Journal of Solution Chemistry

, Volume 36, Issue 11–12, pp 1479–1493 | Cite as

The Oxidation of Iron(II) with Oxygen in NaCl Brines

  • J. Michael Trapp
  • Frank J. Millero
Special Issue Dedicated to Joseph Antoine Rard


The oxidation of nanomolar levels of iron(II) with oxygen has been studied in NaCl solutions as a function of temperature (0 to 50 °C), ionic strength (0.7 to 5.6 mol⋅kg−1), pH (6 to 8) and concentration of added NaHCO3 (0 to 10 mmol⋅kg−1). The results have been fitted to the overall rate equation:
The values of k app have been examined in terms of the Fe(II) complexes with OH and CO 3 2− . The overall rate constants are given by:
where α i is the molar fraction and k i is the rate constant of species i. The individual rate constants for the species of Fe(II) interacting with OH and CO 3 2− have been fitted by equations of the form:
$$\begin{array}{l}\ln k_{\mathrm{Fe}2+}=21.0+0.4I^{0.5}-5562/T\\[6pt]\ln k_{\mathrm{FeOH}}=17.1+1.5I^{0.5}-2608/T\\[6pt]\ln k_{\mathrm{Fe(OH)}2}=-6.3-0.6I^{0.5}+6211/T\\[6pt]\ln k_{\mathrm{Fe(CO3)}2}=31.4+5.6I^{0.5}-6698/T\end{array}$$
These individual rate constants can be used to estimate the rates of oxidation of Fe(II) over a large range of temperatures (0 to 50 °C) in NaCl brines (I=0 to 6 mol⋅kg−1) with different levels of OH and CO 3 2− .


