Remediation of soil co-contaminated with decabromodiphenyl ether (BDE-209) and copper by enhanced electrokinetics-persulfate process.

This work investigated the influences of citric acid and methyl-β-cyclodextrin (MCD) as enhancing agents during the electrokinetics (EK)-persulfate process on the remediation of soil artificially contaminated with decabromodiphenyl ether (BDE-209) and copper (Cu) with an initial concentration of 50 and 1000 mg/kg, respectively. The results clearly demonstrate the efficiency of the process while at the same time, the distribution of the residual contaminants in soil and the EK parameters were greatly influenced by the presence of persulfate, MCD and citric acid. The results show that there was significant removal of BDE-209 and Cu from the soil. MCD-assisted process gave the highest BDE-209 removal (88.6%) and the third largest Cu removal (54.3%) from the soil. Comparatively, the highest Cu removal (92.5%) and the second largest BDE-209 removal (85.6%) were achieved by the joint application of MCD and citric acid in anolyte during the EK-persulfate treatment. MCD and citric acid could increase soil electrical current and electroosmotic flow during EK. The alkalization of soil near cathode was alleviated by the acidic byproducts of persulfate decomposition which could be transported to the soil by electroosmosis and electromigration. This integration process may provide a green efficient technology for remediating co-contaminated soil.