Oxidant availability in soil and its effect on HCB removal during electrokinetic Fenton process

Electrokinetic technology in its various forms has already shown its potential as a promising technology for the remediation of organic compounds in soil. Efforts to improve and optimise the process have eventually led to the coupling of electrokinetics with other remediation techniques like chemical oxidation. This paper reports the results of a series of electrokinetic Fenton experiments carried out to investigate the effect of oxidant delivery and availability on contaminant removal and its subsequent impact on the treatment duration. In doing so, we have tried to show that the treatment duration can be considerably reduced by the proper introduction of the oxidants to the soil for a better oxidant availability throughout the soil section. Experiments were conducted at laboratory scale using kaolin spiked with hexachlorobenzene (HCB). Though each experiment resulted in different removal rates, under specific experimental conditions, a maximum of 57% contaminant removal was obtained. However, the oxidation reactions in these experiments did not show any pH dependence in the range 2.9-5. A more uniform and better HCB degradation was possible in a shorter duration by the proper introduction of oxidant into the soil.