Facile Synthesis of Amine‐functionalized MOFs Incorporated Polyimide MMMs with Enhanced CO2 Permselectivity

Abstract

AbstractHere a series of amine‐functionalized MOFs incorporated polyimide (PI) mixed matrix membranes (MMMs) are fabricated via an efficient method. The X‐ray diffraction (XRD) and scanning electron microscope (SEM) images clearly indicate that the metal‐organic framework (MOF) crystals are well‐retained and dispersed into the PI matrix. In addition, the resulting MMM is continuous and compact, no defects of pinhole/cracks and agglutinated MOFs can be observed from the membrane surface. This is because the hydrogen bonding between amine‐functionalized MOFs and PI can be enhanced, improving the dispersion of MOF crystals in the PI solution. More importantly, the PI/MOFs solution is further optimized by the removal of agglutinated MOFs that occur inevitably with increasing MOF loadings. The gas separation results show that the performance of MOF‐incorporated MMM has been greatly improved. For instance, compared with the pure PI film, CO2 permeability can be increased by 154.4%. Meanwhile, the selectivities of CO2/N2 and CO2/CH4 are increased by 30% and 43%, respectively. Pore structure and gas adsorption properties of MOFs clearly affect the performance of the resulting MMM.