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Thebinodal curves of the aqueous two-phase system (ATPS) containingpolyoxyethylene (10) lauryl ether (POELE10, C32H66O11) and three tartrate salts ((NH4)2C4H4O6, K2C4H4O6, and Na2C4H4O6) were determined at the temperatures (288.15,298.15, and 308.15) K. The binodal data in the studied systems werefit by three known equations, and a satisfactory correlation effectwas obtained. The liquid–liquid equilibrium (LLE) data forthe investigated systems were calculated by computer software in termsof the lever rule and correlated by the Othmer–Tobias and Bancroftequations, respectively. The salting-out ability of salt was discussedfrom two different perspectives: anion and cation. The analysis onthe Gibbs free energy of hydration of the ions and the binodal curvesfound that the salting-out ability of salt strengthened with the increasein absolute value of the Gibbs free energy of anion (cation) whenthe salt consisted of the same cation (or anion). The order of salting-outability of salts with the same cation was KOH < K2C4H4O6< K2CO3< K2HPO4< K3PO4, and the order of salting-out ability of salts with the same anionwas (NH4)2HPO4< K2HPO4and (NH4)2C4H4O6< K2C4H4O6< Na2C4H4O6. The effect of temperature on the phase diagram of ATPS wasstudied. It was found that it is favorable to form the ATPS when thetemperature rises and that the absolute value of the slope of thetie-line (STL) increased with the rising temperature. In the investigatedsystems, the effective excluded volume (EEV) is calculated at thedifferent temperatures, and it was found that the greater value ofEEV of the systems corresponds to the stronger phase formation ofthe ATPS. [ABSTRACT FROM AUTHOR]

Highlights: [•] The phase diagrams of POELE10-organic salts ATPSs were determined experimentally. [•] The experiential equations were used to correlate the binodal data. [•] The effect of salt on the binodal curve for the studied systems has been discussed. [•] The LLE data were correlated using the thermodynamic model. [ABSTRACT FROM AUTHOR]

Highlights: [•] The phase diagrams of acetone–sulfate ATPSs were determined experimentally. [•] The experiential equations were used to correlate the binodal data and tie-line data. [•] The effect of salt on the phase diagram for the studied systems has been discussed. [•] The effect of temperature on the phase diagram for the studied systems has been discussed. [•] The phase-separation ability of acetone has been discussed. [ABSTRACT FROM AUTHOR]

Abstract: The phase diagrams for the systems containing polyoxyethylene (10) lauryl ether (POELE10) and three salts (KOH, K2CO3 and K3PO4) have been determined experimentally. Three experiential equations were used to correlate the binodal data. The liquid–liquid equilibrium data of these systems were obtained by experimental method and calculated method using lever rule. The tie-line data were correlated by using Othmer-Tobias and Bancroft and simple Setschenow-type equations. Furthermore, the effect of salt on the binodal curve for the studied systems has been discussed by means of salting-out coefficient, effective excluded volume (EEV) and Gibbs free energy of hydration of the ions (ΔG hyd). It was found that the salts composed of anion with a higher valence are better salting-out agents than those with a lower valence. The order of salting-out abilities of salts is K3PO4 > K2CO4 > KOH for the investigated systems. Finally, the phase-separation ability of POELE10 is more powerful compared with that of other polymers and two-phase can easily form at the lower concentration, which indicates that lower cost is a remarkable advantage of POELE10–salt ATPSs. [Copyright &y& Elsevier]