Metal–organic frameworks (MOFs) with robust and three-dimensional pore structures are promising molecular sieve fillers in mixed-matrix membranes (MMMs) for carbon capture. Herein, high-valency metal-carboxylate-coordinated yttrium-MOF Y-abtc (abtc = 3,3′,5,5′-azobenzene-tetracarboxylate) with strong coordination bonds was incorporated into the Pebax-1657 polymer matrix to explore their CO₂/N₂ separation performance. The optimized N-Y-abtc@Pebax-15% MMMs showed simultaneously improved CO₂ permeability (79%) and CO₂/N₂ selectivity (94%) relative to the pristine Pebax membrane, exceeding the 2008 upper bound and approaching the 2019 upper bound. This was ascribed to the synergistic effect of a suitable window aperture, ultrahigh CO₂ adsorption capacity (64.77 cm³/g), high ideal adsorption solution theory selectivity (IAST) (254) for CO₂/N₂ (50/50, v/v) in nanosized Y-abtc (N-Y-abtc), and the newly created molecular sieve channels in N-Y-abtc@Pebax MMMs. Meanwhile, the rigid framework structure and hydrothermal stability of N-Y-abtc provide good pressure resistance and long-term stability for the N-Y-abtc@Pebax-15% MMMs. The successful property translation from the molecular sieve of N-Y-abtc adsorbents into membranes implied its potential application for flue gas treatment and may also shed light on the design of MOF-based MMMs for other challenging separations.

中文翻译：

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在混合基质膜中构建分子筛通道以有效分离二氧化碳

具有坚固的三维孔隙结构的金属有机框架（MOF）是用于碳捕获的混合基质膜（MMM）中很有前途的分子筛填料。在此，将具有强配位键的高价金属羧酸盐配位钇-MOF Y-abtc（abtc = 3,3',5,5'-偶氮苯四羧酸盐）引入Pebax-1657聚合物基质中，以探索其CO2 ₂ /N ₂分离性能。优化后的 NY-abtc@Pebax-15% MMM 相对于原始 Pebax 膜同时表现出改善的 CO ₂渗透性 (79%) 和 CO ₂ /N ₂选择性 (94%)，超过 2008 年上限并接近 2019 年上限。这归因于合适的窗口孔径、超高CO ₂吸附容量(64.77 cm ^{3 /g)、CO} ₂ /N ₂ (50/50, v ) 的高理想吸附溶液理论选择性(IAST) (254)的协同效应。 /v) 纳米 Y-abtc (NY-abtc) 中，以及 NY-abtc@Pebax MMM 中新创建的分子筛通道。同时，NY-abtc的刚性框架结构和水热稳定性为NY-abtc@Pebax-15% MMM提供了良好的耐压性和长期稳定性。 NY-abtc 吸附剂的分子筛特性成功转化为膜，这意味着其在烟气处理方面的潜在应用，也可能为基于 MOF 的 MMM 设计用于其他具有挑战性的分离提供启示。