The new correlation between microporosity of strictly microporous activated carbons and fractal dimension on the basis of the Polanyi-Dubinin theory of adsorption

Adsorption on microporous fractal carbons is investigated in terms of their microporous structure. The structure is characterised by the micropore-size distribution (MSD) proposed by Pfeifer and Avnir, and the considerations are limited only to the range of micropores. following the IUPAC classification. Beginning with numerical studies: performed for model solids with different microporosity. a new relationship between the parameters of the Dubinin-Astakhov equation (adsorption energy, E-0, and parameter n(DA)) and the fractal dimension (D) is derived. The obtained results are compared with those published by Jaroniec et al. and Ehrburger-Dolle. The general conclusion is that if adsorption proceeds by a micropore filling mechanism and the pore size distribution function is assumed to be the Pfeifer and Avnir one, the relationship between D and parameters of the Dubinin-Astakhov equation is more complicated than has been presumed up to the present. (C) 2001 Elsevier Science Ltd. All rights reserved.