Photocatalytic treatment of a dye solution using immobilized TiO2 nanoparticles combined with photoelectro-Fenton process: Optimization of operational parameters

Treatment of a dye solution containing C.I. Acid Red 17 (AR17) by photoelectro-Fenton (PEF) combined with photocatalytic process was studied. Carbon nanotube-polytetrafluoroethylene (CNT-PTFE) electrode was used as cathode. The investigated photocatalyst was Millennium PC-500 TiO2 with crystallites mean size of 5–10 nm immobilized on non-woven paper. A comparison of electro-Fenton (EF), UV/TiO2, PEF and PEF/UV/TiO2 processes for decolorization of AR17 solution was performed. Results showed that color removal follows the decreasing order: PEF/UV/TiO2 > PEF > EF > UV/TiO2. Response surface methodology (RSM) was employed to assess individual and interactive effects of the four main independent parameters in PEF/UV/TiO2 process. Analysis of variance (ANOVA) showed a high coefficient of determination value (R2 = 0.978) and satisfactory prediction second-order regression. The optimum initial amount of Fe(III), initial dye concentration, reaction time and applied current were found to be 0.2 mM, 15 mg/L, 36 min and 100 mA, respectively. This study clearly showed that RSM was one of the suitable methods to optimize the operating conditions. Graphical response surface and contour plots were used to locate the optimum point.