2 The Preparation And Photocatalytic Degradation Of Antibiotic Iodide Modified TiO

KI-I2doped mesoporous TiO2(IT) was prepared by hydrothermal method, using tetrabutyl titanate as precursor, potassium iodate and iodine as iodine sources. The as-prepared IT catalysts were characterized by UV-Vis、XRD、BET、TG/DTA、XPS and FE-SEM. The impact of calcination temperature on the structure and properties of the catalyst has been inspected. The results showed that KI-I2could reduce crystallization temperature of TiO2; anatase structure for IT catalysts could be obtained under the conditions of calculation at80℃. Iodine content in catalysts and mesoporous structure is influenced by calcinated temperature. Because of KI-I2doped, band gap of TiO2has been reduced and specific surface area and visible light absorption propertie of TiO2has been increased. Degradation of methylene blue (MB) by IT-200samples has been improved significantly. Removal rate for40mg/L of MB solution with IT-200under a100W halogen lamp irradiated for1h is80%, and that removal rate is9%by pure TiO2under the same condition.Poly-vinyl alcohol (PVA)-iodine complex doped mesoporous TiO2(PIT) catalysts were prepared by hydrothermal method, using tetrabutyl titanate as precursor, potassium iodate and iodine as iodine sources. The as-prepared PIT catalysts were characterized by UV-Vis、XRD、BET、TG/DTA、XPS and FE-SEM. The photocatalytic activity of catalysts was evaluated through photocatalytic decolorization of MB aqueous solution. The results showed that PIT samples were anatase mesoporous TiO2and their iodine content and mesoporous structure were influenced by calcinated temperature. Particle size of PIT samples was smaller than that of IT as a result of the PVA skeleton and regular structure. Because of the complexation of iodine and PVA, thermostability of iodine has been improved and the amount of iodine in PIT calcinated at200℃(PIT-200) is higher than that of IT-200calcinated at the same temperature. Light absorption range and intensity of PIT-200has been greatly improved due to the synergy of iodine and carbon. The efficiency of photocatalysis for MB is greatly improved with TiO2modified by PVA-I complex under simulated sun light irradiation. Removal rate of MB solution of40mg/L could reach90.2%irradiated by PIT under100W metal halide lamp for1h.12.8%and81.2%higher than the IT-20080.0%and P259.0%, respectively.Study on photocatalytic degradation of tylosin (TYL), norfloxacin (NOR), sodium sulfadiazine (SDZ), and tetracycline hydrochloride (TC) in water was carried out by simulated sunlight irradiation. The influence of amount of catalyst, pH of solution, initial concentration of solution, reaction time on the removal efficiency of antibiotics has been investigated. The results show that the four antibiotics could be removed under the experiment. When the initial concentration of antibiotics is O.lmmol/L and catalyst dosage is lg/L, the removal efficency of norfloxacin (pH=6), tetracycline hydrochloride (pH=4), sodium sulfadiazine (pH=4), and tylosin (pH=6) are98.2%,96.7%,91.8%and90.7%separately. Photodegradation reactions of four antibiotics are according with pseudo-first order reaction kinetic model.