Degradation of macrolide antibiotics via sono or photo coupled with Fenton methods in the presence of ZnS quantum dots decorated SnO2 nanosheets

The ZnS quantum dots decorated SnO2 nanosheets were prepared by a hydrothermal synthesis method. The characteristic structure of ZnS QDs/SnO2 nanocomposites was analyzed using several instruments such as X-ray diffraction, transmittance electron microscopy, atomic force microscopy, X-ray photoelectron and UV–vis and photoluminescence spectroscopy. The average diameters of SnO2 nanosheets and ZnS QDs/SnO2 nanocomposites were 12.5 and 3.6 nm, respectively. The merits of sono–photo–Fenton treatment process were investigated using degradation of Roxithromycin. The process involved ultrasound and UV irradiation, and hydrogen peroxide generated in situ. The treatment performance of the US/UV/catalyst process was superior to the constituent processes and synergistic mechanisms in the US/UV/catalyst process were the result of the promotion of hydroxyl radical generation. For the constituent processes, the US/catalyst system showed to the best efficiency with used catalyst compared to the conventional Fenton reaction. It was also observed that the addition of catalyst to the test solution undergoing UV irradiation substantially improved Roxithromycin and clarithromycin degradation. The best experimental conditions for efficient CLA and RXM degradation in the US/UV/catalyst/H2O2 system were pH0 3, hydrogen peroxide concentration of 6 mmol L−1, ZnS QDs/SnO2 nanocomposites dose of 0.3 g L−1 and ultrasonic power of 75 W. The antibacterial experiment was investigated under visible light illumination and the ZnS QDs/SnO2 nanocomposite showed good efficiency as antibacterial.