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

Abstract

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.

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

“…Therefore, raising the temperature promotes an increase in the solubility of salts and this may result in a greater salting-out effect, which may lead to greater ease of formation of biphasic aqueous systems. A similar effect was reported by Rodrigues Barreto et al for PEG 1500, sodium sulfate, and water systems and Barreto do Nascimento et al for PEG, sodium citrate, and water. Sosa et al also verified this behavior when studying equilibrium phase systems consisting of PEG 2000, PEG 4000, and PEG 6000 and sulfate salts (manganese and copper) at temperatures of 298.15, 318.15, and 338.15 K.…”

“…The density was determined in order to calculate the mass of a phase. The density of each phase was determined in duplicate …”

Temperature Effect on the Phase Equilibrium of Polyethylene Glycol 2000 + Trilithium Citrate + Water Aqueous Two-Phase Systems at T = 288.15, 298.15, 308.15, and 318.15 K

“…Recently, Nascimento and co-workers studied the effects of temperature and pH on the liquid–liquid equilibrium of the ATPSs containing PEG 400 + Na 2 SO 4 + water . The liquid–liquid equilibrium and binodal curves of PEG 3000 + tri-potassium citrate + water at pH = 8.33, 9.60, and 10.52 were investigated by Ketabi et al Herbst and colleagues studied the phase equilibrium of the ternary system of PEG 6000 , PEG 8000 , and PEG 10000 + C 4 H 4 KNaO 6 + water at T = 283.15, 298.15, and 318.15 K. In another work, Rodrigues et al attempted to study the phase equilibrium for the ATPSs of PEG 1500 + Na 2 SO 4 + water at different temperatures (i.e., T = 293.15, 303.15, and 313.15 K) . Carvalho and co-workers introduced the ternary system of PEG 400 + Na 2 CO 3 or K 2 CO 3 + water to study the thermodynamic equilibrium, temperature, and electrolyte effects .…”

A High-Performance Guanidinium-Based Aqueous Biphasic System for Green Separation of Palladium from Acid Solution

“…Then, the content of K 3 PO 4 in the upper and lower phases was measured by the molybdenum blue method . Using the lever law, the content of each component in the upper and lower phases was calculated, namely, the line data as shown in eqs and : where the“B” and “T” superscripts denote the bottom and the top phase, respectively. By combining the obtained tether data, the tether length (TLL) and the tether slope (STL) were calculated using eqs and : …”