Advancements in Gas Separation for Energy Applications: Exploring the Potential of Polymer Membranes with Intrinsic Microporosity (PIM).

Membrane-based Polymers of Intrinsic Microporosity (PIMs) are promising candidates for energy-efficient industrial gas separations, especially for the separation of carbon dioxide over methane (CO 2 /CH 4 ) and carbon dioxide over nitrogen (CO 2 /N 2 ) for natural gas/biogas upgrading and carbon capture from flue gases, respectively. Compared to other separation techniques, membrane separations offer potential energy and cost savings. Ultra-permeable PIM-based polymers are currently leading the trade-off between permeability and selectivity for gas separations, particularly in CO 2 /CH 4 and CO 2 /N 2 . These membranes show a significant improvement in performance and fall within a linear correlation on benchmark Robeson plots, which are parallel to, but significantly above, the CO 2 /CH 4 and CO 2 /N 2 Robeson upper bounds. This improvement is expected to enhance the credibility of polymer membranes for CO 2 separations and stimulate further research in polymer science and applied engineering to develop membrane systems for these CO 2 separations, which are critical to energy and environmental sustainability. This review aims to highlight the state-of-the-art strategies employed to enhance gas separation performances in PIM-based membranes while also mitigating aging effects. These strategies include chemical post-modification, crosslinking, UV and thermal treatment of PIM, as well as the incorporation of nanofillers in the polymeric matrix.