Determination of Volume Properties of Aqueous Vanadyl Sulfate at 283.15 to 323.15 K
journal contributionposted on 30.04.2014, 00:00 by Wei-Guo Xu, Ye Qin, Fei Gao, Jian-Guo Liu, Chuan-Wei Yan, Jia-Zhen Yang
This paper reports the densities of aqueous VOSO4 that were measured by an Anton Paar DMA 4500 M from 0.0500 mol·kg–1 to 3.000 mol·kg–1 at 283.15 to 323.15 K. The apparent molar volume, ϕVB, the partial molar volume of VOSO4, V̅B, the apparent molar expansibility of the solute, ϕE, and coefficient of thermal expansion of the solution, α, were calculated. First, these properties described above have been discussed with the temperature and concentration variation. Then the values of the apparent molar volume, ϕVB, were fitted to Pitzer’s model for volumetric properties by the method of the least squares, which allowed the partial molar volume of the VOSO4 at infinite dilution, V̅B0, and Pitzer’s parameters, βMX(0)V, βMX(1)V, and CMXV, to be obtained. The small standard deviations of the fitting show that Pitzer’s model is also appropriate for representing the volumetric properties of aqueous solutions of VOSO4. Using the data from literature, the partial molar volume of the ion VO2+ at infinite dilution, V̅C0, was discussed and the result showed that the negative value of V̅C0 can be attributed to strong hydration of VO2+ as other divalent ions.