Selectively Trapping Ethane from Ethylene on Metal–Organic Framework MIL-53(Al)-FA

Developing ethane-selective adsorbents is critical for efficient separation and purification of ethylene from the cracked gas, which is a great challenge in the petrochemical industry. Herein, a facile and robust MOF, MIL-53(Al)-FA, was prepared and investigated for its ethylene/ethane separation properties. Single-component ethylene and ethane isotherms of MIL-53(Al)-FA showed a higher ethane capacity than that of ethylene, with an ethane uptake of 3.7 mmol/g at 100 kPa and 1.2 mmol/g at 6.25 kPa (the proportion of ethane in the cracked gas) under 308 K. In addition, its IAST-predicted selectivity for an equimolar ethylene/ethane mixture was 1.9 at 100 kPa, while a dynamic selectivity of 1.8 could be achieved from breakthrough experiments. The mechanism for preferential adsorption of ethane over ethylene on MIL-53(Al)-FA was further revealed by molecular simulation. The average energies between the adsorbates and the sample were −10 kcal/mol and −8 kcal/mol for ethane and ethylene, respectively, resultin...