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 (C 2 H 6 ) and ethylene (C 2 H 4 ). We employed a pore engineering strategy to tune the pore environment of a metal-organic framework (MOF) through organic functional groups and boosted the C 2 H 6 /C 2 H 4 separation of the MOF. Introduction of amino (-NH 2 ) groups into Tb-MOF-76 not only decreased pore sizes but also facilitated multiple guest-host interactions in confined pores. The NH 2 -functionalized Tb-MOF-76(NH 2 ) has increased C 2 H 6 and C 2 H 4 uptakes and C 2 H 6 /C 2 H 4 selectivity. The results of experimental and simulated transient breakthroughs reveal that Tb-MOF-76(NH 2 ) has significantly improved one-step separation performance for C 2 H 6 /C 2 H 4 mixtures with a high C 2 H 4 (>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 -NH 2 groups on pore surfaces.