Calculation Procedure for the Surface Tension of Vapor–Liquid Menisci in Porous Bodies

A calculation procedure of the surface tension (ST) of vapor–liquid menisci in porous bodies based on the microscopic lattice gas model (LGM) is presented. Ideas of this model are used to describe a two-level structural model of mesoporous bodies and to calculate adsorbate distributions in a given structure of an adsorbent. The supramolecular level of the model is presented as a granule/grain of a porous material with the set distribution function of connected pores of different sizes and types. At the molecular level, a LGM ensures an equally accurate description of adsorbate molecular distributions in the coexisting vapor and liquid phases and at their interface. ST is calculated through a local excess of the free energy that is generated by vapor–liquid interfaces inside the pores. Calculated STs characterize the spatial distribution of mobile phases in porous systems. The capability to obtain local information about ST, which reflects the size and energy features of porous systems, significantly exceeds the capabilities of the thermodynamic approach.