Electrochemical oxidation of phenol for waste water treatment

The electrochemical oxidation of phenol for waste treatment applications was investigated on lead dioxide packed-bed anodes. The electrolytic cell was operated in both batch and continuous modes with feed streams up to 1100 mg/l phenol dissolved in aqueous solutions of Na₂SO₄ and H₂SO₄ or NaOH. Electrodeposited lead dioxide was found to be a better anode for phenol oxidation, than the lead dioxide obtained by anodizing lead shot. Results showed that all the phenol in solution could be readily oxidized but complete total organic carbon (T.O.C.) removal was more difficult. Rates of phenol oxidation were similar in divided and undivided cells. The oxidation of phenol was favoured by an acidic pH, but an alkaline pH improved the further oxidation of intermediate products. In divided cells, an anionic membrane, which allowed migration of hydroxyl ions, proved to be superior than a cationic membrane for T.O.C. removal. The percent of phenol oxidized increased with increasing current density, and decreased as initial phenol concentration, electrolyte flow rate, and anode particle size were increased. Comparisons of the experimental results with a mass transfer model are presented for the batch experiments, and a simplified model is proposed to interpret the results from continuous experiments in terms of relative mass transfer and electrochemical reaction resistances.Applied Science, Faculty ofChemical and Biological Engineering, Department ofGraduat