Thermodynamic Properties of the β-Diketone-ZnSO4-(NH4)2SO4-NH3(aq)-H2O System

Solubility of beta-diketone (4-ethyl-1-phenyl-1, 3-octadione, abbreviated as HA, C16H22O2, molecular weight, 246.34)-ZnSO4-(NH4)(2)SO4-NH3(aq)-H2O system at T = (298.15, 308.15) K is elaborately measured by isothermal method. The results show that the solubility of ZnA(2(o)), NH(4)A((o)), H2O(o), Zn-(w)(2+), NH4(w)+, WO4(w)2-, and HA((w)) increases with the increase of the concentration of zinc sulfate. In contrast, the solubility of HA((o)), H2O(w), and NH3(w) decreases with the increase of the concentration of zinc sulfate. The distribution ratio and extraction equilibrium isotherm of zinc in extraction system are obtained at T = (298.15, 308.15) K. The consequence indicates that extraction equilibrium isotherm is connected with temperature, and at the same condition, the distribution ratio of Zn(II) at 298.15 K is greater than 308.15 K. The activity coefficient of the components in mixture electrolyte solutions is calculated by Pitzer model, and the activity coefficient in organic phase is gained by correlating the extraction thermodynamic equilibrium constant with Gibbs-Duhem formula.