Abstract
This work is focused on the combination of classic and modified (ultrasound-assisted) of the Fenton process, for the treatment of water contaminated by an azo dye. The experiments presented herein were carried out on naphthol blue black (NBB), and the obtained results demonstrate a remarkable elimination attaining 99%. The influence of different operating parameters, such as the concentrations of H2O2 and Fe2+, the pH and ultrasound (US) effect, on the dye degradation, was studied as well. The conditions for maximum decolorization efficiency were found to be a pH of 3 and initial concentrations of NBB, Fe2+ and H2O2 of 4.05 x 10(-2) mM, 0.05 mM and 2 x 10(-3) mM, respectively, after 60 min of reaction time with a stirring rate of 300 rpm. It was found that under these conditions, a decolorization of NBB of 99% is achieved. In addition, the combination of low-frequency ultrasound (40 kHz and 30 W) with the Fenton process (US/H2O2/Fe2+) gave a better decolorization efficiency compared to H2O2/Fe2+ alone. Where the decolorization efficiency increased from 63% to 95% at 5 min of reaction time. This result may be caused by ultrasonic irradiation, which greatly increases the rate of H2O2 production. In view of these results, the sono-Fenton process can be used for the oxidation of NBB to reduce reaction time and chemical costs.