The effect of gel composition on the uranyl ions adsorption capacity of poly(N-vinyl 2-pyrrolidone-g-citric acid) hydrogels prepared by gamma rays

Poly(N-vinyl 2-pyrrolidone-g-citric acid) (PVP-g-CA) hydrogels with varying compositions were prepared from ternary mixtures of N-vinyl 2-pyrrolidone–citric acid–water by using 60Co γ-rays. The effect of gel composition on the uranyl ions adsorption capacity of PVP-g-CA hydrogels was investigated. Uranyl adsorption capacity of these hydrogels were found to be in the range of 18–144 mg [UO]/g dry gel from the aqueous solution of uranyl nitrate and 22–156 mg [UO]/g dry gel from the aqueous solution of uranyl acetate, depending on the content of citric acid in the hydrogel, while poly(N-vinyl 2-pyrrolidone) hydrogel did not sorb any uranyl ion. The swelling of PVP-g-CA hydrogel containing 2.7 mol % CA was observed in water (1620%), in uranyl acetate solution (1450%) and in uranyl nitrate solution (1360%), as compared to 700% swelling of pure PVP hydrogels. The diffusion coefficients were varied from 12.57 up to 4.04 • 10−8 m2 s−1.