Removal of phenanthrene from soil by additive-enhanced electrokinetics

Abstract

Removal of hydrophobic organic contaminants (HOCs) using an additive-enhanced electrokinetic method wasstudied in a model system. Kaolinite and phenanthrene wereselected as a model clay soil and a representative HOf, respec-tively. Three difrerent chemically-synthesized surfnctants alongwith two difrerent biosurfactants were used to remove phenan-threne. Hydrogen peroxide was also used to degrade phenan-threne. Electrokinetic (EK) column experiments were performedusing these additives. When no additive was used, a removal effi-ciency of phenanthrene was 4.23% after 2 weeks. When surfac-tants were added in the EK system, the removal efficiencies after2 weeks were as follows: APG 11.1%, Brij30 6.31%, SDS 9.97%, MEL 16.2% and BS-UC 17.4%. Among surfactants, biosurfac-tants 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 chem-ical treatment by hydrogen peroxide incorporated with EK method to remove phennnthrene from clay soil.