Competition between O2 and H2O2 in the oxidation of Fe(II) in natural waters

Melchor González-Dávila; J. Magdalena Santana-Casiano; Frank J. Millero

doi:10.1007/s10953-006-8942-3

Competition between O₂ and H₂O₂ in the oxidation of Fe(II) in natural waters

Melchor González-Dávila, J. Magdalena Santana-Casiano, Frank J. Millero

Ocean Sciences

Research output: Contribution to journal › Article › peer-review

37 Scopus citations

Abstract

The oxidation rates of nanomolar levels of Fe(II) in seawater (salinity S = 36.2) by mixtures of O₂ and H₂O₂ has been measured as a function of pH (5.8-8.4) and temperature (3-35°C). A competition exists for the oxidation of Fe(II) in the presence of both O ₂ (μ mol·L^-1 levels) and H₂O ₂ (nmol·L^-1 levels). A kinetic model has been applied to explain the experimental results that considers the interactions of Fe(II) with the major ions in seawater. In the presence of both oxidants, the hydrolyzed Fe(II) species dominate the Fe(II) oxidation process between pH 6 and 8.5. Over pH range 6.2-7.9, the FeOH⁺ species are the most active, whereas above pH 7.9, the Fe(OH)₂⁰ species are the most active at the levels of CO₃^2- concentration present in seawater. The predicted Fe(II) oxidation rate at [Fe(II)]₀ = 30 nmol·L^-1 and pH = 8.17 in the oxygen-saturated seawater with [H₂O₂]₀ = 50 nmol·L^-1 (log₁₀ k = -2.24 s^-1) is in excellent agreement with the experimental value of log₁₀ k = -2.29 s^-1 ([H ₂O₂]₀ = 55 nmol·L^-1, pH = 8).

Original language	English (US)
Pages (from-to)	95-111
Number of pages	17
Journal	Journal of Solution Chemistry
Volume	35
Issue number	1
DOIs	https://doi.org/10.1007/s10953-006-8942-3
State	Published - Jan 2006

Keywords

Hydrogen peroxide
Iron
Kinetics
Model
Oxidation
Oxygen

ASJC Scopus subject areas

Biophysics
Biochemistry
Molecular Biology
Physical and Theoretical Chemistry

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@article{b445d0aab95f4a4abd14985be566f691,

title = "Competition between O2 and H2O2 in the oxidation of Fe(II) in natural waters",

abstract = "The oxidation rates of nanomolar levels of Fe(II) in seawater (salinity S = 36.2) by mixtures of O2 and H2O2 has been measured as a function of pH (5.8-8.4) and temperature (3-35°C). A competition exists for the oxidation of Fe(II) in the presence of both O 2 (μ mol·L-1 levels) and H2O 2 (nmol·L-1 levels). A kinetic model has been applied to explain the experimental results that considers the interactions of Fe(II) with the major ions in seawater. In the presence of both oxidants, the hydrolyzed Fe(II) species dominate the Fe(II) oxidation process between pH 6 and 8.5. Over pH range 6.2-7.9, the FeOH+ species are the most active, whereas above pH 7.9, the Fe(OH)20 species are the most active at the levels of CO32- concentration present in seawater. The predicted Fe(II) oxidation rate at [Fe(II)]0 = 30 nmol·L-1 and pH = 8.17 in the oxygen-saturated seawater with [H2O2]0 = 50 nmol·L-1 (log10 k = -2.24 s-1) is in excellent agreement with the experimental value of log10 k = -2.29 s-1 ([H 2O2]0 = 55 nmol·L-1, pH = 8).",

keywords = "Hydrogen peroxide, Iron, Kinetics, Model, Oxidation, Oxygen",

author = "Melchor Gonz{\'a}lez-D{\'a}vila and Santana-Casiano, {J. Magdalena} and Millero, {Frank J.}",

