Creating uniform pores for xenon/ krypton and acetylene/ethylene separation on a strontium-based metal-organic framework

• Published in: Journal of solid state chemistry 2020-08, Vol.288, p.121337, Article 121337
• Main Authors: Xiong, Jianbo, Li, Ailin, Fan, Yaling, Xu, Zhenzhen, Feng, Han, Gao, Qiang, Fan, Qiangwen, He, Yan, Gao, Zhi, Luo, Feng
• Format: Article
• Language: English
• Subjects: Acetylene/ethylene separation; Density functional theory; Metal-organic framework; Xenon/ krypton separation
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1016/j.jssc.2020.121337

Industrial separations of xenon/krypton and acetylene/ethylene systems are challenging and energy-intensive processes. Exploring new porous material for their separation is of great significance. We reported here a strontium based thermostable metal-organic framework [Sr4(TCPE4−)2(DMF)4(H2O)4]n·solvent (1) (TCPE ​= ​tetrakis(4-carboxyphenyl)ethylene) with quadrangular pores possess diameter of 3.60 ​Å (type-1 pore). Heating the MOF 1 in vacuum can drive the coordinated solvent molecules away and open the type-2 pores with diameter of 4.40 ​Å. This contributes to xenon and acetylene absorption with Xe/Kr selectivity of 6.93 (Xe/Kr ​= ​20:80) and acetylene/ethylene selectivity of 1.75 (acetylene/ethylene ​= ​1:99). The density functional theory (DFT) calculations revealed the interactions between the MOF skeleton and the absorbed Xe atom. Exploring new porous material for xenon/krypton and acetylene/ethylene separations is of great significance. Here, we present a strontium based thermostable metal-organic framework [Sr4(TCPE4−)2(DMF)4(H2O)4]n·solvent (1) (TCPE ​= ​tetrakis(4-carboxyphenyl)ethylene) with quadrangular pores possess diameter of 3.60 ​Å (type-I pore). Heating the MOF 1 in vacuum can drive the coordinated solvent molecules away and open the type-II pores with diameter of 4.40 ​Å, which contribute to the adsorption and separation of xenon/krypton and acetylene/ethylene systems. Density functional theory (DFT) calculations was performed to disclose the interactions between the MOF skeleton and the absorbed Xe atom. [Display omitted] •A strategy of creating new uniform pores through removing the coordinated solvent molecules was presented.•Adsorption and separation of xenon/ krypton and acetylene/ethylene systems were studied.•MOF 1 shows excellent thermostability with thermogravimetric curve sustained to 550 °C.