GEOC 80 |
| Minori Uchimiya, Department of Geography and Environmental Engineering, Johns Hopkins University, Whiting School of Engineering, 3400 North Charles Street, Baltimore, MD 21218 and Alan T. Stone, Department of Geography & Environmental Engineering, The Johns Hopkins University, 313 Ames Hall, 3400 North Charles Street, Baltimore, MD 21218. |
| Two widely accepted hypotheses are that quinones are important redox-active moieties within natural organic matter and that quinones serve as electron shuttles between iron-respiring bacteria and mineral surfaces. In this work, quinone-quinone cross-reactions, Fe(II) oxidation by benzoquinones, and Fe(III) reduction by hydroquinones and catechols are being investigated as a way to help test theses hypotheses. Cross reactions involving low molecular weight quinones occur quickly. Reactions involving iron are acutely sensitive to iron speciation and to quinone structure and chemical properties. All reactions under consideration are reversible and near equilibrium. Indeed, thermodynamics places important constrains on the progress of reactions involving quinones. |
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Microbially Mediated Manganese and Iron Oxidation in the Biosphere
1:30 PM-5:05 PM, Tuesday, March 30, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |