Facilitated transport mixed matrix membranes incorporated with amine functionalized MCM-41 for enhanced gas separation properties

Facilitated transport mixed matrix membranes (FT-MMMs) were fabricated by incorporating polyethylenimine functionalized ordered mesoporous silica (PEI-MCM-41) into poly(ether-block-amide) (Pebax® MH 1657). The polyethylenimine both in the pore channels and on the surface of MCM-41 rendered abundant amine carriers to facilitate the transport of CO2 through reversible reaction and simultaneously improved the filler–polymer interface compatibility. The membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), tensile test, dynamic mechanical analysis (DMA), and X-ray diffraction (XRD). The results indicated that incorporation of PEI-MCM-41 generated stronger interfacial interactions and resulted in higher polymer chain rigidification at the filler–polymer interface compared with unmodified MCM-41. The as-prepared FT-MMMs showed increased gas permeability and selectivity, and the highest ideal selectivities for CO2/CH4 and CO2/N2 were 41 and 102 (at a CO2 permeability of 1521 Barrer), respectively. Compared to the membranes doped with pristine MCM-41, the permeability, the ideal CO2/CH4 selectivity and the ideal CO2/N2 selectivity of the PEI-MCM-41-doped membranes were increased by 102.3%, 115.8% and 96.1%, respectively, at 20 wt% filler loading and surpassed the 2008 Robeson upper bound line.