Electrochemical degradation of humic acid

The treatment of natural water for drinking water production goes through the degradation of humic substances. In this study, humic acid, extracted from a peat area located at the margins of the Mogi Gua¸cu River at S˜ao Paulo State, Brazil, was used to perform electro-oxidation essays in order to evaluate the possibilities of electrochemical methods in the degradation of humic substances. The working electrodes were dimensionally stable anodes DSA. type with the following compositions: TirIr0.3Ti0.7O2; TirRu0.3Ti0.7O2; and TirIr0.2Ru0.2Ti0.6O2. The electrolyses were performed by using a solution composed of an electrolyte support 0.1 mol ly1 KCl. and 30 mg ly1 of the humic acid. Samples were taken during the electrolyses and analysed by the pH, transmittance, UV-vis spectra and chromatography. The results show that the TirRu0.3Ti0.7O2 electrode presents the best performance considering the elimination of most of the electro-oxidation products after approximately 2 h of electrolysis at 40 mA cmy2.