Temperature Effect on the Phase Equilibrium of Polyethylene Glycol2000+Trilithium Citrate plus Water Aqueous Two-Phase Systems at T=288.15, 298.15, 308.15, and 318.15 K

Binodal and tie-line mass fractions for ternary polyethylene glycol2000 + trilithium citrate + water aqueous two-phase systems (ATPSs) were reportedatT= 288.15, 298.15, 308.15, and 318.15 K experimentally and modeledthermodynamically. It was found that the extent of the two-phase area of the liquid-liquid equilibrium region was increased as the temperature increased. Also, binodalcurves were properly modeled with two nonlinear models, and both models havebeen successful infitting the binodal data. Furthermore, the osmotic virial, modifiednonrandom two-liquid (m-NRTL), and electrolyte-Wilson models have successfullybeen implemented in the modeling of the tie-line mass fractions. The quality offitting with the electrolyte-Wilson and specially m-NRTL models is good, and theuncertainty of the modeled data is in the range of the uncertainty of the experimentaldata. Also, the salting-out coefficient (ks) of a Setschenow-type equation was appliedas a quantitative measure of the salting-out ability. The results of the present workintroduce a green and environmentally friendly ATPS for liquid-liquid extractionand purification purposes, which can be used in the separation and purification of drugs, biomaterials, and foods

Automated summary

This study reported the binodal and tie-line mass fractions of ternary polyethylene glycol 2000 + trilithium citrate + water aqueous two-phase systems (ATPSs) experimentally and thermodynamically modeled at different temperatures. The two-phase area of the liquid-liquid equilibrium region was found to increase with temperature. Two nonlinear models were successfully used to fit the binodal curves, and the electrolyte-Wilson and m-NRTL models showed good quality of fitting for the tie-line mass fractions. The results of this study provide a green and environmentally friendly ATPS for liquid-liquid extraction and purification purposes.