Boosting Ethane/Ethylene Separation by MOFs through the Amino-Functionalization of Pores

Adsorption technology based on ethane-selective materials is a promising alternative to energy-intensive cryogenic distillation for separating ethane (C₂ H₆ ) and ethylene (C₂ H₄ ). We employed a pore engineering strategy to tune the pore environment of a metal-organic framework (MOF) through organic functional groups and boosted the C₂ H₆ /C₂ H₄ separation of the MOF. Introduction of amino (-NH₂ ) groups into Tb-MOF-76 not only decreased pore sizes but also facilitated multiple guest-host interactions in confined pores. The NH₂ -functionalized Tb-MOF-76(NH₂ ) has increased C₂ H₆ and C₂ H₄ uptakes and C₂ H₆ /C₂ H₄ selectivity. The results of experimental and simulated transient breakthroughs reveal that Tb-MOF-76(NH₂ ) has significantly improved one-step separation performance for C₂ H₆ /C₂ H₄ mixtures with a high C₂ H₄ (>99.95 %) productivity of 17.66 L kg^-1 compared to 7.53 L kg^-1 by Tb-MOF-76, resulting from the suitable pore confinement and accessible -NH₂ groups on pore surfaces.