BIOGENIC MANGANESE OXIDES: Properties and Mechanisms of Formation
Autor: | John R. Bargar, Dorothy L. Parker, Karen J. Murray, Rebecca Verity, Brian G. Clement, Bradley M. Tebo, Samuel M. Webb, Gregory J. Dick |
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Rok vydání: | 2004 |
Předmět: |
X-ray absorption spectroscopy
Primary (chemistry) Birnessite Chemistry Inorganic chemistry Mineralogy chemistry.chemical_element Astronomy and Astrophysics Manganese Multicopper oxidase Redox Metal Octahedron Space and Planetary Science visual_art Earth and Planetary Sciences (miscellaneous) visual_art.visual_art_medium |
Zdroj: | Annual Review of Earth and Planetary Sciences. 32:287-328 |
ISSN: | 1545-4495 0084-6597 |
Popis: | ▪ Abstract Manganese(IV) oxides produced through microbial activity, i.e., biogenic Mn oxides or Mn biooxides, are believed to be the most abundant and highly reactive Mn oxide phases in the environment. They mediate redox reactions with organic and inorganic compounds and sequester a variety of metals. The major pathway for bacterial Mn(II) oxidation is enzymatic, and although bacteria that oxidize Mn(II) are phylogenetically diverse, they require a multicopper oxidase-like enzyme to oxidize Mn(II). The oxidation of Mn(II) to Mn(IV) occurs via a soluble or enzyme-complexed Mn(III) intermediate. The primary Mn(IV) biooxide formed is a phyllomanganate most similar to δ-MnO2or acid birnessite. Metal sequestration by the Mn biooxides occurs predominantly at vacant layer octahedral sites. |
Databáze: | OpenAIRE |
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