Customizing Metal‐Organic Frameworks by Lego‐Brick Strategy for One‐Step Purification of Ethylene from a Quaternary Gas Mixture

Abstract

AbstractOne‐step purification of ethylene (C2H4) from a quaternary gas mixture of C2H6/C2H4/C2H2/CO2 by adsorption is a promising separation process, yet developing adsorbents that synergistically capture various gas impurities remains challenging. Herein, a Lego‐brick strategy is proposed to customize pore chemistry in a unified framework material. The ethane‐selective MOF platform is further modified with customized binding sites to specifically adsorb acetylene and carbon dioxide, thus one‐step purification of C2H4 with high productivity of polymer‐grade product (134 mol kg−1) is achieved on the assembly of porous coordination polymer‐2,5‐furandicarboxylic acid (PCP‐FDCA) and PCP‐5‐aminoisophthalic acid (IPA‐NH2). Computational studies verify that the low‐polarity surface of this MOFs‐based platform provides a delicate environment for C2H6 recognition, and the specific binding sites (FDCA and IPA‐NH2) exhibit favorable trapping of C2H2 and CO2 via CHδ+···Oδ− and Cδ+···Nδ− electrostatic interactions, respectively. The proposed Lego‐brick strategy to customize binding sites within the MOFs structure provides new ideas for the design of adsorbents for compounded separation tasks.