752, 213 - 218, English

  • 超微細孔を有する多孔性シリカ膜におけるガス透過機構
    吉岡朋久
    分離技術会, 2001, 分離技術, 31(5) (5), 278 - 285, Japanese
    [Invited]

  • Molecular dynamics simulation of gas permeation in microporous silica membranes
    1999, Proc. Intern. Congress on Membranes and Membrane Processes, 43, English
    Summary international conference

  • Permeation mechanism of inorganic gases in ultra-microporous silica membranes
    YOSHIOKA T.
    1998, Proceedings of the Fifth International Conference on Inorganic Membranes, 120 - 123, English
    Introduction scientific journal

  • Observation of interface curvature of capillary condensed phase in slit-shaped nano pore with a new MD simulation method
    1997, Characterisation of porous solids IV, 413 - 420, English
    Summary international conference

  • Non-uniform curvature model for condensation in cylindrical nano pores
    1996, Proc. 4th Intern. Symposium on the Characterization of Porous Solids, English
    Summary international conference

■ Books And Other Publications
  • マテリアルズ・インフォマティクスによる材料開発と活用集
    YOSHIOKA TOMOHISA
    Others, 技術情報協会, Jan. 2019, Japanese, ISBN: 9784861047633
    Scholarly book

  • Current Trends and Future Developments on (Bio-) Membranes Silica Membranes: Preparation, Modelling, Application, and Commercialization, Chapter 5: Molecular dynamic (MD) simulation of silica membranes
    YOSHIOKA TOMOHISA
    Others, Academic Press, Elsevier, Aug. 2017, English
    Scholarly book

■ Lectures, oral presentations, etc.
  • 有機溶媒分離の性能向上を目指したポリアミド複合膜の開発
    阿波治宏樹, LIU Cuijing, 新谷卓司, 松山秀人
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • TiO2-ZrO2-有機キレート配位子（OCL）複合膜の有機溶剤ナノろ過特性
    家迫遼介, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • 圧力支援法によるMoS2ナノシート積層膜の作製とナノろ過特性の評価
    釆尾崇哉, 中川敬三, Shik Chi Edman Tsang, 新谷卓司, 神尾英治, 松山秀人, 吉岡朋久
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • 有機キレート配位子を用いたTiO2-SiO2膜の作製と気体透過特性評価
    安成竜輝, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • 分子シミュレーションを用いたポリアミド膜に対する低分子量物質のファウリング機構解明
    川端優希, 吉岡朋久, 中川敬三, 新谷卓司, 松山秀人
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • シリカ担持触媒を用いたMCH脱水素反応および触媒膜の作製
    山田 雛乃, 中川敬三, 新谷卓司, 神尾英治, 松山秀人, 吉岡朋久
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • 分子動力学シミュレーションを用いた酸化グラフェン積層膜の透過機構解明
    安井健悟, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • 合成有機化合物の分離精製のための新規NF膜及びプロセス開発
    角南俊輔, 新谷卓司, 中川敬三, 佐々木雄史, 松山秀人, 吉岡朋久
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • FOファウリングでの透水挙動に及ぼすファウラント組成の影響
    松葉真由, 中川敬三, 新谷卓司, 吉岡朋久, 長谷川進, 佐々木雄史, 神尾英治, 松山秀人
    化学工学会第85年会, Mar. 2020, Japanese, 化学工学会, 大阪府, Domestic conference
    Poster presentation

  • 分子動力学法によるゼオライト膜における分離透過メカニズム解析と高性能膜の設計
    植田 敬文, 吉岡 朋久, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人
    第22回化学工学会学生発表会(岡山大会), 2020, Japanese, 化学工学会, 岡山県, Domestic conference
    Oral presentation

  • アミン系架橋剤を利用した積層型酸化グラフェン膜の作製と有機溶剤ナノろ過特性の評価
    牛尾 海, 中川 敬三, 吉岡 朋久, 新谷 卓司, 神尾 英治, 松山 秀人
    第22回化学工学会学生発表会(岡山大会), 2020, Japanese, 化学工学会, 岡山県, Domestic conference
    Oral presentation

  • 界面重縮合反応を用いたフッ素含有ポリアミド膜の作製と水及び有機溶剤の透過性評価
    串田 航, 新谷 卓司, 中川 敬三, 佐々木 雄史, 長谷川 進, 神尾 英治, 松山秀人
    第22回化学工学会学生発表会(岡山大会), 2020, Japanese, 化学工学会, 岡山県, Domestic conference
    Oral presentation

  • 有機キレート配位子を利用したチタニア-ジルコニア複合膜の細孔径制御
    家迫 遼介, 吉岡 朋久, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人
    化学工学会姫路大会2019, Dec. 2019, Japanese, 化学工学会, 兵庫県, Domestic conference
    Oral presentation

  • 担持Pt触媒を用いたシリカ系触媒膜の作製とメチルシクロヘキサン脱水素反応の評価
    山田 雛乃, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人, 吉岡 朋久
    化学工学会姫路大会2019, Dec. 2019, Japanese, 化学工学会関西支部, 兵庫県, Domestic conference
    Oral presentation

  • 分子動力学シミュレーションを用いた酸化グラフェン積層膜の透過・分離機構の解明
    安井 健悟, 吉岡 朋久, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人
    化学工学会姫路大会2019, Dec. 2019, Japanese, 化学工学会関西支部, 兵庫県, Domestic conference
    Oral presentation

  • 二次成長法によるナノシート膜上へのCuBDC MOF膜の作製
    小野山真之, 中川敬三, 田中俊輔, 新谷卓司, 神尾英治, 松山秀人, 吉岡朋久
    膜シンポジウム2019, Nov. 2019, Japanese, 日本膜学会, 大阪府, Domestic conference
    Poster presentation

  • Pt含有酸化グラフェン積層膜の作製とp-ニトロフェノール還元反応における触媒活性評価
    塩野颯斗, 中川敬三, 新谷卓司, 神尾英治, 松山秀人, 吉岡朋久
    膜シンポジウム2019, Nov. 2019, Japanese, 日本膜学会, 大阪府, Domestic conference
    Poster presentation

  • MoS2ナノシート積層膜の作製と加圧処理が及ぼす膜性能への影響
    釆尾崇哉, 中川敬三, Shik Chi Edman Tsang, 新谷卓司, 神尾英治, 松山秀人, 吉岡朋久
    膜シンポジウム2019, Nov. 2019, Japanese, 日本膜学会, 大阪府, Domestic conference
    Poster presentation

  • 界面活性剤の分離精製における新規NF膜及びプロセス開発
    角南俊輔, 新谷卓司, 中川敬三, 佐々木雄史, 松山秀人, 吉岡朋久
    膜シンポジウム2019, Nov. 2019, Japanese, 日本膜学会, 大阪府, Domestic conference
    Poster presentation

  • 分子動力学法による有機溶剤のTiO2膜ナノ細孔における透過現象の解析
    小原 侑也, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    膜シンポジウム2019, Nov. 2019, Japanese, 日本膜学会, 大阪府, Domestic conference
    Poster presentation

  • 芳香族系有機キレート剤を用いたTiO2-ZrO2複合ガス分離膜の作製と透過特性評価
    橘 高志, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    膜シンポジウム2019, Nov. 2019, Japanese, 日本膜学会, 大阪府, Domestic conference
    Poster presentation

  • 層間が架橋された酸化グラフェン積層膜の開発
    牛尾海, 中川敬三, 吉岡朋久, 新谷卓司, 神尾英治, 松山秀人
    第18回無機膜研究会「プロセス開発に向けた無機膜研究の基礎から応用」, Oct. 2019, Japanese, 化学工学会分離プロセス部会膜工学分科会化学工学会反応工学部会反応分離分科会, 岐阜県, Domestic conference
    Poster presentation

  • 分子動力学法によるMFI型ゼオライト膜の吸着・拡散性の評価
    植田敬文, 吉岡朋久, 中川敬三, 新谷卓司, 松山秀人
    第18回無機膜研究会「プロセス開発に向けた無機膜研究の基礎から応用」, Oct. 2019, Japanese, 化学工学会分離プロセス部会膜工学分科会化学工学会反応工学部会反応分離分科会, 岐阜県, Domestic conference
    Poster presentation

  • 水処理膜における膜ファウリングメカニズムの解明
    松葉真由, 中川敬三, 新谷卓司, 吉岡朋久, 佐々木雄史, 神尾英治, 松山秀人
    第18回無機膜研究会「プロセス開発に向けた無機膜研究の基礎から応用」, Oct. 2019, Japanese, 化学工学会分離プロセス部会膜工学分科会化学工学会反応工学部会反応分離分科会, 岐阜県, Domestic conference
    Poster presentation

  • 有機キレート配位子を用いたSiO2-TiO2複合膜材料の開発
    安成竜輝, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    第18回無機膜研究会「プロセス開発に向けた無機膜研究の基礎から応用」, Oct. 2019, Japanese, 化学工学会分離プロセス部会膜工学分科会化学工学会反応工学部会反応分離分科会, 岐阜県, Domestic conference
    Poster presentation

  • Development of novel organic solvent resistant RO membrane
    Ayane HIROSUE, Takuji SHINTANI, Keizo NAKAGAWA, Yuji SASAKI, Susumu HASEGAWA, Tomohisa YOSHIOKA, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Molecular dynamics simulation of organic solvent permeation in nanoporous TiO2 membranes
    Yuya OHARA, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Molecular dynamics study of CO3-absorbed ionic liquid structures and diffusivity
    Yusaku EBINA, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA, Koseki SUGIYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Fabrication of CuBDC MOF nanosheet laminated membrane by suction filtration
    Masayuki ONOYAMA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA, Tomohisa YOSHIOKA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Improvement in pressure resistance by structure control of porous polyketone membrane for pressure retarded osmosis
    Kiyohito UCHIDA, Keizo NAKAGAWA, Takuji SHINTANI, Tomohisa YOSHIOKA, Susumu HASEGAWA, Yuji SASAKI, Eiji KAMIO, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Fabrication of graphene oxide membranes on porous α-alumina support by pressure assisted method
    Hayato SHIONO, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA, Tomohisa YOSHIOKA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Gas permeation properties of TiO2-ZrO3-Gallate nanocomposite porous membranes,
    Takashi TACHIBANA, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Evaluation of pore size distribution of microporous ceramic membranes by micropore ?lling phase permeation method using various condensable gases
    Yu OGAWA, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji. SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Effect of composite membrane structure on performance of graphene oxide/metal oxide nanosheets composite membranes
    Misato KUNIMATSU, Keizo NAKAGAWA, Tomohisa YOSHIOKA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Poster presentation

  • Fabrication of niobium oxide based nanosheet membranes and their nanofiltration performance in water and alcohol
    Keizo NAKAGAWA, Misato KUNIMATSU, Tomohisa YOSHIOKA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Oral presentation

  • Molecular dynamics simulation of FO/RO water permeation in amphotericin B water channel
    Tomohisa YOSHIOKA, Keisuke Kotaka, Keizo NAKAGAWA, Takuji SHINTANI, Takahiro KAWAKATSU, Yu FUJIMURA, Hao-Chen WU, Hideto MATSUYAMA
    The 18th Asian Pacific Confederation of Chemical Engineering Congress, Sep. 2019, English, The Society of Chemical Engineers, Japan, Sapporo, Japan, International conference
    Oral presentation

  • Development of the novel nanofiltration membrane for separating divalent cation and divalent anion in the electrodialysis drainage
    Takuji SHINTANI, Shinnosuke HAMADA, Kazuki AKAMATSU, Tomoki TAKAHASHI, Keizo NAKAGAWA, Hideto MATSUYAMA, Tomohisa YOSHIOKA
    AMS12 (12th Conference of the Aseanian Membrane Society), Jul. 2019, English, Aseanian Membrane Society, Jeju, Korea, International conference
    Poster presentation

  • 炭素電極を用いた容量性脱イオンおよび膜容量性脱イオン
    川端優希, 塩冶一馬, 中川敬三, 新谷卓司, 吉岡朋久, 清野竜太郎
    分離技術会年会2019, May 2019, Japanese, The Society of Separation Process Engineering, Japan, Nagoya Institute of Technology, Nagoya, Domestic conference
    Poster presentation

  • ニオブ酸化物ナノシート/酸化グラフェン複合型積層膜の作製とナノろ過特性の評価
    國松美里, 中川敬三, 吉岡朋久, 新谷卓司, 神尾英治, 松山秀人
    分離技術会年会2019, May 2019, Japanese, The Society of Separation Process Engineering, Japan, Nagoya Institute of Technology, Nagoya, Domestic conference
    Poster presentation

