Reduction and dissolution of manganese(III) and manganese(IV) oxides by organics. 1. Reaction with hydroquinone
- Creators
- Stone, Alan T.
- Morgan, James J.
Abstract
The chemical processes by which manganese oxides are solubilized by reduction in anoxic waters are poorly understood. A study of the reduction and dissolution of manganese oxide suspensions by hydroquinone was undertaken to determine the rate and mechanism of the solubilization reaction. Dissolution of the manganese-(III,IV) oxide suspension by hydroquinone in the pH range 6.5 < pH < 8.5 is initially described by the following empirical rate law: d[Mn²⁺]/dt = k₁[H⁺]^(0.46)[QH₂]^(1.0)([MnO_x]₀[Mn²⁺]) where [Mn²⁺] is the dissolved manganese concentration, [QH₂] is the hydroquinone concentration, and [MnO_x]₀ is the amount of manganese oxide added. The apparent activation energy was found to be at +37 kJ/mol. Calcium and phosphate inhibited the reaction, by adsorbing on the oxide surface. A model is proposed for the observed rate dependence, according to which complex formation between hydroquinone and manganese oxide surface sites occurs prior to electron transfer.
Additional Information
© 1984 American Chemical Society. Received for review July 1, 1983. Accepted January 6, 1984.Additional details
- Eprint ID
- 106983
- DOI
- 10.1021/es00124a011
- Resolver ID
- CaltechAUTHORS:20201209-122140691
- Created
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2020-12-09Created from EPrint's datestamp field
- Updated
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2021-11-16Created from EPrint's last_modified field