Monte Carlo Simulations of Adsorption of Non-polar and Polar Molecules in Zeolite<i>X</i>

Abstract

Abstract Grand canonical Monte Carlo simulations have been performed for single-gas adsorption of Lennard-Jones molecules with point multipole moments in zeolite cavities of type X. Fluid-solid electrostatic interactions are taken into account. Adsorption isotherms, isosteric heats and structural properties have been calculated for Xe, CH4, CO2, C2H4 and i-C4H10 and compared with experiment. The results reveal the importance of adsorbate-adsorbate interactions for sorption in faujasite. The interaction of the quadrupole moment of CO2 with the electric field generated by the zeolite ions constitutes more than half of the total energy of adsorption. Density and energy distributions show that the cavity is either a relatively homogeneous surface or a highly heterogeneous one, depending on the molecular characteristics of the adsorbed gas and the type, position and charge of the zeolite cations.