Vacuum treated amorphous MOF mixed matrix membrane for methane/nitrogen separation

CH4/N2 separation is considered a feasible method for reducing the greenhouse effect, but its utility in industrial applications has limited by the low permselective performance. In this work, a novel method for enhancing CH4/N2 separation performance using amorphous UIO-66-NH2 with a carbonized structure (ACU) via high vacuum resistance calcination is proposed. Owing to the presence of carbonized framework that contains rich Zr4+ active sites, these vacuum-treated ACU nanoparticles showed high IAST CH4/N2 selectivity, good alkaline stability and satisfactory compatibility with polymers. Then, ACU were uniformly dispersed in polyvinyl alcohol (PVA) to obtain defect-free mixed matrix membranes (MMMs), the resulting ACU-based MMMs exhibited an enhanced CH4 separation performance. Remarkably, the PVA/ACU-120A/MPSf MMM that consisted of 80 ​wt% ACU-120A exhibited the outstanding CH4 permselectivity, achieving a CH4 permeance of 5584 GPU and CH4/N2 selectivity of 3.43.