Electroosomotic Removal of Gasoline Hydrocarbons and TCE From Clay

This laboratory study examines the application of electroosmosis (EO) for removal of hydrocarbons from clay. EO mobilization is conducted in 7.62‐cm inside diameter (id) glass columns containing 30.48 cm of clay and tap water electrolyte. Iron electrodes are used to impress a 0.4‐volt/cm DC electrical gradient. Destructive sampling of columns following various periods of EO treatment results in breakthrough curves describing relative hydrocarbon contaminant mobilization. EO flushing of dissolved organic chemicals in fine‐grained soils can be predicted using traditional contaminant‐transport equations, which incorporate advection, dispersion, and adsorption. Chemicals with relatively high water solubilities and low distribution coefficients (i.e., benzene, toluene, trichloroethylene (TCE), and m‐xylene) are easily removed from Kaolin by EO. Chemicals with a low water solubility and high distribution coefficient (i.e., hexane and isooctane) are transported from the clay at a slower rate. EO has the potential to remove hydrocarbons from fine‐grained soils. Additional laboratory‐ and bench‐scale studies will be needed before the feasibility of the technique in field applications can be determined.