Photolysis of Fe (III)-hydroxy complexes as sources of OH radicals in clouds, fog and rain

doi:10.1016/0960-1686(90)90443-Q

Atmospheric Environment. Part A. General Topics

Volume 24, Issue 1, 1990, Pages 79-89

https://doi.org/10.1016/0960-1686(90)90443-Q Get rights and content

Abstract

Photolysis of the monohydroxy complex of Fe(III), Fe(OH)²⁺, has been proposed as a major source of OH radicals in rain. It is also a significant source of OH radicals in clouds and fog, and probably in some acidic surface waters. Fe(OH)²⁺ is the dominant monomeric Fe(III)-hydroxy complex between pH 2.5 and 5, based on currently available equilibrium constants for Fe(III)-hydroxy complexes. Quantum efficiencies for the photolysis of Fe(OH)²⁺ are 0.04±0.04 at 313 nm and 0.017±0.003 at 360 nm (293 K, ionic strength = 0.03 M). The measured rate constant for midday June sunlight photolysis of Fe(OH)²⁺ is 6.3 × 10⁻⁴s⁻¹ (half life = 18 min). Model calculations based on measured quantum yields and absorption spectra are in satisfactory agreement with measured sunlight photolysis rates of monomeric Fe(III).

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^∗: Current address: School of Forestry and Environmental Studies, Environmental Chemistry Laboratory, Duke University, Durham, NC 27706, U.S.A.

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Photolysis of Fe (III)-hydroxy complexes as sources of OH radicals in clouds, fog and rain

Abstract

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

Atmospheric Environment

J. inorg. nucl. Chem.

J. inorg. nucl. Chem.

Atmospheric Environment

Atmospheric Environment

Envir. Sci. Technol.

Envir. Sci. Technol.

Photochemistry of transition-metal coordination compounds

Chem. Rev.

The Astronomical Almanac for the Year

Photochemistry of Coordination Compounds

Oxidation of aromatic compounds in aqueous solution by free radicals produced by photo-excited electron transfer in iron complexes

J. Am. Chem. Soc.

The photochemical oxidation of benzene in aqueous solution by ferric ion

Trans. Faraday Soc.

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J. Phys. Chem. Ref. Data

Oxidation of ferrous ions by an aliphatic dioxyl radical

J. Chem. Soc., Far. Trans.

The photochemistry of a remote marine stratiform cloud

J. geophys. Res.

The free radical chemistry of cloud droplets and its impact upon the composition of rain

J. geophys. Res.

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The polymerization of acrylonitrile in aqueous solution. Part II. The reaction photosensitized by Fe3+, Fe3+OH−, Fe2+ and I− ions

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The polymerization of acrylamide in aqueous solution

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Nature

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Photoinduced reductive dissolution of α-Fe2O3 by bisulfite

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Photolysis of iron(III)-hydroxy complexes as a source of OH radicals in atmospheric waters—preliminary results

Reactivity of HO₂/O₂⁻ radicals in aqueous solution

Oxidation of SO₂ in rainwater and its role in acid rain chemistry

The polymerization of acrylonitrile in aqueous solution. Part II. The reaction photosensitized by Fe³⁺, Fe³⁺OH⁻, Fe²⁺ and I⁻ ions

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Photoinduced reductive dissolution of α-Fe₂O₃ by bisulfite