Removal of heavy metals from tap water by a cation exchanger

Selective removal of heavy metals such as Cu, Ni, Co, Mn, Cd, and Pb from tap water that contains relatively high concentrations of calcium and magnesium was carried out with a cation-exchange resin possessing a chelating iminodiacetic acid group. When the concentration of each of these metals in tap water was of the order of a few ppm, their leakage fell below the permitted level in drinking water. Removal of the heavy metals from the resin was successfuly perfomed with 3 M HCl or HNO3.