Soil remediation using an electrokinetic method

Abstract

Abstract Remediation of soils contaminated by heavy metals can be accomplished by subjecting the soil to an electric DC field. The heavy metals that are dissolved will move to either the cathode (mostly) or the anode, depending on their charges. The electrical field also induces electro-osmotic flow that can carry uncharged species. Precipitated and sorbed species will dissolve as the solution is depleted. The acid that is generated at the anode can considerably enhance the dissolution. The acid moves toward the cathode and generates a region with high concentration and mobility of the cationic metals. We present the theoretical basis of the method, the results of some remediation experiments, and the results of some numerical simulations that were used to interpret the experimental results. The remediation experiments are supple mented by determinations of the acid neutralization capacity as well as the sorption capacity and sorption distribution constants for the metal ions. These are essential data for the modelling and can be used to assess whether remediation could be accomplished within a reasonable length of time