Sonoelectrochemical oxidation for decolorization of Reactive Red 195

The decolorization and degradation of Reactive Red 195 (RR 195) is studied using sonoelectrochemical and electrochemical oxidation. Sonoelectrochemical oxidation was found to be more efficient than electrochemical oxidation. The efficiency of decolorization was found to be 91% and 99% in the case of electrochemical and sonoelectrochemical process, respectively. The effect of different supporting electrolytes and ultrasonic power on decolorization and COD removal has been studied. The decolorization was found to be maximum in the KCl and NaCl as electrolytes. The color removal decreased with increasing ultrasonic power. Response surface methodology was used to assess optimal condition for decolorization and COD removal of RR 195. A Central Composite Design in five most important operating variables; current density, electrolyte concentration, dye concentration, time and sonication power was employed for experimental design and optimization of results. The significance of independent variables and their interactions were tested by means of the analysis of variance with 95% confidence limits. There was good agreement between the experimental and predicated values. Sonoelectrochemical degradation was found to be efficient in decolorizing simulated textile effluent. The results show that ultrasound was significantly enhanced in the electrochemical oxidation. (C) 2011 Elsevier B.V. All rights reserved.