Preparation Of Bi₂WO₆Photocatalyst And Use For Photocatalytic Degradation Of Tetracycline

Due to the irrational use of antibiotics has caused serious environmental pollutionproblems caused the human production and life and health of the larger negative impact.Photocatalysis which is a promising techniques has been regard as a ideal method to solvethis problem. Bismuth tungstate is one of the most simple members of the Aurivillius oxidefamily and have photocatalytic under visible light. It is have a special layered structure(Theorthorhombic structure is constructed by corner-shared WO6octahedral layers. Bi atomslayers are sandwiched between WO6octahedral layers) lead a lot of attention in thephotocatalytic performance. It has been found that the properties of nano-materials aredetermined by their morphology and structure. Therefore, design and synthesis of bismuthtungstate materials with different morphologies is significantly important in view of bothfundamental research and practical applications, and has stimulated intensive researchinterest.It is reported that nanoparticles, nano-fibers, nano-sheet like, flower-like,tyre-like,helix-like structure of bismuth tungstate structures has been synthesized. But the use ofinorganic synthetic different bismuth tungstate nano-structures has not been reported. Usinga variety of testing methods to their specific structure and phase composition werecharacterized. Specific research work is as follows:In our experiments, we using a simple hydrothermal method to synthesis a series ofbismuth tungstate materials by adding Na2SO4and changing of there pH values. It isincluded three-dimensional(3D) bismuth tungstate nest-like nano-structures,three-dimensional(3D) rod-like nanostructures and quantum dots modified nanoplates. Thecompositions, crystalline phase, microstructure, morphology and band gap energy, specificsurface area of the Bi2WO6samples are characterized by X-ray diffraction(XRD), scanningelectron microscopy(SEM), and transmission electron microscope (TEM), ultraviolet visiblespectrophotometer (UV-vis),etc. The results indicate that the diameter of an individualbismuth tungstate nest-like is about1.5μm and composed of20-50nm nano-sheets; three dimensional(3D) hierarchical Bi2WO6microns rod-like morphology is about10-15μmlength and1μm width and composed of superimposed layers of nano-sheets arrangedthrough the formation; quantum dots-modified nanoplates Bi2WO6with a2D structurednanoplate morphology with a side length of0.5-1μm and a thickness of50-100nm.Possible formation mechanism of forming these samples was proposed by analysis the pHof the reaction, sodium sulfate content and reaction time on the synthesized of nest-like3Dstructure Bi2WO6, rod-like three dimensional(3D) structure Bi2WO6and quantumdots-modified nanoplates Bi2WO6. The photocatalytic activity of the synthesized sampleswas evaluated by monitoring the degradation of antibiotic tetracycline(TC) solution under axenon lamp irradiation(cut off λ≤420nm light through an optical filter). The results showedthat synthesized samples have excellent photocatalytic activity. But the photocatalyticperformance3D structure was better than2D structure, may be associated with3D structurecan improved a greater specific surface area and the relevant contact sites.