Preparation of the fibrous adsorbent containing amidoxime group and adsorption property for uranium

A fibrous adsorbent containing amidoxime group (AO-fiber) was made of comercial polyacrylonitrile fiber by reaction of hydroxylamine in order to obtain a new fibrous adsorbent for the extraction of uranium from sea water. The infrared spectra of AO-fiber exhibited the characteristic absorption of amidoxime, i.e. amine stretching absorption at 3400 cm-1, OH stretching at 3320 cm-1, CN stretching of the hydroxyimino group at 1650 cm-1 and NO stretching of the hydroxyimino group at 930 cm-1. The sum of the adsorption capacities of acid and alkali on the AO-fiber coincided with the amount of hydroxylamine formed by acid hydrolysis, and showed linear correlation with the adsorption capacity of Cu(2). On the other hand, the adsorption capacity of acid on the AO resin was in accord with the adsorption capacity of Cu(2). Based on these observations, formation of another functional group, i.e. hydroxamic acid was assumed in addition to hydroxylamine in the AO-fiber. Capability of uranium adsorption of the AO-fiber increased with increasing the adsorption capacity of Cu(2) when prepared from the same raw material of polyacrylonitrile fiber. The maximum amount of the uranium adsorption from sea water was 100 μg/g for a week. (author)