Preparation, characterization and photocatalytic degradation of methylene blue by Fe^3+ doped TiO2 supported on natural zeolite using response surface methodology

The photocatalytic degradation of methylene blue was investigated with TiO2 and Fe2O3 nanoparticles supported on natural zeolite. The synthesized photocatalyst was characterized by XRD, XRF, FT-IR, EDX, FE-SEM, and BET analyses. The results of XRD, FT-IR, and EDX confirmed the successful loading of Fe^3+ doped TiO2 nanoparticles on natural zeolite. Further, the FE-SEM results confirmed the deposition of TiO2/Fe2O3 on the zeolite, with the approximate particle size being 52.3 nm. According to the XRF results, the synthesized nanoparticles had Fe^3+/TiO2 molar ratios of 0.06 in the synthesized photocatalyst. Based on BET analysis, the surface area of TiO2/Fe^3+/natural zeolite was about 112.69 m^2/g. The effects of operational factors such as pH (6-10), dye concentration (25-75 mg/L) and H2O2 concentration (10-40 mg/L) were considered and optimized via response surface methodology utilizing Box-Behnken design. The optimization results indicated that the maximum percentage of degradation was achieved at a dye concentration of 25 mg/L, initial pH of 10, and H2O2 concentration of 40 mg/L with a 90 min irradiation time and a 1 g/l photocatalyst concentration. The dye degradation efficiency reached 92% under this optimum condition.