Preparation Of Bismuth Tungstate Nanocomposite Photocatalysts And Its Application Research

Because of the high COD,large water,high colority,complicated composition,difficult to biodegrade and great harm to human health and safety,dyeing wastewater has become one of the hardest treated kinds of industrial wastewater.It is difficult to make water meet the quality standards if we use the traditional treatments.Photocatalytic technology can not only use clean and pollution-free solar energy,but also can degrade most of the organic compounds under mild conditions without secondary pollution,which greatly reduced the harm of organic pollutants on the human body and ensured the safety of human life and property.Bi₂WO₆,as the best visible-light photocatalytic activity semiconductor material,whether the material itself or the raw materials are non-toxic andpreparation methods are also safe and effective.The preparation of visible-light photocatalyst Bi₂WO₆ and its composites Bi₂WO₆/GO,Bi₂WO₆/NG and its degradation effect of four kinds of simulated dye wastewater under xenon lamp simulated daylight condition were studied in this work.1.In this research,Bi₂WO₆ photocatalyst with three dimensional flower-like structure was synthesized by hydrothermal method which used Na2WO4·2H2O and Bi（NO3）3·5H2O as raw materials in order to explore the optimum preparation conditions.The structure and morphology of Bi₂WO₆ photocatalyst were characterized by SEM and XRD.The experimental results showed that Bi₂WO₆ which has highest photocatalytic activity was in the preparation of hydrothermal reaction for 24 h in precursor liquid pH=1,160℃.The effect of catalyst dosage,the initial concentration of rhodamine B,light intensity and reaction time on the degradation of Rhodamine B was also investigated,the results indicated that in the 500 W light intensity,adding 0.05 g Bi₂WO₆ to the concentration of 1.0×10-5 mol·L-1 of Rhodamine B solution,the removal rate reaches the maximum,up to 90.1% at the reaction time of 60 minutes.2.Go was synthesized by Hummers method,and then the Bi₂WO₆/GO composite photocatalyst with different mass fraction was prepared by hydrothermal method using GO and Bi₂WO₆ as raw materials.The morphology and structure of the composite were analyzed by means of TEM and XRD.The degradation effect of compound on four simulated dye wastewater was investigated under optimum photocatalytic reaction conditions,The results showed that the mass fraction of 3% Bi₂WO₆/GO composite photocatalyst which was synthesized by the one-pot method at 160℃ for 12 h has the highest degradation rate to the concentration of 1.0×10-5 mol·L-1 of methyl orange up to 96.1% and the degradation rate to the rest dye was up to about 95%.3.The Bi₂WO₆/NG composite photocatalyst with different mass fraction was prepared by hydrothermal method using GO and Bi₂WO₆ as raw material,urea as nitrogen source.The morphology and structure of the composite were analyzed by means of TEM and XRD.The degradation effect of compound on four simulated dye wastewater was investigated under optimum photo-degradation conditions,The results showed that the mass fraction of 20% Bi₂WO₆/NG composite photocatalyst which was synthesized by the one-pot method at 160℃ for 12 h has the highest degradation rate to the concentration of 1.0 × 10-5 mol·L-1 of rhodamine B,up to 98.9% and the degradation rate to the rest dye was also up to about 98%.4.That Bi₂WO₆ and its composites have very high degradation rate for organic pollutants not only protected the balance of the ecological environment,but also reduced the threat to human health and safety,and it made human,health,and resources more hanmonious and sustainable development.In practical application,using sunlight as visible light source to degradate the dye wastewater can avoid the use of power supply,and is safe and more environmentally friendly..