Synthesis and characterization of Fe₂O₃ doped ZnO supported on clinoptilolite for photocatalytic degradation of metronidazole

ABSTRACT

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 0.23 cm³/g, respectively. According to the UV–VIS DRS results, the band gap energy of the photocatalyst was measured as 3.38 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 (1–100 mg/l), irradiation time (45–180 min), photocatalyst concentration (0.5–2 g/l), and H₂O₂ concentration (25–100 mg/l) were investigated. The optimal values of the factors in degrading 99% of the contaminant were as follows: irradiation time = 90 min, photocatalyst concentration = 1 g/l, pH = 10, H₂O₂ concentration = 40 mg/l, and MNZ concentration = 60 mg/l.

GRAPHICAL ABSTRACT

KEYWORDS:

• Metronidazole degradation
• photocatalytic processes
• ZnO/Fe₂O₃/Clinoptilolite
• contaminated water
• RSM

Acknowledgements

The authors greatly acknowledge Amin Pharmaceutical Company for supplying MNZ antibiotic. We also appreciate the support of Environmental Research Institute and Central Laboratory of University of Isfahan.

Disclosure statement

No potential conflict of interest was reported by the authors.