Chelates enhanced electrokinetic remediation by conditioning catholyte pH

Electrokinetic extraction has been proved to be a very effective technology in cleaning up heavy metal contaminated soils. The main mechanisms of contaminants movement in the electrokinetic technology are electromigration of ionic species and electroosmosis. The feasibility of using chelate agents to enhance the electrokinetic remediation of heavy metal contaminated soils has been investigated in this study. Three parts of experiments were conducted to evaluate the influence of acetic acid, citric acid and pyridine-2,6-dicarboxylic acid (PDA) as washing and purging solutions on the enhancement of the removal of cadmium. At test I(A) water was used for soil saturation and acetic acid was used as purging solution in the electrode compartments. This test served as a baseline for test I(B) while acetic acid was used for soil saturation. At test II(A), the soil was saturated with water and citric acid was used as purging solution. At test III(A) water was used for soil saturation, PDA as purging solution and, this test served as a baseline for test III(B), while PDA was used for soil saturation.