Notice of Retraction: Application of Sequential Extraction Analysis to Electrokinetic Remediation of Chromium Contaminated Soil

Abstract

Electrokinetic remediation of chromium contaminated soil is affected by the species of chromium in soil. This work studies the extent of chromium migration and the speciation of chromium during the enhanced electrokinetic remediation process. Two lab-scale electrokinetic experiments were carried out to remediate chromium contaminated soil from a chromite ore processing residue (COPR) deposited site in the northeast of China, using two different solutions (0.2 mol/L sodium acetate and acetic acid buffer solution, 0.1 mol/L sodium citrate and citric acid buffer solution) as catholyte. Each experiment was conducted for 15 days under the application of a voltage gradient of 1.37 V /cm. After remediation, the extent of chromium migration in soil was determined. Speciation of chromium in soil before and after remediation was determined by sequential extraction analyses. The average removal efficiency of total chromium and hexavalent chromium (Cr(VI)) was 11.32% and 81.23% using 0.2 mol/L sodium acetate and acetic acid buffer solution as catholyte. When Using 0.1 mol/L sodium citrate and citric acid buffer solution as catholyte, 21.06% of the initial total chromium was removed and the Cr(VI) removal efficiency was 75.89%. The binding type of chromium with soil was changed from a more difficult extraction type (residual fraction and oxidizable fraction) to easier extraction types (exchangeable and carbonate fraction) after electrokinetic treatment using 0.1 mol/L sodium citrate and citric acid buffer solution as catholyte.