High SF6 selectivities and capacities in isostructural metal-organic frameworks with proper pore sizes and highly dense unsaturated metal sites

A series of isostructural M-MOF-74 materials (M = Mg, Co, and Zn) with proper pore sizes (11 Å) and highly dense unsaturated metal sites have been examined for the selective adsorption of SF6 over nitrogen. Mg-MOF-74 and Co-MOF-74 show the largest SF6 uptake reported for any adsorbent, including MOFs, at ambient temperature and pressure. Zn-MOF-74 exhibits one of the highest SF6/N2 reported selectivities. These materials were evaluated for two possible SF6 separation processes using five adsorbent criteria, revealing that these materials are promising adsorptive materials for SF6/N2 separation.