Physisorption-driven removal of acetylene (C₂H₂) from ethylene (C₂H₄) is a promising pathway to produce polymer-grade C₂H₄. However, advances have been constrained by the compromise needed between selectivity and adsorption capacity. Herein, physisorption-mediated separation of trace C₂H₂ from C₂H₄ was carefully examined over pillared metal–organic frameworks (MOFs) through a combination of experiments and theoretical calculations, disclosing that concurrent enhancement of C₂H₂ uptake capacity and selectivity under low C₂H₂ pressure conditions was observed due to pore-environment engineering of MOFs. Compared to its counterparts including −H and −NH₂, the −CH₃-functionalized MOF, named ZU-901, could achieve the highest separation performance, delivering a C₂H₂ uptake capacity of 0.57 mmol·g^–1 at 0.01 bar and an ideal adsorbed solution theory selectivity of ca. 83 for a mixture of C₂H₂ and C₂H₄ with a volumetric ratio of 1:99 (1% C₂H₂/99% C₂H₄ (V/V)) at 298 K. Their efficiency for C₂H₂/C₂H₄ separation, especially in the low-pressure range, was demonstrated by dynamical breakthrough experiments, where the breakthrough time reached 220 min·g^–1 under a 1% C₂H₂/99% C₂H₄ (V/V) flow rate of 2 mL min^–1. Theoretical calculations pointed out that ZU-901 with ligand functionalization has the optimized pore environment and aperture size, boosting the selectively accommodated C₂H₂ via the synergetic effect of O···H(HC≡) and H(H₂pzdc, −CH₃)···C(C≡) interactions between C₂H₂ molecules and frameworks. This work presents an example of pore-environment optimization to break the selectivity-capacity trade-off toward the purification of C₂H₄ by the removal of C₂H₂.

中文翻译：

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促进乙烯脱乙炔的柱状金属有机骨架孔隙环境工程

物理吸附驱动从乙烯 ( C ₂ H ₄ ) 中去除乙炔 (C ₂ H ₂ ) 是生产聚合物级 C ₂ H ₄的一种有前景的途径。然而，选择性和吸附能力之间所需的折衷限制了进展。在此，通过实验和理论计算相结合，在柱状金属有机框架（MOF）上仔细检查了痕量 C ₂ H ₂与 C ₂ H _{4的物理吸附介导分离，揭示了 C 2} H ₂吸收能力的同时增强和由于MOFs的孔隙环境工程，观察到低C ₂ H _{2压力条件下的选择性。与包含-H和-NH 2}的同类产品相比，-CH ₃功能化MOF（名为ZU-901）可以实现最高的分离性能，在0.01 bar下的C ₂ H ₂吸收能力为0.57 mmol·g ^–1理想的吸附溶液理论选择性约为。对于体积比为 1:99 (1% C ₂ H ₂ /99% C ₂ H _{4 (V/V)) 的 C 2} H ₂和 C ₂ H ₄混合物，在 298 K 下的效率为83。通过动态突破实验证明了₂ H ₂ /C ₂ H ₄分离，特别是在低压范围内，在1% C ₂ H ₂ /99% C ₂ H下突破时间达到220 min·g ^–1 ₄ (V/V) 流速为 2 mL min ^–1。理论计算指出，配体功能化的ZU-901具有优化的孔环境和孔径尺寸，_通过O ·H(HC^)和H(H 2 _pzdc , − CH ₃ )···C(C≡) C ₂ H ₂分子与骨架之间的相互作用。这项工作提出了一个孔隙环境优化的例子，以打破通过去除 C ₂ H _{2纯化 C 2} H ₄的选择性-容量权衡。