The influence of the pore size in Metal−Organic Frameworks in adsorption and separation of hydrogen sulphide: A molecular simulation study

Metal Organic Frameworks (MOFs) have the potential to be used as adsorbents in industrial separations. Different ligand lengths can generate MOFs with similar topology but differing pore sizes. Molecular simulations were used in this work to assess the adsorption isotherms, heats of adsorption and selectivity of H2S and CH4 in MOF UiO-66, UiO-67, and UiO-68. Detailed analysis of the distribution of molecules in the cages and the radial distribution functions suggest that the effect of the linker on the macroscopic properties is negligible at low pressures, but it becomes evident at high pressures, where adsorption far from the linker is observed in large pore materials. Based on the adsorption selection parameter, UiO-67 shows better performance in a wider range of conditions than the other materials.