Density Functional Theory Calculations of Henry's constant for N_2, O_2 and Ar molecules in Ca-A and Ca-LSX Zeolites

摘要

Zeolites are widely used in industry as gas-separation adsorbents or heterogeneous catalysts. An understanding of the adsorption properties of these materials (adsorption isotherms, Henry constants and isosteric heats) is vital to efficient separation process design and operation. In this paper we propose a method for the prediction of Henry constants and isosteric heats at zero coverage. By embedding a quantum mechanics calculation (QM) in a classical molecular mechanics (MM) model of the environment, the hybrid QM/MM scheme attempts to incorporate environmental effects at an atomistic level, including influences as accessibility hindrance, electrostatic perturbations and dielectric screening.