Preparation And Application Research Of Bi-basedsemiconductor Composite Photocatalyst

At present, with the rapid development of industry, the consequent pollution has caused serious environmental problems. Thus reducing environmental pollution, develop some no secondary pollution for environment of technology and efficient clean renewable energy has been imminent. However, the traditional techniques such as adsorption, biological and chemical oxidation method is difficult to deal with the toxic organic pollutants. The photocatalytic degradation of organic pollutants is a kind of chemical oxidation method to strengthen and improve pollution treatment technology, it has a mild process condition, low processing cost, good selectivity, high oxidation effect and faster response speed. and has attracted increasing attention. In this paper, in order to solve bismuth based Bi2S3, Bi2WO6 photocatalyst with high carrier recombination rate, and Research on the compound modification, prepared a new type composite visible light catalyst Zn O/Bi2WO6 and Bi2S3/Zn S.and optimization condition for the synthesis of composite photocatalyst is analyzed, studied the composite photocatalyst photocatalytic treatment effect of wastewater containing phenol, composite photocatalyst on adsorption and catalytic degradation dynamics of wastewater containing phenol. The following several aspects of research were discussed in this paper:1. The Zn O/Bi2WO6 photocatalysts were prepared by hydrothermal method and characterized by XRD、SEM、EDS and BET. The results show that, after doped Bi2WO6, the Zn O/Bi2WO6 has a significant red-shift in the absorption band, and the absorption intensity increased greatly in the visible region. When the amount of Bi2WO6 doping was 4wt%, diffraction peaks of Zn O/Bi2WO6 are sharp and Zn O/Bi2WO6 has a higher crystallinity.2. It was discussed that the various factors of photocatalytic degradation of phenol-containing wastewater over Zn O/Bi2WO6 photocatalysts by single factor method. The results show that the degradation effect of phenol-containing wastewater was optimal when Zn O/Bi2WO6 catalyst(p H=7, Bi2WO6 doping is 4wt%) dosage was 2.5mg/L, and it was illuminated with 250 W metal halide lamp when the initial concentration of phenol were 20 mg/L.3. The Bi2S3/Zn S photocatalysts were prepared by hydrothermal method and characterized by XRD、SEM、EDS and BET. The results show that, the diffraction peaks of the Bi2S3/Zn S which preparated at neutral conditions are most narrow, the peak intension is larger. When the amount of Bi2S3/Zn S was 8wt%, diffraction peaks of Bi2S3/Zn S are sharp and Bi2S3/Zn S has a higher crystallinity. While p H=7, the specific surface area of Bi2S3/Zn S is 10.09 m2/g.4. It was discussed that the various factors of photocatalytic degradation of phenol-containing wastewater over Bi2S3/Zn S photocatalysts by single factor method. The results show that the degradation effect of phenol-containing wastewater was optimal when the catalyst(p H = 7, Bi2S3 doping is 8wt%) dosage reached 2.5mg/L, and it was illuminated with 250 W metal halide lamp. And under the same condition,the Bi2S3 / Zn S catalyst exhibits obviously higher visible light photocatalytic activities than commercial P25.5.The model equations of adsorption of phenol over Bi2S3/Zn S,0.30451=1+0.02144 e CeQCeand 0.699910.50859 e eQ =C, were established based on the Langmuir and Freundlichand. Both two types of isothermal adsorption model could describe the adsorption phenomena of phenol over Bi2S3/Zn S. Based on Langmuir-Hinshewood model, the kinetics equation of photocatalytic degradation of phenol-containing wastewater00157.8305= +1.0058r c was established.