Deep Eutectic Solvent Membranes Designed by the Same-Anion Strategy for Highly Efficient Ethylene/Ethane Separation

Abstract

Deep eutectic solvents (DESs) are a new generation of designer and green solvents and offer tremendous opportunities for separation science; however, the construction of high-permeance DES membranes (DESMs) with excellent stability for ethylene/ethane separation is still a challenge. In this study, by the same-anion strategy, a series of DESs with the CF3SO3– anion were designed for the first time and then combined with an ethylene transport carrier (AgCF3SO3) for the construction of DESMs for highly efficient ethylene/ethane separation. DESMs were facilely fabricated by impregnating the as-designed DESs and AgCF3SO3 carrier into the commercial poly(vinylidene fluoride) membrane, where the DESs not only exhibited good compatibility with AgCF3SO3 but also stimulated high carrier activity and afforded good carrier stability. The resultant DESMs displayed high ethylene permeability, ethylene/ethane selectivity, and excellent stability, especially the maximum permeability and selectivity reached up to 910 barrer and 83, thus being superior to most of the state-of-the-art ethylene/ethane separation membranes. Finally, the separation mechanism was revealed, and the regulation of hydrogen-bond and coordinative interactions within DESMs by the rational structural design accounted for excellent performances. This work extends the DES library and will accelerate the prosperity of DESMs for energy-intensive gas separations.