H-K法研究ACFs的微结构

STUDY MICROSTRCTURE OF ACFs BY H-K METHOD

ACFs的吸附性能主要取决于比表面积和孔隙结构 ,在不同相对压力下的吸附行为对应不同的孔隙结构。在一定范围内微孔是决定吸附能力大小的重要因素。以 N2 吸附等温线为依据 ,采用 H- K法考察了不同比表面积 ACFs在微观结构以及吸附性能上的差异。采用 BET法计算比表面积 ,Hovath- Kawazoe方程表征微结构。研究表明 ACFs含有大量的小于 0 .7nm的极微孔 ,这些极微孔对吸附等温线的贡献较大 ,并且在吸附过程中赋予ACFs分子筛特性。同时发现随着 ACFs比表面积的增加极微孔的分布相应变宽。

The adsorptive capacity of ACFs correlates mainly with the specific surface area and porous structure, moreover, the adsorption at different relative pressure matches with different pore size distribution. To some extent micropore structure is the most important factor to determine the adsorptive capacity. In the present study, the microstructure and adsorptive capacity of ACFs with different specific surface area are systematically investigated employing N 2 adsorption isotherm. The specific surface area of samples is calculated from the BET method, the microstructure is obtained from Horvath Kawazoe method. It is shown that there are plenty of ultramicropores (width less than 0.7 nm) in the ACF, which make ACF having the function of molecular sieve, and the pore size distribution of ACF becomes wider with increasing surface area. It is of interest to note that both the isotherm at supper low relative pressure and the normal one belong to type I.