Dual-electrode oxidation used for aniline degradation in aqueous electrolyte

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.