ENHANCED ELECTROKINETIC REMEDIATION OF HYDROPHOBIC ORGANICS CONTAMINATED SOILS BY THE COMBINATION OF NON-IONIC AND IONIC SURFACTANTS

Abstract

ABSTRACT Electrokinetic soil remediation is a promising technology for the removal of organic contaminants in soil. Its efficiency can be greatly improved by using surfactants as flushing solution due to the low solubility in water of most of organic contaminants. In this study, ionic (sodium dodecyl sulfate, SDS) and non-ionic surfactants (Tween 80 and Triton X100) were selected for the enhanced electroremediation of soil contaminated with aliphatic hydrocarbons and PAHs. The effectivity of surfactants for the removal of n-hexadecane or anthracene was SDS > Tween 80 > Triton X100. The simultaneous use of SDS in the catholyte and Tween 80 in the anolyte improved the removal of n-hexadecane (69%) and anthracene (59%) by electro-osmosis towards the cathode chamber. Unfortunately, when the same operating conditions were applied to a soil specimen contaminated with the two organics, the removal slightly dropped to 67.7% for n-hexadecane and 54.7% for anthracene. These results were interpreted in terms of concentration and interaction of contaminants. The soil specimen contained more contaminants and their interaction resulted in lower solubility even with the simultaneous use of the two surfactants. Overall, the combination of surfactants seemed to be a good approach for the removal of contaminated soils with hydrophobic organics.