Perspective on ionic liquids and ionic liquid membranes

Ionic liquids can be used in various morphologies and configurations as membrane systems including supported liquid membranes, membrane contactors, and mixed matrix membranes. In each case, the negligible vapor pressure can lead to a highly stable structure since the ionic liquid is non-volatile. This perspective is meant to provide some background information on the use of ionic liquids in membrane systems and a discussion of future opportunities for this technology. Ionic liquids with different physical properties can be synthesized in a wide range of structures. In addition, this platform provides an opportunity to “tune” the physical/chemical properties such as density, viscosity, hydrophobicity, and chemical affinity for specific applications. The use of ionic liquids in membrane systems should see continued growth in the future.