A model for evaluating the feasibility of an extraction procedure for heavy metal removal from contaminated soils

A model was developed that allowed for the evaluation of a soil metal clean ing technique in a rapid and cost effective manner. Metal flow (Pb, Cu, Zn, and Cd) during a counter-current soil-acid extraction procedure, consistin g of a decarbonation, solubilisation, and washing step, was determined. Req uired input data are total soil metal content and metal equilibrium distrib ution coefficients, derived from batch equilibration experiments. The model was calibrated and validated against experimentally obtained results. Mode l predictions adequately described metal behaviour and removal in each of t he extraction steps. Based on the results, optimum operating conditions for the steps involved in the extraction procedure were determined and the fea sibility of the counter-current extraction procedure for heavy metal remova l from a contaminated soil evaluated.