Nanocomposite membranes comprising covalent organic framework and polymer of intrinsic microporosity for efficient CO2 separation

The fabrication of new mixed-matrix membranes (MMMs) with superior gas permeability and selectivity are highly sought for industrial development of membrane separation technology for CO2 capture. This study reports improvement in CO2 permeability and selectivity by employing porous covalent organic framework (COF-TpPa-1). Herein, we report a novel PIM-1 doped with COF-TpPa-1 in various concentrations ranging from 0 to 10 wt% to prepare COF-TpPa-1/PIM-1 MMMs. Good compatibility between COF-TpPa-1 particles and PIM-1 matrix rendered an ideal interfacial morphology. The MMMs composed of 7 wt% COF-TpPa-1 exhibit a CO2 permeability of 6336 Barrer with an enhancement of 104 % compared to pristine sample and CO2/N2 ideal selectivity 20.1 among five tested compositions. The CO2 permeability of COF-TpPa-1 7 wt% doped membrane was 88 % more than pristine PIM-1 after 30 days aging, while CO2/N2 selectivity was well maintained, coupled with excellent anti-plasticization and mixed-gas separation properties. The overall gas separation performance of MMMs exceeds the Robeson Upper bound (2008) for CO2/N2 and O2/N2. The measured experimental permeability exhibited excellent agreement with the Singh thermal conductivity model at low loading (<5 wt%). This work provides a potential approach to fabricate PIM-1-based high performance MMMs with COF fillers for efficient CO2 separation.