| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1990: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1989: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Research Abstract |
In order to develop artificial materials available for the selective separation of the nitrate ion from environmental water, cyclodextrins, cyclic oligosaccharides, were chemically modified with pyridinio or butylamino groups, and the host compounds were further modified to be solubilized in organic media or to be immobilized on polymers.
1) Mono-[6-(1-pyridinio)-6-deoxy]-cyclodextrin was perbenzoylated to give a host compound soluble in chloroform. An ability of the host to bind inorganic anions, including the nitrate ion, was uantitatively evaluted in chloroform. The nitrate ion was bound to the perbenzoylated host much more strongly than other inorganic anions common in environmental water.
2) Mono-[6-(1-pyridinio)-6-deoxy]-cyclodextrin was immobilized on bridge type or pendant type polymers, and the adsorption of the nitrate ion on the host polymers was examined in an aqueous solution. The nitrate ion was strongly adsorbed on the host polymers with the Langmuir-type adsorption isotherm. However, the maximum amount of adsorption was less than the polymer are not always exposed to the nitrate ion in water.
3) All the C(6)-OH groups of cyclodextrins were replaced with butylamino groups, and an ability of the resulting hosts to bind the nitrate ion was examined in an acidic aqueous solution. The binding constant for a host-nitrate ion system was unsatisfactorily small, though it was about 50 times that for a unmodified cyclodextrin-nitrate ion system. On the other hand, the host bind the sulfate ion very strongly in an acidic aqueous solution.
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