Recent advances in supported ionic liquid membrane technology

Novel processes based on supported liquid membranes have been proposed as effective methods for the selective separation of different chemical species in dilute streams, such as metal ions, organic compounds or biologically important compounds and gas mixtures. However, the industrial use of supported liquid membranes based on conventional liquids is limited by their relative instability and short lifetime. The use of ionic liquids as a liquid membrane phase could overcome these inconveniences due to their negligible vapour pressure and the possibility of minimizing their solubility in the surrounding phases by adequate selection of the cation and anion. The possibility of designing suitable ionic liquids for specific separation problems has also opened up new potential fields of industrial application of supported ionic liquid membranes. In this review an overview is given of recent advances in supported membranes based on ionic liquids, including issues such as methods of preparation, transport mechanisms, configurations, stability, fields of application and process intensification using supported ionic liquid membranes.

► Research areas in SILM technology include separation of organic compounds, mixed gases and ions and analytical and electrochemical applications.
► The stability, permeability and selectivity of SILMs could be improved by changing the anion and cation composition of the ionic liquid used as liquid phase.
► The emergence of a considerable number of new ILs will open up new fields of application of SILMs.