Experimental study on electrokinetic remediation of in-situ Cd contaminated soil by applied voltage

The influence of electrokinetic (EK) process on the removal of cadmium existed in the Cd-contaminated soil of Zhangshi Irrigation Area in Shengyang was discussed under the condition of applied three-level voltages of 15V, 25V and 35V respectively. In addition to monitoring the current, electro-osmotic( EO) flow and electrical conductivity (EC) of the solution in the electrode reservoir(ER) during the experiment, and testing the EC, pH values and the contents of cadmium in the soil at the end of the experiment, the removal efficiency of Cd and energy consumption were calculated. The results showed that the applied voltages not only affected the current, EO flow, conductivity, but changed the removal efficiency of Cd. When the voltages of 25 V and 35 V were applied to remediate the contaminated soil, the removal rate of cadmium was 25.4% and 31.7%, and the magnitude of the energy consumption 68.68 kW·h/g and 188.72 kW·h/g, respectively. It can be concluded that the differences of energy consumption are more significant than that of the Cd removal. The suitable voltage of 25 V is determined by considering the factors of soil properties, treatment time, removal efficiency and energy consumption etc..