Removal of heavy metals from soils using enhanced electrokinetic soil processing

Abstract

In order to remediate contaminated land, a new process of electrokinetic purging of heavy metals from saturated soil is examined by laboratory experiments. Electrokinetic soil remediation is one of the most promising soil decontamination processes as it has high removal efficiency and time-effectiveness in low permeability soils such as clay. Being combined with several mechanisms-electromigration, electroosmosis, diffusion and electrolysis of water, electrokinetic soil processing can remove non-polar organics as well as ionic contaminants. This study suggests that the removal efficiencies for Pb and Cd are significantly influenced by applied voltage and current, type of purging solutions, soil pH, permeability and zeta potential of soil. The removal efficiencies for Pb and Cd were 75-85% for the kaolinite soil and 50-70% for the tailing soil over the duration of 4 days. For heavy metals, their adsorption capacities on the soil surface and mobilities in soil have significant effects on the removal efficiency.