Studies on electrochemical detoxification of trichloroethene (TCE) on Ti/IrO2–Ta2O5 electrode from aqueous solution

Abstract

Anodic oxidation of trichloroethene (TCE), a toxic chlorinated water contaminant, is carried out using Ti/IrO2–Ta2O5 electrode. The redox behaviour of TCE molecule, fouling of electrodes and generation of oxygen was studied by cyclic voltammetry. The studies on cyclic voltammetry reveals that the TCE oxidation takes place directly on electrode surface at the potential region above 0.3 V vs. SCE by direct electron transformation and oxygen evolution from anode. The effect of the electrolyte, pH of the aqueous medium and applied current density on the mineralization behaviour of TCE is also investigated. The degradation of TCE is monitored in terms of TOC and TCE concentration with electrolysis time and corresponding chloride evolution. The complete mineralization of TCE is achieved using Na2SO4 as supporting electrolyte. Conversely, the mineralization of the TCE molecule was observed to be poor because of the electrode fouling in the presence of NaNO3. The dechlorination of TCE is found to increase with electrolysis time and the complete dechlorination is observed at all Iappl studied. The kinetics of TCE degradation was found to follow pseudo-first order reaction whose rate constant was calculated to be 0.0081 cm s1 at Iappl value of 13.39 mA cm2. The performance of Ti/IrO2–Ta2O5 anode was proved to be better compared to Pt under similar experimental conditions.