Effect of pH on the adsorption of selected heavy metal ions from concentrated chloride solutions by the chelating resin Dowex M-4195

The effect of pH on the adsorption of nickel (II), copper (II), cobalt (II), lead (II), manganese (II), and iron (III) from concentrated chloride solutions onto Dowex M-4195 is reported for the first time. This chelating resin has an unusual ability to adsorb many of these metals, most notably copper, even at very low pH. The selectivity for many of these metals makes this resin particularly attractive for detoxifying concentrated acidic chloride solutions generated during the processing of many manganese ores and minerals. The uptake behavior at these high-chloride concentrations differs somewhat from that at the lower chloride concentrations previously reported in the literature. The behavior is discussed in terms of the chemistry of the bis(2-pyridylmethyl)amine (hispicolylamine) functional group.