Study On The Synthesis Of Bismuth Titanate And Titanium Dioxide Heterogeneous Junction By Solvothermal Method And Its Catalytic Performance

In recent years, the water pollution caused by hazardous organic chemicals used in industry and agriculture is a very serious problem. So the research on treatment technology for contaminated raw water becomes more and more vital. In photocatalysis technology, titanium dioxide (TIO2) has been widely studied as an efficient photocatalyst for the photodegradation of pollutants in waste water owing to its inexpensiveness, strong oxidizing power, non-toxicity and long-term photo stability. However, TiO2 can only be excited by UV light irradiation due to its large band gap (3.2 eV). In order to improve the visible activity of TiO2, titanium oxide and other semiconductor composite material was studied. Heterojunction of titanium oxide and bismuth titanate has high visible light activity because of the narrow gap width of bismuth titnante and heterojunction conducive to the advantages of electronic-hole separation. This article main research content is as follows.The Bi2Ti2O7/TiO2 heterojunction nanomaterials were prepared by solvent-thermal method, using ethanol and glycerol as solvent, Bi(NO3)3·5H2O and Ti(BuO)4 as reactants. The prepared catalysts were characterized by XRD, SEM, UV-Vis and Zeta technology. At the same time there were some electrochemical characterization using the cyclic voltammetry and impedance, With chlortetracycline hydrochloride, tetracycline hydrochloride and levofloxacin as the goal pollutant, under the irradiation of simulated sunlight metal halide lamp, examined the photocatalytic performance of the sample. The experimental results show that compared to Bi2Ti2O7 and TiO2, The spectral response range of Bi2Ti2O7/TiO2 heterojunction widening to 600 nm, surface area is more larger, at 80.38 m2/g. Electron transfer and separation of electrons and holes were faster. In the photocatalytic degradation experiments, Bi2Ti2O7/TiO2 heterojunction has the highest degradation rate, Removal rate of the three kinds of antibiotics reached 98.66%,97.91% and 95.66%; with Bi2Ti2O7 as catalyst, removal rate of the three kinds of antibiotics were 90.60%,93.19% and 88.86%; with TiO2 as catalyst, removal rate of the three kinds of antibiotics were 72.74%,86.57% and 90.13%. Photodegradation reaction meets the A kinetic equation.Using ethanol and glycerol as solvent, Bi(NO3)3·5H2O and Ti(BuO)4 as reactants, Different kinds of pure phase bismuth titanate and titanium oxide composite materials had been synthesized by controlling the solvent ratio and calcination temperature. Just as Bi2Ti2O7/TiO2, Bi4Ti3O12/TiO2, Bi2Ti4O1/TiO2, Bi20TiO32/TiO2 heterojunction. The prepared catalysts were characterized by XRD, FE-SEM, HR-TEM, TG-DTA, FT-IR, BET, and UV-Vis technology. At the same time there were some electrochemical characterization using the cyclic voltammetry and impedance, With methylene blue, chlortetracycline hydrochloride, tetracycline hydrochloride and levofloxacin as the goal pollutant, under the irradiation of simulated sunlight metal halide lamp, examined the photocatalytic performance of the samples. The experimental results showed that the forbidden band width of bismuth titanate series heterojunction is 2.33-2.92eV. Compared with TiO2 that were prepared by solvent-thermal method, the surface area of Bi2Ti2O7/TiO2, Bi4Ti3O12/TiO2, Bi2Ti4O11/TiO2, Bi20TiO32/TiO2 were 80.38,37.25,13.50 and 13.86m2/g, the surface area of TiO2 was 9.08m2/g。With Bi2Ti4O11/TiO2. Bi2oTi032/TiO2、Bi4Ti3O12/TiO and Bi2Ti2O7/TiO2 as catalyst, removal rate of the methylene blue were 99.6%,98.1%,91.1% and 84.9%; removal rate of the chlortetracycline hydrochloride were 99.1%,98.4%,97.5% and 98.2%; removal rate of the tetracycline hydrochloride were 99.3%,99.1%,97.2% and 98.2%; removal rate of the levofloxacin were 98.3%,97.1%,96.5% and 95.3. Bismuth titanate series heterogeneous electron transfer faster in the electroche-mical performance. The structure and morphology of the heterojunction was effected by the the solvent ratio and calcination temperature affected the heterojunction material composition and morphology.