Deportment Tuning of Polymeric Gas Separation Membranes: ZIF-L/PES Nanocomposite

The novel mixed-matrix membranes that are designed to simultaneously enhance gas permeability, selectivity and filler-polymer compatibility are highly sought for industrial deployment of membrane technology for large-scale CO2 capture. Carbon capture performance of polymeric membranes is significantly improved by doping mesoporous zeolitic imidazolate framework (ZIF-L) nanoflakes into polymer matrix. ZIF-L is prepared via cold-synthesis method and is incorporated in varied concentrations into polyethersulfone (PES) matrix to improve CO2 permeability and CO2/N2 selectivity of resultant membranes. Morphological and structural characteristics of synthesized ZIF-L nanoparticles are characterized by SEM and XRD, respectively. Flat-sheet membranes prepared through phase inversion method are characterized to evaluating their structural, crystalline, morphological and thermal properties by FTIR, XRD, SEM and TGA techniques. Characterizations indicated homogeneous dispersal of nanofillers along strong interactions between ZIF-L to polymer chains which enhanced the carbon capture efficiency of membranes and measured as CO2 permeability and CO2/N2 selectivity by gas permeation test under different feed-side upstream pressures. Both filler concentration and feed pressure led to enhanced permeation through membranes in comparison with pristine PES membrane, and CO2 permeability increased from 3.7 to 24.9 Barrer for 3% ZIF-L nanoflakes doping while CO2/N2 selectivity is increased from 2.2 to 30.6 for 2% filler loading at 1.5 bar pressure. Raising feed pressure from 1.5 to 6 bar is resulted into CO2 permeability increment from 24.9 to 27.2 Barrer for 3% filler loading. Therefore, these designed membranes have efficacy for permeability for CO2 and N2 in industrial applications and environmental solutions.