### 介孔吸附剂表面分形分析

1. 北京大学化学学院, 北京, 100871
• 投稿日期:2003-03-06 修回日期:2003-09-15 发布日期:2014-01-26
• 通讯作者: 赵振国,E-mail:majm@chem.pku.edu.cn E-mail:majm@chem.pku.edu.cn
• 基金资助:
国家自然科学基金(No.20233010)资助项目.

### Surface Fractal Analysis of Mesoporous Adsorbents

ZHAO Zhen-Guo

1. College of Chemistry and Molecular Engineering, Peking University, Beijing 100871
• Received:2003-03-06 Revised:2003-09-15 Published:2014-01-26

The fractal dimension D values of the mesoporous silica gel and activated carbon have been determined by the method of adsorption from solutions. The results are as follows. (1) The adsorption isotherms of aliphatic alcohols, ketones, esters and oxy aromatic compounds from carbon tetrachloride or cyclohexane on silica gel, and those of aromatic compounds from water on activated carbon can be represented by the Langmuir equation. The fractal dimension D can be calculated by the limiting adsorbed amount, nms, and the apparent molecular across section, σa, based on log nms=-D/2logσa+constant. The nms and σa were calculated with the Langmuir equation and the specific surface area of adsorbents. (2) The fractal dimension D values of the mesoporous silica gel derived by the method of adsorption from solutions are the same as those from gases, which are ca. 2. As long as the radius of the surface curvature is larger than the size of adsorbed molecules, the surface of adsorbent may have low fractal dimension. (3) The obtained fractal dimension D value of the mesoporous activated carbon derived by the method of adsorption from solutions is also close to 2. A possible explanation is that progressive activation changes the microporous structure of the original charcoal gradually to a meso/macroporous structure. Then the mesoporous activated carbon can be also characterized by low fractal dimension.