使用 2D-COF 支持的离子液体膜对 CO2/N2 分离的分子洞察,Physical Chemistry Chemical Physics

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使用 2D-COF 支持的离子液体膜对 CO2/N2 分离的分子洞察
Physical Chemistry Chemical Physics ( IF 2.9 ) Pub Date : 2022-09-23 , DOI: 10.1039/d2cp03044f
Kuiyuan Zhang ₁ , Lixia Zhou ₂ , Zichang Wang ₁ , Haiyang Li ₁ , Youguo Yan ₁ , Jun Zhang ₁

Affiliation

共价有机骨架 (COF) 因其均匀且高密度的亚纳米级孔隙而显示出在气体分离中的巨大应用潜力。然而，大多数COF孔径较大，并且与气体对（3-6 Å）存在不匹配，并且空间位阻在气体选择性中不起作用。在这项工作中，制备了一种用于CO ₂ /N ₂分离的COF（NUS-2）负载离子液体膜（COF-SILM）。使用分子动力学模拟研究分离性能。超高CO ₂渗透率高达2.317 × 10 ⁶ GPU，与N ₂相比，获得了更好的CO _2选择性. _{详细讨论了超高渗透性和CO 2}选择性的物理机制。超薄膜、高密度孔隙和高跨膜驱动力是CO ₂超高渗透性的原因。离子液体（IL）对CO ₂和N ₂的不同吸附能力，以及允许CO ₂通过和抑制N ₂通过的门控效应，有助于提高CO _2对N₂的选择性. 此外，还讨论了 COF 层数和 IL 厚度对气体分离性能的影响。这项工作为COF-SILM的气体分离机理提供了分子水平的理解，模拟结果显示了一种潜在的优秀CO ₂分离膜可用于未来的应用。

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Molecular insight into CO2/N2 separation using a 2D-COF supported ionic liquid membrane

The covalent organic framework (COF) shows great potential for use in gas separation because of its uniform and high-density sub-nanometer sized pores. However, most of the COF pore sizes are large, and there are mismatches with the gas pairs (3–6 Å), and the steric hindrance cannot work in gas selectivity. In this work, one type of COF (NUS-2) supported ionic liquid membrane (COF-SILM) was prepared for use in CO₂/N₂ separation. The separation performance was investigated using molecular dynamics simulation. There was an ultrahigh CO₂ permeability up to 2.317 × 10⁶ GPU, and a better CO₂ selectivity was obtained when compared to that of N₂. The physical mechanism of ultrahigh permeability and CO₂ selectivity are discussed in detail. The ultrathin membrane, high-density pores and high transmembrane driving force are responsible for the ultrahigh permeability of CO₂. The different adsorption capabilities of ionic liquid (IL) for CO₂ and N₂, as well as a gating effect, which allows CO₂ passage and inhibits N₂ passage, contribute to the better CO₂ selectivity over N₂. Moreover, the effects of the COF layer number and IL thickness on gas separation performance are also discussed. This work provides a molecular level understanding of the gas separation mechanism of COF-SILM, and the simulation results show one potential outstanding CO₂ separation membrane for future applications.

更新日期：2022-09-23

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