| Project/Area Number |
08454234
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
分離・精製・検出法
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
OKADA Tetsuo Tokyo Institute of Technology, Department of Chemistry, Associate Professor, 理学部, 助教授 (20183030)
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| Co-Investigator(Kenkyū-buntansha) |
OGUNI Masaharu Tokyo Institute of Technology, Department of Chemistry, Professor, 理学部, 教授 (50144423)
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| Project Period (FY) |
1996 – 1997
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| Project Status |
Completed (Fiscal Year 1997)
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| Budget Amount *help |
¥7,500,000 (Direct Cost: ¥7,500,000)
Fiscal Year 1997: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1996: ¥6,300,000 (Direct Cost: ¥6,300,000)
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| Keywords | Ion-exchange / Solvation / Electrostatic Potential / Separation / 非水溶媒 |
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| Research Abstract |
Two approaches have been investigated to elucidate ion-exchange separation selectivity. One is the elucidation of the solvation of ions in the resin. The other is physical modeling of separation behaviors. The solvation of ions in ion-exchange resin was studied basically by changing solvents and the structures of ion-exchange sites. Studies on anion-exchange indicated that the solvation of ion-exchange sites is not important in the determination of overall separation selectivity, while the solvation of counterious is very important. The separation selectivity of ions can be basically explained by ion-pair formation between ion-exchange sites and counterions. This result was included in a novel physical model for ion-exchange based on electrostatic theories. Starting from the Poisson-Boltzmann equation, some equations capable of explaining various phenomena occurring at the interface between ion-exchange resins and solution were derived. The complex formation of polyethers with ammonium ion chemically bonded on silica gel, the complexation of polyethers with countercations in cation-exchange resins, and usual ion-exchange separation were very well explained by developed models. Results strongly suggest that ion-pair formation, specific adsorption of ions, and the accumulation of ions in electrical double layr play decisive roles for the determination of ion-exchange selectivity.
In addition, capillary electrophoresis of Bronsted acids as heteroconjugated anions and effects of ultrasound on ion-exchange have been also studied. Reliable heteroconjugated anion formation constants can be determined for various combination of Bronsted acids with anions by the developed mthod. In addition, it was shown that ultrasound can be used as external stress to vary and modify the separation selectivity. This effects of ultrasound is caused by local temperature increases induced by the transmission of acoustic pressure.
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