Oxytetracycline photodegradation by transition metals doped ZnO nanorods

In recent decades, pollution increases in water resources endanger human life and other living organisms. Researchers have applied different methods to eliminate water contaminants. Photocatalytic is one ofaz these methods that have been used widely for wastewater treatment. In this study, a series of Mn, Fe, Co, Ni, and Cu-doped ZnO nanorods were applied as visible-light-activated catalysts for oxytetracycline (OTC) degradation. Characterization of the nanorods was performed using XRD, FE-SEM, UV-Vis, and PL techniques. The results demonstrate that the photocatalytic activity of the samples highly depends on the morphology, size, and band gap energy. The UV–Vis spectroscopy indicates that Fe doping has reduced the band gap energy to 2.91 eV. The variation of the band gap permits the absorption of low-energy photons and the excitation of valence band electrons. The photoluminescence spectra reveal that doping has an effective role in inhibiting the recombination of electron/hole pairs during the photocatalytic process. The Mn-doped sample exhibits significantly increased photocatalytic activity and greater degradation rate constant (k) in comparison with the pure ZnO.