Aqueous Oxytetracycline and Norfloxacin Sonocatalytic Degradation in the Presence of Peroxydisulfate with Multilayer Sheet-Like Zinc Oxide

Multilayer ZnO sheet-like flakes were synthesized by a simple method of precipitation and characterized by the techniques of X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The findings are proven that the SEM images show the overall morphology of a single sheet-like ZnO nanostructure made from uniformly thick nano-sheets. In an aqueous environment, the acoustic ability of the prepared material was assessed using ultrasound (US) radiation to degrade oxytetracycline (OTC) and norfloxacin (NF). To increase the degradation efficiency, a US/ZnO/peroxodisulfate system was developed by introducing ammonium persulfate ((NH 4 ) 2 S 2 O 8 ) and sodium persulfate (Na 2 S 2 O 8 ), exhibiting excellent synergistic effects. Result show the decomposition efficiency for NF removal with Na 2 S 2 O 8 (64%) appeared to be slightly better than with (NH 4 ) 2 S 2 O 8 (56%). By contrast, the ultrasonic catalytic efficiency of Na 2 S 2 O 8 (98%) was slightly better than that of (NH 4 ) 2 S 2 O 8 (94%) for OTC removal. The addition of scavengers to the US/ZnO/peroxodisulfate system through the NF and OTC results in the largest effect of holes. The degradation is considered to be often caused by holes. In this system, the Na 2 S 2 O 8 can have two roles to increase the rate of degradation: (1) The SO 4 − formed by Na 2 S 2 O 8 under ultrasonic irradiation directly degraded to norfloxacin on ZnO surface; and (2) S 2 O 8 2- behaved as an electron acceptor, inhibiting recombination of electron hole pairs, enabling the development of more ·OH. Therefore, the synergistic effect significantly increases US/ZnO/peroxodisulfate sonocatalytic activity (Hu, S.B., et al., 2017. Aqueous norfloxacin sonocatalytic degradation with multilayer flower-like ZnO in the presence of peroxydisulfate. Ultrasonics Sonochemistry, 38 (1), pp.446–454).