Enhanced $$\text {CO}_2$$ CO 2 selectivity within the cavity of gmelinite frameworks

Abstract

We simulate the adsorption of $$\text {CO}_2$$ mixtures in three zeolitic imidazolate frameworks, namely ZIF70, ZIF80 and ZIF82. The structures display a dual pore composition with a network topology that resembles the cavity of the gmelinite zeolite. We compute the adsorption density in the pore partitions of the cavities by allocating the particle distributions of the mixture components at the individual regions of the pore network. We detect that the $$\text {CO}_2$$ adsorption and the selectivity performance, are enhanced in one group of pore channels. For ternary mixtures adsorption simulations, within the hexahedral pore channels of ZIF82, we evaluate $$\simeq 14$$ for $$\text {CO}_2$$ / $$\text {CH}_4$$ and $$\simeq 34$$ for $$\text {CO}_2$$ / $$\text {N}_2$$ selectivity at 1 bar and 298 K, which are among the highest reported selectivity values at such conditions, for the class of porous frameworks, including the metal organic frameworks (MOFs).