The electrochemical behavior of synthetic boron-doped diamond thin-film electrode ~BDD! has been studied in acid media containing 4-chlorophenol 4-CP by cyclic voltammetry, chronoamperometry, and bulk electrolysis. The results have shown that in the potential region of supporting electrolyte stability 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 potentials, in the region of electrolyte decomposition, complex oxidation reactions can take place involving electrogenerated hydroxyl radicals, leading to the complete incineration of 4-chlorophenol. Electrode fouling is inhibited under these conditions. The experimental results have been also compared with a theoretical model. This model is based on the assumption that the rate of the anodic oxidation of 4-CP is a fast reaction. Finally, high-pressure liquid chromatographic analyses revealed that the main intermediate products of 4-CP oxidation were 1,4-benzoquinone, maleic acid, formic acid, and oxalic acid.
Oxidation of 4-Chlorophenol at Boron-Doped Diamond electrodes for Wastewater Treatment
PANIZZA, MARCO;CERISOLA, GIACOMO;
2001-01-01
Abstract
The electrochemical behavior of synthetic boron-doped diamond thin-film electrode ~BDD! has been studied in acid media containing 4-chlorophenol 4-CP by cyclic voltammetry, chronoamperometry, and bulk electrolysis. The results have shown that in the potential region of supporting electrolyte stability 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 potentials, in the region of electrolyte decomposition, complex oxidation reactions can take place involving electrogenerated hydroxyl radicals, leading to the complete incineration of 4-chlorophenol. Electrode fouling is inhibited under these conditions. The experimental results have been also compared with a theoretical model. This model is based on the assumption that the rate of the anodic oxidation of 4-CP is a fast reaction. Finally, high-pressure liquid chromatographic analyses revealed that the main intermediate products of 4-CP oxidation were 1,4-benzoquinone, maleic acid, formic acid, and oxalic acid.
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