SIMULATION STUDIES OF SORPTION IN MODEL CYLINDRICAL MICROPORES

Simulations of the thermodynamic properties of simple gases in straigh t-walled cylindrical micropores are discussed. To begin, various model s used for the gas atom/pore wall interaction energy are presented. Th ese include the hard-wall cylinder, the interaction in a completely sm ooth but attractive/repulsive cylinder that is obtained by integrating over Lennard-Jones sitewise interactions, and those generated by summ ing over Lennard-Jones atoms in the solid surrounding the cylinder. Si mulations of such systems are described, particularly those carried ou t using the Grand Canonical Monte Carlo algorithm since these yield so rption isotherms as well as energies. The isotherms generally show con densation/evaporation vertical steps and, for reasonable starting cond itions, hysteresis loops. The variations in these characteristic parts of the isotherms with temperature, pore diameter and gas/pore wall in teraction strength and heterogeneity will be discussed. (C) 1998 Elsev ier Science B.V. All rights reserved.