Multifunctional ternary deep eutectic solvent-based membranes for the cost-effective ethylene/ethane separation

Membrane technology is a forward-looking approach for gas separation, while the implementation of membrane with high performance for ethylene/ethane separation still challenges the world. Herein, a multifunctional ternary deep eutectic solvent (DES)-based membrane was constructed for the cost-effective ethylene/ethane separation. The incorporation of a sweetener (Al(NO3)(3)) with the AgNO3/methylacetamide (NMA) mixture to form a ternary DES not only significantly promoted the ethylene/ethane selectivity but also enhanced the longterm stability of resultant membranes, which killed two birds with one stone. Various spectroscopic characterization and quantum mechanical calculations revealed that the complexing interaction between Agthorn and NMA and the complexing interaction between Al3+ and NO3- weakened the electrostatic interaction between Agthorn and NO3, and improved the interaction energy between ethylene molecule and Agthorn carrier. By the synergy effects of two different complexing interactions, the ternary DES-based membranes exhibited high ethylene permeability, ethylene/ethane selectivity and stability, outperforming majority of the previously published data. Therefore, the membranes proved the grand potential for ethylene/ethane separation, and this work will shed light on the design of multifunctional liquid membranes for precise molecular separation.