Preparation of a self-supported zeolite glass composite membrane for CO₂/CH₄ separation

The low porosity of metal-organic framework glass makes it difficult to prepare membranes with high permeability. To solve this problem, we fabricated a series of self-supported zeolite glass composite membranes with different 4A zeolite loadings using the abundant pore structure of the zeolite. The 4A zeolite embedded in the zeolite glass composite membrane preserved the ligand bonds and chemical structure. The self-supported zeolite glass composite membranes exhibited good interfacial compatibility. More importantly, the incorporation of the 4A zeolite significantly improved the CO₂ adsorption capacity of the pure a_gZIF-62 membranes. In addition, gas separation performance measurements showed that the (a_gZIF-62)_0.7(4A)_0.3 membrane had a permeability of 13,329 Barrer for pure CO₂ and an ideal selectivity of 31.7 for CO₂/CH₄, which exceeded Robeson's upper bound. The (a_gZIF-62)_0.7(4A)_0.3 membrane exhibited good operational stability in the variable pressure test and 48 h long-term continuous test. This study provides a method for preparing zeolite glass composite membranes.