Fluorocarboxylic Acid-Modified MOF-808 with Enhanced Acetylene Adsorption Capacity and C2H2/C2H4 Separation Performance

Graphical We prepared a series of fluorinated MOFs through the post- synthesis modification of the classic Zr-based MOF-808. The fluorinated alkane pores within MOFs can enhance the forces between the framework and C 2 H 2 , therefore, the difference in the adsorption capacity to C 2 H 2 and C 2 H 4 making it possible to effectively separate the C 2 H 2 /C 2 H 4 mixture at room temperature. The separation of ethylene (C 2 H 4 ) and acetylene (C 2 H 2 ) is challenging due to their similar molecular dimensions and boiling points, making conventional methods like cryogenic distillation and solvent extraction inefficient and environmentally harmful. Fluorinated metal-organic frameworks (MOFs) have been proven to be an effective material for the separation of C 2 H 4 and C 2 H 2. However, their direct synthesis is relatively expensive and challenging. In this study, we report a facile post-synthetic modification strategy to introduce fluorinated alkane pores into a zirconium-based MOF, MOF-808. The construction of fluorine-containing pores within the MOFs prefers adsorption for C 2 H 2 attributed to the interaction between the fluorine atoms and C 2 H 2 . This series of fluorinated MOFs demonstrates potential for gas separation processes, with the highest separation ratio reaching 2.67 (1 : 99) at 298 K. Breakthrough experiments for C 2 H 2 /C 2 H 4 mixtures confirmed that fluorinated MOF is capable of separating C 2 H 2 /C 2 H 4 , making it a potential candidate for industrial application. Moreover, the simplicity of the post-synthetic modification method suggests a viable strategy for the synthesis of fluorinated MOFs.