Efficient SF6/N2 separation at high pressures using a zirconium-based mesoporous metal–organic framework

Adsorptive separation of SF6/N2 mixtures is an important issue since SF6 is a significant greenhouse gas. Although separation performances should be evaluated under high pressure conditions to find an efficient adsorbent candidate for pressure swing adsorption (PSA) processes, no studies on metal–organic frameworks (MOFs) have focused on SF6/N2 separation at high pressures above 1 bar. In this study, we evaluated the potential of three hydrothermally stable adsorbents, including two MOFs (UiO-66 and UiO-67) and zeolite-13X, for SF6/N2 separation under normal PSA operation pressures (∼10 bar). Interestingly, UiO-67 with a high surface area and large pore size exhibited very high SF6/N2 selectivity (30∼37) at 10 bar as well as a significantly large SF6 working capacity (5.94 mmol g−1) between 10 bar and 1 bar. Moreover, UiO-67 showed facile regeneration at the ambient temperature as well as good cyclic adsorption and desorption behavior during 20 cycles. These results show that UiO-67 is a potential adsorbent for adsorptive SF6/N2 separation.