Dual-electrode oxidation used for aniline degradation in aqueous electrolyte

Abstract

The electrochemical degradation of aniline in aqueous electrolyte has been studied by dual-electrode oxidation process using Ti/SnO2-Sb2O5 for anodic oxidation and graphite cathode to produce H2O2 in situ. The linear voltammograms were employed to obtain reasonable anodic and cathodic potential values for the purpose of restraining side reactions. The influence of Fe2+ on aniline degradation was investigated under potentiostatic condition with a three-electrode system. It was found that an anodic potential range of 2.0 +/- 0.1 V and a cathodic potential of -0.65 V could favor anodic oxidation and H2O2 generation. Anodic oxidation was accounted for aniline degradation in the absence of Fe2+, while in the presence of Fe2+ both electro-Fenton oxidation and anodic oxidation (dual-electrode oxidation) could degradate aniline effectively. When cathodic potential values were -0.65 and -0.80 V, the optimum Fe2+ concentration were 0.50 and 0.30 mM, respectively. 77.5% COD removal and 70.4% TOC removal with a current efficiency (CE) of 96-100% were achieved under the optimum conditions. This work indicates that dual-electrode oxidation process characterized by a high CE is feasible for the degradation of organic compounds.