Influence of complexing agents on the removal of metals from water by a cation exchanger

Selective removal of metals such as Cu, Ni, Co and Cd from tap water contai ning small amounts of complexing agents such as humates and salts of carbox ylic acid was carried out with a cation-exchange resin possessing a chelati ng iminodiacetic group. Some of the complexing agents investigated had litt le effect on leakage, and eluate residues remained below levels permitted f or drinking water; other agents (e.g., EDTA) affected the process significa ntly. Removal of the metals from the resin was successfully performed with 3N HCl or HNO3.