Application of response surface methodology for optimization of peroxi-coagulation of textile dye solution using carbon nanotube-PTFE cathode

The decolorization of C.I. Basic Yellow 2 (BY2) by peroxi-coagulation process based on carbon nanotube-PTFE electrode as cathode was studied in a batch reactor. Response surface methodology (RSM) was employed to assess individual and interactive effects of the four main independent parameters (electrolysis time, initial pH, applied current and initial concentration of the dye solution) on the decolorization efficiency. A central composite design (CCD) was employed for the optimization of peroxi-coagulation treatment of BY2. A second-order empirical relationship between the response and independent variables was derived. Analysis of variance (ANOVA) showed a high coefficient of determination value (R² = 0.949). Maximum decolorization efficiency was predicted and experimentally validated. The optimum electrolysis time, initial pH, applied current and initial dye concentration were found to be 16 min, 3, 200 mA and 15 mg l^-1, respectively. Under the optimum conditions established, high decolorization (>95%) was experimentally obtained for BY2. This study clearly showed that response surface methodology was one of the suitable methods to optimize the operating conditions. Graphical response surface and contour plots were used to locate the optimum point.