Removal of phenanthrene from soil by additive-enhanced electrokinetics

Removal of hydrophobic organic contaminants (HOCs) using an additive-enhanced electrokinetic method was studied in a model system. Kaolinite and phenanthrene were selected as a model clay soil and a representative HOC, respectively. Three different chemically-synthesized surfactants along with two different biosurfactants were used to remove phenanthrene. Hydrogen peroxide was also used to degrade phenanthrene. Electrokinetic (EK) column experiments were performed using these additives. When no additive was used, a removal efficiency of phenanthrene was 4.23% after 2 weeks. When surfactants were added in the EK system, the removal efficiencies after 2 weeks were as follows: APG 11.1%, Brij 30 6.31%, SDS 9.97%, MEL 16.2% and BS-UC 17.4%. Among surfactants, biosurfactants had higher removal efficiencies than chemically-synthesized surfactants. When hydrogen peroxide was used, 54.7% of initial amount was removed at a current of 5 mA for 2 weeks. Even a higher removal efficiency was achieved (84.2%) at 10 mA within 1 week. These results suggest a detailed future study on the chemical treatment by hydrogen peroxide incorporated with EK method to remove phenanthrene from clay soil.