Enhanced Degradation of the Industrial Textile Dye Disperse Red BG by Electrochemical Process with Different Anodes

Abstract

The in-situ generation of strong oxidants, such as hydroxyl radicals (•OH), persulfates and/or active chlorine species, which react with organics up to conversion into CO2, H2O and inorganic ions, depends on the nature of electrode surface; and their applicability have currently received great attention for the remediation of toxic and biorefractory organic pollutants. Therefore, the effect of four electrocatalytic materials (Boron doped diamond (BDD), PbO2, Ti/Ru0.3Ti0.7O2 and Ti/Pt) for the electro-oxidation of the industrial textile dye DRBG was studied in sulfate and chloride medium in order to understand the role of anodic material as well as the production of oxidants. Results showed that, a higher mineralization rate was obtained using BDD and PbO2 electrodes in sulfate media, due to the generation of •OH and persulfate. However, the mineralization rate of DRBG increased when NaCl was used as supporting electrolyte, reaching almost a total mineralization of the solutions using Ti/Ru0.3Ti0.7O2 and BDD electrodes at short electrolysis time, due to the action of active chlorine species. Aromatic intermediates are formed initially, during the electrochemical oxidation of DRBG, then, short-linear carboxylic acids and inorganic ions were formed until a complete mineralization of initial dye as a consequence of the homogeneous reactions of strong oxidant species.