Ustinov E A, Do D D, Jaroniec M
Saint Petersburg State Technological Institute (Technical University), 26, Moskovsky Prospect, 190013 Saint Petersburg, Russia.
J Phys Chem B. 2005 Feb 10;109(5):1947-58. doi: 10.1021/jp046534u.
This paper presents a thermodynamic analysis of capillary condensation phenomena in cylindrical pores. Here, we modified the Broekhoff and de Boer (BdB) model for cylindrical pores accounting for the effect of the pore radius on the potential exerted by the pore walls. The new approach incorporates the recently published standard nitrogen and argon adsorption isotherm on nonporous silica LiChrospher Si-1000. The developed model is tested against the nonlocal density functional theory (NLDFT), and the criterion for this comparison is the condensation/evaporation pressure versus the pore diameter. The quantitative agreement between the NLDFT and the refined version of the BdB theory is ascertained for pores larger than 2 nm. The modified BdB theory was applied to the experimental adsorption branch of adsorption isotherms of a number of MCM-41 samples to determine their pore size distributions (PSDs). It was found that the PSDs determined with the new BdB approach coincide with those determined with the NLDFT (also using the experimental adsorption branch). As opposed to the NLDFT, the modified BdB theory is very simple in its utilization and therefore can be used as a convenient tool to obtain PSDs of all mesoporous solids from the analysis of the adsorption branch of adsorption isotherms of any subcritical fluids.
本文介绍了圆柱孔中毛细凝聚现象的热力学分析。在此，我们对圆柱孔的布罗克霍夫和德布尔（BdB）模型进行了修正，考虑了孔径对孔壁所施加势能的影响。新方法纳入了最近发表的在无孔硅胶LiChrospher Si - 1000上的标准氮气和氩气吸附等温线。所开发的模型与非局部密度泛函理论（NLDFT）进行了对比测试，这种对比的标准是凝聚/蒸发压力与孔径的关系。对于大于2nm的孔，确定了NLDFT与BdB理论改进版本之间的定量一致性。修正后的BdB理论应用于多个MCM - 41样品吸附等温线的实验吸附分支，以确定它们的孔径分布（PSD）。结果发现，用新的BdB方法确定的PSD与用NLDFT（同样使用实验吸附分支）确定的PSD一致。与NLDFT不同，修正后的BdB理论在应用上非常简单，因此可以作为一种便捷工具，通过分析任何亚临界流体吸附等温线的吸附分支来获得所有介孔固体的PSD。
