The Study Of Preparation, Characterization And Photocatalytic Application Process Of Doping Bi-Containing Photocatalysts

At present, many industrial wastewaters have lots of characteristics, such as high concentration of organic substance, biodegradable and biological toxicity. Especially, the phenolic compound in industrial wastewater is most harmful, and the harm is persistent. Therefore, to explore an effective treatment technology of phenol-containing wastewater is imminent. As a new pollution treatment technology, photocatalytic oxidation is an enhanced and improved chemical oxidation method. Compared with other traditional water treatment method, the photocatalytic oxidation have a lots of advantages, such as, mild reaction conditions, low treatment cost, high oxidation effect, good selectivity, fast reaction speed, and organic volatile phenol can be oxidized to non-harmfully inorganic compounds. So, the photocatalytic oxidation has been widely studied.The study mainly centers on the basic science and technology issues in the synthesis and photocatalytic oxidation application of photocatalytic materials. The synthesis mechanism, structure characteristics and photocatalysis process of Bi-containing photocatalysts are reasearched. Lots of basic theory and rules of synthesis process and application process of Bi-containing photocatalysts are explored. The results hereby can provide the theoretical reference for phenol wastewater treatment by photocatalytic oxidation. The following several aspects of research are discussed in this paper:1. The Cu doping Bi2WO6photocatalysts are prepared by hydrothermal method and characterized by XRD、XPS、DRS and SEM. The results show that, after doped Cu, the Cu-Bi2WO6photocatalysts has a significant red-shift in the absorption band, and the absorption intensity increases greatly in the visible region. When the amount of Cu doping is0.5wt%, diffraction peaks of Cu-Bi2WO6are sharp and Cu-Bi2WO6has a higher crystallinity. While the pH value of preparation is0.6, the diffraction peaks are most narrow and the peak intension is larger. The morphology and microstructure of Cu-Bi2WO6is3D flower spherical structure, the size of micro-porosity is large, and specific surface area is84.58m2/g.2. The various factors of photocatalytic degradation of phenol-containing wastewater over Cu-Bi2WO6photocatalysts are discussed by single factor experiment. The results show that the optimal degradation effect of phenol-containing wastewater could reach at a Cu-Bi2WO6catalyst (pH value of preparation is0.6, Cu doping is0.5wt%) dosage of1.0mg/L, and an air flow rate of25mL/min upon being illuminated with300W metal halide lamp. Cu-Bi2WO6dosage, air flow, light, light intensity as a multiple factor, the degradation effect is investigated by interaction of multiple factors, the results show that the establishment of the regression model was significant, orrelation coefficient R2is0.9658.3. The model equations of adsorption of phenol over Cu-Bi2WO6, Qe=0.31437Ce/1+0.02286Ce and Qe=0.57298Ce0.66154, are established. Both types of isothermal adsorption model can descript the adsorption phenomena of phenol over Cu-Bi2WO6.Based on Langmuir-Hinshewood model, the kinetics equation of photocatalytic degradation of phenol-containing wastewater is established. The correlation coefficient R2is0.9919, and kinetic parameters of Langmuir-Hinshewood model are k=0.8126, KL-H=0.02354. The Cu doping BiVO4photocatalysts are prepared by hydrothermal method and characterized by XRD、XPS、DRS and SEM. The results show that, the Cu-BiVO4preparated at neutral conditions belongs to the monoclinic crystal system scheelite, the diffraction peaks are most narrow, the peak intension is larger. When the amount of Cu doping is0.75wt%, diffraction peaks of Cu-BiVO4are sharp and Cu-BiVO4has a higher crystallinity. While the pH value of preparation is7, the morphology and microstructure of Cu-BiVO4is3D spherical structure and has a complicated surface morphology, the size of micro-porosity is large, and specific surface area is12.64m2/g.5. The various factors of photocatalytic degradation of phenol-containing wastewater over Cu-BiVO4photocatalysts are discussed by single factor experiment. The results show that the optimal degradation effect of phenol-containing wastewater could reach at a Cu-BiVO4catalyst (pH value of preparation is7, Cu doping is0.75wt%) dosage of1.0mg/L, and an air flow rate of30mL/min upon being illuminated with300W xenon lamp. Cu-BiVO4dosage, air flow, light, light intensity as a multiple factor, the degradation effect is investigated by interaction of multiple factors, the results show that the establishment of the regression model was significant, orrelation coefficient R2is94.93%. 6. The model equations of adsorption of phenol over Cu-BiVO4, Qe=0.83986Ce/1+0.01254Ce and Qe=0.760606Ce0.76684,are established. Both types of isothermal adsorption model can descript the adsorption phenomena of phenol over Cu-BiVO4Based on Langmuir-Hinshewood model, the kinetics equation of photocatalytic degradation of phenol-containing wastewater is established. The correlation coefficient R2is0.9961, and kinetic parameters of Langmuir-Hinshewood model are k=0.4652, KL-H=0.0695The obtained outcome of this study, not only enriches the contents of materials chemistry and environmental science, but also provides a new idea to prepare metal composite oxides materials with diverse surface structure and photocatalytic properties, and also provides a consulting effect to photocatalytic treatment of industrial wastewaters with metal composite oxides materials.