PVA hydrogel absorbents for uranium

Polyvinyl alcohol (PVA) based hydrogels have been observed to selectively absorb uranyl ions from phosphoric acid as well as from uranyl nitrate solutions. About 21 % to 40% uranyl ions were taken up by 100 g hydrogel from a solution containing 4.0 ppm to 2160 ppm of uranyl ions. Presence of Cu, Fe, Cd and B ions in phosphoric acid solution did not significantly affect the uptake concentration of uranyl ions. The absorbed ions could be stripped by treatment of loaded gel with either water or nitric acid solutions. Inductive Coupled Plasma Atomic Emission Spectrum [ICP-AES] technique was employed for elemental analysis. It is possible to use hydrogels to extract uranium on large scale. Hydrogels used in the present studies were prepared by radiation processing and contained about 90% water. The selectivity and absorption of ions by hydrogels could be attributed to resistance offered by the hydrophilic pores sizes and their structures as well as size and polarity of the solvated uranyl ion. (author)