RESUMO
ZnO/Fe2O3/Clinoptilolite photocatalyst was synthesized through sol-gel method. The photocatalyst was characterized by XRD, XRF, EDX, FE-SEM, FT-IR, BET and UV-VIS DRS analyses. According to the XRD, FT-IR, and EDX results, the presence of ZnO and Fe2O3 was confirmed on the clinoptilolite surface. Based on the XRF results, the molar ratio of Fe3+/ZnO in the photocatalyst was obtained as 0.06. The FE-SEM results confirmed stabilization of ZnO/Fe2O3 on the clinoptilolite surface. Based on the BET results, the surface area and pore volume for the photocatalyst were obtained as 291.35 m2/g and 0.23â cm3/g, respectively. According to the UV-VIS DRS results, the band gap energy of the photocatalyst was measured as 3.38â eV. The performance of the synthesized photocatalyst in degrading metronidazole from contaminated water, as one of the most widely used antibiotics in pharmaceutical industries, was evaluated by response surface methodology. Operational factors including pH (4-10), metronidazole concentration (1-100â mg/l), irradiation time (45-180â min), photocatalyst concentration (0.5-2 g/l), and H2O2 concentration (25-100â mg/l) were investigated. The optimal values of the factors in degrading 99% of the contaminant were as follows: irradiation time = 90â min, photocatalyst concentration = 1 g/l, pH = 10, H2O2 concentration = 40â mg/l, and MNZ concentration = 60â mg/l.