Electrokinetic removal of phenol and petroleum hydrocarbons from contaminated clays

The electrokinetic remediation of two types of clays contaminated with phenol was investigated in the laboratory. Results of two one-dimensional tests with initial phenol concentration of 950 mg/kg are presented in this paper. In addition, soil samples were obtained from Tehran Refinery region to investigate the effects of the clectrokinetic process on clay naturally polluted with petroleum hydrocarbons. Results indicated that phenol removal was dependant on both the cation concentration in the clay matrix and the adsorption capacity of clay for phenol. Phenol removal of 20-60% was achieved in different soils. The results also demonstrated that higher phenol removal efficiency was achieved in clay with lower cation exchange capacity. For samples obtained from Tehran Refinery region, the electrokinetic process could not extract petroleum hydrocarbons from the soil although a 25% (by volume) mixture of methanol-distilled water was used in the anode chamber to conduct in soil the matrix during electroosmotic flow. In addition, adding the methanol to the soil matrix before the test did not increase petroleum hydrocarbon movement toward the cathode significantly.