Use of cation-exchange membranes for simultaneous recovery of lead and EDTA during electrokinetic extraction

Electrokinetic extraction was tested to remove lead from an Algerian contaminated soil ([Pb] = 4432 ± 275 μg·g−1) located near a battery plant. The enhancement of pollutant removal was achieved by introducing a chelating reagent (disodium salt of ethylendiaminetetraacetic acid, EDTA 0.1 M) in the catholyte. In order to avoid ligand loss, the cell was also modified by adding extra compartments and inserting cation-exchange membranes. Results of contaminant distribution across the soil column showed efficient transport of lead toward the anode, despite a large amount of calcite (25%) and a high acid/base buffer capacity of the sample. Simultaneous recovery of EDTA and lead from their chelated solutions was made possible using the same set-up and by monitoring pH in the circulating fluids.