  • ミクロ孔充填相透過法を用いた多孔性セラミック膜の細孔径分布評価
    小川祐生, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    分離技術会年会2019, May 2019, Japanese, The Society of Separation Process Engineering, Japan, Nagoya Institute of Technology, Nagoya, Domestic conference
    Oral presentation

  • 活性炭素繊維電極を用いた膜容量性脱イオン
    川端優希, 塩冶一馬, 中川敬三, 新谷卓司, 吉岡朋久, 清野竜太郎
    日本膜学会第41年会, 2019, Japanese, The Membrane Society of Japan, Waseda Univeristy, Tokyo, Domestic conference
    Poster presentation

  • 有機キレート配位子を鋳型にしたチタニア－ジルコニア複合ナノろ過膜の有機溶剤透過・分画特性評価
    家迫遼介, 吉岡朋久, 中川敬三, 新谷卓司, 神尾英治, 松山秀人
    日本膜学会第41年会, 2019, Japanese, The Membrane Society of Japan, Waseda Univeristy, Tokyo, Domestic conference
    Poster presentation

  • 架橋型酸化グラフェン積層膜および酸化グラフェン/ニオブ酸化物ナノシート複合積層膜の作製とナノろ過性能の比較検討
    中川敬三, 國松美里, 荒屋伸太朗, 吉岡朋久, 新谷卓司, 神尾英治, 松山秀人
    日本膜学会第41年会, 2019, Japanese, The Membrane Society of Japan, Waseda Univeristy, Tokyo, Domestic conference
    Oral presentation

  • 有機溶媒耐性を有する新規PA-TFC膜の開発
    廣末 絢音, SHINTANI TAKUJI, NAKAGAWA KEIZO, SASAKI YUJI, HASEGAWA Susumu, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • 有機キレート配位子を鋳型とする多孔性TiO2-ZrO2ナノろ過膜の細孔径評価と分画特性
    YOSHIOKA TOMOHISA, 貞 佑樹, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Oral presentation

  • 分子シミュレーションによるイオン液体中の二酸化炭素拡散性評価
    海老名 祐作, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • 電気透析排水から2価陽イオンと2価陰イオンを選択分離する新規ナノ濾過膜の開発
    濵田 慎之介, SHINTANI TAKUJI, 赤松 憲樹, NAKAGAWA KEIZO, SASAKI YUJI, HASEGAWA Susumu, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    日本海水学会若手会第10回学生研究発表会, Mar. 2019, Japanese, 日本海水学会若手会, 旧佐世保鎮守府凱旋記念館, Domestic conference
    Poster presentation

  • Molecular simulation of water permeation in water channel membranes
    YOSHIOKA TOMOHISA
    日本化学会 第99春季年会, Mar. 2019, Japanese, 日本化学会, 甲南大学, Domestic conference
    [Invited]
    Invited oral presentation

  • 高分子膜を利用した正浸透法における膜ファウリング特性
    岡本 将尚, NAKAGAWA KEIZO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, HASEGAWA Susumu, SASAKI YUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • 計算機支援による水および有機溶剤のナノ空間における分子拡散現象の解析
    小原 侑也, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, MATSUYAMA HIDETO
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • 吸引ろ過法を利用したCuBDC MOFナノシート積層膜の作製
    小野山 真之, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • 圧力支援法を用いた多孔質アルミナ管上への酸化グラフェン積層膜の作製
    塩野 颯斗, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • ポリケトン支持膜の構造制御による耐圧性と正浸透膜における透水性への影響
    内田 聖人, NAKAGAWA KEIZO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, 長谷川 進, SASAKI YUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • チタニア・ジルコニア複合ナノろ過膜の作製と有機溶剤透過性評価
    家迫 遼介, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第21回化学工学会学生発表会(京都大会), Mar. 2019, Japanese, 公益社団法人化学工学会, 京都, Domestic conference
    Oral presentation

  • アルカノールアミンで架橋されたGO積層膜の透水性能と塩阻止性
    荒屋 伸太朗, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • TiO2-ZrO2-Gallateナノ複合多孔膜の細孔構造と気体透過特性評価
    橘 高志, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第84.年会, Mar. 2019, Japanese, 化学工学会, 芝浦工業大学, Domestic conference
    Poster presentation

  • MoS2ナノシートを用いた積層膜の作製と製膜法による積層構造の変化
    釆尾 崇哉, NAKAGAWA KEIZO, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第21回化学工学会学生発表会(京都大会)+H31:K31, Mar. 2019, Japanese, 公益社団法人化学工学会, 京都, Domestic conference
    Oral presentation

  • A molecular simulation investigation of structural properties and transport performance of artificial water channel
    WU HAO CHEN, YOSHIOKA TOMOHISA, 都留 稔, SAEKI DAISUKE, MATSUYAMA HIDETO
    化学工学会第84年会, Mar. 2019, Japanese, 化学工学会, 東京, Domestic conference
    Poster presentation

  • Preparation of polyamide thin film composite forward osmosis membranes using hydrophilic PVDF and PSF hollow fibers modified by PVA perdiffusion method
    Youhei YABUNO, K. Mihara, K. Komatsu, S. Shimamura K. Nakagawa, T. Shintani, H. Matsuyama, T. Yoshioka
    AMS12 (12th Conference of the Aseanian Membrane Society), Jul. 2019, English, Aseanian Membrane Society, Jeju, Korea, International conference
    Oral presentation

  • The nanofiltration property of stacked nanosheet composite membrane incorporating graphene oxide into metal oxide membrane
    Misato KUNIMATSU, Keizo NAKAGAWA, Tomohisa YOSHIOKA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    AMS12 (12th Conference of the Aseanian Membrane Society), Jul. 2019, English, Aseanian Membrane Society, Jeju, Korea, International conference
    Poster presentation

  • Evaluation of Pore Size Distribution of Microporous Ceramic Membranes by Gas Permeation and Micropore Filling Phase Permeation Method
    Yu OGAWA, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    AMS12 (12th Conference of the Aseanian Membrane Society), Jul. 2019, English, Aseanian Membrane Society, Jeju, Korea, International conference
    Poster presentation

  • Fabrication of forward osmosis membrane with improved pressure resistance using structure-controlled porous polyketone support membrane
    Keizo NAKAGAWA, K. Uchida, J. Wu, T. Shintani, T. Yoshioka, L. F. Fang, S. Hasegawa, Y. Sasaki, E. Kamio, H. Matsuyama
    AMS12 (12th Conference of the Aseanian Membrane Society), Jul. 2019, English, Aseanian Membrane Society, Jeju, Korea, International conference
    Poster presentation

  • Nanofiltration characteristics of organic chelate ligand (OCL)-templated microporous TiO2-ZrO2 membranes
    Tomohisa YOSHIOKA, Yuki SADA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    AMS12 (12th Conference of the Aseanian Membrane Society), Jul. 2019, English, Aseanian Membrane Society, Jeju, Korea, International conference
    Oral presentation

  • 分子シミュレーションによるAmphotericin B-Ergosterolとポリアミド膜のFO透水性能比較Comparison of Forward Osmosis Water Permeability of Amphotericin B-Ergosterol and Polyamide Membrane by Molecular Simulation
    Keisuke Kotaka, Tomohisa Yoshioka, Keizo Nakagawa, Takuji Shintani, Takahiro Kawakatsu, Yu Fujimura, WU HAO CHEN, Daisuke. Saeki, Hideto Matsuyama
    第２８回日本MRS年次大会, Dec. 2018, Japanese, 北九州国際会議場・西日本総合展示場, Domestic conference
    Poster presentation

  • ポリケトン支持膜のアミン修飾による膜構造や耐圧性の影響
    内田 聖人, NAKAGAWA KEIZO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, HASEGAWA Susumu, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会 中国四国支部;関西支部合同徳島大会, Dec. 2018, Japanese, 徳島大学, Domestic conference
    Oral presentation

  • ガス透過法およびミクロ孔充填相透過法を用いた多孔性セラミック膜の細孔構造評価Characterization of Porous Structures of Microporous Ceramic Membranes by Gas Permeation and Micropore Filling Phase Permeation Method
    Yuu Ogawa, Tomohisa Yoshioka, Keizo Nakagawa, Takuji Shintani, Eiji Kamio, Hideto Matsuyama
    第２８回日本MRS年次大会, Dec. 2018, Japanese, 北九州国際会議場・西日本総合展示場, Domestic conference
    Poster presentation

  • TiO2-ZrO2-有機キレート配位子複合ガス分離膜の開発Development of TiO2-ZrO2-organic chelate ligand composite membranes for gas separation
    Tomohisa Yoshioka, Shoichi Hirai, Keizo Nakagawa, Takuji Shintani, Eiji Kamio, Hideto Matsuyama
    第２８回日本MRS年次大会, Dec. 2018, Japanese, 北九州国際会議場・西日本総合展示場, Domestic conference
    Oral presentation

  • Fabrication of cross-linked graphene oxide membranes by using alkanolamine
    Shintaro Araya, Keizo Nakagawa, Tomohisa Yoshioka, Takuji Shintani, Eiji Kamio, Hideto Matsuyama
    第２８回日本MRS年次大会, Dec. 2018, Japanese, 北九州国際会議場・西日本総合展示場, Domestic conference
    Poster presentation

  • 有機キレート配位子を鋳型に用いたTiO2-ZrO2複合NF膜の分離特性
    貞 佑樹, YOSHIOKA TOMOHISA, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人
    膜シンポジウム2018, Nov. 2018, Japanese, 日本膜学会, 神戸市, Domestic conference
    Poster presentation

  • 分子シミュレーションによるポリイミド膜構造の規則性が気体透過特性に及ぼす影響評価
    片山 基輔, YOSHIOKA TOMOHISA, 中川 敬三, 新谷 卓司, 藤原 寛, 神尾 英治, 松山 秀人
    膜シンポジウム2018, Nov. 2018, Japanese, 神戸市, Domestic conference
    Poster presentation

  • 非平衡分子動力学シミュレーションによるTiO2 ナノ細孔内液相透過現象のモデリング
    YOSHIOKA TOMOHISA, 鈴木悠太, 中川 敬三, 新谷 卓司, 松山 秀人
    膜シンポジウム2018, Nov. 2018, Japanese, 日本膜学会, 神戸市, Domestic conference
    Oral presentation

  • 電気透析排水中の2価陽イオンと2価陰イオンを高度に選択分離する新規ナノ濾過膜の開発と性能評価
    濵田 慎之介, 新谷 卓司, 赤松 憲樹, 中川 敬三, 長谷川 進, 松山 秀人, YOSHIOKA TOMOHISA
    膜シンポジウム2018, Nov. 2018, Japanese, 日本膜学会, 神戸市, Domestic conference
    Poster presentation

  • 中空シリカ担持Pt触媒を用いたシリカ系分離膜の作製とメチルシクロヘキサン脱水素反応の評価
    岩崎 太幹, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    膜シンポジウム2018, Nov. 2018, Japanese, 神戸, Domestic conference
    Poster presentation

  • 多孔性セラミック分離膜と分子シミュレーション
    YOSHIOKA TOMOHISA
    分離技術会 第14回東海地区分離技術講演会, Nov. 2018, Japanese, 分離技術会, 名古屋工業大学, Domestic conference
    Public discourse

  • 浸透圧補助型低圧逆浸透法における塩水濃縮に及ぼす各種操作条件の影響
    東郷 範弘, NAKAGAWA KEIZO, 高橋 智輝, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KAMIO EIJI, MATSUYAMA HIDETO
    膜シンポジウム2018, Nov. 2018, Japanese, 神戸, Domestic conference
    Poster presentation

  • ニオブ酸化物ナノシート積層型分離膜の作製―ナノシート調製法が膜性能に及ぼす影響―
    中川 敬三, 世良友宏, 國松美里, YOSHIOKA TOMOHISA, 新谷 卓司, 神尾 英治, 松山 秀人
    膜シンポジウム2018, Nov. 2018, Japanese, 日本膜学会, 神戸市, Domestic conference
    Oral presentation

  • ニオブ酸化物/酸化グラフェン複合ナノシート膜における積層構造と透水性の関係
    國松 美里, NAKAGAWA KEIZO, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    膜シンポジウム2018, Nov. 2018, Japanese, 神戸, Domestic conference
    Poster presentation

  • アルカノールアミンを利用した架橋型酸化グラフェン積層膜の作製
    荒屋 伸太朗, NAKAGAWA KEIZO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KAMIO EIJI, MATSUYAMA HIDETO
    膜シンポジウム2018, Nov. 2018, Japanese, 神戸, Domestic conference
    Poster presentation

