Insights into Water Adsorption in Potassium-Exchanged X-type Faujasite Zeolite: Molecular Simulation and Experiment

In the present study, we have combined several atomic-scale computational techniques [static lattice optimization, density functional theory (DFT), canonical Monte Carlo (MC), and Gibbs ensemble MC (GEMC)] with experiment in order to describe adsorption of water potassium-exchanged X-type faujasite. Indeed, by applying DFT calculations, evidenced a strongly heterogeneous adsorbent surface classified preferential sites at zero loading for molecules. The sodalite cage was identified as location. Moreover, GEMC technique, successfully simulated isotherm K–X zeolite. Finally, through simulation, described microscopic mechanisms within zeolite various uptakes, ranging from low (8 H2O/unit cell) saturation (240 cell). We that loading, cages host major part adsorbed molecules, while increasing hydration ratio, molecules locate more supercages. At saturation, each accommodates than three on average, whereas nearly 90% are located any supercages coordinate preferentially potassium cations crystallographic site III (or III?) rather II. Cations II start interacting only uptakes superior 80 H2O molecules/unit cell, once all occupied least one molecule.