Computer modeling and analysis of heterogeneous structures of microporous carbonaceous materials.

The aim of this work was to study the problems connected with computer modeling and analysis of heterogeneous structures of microporous carbonaceous materials. The research was focused on the numerical properties of original mathematical models for heterogeneous multilayer adsorption on microporous carbonaceous materials presented in our earlier papers and their applicability to examination of real microporous materials. These models are aimed at drawing information on pore structure and capacity on the basis of adsorption isotherms of small molecule adsorbates. They easily fit typical adsorption data in wide relative pressure ranges. In the theory presented, adsorption of small nearly spherical molecules in irregular pores of molecular size has been considered and side adsorbate-adsorbate interactions are neglected. The molecules mentioned are located in pores by forming aggregates, the size of which is limited by the geometry of the pores. The set of adsorbate molecules, which were adsorbed mainly due to adhesive interactions with the adsorbent matter, is treated as the first layer adsorption. Joining further molecules is viewed as the second, third,... layer adsorption. The main idea of the approach to modeling microporous structure presented, consists of introducing of realistic relationships between geometrical properties of pores and adsorption energy. Special attention was focused on the analysis of the influence of the number of model parameters on identification reliability and evaluation errors of porous structure parameters. This paper gives more information on properties of the identification technique presented in our earlier papers. The five-parameter and six-parameter identification reliability is analyzed in more detail, for different values of the system parameters. In this context, the efficiency of simultaneous examination of two isotherms is also studied.