Influence of the molecular weight of polymer, temperature and pH on phase diagrams of poly (ethylene glycol) + di-potassium tartrate aqueous two-phase systems

Aqueous two-phase system (polyethylene glycol + ionic liquid) for extraction of α-amylase: phase diagrams, systems characterization and partition study

“…2), it can be observed that PEG 4000 (of higher molar mass) presented a larger two-phase region. A similar behavior was observed by Barani et al (2018) in the conventional ATPS formed by PEG (1500 or 6000) and salt (di-potassium tartrate). Rodríguez et al (2009) found that polymers with higher molecular weights are less soluble in ionic liquid and are more easily separated from the aqueous medium, due to decreased PEG solubility in water with increased polymer molar mass.…”

“…ATPS are formed by two phases coexisting in equilibrium due to the dissolution, at appropriate concentrations, of solute pairs in water (Freire et al 2012;Wu et al 2017). They are formed by two immiscible or partially miscible aqueous phases which can be obtained by the addition of two aqueous solutions of two natural or synthetic hydrophilic polymers, of a polymer solution and a saline solution, an ionic liquid and a salt or polymer, a surfactant and polymer or salt or a low molecular weight alcohol and a salt (Rodríguez et al 2009;Pereira et al 2013;Liu et al 2015;Hekayati et al 2016;Fan et al 2017; Barani et al 2018;Junqueira et al 2018;Oliveira et al 2018;Escudelo et al 2019;Penido et al 2019).…”

Phase Equilibria of Aqueous Two-Phase Systems of PEG with Sulfate Salt: Effects of pH, Temperature, Type of Cation, and Polymer Molecular Weight

“…It is important to note that temperature control is essential during the whole experimental procedure. The experimental procedure has been described in detail in previous studies, ,− and all devices used in this study were essentially the same as in our previous work . Stock solutions of PEGs (50 and 80 wt %), zinc sulfate (30 wt %), and ammonium sulfate (40 wt %) were prepared.…”

Liquid–Liquid Equilibrium Data of Macromolecule + Ammonium Thiosulfate + Water Ternary Systems at 283.2, 298.2, and 313.2 K

“…Different electrolytes have been used in the literature to obtain ATPS composed of macromolecules, such as sulfates, 17−21 phosphates, 22,23 citrates, 24,25 thiocyanates, 26 and tartrates. 23,25,27,28 However, as far as we know, liquid−liquid equilibrium data made up of ammonium thiosulfate are not related in the literature. Two studies reporting the use of sodium thiosulfate to obtain ATPS with PEO with a molar mass of 1500, 4000, or 6000 g mol −1 .…”

“…The acquisition of liquid–liquid equilibrium data for new green ATPS with greater hydrophobicity, investigating the effect of the hydrophobic/hydrophilic balance of the macromolecule on the formation of the systems, can assist in elucidating the mechanisms that lead to their formation to expand the potential applications in the field of separation/purification. Different electrolytes have been used in the literature to obtain ATPS composed of macromolecules, such as sulfates, − phosphates, , citrates, , thiocyanates, and tartrates. ,,, However, as far as we know, liquid–liquid equilibrium data made up of ammonium thiosulfate are not related in the literature. Two studies reporting the use of sodium thiosulfate to obtain ATPS with PEO with a molar mass of 1500, 4000, or 6000 g mol –1 . , The use of ammonium thiosulfate ((NH 4 ) 2 S 2 O 3 ) as the electrolyte is an excellent strategy for the separation of analytes, mainly metal ions, because, compared to many other salts, it is inexpensive and nontoxic and has reducing and complexing characteristics.…”