Influence of Complex on Electrokinetic Remediation of Zinc Contaminated Soil

The efficiency of electrokinetic remediation of zinc contaminated soils and the influence of complex EDTA were researched by means of experiment for the complicated remediation of soil contaminated by typical heavy metal in this paper, and migration and variation characteristics of zinc were analyzed too. The experimental results indicated that the heavy metal pollutant could be enriched and removed in the vicinity of electrode, and pH value in soil was the key factor which affected the efficiency of electrokinetic remediation. The pH value varied obviously during the electrokinetic remediation because of the oxidation and reduction near the electrodes, and the pH value near the positive electrode varied from 6.3 in initial stage to 3.2 at later stage, and the pH value was on the contrary near the negative electrode, namely, varied from 6.4 in the beginning to 9.8 in the last, which made known that the condition of acidity and alkalinity in soil varied clearly. And the pollutant zinc could be enriched near the cathode and the migration orientation of heavy metal was from the anode to cathode, which indicated that the effect of zinc migration was enhanced under the electric field. The removal efficiency of zinc in the soil near the positive electrode was 61.7% when the experimental voltage was 0.5 V/cm. But the contrast experimental results, in which EDTA solutions with concentrations of 0.005 mol·L^-1 and 0.01 mol·L^-1 were added in contaminated soils, indicated that the removal efficiencies of zinc in the soil near the positive electrode were increased and up to 75.2% and 83.6% respectively obviously at the same level of voltage, and the migration orientation of heavy metal was altered and from the cathode to anode.