Degradations of model compounds representing some phenolics in olive mill wastewater via electro-Fenton and photoelectro-Fenton treatments.

The electrochemical oxidation of vanillic acid, o-coumaric acid and protocatechuic acid, three representative toxic phenolics in olive mill wastewater, was studied using carbon felt cathode in the electro-Fenton system. Results obtained, in the presence or absence of UV support, were compared throughout the degradation processes up to mineralization. It was demonstrated that all three phenolic compounds reacted completely with hydroxyl radicals and degraded efficiently. It was shown in the photoelectro-Fenton process that the degradation and mineralization efficiency of the phenolic compounds were enhanced by the effect of UV light, especially at the later stages of the degradation processes.