Electrochemical Treatment of Dye Solution by Oxalate Catalyzed Photoelectro-Fenton Process Using a Carbon Nanotube-PTFE Cathode: Optimization by Central Composite Design

Decolorization of C. I. Basic Blue 3 (BB3) by oxalate catalyzed photoelectro-Fenton process based on carbon nanotube-polytetrafluoroethylene (CNT-PTFE) electrode as cathode under visible light was studied. A comparison of electro-Fenton, photoelectro-Fenton, and photoelectro-Fenton/oxalate processes for decolorization of the solution containing BB3 has been performed. The results showed that color removal follows the decreasing order: photoelectro-Fenton/oxalate > photoelectro-Fenton > electro-Fenton. Response surface methodology (RSM) was employed to assess individual and interactive effects of the four main independent parameters on the decolorization efficiency. A central composite design (CCD) was employed for optimization of photoelectro-Fenton/oxalate treatment of BB3. The analysis of variance (ANOVA) showed a high coefficient of determination value (R-2=0.958) and satisfactory prediction second-order regression. This study clearly showed that RSM was one of the suitable methods to optimize the operating conditions.