| Environmental problems of emerging contaminants have been increasingly obvious, developing corresponding detection and treatment technology are of great importance for academic research as well as for practical applications. Fluoroquinolone antibiotics (FQs) is a kind of typical emerging contaminants, having been detected in a variety of water bodies around the world. Herein, fluorescence detection methods of norfloxacin (NOR) and ciprofloxacin (CIP) were firstly established in the thesis. Novel photocatalysts of C/Fe-BiVO4and C/Fe-Bi2WO6were synthesized, with effective response to visible lights and Fenton reaction. The wastewater treatment method and process of those two FQs were established as well. In the end, the thesis discussed the photocatalysis mechanism.First, the fluorescence quenching method was used to test norfloxacin in water. With neutral red acted, as probe molecules, hydroxypropyl-beta-cyclodextrin (HP-β-CD) formed inclusion compound and thus fluorescence intensity of neutral red has greatly increased. On the other hand, addition of norfloxacin induced to the fluorescence quenching of NR-HP-β-CD system. A new detection method, with fluorescence quenching technique, of norfloxacin was invented accordingly. Under the optimal conditions, fluorescence intensity of the system presented good linear relationship with the concentration of NOR in the range of0.02～0.4mg/L, with correlation coefficient R20.9993, and the detection limit reached6.1μg/L (S/N=3). At the same time, the interferences from common metal ions and some organic matters were analyized. The recovery test and content determination of NOR were also carried out in environmental water samples.Second, the fluorescence probe method was used to test ciprofloxacin in water. L-cysteine coated ZnS microspheres was synthesized by hydrothermal method and a new approach of determining CIP is created based on fluorescent probe method of L-cysteine coated ZnS microspheres. Under the optimal comditions, fluorescence intensity of the system presented a good linear relationship with the concentration of CIP in the range of0.10～870μg·L-1, with the correlation coefficient R20.9997, and the detection limit reached0.06μg·L-1(S/N=3). The interferences from common metal ions and some organic matter were analyized as former. The recovery test and content determination of CIP were also carried out in environmental water samples.Moreover, the C/Fe-BiVO4photocatalyst was prepared by a two-step approach, involving resin carbonization and hydrothermal reaction process. Meantime, the preparation processes were optimized, which obtainted a set of best preparation parameters: the temperature of hydrothermal reaction is180℃, time of hydrothermal reaction is24h, pH value of hydrothermal precursors is3, calcining temperature is500℃, calcination velocity is10℃/min, calcining time is2h. The structure and chemical properties of the catalysts were characterized by EDX, XPS, XRD, SEM, BET, DRS, FT-IR, PL and Zeta potential analysis technology. Results showed the synthesized C/Fe-BiVO4catalysts have slice-shape nanostructures and good crystal structure, specific surface area17.76m2·g-1. The samples have macroporous and mesoporous structure. The catalyst has good visible light absorption ability. C/Fe-BiVO4acted and H2O2, as photocatalyst and oxidant respectively, performed good degradation effect for CIP. The degradation process complied with Landmuir-Hinshelwood (L-H) pseudo-first-order kinetics model, with the reaction kinetic constants0.1061min-1.Besides, the C/Fe-Bi2WO6photocatalyst was prepared by a two-step method, involving resin carbonization and hydrothermal reaction process. Meantime,the preparation processes were optimized, which obtainted a set of best preparation parameters: the temperature of hydrothermal reaction is180℃, time of hydrothermal reaction is24h, pH of hydrothermal precursors is11, calcining temperature is500℃, calcination velocity is10℃/min, calcining time is2h. The structure and chemical properties of the catalysts were characterized by XRD, SEM, BET, EDX, XPS, DRS, FT-IR, PL and Zeta potential analysis technology. The synthesized C/Fe-Bi2WO6catalysts are slice-shape nanostructures, good crystal structure, specific surface area12.30m2·g-1. The samples have macroporous and mesoporous structure. The catalyst can furtherly improve to absorb visible lights, and widen avaible pH range for Fenton treatment of FQs. The C/Fe-Bi2WO6and H2O2oxidant, as photocatalyst and oxidant respectively, performed good degradation effect for NOR. The degradation process comply with L-H pseudo-first-order kinetics model, with the reaction kinetic constants0.0751min-1.In the end, the prepared C/Fe-BiVO4as photocatalyst were conducted to the photocatalytic oxidation of CIP, some factors with respect to CIP removal were examined through the single factor experiment. The results show that the removal efficiency of CIP is96.18%; the prepared C/Fe-Bi2WO6as photocatalyst, were conducted to the photocatalytic oxidation of NOR, some factors about the removol of NOR were examined through the single factor experiment and the multivariate experimental design. The results show that the removal efficiency of NOR is91.66%, and the TOC removal efficiency is also able to reach more than60%under the optimum processing condition. Adopting the method of adding inhibitor and molecular fluorescence spectrometry from two aspects of qualitative and quantitative, we determined the production of hydroxyl radicals in the C/Fe-Bi2WO6photocatalytic oxidation to remove NOR system. The addition of C/Fe-Bi2WO6 catalyst have significant effect on the generation amount of·OH radical through comparing different process, proves that the generation amount of·OH radical is much larger than that of other processes, and further illustrated that there was a synergistic effect between the two photocatalyst and Fenton technology, and can greatly improve the·OH generation in H2O2oxidation system, thereby enhancing the removal efficiency of NOR. Combined with the analysis results of LC-MS, possible degradation paths and intermediate products of NOR were speculated. |
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