Mixed matrix metal–organic framework membranes for efficient CO2/N2 separation under humid conditions

Mixed matrix metal–organic framework (MOF) membranes show excellent application prospects in gas separation. However, their stability in various practical application scenarios is poor, especially under humid conditions. Herein, we encapsulated a hydrophobic ionic liquid (IL) into the cavity of MOFs, which effectively mitigated the competition between H 2 O and CO 2 in humid gas mixtures, leading to stable and high-performance gas separation. For this reason, the resulting membranes using polymer of intrinsic miroporosity-1 (PIM-1) as a polymer matrix show good CO 2 /N 2 separation performance and long-term test stability under humid environment. In particular, the 20 wt% IL-UiO/PIM-1 shows a high permeability of 13,778 Barrer and competitive CO 2 /N 2 separation factor of ~35.2, transcending the latest upper bound. Besides, the according membrane module exhibits slightly decreased CO 2 permeability and selectivity, promoting the application of self-supporting membranes. This work provides a reliable strategy for the rational design of MOF-based hybrid membranes under extreme conditions.