Electrokinetic Remediation of Chlorinated Aromatic and Nitroaromatic Organic Contaminants in Clay Soil

Abstract

This article presents a bench-scale experimental study performed to investigate the remediation of low permeability clay soil contaminated with pentachlorophenol (PCP), Lindane, and dinitrotoluene (DNT) using electrokinetic technique. Three bench-scale electrokinetic experiments were conducted on kaolin soil. In each test, the soil was spiked with one of the following contaminants: PCP, Lindane, and DNT at target concentrations of 100, 500, and 1,000 mg/kg, respectively. The applied voltage gradient across the soil in each test was 1 volt direct current (VDC)/cm for about 500 h. Extent of PCP, DNT, and Lindane destruction in the soil as a result of electrokinetics was ascertained. The study demonstrated that degradation of PCP, DNT, and Lindane occurred during electrokinetics without using any solubilizing or reducing agents in the flushing solution. Results showed that PCP, DNT, and Lindane were degraded by a direct electrochemical reductive process at the electrodes. Contaminant degradation across the soil ranged from 40% to 95%, 28% to 80%, and 26% to 60% for PCP, Lindane, and DNT, respectively. The effectiveness of the electrochemical reduction of the contaminant during electrokinetics depended on the contaminant solubility and soil pH. Overall, this study demonstrated that electrokinetic technology has the potential to remediate chlorinated aromatic and nitroaromatic contaminants in low permeability soils by the direct reductive process.