Anodic Degradation of 2-Chlorophenol by Carbon Black Diamond and Activated Carbon Composite Electrodes

A carbon black diamond composite electrode with 20% carbon black (20CBD) and activated carbon composite (ACC) electrode were prepared and used as anodes for 2-chlorophenol electro-oxidation. The electro-oxidation behaviors of 200 mg/L 2-chlorophenol on 20CBD and ACC anodes were investigated by cyclic voltammetry in aqueous solutions of 0.5 M H₂SO₄ (pH 0.55) and 0.25 M Na₂SO₄ (pH 7). Results indicated that the 20CBD and ACC electrodes are more active at low pH than at high pH and that no oxidation peak appears on the ACC electrode. The performance of the 20CBD and ACC electrodes during degradation of 200 mg/L 2-chlorophenol was investigated in an aqueous solution of pH 3 with 0.25 M Na₂SO₄ as the supporting electrolyte and applied current density of 30 mA/cm². Results showed that the 20CBD electrode produced the best degradation rate, COD removal efficiency, and current efficiency. The degradation efficiencies of the 20CBD and ACC electrodes after 6 h were 96% and 82.5%, respectively. The effects of solution pH, current density, and supporting electrolyte on the performance of the 20CBD were further investigated, and results showed that higher degradation rates are obtained at lower pH and with Na₂SO₄ as the supporting electrolyte. Removal efficiency also increased with increasing current density.