Photocatalytically-assisted electrochemical degradationof p-aminophenol in aqueous solutionsusing zeolite-supported TiO_2 catalyst

摘要

This paper reports the results of an investigation into enhancement of the electrochemical oxida-tion of p-aminophenol (4-AP) in an aqueous solution with a boron-doped diamond (BDD) electrode, assisted by photocatalysis using a zeolite-supported TiO_2 (Z-TiO_2) catalyst. The BDD electrode was characterised in 0.1 M Na_2SO_4-supporting electrolyte and the presence of 4-AP by open-circuit potential behaviour (OCP) and cyclic voltammetry (CV). The electrode behaviour was investigated in the dark and following UV irradiation and in the absence/presence of the Z-TiO_2catalyst. The electro-oxidation process was carried out using chronoamperometry (CA) and multiple-pulsed amperometry (MPA) at the selected potential under potentiostatic conditions. The electrochemical degradation process of 4-AP on the BDD electrode was improved by the application of a pulsed potential, which allowed both in-situ electrochemical cleaning of the electrode and indirect oxidation of 4-AP by oxygen evolution. The application of photocatalysis using Z-TiO_2 in the 4-AP electrochemical degradation exhibited an enhanced effect when the anodic potential was set at +1.25 V vs. Ag/AgC1 in the water stability region, close to the oxygen evolution potential.