Assessment of IrO2-Ta2O5|Ti electrodes for the electrokinetic treatment of hydrocarbon-contaminated soil using different electrode arrays

Abstract In recent years, physicochemical processes such as electrokinetic treatment (EKT) have gained acceptance as suitable alternatives to restore hydrocarbon (HC)-contaminated sites. EKT entails relatively short times and high removal efficiencies, usually being applied in heterogeneous soils with low permeability. In this work, 1D (one-dimensional) and 2D (two-dimensional) configurations have been tested employing Ti cathodes and anodes, as well as purpose-made IrO 2 -Ta 2 O 5 |Ti as dimensionally-stable anodes (DSA ® ). After EKT and from GC-MS analysis of fat and oil content, it has been found that the radial 2D array with one central Ti cathode and six IrO 2 -Ta 2 O 5 |Ti anodes performed the best removal efficiency of hydrocarbons. The removal efficiencies of using modified electrodes with a configuration of circular 2D electrodes had double the removal efficiency (58%) over the use of a configuration of face-to- face 1D array (21%) with the IrO 2 -Ta 2 O 5 |Ti anode and Ti cathode. Finally, the superficial morphology of IrO 2 -Ta 2 O 5 |Ti anode and Ti cathode were not affected by EKT, which was demonstrated with the same appearance before and after EKT in the micrographs obtained by SEM.