One-step purification of ethylene from ethane/ethylene mixtures by a stable vanadium-based metal-organic framework

The efficient separation of ethylene (C 2 H 4 ) from ethane/ethylene (C 2 H 6 /C 2 H 4 ) mixtures, achieved via a single-step selective adsorption process, represents a promising yet challenging goal. Notably, the pursuit of adsorbents that combine high adsorption capacity with low adsorption heat is paramount, as these attributes directly correlate with superior separation efficiency and minimized regeneration energy. In this study, we present the selective adsorption of C 2 H 6 over C 2 H 4 by a V-MOF (V-TBAPy), constructed from [V( μ 2 -O)O 4 ] n secondary building units. The pore surface of V-TBAPy is characterized by a high density of aromatic rings and oxygen atoms, which facilitates targeted adsorption of C 2 H 6 through C-H···π and C-H···O interactions. V-TBAPy adsorbs up to 102.6 cm 3 /g of C 2 H 6 at 298 K and 1 bar, with a selectivity of 1.66 for an equimolar C 2 H 6 /C 2 H 4 binary mixture. Importantly, the adsorption heat for C 2 H 6 on V-TBAPy is as low as 22.7 kJ/mol, enabling energy-efficient regeneration. Breakthrough experiments have confirmed the efficacy of V-TBAPy in achieving one-step purification of C 2 H 6 /C 2 H 4 mixtures in conditions mimicking industrial settings.