| Semiconductor materials was widely used in chemical industry, environment, medicine and electronics fields owing to its unique optical, magnetic, electric and other characteristicshave become one of the most popular research material. TiO2, CdS, CdSe, CoFe2O4, ZnFe2O4 act as one of the most widely used photocatalyst, among many semiconductor materials, has a unique advantage in photocatalytic degradation of organic pollutants in wastewater treatment residues. But ordinary photocatalytic materials have some defects such as the low second utilization rate, the not high photocatalytic activity, no selective seriously that restrict its potential development and application space. In order to overcome the above problems, it is inevitable that the combination with the magnetic materials and photocatalytic materials as well as the molecular imprinting technique and the photocatalytic technology.Above all, the high photocatalytic activity and other well performance of the composite photocatalyst, applied to photocatalytic degrade of antibiotic organic pollutants residuesin the environment, was prepared though the load, composite, doping and surface modification on many semiconductor materials, which is for achieving the purpose of removal of antibiotic residues organic pollutant in the environment. This work mainly includes three aspects as following: 1. Design of composite photocatalyst based on TiO2 and Research on photocatalytic performance(1) Chitosan heteropoly acid/TiO2 composite photocatalysts were successfully prepared by sol-gel method, hydrothermal method and impregnation method. The following conclusions are obtained by a series of characterization that the structure of Keggin was not damaged and the backbone structure of chitosan was retain completely, when the conductive polymer was forming between heteropoly acid and chitosan. It can be seen from the activity test that the amount of chitosan and heteropoly acid is the factors to affect the photocatalytic activity. Among them, the PMA-CS/TiO2 has the best photocatalytic activity in this experiment and the photocatalytic degradation rate of tetracycline can reach 83%. The acid of phosphotungstic is the best in heteropoly acid, but the acid of composite photocatalyst is not the key factors of affecting the photocatalytic activity.(2) Taking OPD and MPD as conductive polymers, Fe3+@POPD-PMPD/TiO2 /HNTs composite photocatalysts were synthesized with different proportion of functional monomer. Ion loss and ion loading of prepared composite photocatalyst were analysed by inductively coupled plasma emission spectrometry. The photocatalytic degradation experiment shows that Fe3+@POPD-PMPD/TiO2/HNTs composite photocatalyst wtih the proportion of OPD and MPD is 4 or 5 as well as the proportion of Fe3+has the best photocatalytic activity under condition of pH 3, and then the photocatalytic degradation rate of tetracycline with the concentration was 40 mg L"1 could reach 75.96%.2. Synthesis of high efficient photocatalyst based on cadmium and research on photocatalytic performance(1) Under alkaline conditions, metal ion doped CdSe quantum dots photocatalysts were successfully prepared by hydrothermal method. Co doped CdSe quantum dots photocatalyst showed excellent photocatalytic activity to tetracycline hydrochloride under visible light irradiation. Photocatalytic degradation efficiency of Co doped CdSe quantum dots photocatalyst is more prominent in the presence of cationic surfactant and the photodegradation rate could reach 85.47%. In addition, the catalyst efficiency of Co doped CdSe. quantum dots photocatalystalmost remains unchanged after repeated experiments, which prove that the photocatalyst has good stability.(2) The novel CdS/MFACs composite photocatalyst was successfully prepared by chemical deposition method. The results show that CdS nanoparticles can be loaded on the surface of MFACs, and the new CdS/MFACs composite photocatalyst can be quickly separated by an external magnetic field. Meanwhile the CdS/MFACs composite photocatalyst has higher absorption properties and photocatalytic activity under visible light irradiation. In addition, the free radical experiments show that degradation and mineralization of danofloxacin mesylate was mainly related to ·O2-and photogenerated holes.3. Design of the ferrite composite photocatalytic materials and research on photocatalytic behavior(1) The ZnO/ZnFe2O4 composite photocatalyst was prepared by solvothermal method and sol-gel method and was applied to photocatalytic degrade ciprofloxacin. Experiments show that theZnO/ZnFe2O4 composite photocatalyst has high photocatalytic performance and degradation rate could reach 70.86%. In addition, through studying the effects of different exogenous cationicand exogenous anionic and different pH values on photocatalytic performance of ZnO/ZnFe2O4 composite photocatalyst, we found that cation, anion and pH have a great influence on the whole system, in which Mg2+ is helpful to improve the photocatalytic activity, and the photocatalytic degradation rate could reach 93.34%. When the pH value is 7, the photocatalytic degradation efficiency of ZnO/ZnFe2O4 composite photocatalyst is best, the degradation rate could reach 95.73%.(2) The compound magnetic conductive imprinted photocatalyst CoFe2O4/C was fabricated by CoFe2O4/C. And the CoFe2O4/C was constructed by the corncob carbonization (C), and then loaded or coated with CoFe2O4. Experiments show that the different dosage of conductive polymer functional monomer Ag@PANI and different dosage of template molecule (tetracycline) and different polymerization timehas great influence on the photocatalytic activity ofnew magnetic conductive imprinted CoFe2O4/C composite photocatalyst. When the dosage of Ag@PANI was 0.01 g and the dosage of tetracycline was lmmol and reaction time was 15 min, the new magnetic conductive imprinted CoFe2O4/C composite photocatalyst has the best best photocatalytic activity, and the photodegradation rate could reach 82.23%. |
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