Diffusion of Water and Carbon Dioxide and Mixtures Thereof in Mg-MOF-74
journal contributionposted on 04.12.2018, 00:00 by S. Bendt, Y. Dong, F. J. Keil
Self-diffusion coefficients for CO2, H2O, and mixtures thereof in Mg-MOF-74 have been determined using molecular simulations. The crystal structure was modeled in a rigid and flexible manner with the intent to identify the impact of the flexibility of the framework on the diffusivity. The results show that especially at low loadings the mobility of the molecules is enhanced in flexible lattices because of a small difference in adsorption energy and the enlarged equilibrium distance to the main adsorption sites. In mixtures the flexibility has the same influence; however, because of the presence of the secondary species, water is predominantly located in the close proximity of the magnesium-ion which effectively leads to a segregation effect from the more freely moving CO2.