Importance of pore length and geometry in the adsorption/desorption process: a molecular simulation study

Discrete potentials can describe properly the liquid vapour boundary that is necessary to model the adsorption of gas molecules in mesoporous systems with computer simulations. Although there are some works in this subject, the simulations are still highly time-consuming. Here we show that an efficient alternative is to use the three-dimensional Ising model, which allows one to model large systems, with geometries as complex as required that accurately represent the liquid vapour boundary. In particular, we report molecular simulations of cylindrical pores of two different geometries, using a discrete potential. The effect of the length of the pore in the hysteresis loop for a finite pore and infinite one is studied in detail. Lastly, we compare our predictions with experimental results and find excellent agreement between the area of the hysteresis loop predicted for the finite pore and that found in adsorption/desorption experiments.