Cadmium Removal and Electroosmotic Flow during Electrokinetic Remediation of Contaminated Soil

Electrokinetic experiments were conducted on two type of soil: kaolin and natural clay, to investigate the effects of treatment time and voltage gradient on the electroosmotic flow and contaminants removal. The results show that electroosmotic flow rate increases as the voltage gradient increased both in kaolin and natural clay. The voltage gradient and treatment time have also a pronounced effect on the migration of Cd in kaolin. The extent of Cd migration towards the cathode increases with the increasing of applied gradient or tests time. However, a high concentration of Cd was found near the cathode due to adsorption of Cd in the high pH condition. Electroosmotic flow from the anode toward the cathode promotes the development of a low pH environment in the soil and groundwater and in turn enhances the removal of the contaminants.