Liquid–Liquid Equilibrium of Aqueous Two-Phase Systems Composed of Nonionic Surfactant (Triton X-100, Triton X-165, or Triton X-305) and Choline Chloride

Abstract

The study of aqueous two-phase systems (ATPSs) formed by ionic liquids based on the choline cation and nonionic surfactants has received attention in recent years because of the biodegradability and nontoxicity of their components. In this work, liquid–liquid equilibrium data were obtained for ATPSs composed of Triton X (Triton X-100, Triton X-165, and Triton X-305), choline chloride, and water, at 298.15, 313.15, and 328.15 K. In general, these systems presented a top phase rich in choline chloride and a bottom phase rich in surfactant, although the phenomenon of phase inversion was observed for a specific thermodynamic condition of the system formed by Triton X-165. It was observed that increase of the temperature led to an increase of the biphasic region, indicating an endothermic phase separation process. In addition, higher hydrophobicity of the surfactant increased its ability to promote phase segregation (the biphasic region increased in the following order: Triton X-100 > Triton X-165 > Triton X-305). The reliability of the equilibrium data was confirmed using the Othmer–Tobias and Bancroft correlations.

Liquid–Liquid Equilibrium of Aqueous Two-Phase Systems Formed by Nonionic Surfactants (Triton X-100, Triton X-165, or Triton X-305), Salts (NaNO3 or KNO3), and Water at Different Temperatures

“…The turbidimetric curves exhibit “L-type” profiles, as is usually observed in ATPSs formed by surfactants and electrolytes, ,, and the data at 298.2 K are similar to those obtained by Khayati et al It is noteworthy that in the turbidimetric curve for the system formed by TX-100, NaNO 3 , and water at 328.2 K, there was a range in which the surfactant concentration slightly increased as the salt concentration also increased. This behavior has been reported by Silva et al for systems formed by TX-100, choline chloride, and water.…”

“…Regarding nonionic surfactants commonly used to obtain ATPSs, those from the Triton X series have been the most investigated. ,,− The interest in these surfactants for analytical applications using ATPSs can be associated with some of their properties, especially as follows: (i) they have a high solubility in water, enabling the preparation of ATPSs in a large range of compositions, including biphasic systems with high tie-line lengths (TLLs) that could improve extraction efficiency; and (ii) they are liquid at room temperature, facilitating their handling in the preparation of ATPSs. − Triton X surfactants have been combined with polymers, , ionic liquids, ,, and salts , to create ATPSs. However, the reported data concerning the liquid–liquid equilibrium in these different combinations is still limited to a complete understanding of the molecular aspects associated with the separation process.…”

Liquid–Liquid Equilibrium Data of Various Micellar Aqueous Two-Phase Systems for the Extraction of Rhodamine B and Hexavalent Chromium

“…The addition of salt to surfactant solutions imparts the phase separation at lower temperatures, enabling the system for the extraction application at lower temperatures. Recent works include the generation of binodal curve for surfactant (Triton X-100)�ionic liquid ATPS with choline cation 16 and cholinium dihydrogen phosphate. 17 Also, the equilibrium studies with different nonionic surfactants Tergitol 15 23 and Triton X-114 24 have been reported.…”

Anthocyanin Partition in Aqueous Two‐Phase Systems Based on Isopropanol and Sodium/Ammonium Sulfate

“…Traditionally, ATPS are based on polymer-salt or polymerpolymer [16,17] mixtures, which leads to spontaneous twophase formation at appropriate concentrations. In recent years, however, other pairs of phase-forming agents have been studied such as alcohol-sugar [18], surfactant-polymer [1], surfactant-ionic liquid [19,20], salt-ionic liquid [14,21], and shortlength chain alcohol-salt [22][23][24]. Systems composed of alcohol-inorganic salt have several advantages over traditional ATPS, among which are lower cost, interfacial tension and viscosity, better resolution, higher yield, simpler scale-up, ecofriendliness [12,14], easy recovery of the target biomolecule from the alcohol-rich phase, and possibility of recycling the phase-forming components [11,25].…”