1987 Fiscal Year Final Research Report Summary
Development of ion-permselective piezodialysis membranes
| Project/Area Number |
60470066
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
工業分析化学
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| Research Institution | Kyushu University, Faculty of Engineering |
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Principal Investigator |
TAKAGI Makoto Kyushu University, Faculty of Engineering, 工学部, 教授 (90037739)
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| Co-Investigator(Kenkyū-buntansha) |
OHKI Akira Kagoshima University, Faculty of Engineering, 工学部, 助手 (20127989)
NAKANO Koji Kyushu University, Faculty of Engineering, 工学部, 助手 (10180324)
TAKENAKA Shigeori Kyushu University, Faculty of Engineering, 工学部, 助手 (60188208)
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| Project Period (FY) |
1985 – 1987
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| Keywords | piezodialysis / polymer membrane / reverse osmosis / separation of metal ions / solvent extraction / adsorption of metal complex ion / 分子認識 |
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| Research Abstract |
Piezodialysis membranes with ion-selective permeability were developed. The basic strategy for the development was as follows: 1. Metal ions in aqueous solution are complexed with halide or pseudo-halide anions to produce charge neutralized or anionic metal complexes. 2. The neutral complexes are sorped (extracted) and concentrated onto the membrane phase, while anionic complexes are similarly sorpted by forming ion-pair complexes with appropriate cations in solution. 3. The sorped metal species then permeate the membrane under coupling with a solvent flow through the membrance under hydraulic pressure.
This is a new concept of ion-selective piezodialysis, where the skin layer of dialysis membrane assumes the role of organic solvents in conventional solvent extraction and the metal selectivity in solvent extraction is extended to ion-selective piezodialysis.
The above concept was experimentally realized with cellulose acetate (CA) membranes. Though CA is a solid polymer, it sorped metal complexes just like ordinary organic solvents of related chemical structure like methyl isobutyl ketone and dlycerol triacetate. As an example, the ease of CA membrane permeation by thiocyanate complexes was in the order, Zn>In>Fe(III)>Cd>Ni. A variety of other polymer materials was tested, but the metal selectivity was generally similar to CA, and the permeability was inferior to the case of CA. In order to search for new metal sorption selectivity to organic media, several basic approaches were made which included the use of liquid crystals as extraction media and the use of the concept of molecular recognition of ion-pair entity in solvent extraction systems.
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