Preparation and performance of porous framework reinforced mixed-matrix membranes for CH₄/N₂ separation

This study addresses the efficient utilization of coalbed methane, a methane-rich unconventional natural gas, by developing a novel membrane separation technology. A reinforced mixed matrix membrane was created using electrospinning to combine polyvinylidene fluoride (PVDF) with a block polymer (SBS) and metal-organic framework material (Ni-MOF-74). Notably, the PM20 membrane, incorporating 20% Ni-MOF-74, demonstrated exceptional mechanical and separation properties. It exhibited a tensile strength of 29.5 MPa, which is approximately 50% higher than that of pure SBS resin membranes. In terms of CH₄ permeation, the PM20 membrane achieved a remarkable rate of 97 Barrer and a CH₄/N₂ selectivity of 4.03, significantly surpassing other membrane materials. For CH₄-N₂ binary gas mixtures, the membrane also exhibits high CH₄ permeability and selectivity. This advancement in membrane technology not only enhances the capture and utilization rate of methane in low-concentration coalbed gas but also contributes to the broader goals of sustainable energy use and greenhouse gas emission reduction. The study's findings hold significant promise for the future of unconventional energy sources and offer new directions in coalbed gas treatment and methane enrichment technologies.