Effective removal of reactive blue 222 dye by electrocoagulation and ultrasound-associated electrocoagulation

Abstract

The intention of this study is to find a way out to the dye-based pollution problem, and to contribute scientifically to the decontamination of Reactive Blue 222 (RB222)-originated impurities. Within the scope of the study, classical electrocoagulation (EC) and ultrasound-associated electrocoagulation (USEC) methods were carried into action. Effects of significant process parameters such as initial concentration of dye, current density, pH and operation time on decolorization and degradation of the dye were evaluated. Optimal values of experimental variables were ascertained on the basis of the efficiency of dye removal from the solution bulk. Tests of both EC and USEC processes were resulted in complete decolorization having removal efficiency of approximately 100% particularly even at low current densities and high dye concentrations. A significant reduction in the operation time by applying the USEC compared to ordinary EC process was noted, especially at the beginning term of decolorization process. 50 ppm (pH 5.0) dyestuff solution exposed to a current density of 2 mA/cm2, after only 4 minutes of operation, achieved color removal of 58% with the electrocoagulation process and 74% with the ultrasonic enhanced electrocoagulation process. It was also observed that the 15-min operation time was sufficient for dyestuff removal with 99% efficiency for both of the processes. These data clearly reveal that ultrasound process as an accelerating element for electrocoagulation can be included in the electrolytic environment early in the process.