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 (C2H6) and ethylene (C2H4). We employed a pore engineering strategy to tune the pore environment of a metal-organic framework (MOF) through organic functional groups and boosted the C2H6/C2H4 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 C2H6 and C2H4 uptakes and C2H6/C2H4 selectivity. The results of experimental and simulated transient breakthroughs reveal that Tb-MOF-76(NH2) has significantly improved one-step separation performance for C2H6/C2H4 mixtures with a high C2H4 (>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.