Removal of Perchlorate from Contaminated Water Using a Regenerable Polymeric Ligand Exchanger

A polymeric ligand exchanger (PLE), DOW 3 N‐Cu, has been investigated for perchlorate (ClO 4 − ) removal from contaminated water. Batch kinetic tests revealed that the perchlorate sorption equilibrium for DOW 3 N‐Cu can be reached within 20 hours and perchlorate removal by DOW 3 N‐Cu follows standard ion exchange stoichiometry. Fixed‐bed column runs showed that 12,388 bed volumes of perchlorate‐free water can be obtained when DOW 3 N‐Cu was used to treat a simulated contaminated water with an influent perchlorate concentration of 200 µg/L. It was found that the regeneration of spent DOW 3 N‐Cu is pH dependent. It was shown that addition of ethanol and a surfactant Tween 80 to a 4% NaCl/2% NaOH regenerant solution increased the regeneration efficiency of spent DOW 3 N‐Cu by 11 and 5 percent, respectively. Nearly 90% of perchlorate capacity of saturated DOW 3 N‐Cu was recovered using 35 bed volumes of a regenerant containing 4% (w/w) NaCl, 2% NaOH, 5% Tween 80, and 5% ethanol.