  • Fabrication of Silica-based Catalytic Membrane including Pt CatalystsEncapsulated in Hollow Silica Nanotubes
    Daiki Iwasaki, Keizo Nakagawa, Takuji Shintani, Eiji Kamio, Hideto Matsuyama, Tomohisa Yoshioka
    6th International Workshop on Process Intensification （IWPI 2018）, Nov. 2018, English, National Taiwan University, International conference
    Oral presentation

  • Enhanced Membrane Filtration Performance of Stacked Niobate Nanosheet Membranes by The Addition of Graphene Oxide
    Nakagawa Keizo, Kunimatsu Misato, Araya Shintaro, Yoshioka Tomohisa, Shintani Takuji, Kamio Eiji, Matsuyama Hideto
    6th International Workshop on Process Intensification (IWPI 2018), Nov. 2018, English, National Taiwan University, International conference
    [Invited]
    Invited oral presentation

  • A molecular simulation on structural properties and performance investigation of artificial water channels
    WU HAO CHEN, Tomohisa Yoshioka, Toshinori Tsuru, Hideto Matsuyama
    膜シンポジウム2018, Nov. 2018, English, 神戸, Domestic conference
    Oral presentation

  • 有機溶剤分離のためのTiO2-ZrO2複合膜の細孔径制御と性能評価
    家迫 遼介, YOSHIOKA TOMOHISA, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人
    第17 回無機膜研究会, Oct. 2018, Japanese, 化学工学会分離プロセス部会膜工学分科会, 長野県駒ヶ根市, Domestic conference
    Poster presentation

  • 正浸透膜法の駆動溶液に用いる温度応答性イオン液体の会合挙動に関する検討
    栗栖 宏樹, TAKAHASHI TOMOKI, YOSHIOKA TOMOHISA, MATSUYAMA HIDETO
    第5回海水・生活・化学連携シンポジウム, Oct. 2018, Japanese, 日本海水学会若手会, 宮城県石巻市, Domestic conference
    Poster presentation

  • 化学的に剥離されたMoS2ナノシートによる積層膜の作製
    釆尾 崇哉, 中川 敬三, YOSHIOKA TOMOHISA, 新谷 卓司, 神尾 英治, 松山 秀人
    第17 回無機膜研究会, Oct. 2018, Japanese, 化学工学会分離プロセス部会膜工学分科会, 長野県駒ヶ根市, Domestic conference
    Poster presentation

  • 「酸化チタンナノワイヤーおよびグラフェを利用した触媒膜の設計
    塩野 颯斗, 中川 敬三, 新谷 卓司, 神尾 英治, 松山秀人, YOSHIOKA TOMOHISA
    第17 回無機膜研究会, Oct. 2018, Japanese, 化学工学会分離プロセス部会膜工学分科会, 長野県駒ヶ根市, Domestic conference
    Poster presentation

  • TiO2-ZrO2-有機キレート複合材料の特性評価と気体分離膜への応用
    橘 高志, YOSHIOKA TOMOHISA, 中川 敬三, 新谷 司, 神尾 英治, 松山 秀人
    第17 回無機膜研究会, Oct. 2018, Japanese, 化学工学会分離プロセス部会膜工学分科会, 長野県駒ヶ根市, Domestic conference
    Poster presentation

  • 膜透過分子間相互作用を考慮した多孔性セラミック膜の細孔構造評価
    小川 祐生, YOSHIOKA TOMOHISA, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人
    化学工学会第50回秋季大会, Sep. 2018, Japanese, 化学工学会, 鹿児島市, Domestic conference
    Oral presentation

  • 中空糸膜モジュールを用いた浸透圧補助低圧逆浸透法による塩水濃縮と透水挙動解析
    東郷 範弘, 中川 敬三, 高橋 智輝, 新谷 卓司, YOSHIOKA TOMOHISA, 神尾 英治, 松山 秀人
    化学工学会第50回秋季大会, Sep. 2018, Japanese, 化学工学会, 鹿児島市, Domestic conference
    Oral presentation

  • 正浸透膜プロセスに用いる温度相転移物質の会合挙動が浸透圧に及ぼす影響
    栗栖 宏樹, TAKAHASHI TOMOKI, YOSHIOKA TOMOHISA, KAMIO EIJI, INADA ASUKA, MATSUYAMA HIDETO
    化学工学会第50回秋季大会, Sep. 2018, English, 鹿児島（鹿児島大学）, Domestic conference
    Oral presentation

  • 水分子共存下におけるシリカナノ粒子の高分子膜表面への付着挙動の分子動力学シミュレーション
    岡田 恵丞, YOSHIOKA TOMOHISA, 中川 敬三, 新谷 卓司, 松山 秀人, 藤村 侑, 川勝 孝博
    化学工学会第50回秋季大会, Sep. 2018, Japanese, 化学工学会, 鹿児島市, Domestic conference
    Oral presentation

  • ニオブ酸化物ナノシート積層膜のナノろ過特性に及ぼす酸化グラフェン複合化の効果
    國松 美里, 中川 敬三, YOSHIOKA TOMOHISA, 新谷 卓司, 神尾 英治, 松山 秀人
    化学工学会第50回秋季大会, Sep. 2018, Japanese, 化学工学会, 鹿児島市, Domestic conference
    Oral presentation

  • Pt内包シリカナノチューブ触媒を用いたメチルシクロヘキサン脱水素反応および触媒膜の作製
    岩崎 太幹, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人, YOSHIOKA TOMOHISA
    化学工学会第50回秋季大会, Sep. 2018, Japanese, 化学工学会, 鹿児島市, Domestic conference
    Oral presentation

  • ガス分離／液体分離への応用を目指した多孔性セラミック膜開発
    YOSHIOKA TOMOHISA
    新技術説明会, Aug. 2018, Japanese, JST, 東京都, Domestic conference
    Oral presentation

  • Molecular dynamics simulation study of polyamide membrane structures and RO/FO water permeation properties
    Yoshioka Tomohisa, Keisuke Kotaka, Keizo Nakagawa, Shintani Takuji, Kwakatsu Takahiro, Fujimura Yu, Wu Hao-Chen, Matsuyama Hideto
    The 11th Conference of Aseanian Membrane Society (AMS11), Jul. 2018, English, The Rydges Hotel, Brisbane Southbank, Australia, International conference
    Oral presentation

  • Gas permeation properties of microporous ceramic membranes;molecular simulation and in-situ characterizationof sub-nano porous structures
    Yoshioka Tomohisa
    8th International Symposium on Inorganic Membranes (ISIM8), Jul. 2018, English, The University of Queensland, Brisbane, Australia, International conference
    Nominated symposium

  • Fabrication of 2D Niobium Oxide/Graphene Oxide Nanosheet Composite Membranes for Nanofiltration
    Keizo NAKAGAWA, Misato KUNIMATSU, Daisuke SAEKI, Tomohisa YOSHIOKA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 11th Conference of Aseanian Membrane Society (AMS11), Jul. 2018, English, Aseanian Membrane Society, Brisbane (Australia), International conference
    Oral presentation

  • Development of polyamide thin-film composite membrane using novel porous support for organic solvent treatment
    Takuji SHINTANI, Yuki NAKAGAWA, Tomoki TAKAHASHI, Keizo NAKAGAWA, Hideto MATSUYAMA, Tomohisa YOSHIOKA
    The 11th Conference of Aseanian Membrane Society (AMS11), Jul. 2018, English, Aseanian Membrane Society, Brisbane (Australia), International conference
    Poster presentation

  • 酸化グラフェンの複合による金属酸化物ナノシート積層膜の膜性能向上
    國松 美里, NAKAGAWA Keizo, YOSHIOKA Tomohisa, SHINTANI Takuji, KAMIO Eiji, MATSUYAMA Hideto
    第７回JACI/GSCシンポジウム, Jun. 2018, Japanese, 新化学技術推進協会, 神戸市, Domestic conference
    Poster presentation

  • 気体透過法による多孔性無機膜のサブナノ細孔径分布評価と気体透過選択性の予測
    小川 祐生, YOSHIOKA TOMOHISA, NAKAGAWA Keizo, SHINTANI Takuji, KAMIO Eiji, MATSUYAMA Hideto
    第７回JACI/GSCシンポジウム, Jun. 2018, Japanese, 新化学技術推進協会, 神戸市, Domestic conference
    Poster presentation

  • Simulation and modeling of water permeation in TiO2 nanoporous membranes using non-equilibrium molecular dynamics
    Yoshioka Tomohisa, Suzuki Yuta, Keizo Nakagawa, Shintani Takuji, Kamio Eiji, Matsuyama Hideto, Tsuru Toshinori
    15th International Conference on Inorganic Membranes (ICIM-15)15th International Conference on Inorganic Membranes, Jun. 2018, English, The Westin Bellevue Dresden, Germany, International conference
    Oral presentation

  • 2D niobium oxide nanosheet membranes for water treatment: effects of nanosheet preparation methods on their membrane performances
    NAKAGAWA Keizo, SERA Tomohiro, KUNIMATSU Misato, Daisuke SAEKI, YOSHIOKA Tomohisa, SHINTANI Takuji, KAMIO Eiji, MATSUYAMA Hideto
    15th International Conference on Inorganic Membranes (ICIM2018), Jun. 2018, English, International conference
    Oral presentation

  • 有機キレート配位子を鋳型に用いた高透水性TiO2-ZrO2複合NF膜の分離特性
    貞 佑樹, YOSHIOKA TOMOHISA, 中川 敬三, 新谷 卓司, 神尾 英治, 松山 秀人
    化学工学会第50回秋季大会, May 2018, Japanese, 化学工学会, 鹿児島市, Domestic conference
    Oral presentation

  • 気体透過法による多孔性無機膜のin-situサブナノ細孔径分布評価法の開発
    小川 祐生, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    日本膜学会第40年会, May 2018, Japanese, 東京, Domestic conference
    Poster presentation

  • ニオブ酸化物ナノシート積層型分離膜の酸化グラフェン導入によるナノろ過特性の向上
    國松 美里, NAKAGAWA KEIZO, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    日本膜学会第40年会, May 2018, Japanese, 東京, Domestic conference
    Poster presentation

  • キュービック型メソポーラスシリカ膜で被覆されたPt触媒の触媒活性と構造耐久性
    NAKAGAWA Keizo, 吉田 晶, 西田 優, 加藤 雅裕, YOSHIOKA Tomohisa, MATSUYAMA Hideto, 杉山 茂
    日本膜学会第40年会, May 2018, Japanese, 日本膜学会, 東京都, Domestic conference
    Oral presentation

  • RO/FO膜における水透過の分子動力学シミュレーション
    YOSHIOKA Tomohisa, 川勝孝博
    日本膜学会第40年会, May 2018, Japanese, 日本膜学会, 東京都, Domestic conference
    Oral presentation

  • Pt内包シリカナノチューブを利用した触媒膜の作製
    岩﨑 太幹, NAKAGAWA Keizo, SHINTANI Takuji, KAMIO Eiji, MATSUYAMA Hideto, YOSHIOKA Tomohisa
    分離技術会年会2018, May 2018, Japanese, 分離技術会, 千葉県習志野市, Domestic conference
    Poster presentation

  • ⾦属酸化物ナノシート/酸化グラフェン積層膜の作製と膜性能に及ぼす複合⽐の影響
    國松 美里, NAKAGAWA KEIZO, 世良 友宏, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第20回化学工学会学生発表会, Mar. 2018, Japanese, 広島, Domestic conference
    Oral presentation

  • 有機溶媒耐性を有するポリアミド系複合薄膜の開発
    中川 湧貴, SHINTANI TAKUJI, TAKAHASHI TOMOKI, HASEGAWA Susumu, NAKAGAWA KEIZO, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 分子動力学法を用いたイオン液体水溶液の特性評価と正浸透膜透過シミュレーション
    佐田久 紗暉, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, 三野 泰志, TAKAHASHI TOMOKI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 分子動力学法による水中の高分子膜表面近傍におけるシリカナノ粒子の挙動解析
    岡田 恵丞, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 分子シミュレーションによる新規ポリイミド膜の構造設計と気体透過特性評価
    片山 基輔, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, 藤原 寛, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 分子シミュレーションによるポリアミド膜設計とFO/RO透水性能評価
    古高 啓介, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, 川勝 孝博, 藤村 侑, Wu Hao-Chen, SAEKI DAISUKE, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 剥離法により調製した金属酸化物ナノシートを利用した積層薄膜の作製と水処理膜への応用
    世良 友宏, NAKAGAWA KEIZO, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 電気透析排水中の2価陽イオンと2価陰イオンを分離する新規ナノ濾過膜の開発
    濵田 慎之介, SHINTANI TAKUJI, 赤松 憲樹, NAKAGAWA KEIZO, HASEGAWA Susumu, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 電気透析排水から2価陽イオンと2価陰イオンを選択分離する新規ナノ濾過膜の開発
    濵田 慎之介, SHINTANI TAKUJI, 赤松 憲樹, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, HASEGAWA Susumu, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    日本海水学会若手会第9回学生研究発表会, Mar. 2018, Japanese, 東京, Domestic conference
    Oral presentation

