Combination of Electrokinetic Separation and Electrochemical Oxidation for Acid Dye Removal from Soil

The remediation of kaolin soil contaminated with Acid Blue 25 was performed by a combination of electrokinetic separation and electrochemical degradation. The anionic dye was removed from the soil mainly by electroosmosis towards the cathode, with up to 89% removal being achieved at 30mA for 7 days. The dye solution was completely mineralized in a separate electrochemical oxidation process using a boron-doped diamond anode. A NaCl solution enhanced the oxidation rate of the dye through indirect oxidation mediated by active chlorine, as well as direct oxidation. The results demonstrate that complete removal of dye from soil can be achieved by electrokinetic separation followed by electrochemical oxidation of effluent with a chloride-containing electrolyte.