| Project/Area Number |
09650840
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
反応・分離工学
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| Research Institution | TOKYO INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
TAKESHITA Kenji Tokyo Institute of Technology, Interdisciplinary Graduate School of Science & Engineering, Associate Professor, 大学院・総合理工学研究科, 助教授 (80282870)
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| Co-Investigator(Kenkyū-buntansha) |
TAKAHASHI Toshio Lion Corporation, 物質化学センター, 副主席研究員
NAKANO Yoshio Tokyo Institute of Technology, Interdisciplinary Graduate School of Science & En, 大学院・総合理工学研究科, 教授 (30092563)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥2,700,000 (Direct Cost: ¥2,700,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | extraction / lanthanide elment / mutual separation / gel / thermosensitive gel / phase transition / phosphoric acid ester / thermal swing / リン酸ジエステル / アルキル基 / 立体障害 / イオン認識 |
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| Research Abstract |
The extraction of lanthanide ion between an aqueous solution and a thermosensitive polymer gel, n-isopropylacrylamide (NIPA) gels copolymerized with 2-metacrloxyethylacidphospate (MR) was examined. This polymer gel shows a phase transition phenomena, that is, the structure of gel changes from swelling to shrinking with increasing temperature. The extraction equilibrium of lanthanide ions, La(III) and Sm(III), in an aqueous solution was measured batchwise. The distribution ratio, Kd, increased with increasing temperature. These metal ions can be extracted in the gel at the shrinking condition and cluted by the conformation change of polymer network from shrinking to swelling of gel with decreasing temperature.
The extraction mechanism of lanthanide ion, which was estimated from the pH-dependency on Kd, was described simply as
Ln^<3+> + 3 RH <double arrow> LnR_3 + 3 H^+
at both the shrinking and swelling conditions. The number of effective phosphorus molecules for the extraction of lanthanide ion, which was derived from the extraction constants at the shrinking and swelling conditions corresponded to about 80% of copolymerized phosphorus molecules at the shrinking condition and was reduced to about 30% at the swelling condition.
The thermal swing tests were carried out to examine the possibility of practical use. It is important practically to maintain the extraction capability of gel in a long-term use. The temperature-dependency of Kd was maintained for repcating the extraction and elution by the thermal swing operation. These results suggest that the phase transition phenomena of thermosensitive gel is applicable to the extraction and elution operations of metal ion.
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