用吸附数据对硅胶表面的分形分析

Surface Fractal Analysis of Silica Gel by Using Adsorption Data

根据一种中孔硅胶对甲酸、乙酸、丙酸和四氯化碳蒸气吸附等温线的单层区域和毛细凝结区域的数据以及自四氯化碳稀溶液中吸附系列脂肪醇的结果计算了该硅胶表面分形维数 D.除了由吸附四氯化碳等温线毛细凝结区域所得 D值低于 2外 ,由其它吸附数据得出的该硅胶的分维 D近似相等 ( D=2 .0 6± 0 .0 5 ) .中孔硅胶低 D值可用其孔结构特性解释 .

The surface fractal dimension D of a mesoporous silica gel were determined by adsorption method.The method is based on the adsorption isotherms of formic, acetic, propionic acids and carbon tetrachloride vapours on the silica gel, and adsorption isotherms of normal aliphatic alcohols from dilute carbon tetrachloride solutions by the silica gel. The obtained fractal dimension D values are similar values to those obtained by using some other method, which are close to two(D=2.06+0.05). But the D value determined by adsorption data in the capillary condensation reigime CCl 4 vapour is lower than 2. The low D values can be explained in terms of the characteristic the porour structure of the silica gel.