note = "Funding Information: We thank C. Moore for her help in making the H2O2 determinations. We also would like to thank Dr. Enrique Gonz{\'a}lez-D{\'a}vila who applied the “Statistica Program” to our data. This study was supported by the Project BQU2003-04010 of Ministerio de Ciencia y Tecnolog{\'i}a from Spain and the Oceanographic Section of National Science Foundation. Copyright: Copyright 2006 Elsevier B.V., All rights reserved.",

year = "2006",

month = jan,

doi = "10.1007/s10953-006-8942-3",

language = "English (US)",

volume = "35",

pages = "95--111",

journal = "Journal of Solution Chemistry",

issn = "0095-9782",

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TY - JOUR

T1 - Competition between O2 and H2O2 in the oxidation of Fe(II) in natural waters

AU - González-Dávila, Melchor

AU - Santana-Casiano, J. Magdalena

AU - Millero, Frank J.

N1 - Funding Information: We thank C. Moore for her help in making the H2O2 determinations. We also would like to thank Dr. Enrique González-Dávila who applied the “Statistica Program” to our data. This study was supported by the Project BQU2003-04010 of Ministerio de Ciencia y Tecnología from Spain and the Oceanographic Section of National Science Foundation. Copyright: Copyright 2006 Elsevier B.V., All rights reserved.

PY - 2006/1

Y1 - 2006/1

N2 - The oxidation rates of nanomolar levels of Fe(II) in seawater (salinity S = 36.2) by mixtures of O2 and H2O2 has been measured as a function of pH (5.8-8.4) and temperature (3-35°C). A competition exists for the oxidation of Fe(II) in the presence of both O 2 (μ mol·L-1 levels) and H2O 2 (nmol·L-1 levels). A kinetic model has been applied to explain the experimental results that considers the interactions of Fe(II) with the major ions in seawater. In the presence of both oxidants, the hydrolyzed Fe(II) species dominate the Fe(II) oxidation process between pH 6 and 8.5. Over pH range 6.2-7.9, the FeOH+ species are the most active, whereas above pH 7.9, the Fe(OH)20 species are the most active at the levels of CO32- concentration present in seawater. The predicted Fe(II) oxidation rate at [Fe(II)]0 = 30 nmol·L-1 and pH = 8.17 in the oxygen-saturated seawater with [H2O2]0 = 50 nmol·L-1 (log10 k = -2.24 s-1) is in excellent agreement with the experimental value of log10 k = -2.29 s-1 ([H 2O2]0 = 55 nmol·L-1, pH = 8).

AB - The oxidation rates of nanomolar levels of Fe(II) in seawater (salinity S = 36.2) by mixtures of O2 and H2O2 has been measured as a function of pH (5.8-8.4) and temperature (3-35°C). A competition exists for the oxidation of Fe(II) in the presence of both O 2 (μ mol·L-1 levels) and H2O 2 (nmol·L-1 levels). A kinetic model has been applied to explain the experimental results that considers the interactions of Fe(II) with the major ions in seawater. In the presence of both oxidants, the hydrolyzed Fe(II) species dominate the Fe(II) oxidation process between pH 6 and 8.5. Over pH range 6.2-7.9, the FeOH+ species are the most active, whereas above pH 7.9, the Fe(OH)20 species are the most active at the levels of CO32- concentration present in seawater. The predicted Fe(II) oxidation rate at [Fe(II)]0 = 30 nmol·L-1 and pH = 8.17 in the oxygen-saturated seawater with [H2O2]0 = 50 nmol·L-1 (log10 k = -2.24 s-1) is in excellent agreement with the experimental value of log10 k = -2.29 s-1 ([H 2O2]0 = 55 nmol·L-1, pH = 8).

KW - Hydrogen peroxide

KW - Iron

KW - Kinetics

KW - Model

KW - Oxidation

KW - Oxygen

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U2 - 10.1007/s10953-006-8942-3

DO - 10.1007/s10953-006-8942-3

M3 - Article

AN - SCOPUS:33644584598

VL - 35

SP - 95

EP - 111

JO - Journal of Solution Chemistry

JF - Journal of Solution Chemistry

SN - 0095-9782

IS - 1

ER -