Removal of Pb from a calcareous soil during EDTA-enhanced electrokinetic extraction.

Electrokinetic extraction has been tested to remove lead from an Algerian contaminated soil ([Pb] = 4.432 +/- 0.275 mg g(-1)) sited near a battery plant. The effect of EDTA at various concentrations (0.05-0.20 M) on the enhancement of lead transport has been studied by applying a constant voltage corresponding to a nominal electric field strength of 1 V cm(-1) (duration: 240 h). Results of contaminant distribution across the experimental cell have shown efficient transport of lead toward the anode despite the presence of calcite (25%) and the high acid/base buffer capacity of the soil. To avoid ligand loss, which would be anodically oxidized, the cell was modified by adding extra compartments and inserting cation exchange membranes (Neosepta CMX). Thus, simultaneous recovery of EDTA and lead from their chelated solutions has been made possible using the same set-up and by controlling fluids chemistry.