IMPROVEMENT IN ELECTROKINETIC REMEDIATION OF LEAD CONTAMINATED SOILS WITH SINGLE PASS SOIL WASHING AND APPROACHING ANODES

The soils contaminated by Pb near a mine tailing were remedied via an improved electrokinetical method utilizing single-pass soil washing and approaching anodes (AAs). The variations of the removal efficiency and the soil pH as a function of the treatment time were determined. The maximum Pb removal efficiency was found to be as high as 63.1% under a voltage gradient of 1 V/cm for 48 hours; in contrast to 31.5% when the electrokinetic remediation with AAs without soil washing was employed. After single-pass soil washing, the rate of water content of soil increased to more than 80%, which is very suitable for electrokinetic remediation, at the same time, more ions were desorbed from the soil particles. The mechanism of Pb electromigration behavior in soils during an enhanced EK method is described as the elution in an electrokinetically driven chromatogram.