  • 中空糸膜を利用した正浸透法および逆浸透法における膜ファウリング特性の比較検討
    岡本 将尚, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, HASEGAWA Susumu, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 正浸透膜法による食品工程廃水濃縮プロセスに関する研究
    瀧上 直哉, SHINTANI TAKUJI, TAKAHASHI TOMOKI, HASEGAWA Susumu, NAKAGAWA KEIZO, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 正浸透膜の選択透過性の向上と糖液濃縮およびバイオエタノール生産に及ぼす効果
    張 一涵, Keizo Nakagawa, Kengo Sasaki, 渋谷 真史, Tomoki Takahashi, Takuji Shintani, Tomohisa Yoshioka, 長谷川 進, Michimasa Kishimoto, Eiji Kamio, Akihiko Kondo, Hideto Matsuyama
    化学工学会第83年会, Mar. 2018, Japanese, 化学工学会, 吹田市, Domestic conference
    Poster presentation

  • 正浸透膜の選択透過性の向上と糖液濃縮およびバイオエタノール生産に及ぼす効果
    張 一涵, NAKAGAWA KEIZO, SASAKI KENGO, 渋谷 真史, TAKAHASHI TOMOKI, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, HASEGAWA Susumu, KISHIMOTO MICHIMASA, KAMIO EIJI, KONDO AKIHIKO, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • 気体透過法による多孔膜のサブナノ細孔径分布評価
    小川 祐生, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第20回化学工学会学生発表会, Mar. 2018, Japanese, 広島, Domestic conference
    Oral presentation

  • ポリケトン膜のアミン修飾による耐圧性向上の要因と正浸透膜への応用
    呉 蒋霊川, NAKAGAWA KEIZO, FANG LIFENG, TAKAHASHI TOMOKI, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, HASEGAWA Susumu, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • キレート配位子を鋳型とするナノ多孔性TiO2-ZrO2複合膜の作製と性能評価
    貞 佑樹, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • TiO2-ZrO2-有機キレート配位子複合ガス分離膜の作製とCO2透過特性の評価
    平井 翔一, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • Pt内包中空シリカナノチューブ触媒の調製と脱水素反応用触媒膜への適用
    岩﨑 太幹, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第83回年会, Mar. 2018, Japanese, 大阪, Domestic conference
    Poster presentation

  • ガス分離膜開発と分子シミュレーション
    YOSHIOKA TOMOHISA
    第２回 環境セミナー, Jan. 2018, Japanese, 京都府中小企業技術センター, Domestic conference
    Public discourse

  • 2D金属酸化物ナノシート材料を利用した積層膜の作製と膜分離性能
    NAKAGAWA KEIZO, 世良 友宏, 國松 美里, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会金沢大会2017, Dec. 2017, Japanese, 石川, Domestic conference
    Oral presentation

  • 分子動力学法を用いたイオン液体水溶液のLCST型相挙動を決定する因子の解明
    佐田久 紗暉, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, 三野 泰志, TAKAHASHI TOMOKI, KAMIO EIJI, MATSUYAMA HIDETO
    第8回イオン液体討論会, Nov. 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 二次元金属酸化物ナノシート積層膜の開発–水中における構造安定性と膜分離性能–
    NAKAGAWA KEIZO, 山下洋令, 世良友宏, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    膜シンポジウム2017, Nov. 2017, English, 富山, Domestic conference
    Poster presentation

  • 浸透圧補助低圧逆浸透法を用いた高濃縮膜プロセスの検討
    東郷範弘, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KAMIO EIJI, KISHIMOTO MICHIMASA, MATSUYAMA HIDETO
    膜シンポジウム2017, Nov. 2017, English, 富山, Domestic conference
    Poster presentation

  • TiO2–ZrO2– 有機キレート複合材料を用いたCO2 分離膜の作製と特性評価
    平井翔一, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    膜シンポジウム2017, Nov. 2017, English, 富山, Domestic conference
    Poster presentation

  • TEMPERATURE-RESPONS IVE PROPERTY OF DRAW SOLUTIONS FOR FORWARD OSMOS IS DESALINATION: A MOLECULAR SIMULATION STUDY
    Saki SADAHISA, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Yasushi MINO, Eiji KAMIO, Hideto MATSUYAMA
    The 11th International Conference onSeparation Science and Technology(ICSST17), Nov. 2017, English, 韓国（釜山）, International conference
    Poster presentation

  • NON-EQUILIBRIUM MOLECULAR DYNAM ICS SIMULATION OF WATER TRANSPORT THROUGH TiO2 NANOPOROUS MEMBRANES
    Yuta SUZUKI, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Yasushi MINO, Eiji KAMIO, Hideto MATSUYAMA
    The 11th International Conference onSeparation Science and Technology(ICSST17), Nov. 2017, English, 韓国（釜山）, International conference
    Poster presentation

  • MOLECULAR SIMULATION OF CYCLIC PEPTIDE NANOTUBES FOR NOVEL WATER CHANNEL
    Tomohisa YOSHIOKA, Hao-Chen WU, Keizo NAKAGAWA, Takuji SHINTANI, Hiroki NAGASAWA, Masakoto KANEZASHI, Toshinori TSURU, Daisuke SAEKI, Hideto MATSUYAMA
    The 11th International Conference onSeparation Science and Technology(ICSST17), Nov. 2017, English, 韓国（釜山）, International conference
    Poster presentation

  • FABRICAT ION OF HIGHLY STABLE STACKED NIOBATE NANOSHEET MEMBRANES FOR NANOFILTRAT ION
    Keizo NAKAGAWA, Tomohiro SERA, Hiroharu YAMASHITA, Daisuke SAEKI, Tomohisa YOSHIOKA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 11th International Conference onSeparation Science and Technology(ICSST17), Nov. 2017, English, 韓国（釜山）, International conference
    Oral presentation

  • EFFECT OF NANOSHEET PREPARATION METHODS ON THE MEMBRANE PERFORMANCE OF STACKED NIOBATE NANOSHEET MEMBRANES
    Tomohiro SERA, Keizo NAKAGAWA, Hiroharu YAMASHITA, Misato KUNIMATSU, Daisuke SAEKI, Takuji SHINTANI, Tomohisa YOSHIOKA, Eiji KAMIO, Hideto MATSUYAMA
    The 11th International Conference onSeparation Science and Technology(ICSST17), Nov. 2017, English, 韓国（釜山）, International conference
    Poster presentation

  • CHARACTERIZATION OF NANOPOROUS TITANIA-ZIRCONIA COMPOSITE MEMBRANES PREPARED BY USING ORGANIC CHELATING LIGANDS
    Yuki SADA, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    The 11th International Conference onSeparation Science and Technology(ICSST17), Nov. 2017, English, 韓国（釜山）, International conference
    Poster presentation

  • 気体透過法による多孔膜のサブナノ細孔径分布評価
    小川 祐生, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第16 回無機膜研究会, Oct. 2017, Japanese, 静岡, Domestic conference
    Poster presentation

  • メンブレンリアクターへの利用を目指した新規シリカ被覆金属触媒の調製
    岩崎 太幹, NAKAGAWA KEIZO, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第16 回無機膜研究会, Oct. 2017, Japanese, 静岡, Domestic conference
    Poster presentation

  • 2D ナノシート材料を利用した積層型無機膜の作製と膜性能評価
    國松 美里, NAKAGAWA KEIZO, 世良 友宏, 山下 洋令, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第16 回無機膜研究会, Oct. 2017, Japanese, 静岡, Domestic conference
    Poster presentation

  • 有機溶媒耐性を有する高分子系複合薄膜の開発
    中川 湧貴, SHINTANI TAKUJI, TAKAHASHI TOMOKI, SAEKI DAISUKE, NAKAGAWA KEIZO, MATSUYAMA HIDETO, YOSHIOKA TOMOHISA
    化学工学会第49回秋季大会, Sep. 2017, Japanese, 名古屋, Domestic conference
    Oral presentation

  • 正浸透膜法による糖液濃縮およびバイオエタノール生産に及ぼすポリアミド層の分離性能の影響
    張 一涵, Keizo Nakagawa, Kengo Sasaki, 渋谷 真史, Tomoki Takahashi, Takuji Shintani, Tomohisa Yoshioka, Michimasa Kishimoto, Eiji Kamio, Akihiko Kondo, Hideto Matsuyama
    化学工学会第49回秋季大会, Sep. 2017, Japanese, 化学工学会, 名古屋市, Domestic conference
    Poster presentation

  • ニオブ酸ナノシート積層型分離膜のシートサイズが及ぼす膜性能への影響
    世良 友宏, NAKAGAWA KEIZO, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    化学工学会第49回秋季大会, Sep. 2017, Japanese, 名古屋, Domestic conference
    Poster presentation

  • Preparation of Amphotericin B-Ergosterol structures and molecular simulation of water adsorption and diffusion
    Hao-Chen Wu, Tomohisa YOSHIOKA, Keizo NAKAGAWA, Takuji SHINTANI, Toshinori TSURU, Daisuke SAEKI, Abdul Rajjak, Hideto MATSUYAMA
    2017 International Congress on Membranes and Membrane Processes (ICOM2017), Jul. 2017, English, USA(San Francisco), International conference
    Poster presentation

  • Preparation and nanofiltration performance of niobate nanosheet membranes
    Keizo NAKAGAWA, Hiroharu YAMASHITA, Daisuke SAEKI, Tomohisa Yoshioka, Takuji Shintani, Eiji Kamio, Hideto MATSUYAMA
    2017 International Congress on Membranes and Membrane Processes (ICOM2017), Jul. 2017, English, USA(San Francisco), International conference
    Oral presentation

  • Effects of separation performance of forward osmosis membranes on sugar concentration for bio-ethanol production
    Yihan ZHANG, Keizo NAKAGAWA, Masafumi SHIBUYA, Kengo SASAKI, Tomoki TAKAHASHI, Takuji SHINTANI, Tomohisa YOSHIOKA, Michimasa KISHIMOTO, Eiji KAMIO, Akihiko KONDO, Hideto MATSUYAMA
    2017 International Congress on Membranes and Membrane Processes (ICOM2017), Jul. 2017, English, USA(San Francisco), International conference
    Poster presentation

  • Effect of gas molecular properties on characterization of microporous membrane structures based on the modified GT model: molecular dynamics study
    Yoshioka Tomohisa, Tamaoki Kazuya, Nagasawa Hiroki, Kanezashi Masakoto, Tsuru Toshinori
    11th International Congress onMembranes and Membrane Processes(ICOM2017), Jul. 2017, English, International conference
    Poster presentation

  • Direct numerical simulation of cake formation in cross-flow microfiltration process
    Junta Nishitani, Yasushi Mino, Tomohisa Yoshioka, Hideto Matsuyama
    2017 International Congress on Membranes and Membrane Processes (ICOM2017), Jul. 2017, English, USA(San Francisco), International conference
    Poster presentation

  • Characterization of porous titania-zirconia composite membrane materials prepared by using organic chelating ligands
    Tomohisa YOSHIOKA, Yuki SADA, Keizo NAKAGAWA, Takuji SHINTANI, Eiji KAMIO, Hideto MATSUYAMA
    2017 International Congress on Membranes and Membrane Processes (ICOM2017), Jul. 2017, English, USA(San Francisco), International conference
    Poster presentation

  • 有機溶媒耐性を有するポリアミド活性層複合膜の開発
    中川 湧貴, SHINTANI TAKUJI, NAKAGAWA KEIZO, YOSHIOKA TOMOHISA, TAKAHASHI TOMOKI, KAMIO EIJI, MATSUYAMA HIDETO
    日本膜学会第39年会, May 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 有機キレートをテンプレートとする多孔性TiO2-ZrO2複合膜の特性評価
    貞 佑樹, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    日本膜学会第39年会, May 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • Membrane separation technology for CO2 separation and recovery in Japan
    YOSHIOKA TOMOHISA, KAMIO EIJI
    日本膜学会第39年会, May 2017, Japanese, The Membrane Society of Japan, Domestic conference
    [Invited]
    Invited oral presentation

