Basic Study on Uranium Extraction from Sea Water, (II): Extraction of U(VI) by Polyacrylamide Gel Containing Various Metal Hydroxides

The possibility was examined of extracting U (VI) from sea water by adsorption on gel particles containing various metal hydroxides, including Ti(OH)4 and Zn(OH)2, dispersed in Polyacrylamide gel particles. The hydroxide adsorbent thus prepared in gel form was packed in a column for processing the sea water (both sea water sampled from harbor and artificially prepared solution). The U(VI) collected in the column was eluted with 0.10 M Na2CO3 solution. Factors affecting the performance of the hydroxide adsorber were examined: The kind of metal hydroxide used, the degree of cross-linking of the Polyacrylamide, the content of hydroxide in the gel and the concentration of U (VI) in the original sea water. Of the five kinds of metal hydroxides tried, only titanium hydroxide was found to function usefully as adsorbent for the U(VI). The degree of Polyacrylamide crosslinking was found have no relation to adsorption performance, which, on the other hand, was significantly influenced by changes in titanium hydroxide in the gel: The amount of U (VI) adsorbed reached a maximum at 2 mg Ti/ml gel. Also, the adsorption improved consistently with decreasing concentration of U (VI) contained in the original sea water, down 10−6 M.