Mg-Zn-Al-Fe型类水滑石纳米颗粒的制备及表征

Study on Preparation and Characterization of Mg-Zn-Al-Fe Hydrotalcite-like Compound Nanoparticles

采用液相共沉淀法合成了 4种金属离子 (Mg Zn Al Fe)组成的类水滑石 (简称Mg Zn Al Fe HTlc) ,考察了n(Al+Fe) n(Mg +Zn +Al+Fe) (x)对化学组成、晶体结构、粒子形貌、BET比表面积和等电点 (IEP)等的影响 .结果表明 ,所合成样品为片状纳米颗粒 ,化学组成与原料配比基本一致 ,Mg和Zn的相对含量比原料配比略低 .在所研究条件下 ,x在 0 .2 2～ 0 .36范围内得到纯Mg Zn Al Fe HTlc ,x较高 ( 0 .5 2 )时的产品为非晶体 .Mg Zn Al Fe HTlc的六方晶格参数a和c、层间距、层间通道及IEP基本不随x变化 ;a值为 0 .30nm ,c值约为 2 .30nm ,层间距约为 0 .76 5nm ,层间通道约为 0 .2 8nm ,IEP约为 10 .8.平均晶粒度不随x变化 ,约为 18nm ;TEM法测得的平均粒度随x减小而减小 .BET比表面积随x减小而增大 .制备的Mg Zn Al Fe

The nanoparticles of magnesium zinc aluminum ferric Hydrotalcite like Compound (Mg Zn Al Fe HTlc)was synthesized by coprecipition method, and the effects of n (Al+Fe)/ n (Mg+Zn+Al+Fe) ( x ) on their chemical composition,crystal structure, shape, BET specific surface area and isoelectric point (IEP) et al . were studied. It was found that the Mg Zn Al Fe HTlc particles prepared are plate like nanoparticles, and their chemical compositions are basically consistent with the compositions of raw materials. In the range of x of 0.22～0.36, the pure Mg Zn Al Fe HTlc is formed, and when x is higher than the range the sample prepared is amorphous. The lattice constant ( a and c ) of hexagonal cell, basal spacing, gallery height and IEP of Mg Zn Al Fe HTlc samples don't basically change with the x of the samples. The value of a is 0.30 nm, the value of c is about 2.30 nm, the basal spacing is about 0.765 nm, the gallery height is about 0.28 nm. The mean crystal grain obtained by XRD and Scherrer formula does not basically change with the x of the samples and is about 18 nm. With the decrease of the x of the samples, the mean particle size obtained by TEM decreases and BET specific surface area increases. The particles of Mg Zn Al Fe HTlc samples prepared are polycrystal.