Performance of Chloride Ions on Electrocatalytic Oxidation Process Using Ti-Nanotubes/PDDA-PbO2 Anode for Phenol Removal

The performance of the electrocatalytic oxidation of phenol on poly(diallyldimethylammonium chloride) (PDDA)-modified PbO2 anodes in the presence of chloride ions was studied. The objective was to elucidate the influence of NaCl dosage, current density, initial phenol concentration, and initial pH on this catalysis process in the presence of Cl-. The results revealed that at low current densities, the presence of Cl- could greatly enhance the current efficiency by electrogenerating active chlorine, and the current density increased, but if competitive adsorption of OH radicals occurred, the removal efficiency did not improve significantly and the current efficiency decreased. This indicated that the pH value had a major impact on phenol, with optimal removal observed at approximately pH 6-7. In both acidic and alkaline solutions outside this optimal pH window, the removal efficiency deteriorated. The modified anode performs well for phenol degradation for a wide range of phenol concentrations under neutral conditions with an appropriate current density (30mA/cm2) and NaCl concentration (0.05M).