Synthesis of ZnFe2O4@Uio-66 nanocomposite for the photocatalytic degradation of metronidazole antibiotic under visible light irradiation

In this study, the application of ZnFe2O4, Uio-66 nanoparticles and ZnFe2O4@Uio-66 photocatalytic nanocomposites, with different ratios of each component was synthesized and applied for the photocatalytic degradation of metronidazole (MNZ) antibiotic. The samples were characterized with (FTIR), (XRD), (SEM), (DLS), (VSM), and UV-Vis spectroscopy. The photocatalytic process was performed under visible light in an aqueous solution. The optical studies revealed that the addition of ZnFe2O4 nanoparticles could stimulate the activation wavelength of the nanocomposite, effectively shifting it to the visible light region, and correspondingly reduce the bandgap. To evaluate the ability of ZnFe2O4@Uio-66 magnetic nanocatalyst to degrade metronidazole, effective parameters such as the initial concentration of MNZ in aqueous solution(10–90 mg/L), pH(2–10), the illumination and darkness time and photocatalyst dosage(0.01–0.05 g) were investigated and optimized. It was observed that when ZnFe2O4 concentration was twice that of Uio-66, the degradation efficiency increased. The optimum degradation conditions, at which 93.7% degradation efficiency was achieved, were determined at 120 min brightness, 40 min darkness, pH = 8, initial concentration of 10 ppm, and photocatalyst content of 0.03 g. Based on the results of photocatalytic degradation kinetics, all the samples followed the Langmuir-Hinshelwood pseudo-first-order kinetics model.