ISSN:
1572-8927
Keywords:
Ion interaction
;
hannebachite
;
solubility
;
aqueous thermodynamics
;
CaSO3·1/2H2O(c)
;
CaSO 3 0
;
suffite
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract The solubility of CaSO3·1/2H2O(c) was studied under alkaline conditions (pH〉8.2), in deaerated and deoxygenated Na2SO3 solutions ranging in concentration from 0.0002 to 0.4M and in CaCl2 solutions ranging in concentration from 0.0002 to 0.01M, for equilibration periods ranging from 1 to 7 days. Equilibrium was approached from both the over- and the under-saturation directions. In all cases, equilibrium was reached in 〈1 days. The aqueous Ca2+−SO 3 2− ion interactions can be satisfactorily modeled using either ion-association or ion-interaction aqueous thermodynamic models. In the ion-association model, the log K°=2.62±0.07 for Ca2++SO 3 2− ⇆CaSO 3 0 . In the Pitzer ion-interaction model, the binary parameters β(0) and β(1) for Ca2+−SO 4 2− were used, and the value of β(2) was determined from the experimental data. As expected given the strong association constant, the value of β(0) was quite small (about −134). We feel a combination of the two models is most useful. The logarithm of the thermodynamic equilibrium constant (K°) of the CaSO3·1/2H2O(c) solubility reaction (CaSO3·1/2H2O(c)⇆Ca2++SO 3 2+ +0.5H2O) was found to be −6.64±0.07.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00647072
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