Response Surface Method Analysis on Electro-Enhanced Technique for Remediation of Cadmium Contaminated Soil

Abstract

In view of the problems of long remediation time, high energy consumption and low remediation efficiency in electrokinetic remediation of heavy metal contaminated soil, Cd was used to simulate heavy metals in contaminated soil, and response surface method (RSM) was used to optimize the factors influencing electrokinetic remediation. Central Composite (CCD) experimental design method was taken to study the effects of electric field strength, remediation time and water content on removal rate of Cd in soil. Also, polynomial regression mathematical model and optimal reaction conditions were provided for Cd pollution in electrokinetic soil remediation. The simulated equation F was 15.67, the correlation coefficient was 0.9338, and the adjustment correlation coefficient was 0.9042, indicating good regression and strong significance of the equation. The model results showed that, for the optimal experimental conditions, electric field strength was 2.25V·cm-1, the remediation time was 120.79h, and the water content was 17.06%. On the basis of such reaction condition, intermittent current flow method was adopted d to further enhance the electrokinetic remediation effect. The cadmium removal rate in the soil was increased by 3.17%, 2.86% and 2.43%, respectively, and the electric energy consumption was decreased by 10.54%, 11.28% and 9.97%, respectively, suggesting that the method could effectively improve the removal rate of Cd and reduce energy consumption.