Utilization of cationic microporous metal-organic framework for efficient Xe/Kr separation

The separation of xenon/krypton(Xe/Kr)mixtures plays a vital role in the industrial process of manufacturing high-purity xenon.Compared with energy-intensive cryogenic distillation,porous materials based on physical adsorption are very promising in the low-cost and energy-saving separation processes.Herein,we show that a cationic metal-organic framework(named as FJU-55)exhibits highly efficient Xe/Kr separation performance,which can be attributable to its uniform three-dimensional(3D)interconnection channels and the electro-positive features as the host framework.Moreover,FJU-55 demonstrates good Xe adsorption capacity of 1.41 mmol/g and excellent Xe/Kr selectivity of 10(298 K and 100 kPa),together with a high Qst value of 39.4 kJ/mol at low coverage area.The superior Xe/Kr separation performance of FJU-55 was further confirmed by the dynamic breakthrough experiments.Results obtained via molecular modeling studies have revealed that the suitable pore size and abundant accessible aromatic ligands in FJU-55 could offer strong multiple C–H∙∙∙Xe interactions,which play a collaborative role in this challenging gas separation task.