Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

In this work, we have developed a novel aqueous two phase system (ATPS) composed of 1, 4-bis-(2-hydroxypropyl)-piperazine (HPP), Na2SO4 and H2O, which can determine the liquid-liquid equilibrium and phase diagrams at the temperatures of 303.15~323.15 K. Simultaneously, the physical properties such as density, viscosity, refractive index, and surface tension have been determined for the top phases and bottom ones of the ATPS. The results indicate that temperature has no significant effect upon the biphasic region, implying a small enthalpy contribution during phase separation. However, the changes in temperature resulte in a decrease of tie line slope, because H2O molecules are transferred from the bottom phase to the top phase. In determining the physical properties of the system, viscosity and refraction index increase with the system components increasing, both during the phase of HPP and Na2SO4. While density and surface tension fall with the increase of system components in the top phase and decrease in the bottom one. ATPS would be a new method for removing the heat-stable salts (HSS) containing sulfuric acid root of absorbent for flue gas desulfurization which is as HPP.