Centro de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa , 1749-016 Lisboa, Portugal.
ACS Appl Mater Interfaces. 2014 Aug 13;6(15):12093-9. doi: 10.1021/am502686g. Epub 2014 Jul 16.
The separation of ethylene from ethane is one of the most energy-intensive single distillations practiced. This separation could be alternatively made by an adsorption process if the adsorbent would preferentially adsorb ethane over ethylene. Materials that exhibit this feature are scarce. Here, we report the case of a metal-organic framework, the IRMOF-8, for which the adsorption isotherms of ethane and ethylene were measured at 298 and 318 K up to pressures of 1000 kPa. Separation of ethane/ethylene mixtures was achieved in flow experiments using a IRMOF-8 filled column. The interaction of gas molecules with the surface of IRMOF-8 was explored using density functional theory (DFT) methods. We show both experimentally and computationally that, as a result of the difference in the interaction energies of ethane and ethylene in IRMOF-8, this material presents the preferential adsorption of ethane over ethylene. The results obtained in this study suggest that MOFs with ligands exhibiting high aromaticity character are prone to adsorb ethane preferably over ethylene.
从乙烷中分离乙烯是实践中最耗能的单一蒸馏操作之一。如果吸附剂优先吸附乙烷而不是乙烯，则可以通过吸附过程来替代这种分离。表现出这种特性的材料很少。在这里，我们报告了一种金属有机骨架（IRMOF-8）的情况，在 298 和 318 K 下测量了其在高达 1000 kPa 压力下的乙烷和乙烯的吸附等温线。使用填充有 IRMOF-8 的柱子在流动实验中实现了乙烷/乙烯混合物的分离。使用密度泛函理论（DFT）方法研究了气体分子与 IRMOF-8 表面的相互作用。我们通过实验和计算表明，由于乙烷和乙烯在 IRMOF-8 中的相互作用能的差异，这种材料表现出对乙烷的优先吸附而不是乙烯。本研究的结果表明，具有高芳香性特征的配体的 MOFs 更容易优先吸附乙烷而不是乙烯。