  • 正浸透膜の耐圧性能に及ぼす多孔性支持膜へのアミン修飾の影響
    呉 蒋霊川, NAKAGAWA KEIZO, TAKAHASHI TOMOKI, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KAMIO EIJI, MATSUYAMA HIDETO
    日本膜学会第39年会, May 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 金属酸化物ナノシート積層膜の形成と膜性能に及ぼす各種ナノシート合成法の影響
    世良 友宏, NAKAGAWA KEIZO, 山下 洋令, SAEKI DAISUKE, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KAMIO EIJI, MATSUYAMA HIDETO
    日本膜学会第39年会, May 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • TiO2ナノ細孔内水透過シミュレーションと透過モデルによる解析
    鈴木 悠太, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, 三野 泰志, KAMIO EIJI, MATSUYAMA HIDETO
    分離技術会年会2017, May 2017, Japanese, 神奈川, Domestic conference
    Oral presentation

  • TiO2-ZrO2複合膜材料のナノ細孔構造に及ぼす有機キレート配位子の影響
    貞 佑樹, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    分離技術会年会2017, May 2017, Japanese, 神奈川, Domestic conference
    Oral presentation

  • Characterization of Cyclic Peptide Nanotube Structures and Water Permeability Estimation: a Molecular Simulation Study
    Hao-Chen Wu, Tomohisa Yoshioka, Hiroki Nagasawa, Masakoto Kanezashi, Toshinori Tsuru, Daisuke Saeki, Hideto Matsuyama
    The 5th Asian Graduate Student Symposium on Membrane Engineering (AGSM5), Apr. 2017, English, JAPAN（KOBE), Domestic conference
    Oral presentation

  • 有機キレートを用いた多孔性TiO2-ZrO2複合膜の作製と構造評価
    SADA YUKI, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA HIDETO
    第19回化学工学会学生発表会 (豊中大会), Mar. 2017, Japanese, 大阪, Domestic conference
    Oral presentation

  • 分子動力学法を用いたTiO2ナノ細孔内水透過機構の検討
    SUZUKI YUTA, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, MINO YASUSHI, KAMIO EIJI, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 分子シミュレーションによる温度応答性イオン液体水溶液の相転移挙動解析
    SADAHISA SAKI, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, MINO YASUSHI, TAKAHASHI TOMOKI, KAMIO EIJI, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 二次元チャネル構造を有する金属酸化物ナノシート積層膜の膜性能評価
    NAKAGAWA KEIZO, 山下 洋令, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, 加藤 雅裕, 杉山 茂, Eiji KAMIO, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, English, 東京, Domestic conference
    Oral presentation

  • 直接数値シミュレーションを用いた粒子分散液の細孔透過挙動解析
    酒井 将平, MINO Yasushi, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 多段式低圧逆浸透法を利用した塩水濃縮プロセスの検討
    東郷 範弘, 田中 裕大, NAKAGAWA KEIZO, TAKAHASHI Tomoki, Eiji KAMIO, SHINTANI TAKUJI, KISHIMOTO MICHIMASA, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    第19回化学工学会学生発表会（豊中大会）, Mar. 2017, Japanese, 大阪, Domestic conference
    Oral presentation

  • 数値シミュレーションを用いたコアレッサー型油水分離膜の設計
    長谷川 礼乃, MINO Yasushi, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 浸透圧補助低圧逆浸透法による海水高濃縮技術に関する基礎的検討
    東郷 範弘, 田中 裕大, NAKAGAWA KEIZO, TAKAHASHI Tomoki, Eiji KAMIO, SHINTANI TAKUJI, KISHIMOTO MICHIMASA, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    日本海水学会若手会 第８回学生研究発表会, Mar. 2017, Japanese, 山口, Domestic conference
    Oral presentation

  • 吸引ろ過法により作製されたニオブ酸ナノシート積層膜の膜性能に及 ぼす作製条件の影響
    山下 洋令, NAKAGAWA KEIZO, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, 加藤 雅裕, 杉山 茂, Eiji KAMIO, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, English, 東京, Domestic conference
    Poster presentation

  • ポリアミド活性層の表面改質が及ぼす正浸透膜法による糖液濃縮およ びバイオエタノール生産への影響
    張 一涵, NAKAGAWA KEIZO, 渋谷 真史, TAKAHASHI Tomoki, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KISHIMOTO MICHIMASA, Eiji KAMIO, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • TiO2-ZrO2-有機キレート複合材料の特性評価とCO2分離膜への応用
    HIRAI SHOICHI, YOSHIOKA TOMOHISA, NAKAGAWA KEIZO, SHINTANI TAKUJI, KAMIO EIJI, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2017, Japanese, 東京, Domestic conference
    Poster presentation

  • 糖液濃縮用分離膜の表面改質による糖類と発酵阻害物質の選択透過性への影響
    張 一涵, NAKAGAWA KEIZO, 渋谷 真史, TAKAHASHI Tomoki, Eiji KAMIO, SHINTANI TAKUJI, KISHIMOTO MICHIMASA, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    膜シンポジウム2016, Dec. 2016, Japanese, 大阪, Domestic conference
    Poster presentation

  • 吸引ろ過法を用いた異なる膜厚さのナノシート積層膜の作製と膜分離性能
    山下 洋令, NAKAGAWA KEIZO, SAEKI DAISUKE, Eiji KAMIO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, MATSUYAMA Hideto, 加藤 雅裕, 杉山 茂
    膜シンポジウム2016, Dec. 2016, Japanese, 大阪, Domestic conference
    Poster presentation

  • クロスフローろ過におけるケーク形成過程に及ぼす膜面形状の影響
    西谷 詢太, MINO Yasushi, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    膜シンポジウム2016, Dec. 2016, Japanese, 大阪, Domestic conference
    Poster presentation

  • Membrane Technology for CO2 Separation in Kobe University-Ionic Liquid Impregnated Gel and Ceramic Membranes-
    Yoshioka Tomohisa, Kamio Eiji, Matsuyama Hideto
    Kobe University Academic Research and Education Forum（KUAREF）, Dec. 2016, English, The Margo Hotel, Depok, Indonesia, International conference
    Nominated symposium

  • 吸引ろ過法により作製されたニオブ酸ナノシート積層膜の膜性能評価
    山下 洋令, NAKAGAWA KEIZO, SAEKI DAISUKE, Eiji KAMIO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, MATSUYAMA Hideto, 加藤 雅裕, 杉山 茂
    第15回無機膜研究会, Nov. 2016, Japanese, 愛知, Domestic conference
    Poster presentation

  • CO2 permeation and CO2/N2 separation characteristics of sol-gel derived microporous amino-silica membranes
    Yoshioka Tomohisa, Nagao Yukiharu, Nagasawa Hiroki, Kanezashi Masakoto, Tsuru Toshinori
    THE 5TH ASIAN CONFERENCE ON INNOVATIVE ENERGY & ENVIRONMENTAL CHEMICAL ENGINEERING (ASCON-IEEChE 2016), Nov. 2016, English, The Hotel New Grand, Yokohama, Japan, International conference
    Oral presentation

  • 粒子分散液の細孔透過に伴うファウリング挙動
    酒井 将平, MINO Yasushi, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    化学工学会第48回秋季大会, Sep. 2016, Japanese, 徳島, Domestic conference
    Oral presentation

  • 吸引ろ過法による二次元ナノシート積層膜の作製と膜分離特性
    山下 洋令, SAEKI DAISUKE, NAKAGAWA KEIZO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, 加藤 雅裕, 杉山 茂, MATSUYAMA Hideto
    化学工学会第48回秋季大会, Sep. 2016, Japanese, 徳島, Domestic conference
    Oral presentation

  • 吸引ろ過法による二次元ナノシート積層膜の作製と膜分離性能
    山下 洋令, SAEKI DAISUKE, NAKAGAWA KEIZO, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, 加藤 雅裕, 杉山 茂, MATSUYAMA Hideto
    化学工学会第48回秋季大会, Sep. 2016, Japanese, 徳島, Domestic conference
    Oral presentation

  • O/Wエマルションの膜細孔透過におけるぬれ性の影響
    長谷川 礼乃, MINO Yasushi, 新戸 浩幸, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    化学工学会第48回秋季大会, Sep. 2016, Japanese, 徳島, Domestic conference
    Poster presentation

  • Preparation and gas permeation characteristics of microporous carbon-ceramic membranes by counter diffusion thermal CVD of organic solvent vapor
    Yoshioka Tomohisa, Kagawa Takahiko, Nagasawa Hiroki, Kanezashi Masakoto, Tsuru Toshinori
    The 10th Conference of Aseanian Membrane Society (AMS10), Jul. 2016, English, Nara Kasugano International Forum IRAKA, Nara, Japan, International conference
    Poster presentation

  • Preparation and Gas Permeation Characteristics of Microporous Amorphous TiO2-ZrO2-Organic Chelate Membranes
    YOSHIOKA TOMOHISA, Ushio Yuuki, Nagasawa Hiroki, Kanezashi Masakoto, Tsuru Toshinori
    Nara Kasugano International Forum IRAKA, Nara, Japan, Jul. 2016, English, International conference
    Keynote oral presentation

  • Molecular simulation study of vapour and liquid phase permeation of water through organosilica membranes
    Yoshioka Tomohisa, Narukiyo Shintaro, Nagasawa Hiroki, Kanezashi Masakoto, Tsuru Toshinori
    15th International Conference on Inorganic Membranes (ICIM-14)15th International Conference on Inorganic Membranes, Jun. 2016, English, Global Learning Center, Georgia Institute of Technology, Atlanta, GA, USA, International conference
    Poster presentation

  • 二次元チャネル構造を有する金属酸化物ナノシート積層膜の膜性能評価
    NAKAGAWA KEIZO, 山下 洋令, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, 加藤 雅裕, 杉山 茂, Eiji KAMIO, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2016, English, 東京, Domestic conference
    Oral presentation

  • 直接数値シミュレーションを用いた粒子分散液の細孔透過挙動解析
    酒井 将平, MINO Yasushi, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2016, Japanese, 東京, Domestic conference
    Poster presentation

  • 多段式低圧逆浸透法を利用した塩水濃縮プロセスの検討
    東郷 範弘, 田中 裕大, NAKAGAWA KEIZO, TAKAHASHI Tomoki, Eiji KAMIO, SHINTANI TAKUJI, KISHIMOTO MICHIMASA, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    第19回化学工学会学生発表会（豊中大会）, Mar. 2016, Japanese, 大阪, Domestic conference
    Oral presentation

  • 数値シミュレーションを用いたコアレッサー型油水分離膜の設計
    長谷川 礼乃, MINO Yasushi, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2016, Japanese, 東京, Domestic conference
    Poster presentation

  • 浸透圧補助低圧逆浸透法による海水高濃縮技術に関する基礎的検討
    東郷 範弘, 田中 裕大, NAKAGAWA KEIZO, TAKAHASHI Tomoki, Eiji KAMIO, SHINTANI TAKUJI, KISHIMOTO MICHIMASA, YOSHIOKA TOMOHISA, MATSUYAMA Hideto
    日本海水学会若手会 第８回学生研究発表会, Mar. 2016, Japanese, 山口, Domestic conference
    Oral presentation

  • 吸引ろ過法により作製されたニオブ酸ナノシート積層膜の膜性能に及 ぼす作製条件の影響
    山下 洋令, NAKAGAWA KEIZO, SAEKI DAISUKE, YOSHIOKA TOMOHISA, SHINTANI TAKUJI, 加藤 雅裕, 杉山 茂, Eiji KAMIO, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2016, English, 東京, Domestic conference
    Poster presentation

  • ポリアミド活性層の表面改質が及ぼす正浸透膜法による糖液濃縮およ びバイオエタノール生産への影響
    張 一涵, NAKAGAWA KEIZO, 渋谷 真史, TAKAHASHI Tomoki, SHINTANI TAKUJI, YOSHIOKA TOMOHISA, KISHIMOTO MICHIMASA, Eiji KAMIO, MATSUYAMA Hideto
    化学工学会第82年会, Mar. 2016, English, 東京, Domestic conference
    Poster presentation

  • Characterization of subnano-scale porous structures and gas permeation properties of microporous ceramic membranes
    YOSHIOKA TOMOHISA
    40th International Conference and Exposition on Advanced Ceramics and Composites, Jan. 2016, English, Hilton Daytona Beach Resort and Ocean Center, Florida, USA, International conference
    Keynote oral presentation

