Optimization of electroosmotic flow to enhance the removal of contaminants from low permeable soils

Electrokinetic is the effective method for the extraction of contamination from low permeable soil. This work examines the influence of calcium ions on the electroosmosis, and the effects of electric potential, current, and pH variation on the removal of Pb 2+ , Na + , and Clˉ ions from artificially contaminated soil during vertical electrokinetic experiments. The DC electric field of 1V/cm was applied across the soil specimen via steel mesh electrodes for 24, 48 and 72 hours of experiment. The outcomes show that the formation of acidic and alkaline environments in soil specimens affects the transport of ionic charge species by reducing the effect of electroosmosis. To enhance the electroosmotic flow, the anode reservoir filled with and without calcium chloride solution was examined. The enhancement of electroosmosis using calcium ions as an electrolyte increased the extraction efficiency of Pb 2+ and Na + ions instead of the Clˉ ions due to the high electroosmotic flow from anode to cathode. For relatively low electroosmotic flow, the removal rate of Clˉ ions was higher than the Pb 2+ and Na + ions. The results demonstrated that the extraction efficiency was increased with an increase in the treatment time. To avoid the dryness of the soil surface, wet sponges were inserted at the anode side, which connected with the electrolyte.