Efficient uptake of perrhenate/pertechnenate from aqueous solutions by the bifunctional anion-exchange resin

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 ReO(4)(-)from aqueous solution within 150 min and the maximum sorption capacity for ReO(4)(-)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-.