The degradation of 100 cm(3) of a solution with 0.167 mmol dm(-3) eactive Yellow 160 (RY160) azo dye in sulfate medium at pH 3.0 has been comparatively studied by anodic oxidation with electrogenerated H2O2 (AO-H2O2), electro-Fenton (EF) and UVA photoelectro-Fenton (PEF). Trials were carried out with a stirred tank reactor equipped with a boron-doped diamond (BDD) anode and an air-diffusion cathode for H2O2 production, upon addition of 0.50 mmol dm(-3)Fe(2+) as catalyst in EF and PEF. The solution was slowly decolorized by AO-H2O2 because of the low rate of reaction of the azo dye and its colored products with hydroxyl radicals generated at the BDD anode from water oxidation. The color loss was enhanced in EF by the larger oxidation ability of hydroxyl radicals produced in the bulk from Fenton's reaction between added Fe2+ and generated H2O2, whereas the solution was more rapidly decolorized by PEF owing to the additional generation of hydroxyl radicals from the photolysis of Fe(III)-hydroxy complexes by UVA light. The relative mineralization ability of the processes also increased in the sequence AO-H2O2

Keywords:Anodic oxidation;Electro-Fenton;Photoelectro-Fenton;Reactive Yellow 160;Water treatment