Preparation Of Nano-WO 3 By Hydrothermal And Microwave Hydrothermal Methods And Its Photocatalytic Properties

With the development of printing and dyeing industry,a large number of organic dyes are used as coloring materials,all kinds of dyes annual output of about one million tons,the dye produced by the printing and dyeing wastewater to the environment has brought tremendous pressure.Part of the dye due to the toxicity and carcinogenicity,will cause great harm to the human body,so the treatment of dye wastewater is particularly important.In recent years,scientists have been working on the study of semiconductor heterogeneous photocatalytic oxidation of organic pollutants.Tungsten trioxide has the characteristics of high efficiency photocatalytic degradation of organic pollutants,small environmental pollution.In addition,China is the world’s most abundant tungsten ore resources in the country,for the WO₃ provides a rich source.The special structure and morphology are the important factors that affect the properties of the materials.At present,there are still a lot of research space to study the phase,microstructure and crystal growth of tungsten oxide hydrate powder.The main work and the results obtained are as follows:（1）The tungsten oxide nanometer powder was prepared by conventional hydrothermal method using sodium tungstate as the tungsten source and maleic acid as auxiliary agent.The samples were prepared by X-ray powder diffraction（XRD）and scanning electron microscopy（SEM）The photocatalytic activity of tungsten oxide in the degradation of methylene blue was studied by UV irradiation.The results showed that the addition of 0.5 g of maleic acid as the structural adjusting agent with sodium tungstate and hydrochloric acid as the raw material and the pH value of the solution was 0.5,150 ℃ for 24 h,the hexagonal hexagonal WO₃ was prepared and the degradation of methylene blue Rate of 76.4356%.（2）WO₃ was synthesized by microwave hydrothermal method using sodium tungstate and hydrochloric acid as raw materials and maleic acid as auxiliary agent.The samples were characterized by X-ray powder diffraction（XRD）and scanning electron microscopy（SEM）.The obtained samples were used as the catalyst,and the organic dye methylene blue was used as the model,and the photocatalytic degradation experiment was carried out.The results showed that 0.5g of maleic acid was used as the structural adjusting agent with sodium tungstate and hydrochloric acid as the raw materials,and the solution pH was 1,150 ℃ microwave hydrothermal reaction for15 min.The monoclinic phase structure WO₃,The degradation rate of up to 96.77%.（3）Tungsten oxide nanopowders were prepared by microwave hydrothermal method and conventional hydrothermal method using sodium tungstate and hydrochloric acid as raw materialsand acetic acid as additives.X-ray powder diffraction（XRD）and scanning electron microscopy（SEM）Means to characterize the sample.The obtained samples were used as the catalyst,and the organic dye methylene blue was used as the model,and the photocatalytic degradation experiment was carried out.The effects of the synthesis conditions of the tungsten oxide nanopowders on the structure,morphology and photocatalytic activity of the products were discussed.The results showed that the degradation rate of methylene blue was tetrachrome,and the degradation rate of methylene blue was prepared by adding 10 ml acetic acid as the structural adjusting agent with sodium tungstate and hydrochloric acid as the raw material.The pH value was 0.5,150℃ for 24 h.67.5438%.