Abstract
In this work, batch experiments were carried out to explore the sorption properties for perrhenate (ReO4−, a surrogate for TcO4−) by two types of commercial bifunctional anion-exchange resins (Purolite A530E and A532E). It is found that these two bifunctional anion-exchange resins could rapidly remove ReO4− from aqueous solution within 150 min and the maximum sorption capacity for ReO4− reached as high as 707 and 446 mg/g for Purolite A530E and A532E, respectively. The sorption properties were independent of pH over a wide range from 1 to 13. More importantly, both Purolite A530E and A532E exhibited excellent selectivity for the removal of ReO4− in the presence of large excess of NO3− and SO42−. Finally, the removal percentage of ReO4− by these two resins could be >90% and 80%, respectively, from the Hanford low-level waste melter off-gas scrubber simulant stream. Such high selectivity of Purolite A530E and A532E for the removal of ReO4− might be due to the presence of the long-chain group of –[N(Hexyl)3]+, which favored hydrophobic and large anions such as ReO4−/TcO4− rather than NO3−.