■ Research Themes
  • Mechanism elucidation and control of efficient release of healing agent in self-healing coatings containing nanofibers
    矢吹 彰広, 吉岡 朋久, 李 志河
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Hiroshima University, 01 Apr. 2020 - 31 Mar. 2023

  • Depelopment of microporous TiO2-ZrO2-organic composite membranes with ultra-high permeability for organic solvent liquid phase separation
    吉岡 朋久, 中川 敬三, 新谷 卓司
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Kobe University, 01 Apr. 2020 - 31 Mar. 2023

  • Development of ultrathin separation membranes utilizing 2D nanosheet materials for water treatment
    中川 敬三, 松山 秀人, 吉岡 朋久
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2019 - 31 Mar. 2022

  • 松山 秀人, 松方 正彦, 小野 努, 吉岡 朋久, 中川 敬三, 神尾 英治, 佐伯 大輔, 高橋 智輝, 稲田 飛鳥, 彌田 智一
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), Kobe University, 01 Apr. 2018 - 31 Mar. 2022
    １．新規水チャネル型FO膜の創製 1-1．環状ペプチド分子集合体チャネル膜の創製（松山、吉岡、佐伯）では、分子動力学計算を用いて環状ペプチドチャネル分子を設計、合成し、これをリン脂質二分子膜に導入することで新規生体模倣型FOチャネル膜の開発を行った。1-2．高分子液晶垂直配向チャネル膜の創製（彌田、佐伯、稲田）では、高分子液晶の垂直配向シリンダー構造を水チャネルとして利用したFO膜の創製を行った。各種支持膜との複合化製膜プロセスを構築した。1-3．革新的ロバスト無機ゼオライトFO膜の創製（松方）では、ZSM-5等のゼオライトが持つ親水性ミクロ細孔特性を利用して、安定性が高く高温にも耐える全く新しい無機FO膜の開発を行った。1-4．計算機科学による高機能FO膜開発支援 (吉岡)では、分子動力学計算により水チャネルの正浸透透水モデルを構築し、高透水性発現に必要な構造や物性をシミュレーションにより解明するとともに、結果のフィードバックにより、高透水性FO膜開発支援を行った。 ２．新規刺激応答性駆動溶液（DS）の創製（小野、高橋） 熱応答性イオン液体DSの創製を目指し100種類以上のイオン液体分子について量子化学計算を活用して系統的なスクリーニングを行い、化学構造と温度相転移特性との関係性を明らかにするとともに、熱応答性イオン液体の温度依存的浸透圧発現機構を解析し、高浸透圧と相分離特性を両立する高性能なイオン液体DSの創出を行った。 ３．FO膜透過とDS再生を含む連続システムによるFS評価とFO膜システムの実証（松山、神尾、中川） FO膜とDSを用いた連続FOシステムの構築を行い、構築したシステムにより、熱応答性イオン液体DSの性能確認を行うとともに、海水淡水化を想定したFO膜プロセスで連続的にモデル海水から純水を得ることに成功した。
    Competitive research funding

  • Development of highly functional stacked nanosheet membranes with antifouling property
    Nakagawa Keizo
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Kobe University, 01 Apr. 2016 - 31 Mar. 2019
    Porous inorganic membranes have advantages of high temperature resistance, chemical stability and mechanical strength, therefore, various researches for water treatment have been investigated. In this study, stacked nanosheet membranes utilizing two-dimensional nanosheets were fabricated for the development of functional inorganic membranes with superior water permeability, separation performance as well as high antifouling property. We have successfully fabricated the stacked nanosheet membranes with high structural stability using simple vacuum filtration method. The nanosheet membranes show high rejection against anionic organic dyes and divalent salts, which were found to act as nanofiltration. Furthermore, the fouling resistance with recovery function of water flux under ultraviolet light irradiation was also confirmed.

  • Development of technologies simulating the transport of micropollutants through reverse osmosis membrane for potable water reuse
    FUJIOKA Takahiro, YOSHIOKA Tomohisa
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A), Grant-in-Aid for Young Scientists (A), Nagasaki University, 01 Apr. 2016 - 31 Mar. 2018
    This project evaluated the importance of membrane properties of reverse osmosis (RO) membranes on the transport of micropollutants, and identified that there could be RO skin layer properties other than skin layer thickness and free-volume hole-radius that govern water and solute permeation. In addition, this project applied a steric pore-flow model to predict the rejection of micropollutants, and found that their rejection can be predicted by estimating the free-volume hole-size with a single reference solute and membrane pure water permeability. This project also employed molecular dynamics (MD) simulation techniques to predict the transport behaviors of water and three N-nitrosamines. MD simulations showed that diffusivity of N-nitrosamines increased inversely with respect to their molecular size.

  • Matsuyama Hideto, MIYATA Takashi, KUMANO Atsuo
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), Kobe University, 01 Apr. 2015 - 31 Mar. 2018
    In this study, innovative forward osmosis (FO) membranes and draw solutions (DSs) were developed for the purpose of construction of water treatment process with infinitely close to zero energy consumption. The water channel membrane with biomimetic property having high water permeability and high salt rejection, hydrogel membrane with micro-phase separation and electrostatic repulsion property, and robust inorganic membrane with high organic solvent resistance and high mechanical strength were successfully developed as FO membranes. In addition, photo-responsive DS and both carbon dioxide responsive and thermo-responsive DS were developed as novel regenerable DSs.
    Competitive research funding

  • Yoshioka Tomohisa
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), 01 Apr. 2015 - 31 Mar. 2018, Principal investigator
    Organic chelating ligands could be remained in a ceramic membrane when it was calcined at 350 dgree C in nitrogen atmosphere. TiO2-ZrO2-Dopaine sol coated membranes on alumina support showed a CO2/N2 permeation ratio of 20 at 35 degree C, which indicated that TiO2-ZrO2-based gas separation membranes could be prepared. On the other hand, TiO2-ZrO2 membranes, prepared by removing organic chelate ligand as a template for forming porous structures, had fractionation performance of molecular weight cut-off around 2,000. This type of membrane is promising for a nanofiltration membrane. From the results of non-equilibrium molecular dynamics permeation simulations under a pressure gradient condition, molecular permeation flux would depend on interaction of permeating molecules with pore surface.
    Competitive research funding

  • Photo-induced sol-gel processing for low-temperature fabrication of high-performance silsesquioxane membranes for use in molecular separation
    Tsuru Toshinori, YOSHIOKA TOMOHISA, KANEZASHI MASAKOTO
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Challenging Exploratory Research, Grant-in-Aid for Challenging Exploratory Research, Hiroshima University, 01 Apr. 2013 - 31 Mar. 2016
    Silsesquioxane (SQ) has demonstrated properties that are seen in both silica (SiO2, inorganic) and silicone (organic). Conventionally, SQ-derived sols are coated onto ceramic supports, followed by firing at 200~400C, which facilitates further condensation to form a SQ separation layer with high separation performance. In this work, we proposed, for the first time, the strategy for fabricating silsesquioxane (SQ) membranes at low temperature using photo-induced sol-gel processing. Radical and cationic polymerization of SQ membranes showed high degrees of separation factor and permeance for water/isopropanol separation in pervaporation.

  • Development of extremely thin Molecular-Net-Sieving membranes
    TSURU Toshinori, GUNGI Takahiro, ITO Kenji, YOSHIOKA Tomohisa, KANEZASHI Masakoto
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), Hiroshima University, 01 Apr. 2012 - 31 Mar. 2015
    A novel concept of Molecular-Net-Sieving (MNS) where space consisting of networks can separate molecules based on the molecular sieving mechanism is proposed for the development of extremely high H2 permeable membranes. New silicon-based alkoxides and oligomers were prepared, and positron annihilation spectroscopy was applied to evaluate the pore structures. In addition, Molecular-Net-Sieving membranes were prepared from various types of precursors and characterized. Molecular-Net-Sieving membranes were confirmed to show higher hydrogen permeance higher than 1x10-6 mol m-2 Pa-1 s-1, and high separation factors for H2/propane (>1,000) and H2/SF6 (>10,000).

  • Development of microporous carbon-ceramic membranes by reactive thermal CVD of organic gases
    YOSHIOKA TOMOHISA, KANEZASHI Masakoto
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Hiroshima University, 01 Apr. 2012 - 31 Mar. 2015
    Three types of organic precursors of propylene (C3H6), isobutylene (iso-C4H8), and toluene were employed and counter diffusion CVD technique was used to prepare carbon-SiO2 membranes. Organic gas diluted by nitrogen were fed from outside of the cylinder shaped Al2O3 substrate and also nitrogen diluted oxygen gas was fed from inside the substrate to meet a carbon precorsor preferably in pores of SiO2-ZrO2 intermediate layer on the substrate. After counter diffusion CVD operation at 400 C using C3H6 as a precursor, helium permeance at 200 C was 3.9 x 10-7 mol m-2 s-1 Pa-1 with He/N2 and He/SF6 selectivity of 27 and 215, respectively. For the case of iso-C4H8 and toluene as precursors, helium permeance of 2.8 x 10-7 and 1.0 x 10-7 mol m-2 s-1 Pa-1 with improved He/N2 and He/SF6 selectivity of 74, 343 for iso-C4H8, and 121, and 1620 for toluene, respectively, were obtained, possibly due to the large molecular size of precursor.

  • Silica network engineering for advanced separation membranes
    TOSHINORI Tsuru, YOSHIOKA Tomohisa, KANEZASHI Maskoto, OHSHITA Joji
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Hiroshima University, 2009 - 2011
    Structured alkoxides consisting of organic functional groups as pendant groups or main chain have been proposed for the control of amorphous silica networks. We proposed Normalized Knudsen-based Permeance(NKP) to evaluate pore sizes less than 1 nm. Bis(triethoxysilyｌ) ethane(BTESE)-derived silica membranes were found to show high permeability and selectivity to gas separation(H2/ organic gases), dehydration of organic solutions, and reverse osmosis

  • Development of characterization method for sub-nano scale small voids of amorphous materials by multi probe gas diffusion technique.
    YOSHIOKA Tomohisa, KANEZASHI Masakoto
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Hiroshima University, 2009 - 2011
    A novel equipment and technique for characterization of small void volume of microporous powder sample were developed based on the volumetric method by using various gas molecules as a probe molecule. As microporous materials, the porous powder sample of amorphous silica and BTESE(bis-triethoxysilyl ethane) silica was prepared, and the detailed void structure was evaluated using the multi-probe gas molecular diffusion method. This technique enables us to estimate the difference in the sub-nano scale void structure of these amorphous materials. The validity of this technique verified by evaluating the void volume of Y type zeolite whose micro structure is well known, and the theoretical pore volume was successfully obtained. The difference in the structure of amorphous silica and BTESE silica was examined also by the molecular simulation. The simulated molecular size dependence of gas diffusivity in these small void structures showed good correlation with the void volume distribution measured with the multi-probe gas molecular diffusion method.

  • 構造を制御した多孔性膜におけるナノ制限空間ダイナミクスと高度分離システムへの応用
    都留 稔了, 吉岡 朋久
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Hiroshima University, 2007 - 2008
    本研究では,ナノ〜サブナノ細孔における液相系の透過機構の解明と高度分離システムへの応用を目的とし,以下を具体的な研究実績とする。 (1)細孔構造および表面特性を制御したナノ多孔性膜の作製 これまでに製膜実績のあるSiO_2,TiO_2を用いて,ゾルーゲル法により平均細孔径0.5nm〜5nmを有する多孔膜の作製を行った。有機無機ハイブリッド膜は,セラミック多孔膜をまず作製した後にシランカップリング剤を用いて細孔内表面の疎水化を行うpost-modification法と,疎水基を有するアルコキシドを用い疎水ゾルを調製するin-situ法によった。特に,今年度はTEOSとMTESを用いる疎水ゾル(Me-SiO2)ゾルの調製条件を詳細に検討し,濃度およびTEOS/MTES比により,1nmまでの疎水性細孔制御に成功した。 (2)ナノ多孔性膜および膜材料の特性評価 膜細孔径のナノ細孔評価として,ナノパームポロメトリー法を用い0.5〜50nmの細孔径を測定した。コーティング膜の各種溶媒の接触角を測定することで,Me-SO2の臨界表面自由エネルギーは35-20J/m^2であり,ヘキサンでは完全濡れが期待できること,従って水とヘキサンでのナノパームポロメトリー測定を行なうことで,ナノ細孔の親疎水性を定量的に評価できることを明らかとした。 (3)透過性評価と分離システムへの応用:ナノ制限空間のダイナミクス ヘキサン溶媒中の微量水分の影響について検討した結果,水分濃度にかかわらずMeSiO2膜は安定した透過流束を示した。また,平均細孔径1.7nmのMe-SiO2膜のアルカン溶質の阻止特性を評価した結果,極めて滝透過性を示すと共に,分画分子量1000程度であることを明らかとした。

  • Control of metal doped amorphous frame structures and development of effective void space for gas separation membranes, using molecular dynamics simulations
    YOSHIOKA Tomohisa, TSURU Toshinori
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Hiroshima University, 2007 - 2008
    多孔性セラミック気体分離膜材料として, 金属添加シリカおよびジルコニアコロイドゾルを調製し, ゲル粉体試料の構造を評価した. これらのセラミック材料を用いることにより, 高透過選択性と安定性を有する多孔性セラミック水素分離膜の作製が可能であった. また, 様々な構造を有するアモルファスシリカ膜における気体透過現象を分子動力学シミュレーションにより再現し, 気体透過特性とアモルファス多孔性セラミック膜構造の関係を明らかとした.

