University of Oulu

Manninen, M. A. E., Vielma, T. J., & Lassi, U. M. (2023). A Closer Look into Solubility in the Binary NaVO₃–H₂O and NH₄VO₃–H₂O Systems from 298.15 to 333.15 K and 0.1 MPa. Journal of Chemical & Engineering Data, 68(9), 2500–2511.

A closer look into solubility in the binary NaVO₃–H₂O and NH₄VO₃–H₂O systems from 298.15 to 333.15 K and 0.1 MPa

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Author: Manninen, Mikael A. E.1; Vielma, Tuomas J.1; Lassi, Ulla M.1
Organizations: 1Research Unit of Sustainable Chemistry, University of Oulu, 90014 Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2 MB)
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Language: English
Published: American Chemical Society, 2023
Publish Date: 2023-08-28


The solubilities of anhydrous sodium metavanadate (NaVO₃), its hydrated form (NaVO₃·2H₂O), and ammonium metavanadate (NH₄VO₃) in water were measured in the temperature range from 298.15 to 333.15 K using the isothermal saturation method. Previous literature data on the solubility in these binary systems were surveyed, and its reliability was evaluated. Empirical equations were fitted to the accepted data to obtain analytical expressions for the solubilities of the three salts as functions of temperature. Only a few previous papers, mostly published over 60 years ago, were found to report experimental points on the solubility curve of the dihydrate NaVO₃·2H₂O. We herein report new experimental determinations of the dihydrate solubility. Finally, it was investigated whether the solubility of NH₄VO₃ at 298.15 K can be predicted using only thermodynamic data appearing in the literature. Although there seems to be a consensus on the identity of the major species in dilute V(V) solutions, discrepancies in the values of infinite dilution equilibrium constants (I = 0) exist. Accordingly, the solubilities predicted using different sets of equilibrium constants were somewhat scattered but of approximately correct magnitude. The neglect of ion-pair/complex formation and the lack of an accurate model for the activity coefficients are probably the most serious flaws limiting the accuracy of the current models. It is clear that much work remains to be done if temperature-dependent thermodynamic models extending to high vanadium concentrations are to be developed.

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Series: Journal of chemical & engineering data
ISSN: 0021-9568
ISSN-E: 1520-5134
ISSN-L: 0021-9568
Volume: 69
Issue: 9
Pages: 2500 - 2511
DOI: 10.1021/acs.jced.3c00367
Type of Publication: A1 Journal article – refereed
Field of Science: 116 Chemical sciences
Funding: The authors thank Business Finland (Towards Fossil-Free Steel (FFS)-project) and Finnish Cultural Foundation for providing the funding which made this work possible.
Copyright information: © 2022 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.