Robust metal–organic framework with abundant large electronegative sites for removal of CO2 from a ternary C2H2/C2H4/CO2 mixture

• Published in: Inorganic chemistry frontiers 2022-09, Vol.9 (19), p.5064-5071
• Main Authors: Cheng, Xiong, Yan-Hong, Xiao, Liu, Qingyou, Chen, Ling, Chun-Ting, He, Qing-Yan, Liu, Yu-Ling, Wang
• Format: Article
• Language: English
• Subjects: Carbon dioxide; Electronegativity; Fluorine; Gas mixtures; Inorganic chemistry; Metal-organic frameworks; Oxygen atoms; Porous materials; Separation; Water stability
• ISSN: 2052-1545; 2052-1553
• DOI: 10.1039/d2qi01175a

Separation of ternary gas mixtures is challenging and has rarely been achieved with a single porous solid material. Herein a trinuclear iron(iii) based metal–organic framework (MOF) with high water stability, {[Fe3(μ3-O)(DFBDC)3(TPT)](OH)}n (JXNU-14) (DFBDC2− = 2,5-difluoroterephthalate and TPT = 2,4,6-tri(4-pyridinyl)-1,3,5-triazine), is applied for the removal of CO2 from a ternary C2H2/C2H4/CO2 mixture. The trigonal bipyramidal cavities and cylindrical cavities decorated with highly electronegative fluorine and oxygen atoms and abundant π rings in JXNU-14 offer stronger affinity for C2H2 and C2H4 than for CO2, resulting in the high-performance separation of a ternary equimolar mixture of C2H2, C2H4, and CO2, which is demonstrated by pure-component gas adsorption isotherms and actual column breakthrough experiments. The much stronger binding of C2H2 and C2H4 as compared to CO2 was further revealed by computational simulations. This work provides a useful strategy for the construction of MOFs possessing high-density electronegative sites for the efficient removal of CO2 from a ternary C2H2/C2H4/CO2 mixture.