  • 中温度域での完全水素分離を可能とする新規なセラミック膜の創製
    都留 稔了, 吉岡 朋久
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Exploratory Research, Grant-in-Aid for Exploratory Research, Hiroshima University, 2006 - 2007
    本研究では,シリカあるいはチタニアなどのセラミックスを膜材料として用い,選択的溶解機構に基づく新規な水素分離膜を提案している。まず,シリカ,チタニアおよびリンとの複合酸化物材料を用い,プロトン伝導性薄膜の創製を行ない,このプロトン伝導性に電子伝導性を付与すると,水素分離膜を創製することが可能となると考えられる。本研究では,この新たな水素透過機構に基づく,100-300℃での中温度域で完全水素選択性を示すセラミック膜を創製するために,以下の2種類のゾルゲル法でプロトン伝導膜の創製を行なった。 ・メソポーラスTiO_2/Tipペレット膜の開発 チタンアルコキシドをH_3PO_4触媒を用いて,メソポーラスTiO_2を作製した.従来法TiO_2と比較して比表面積が2〜4倍増加し,TiO_2(H_3PO_4)のP/Ti=0.5では最も高い比表面積262m^2/gを示した。このメソポーラスチタニアに,チタンリンゾル(TiP)をコーティングすることで,電気伝導率は200℃,水蒸気3kPa下においても高い電気伝導率14mS/cmを示すことを見出した。 ・TiO_2-P_2O_5薄膜の開発 ゾル調製時にP源としてP_2O_5(五酸化二リン)とTBOT(テトラブチルオルトチタネート)を用い,新規チタン-リン膜の作製を行い,薄膜としてプロトン伝導特性や特性評価を行った。この手法では,1stepで香典同物質の創製の可能性がある。TiO_2-P_2O_5薄膜は湿度増加と共に伝導率が一次関数的に増加し,TiO_2(P_2O_5)[P/Ti=2]は,100℃,80%RH下において最も高い伝導率180mS/cmを示した.さらにTiO_2(P_2O_5)[P/Ti=9]は,160℃,100%RH下で3S/cmとNafion膜と比較して約30倍の性能を示すことを明らかにした。

  • 多孔性無機材料による気体分離膜設計のための分子動力学膜シミュレータの開発
    吉岡 朋久
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), Hiroshima University, 2005 - 2006
    本年度は,アモルファスシリカ膜における気体透過現象を分子動力学シミュレーションにより再現することを目的として,気体透過特性におよぼす膜構成原子の動特性と膜細孔径分布の影響に着目して,以下のとおり研究を実施した. 1.シリカポリマーネットワーク膜モデルの妥当性評価とポテンシャルパラメータの最適化 分子の膜透過という動特性が分子シミュレーションで再現できているかが重要であり,これは,膜を構成する分子のポテンシャル関数およびポテンシャルパラメータをどのように設定するかに大きく左右される.アモルファスシリカ構造を規定する3体ポテンシャルパラメータの値を変化させて動径分布関数およびシリカ膜を構成する酸素原子の平均二乗変位を計算した結果,原子の平衡位置,すなわちアモルファス構造を維持したままでシリカネットワークの動きを制御することが可能であることがわかった.また気体透過速度の温度依存性より得られる活性化エネルギーは膜構成原子の動きを抑制した場合に大きくなった. 2.多元的細孔膜モデルの構築と膜透過シミュレータとしての妥当性評価 シリカネットワーク相の細孔径分布は原子密度に依存し,密度の増加にともなって平均細孔径は減少したが,密度1.8g/ml以上においては粒界的な細孔は消失し,He透過速度の温度依存性はその密度を境としてKnudsen的な透過から活性化的な傾向へと変化した.1.8g/mlの膜モデルでは実在CO_2分離膜における透過速度と近い結果が得られたが,H_2分離膜に比べて活性化エネルギーは小さかったことから,H_2分離膜のシリカネットワーク相はより高密度であると考えられる.粒子間細孔モデルを用いたCO_2透過シミュレーション結果と密度1.8g/ml膜モデルにおけるHe透過速度の結果を組み合わせて実在CO_2分離膜における気体透過速度データにフィッティングしたところ,およそ18nm四方に1個の割合で粒子間細孔が存在することが示唆され,これは,実在シリカ膜作製時に使用したコロイド粒子サイズを考慮すると妥当な結果であった.

  • Preparation of nano-structured proton conductive ceramic membranes and membrane electrode assembly (MEA) system
    TSURU Toshinori, ASAEDA Masashi, YOSHIOKA Tomohisa
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), HIROSHIMA UNIVERSITY, 2004 - 2005
    Titanium phosphorus oxide (TiP) and composites with titania (Ti/TiP) were prepared by a sol-gel method. Tip membranes coated on slide glasses showed high electrical conductivities based on surface resistivity measurements at 150℃. The conductivities increased drastically with the partial pressure of water in the range of 0 to 10 kPa, and showed an electrical conductivity as high as 10^<-2> S/cm at a vapor pressure of 2.5 kPa (relative humidity of 0.5 RH%). Two types of membrane-electrode assemblies (MEAs) : a pore-filling-type and a thin-film-type, were constructed using Anodisc【○!R】, a porous alumina membrane (pore size : 100 nm ; thickness 60 μm). The proton transport number through the pore-filling type MEA was found to be approximately one. The two types of MEAs were successfully used in fuel cell experiments in a hydrogen/ air system. The performance of the thin-film-type MEA was superior to the pore-filling-type MEA. Moreover, two types of thin-film type of MEAs were prepared using electrically-conductive porous carbon substrates. MEA-2, which were prepared after fabricating an intermediate layer consisting of mixtures of carbon particles and polyimide, showed a better i-v performance than MEA-1, which were prepared directly on porous carbon substrate.

  • 多孔性ガス分離膜における分子充填透過機構の解明とサブナノ膜細孔径分布評価への応用
    吉岡 朋久
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B), Grant-in-Aid for Young Scientists (B), Hiroshima University, 2003 - 2004
    1.凝縮性ガス透過シミュレーションによるマイクロ孔充填・透過機構の検討 非平衡分子動力学法を用いて凝縮性ガス(エタン)の透過シミュレーションを行ったところ,マイクロ孔充填相の形成による透過速度の低下が見られ,その際の圧力は細孔径が大きい方が高くなった.また,透過分子の蒸発エネルギーと吸着エネルギーを用いてマイクロ孔充填相の移動モデルを構築し,細孔径分布を考慮して数値シミュレーションを行ったところ,透過分子と膜細孔表面との相互作用および細孔径分布に由来する透過速度の減少傾向が良好に再現され,分子充填相透過現象を利用したサブナノ細孔径分布評価の理論的妥当性が示された. 2.凝縮性ガスの膜材料表面との相互作用エネルギーの評価 膜材料のシリカコロイドゾルを乾燥させ,1000℃で焼成して作成した非多孔性粉体試料における標準凝縮性ガス(エタン,プロパン,ブタン)の吸着等温線を測定し,Frenkel吸着理論を用いて各ガスとシリカ材料との相互作用パラメータを求めた.シリンダー状の細孔形状を仮定することにより,非多孔性固体表面との相互作用パラメータを基準として,細孔内ポテンシャル場の細孔径依存性を得る手法を確立した. 3.膜細孔径分布評価法の妥当性の検討 平均細孔径が異なる3種類の実在多孔性シリカ膜において,標準凝縮性ガスの透過速度の圧力依存性を測定した.標準凝縮性ガスの細孔内ポテンシャルと細孔径の関係および吸着ポテンシャル理論を用いて,透過速度の圧力依存性を透過速度と細孔径の関係に換算することにより,ガス透過に有効な細孔径分布を推算可能であった.どの凝縮性ガスを標準ガスとして用いてもそれぞれの膜について同様な細孔径分布が得られ,また,透過速度の分子サイズ依存性から予測された細孔径との定量的な一致も見られ,マイクロ孔充填相透過モデルを利用したサブナノ膜細孔径分布評価法の妥当性が示唆された.

  • 新規な透過原理に基づく完全水素選択性セラミック膜の創製
    都留 稔了, 吉岡 朋久
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Exploratory Research, Grant-in-Aid for Exploratory Research, Hiroshima University, 2002 - 2003
    アモルファス状態のシリカやチタニアなど酸化物はその分子構造がネットワーク構造を有し,ヘリウムや水素分子のみが透過可能,あるいは,ヘリウムや水素分子すら透過困難な微小な細孔を形成する。このネットワークにはsiOH基あるいはTiOH基が存在し,これらのOH基のHは水素イオンとして拡散移動することが可能であり,高いプロトン伝導性を示すことが示されている。本研究では,シリカあるいはチタニアを用い,プロトン伝導性薄膜の創製を行うことを研究目的としている。プロトン伝導性が発現することが明らかとなれば,プロトン伝導性を有するセラミックスと白金などの電子伝導性材料をナノサイズで並列複合化することで,新規な水素分離膜の創製が可能になると考えられる。 昨年度は,プロトン伝導性薄膜の創製に関する研究を行ない,チタンテトライソプロポキシド(TTIP)とリン酸を出発原料とするチタンリン複合酸化物は,高いプロトン伝導性を有することを明らかとした。 今年度は,ゾルゲル法によりチタンリン複合酸化物をスライドガラス,SUS管,Anodisc,カーボンシート上に製膜する手法を確立した。さらに,表面抵抗および体積抵抗の測定により,温度50-300℃,湿度0-10%におけるプロトン伝導率の評価を行ない,300℃,水蒸気圧50kPaにおいても0.01S/cm程度の高い値を示すこと,150℃では水蒸気が5kPa程度(相対湿度で約1%)で10^<-1>S/cm程度に増加することも明らかとした。高温水蒸気下では,電気伝導率は徐々に低下することが示され,EDX測定より膜中のリンが減少していることが明らかとなった。そこで,製膜直後のチタンリン複合酸化物を水中へ浸漬することによって,膜の安定性が向上することを見出した。

  • Preparation of catalytic membranes with controlled structure and its application to membrane reaction
    TSURU Toshinori, MUTOU Haruhiko, YOSHIOKA Tomohisa, ASAEDA Masashi, YOSHIDA Kazuhiro
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), HIROSHIMA UNIVERSITY, 2001 - 2003
    Catalytic membrane reactors were investigated using two types of catalytic membranes : MFI membranes which had separation ability and catalytic activity in the top layer and silica membranes which had separation ability in the top layer and catalytic activity in the supporting layer. MFI zeolite membranes having different Si/Al ratios were prepared by secondary growth of crystalline colloidal seeds under hydrothermal conditions. An MFI membrane of Si/Al=∞ showed a n-C_4H_<10> permeance of 1.5x10^<-5> m^3(STP)m^<-2>s^<-1>kPa^<-1> and a n/i-C_4H_<10> selectivity of 15 at 150℃. By addition of Al into MFI membranes, the zeolite layers appear to be randomly-oriented and n/i-C_4H_<10> selectivities were decreased. Methylation of toluene using MFI catalytic membrane reactors was carried out from 400-500 ℃. Toluene conversions increased with reaction temperature and p-xylene selectivity achieved was 80 % at maximal, suggesting the effectiveness of MFI catalytic membrane reactors. Methane steam reforming with and without added oxygen was theoretically and experimentally investigated using microporous silica membranes, which allow the permeation of hydrogen as well as other gases in reactants and products. A simulation of catalytic membrane reactors was carried out for a co-current, isothermal, and plug-flow-type membrane reactor with the selective permeation of hydrogen through microporous membranes. Catalytic membrane reactors, consisting of a silica microporous layer and a Ni-catalyst layer, were prepared. Catalytic membrane reactors showing a hydrogen selectivity over nitrogen of 30-100 with hydrogen permeances of 0.5-3x10^<-7> mol m^<-2>s^<-1>Pa^<-1> were applied to the steam reforming of methane with and without the addition of oxygen. The reaction was carried out at 500 ℃, and the feed and permeate pressure were maintained at 100 and 20 kPa, respectively. Methane conversion, X_, increased up to approximately 0.8 beyond the equilibrium conversion of 0.44 by extracting hydrogen in permeate stream.

