Development of materials with excellent separation performances remains an ongoing challenge in methane/nitrogen (CH₄/N₂) separation science. Herein, a facile and effective method for enhancing CH₄ uptake, binding, and CH₄/N₂ selectivity using the surface-carbonized and stiffened zeolitic imidazolate framework-8 (CSZ) via high-vacuum-resistance calcination (HVRC) was demonstrated. Such vacuum-treated CSZ nanoparticles, with carbonized structures that contain Zn-rich sites, high stability, and satisfactory compatibility with polymers, were then uniformly mixed with the strong basic polymer polyvinylamine (PVAm) to obtain large-area mixed-matrix membranes (1120 cm², which is ca. 2 pieces of A4-size paper). Owing to the presence of Zn-rich sites and amino groups, CH₄ molecules were bound more readily to CSZ and PVAm than N₂, as confirmed by gas adsorption isotherms and DFT calculations. The obtained MMM modules (ca. 2000 cm²) exhibited outstanding CH₄ separation performances at 85 wt% CSZ loading, achieving a CH₄ permeance of 7600 GPU and CH₄/N₂ selectivity of 4.35.

中文翻译：

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大面积真空处理的 ZIF-8 混合基质膜用于高效的甲烷/氮气分离

开发具有优异分离性能的材料仍然是甲烷/氮（CH ₄ /N ₂）分离科学中的一项持续挑战。在此，展示了一种通过高真空电阻煅烧 (HVRC) 使用表面碳化和硬化的沸石咪唑酸酯骨架 8 (CSZ) 来提高 CH ₄吸收、结合和 CH ₄ /N _{2选择性的简便有效的方法。}这种真空处理的 CSZ 纳米粒子具有碳化结构，含有富锌位点，稳定性高，与聚合物相容性好，然后与强碱性聚合物聚乙烯胺 (PVAm) 均匀混合，得到大面积混合基质膜 (1120厘米²，大约是。2 张 A4 尺寸的纸）。由于存在富锌位点和氨基，CH ₄分子比 N ₂更容易与 CSZ 和 PVAm 结合，气体吸附等温线和 DFT 计算证实了这一点。获得的 MMM 模块（约 2000 cm ²）在 85 wt% CSZ 负载下表现出出色的 CH ₄分离性能，实现了7600 GPU的 CH _{4渗透率和 4.35 的 CH 4} /N ₂选择性。