Electrochemical oxidation of alcohols and carboxylic acids with diamond anodes - A comparison with other advanced oxidation processes

In this work, the conductive-diamond electrochemical oxidation of several short-chain organics (2-propanol, ethanol, butyric acid and chloroacetic acid) has been studied. The results obtained have been compared with those obtained in the oxidation of these compounds with Fenton reagent and with ozone at pH 12. Significant differences have been observed among the three technologies and also between the two ranges of pollutant concentrations studied. However in both cases, the performance of the CDEO overcomes the results obtained by the oxidation with ozone and with Fenton reagent. Likewise, the oxidation with ozone seems to be more effective that the oxidation carried out by the Fenton reagent. Except for ethanol, the nature of the organic does not seem to influence on the performance of the electrochemical technology. However, the efficiencies were found to strongly depend on the concentration of pollutant. In spite of that, the CDEO is able to reduce completely the COD content of the wastes. On the contrary. important concentrations of oxidation-refractory compounds were accumulated during ozonation and Fenton treatments. The mean oxidation state of carbon of the final products obtained by the three technologies is different and this suggests significant differences in the oxidation mechanisms. (C) 2007 Elsevier Ltd. All rights reserved.