Improved pore-size analysis of carbonaceous adsorbents

被引:42
作者
Choma, J [1 ]
Jaroniec, M
Kloske, M
机构
[1] Mil Tech Acad, Inst Chem, PL-00908 Warsaw, Poland
[2] Kent State Univ, Dept Chem, Kent, OH 44242 USA
关键词
D O I
10.1260/026361702760254487
中图分类号
O69 [应用化学];
学科分类号
081704 ;
摘要
An improvement was proposed for the pore-size analysis of active carbons based on low-temperature (77 K) nitrogen adsorption isotherms measured over a wide range of relative pressures (5 x 10(-7)-0.995). It was shown that the applicability of the Barrett, Joyner and Halenda (BJH) computational method based on the Kelvin equation could be extended significantly towards small mesopores and large micropores when a proper t-curve was used to represent the film thickness of nitrogen adsorbed on the carbon surface. It was proposed that the aforementioned t-curve be obtained from the nitrogen adsorption isotherm at 77 K on a macroporous carbon black by fitting its multilayer part to the calibrated t-curve for nitrogen adsorbed at 77 K on a macroporous silica. To date, the Harkins-Jura or Halsey t-curves have been used to describe the pressure-dependence of the film thickness. This appears to be inaccurate, especially in the range of low relative pressures. It was shown that this inaccuracy makes the pore-size analysis questionable. However, the t-curve proposed in this work gave the pore-size distribution functions for the carbons studied thereby reproducing the total pore volume and showing realistic behaviour in the range at the borderline between micropores and mesopores.
引用
收藏
页码:307 / 315
页数:9
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