Enhancing polyimide-based mixed matrix membranes performance for CO2 separation containing PAF-1 and p-DCX

Dongyun Wu, Rujing Hou, Chunhai Yi, Stefan J.D. Smith, Jiawen Fu, Derrick Ng, Cara M. Doherty, Roger J. Mulder, Zongli Xie, Matthew R. Hill

Research output: Contribution to journalArticleResearchpeer-review


Gradual permeability loss due to physical aging and the trade-off relationship between permeability and selectivity has largely hindered the advancement of membrane technology. In our prior works, porous aromatic framework (PAF-1) and poly-dichloroxylene (p-DCX) incorporated mixed matrix membranes (MMMs) have shown excellent anti-aging properties, achieved through polymer side chains adsorbing within PAF-1 or p-DCX pores. Advantageously, antiaging behaviour was usually also accompanied by enhanced membrane permeability due to the high porosity of the PAF-1 or p-DCX additive. However, these works mostly focused on polymers with moderate selectivities, such as polymers of intrinsic microporosity (PIM-1) and poly-trimethylsilyl-propyne (PTMSP). In this work, we investigated the anti-aging properties of PAF-1 and p-DCX in a highly selective polyimide (PI) polymer and demonstrated its potential for industrial CO2 separation. As anticipated, PI membranes demonstrated a slower CO2 aging rate with the addition of PAF-1 and p-DCX, for both single gases under low-pressure and mixed gas under high-pressure measurements. Additionally, the CO2 permeability was significantly enhanced, and consequently the mixed-gas performance of the composite PI-based membranes surpassed 2008 Upper Bounds for both CO2/N2 and CO2/CH4 separation.

Original languageEnglish
Article number118677
Number of pages11
JournalSeparation and Purification Technology
Publication statusPublished - 1 Aug 2021


  • Anti-aging property
  • Gas separation
  • Mixed matrix membranes
  • Organic porous additives
  • Polyimide

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