The Combined Electrokinetic and Flushing Remediation of Multiple Heavy Metals Co- Contaminated Soil Enhanced with Acid Treatment
Abstract
Electrokinetic remediation(EK) is widely regarded as a green technology applied to deal with the contaminated soil. However, the treatment efficiency of EK is particularly dependent on the desorption of contaminants from the soil. In this work, the electrokinetic remediation of soil cocontaminated with Cd, Cu and Pb enhanced with acid pre-treatment and the EDTA-2Na flushing was studied. A series of experiments were conducted to investigate the removal behavior of heavy metals from soil with different voltage gradients, electrode materials and concentrations of EDTA-2Na. The results included the following main aspects: 1) Under the voltage gradient of 1.0 V/cm, the removal efficiency of Cd, Cu and Pb reached 91.09 %, 80.34 % and 72.38 %, respectively. Compared to the other studies, the electric current was particularly high since the soil was pre-acidified. 2) The residual form of heavy metals in the soil was transformed to the other fractions easier to be removed due to the function of EK and EDTA-2Na flushing. 3) The removal of Cd, Cu and Pb was mainly influenced by the electromigration under this experimental condition. A combined electrokinetic and flushing remediation enhanced with acid treatment process was found to be effective for Cd, Cu and Pb removal simultaneously.