  • Photocatalytic Membrane Reactors Using Porous Titanium Oxide Membranes
    TSURU Toshinori, YOSHIOKA Tomohisa, ASAEDA Masashi
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Grant-in-Aid for Scientific Research (B), Hiroshima University, 2000 - 2001
    A new type of photocatalytic reaction system in which the titanium dioxide itself is immobilized as a porous membrane capable of not only filtration but also photocatalytic reaction was proposed. The advantages of the system are (1) the forced transport of reactants by convection to TiO_2 membranes ; this would be quite effective for dilute-solution systems where diffusion of reactants limits the total reaction rate, (2) oxidation reaction on the outer and inner surface of porous TiO_2 membranes where high concentrations of OH radicals can be expected, and (3) the possibility to obtain permeate stream oxidized with OH radicals after one-pass permeation through the TiO_2 membranes. Moreover, it is possible to combine selectivity for reactants and products by controlled pore sizes of TiO_2 membranes. For the system of purification of polluted water, purified water would be obtained in the permeate stream by oxidation of pollutants while permeating through the TiO_2 membranes. The decomposition ratio of trichloroethylene (TCE) in permeate stream over that in feed stream was achieved to 60 %, when TGE solutions of approximately 1 ppm was fed to a porous titanium dioxide membrane, that is, the photocatalytic membrane reactor, under blacklight irradiation. On the other hand, no difference in concentration between feed and permeate was observed without the irradiation. Enhanced reactivity with membrane filtration was confirmed in a total recycle system, compared with reaction without filtration.

  • 計算機支援によるガス分離用多孔性セラミック膜のin-situ細孔径評価法の開発
    吉岡 朋久
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Encouragement of Young Scientists (A), Grant-in-Aid for Encouragement of Young Scientists (A), Hiroshima University, 2000 - 2001
    1.透過相互作用エネルギーの評価 本研究では,細孔壁ポテンシャル場によりボルツマン分布則に従ってバルク気相とは密度が異なるガス状分子の細孔内ガス透過モデルを提案した.昨年度の研究により,その妥当性が示された微細孔内ガス透過モデルを用いて,多孔性シリカ膜における数種類のガスの透過速度の温度依存性より透過に有効な細孔表面と透過ガス分子との間に働く引力相互作用を算出すると,二酸化炭素分子の場合で数千から十数J/mol,窒素,アルゴン,酸素分子の場合で数百から数千J/molという値が得られた.膜材料として用いたシリカコロイドから作成した粉体試料において,二酸化炭素および窒素の吸着量を測定すると,同一平衡圧力下において,二酸化炭素の吸着量の方が窒素の吸着量に較べて数倍程度大きく,多孔性シリカ膜におけるガス透過実験から得られた相互作用との定性的傾向の一致が見られた.また,分子動力学法を用いた微細孔内のガス透過シミュレーションにおいても,透過速度から得られた細孔内ポテンシャル場の深さと,実際に設定したポテンシャルパラメータから算出されるポテンシャル場の大きさが定量的に一致し,透過モデルによる相互作用エネルギー評価法の妥当性が示された. 2.平均有効膜細孔径評価法の妥当性の検討 分子種と細孔径に依存する相互作用エネルギーの大きさから細孔径を直接的に評価することは困難であった.しかし,膜細孔内ポテンシャル場を考慮したガス透過モデル式は,細孔構造に由来するパラメータC_pを含み,その値と透過ガス分子径との間に相関関係があることが見いだされた.即ち,ガス透過速度の温度依存性に透過モデル式をフィッティングすることにより得られたC_pの値と透過分子径の関係より,透過に有効な平均細孔径の値を具体的に求めることができた.その結果を,既存の細孔径評価法である,分子プローブ法やナノパームポロメトリによる評価値と比較すると,5〜15Åの平均細孔径を有する複数の膜において良好な一致が見られた.これより,ガス分離に有効と考えられるミクロ孔を有する多孔性シリカ膜において,ガス透過に有効な平均細孔径を,ガス透過実験によりin-situでかつ簡便に評価可能であることが示された.

  • Permeation and separation of organic solvents by porous inorganic membranes
    TSURU Toshinori, YOSHIOKA Tomohisa, ASAEDA Masashi
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Grant-in-Aid for Scientific Research (C), Hiroshima University, 1998 - 1999
    The purpose of the present study is to prepare porous ceramic membranes having various size of pore diameters and investigate the permeation performance of ceramic membranes. Ceramic membranes, which were prepared by sl-gel procedure, We have successfully prepared porous ceramic membranes from silica-zirconia composite colloidal sol solutions We have found that the transport mechanism of liquids through ceramic membrane having relatively large pores (larger than 70 nm) obeys the viscous flow mechanism, while the transport mechanism deviated from the viscous flow mechanism for membranes having smaller pore sizes. The reason was speculated that the affinity between permeating molecules and membrane surface and size plays an important role in determining permeation mechanism. Reverse osmosis experiments were carried out for several types of solutes in ethanol solutions. Solutes sued were n-hexane (CィイD26ィエD2HィイD214ィエD2, molecular weight 86), n-decane (CィイD210ィエD2HィイD222ィエD2, MW 142), and n-teradecane (CィイD214ィエD2HィイD230ィエD2, MW 142) as alkane solutes, and n-hexanol (CィイD26ィエD2HィイD213ィエD2OH, MW 102), n-octanol (CィイD28ィエD2HィイD217ィエD2OH, MW 130), n-decanol (CィイD210ィエD2HィイD221ィエD2OH, MW 1258) and alcohols. Solutes were rejected by porous membranes having pore size smaller than 1 nm. Rejection at 3 MPa and 60℃ ranges from 0.4 to 0.8, depending on the type of molecular weights. We have found that separation of organic molecular mixtures cane be separated by porous ceramic membrane in reverse osmosis. Analysis of transport mechanism suggested that diffusivity in pores was significantly affected by viscosity of solvents in pores.

  • Methane steam reforming by membrane reactor combined with hydrogen separation membranes at high temperature
    ASAEDA Masashi, YOSHIOKA Tomohisa, TSURU Toshinori
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (A), Grant-in-Aid for Scientific Research (A), HIROSHIMA UNIVERSITY, 1996 - 1997
    The purpose of the present study is preparation of hydrogen semi-permeable membranes by sol-gel method and the application of the membranes for methane steam reformig (CH_4=CO+3H_2, CO+H_2O=CO_2+H_2. Methane steam reforming is a reaction governed by the thermodynamic equilibrium where removing one of the products (H_2 or CO,CO_2) could shift the equilibrium conversion. Ceramic ultramicroporous membranes which have permselectivity towards hydrogen were found to be prepared by colloidal routes of silica-zirconia and silica, and found to have excellent stability at high temperature up to 550 ﾟC ; however, the membrane permselectivity decreased with time in steam atmosphere because of further sintering of the separation layr. We have found that firing the coated membranes in steam atmosphere was effective to improve the stability at high temperature (500-570 ﾟC) even in steam atmohsphere. Afterwards, the hydrogen semipermeable membranes were coated with nickel nitrate having catalytic activity for steam reforming to be converted to so-called catalytic membranes, and applied for the methane steam reforming. Without removing hydrogen in the permeate stream, that is, in conventional reaction system, the reaction conversion was 45 %, which was below the equilibrium conversion (65%) at 450 ﾟC.By removing hydrogen from the permeate stream, the conversion increased up to 75%, which clearly shows that catalytic membrane system was effective to shif the apparent equilibrium of the conversion and improve the productivity of the reaction.

  • 無機ナノフィルトレーション膜の開発と有機溶媒中の溶質分離への応用
    都留 稔了, 吉岡 朋久, 浅枝 正司
    日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 広島大学, 1996 - 1996
    ゾル-ゲル法により逆浸透膜と限外濾過膜の中間の分画分子量を有する無機ナノ濾過膜(分画分子量200〜1000)を開発し,無機材料の耐溶剤性を生かした有機溶媒中の低・中分子量物質のナノ濾過分離を行うことを研究目的とする。 まず,シリカ-ジルコニアコロイドゾルの調整条件の検討を行い,5〜100nmの範囲で粒径のそろったゾルの調整方法を確立した。多孔質α-アルミナ管(孔径1μm)を支持管とし,種々の粒径のコロイドゾルを段階的にホットコーティングし,乾燥・焼成することで分離機能性を有するセラミック薄膜の製膜を行なった。 溶媒として種々の分子サイズのアルコール(メタノール,エタノール,プロパノール,ブタノール)を選定し,種々の細孔径(1, 2, 3, 8, 70nm)のシリカ-ジルコニア膜の溶媒単成分の透過実験を20〜60℃の範囲で行った。細孔径70nmの膜の透過流速は,粘度の逆数に対して直線となる粘性流れを示したのに対して,1〜8nmの膜は直線とはならず,粘性流れに従わないことを明らかとした。また,溶媒分子径が大きなほど,細孔径が小さくなるなど,溶媒透過の活性化エネルギーは増加したが,これは細孔との相互作用(分子ふるい性,吸着など)に依存していると考えられる。 低・中分子量物質のモデル溶質として,分子量200〜2000のポリエチレングリコールを用い,メタノール溶媒中での透過実験を行った。細孔径1, 2, 3nmの膜の分画分子量は300, 600, 1000であり,有機溶媒ナノ濾過膜の開発に成功した。また,2nmの膜を用い,エタノールおよびメタノール中での溶質阻止性を検討した結果,大きくは阻止率は変わらないものの,溶媒種に依存していることが示唆された。

  • 高温水素混合ガス分離用多孔性セラミック膜の開発
    浅枝 正司, 吉岡 朋久, 都留 稔了
    Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Priority Areas, Grant-in-Aid for Scientific Research on Priority Areas, Hiroshima University, 1996 - 1996
    本研究の目的は,高温下で安定な水素分離膜を作製し,水の熱化学分解反応を利用した水素製造プロセスであるUT3サイクルへの応用することである。UT3サイクルでは,反応物であるH_2-H_2-HBr混合系から,生成物である水素を300-500℃で効率的に分離精製する必要がある。したがって,分離対象には大量の水蒸気および酸であるHBrが存在するため,耐酸性に優れると考えられるシリカを膜材料として選定した。 種々のシリカ膜を用いてH_2-H_2O-HBr(モル比H_2=70-75%,HBr=1-2%)混合蒸気の分離実験を500℃で行った。H_2が優先透過し,H_2/HBrの分離係数は約100-500を示し,H_2/H_2Oは3-25程度の値を示した。透過係数の順序は,ヘリウム>水素>水>窒素>臭化水素であり,分子サイズに基づく分子ふるいによる分離性が示唆される。温度依存性を検討したところ,ヘリウム,水素単成分は活性化拡散を示し,単成分水素の透過係数は,H_2-H_2O-HBr混合気体での透過係数とよく一致した。水蒸気,および,臭化水素の透過係数の温度依存性は小さかった。また,混合蒸気の分離実験後に純成分気体の透過係数の測定を行ったところ,混合蒸気透過実験前後とほとんど変化しておらず,シリカ膜は酸に対して安定していることが示唆される。 水素/臭化水素透過係数比は水素/窒素透過係数比と強く相関しており,水素/水蒸気透過係数比はヘリウム/水素透過係数比と比較的よい相関を示していた。動的分子径がH_2=2.89,H_2O=2.65,HBr=3.5,N_2=3.64Åであり,HBrとN_2の分子サイズは比較的近接していることから,分離挙動は良い相関を示したと考えられる。臭化水素と窒素は,膜に残存する比較的大きな細孔やピンホール透過し,水蒸気,水素,ヘリウムは微細孔を膜透過していると考えられる。従って,より高選択の水素分離膜を開発するためには,ピンホールの少ない,微細な細孔とする必要があることが明らかとした。

  • 多孔性無機膜における分子透過・分離機構に関する研究
    Competitive research funding

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