The oxidation kinetics of Fe(II) in seawater

Frank J Millero, Sara Sotolongo, Miguel Izaguirre

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Abstract

The oxidation of Fe(II) has been studied as a function of pH (5 to 9), temperature (5 to 45°C), and salinity (0 to 35). The pseudo-first-order rate constant, k1, -d[Fe(II)] dt = k1[Fe(II)] in water and seawater was found to be a second degree function of pH over the pH range of 7.5 to 8.5 at 5°C and 6.0 to 8.0 at 25°C. The overall rate constant (k) -d[Fe(II)] dt = k[Fe(II)][O2][OH-]2 was determined from 5 to 45°C and S = 0 to 35. The results have been fit to an equation of the form (T = 273.15 + t°C) log k = log k0 - 3.29I 1 2 + 1.52I where log k0 = 21.56-1545/T with a standard error = 0.09. The energy of activation for the overall rate constant in water and seawater was 29 ± 2 kJ mol-1. The values of the rate constant for pure water (k0) are in good agreement with literature data. The half times for seawater from some previous studies at a pH = 8.0 were slower than our results for Gulf Stream waters. Measurements on Biscayne Bay waters also yield slower half times apparently due to the presence of organic ligands that can complex Fe(II).

Original languageEnglish (US)
Pages (from-to)793-801
Number of pages9
JournalGeochimica et Cosmochimica Acta
Volume51
Issue number4
DOIs
StatePublished - 1987

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Seawater
Rate constants
seawater
oxidation
kinetics
Oxidation
Kinetics
Water
water
water yield
ligand
salinity
Chemical activation
rate
Ligands
energy
temperature
Temperature

ASJC Scopus subject areas

  • Geochemistry and Petrology

Cite this

The oxidation kinetics of Fe(II) in seawater. / Millero, Frank J; Sotolongo, Sara; Izaguirre, Miguel.

In: Geochimica et Cosmochimica Acta, Vol. 51, No. 4, 1987, p. 793-801.

Research output: Contribution to journalArticle

Millero, FJ, Sotolongo, S & Izaguirre, M 1987, 'The oxidation kinetics of Fe(II) in seawater', Geochimica et Cosmochimica Acta, vol. 51, no. 4, pp. 793-801. https://doi.org/10.1016/0016-7037(87)90093-7
Millero, Frank J ; Sotolongo, Sara ; Izaguirre, Miguel. / The oxidation kinetics of Fe(II) in seawater. In: Geochimica et Cosmochimica Acta. 1987 ; Vol. 51, No. 4. pp. 793-801.
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