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The emergence of antibiotics in the environment and resulting harm is being more and more attention. Enrichment of antibiotics in the environment directly affect ecosystem functions, directly in the body caused by the enrichment of bacterial resistance increased, and thus endanger human health. Select this thesis widespread in the water environment of oxytetracycline and sulfamethoxazole two kinds of antibiotics, study their photochemical reactions in aquatic environments influencing factors, kinetics and degradation pathways aimed at in-depth understanding of its photochemical behavior for the theoretical analysis and provide the basis for practical engineering process. This study consists of three parts. Part I: HPLC was used as oxytetracycline and sulfamethoxazole detection methods, reference to other documents, determine oxytetracycline and sulfamethoxazole testing conditions; using high-pressure mercury lamp and a spherical xenon lamp as a light source, Comparison of UV aqueous solution of oxytetracycline and sulfamethoxazole (SMZ) photodegradation effects investigated various influencing factors, such as pH, DOM, NO3-, photodegradation reaction. The results show that for the initial concentration of 50mg / L solution, UV and simulated sunlight after 60min, oxytetracycline removal rates reached 73.2% and 27.2%, SMZ removal rate amounted to 97.9% and 36.4%, indicating that soil sulfamethoxazole compared with amphotericin more stable, more difficult to photodegradation. Two solutions TOC removal rates reached 17% and 51.1%. As the pH value increases, the removal rate of two types of antibiotics were increased; DOM is showing a different variation, with the increase of HA, oxytetracycline photolysis first increased and then decreased, while sulfamethoxazole was first decreased and then increased; With the solution NO3-concentration increased, the photodegradation effect is enhanced. Part II: The UV / TiO, combined process of oxytetracycline OTC. The effects of the initial concentration of light during the reaction, the catalyst dosage, initial solution pH, solution DOM and N03-photocatalytic degradation effects. On this basis, the light degradation kinetics was studied. The results show that the photocatalytic oxidation can effectively remove the water semi-micro OTC, OTC photodegradation process complies with a kinetic model; OTC from the initial concentration of 30mg · L-1 increased to 90mg · L-1, the reaction rate from 0.0619 min-'reduced to 0.0130min-'; With photocatalyst dosage increases, the light degradation rate constant first increases and then decreases; increase the pH of the solution, the rate constant decreases; solution DOM and N03-existence also affects photodegradation efficiency. UV and UV/TiO2 compare the two systems, with their TOC removal as an indicator, UV/TiO2 system safer and more effective. Detected by HPLC and IR spectroscopy, suggesting that degradation OTC is the removal of the benzene ring substituents, and the substituents on the ring position changes. Part III: To improve the catalytic performance of oxytetracycline visible to tetrabutyl titanate [CH3 (CH2) 30] 4Ti] as the titanium source, iodate [H103] and ferric nitrate [Fe (N03) 3.9 H20] as modifier, using the sol - gel synthesis of the iron-doped nano-Ti02 iodine catalyst. By X-ray powder diffraction (XRD), thermogravimetry - differential thermal (TG-DTG), UV-visible spectroscopy (UV-Vis) catalysts were characterized. The results show that when the calcination temperature was 673K, Fe/I-Ti02 anatase type crystal grain diameter of 11.28nm, UV-visible spectrum red-shifted absorption ,400-600nm range of intensity. 50mg · L-1 oxytetracycline photocatalytic degradation experiments show that the calcination temperature 673K, 0.05% of the amount of iron-doped photocatalytic activity of Ti02 best.
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