Sorption and Desorption of Perchlorate with Various Classes of Ion Exchangers: A Comparative Study

This study compares representative standard strong-base anion (SBA) and weak-base anion (WBA) exchangers, a bifunctional resin (A-530E), a class of polymeric ligand exchangers (PLEs), and an ion-exchange fiber (IXF) with respect to perchlorate sorption capacity, kinetics, and regenerability. While A-530E offered the greatest perchlorate capacity and selectivity, practically acceptable capacity was also observed for styrenic SBA and WBA resins, a PLE, and IXF. In contrast, polyacrylic resins offered much lower perchlorate capacity. The greater capacity of styrenic resins is attributed to enhanced ion-pairing and Lewis acid−base interaction due to the hydrophobic nature of polystyrene matrices and lower hydration energy of perchlorate. Conversely, regeneration of polyacrylic resins was much more efficient, and A-530E was least regenerable. IXF offered comparable perchlorate capacity to that of styrenic resins yet unparalleled kinetics (with a sorption equilibrium time of <1.5 h), and much greater regeneration efficiency, and WBA resins were much more regenerable than SBA resins.