Preparation And Characterization Of Zion Iron Hydrotalcite-like Compounds And Its Composite Oxides

Hydrotalcite-like compounds is a kind of special layer structure with the anion of clay,also called as layered double hydroxides.Because of the collocation of cation and coupled with a wide possible choice of anionic groups, HTLcs become a great potential applications of multi-function inorganic materials.MⅡ FeⅢ HTLcs has a broad prospect of application to Electrical, magnetic,optical and catalytic,etc.In present the research of preparation method for ZnFeⅢ-HTLcs is rarely reported at home and abroad,one of the few report is traditional coprecipitation method,but in the solution,the pH of precipitation of hydroxide which is generated by Zn2+and Fe3+,is respectively6.0～7.0,1.5～2.5, It is hard to precipitate in reaction system at the same time,for large difference of precipitation number,Thus, the product by the method is bad and the crystallinitye is not high.In this paper,the traditional synthesis method of HTLcs was improved,well-crystallized ZnFeⅢ-HTLcs was synthesized by two step method and homogeneous precipitation.The derivate complex oxides of ZnFeⅢ-HTLcs were created by calcining, called Zinc ferrite(ZnFe2O4).it was compared with the products of hydrothermal synthesis method and homogeneous precipitation. The main works consist of four parts:(1) ZnFeⅢ-HTLcs is preparated by two step methodWe choose the solution of ZnSO4and FeSO4for raw materials,NaOH for precipitation agent,use the two step method.First,we make Zn2+-Fe2+coprecipitated in the environment of N2protection to generate ZnFe compound hydrogen chloride,and then use oxidation by H2O2,transform ZnFe compound hydrogen chloride into ZnFe-HTLcs.The influences,such as ration of materials,pH value and the oxidation temperature were discussed.The experimental results show that ZnFe-HTLcs has the high crystallinity and the thermal stability which in the condition of pH=6.0-7.0, n(Zn2+)/n(Fe2+)=2.0-3.0,oxidation temperature is25℃-40℃.(2) ZnFeⅢ-HTLcs is preparated by homogeneous precipitationWe choose the solution of ZnSO4and FeSO4for raw materials,HMT for precipitation agent,get the good crystal shaped high crystallinity by the method of homogeneous precipitation.This paper detailedly describes the ratio of raw material,pH,precipitation agent,reaction temperature and reaction time factors which influence the synthetic products.The results of the research show that ZnFeⅢ-HTLcs has a good layer structure,high crystallinity and good crystal,which compound in the conditions of n(Zn)/n(Fe)=3.0-4.0, n(SO42-)/n(HMT)=1:1.2-1:1.8,at the temperature of Water bath is40℃-60℃:,Reaction time is36h-60h.(3) Characterization of ZnFeⅢ-HTLcs was carried out by XRD,FTIR,N2-adsorption,XPS.(4) We preparate iron acid zinc through the method of calcinating HTLcs,hydrothermal synthesis method and homogeneous precipitation.we compare and analyse the products of the particle diameter,pore size distribution, specific surface area.