Monte Carlo Simulations of Water Adsorption Isotherms in Silicalite and Dealuminated Zeolite Y

Abstract

The affinity that adsorbents have for water can influence their effectiveness in organics removal from drinking water due to competitive adsorption. The extent of the affinity of microporous zeolites for water is determined, in part, by AlO4(-) tetrahedral sites (T-sites) in the crystal lattice and lattice defects in the form of silanol nests. In this study, water adsorption isotherms in silicalite and in dealuminated zeolite Y (DAY) were simulated using the Compass force-field. The results show that the simulations can predict the shape of water adsorption isotherms and predict adsorption levels comparable to literature results. Moreover, simulations revealed that the results are influenced significantly by the presence of AlO4(-) T-sites. The results confirm the capacity of the Compass force-field to predict water sorption properties in silicalite and in DAY.

Competitive adsorption and selectivity of benzene and water vapor on the microporous metal organic frameworks (HKUST-1)

“…These hydrophobic sites will weaken the interactions between water and the HKUST-1, resulting in lower isosteric heat than that of water adsorption on the copper sites and these carboxylic groups. Moreover, the DH S values of water vapor adsorption for the HKUST-1 are lower than that for Al-ZSM-5 (22.0 kJ/mol, pore size: 5.5 Å) and zeolite Y (17.1 kJ/mol, pore size: 7.4 Å) [29] under comparable conditions. The possible explanation lies in the fact that the larger pore size of the HKUST-1 with less hydrophilic property will reduce the interaction of water molecules with the HKUST-1 in comparison with the Al-ZSM-5 and zeolite Y.…”

Molecular simulations of water in hydrophobic microporous solids

“…Molecular simulations is a well suitable to gain a profound understanding of dynamical, structural or thermodynamic properties of polar and non polar fluids confined in nanopores (Auerbach et al 2003;Bussai et al, 2001Bussai et al, , 2002Bussai et al, , 2003Demontis et al 2003;Fleys et al 2004;Desbiens et al 2005;Douguet et al 1996;Fleys and Thompson 2005;Ramachandran et al 2006;Puibasset and Pellenq 2003a).…”

Molecular Scale Modeling of Membrane Water Treatment Processes

“…However, there have been a number of simulations investigating the behavior of water within siliceous zeolites [55][56][57][58][59][60][61][62]. The most popular zeolites for simulation are silicalite or dealuminated zeolite Y (DAY).…”

“…Consequently, when considering the diffusion of water within zeolites, the use of QM techniques is not appropriate because of the limited timescale that is accessible. Although unable to provide information about dynamic properties, the Monte Carlo (MC) techniques, especially the Grand Canonical MC, can provide valuable information that is difficult to obtain through other methods, such as adsorption isotherms [59][60][61]71].…”