An indium-based ethane-trapping MOF for efficient selective separation of C2H6/C2H4 mixture

The purification of ethylene (C 2 H 4 ) from the cracking gas ethane/ethylene mixture (1:15, v / v ) is a typical energy-intensive process in the chemical industry. As an alternative, adsorptive separation with much lower energy consumption and operational cost has attracted escalating attention. In this work, we reported an interesting C 2 H 6 -trapping adsorbent, In-soc-MOF-1, an indium-based metal-organic framework exhibiting the preferential adsorption of C 2 H 6 over C 2 H 4 . Single-component adsorption isotherms showed that the C 2 H 6 adsorption capacities were higher than those of C 2 H 4 under measured temperatures (288, 298 and 308 K). For example, the uptakes of C 2 H 6 and C 2 H 4 were 4.04 and 3.72 mmol/g at 298 K and 100 kPa, respectively. The calculated IAST selectivity of C 2 H 6 /C 2 H 4 (1:15) on In-soc-MOF-1 was in the range of 1.4–4.8. Moreover, the dynamic separation performance of In-soc-MOF-1 toward the C 2 H 6 /C 2 H 4 binary mixture was evaluated by the breakthrough experiments, the result of which suggests that In-soc-MOF-1 could achieve efficient separation by trapping the impurity C 2 H 6 molecules out of the C 2 H 6 /C 2 H 4 binary mixture. Notably, In-soc-MOF-1 not only showed good water and moisture stability but also exhibited excellent recyclability, where negligible decrease in C 2 H 6 adsorption capacity was observed during five cycles of adsorption-desorption tests. These properties suggest that In-soc-MOF-1, as a C 2 H 6 -trapping adsorbent, could be considered as a potential candidate in the practical application of separating the cracking gas mixture.