Sorption and desorption of perchlorate and U(VI) by strong-base anion-exchange resins

This study investigated the sorption affinity and capacity of six strong-base anion-exchange (SBA) resins for both uranium [U(VI)] and perchlorate (ClO4-) in simulated groundwater containing varying concentrations of sulfate (SO42-). Additionally, desorption of U(VI) from spent resins was studied to separate U(VI) from resins with sorbed ClO4- for waste segregation and minimization. Results indicate that all SBA resins investigated in this study strongly sorb U(VI). The gel-type polyacrylic resin (Purolite A850) showed the highest sorption affinity and capacity for U(VI) but was the least effective in sorbing ClO4-. The presence of SO42- had little impact on the sorption of U(VI) but significantly affected the sorption of ClO4-, particularly on monofunctional SBA resins. A dilute acid wash was found to be effective in desorbing U(VI) but ineffective in desorbing ClO4- from bifunctional resins (Purolite A530E and WBR109). A single wash removed similar to75% of sorbed U(VI) but only similar to0.1% of sorbed ClO4- from the bifunctional resins. On the other hand, only 21.4% of sorbed U(VI) but similar to34% of sorbed ClO4- was desorbed from the Purolite A850 resin. This study concludes that bifunctional resins could be used effectively to treat water contaminated with ClO4- and traces of U(VI), and dilute acid washes could minimize hazardous wastes by separating sorbed U(VI) from ClO4- prior to the regeneration of the spent resin loaded with ClO4-.