Ionic liquid-based aqueous two-phase systems and their applications in green separation processes

As a new separation technology, ionic liquid (IL)-based aqueous two-phase systems (ATPSs) are attracting the attention of a growing number of scientists and engineers. This article reviews the significant progress that has been made in the field and highlights the possible directions of future developments. We focus on the effects of inorganic salts and ILs on the phase equilibrium of ATPSs, the microstructure of the ATPSs, and their applications in extraction and separation (e.g., small organic molecules, biochemicals, and radiological isotopes). We also address the recovery and the reuse of ILs and the work needed in future.