Application of electro-Fenton process as alternative for degradation of Novacron Blue dye

The electrochemical removal of a synthetic solution containing 190 mg L-1 of Novacron Blue (NB) dye has been studied by electro-Fenton process using a carbon felt gas-diffusion O-2 cathode to produce in situ hydrogen peroxide by oxygen reduction. The effect of operating conditions (Fe2+ concentration, applied current and pH solution on the efficiency of the process) was investigated. Results clearly showed that NB and their products may be effectively degraded by the (OH)-O-. radicals produced by the reaction between the Fe2+ ions and the in situ electrogenerated H2O2 at carbon felt gas-diffusion O-2 cathode. After 4 h of electrolysis, chemical oxygen demand (COD) removal was only 34% when no ferrous ions were added to the solutions, while the presence of ferrous ion greatly improved COD removal to more than 90%, depending on operating conditions. Spectrophotometric analysis indicated that the discoloration of the solution occurs in all operating conditions, while gas chromatographic / mass spectrometry analysis confirmed the degradation of NB dye via identification of the principal intermediates formed. (C) 2014 Elsevier Ltd. All rights reserved.