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. 2016 Feb 4:6:20276.
doi: 10.1038/srep20276.

Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

Helena Passos  1 , Andreia Luís  1 , João A P Coutinho  1 , Mara G Freire  1
Affiliations

Thermoreversible (Ionic-Liquid-Based) Aqueous Biphasic Systems

Helena Passos et al. Sci Rep. .

Abstract

The ability to induce reversible phase transitions between homogeneous solutions and biphasic liquid-liquid systems, at pre-defined and suitable operating temperatures, is of crucial relevance in the design of separation processes. Ionic-liquid-based aqueous biphasic systems (IL-based ABS) have demonstrated superior performance as alternative extraction platforms, and their thermoreversible behaviour is here disclosed by the use of protic ILs. The applicability of the temperature-induced phase switching is further demonstrated with the complete extraction of two value-added proteins, achieved in a single-step. It is shown that these temperature-induced mono(bi)phasic systems are significantly more versatile than classical liquid-liquid systems which are constrained by their critical temperatures. IL-based ABS allow to work in a wide range of temperatures and compositions which can be tailored to fit the requirements of a given separation process.

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Figures

Figure 1
Figure 1. 3D representation of the temperature effect in the IL-based ABS.
Ternary phase diagrams for (a) [N1120][C1CO2] + PPG + H2O and (b) [N11[2(N11)]0][C1CO2] + PPG + H2O systems at different temperatures.
Figure 2
Figure 2. Schematic representation of PIL-based ABS thermoreversibility.
Binodal curve of the ternary system composed of [N11[2(N11)]0]Cl + PPG + H2O. Green circles: 25 °C; blue diamond: 45 °C; orange square: initial mixture composition.
Figure 3
Figure 3. Partitioning of cytochrome c and azocasein at three different concentrations (1, 2 and 3 g·L−1) in PIL-based ABS formed at 45 °C.
Extraction efficiency of (a) cytochrome c (EECyt%) (b) azocasein (EEAzo%). The extraction efficiency data are presented in Supplementary Table 7.
See this image and copyright information in PMC

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