Simulation of adsorption, diffusion, and permeability of water and ethanol in NaA zeolite membranes

Grand canonical ensemble Monte Carlo (GCMC) and equilibrium molecular dynamics (EMD) methods were employed to simulate the adsorption and diffusion of water and ethanol in NaA zeolite from 298 K to 423 K. Competitive adsorption was found for the water/ethanol mixture adsorbed in NaA zeolite. The molecular diffusion in zeolite channels is affected more strongly by operating temperature than adsorption. Permeation fluxes of pure water and ethanol through a NaA zeolite membrane were predicted based on the simulated data of adsorption and diffusion. The contributions of adsorption and diffusion to the permeation flux were evaluated. The increased diffusivity at the elevated temperature is the main contributor to the improvement of the water permeation flux.