Anodic oxidation of 4-chlorophenoxyacetic acid on synthetic boron-doped diamond electrodes

The anodic oxidation of 4-chlorophenoxyacetic acid (4-CPA) on synthetic boron-doped diamond (BDD) thin film electrodes in acid media was investigated, using cyclic voltammetry and bulk electrolysis. The results showed that in the potential region where the supporting electrolyte is stable, reactions occur, resulting in the loss of activity due to electrode fouling. Electrolysis at high anodic potentials in the region of electrolyte decomposition causes complex oxidation reactions that lead to the complete incineration of 4-CPA. There is no indication of electrode fouling under these conditions. The experimental results were also compared with a theoretical model. This model is based on the assumption that the electrochemical oxidation of 4-CPA by electrogenerated hydroxyl radicals is a fast reaction and that the process is diffusion-controlled.