Journal of Solution Chemistry

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

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

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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© Springer Science+Business Media, LLC 2007

Authors and Affiliations

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

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