Effect of Polarity Reversal on Hexachlorobenzene Removal during Electrokinetic Fenton Process

Experimental evidence shows that the electrokinetic Fenton process is very effective for cleaning soil contaminated with organic compounds, especially hydrophobic and persistent organic pollutants. Despite the technological progress in recent years, there are still several performance-related issues to be addressed, such as its implication on the final soil quality and different oxidant delivery schemes. This paper reports the results of a series of experiments carried out to explore the possibilities of using polarity reversal as an enhancement during electrokinetic Fenton treatment of soil contaminated with persistent organic pollutants. Laboratory-scale experiments were conducted with kaolin and hexachlorobenzene (HCB) as the model soil and contaminant, respectively. Experiments were performed both with and without added iron (Fe). Reversing the polarity of electrodes after a period during the experiments was found to be effective in aiding the reachability of the oxidant to the soil specimen in a shorter duration. An overall HCB removal of 10% in 10 days was increased to 33% with one polarity reversal during the treatment. However, its use with different oxidant delivery methods is to be considered carefully, because it was observed that the addition of hydrogen peroxide (${\mathrm{H}}_2{\mathrm{O}}_2$ ) from the anode chamber was crucial for HCB degradation to occur.