The oxidation of Fe(II) with H sub 2 O sub 2 in seawater

Journal Article · Tue Aug 01 00:00:00 EDT 1989 · Geochimica et Cosmochimica Acta; (USA)

DOI:https://doi.org/10.1016/0016-7037(89)90307-4· OSTI ID:7164455

Millero, F J; Sotolongo, S ^[1]

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1. Univ. of Miami, FL (USA)

The oxidation of Fe(II) with H{sub 2}O{sub 2} has been measured in seawater as a function of pH (2 to 8.5), temperature (5 to 45{degree}C) and salinity (0 to 35). The effect of pH on the rate constant, k, was found to be a linear function of (H{sup +}) or (OH{sup {minus}}) from pH = 6 to 8. The effect of temperature and ionic strength on k at pH = 6.0 was also compared. If the rates are expressed as d(Fe(II))dt = {minus}k{sub 2}(Fe(II))(H{sub 2}O{sub 2})(OH{sup {minus}}) the values of k{sub 2} are independent of temperature. This is due to the fact that the energy of activation of k is the same order of magnitude of {Delta}H{sup *}{sub w}, the heat of ionization of water. The ionic strength dependence of k{sub 2} was then compared. The results of k over the entire pH, temperature and ionic strength are given. The addition of HCO{sup {minus}}{sub 3} at a constant pH was found to linearily increase the rate independent of the salinity and temperature. This may be related to FeCO{sup 0}{sub 3} reacting faster than FeOH{sup +} with H{sub 2}O{sub 2}. At a given pH and ionic strength, the rates in seawater are nearly the same as in NaCl.

• OSTI ID: 7164455
• Journal Information: Geochimica et Cosmochimica Acta; (USA), Vol. 53:8; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
IRON COMPOUNDS
CHEMICAL REACTION KINETICS
OXIDATION
SEAWATER
GEOCHEMISTRY
HYDROGEN PEROXIDE
IONIC COMPOSITION
IONIC POTENTIAL
IRON IONS
PH VALUE
SALINITY
TEMPERATURE EFFECTS
WATER CHEMISTRY
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
HYDROGEN COMPOUNDS
IONS
KINETICS
OXYGEN COMPOUNDS
PEROXIDES
REACTION KINETICS
TRANSITION ELEMENT COMPOUNDS
WATER
580000* - Geosciences