UiO‐Based Mixed Matrix Membranes for Efficient CO2 Separations

Mixed matrix membranes (MMMs) containing UiO‐type metal‐organic frameworks (MOFs) have shown excellent potential for CO 2 separation processes due to their unique permeability and selectivity properties. However, while the performance of MOF‐based MMMs has been widely studied, the effect of structural defects and polymer‐filler compatibility are not yet fully understood. In this work, the CO 2 separation performance of Pebax MH1657‐based MMMs is systematically evaluated incorporating 5–20 wt% of Zr‐based MOF, including UiO‐66, UiO‐67, and two defect‐engineered UiO‐66 analogues, featuring extended linker (UiO‐66_A) or cluster (UiO‐66_F) vacancies. The structural, morphological, and thermal properties of the membranes are thoroughly characterized, with emphasis on correlating these features with gas transport performance. Single‐gas permeation experiments (CO 2 , CH 4 , H 2 ) reveal that incorporating UiO nanoparticles within the matrix consistently enhanced CO 2 permeability, reaching 145 Barrer for the 20 wt% UiO‐66_F MMM, a 216.4% increase over the neat membrane. CO 2 /CH 4 and CO 2 /H 2 selectivities also improve upon increasing MOF loadings, with UiO‐66_F achieving values of 25 and 18, respectively. This study provides insights for designing high‐performance MMMs for CO 2 separation applications, such as biogas upgrading and hydrogen purification.