Enhancement of electrokinetic remediation of lead and copper contaminated soil by combination of multiple modified electrolyte conditioning techniques

Abstract

Electrokinetic soil remediation is often impeded by the aggregation of small particles, within soil, during the procedure. The soil porous network is subsequently clogged which results in immediate process termination. In order to overcome this limitation, the feasibility of electrokinetic remediation coupled simultaneously with two enhancing techniques was investigated: modified periodic polarity reversal and catholyte pH control. The objective is to keep the soil pores unclogged in order to remove Pb and Cu from soil. Citric acid was used as anolyte, and 1 DCV.cm-1 was applied through the processing cell. This strategy showed 9.0 times better remediation results than that of unenhanced electroremediation. It was mainly owed to: (i) The pH adjustment that kept the catholyte ideally acid, thus avoiding the formation of metal hydroxide precipitates that could clog the soil pores. (ii) An increase of electro osmotic flow due to the modified polarity reversal technique. Approximately 96% of Pb and Cu were removed from soil. Duplicate results were obtained on soil with 10-fold the initial heavy metals concentration. This combined configuration ensured an unclogged path within soil and enhanced electrokinetic mechanisms efficiency against pollutants remediation.