Enhancing electrokinetic soil flushing with air stripping for the treatment of soil polluted with phenol and o-chlorophenol

Abstract

This paper describes the treatment of soil spiked with a mixture of phenol and o-chlorophenol in a bench-scale plant combining Electrokinetic Soil Flushing with Air Stripping (EKSF-AS). Results demonstrate that this combination can be a good alternative for the remediation of soils, although many initially unexpected results were found. Phenol and 2-clorophenol are transported to the cathode wells by dragging with the electroosmotic flow, where they are exhausted by stripping with air. A significant amount of both species reached the anode, where they are transformed by anodic oxidation into a mixture of hydroquinone and benzoquinone, which remains in the anolyte, not being further oxidized, transported to the cathode or dragged by the electro-osmotic (EO) flux (more than 58 and 66% of the initial pollution was transported from soil to anolyte well, respectively at 0.75 and 1.50 V cm−1). Injected pressurized air can haul an important part of the pollution (more than 25%) and nearly 95% of the pollution contained in the raw soil is depleted after 14 days of treatment.