Self-supported flux melted glass membranes fabricated by melt quenching for gas separation

Metal-organic framework (MOF) glass is a promising candidate material for gas separation. However, MOF glasses have low porosity, which is not conducive to prepare high permeance membranes. Herein, we incorporated porous ZIF-7 into ZIF-62 glass membrane to prepare self-supported flux melted glass membranes for gas separation. The introduction of ZIF-7 not only improved pore continuity but also enhanced the porosity of the resulting glass membranes. In addition, the melting nature of ZIF-62 promotes the co-melting of ZIF-7 and thus effectively improves the interfacial compatibility. In such cases, the typical ag[(ZIF-62)0.7(ZIF-7)0.3] membrane exhibits the ideal selectivity of 98.6 for H2/CH4 and 35.3 for CO2/CH4, with H2 permeance and CO2 permeance of 120.3 and 43.1 GPU, respectively, exceeding the corresponding Robenson upper bounds. Besides, the ag[(ZIF-62)0.7(ZIF-7)0.3] membrane displays good long-term test stability for 48 h under variable pressure conditions. This work may provide a new design concept and experimental support for the construction of new MOF membranes for gas separation.