Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T=298.15 and 323.15 K, and Representation with an Extended Ion-Interaction (Pitzer) Model

Abstract

Isopiestic vapor-pressure measurements were made for Li 2 SO 4 (aq) from 0.1069 to 2.8190 mol·kg -1 at 298.15 K, and from 0.1148 to 2.7969 mol·kg -1 at 323.15 K, with NaCl(aq) as the reference standard. Published thermodynamic data for this system were

Water Activity Data Assessment to Be Used in Hanford Waste Solubility Calculations

“…At 298.15 K, Leopold et al (1927) predicts a saturation vapor pressure of 0.860, which is very close to the 0.866 reported by Rard (1981) and the value of 0.865 reported by Rard et al (2000). However, the ionic strengths at saturation are very different between the Rard et al (1981;2000) and the Leopold et al (1927) data (9.5 molal versus 11.1 molal in Rard, 1981). Thus, there appears to be an error in the concentration at saturation reported by Leopold et al (1927) and, therefore, these data were excluded from the study.…”

“…The Leopold et al (1927) data changes both ionic strength and temperature because they measured the water activity in solutions that are at saturation with respect to sodium sulfate. At 298.15 K, Leopold et al (1927) predicts a saturation vapor pressure of 0.860, which is very close to the 0.866 reported by Rard (1981) and the value of 0.865 reported by Rard et al (2000). However, the ionic strengths at saturation are very different between the Rard et al (1981;2000) and the Leopold et al (1927) data (9.5 molal versus 11.1 molal in Rard, 1981).…”

“…There are four datasets Rard and Miller, 1981;Rard et al, 2000;Robinson et al, 1941) available in the Na2S04 system with data at 298.15 K. Figure 5 plots these data and shows that all four are consistent with each other. There is additional data, reported by Gibson et al (1933), with data at 300 K. These data at 300 K are not appreciably different than the data at 298.15 K shown in Figure 3, as expected for such a small temperature change.…”

Isopiestic Determination of the Osmotic and Activity Coefficients of Li2SO4(aq) at T=298.15 and 323.15 K, and Representation with an Extended Ion-Interaction (Pitzer) Model

“…Consequently, their thermodynamic properties have been widely studied and models are available that represent these thermodynamic properties over wide ranges of molality and temperature [1][2][3]. Thermodynamic data for the more rare alkali metal sulfates Rb 2 SO 4 (aq) and Cs 2 SO 4 (aq) are much less extensive.…”

Isopiestic Investigation of the Osmotic and Activity Coefficients of {yMgCl2+(1−y)MgSO4}(aq) and the Osmotic Coefficients of Na2SO4⋅MgSO4(aq) at 298.15 K

“…However, their osmotic coefficients for Na 2 SO 4 (aq) are discrepant from most other studies as noted in references [30,47] and thus it is likely that their osmotic coefficients for Na 2 SO 4 + MgSO 4 + H 2 O mixtures are skewed as a function of y. As noted in the introduction, the results cited in reference [29] were not available to us.…”