Removal of trace concentrations of heavy metals using complexing ion-exchange resins

Oak Ridge National Laboratory is examining potential new technologies for treating radiologicallycontaminated process wastewater. The current treatment facility is aging and is optimized to remove 90 Sr, but future wastewaters are likely to contain mostly activated metals, such as 51 Cr and 64 Cu. Other lowvolume wastewaters may contain trace concentrations of Hg and U. Complexing ionexchange resins and other specialized sorbents were tested for removing trace concentrations of heavy metals. Shortterm column tests and batch loading tests were conducted using a surrogate wastewater and various sorbents. These tests showed that metal uptake was very rapid, and that good removal and relatively high loadings could be achieved from a very dilute wastewater surrogate. Forager MTU (Dynaphore, Inc.) showed the best overall results, removing 91.9% of the Cr, 99.3% of the Cu, ≥99.7% of the Hg, and ≥99.9% of the U with a contact time of 120 seconds in a shortterm column test.