URANIUM SORPTION BEHAVIOR OF A MACROPOROUS, QUATERNIZED POLY(4-VINYLPYRIDINE) RESIN IN SULFURIC-ACID MEDIUM

A newly available, macroporous anion-exchange resin Reillex(TM) HPQ, based on a copolymer of quaternized 4-vinylpyridine and divinylbenzene, has been used in the sulfate form for the sorption of uranium from acidic sulfate solution. Comparative data for uranium sorption capacity, selectivity and kinetics in sulfuric acid media are presented for this new resin and two other common anion-exchange resins Reillex(TM) HP and Dowex 1-X8, all used in the sulfate form. Containing both strong-base (approximately 70%) and weak-base sites (approximately 30%), the HPQ resin shows a combined behavior of strong-base and weak-base resins. The new resin thus exhibits less sensitivity to pH in the range 2-4, high sorpion capacity and high selectivity for uranium in acid media against a high salt background and in the presence of Fe(III). Both HP and HPQ have slower sorption kinetics than Dowex-1, the t1/2 values, for example, being 23, 21 and 10 min, respectively, at a substrate concentration of 2.5 mmol U/l. The uranium stripping, however, has significantly faster kinetics on HPQ as compared to HP and Dowex-1, the t1/2 values being 3, 7 and 18 min, respectively, with 2 N H2SO4 as the stripping agent.