The structural parameters of microporous solid, including fractal dimension, on the basis of the potential theory of adsorption - The general solution

A program in Fortran has been created on the basis of programs LMDIF taken from the Minpack Library and also from the book Numerical Recipes in Forti an [Press et al. (1992), 2nd edn, Cambridge University Press, Cambridge]. The program permits the calculation of the structural parameters of adsorbents, including fractal dimension, and is based on the extension of the potential theory of adsorption (DA adsorption) given by Dubinin and Astakhov (1971) [Izv. AN. SSSR, Ser Khim. 5, 11-17]. To minimize the number of approximated parameters the program describes the cases where n (the parameter of the DA adsorption isotherm equation) can be different or equal to 2, but assumed ''a priori''. In this case the number of parameters is equal to 4. However, for one system only was a reliable value of the fractal dimension obtained: the instance of adsorbate-adsorbent (zeolite NaA-water). For this reason we include a supplement to the program, which allows the calculation of structural parameters for the adsorbent on the basis of a five-parameter equation (N = 5) where n is approximated. In this case all obtained fractal dimension values are reliable and these suggest that among the zeolites investigated by us the deviation from planarity decreases in the order CaA > NaA > MgA > MgY > NH4Y. Copyright (C) 1996 Elsevier Science Ltd