Title: Removal Properties of Zn from Soil with Extremely Low Hydraulic Permeability by Electrokinetic Method
Abstract: An electrokinetic method with ion exchange reactions was investigated for the remediation of heavy metal contaminated soils which have an extremely low hydraulic permeability. Various consolidated bentonite cakes contaminated with Zn, having different permeation properties, were prepared by a mechanical expression method, and the removal of Zn2+ from the cake was carried out by the electrokinetic method with the addition of Na+. Under the condition of a constant current density, an increase in Na+ concentration led to a higher rejection ratio of Zn2+. However, the permeation rate of the liquid through the cake was decreased with Na+ concentration. Therefore, it is important to select an appropriate concentration of Na+ for the effective removal of Zn2+ from the contaminated soil. Also, the rejection performance was little influenced by the permeability of the cake. Consequently, the electrokinetic method developed in this work was found to be useful for the remediation of contaminated soils with extremely low hydraulic permeability.