Aqueous two-phase systems formed by different phase-forming components : equilibrium diagrams and dye partitioning study.

Abstract

The present work aimed to characterize new aqueous two-phase system (ATPS) formed by Triton X-100 þ Li2SO4 þ H2O, polyvinylpyrrolidone Mw ¼ 10,000 g mol -1 (PVP10k) þ Li2SO4 þ H2O, and Triton X-100 þ PVP10k þ H2O, evaluating the effect of temperature and the nature of ATPS-forming components on the biphasic region. ATPSs formed by Li2SO4 showed greater efficiency in phase segregation compared to ATPSs formed by polymer/surfactant, with the biphasic area of ATPSs formed by Triton X-100 greater than that formed by PVP10k. For all ATPSs studied, temperature had a small effect on the biphasic region. The data were fitted with good correlation using the Merchuk equation for the binodal curves and OthmereTobias and Bancroft equations for the tie-lines. The partitioning studies show that there is an uneven distribution of Reactive Yellow HE-4R dye between the phases for all ATPSs and, with a tie-line length increase, there is an increase in the tendency of the dye to partition to the phase in which it interacts most strongly. For ATPSs formed by Li2SO4, the dye is preferentially transferred to the macromolecule-rich phase (top phase), whereas for the system formed by polymer/surfactant, the dye is partitioned to the PVP10k enriched phase (bottom phase). The present work aimed to characterize new aqueous two-phase system (ATPS) formed by Triton X -100 þ Li2SO4 þ H2O, polyvinylpyrrolidone Mw ¼ 10,000 g mol 1 (PVP10k) þ Li2SO4 þ H2O, and Triton X 100 þ PVP10k þ H2O, evaluating the effect of temperature and the nature of ATPS-forming components on the biphasic region. ATPSs formed by Li2SO4 showed greater efficiency in phase segregation compared to ATPSs formed by polymer/surfactant, with the biphasic area of ATPSs formed by Triton X-100 greater than that formed by PVP10k. For all ATPSs studied, temperature had a small effect on the biphasic region. The data were fitted with good correlation using the Merchuk equation for the binodal curves and OthmereTobias and Bancroft equations for the tie-lines. The partitioning studies show that there is an uneven distribution of Reactive Yellow HE-4R dye between the phases for all ATPSs and, with a tie-line length increase, there is an increase in the tendency of the dye to partition to the phase in which it interacts most strongly. For ATPSs formed by Li2SO4, the dye is preferentially transferred to the macromolecule-rich phase (top phase), whereas for the system formed by polymer/surfactant, the dye is partitioned to the PVP10k enriched phase (bottom phase).