Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

Castro, Beatriz; Aznar, Martı́n

doi:10.1590/s0104-66322005000300014

Cited by 17 publications

(9 citation statements)

References 23 publications

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“…Castro and Aznar 16 determined liquid−liquid equilibrium data for ATPS polyethylene glycol 8000 and magnesium sulfate or PEG 8000 and sodium sulfate at 308.15 K. These researchers correlated the experimental data of LLE with a mass-fraction-based NRTL activity coefficient model, estimating new interaction parameters.…”

Section: Introductionmentioning

confidence: 99%

Liquid–Liquid Equilibrium Data and Thermodynamic Modeling for Aqueous Two-Phase System Peg 1500 + Sodium Sulfate + Water at Different Temperatures

Barreto¹,

Castro²,

Júnior³

et al. 2019

J. Chem. Eng. Data

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Liquid–liquid equilibrium data of aqueous two phase systems (ATPS) composed of polyethylene glycol (PEG) 1500 g·mol–1 + sodium sulfate + water at T = (293.15, 303.15 and 313.15) K and p = 0.1 MPa were determined. The density of the top and bottom phases of tie-lines (TL) was determined. The universal functional activity coefficient (UNIFAC) model was correlated to the experimental tie-line data, and the root-mean-square deviations (RMSD) between experimental and calculated data were considered in the calculation. The salting-out effect was evaluated using the model of the effective volume (EEV). The temperature had no influence on the binodal curves and TL, this effect can be attributed to a small enthalpic contribution in the phase separation process. Increases in the ATPS constituents concentrations resulting in an increase in the density of the phases. The increase in temperature resulted in an increase in the salting-out effect. The highest estimated value of EEV was obtained for a system at 293.15 K. Calculated RMSD between the experimental and predicted LLE compositions for the PEG 1500 + sodium sulfate systems was 1.71%. The results of the UNIFAC model agree with the experimental tie-line values. The use of this thermodynamic model allowed the acquisition of reliable data for the system, being able to reduce the number of experiments performed.

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Section: Introductionmentioning

confidence: 99%

Liquid–Liquid Equilibrium Data and Thermodynamic Modeling for Aqueous Two-Phase System Peg 1500 + Sodium Sulfate + Water at Different Temperatures

Barreto¹,

Castro²,

Júnior³

et al. 2019

J. Chem. Eng. Data

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“…Different activity models are available in the literature for calculating such coefficients. According to the literature, the NRTL activity coefficient model based on the mass fraction is one of the most successful models for aqueous two-phase systems. − In this study, the NRTL activity coefficient model based on mass fraction was used for modeling of liquid–liquid equilibrium aqueous two phase systems . Because of the high molecular weight and consequently the lower mole fraction of polymers, the NRTL model based on mass fraction is used in this study.…”

Section: Modelingmentioning

confidence: 99%

Liquid–Liquid Equilibrium in an Aqueous Two-Phase System of Polyethylene Glycol 6000, Sodium Sulfate, Water, Glucose, and Penicillin-G: Experimental and Thermodynamic Modeling

2015

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Aqueous two-phase systems can be applied to a penicillin fermentation process to extract the produced penicillin from the fermentation broth to achieve a higher production rate. Such systems contain a polymer and a salt or two polymers. In this study, the liquid−liquid equilibrium of the quinary system of polyethylene glycol 6000, sodium sulfate, glucose, penicillin G, and water at 298.15 K is investigated. The experimental partition coefficients of glucose and penicillin-G showed the high efficiency of the present extractive fermentation processes. Using the liquid−liquid equilibrium data, the parameters of the NRTL activity model were calculated for the quinary system. The average absolute relative deviation of 0.677 % between experimental and calculated mass fractions shows that the NRTL activity model has a good ability to predict the equilibrium concentrations of the present system. In addition, a simple and accurate turbidimetric method for the measurement of penicillin G is proposed.

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“…Several works have been found that determine the liquid–liquid experimental data for polymer–salt systems. − These include work performed by Castro and Aznar who determined liquid–liquid equilibrium data for the ATPS polyethylene glycol (PEG) 8000 and magnesium sulfate or PEG 8000 and sodium sulfate at 308.15 K and by Cunha and Aznar, who determined the experimental data for the systems containing PEG 8000 + sodium sulfate and PEG 8000 + magnesium sulfate at temperatures of 298.15 and 323.15 K. In both works, the researchers correlated the experimental data of LLE with a mass-fraction-based NRTL activity coefficient model with the estimation of new interaction parameters by the simplex method.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Modeling of Aqueous Two-Phase Systems Composed of Macromolecules and Sulfate Salts at pH 2.0

et al. 2019

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Liquid–liquid equilibrium data of aqueous two-phase systems (ATPS) composed of polyethylene glycol (PEG) 8000 + sodium sulfate + water, PEG 8000 + ammonium sulfate + water, and PEG 8000 + magnesium sulfate + water at T = 298.15, 308.15, and 318.15 K and pH 2.0 were determined. The universal function activity coefficient (UNIFAC) model was correlated to the experimental tie-line data, and the root-mean-square deviations (RMSDs) between experimental and calculated data were considered in the calculation. The effects of temperature and cation type on the spinodal curves were evaluated. The salting-out effect was studied by the determination of the effective excluded volume (EEV). Rising temperature resulted in an increase in the biphasic region and tie-lines. Regarding the cation type, the phase-separation abilities followed the order Mg2+ > Na+ > (NH4)+. Increases in the overall composition of the systems resulted in increased tie-line lengths. The tie-line slope absolute values also tended to rise with increasing temperature. Increasing the ATPS constituent concentrations resulted in an increase in the phase densities. The increase in temperature resulted in an increase in the salting-out effect. The exclusion volume values increased in the following order: (NH4)+ < Na+ < Mg2+. The overall mean deviation between the experimental and correlated LLE compositions for the PEG 8000 + ammonium sulfate + water, PEG 8000 + magnesium sulfate + water, and PEG 8000 g mol–1 + sodium sulfate + water was 3.901%. The results of the UNIFAC model agree with the experimental tie-line values. This allows the use of this model to obtain reliable data for this system, thus reducing the number of experiments to be performed for a processing design.

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Liquid-liquid equilibrium of water + PEG 8000 + magnesium sulfate or sodium sulfate aqueous two-phase systems at 35°C: experimental determination and thermodynamic modeling

Cited by 17 publications

References 23 publications

Liquid–Liquid Equilibrium Data and Thermodynamic Modeling for Aqueous Two-Phase System Peg 1500 + Sodium Sulfate + Water at Different Temperatures

Liquid–Liquid Equilibrium Data and Thermodynamic Modeling for Aqueous Two-Phase System Peg 1500 + Sodium Sulfate + Water at Different Temperatures

Liquid–Liquid Equilibrium in an Aqueous Two-Phase System of Polyethylene Glycol 6000, Sodium Sulfate, Water, Glucose, and Penicillin-G: Experimental and Thermodynamic Modeling

Thermodynamic Modeling of Aqueous Two-Phase Systems Composed of Macromolecules and Sulfate Salts at pH 2.0

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