Preparation Of Vanadate,Molybdate Micro/Nanometer Materials And Their Application In Water Pollution Treatment

With the rapid development of society,the water pollution has become one of the major problems due to various arbitrary discharge of industrial and domestic wastewater.Among all kinds of pollutants,printing and dyeing wastewater are the most difficult to deal with,because it often contains refractory and toxic organic pollutants.So how to effectively remove these pollutants become a serious problem for the number of scientific and technological workers.In recent years,nano-materials with its efficient,cheap and environmentally friendly features show an unparalleled superiority in the field of water treatment,which can achieve rapid adsorption or degradation of water pollutants.In this thesis,a series of vanadate and noble metal complex micro/nanometer materials were prepared by liquid phase synthesis.And the influence of the relevant experimental conditions on the structure and morphology of the samples was studied.According to the experimental phenomena,the possible mechanism was put forward.Meanwhile,the application of synthetic materials in water treatment was also studied.The main contents are as follows:1.With the assistance of nonionic surfactant polyvinylpyrrolidone?PVP?,flower-like clusters Zn₃?OH?₂V₂O₇·2H₂O were synthesisd via a simple chemical precipitation method.The structure and morphology were characterized by XRD,FT-IR and SEM.As adsorbent to treat organic dyes,the result showed that flower-like clusters Zn₃?OH?₂V₂O₇·2H₂O exhibited a superior adsorption performance for anionic dyes MB compared with activited carbon,due to its abundant pore structure,large specific surface area and suface electronegativity.The adsorption thermodynamics of the flower-like clusters Zn₃?OH?₂V₂O₇·2H₂O on MB was in accordance with Freundlich model,indicating that the adsorbed form was non-monolayer molecule adsorption.And the adsorption process was well fit the pseudo-second-order kinetics model,indicating that the whole adsorption process including external diffusion,internal diffusion and surface adsorption process.At the same time,the intra-particle diffusion equation model fitting results show that the linear relationship between qt and t1/2 is better in the whole adsorption process,but not through the origin?C?0?,therefore,the adsorption process is dominated by intra-particle diffusion control.But the intra-particle diffusion is not the only control step for the adsorption rate.The adsorption heat of this process is 47.3 KJ/mol,which indicates that the process was mainly based on physical adsorption.On the basis of the above work,a series of Zn_3-x?Cu_x??OH?₂V₂O₇·2H₂O complexes were successfully synthesized by precipitation method.Their structures and morphologies were characterized by XRD,SEM and PL.And the influence factors of photocatalytic activity of Zn_3-x?Cu_x??OH?₂V₂O₇7·2H₂O were studied.The results show that the value of x is from 0 to 3,the morphology of Zn_3-x?Cu_x??OH?₂V₂O₇·2H₂O complex changes from flower cluster to granular,and the particle size becomes smaller gradually.Zn_3-x?Cu_x??OH?₂V₂O₇·2H₂O was used as photocatalyst for the degradation of RhB,the results showed that the photocatalytic activity was the best when the value of x is 2.That is to say,the ratio of zinc and copper to 2:1 is the best for solid solution.The activity of pure copper pyrophosphate is relatively high?x=3?,mainly due to its small size effect;the pure zinc pyrovanadate activity is higher than that of solid solution Zn3-x?Cu,??OH?2V2O7·2H2O?x=1?due to its unique structure.The hierarchical flower like zinc pyrovanadate could transfer effectively to catalytic reactants and products,which has more advantages than the granular morphology of samples.2.A series of AgBr/CaMoO₄ composite catalysts were prepared by a simple liquid phase precipitation method and the samples were characterized by XRD,FT-IR,SEM and XPS.It was found that the catalytic effect of AgBr/CaMoO₄ was higher than that of pure AgBr and CaMoO₄ in the presence of sodium borohydride?NaBH₄?,and the activity of the composite catalyst was the highest when the loading of AgBr was 5%.By analysis,the composite sample microspheres CaMoO₄ were mainly as carrier,which can make AgBr nanoparticles uniformly dispersed on the surface of AgBr to prevent their reunion,so that AgBr can fully contact reaction molecules?BH4-and p-nitrophenol ion?,and greatly improve the catalytic activity of complexes.