Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • 1995-1999  (2)
  • equilibrium constant  (2)
  • Solanum brevidens
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 24 (1995), S. 837-877 
    ISSN: 1572-8927
    Keywords: Magnetite ; iron oxide ; ferrous and ferric ion hydrolysis ; phosphatocomplexing ; equilibrium constant ; pressurized water ; hydrothermal solutions ; corrosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A platinum-lined flowing autocláve facility was used to investigate the solubility behavior of magnetite (Fe3O4) in alkaline sodium phosphate and ammonium hydroxide solutions between 21 and 288°C. Measured iron solubilities were interpreted via a Fe(II)/Fe(III) ion hydroxo-, phosphato-, and ammino-complexing model and thermodynamic functions for these equilibria were obtained from a least-squares analysis of the data. A total of 14 iron ion species were fitted. Complexing equilibria are reported for 8 new species: Fe(OH)(HPO4)−, Fe(OH)2(HPO4)2−, Fe(OH)3(HPO4)2−, Fe(OH)(NH3)+, Fe(OH)2(PO4)3−, Fe(OH)4(HPO4)3−, Fe(OH)2(H2PO4)−, and Fe(OH)3(H2PO4)3−. At elevated temperatures, hydrolysis and phosphato complexing tended to stabilize Fe(III) relative to Fe(II), as evidenced by free energy changes fitted to the oxidation reactions. $$\begin{gathered} Fe(OH)_3^ - + H_2 O_ \leftarrow ^ \to Fe(OH)_4^ - + (1/2)H_2 (g) \hfill \\ Fe(OH)_2^{} (HPO_4 )^{2 - } + H_2 O_ \leftarrow ^ \to Fe(OH)_3 (HPO_4 )^{2 - } + (1/2)H_2 (g) \hfill \\ \end{gathered}$$ For temperatures below 83°C and for a dissolved hydrogen concentration of 234 μmol-kg−1, the activity of ferrous iron in aqueous solution is controlled by a hydrous Fe(II) oxide solid phase rather than magnetite.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of solution chemistry 27 (1998), S. 33-66 
    ISSN: 1572-8927
    Keywords: Chromium(III) oxide ; eskolaite ; chromium(III) oxide hydroxide ; chromium(III) hydroxide dehydration ; ferrous chromite ; aqueous solutions ; chromium(III) ion hydrolysis ; phosphatocomplexing ; equilibrium constant ; pressurized water ; hydrothermal solutions ; corrosion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A platinum-lined, flowing autoclave facility is used to investigate the solubility behavior of Cr2O3 and FeCr2O4 in alkaline sodium phosphate, sodium hydroxide, and ammonium hydroxide solutions between 21 and 288°C. Baseline Cr(III) ion solubilities were found to be on the order of 0.1 nmolal, which were enhanced by the formation of anionic hydroxo and phosphato complexes. At temperatures below 51°C, the activity of Cr(III) ions in aqueous solution is controlled by a Cr(OH)3·3H2O solid phase rather than Cr2O3; above 51°C the saturating solid phase is γ-CrOOH. Measured chromium solubilities were interpreted via a Cr(III) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reaction equilibria were obtained from least-squares analyses of the data. The existence of four new Cr(III) ion complexes is reported: Cr(OH)3(H2PO4)−, Cr(OH)3(HPO4)2−, Cr(OH)3(PO4)3−, and Cr(OH)4(HPO4)-(H2PO4)4−. The last species is the dominant Cr(III) ion complex in concentrated, alkaline phosphate solutions at elevated temperatures.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...