Functional Materials Design, Discovery & Development Research Group (FMD3) Advanced Membranes & Porous Materials Center Division of Physical Sciences and Engineering King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Kingdom of Saudi Arabia.
Chem Soc Rev. 2017 Jun 6;46(11):3402-3430. doi: 10.1039/c7cs00153c.
The separation of related molecules with similar physical/chemical properties is of prime industrial importance and practically entails a substantial energy penalty, typically necessitating the operation of energy-demanding low temperature fractional distillation techniques. Certainly research efforts, in academia and industry alike, are ongoing with the main aim to develop advanced functional porous materials to be adopted as adsorbents for the effective and energy-efficient separation of various important commodities. Of special interest is the subclass of metal-organic frameworks (MOFs) with pore aperture sizes below 5-7 Å, namely ultra-microporous MOFs, which in contrast to conventional zeolites and activated carbons show great prospects for addressing key challenges in separations pertaining to energy and environmental sustainability, specifically materials for carbon capture and separation of olefin/paraffin, acetylene/ethylene, linear/branched alkanes, xenon/krypton, etc. In this tutorial review we discuss the latest developments in ultra-microporous MOF adsorbents and their use as separating agents via thermodynamics and/or kinetics and molecular sieving. Appreciably, we provide insights into the distinct microscopic mechanisms governing the resultant separation performances, and suggest a plausible correlation between the inherent structural features/topology of MOFs and the associated gas/vapour separation performance.
相关分子的物理/化学性质相似，因此将其分离具有重要的工业意义，但实际操作中会产生巨大的能量损耗，通常需要采用低温分馏等耗能技术。学术界和工业界都在持续进行研究，主要目标是开发先进的功能多孔材料，用作有效且节能的各种重要商品的吸附剂。特别值得关注的是孔径尺寸小于 5-7Å 的金属-有机骨架（MOF）亚类，即超微孔 MOF。与传统沸石和活性炭相比，超微孔 MOF 在解决与能源和环境可持续性相关的分离方面的关键挑战方面具有广阔的前景，具体涉及碳捕集以及烯烃/烷烃、乙炔/乙烯、直链/支链烷烃、氙/氪等的分离材料。在本综述中，我们讨论了超微孔 MOF 吸附剂的最新发展及其作为通过热力学和/或动力学和分子筛用作分离剂的用途。值得注意的是，我们深入了解了控制分离性能的微观机制，并提出了 MOF 的固有结构特征/拓扑结构与相关气体/蒸气分离性能之间的合理相关性。
