Removal of the pesticides from soil using electrokinetic method

This study was designed to test the capability of electrokinetic technology to remediate the soils contaminated with pesticides and metals. A non-polluted soil sample was collected from a forest area, not affected by the human activity. The soil sample was characterized for physical and chemical properties and then spiked with Cu and imidacloprid, two main components of pesticides commonly used in agricultural soils. Soil sample was composed of 9% gravel, 80% sand, 11% silt and clay. The moisture content of soil was 5% and the specific gravity was 2.36. The initial contaminant concentrations were 298 mg/kg of Cu and 3.75 mg/kg of Imidacloprid. A column extraction test was performed to investigate the environmental effects associated with the mobility of the contaminants in the soil. The result of this test showed that copper was partially mobilized by water. No significant mobilization was detected for imidacloprid. The electrokinetic treatment at constant electric gradient (1 DCV/cm) using DI water as processing fluid was able to mobilize and transport the Cu toward the anode and Imidacloprid toward the cathode. However, the net removal of the Cu and Imidacloprid from soil was low. The limited removal efficiency of the contaminants was associated to the short treatment time (1 week) and the premature precipitation and adsorption of the contaminants to the soil particles due to the local physicochemical conditions (mainly pH) in the soil close to the electrodes. This study suggested that electrokinetics can be used for the effective removal of pesticides and metals from soil under controlled physicochemical soil conditions.