Oxidation of 4-chlorophenol at boron-doped diamond electrode for wastewater treatment

The electrochemical behavior of synthetic boron-doped diamond thin-film ele ctrode (BDD) has been studied in acid media containing 4-chlorophenol (4-CP ) by cyclic voltammetry, chronoamperometry, and bulk electrolysis. The resu lts have shown that in the potential region of supporting electrolyte stabi lity occur reactions involving the oxidation of 4-CP to phenoxy radical and 1,4-benzoquinone. Polymeric materials, which result in electrode fouling, are also formed in this potential region. Electrolysis at high anodic poten tials, in the region of electrolyte decomposition, complex oxidation reacti ons can take place involving electrogenerated hydroxyl radicals, leading to the complete incineration of 4-chlorophenol. Electrode fouling is inhibite d under these conditions. The experimental results have been also compared with a theoretical model. This model is based on the assumption that the ra te of the anodic oxidation of 4-CP is a fast reaction. Finally, high-pressu re liquid chromatographic analyses revealed that the main intermediate prod ucts of 4-CP oxidation were 1,4-benzoquinone, maleic acid, formic acid, and oxalic acid. (C) 2001 The Electrochemical Society. [DOI: 10.1149/1.1362545 ] All rights reserved.