Phase diagrams, densities and refractive indexes of poly(ethylene oxide)+organic salts+water aqueous two-phase systems: Effect of temperature, anion and molar mass

Rengifo, Andrés F.; Ferreira, Gabriel Max Dias; Ferreira, Guilherme Max Dias; Silva, Maria do Carmo Hespanhol da; Silva, Luís Henrique Mendes da

doi:10.1016/j.fluid.2015.08.002

Cited by 26 publications

(23 citation statements)

References 34 publications

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“…As expected, the ATPS with similar global compositions showed higher absolute STL values as the temperature was increased. As highlighted previously and reported elsewhere, ,,,,, the spontaneous transfer of water molecules from the macromolecule phase to the electrolyte phase is responsible for an increase in the absolute STL value. This occurs because, as the temperature increases, there is an increase in the macromolecule concentration in the MRP, concomitantly with a decrease in the electrolyte concentration in the ERP.…”

Section: Resultssupporting

confidence: 60%

“…The effect of temperature on the equilibrium compositions of the phases can also be analyzed using the slope of the tie-line (STL), which is a thermodynamic parameter calculated as follows: where C M MRP and C M ERP are the concentrations of the macromolecule in the MRP and the ERP, respectively, and C E MRP and C E ERP are the concentrations of (NH 4 ) 2 S 2 O 3 in the MRP and the ERP, respectively.…”

Section: Resultsmentioning

confidence: 99%

“…The effect of temperature on the equilibrium compositions of the phases can also be analyzed using the slope of the tie-line (STL), 43 which is a thermodynamic parameter calculated as follows:…”

Section: Methodsmentioning

confidence: 99%

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

et al. 2021

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Liquid−liquid equilibrium data were obtained for aqueous two-phase system (ATPS) composed of [poly(ethylene oxide) (PEO1500), poly(propylene oxide) (PPO425), poly(ethylene oxide) 11 −poly(propylene oxide) 17 −poly(ethylene oxide) 11 (L35), or poly(propylene oxide) 8 −poly(ethylene oxide) 22 −poly(propylene oxide) 8 (10R5)] + ammonium thiosulfate + water, at 283.2, 298.2, and 313.2 K. The consistencies of the all tie-line experimental compositions were improved by applying the Othmer− Tobias and Bancroft equations, resulting in linear correlation coefficients (R 2 ) ≥ 0.95. For all the ATPS, an increase in the temperature resulted in increases in the biphasic region and the tie-line slope, indicating that the phase separation process was entropically driven. Among the macromolecules studied, PPO425 produced the largest biphasic region, due to its greater hydrophobicity, followed by L35 ≈ 10R5 > PEO1500.

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Section: Resultssupporting

confidence: 60%

Section: Resultsmentioning

confidence: 99%

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

et al. 2021

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“…The decrease in density with increasing temperature was due to the energy supplied to the system that increased the vibration and the distance among the molecules. This behavior of the refractive index with respect to increase of the polysaccharides concentration is due to the difficulty of light to propagate through a denser solution, resulting in an increase of this property (SANTOS et al, 2012, RENGIFO et al, 2015.…”

Section: Density and Refractive Index Measurementsmentioning

confidence: 99%

Rheological behavior and physical properties of aqueous solutions of carrageenan and acacia gum

Silva

Costa

et al. 2018

Braz. J. Food Res.

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Polysaccharides are widely used as thickening, stabilizing, and gelling agents for the control of the texture, flavor, microstructure, and shelf-life of foods. This work contributes to the study of the physical properties and rheological behavior of binary and ternary solutions of carrageenan and acacia gum. Experiments were performed to determine properties such as density, refractive index, and viscosity. The results showed that those properties studied increased with increasing biopolymer concentration and decreased with increasing temperature. Experimental data were modeled to describe the combined effects of temperature and biopolymer concentration on the density, refractive index, and dynamic viscosity of these solutions. The properties were measured in the temperature range from 298.15 to 308.15 K. Suitable polynomial functions were successfully fitted to the experimental data. Classical rheological models (Bingham, power law, Casson, and Herschel-Bulkley) were tested for binary and ternary aqueous solutions containing carrageenan. Pseudoplastic behavior was observed, and the solutions were accurately modeled through a power-law model.

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“…The ATPS have many advantages in separation and purification, such as a system which is easy to be scaled up, faster mass transfer and balance, high extraction efficiency, low viscosity, little emulsion formation, no need of using volatile organic solvent, and a gentle biocompatible environment (Aziz et al 2017). The transfer of a compound from one phase to another phase in the ATPS strongly depends on the system components, as well as the intensive thermodynamic properties of the two phases in equilibrium, such as refractive index and specific mass, among others (Rengifo et al 2015;Barbosa et al 2016). In this sense, modulation of these thermodynamic properties is fundamental in order to obtain the best conditions for the purification of compounds and the creation of new systems.…”

Section: Introductionmentioning

confidence: 99%

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

Gandolfi

Gonçalves

Batista

et al. 2020

Braz. J. Chem. Eng.

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The increasing demand for safe and effective methods for the separation of biological materials combining the advantageous properties of polyethylene glycol (PEG) (1500 g mol −1 or 4000 g mol −1) and ionic liquid has led to attractive and promising applications of the new aqueous biphasic systems. In this work, the liquid-liquid extraction process with aqueous two-phase systems (ATPS) was studied for α-amylase partitioning. The phase diagrams composed of PEG (1500 or 4000) g mol −1 + 1-ethyl-3-methylimidazolium chloride + water, were determined experimentally by the turbidimetric method at different temperatures T = (293.15, 303.15, 313.15 and 323.15) K. The effect of temperature and polymer molar mass on the phase diagrams, as well as the phase densities, refractive indexes and electrical conductivity were evaluated. Subsequently, the α-amylase partitioning was performed, where the partition coefficient was determined, besides the activity and selectivity. It was found that a temperature decrease and a polymer molar mass increase favored the formation of two phases. It was also found that α-amylase showed a preference for the bottom phase composed of PEG and the systems composed of PEG 1500 presented better results. Keyword Liquid-liquid extraction • Enzyme • Partition • Amylase Abbreviations ATPS Aqueous two-phase systems PEG Polyethylene glycol [C 2 min]Cl 1-Ethyl-3-methylimidazolium chloride TLL Tie-line lengths STL Tie-line slope U One enzyme activity unit releases 1 mmol of reducing sugar per mL of extract per minute, U mL −1 ART Total reducing sugars produced in the hydrolysis step, mg mL −1 VT Total volume used in the hydrolysis, mL V c Volume of sample used in the hydrolysis, mL R t Reaction time, min BSA Bovine serum albumin K p Protein partition coefficient C t Equilibrium concentration of the total protein in the top, mg mL −1 C b Equilibrium concentration of the total protein in the bottom, mg mL −1 K e Partition coefficient for enzyme activity A t Enzyme activity in the top, mg mL −1 A b Enzyme activity in the bottom, mg mL −1 Δ tr G Gibbs free energy variation, kJ mol −1 T Absolute temperature, K R Ideal gas constant, kJ mol −1 K −1

show abstract

Phase diagrams, densities and refractive indexes of poly(ethylene oxide)+organic salts+water aqueous two-phase systems: Effect of temperature, anion and molar mass

Cited by 26 publications

References 34 publications

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

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

Rheological behavior and physical properties of aqueous solutions of carrageenan and acacia gum

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

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