Investigating adsorption- and diffusion selectivity of CO2 and CH4 from air on zeolitic imidazolate Framework-78 using molecular simulations

摘要

The adsorption and diffusion of N-2, O-2 representing air, in ternary mixtures with CO2 or CH4, on Zeolitic Imidazolate Framework-78 are investigated by Gibbs ensemble Monte Carlo (GEMC) simulations for adsorption and by molecular dynamics (MD) simulations for diffusion. The adsorption and diffusion data are used for determining the membrane selectivities. N-2/O-2 ratios are found to be nearly the same in the gas and the adsorbed phase. At 228 K and low concentrations the CO2/N-2 adsorption selectivity is found to attain values of as large as 140, further increasing with decreasing CO2 concentration.