The Combined Electrokinetic and Flushing Remediation of Multiple Heavy Metals Co-contaminated Soil Enhanced with Acid Treatment

Jun Hou,¹ Li Fan,^1,2,* Mingyuan Zhou,^1,2 Xuefeng Zhu,^1,2 Xiuli Li,^1,2 Jie Guan,^1,2 Guilan Gao^1,2 and Fengying Fu¹

¹School of Environmental and Materials Engineering, Shanghai Polytechnic University, Shanghai 201209 China

²Research Center of Resource Recycling Science and Engineering, Shanghai Polytechnic University, Shanghai 201209 China

*E-mail: fanli@sspu.edu.cn

ABSTRACT

Electrokinetic remediation 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 co-contaminated 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 result 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 experimental results demonstrated 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.

Keywords: Electrochemistry; Environmental remediation; Heavy metals; Pollution control