Exhausting and regenerating resin for uranium removal

Abstract

As expected, lowering the pH adversely affected uranium removal by anion resin—but at a lower than anticipated pH.Uranium removal with chloride‐form anion exchange resin was studied near Houston, Texas, where an abandoned water supply well contained 120 μg/L uranium and 25 pCi/L radium. With this neutral‐pH, sulfate‐free water, the resin exhibited enormous capacity for the uranyl tricarbonate complex, still removing 95 percent uranium after nearly 16 months without regeneration and after 302,000 bed volumes of throughput. Computer predictions indicate, however, that the presence of sulfate in feedwater would significantly shorten the run length. The efficiency of uranium removal did not deteriorate at a feed pH as low as 5.6, but when the pH was lowered to 4.3, uranium removal decreased to 50 percent and the run length was shortened to 5,000 bed volumes. Results indicate that sodium chloride (NaCl) was an adequate regenerant and, within the range of 0.5 to 4.0 N, the more concentrated the NaCl, the more efficient it was.