The removal of toxic metals from liquid effluents by ion exchange resins. Part IX: Lead(II)/H plus /Amberlite IR-120

Lead is recognized as a highly harmful metal for humans, thus its removal from any source containing it is a primary target. In average conditions, lead is present in aqueous solutions of pH lower than 5-6 as the cation Pb2+, thus in this work, the removal of such cation from aqueous solutions by the resin Amberlite IR-120 was investigated. Experimental variables than may influence to the removal of the metal were considered: stirring speed of the solution-resin system, temperature, resin dosage and resin particle size, and aqueous pH values. The metal uptake equilibrium responded well to the Freundlich isotherm, being endothermic and non-spontaneous, whereas lead uptake onto the resin responded to the pseudo-first order kinetic model; moreover, the uptake mechanism is non-dependent of the resin particle size and fits well to the aqueous diffusion model. The removal of lead(II) within the resin compared favourable to that obtained with multiwalled carbon nanotubes, and also with respect to the loading of several base metals from binary solutions loading experiments. Lead loaded onto the resin can be eluted, generally in almost quantitative form, by HCl solutions, under different experimental conditions