Fe(II) Oxidation NaCl Brines 


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  1. 1.
    Stumm, W., Lee, G.F.: Oxygenation of ferrous iron. Ind. Eng. Chem. 53, 143–146 (1961) CrossRefGoogle Scholar
  2. 2.
    Lowson, R.T.: Aqueous oxidation of pyrite by molecular oxygen. Chem. Rev. 82, 461–499 (1982) CrossRefGoogle Scholar
  3. 3.
    Sung, W., Morgan, J.J.: Kinetics and product of ferrous oxygenation in aqueous solutions. Environ. Sci. Technol. 14, 561–568 (1980) CrossRefGoogle Scholar
  4. 4.
    Millero, F.J.: The effect of ionic interactions on the oxidation of metals in natural waters. Geochim. Cosmochim. Acta 49, 547–553 (1985) CrossRefGoogle Scholar
  5. 5.
    Roekens, E.J., Van Grieken, R.E.: Kinetics of iron (II) oxidation in seawater of various pH. Mar. Chem. 13, 195–202 (1983) CrossRefGoogle Scholar
  6. 6.
    Wilkins, R.G.: The Study of Kinetics and Mechanism of Reactions of Transition Metal Complexes, p. 403. Allyn and Bacon, Boston (1974) Google Scholar
  7. 7.
    Baes, C.F., Mesmer, R.E.: Iron. In: Baes, C.F., Mesmer, R.E. (eds.) The Hydrolysis of Cations, p. 489. Wiley, New York (1976) Google Scholar
  8. 8.
    Millero, F.J., Izaguirre, M.: Effect of ionic strength and ionic interactions on the oxidation of Fe(II). J. Solution Chem. 18, 585–599 (1989) CrossRefGoogle Scholar
  9. 9.
    Millero, F.J., Izaguirre, M., Sharma, V.K.: The effect of ionic interactions on the rates of oxidation in natural waters. Mar. Chem. 22, 179–191 (1990) CrossRefGoogle Scholar
  10. 10.
    Millero, F.J., Sotolongo, S.: The oxidation of Fe(II) with H2O2 in seawater. Geochim. Cosmochim. Acta 53, 1867–1873 (1989) CrossRefGoogle Scholar
  11. 11.
    Millero, F.J., Sotolongo, S., Izaguirre, M.: The kinetics of oxidation of Fe(II) in seawater. Geochim. Cosmochim. Acta 51, 793–801 (1987) CrossRefGoogle Scholar
  12. 12.
    Millero, F.J., Stade, D.J., Sotolongo, S., Vega, C.: The effect of ionic interactions on the oxidation of Fe(II) with H2O2. J. Solution Chem. 20, 1079–1092 (1991) CrossRefGoogle Scholar
  13. 13.
    Ghosh, M.M.: Oxygenation of ferrous iron(II) in highly buffered water. In: Rubin, A.J. (ed.) Aqueous Environment of Metals, pp. 193–217. Ann Arbor Science, Ann Arbor (1974) Google Scholar
  14. 14.
    King, D.W.: Role of carbonate speciation on the oxidation rate of Fe(II) in aquatic systems. Environ. Sci. Technol. 32, 2997–3003 (1998) CrossRefGoogle Scholar
  15. 15.
    King, D.W., Lounsbury, H.A., Millero, F.J.: Rates and mechanism of Fe(II) oxidation at nanomolar total iron concentrations. Environ. Sci. Technol. 29, 818–824 (1995) CrossRefGoogle Scholar
  16. 16.
    Santana-Casiano, J.M., Gonzalez-Davila, M., Rodriquez, M.J., Millero, F.J.: The effects of organic compounds in the oxidation kinetics of Fe(II). Mar. Chem. 70, 211–222 (2000) CrossRefGoogle Scholar
  17. 17.
    Santana-Casiano, J.M., Gonzalez-Davila, M., Millero, F.J.: The oxidation of Fe(II) in NaCl-HCO3 and seawater solutions in the presence of phthalate and salicylate ions: a kinetic model. Mar. Chem. 85, 27–40 (2004) CrossRefGoogle Scholar
  18. 18.
    Santana-Casiano, J.M., Gonzalez-Davila, M., Rodriquez, M.J., Millero, F.J.: Oxidation of nanomolar levels of iron(II) with oxygen in seawater. Environ. Sci. Technol. 39, 2073–2079 (2005) CrossRefGoogle Scholar
  19. 19.
    González-Davila, M., Santana-Casiano, J.M., Millero, F.J.: Competition between O2 and H2O2 in the oxidation of Fe(II) in natural waters. J. Solution Chem. 35, 95–111 (2006) CrossRefGoogle Scholar
  20. 20.
    Harber, F., Weiss, J.: The catalytic decomposition of hydrogen peroxide by iron salts. Proc. R. Soc. London (Ser. A) 149, 332–351 (1934) CrossRefGoogle Scholar
  21. 21.
    Zhang, J.Z., Kelble, C., Millero, F.J.: Gas-segmented continuous flow analysis of iron in water with a long liquid waveguide capillary flow cell. Anal. Chim. Acta 438, 49–57 (2001) CrossRefGoogle Scholar
  22. 22.
    Lo Surdo, A., Alzola, E.M., Millero, F.J.: The PVT properties of concentrated aqueous electrolytes. I. Densities and apparent molal volume of NaCl, Na2SO4, MgCl2, and MgSO4 solutions from 0.1 mol⋅kg−1 to saturation and from 273.15 to 323.15 K. J. Chem. Thermodyn. 13, 649–662 (1982) CrossRefGoogle Scholar
  23. 23.
    Millero, F.J., Yao, W., Aicher, J.: The speciation of Fe(II) and Fe(III) in seawater. Mar. Chem. 50, 21–39 (1995) CrossRefGoogle Scholar
  24. 24.
    Millero, F.J., Pierrot, D.: A chemical equilibrium model for natural waters. Aqua Geochem. 4, 153–199 (1998) CrossRefGoogle Scholar
  25. 25.
    Millero, F.J., Huang, F., Laferriere, A.L.: Solubility of oxygen in the major sea salts as a function of temperature and concentration. Mar. Chem. 78, 217–230 (2002) CrossRefGoogle Scholar
  26. 26.
    González-Davila, M., Santana-Casiano, J.M., Millero, F.J.: Oxidation of iron(II) nanomolar with H2O2 in seawater. Geochim. Cosmochim. Acta 68(Suppl.), A377 (2004), abstracts of the 13th Annual V.M. Goldschmidt Conference, Copenhagen, Denmark, June 5–11, 2004 Google Scholar

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© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  1. 1.Rosenstiel School of Marine and Atmospheric ScienceUniversity of MiamiMiamiUSA

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