Removal of Hexachlorobenzene from Kaolin by Electrokinetics Coupled with Cu/Fe PRB

This study deals with the remediation of clayed soils contaminated with hydrophobic organic compounds (HOCs) by using electrokinetics (EK) coupled with a permeable reactive barrier (PRB) technique. Hexachlorobenzene (HCB) and kaolin were selected as the typical HOCs and clay, respectively, and microscale Cu/Fe particles were synthesized as the functional materials of PRB. Furthermore, Triton X-100 was used as the solubility-enhanced agent to promote the movement and removal of contaminants. Four bench-scale EK tests were conducted with or without Cu/Fe PRB. The results reveal that coupling EK with Cu/Fe PRB greatly promoted the overall removal of HCB from soil, compared with EK alone. Other than the electroosmotic flow, the adsorption/reductive degradation by Cu/Fe PRB may also be responsible for the HCB removal (over 82% of HCB passing by the PRB was removed). Our investigation suggests that the integration of EK and Cu/Fe PRB is of great promise to promote the application of EK technique in the remediation of HOC-contaminated soils.