Efficient ethylene/ethane separation by zwitterionic deep eutectic solvent membranes

Zwitterionic deep eutectic solvent membranes (ZDESMs) hold great promise in molecular separations yet have rarely been reported. Herein, for the first time, ZDESMs are constructed by zwitterionic deep eutectic solvent (ZDES) and ethylene-transport carrier (silver salt) for ethylene/ethane separation. Experiments and simulations reveal that the ZDESMs possess structural nano-heterogeneity with discrete zwitterionic nanodomains and interconnected carrier channels, thus flexibly regulating the carrier spatial distribution as well as promoting carrier activity and stability synchronously. The ZDESMs acquires high ethylene permeability, ethylene/ethane selectivity at low carrier concentration, and long-term stability, which is superior to most of the-state-of-the-art ethylene/ethane separation membranes. The proposed ZDESMs expand the membrane family, and the nano-heterogeneity design and visualization of membrane structure will offer valuable guidance on developing advanced membranes for energy-intensive gas separations.