Engineered O 2 -Selective Nanotraps in Mixed Matrix Membranes for High-Performance Air Separation

作者：Shuang Wang, Zhengqing Zhang, Zixian Qin, Mao Ye, Yi Yang, Yuxiu Sun, Zhihua Qiao, Zhi Wang · 发表于：ACS Sustainable Chemistry & Engineering · 年份：2025 · DOI：10.1021/acssuschemeng.5c09001 · 被引用次数：2 · 研究领域：Membrane Separation and Gas Transport、Membrane Separation Technologies、Membrane-based Ion Separation Techniques

Efficient air separation remains a significant challenge due to the nearly identical physicochemical properties of N 2 and O 2 . In this study, we address this challenge by designing O 2 -selective nanotraps within the cavities of MOF-808 dispersed in polymer matrices through the targeted integration of indole moieties. Carboxylic acid-functionalized indole molecules are anchored to Zr sites via ligand exchange, creating confined environments with enhanced O 2 affinity. The higher electronegativity of O 2 (3.44 vs 3.04 for N 2 ) drives its preferential adsorption over N 2 . Building on this mechanism, we fabricated a mixed matrix membrane (MMM S ) that exhibits an O 2 -selective permeation, achieving an optimal O 2 permeability of 402.2 Barrer and an O 2 /N 2 selectivity of 7.1 under simulated ambient air conditions (21% O 2 /79% N 2 ). This performance is attributed to the targeted enrichment of the O 2 molecules within the MOF cavities. In-situ Fourier-transform infrared (FTIR) analysis and density functional theory (DFT) calculations both experimentally and theoretically validate the critical role of host–guest interactions in mediating the O 2 /N 2 separation. By leveraging the modular design of organic molecules, this work establishes a promising paradigm for advancing MMMs that utilize interaction-driven selectivity for complex gas separation processes.