Abstract Air separation is one of the most challenging separations because of the very similar molecular dimensions of gas molecules. We used a high-throughput computational screening approach to identify the upper performance limits of metal organic framework (MOF) membranes and MOF/polymer mixed matrix membranes (MMMs) for O2/N2 separation. Gas permeabilities and selectivities were calculated for 5629 MOF membranes and 78,806 different types of MOF/polymer MMMs, which represent the largest number of MOF-based membranes studied to date for air separation. Our results showed that many MOF membranes exceed the upper bound established for polymer membranes due to their high permeabilities and/or selectivities. The maximum achievable O2 permeability and O2/N2 selectivity of MOF/polymer MMMs were computed as 2710.8 Barrer and 19.8, respectively. Results revealed that MOF/polymer MMMs can outperform MMMs composed of traditional fillers, such as zeolites, in terms of O2 permeability and O2/N2 selectivity. The impacts of purity of air mixture and the structural flexibility of MOFs on the gas separation performances of MMMs were also discussed. These results provide molecular-level insights into adsorption and diffusion behaviors of O2 and N2 in MOF membranes in addition to presenting structure-performance relations of MOFs that can lead to high-performance membranes and fillers for MMMs.

中文翻译：

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使用计算筛选探索 MOF/聚合物 MMM 用于 O2/N2 分离的性能限制

摘要 空气分离是最具挑战性的分离之一，因为气体分子的分子尺寸非常相似。我们使用高通量计算筛选方法来确定金属有机框架 (MOF) 膜和 MOF/聚合物混合基质膜 (MMM) 用于 O2/N2 分离的性能上限。计算了 5629 种 MOF 膜和 78,806 种不同类型的 MOF/聚合物 MMM 的气体渗透率和选择性，这是迄今为止研究的用于空气分离的基于 MOF 的膜的数量最多。我们的结果表明，由于其高渗透性和/或选择性，许多 MOF 膜超过了为聚合物膜建立的上限。MOF/聚合物 MMM 的最大可实现 O2 渗透率和 O2/N2 选择性分别计算为 2710.8 Barrer 和 19.8。结果表明，在 O2 渗透性和 O2/N2 选择性方面，MOF/聚合物 MMM 的性能优于由传统填料（如沸石）组成的 MMM。还讨论了空气混合物的纯度和 MOF 的结构灵活性对 MMM 气体分离性能的影响。这些结果提供了对 O2 和 N2 在 MOF 膜中的吸附和扩散行为的分子水平的见解，此外还展示了 MOF 的结构 - 性能关系，可导致 MMM 的高性能膜和填料。