柱撑蒙脱石及其热处理产物孔性研究

Microporosity in Al-pillared Montmorillonite and the Calcined Products

用Keggin离子(聚合羟基铝离子)与蒙脱石作用制备了羟基铝柱撑蒙脱石.对羟基铝柱撑蒙脱石及其热处理产物采用X射线衍射分析(XRD)和比表面积(BET法)及孔径分析等方法对其进行了研究.XRD结果表明,羟基铝柱撑蒙脱石底面间距约为2.13nm,热处理(300-650℃)后转变为1.74nm左右.分析表明,铝柱撑蒙脱石比表面积增大为231.6m2/g,比原始蒙脱石增大约7倍.比表面积的增大主要是由于微孔的比表面积的增加,说明柱撑过程主要使蒙脱石的微孔孔隙增多.经热处理后,铝柱撑蒙脱石的孔性发生了很大变化:随着处理温度升高,其比表面积降低,平均孔径增大,微孔体积减少.比表面积的降低主要是由于微孔比表面积的降低.说明热处理使得铝柱撑蒙脱石微孔结构遭到破坏.

Al-pillared montmorillonite prepared with Keggin cation and the calcined products at different temperature were studied by means of XRD, specific surface area analyses and pore size distribution. The results showed that, when calcined from 300 to 650℃, the d value of pillared-montmorillonite changed from 2.13nm to 1.74nm, and the specific surface area was increased to 231.6m2/g. The microporosity of pillared montmorillonite changed because of calcination, with the increase of temperature, the specific surface area was reduced, average pore size was increased, and volume of micropores decreased. Calcination destroyed the micro-structure of Al pillared montmorillonite.