Molecular Simulation of Propane Adsorption in FAU Zeolites

The purpose of this study is to investigate propane adsorption capacity in sodium and calcium form of faujasite (FAU)-type zeolites X and Y by performing Monte Carlo simulations in the grand-canonical ensemble (GCMC). Our results have shown that the nonframework cation number density and the interaction potentials between propane molecules and the nonframework cations are very important factors for influencing propane adsorption in FAU zeolites. For a given ratio of Si/Al, the adsorption of propane in both sodium and calcium FAU increases with the increasing nonframework cation number density, suggesting that an increase in the number of cations produces extra adsorption sites and leads to a higher amount of adsorption. For a given nonframework cation number density, the higher ratio of Si/Al allows the higher adsorption capacity due to the reduced charge density, i.e., the fewer calcium cations, but more sodium cations making the interaction energy more negative and consequently higher affinity between, propane and the nonframework cations.