The removal of diesel from a sandy soil column was conducted bysurfactant enhanced electrokinetic remediation process to study theeffects of the electric field direction on the diesel removalefficiency. Anionic surfactant SDS (sodium dodecyl sulfate) was fedto one of the electrode chambers driven by electrokinetics and/or apump. When an electric current was applied while SDS was fed to anodechamber at a constant rate by pump, an effluent flowrate higher thanthe feeding rate was obtained at cathode side because the directionsof electroosmosis and pumped convective flow were identical.Meanwhile, when SDS was fed to cathode chamber by pump in thepresence of an electric current, a lowered effluent flowrate wasobtained, where the directions of electrosmosis and pumped flow wereopposite. In this case, however, the diesel removal rate and totalrecovered amount of diesel were substantially increased compared tothe case that SDS was fed to anode side. Results implied in SDStransport through the soil column that the electrophoretic transportof SDS anion towards anode was dominant over the retardation of SDStransport by the electroosmosis flowing towards cathode. The dieselmobilization would be achieved by solubilization of diesel componentsinto SDS micelles and thus by transporting of SDS-diesel complexestogether convectively and electrophoretically towards anode side.
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