Photoassisted dissolution of a colloidal manganese oxide in the presence of fulvic acid

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · Environ. Sci. Technol.; (United States)

OSTI ID:6606818

Walte, T D; Wrigley, I C; Szymczak, R

The dissolution of a synthesized manganese dioxide by a well-characterized fulvic acid has been investigated over a range of reactant concentrations, pH, and illumination conditions, as have components of the overall dissolution process including fulvic acid and manganous ion adsorption to the oxide surface. The dissolution process is satisfactorily described by an initial rapid formation of a surface-located precursor complex followed by a slower intramolecular electron-transfer step resulting in Mn(II) formation at the oxide surface. Illumination by 365-nm light enhances the rate of electron transfer significantly, with an increase in first-order reduction rate constant from 0.31 min/sup -1/ (dark) to 0.55 min/sup -1/ (light at pH 4.00 and from 0.53 min/sup -1/ (dark) to 1.23 min/sup -1/ (light) at pH 7.10. Depending on the affinity of the oxide surface for manganous ion, a portion of the Mn(II) produced at the oxide surface will be rapidly released to solution, resulting in dissolution of the oxide.

• Research Organization: Australian Nuclear Science and Technology Organization, Menai
• OSTI ID: 6606818
• Journal Information: Environ. Sci. Technol.; (United States), Journal Name: Environ. Sci. Technol.; (United States) Vol. 22:7; ISSN ESTHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
520200* -- Environment
Aquatic-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DISSOLUTION
ELECTRON TRANSFER
FULVIC ACIDS
MANGANESE COMPOUNDS
MANGANESE OXIDES
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
PHOTOCHEMISTRY
TRANSITION ELEMENT COMPOUNDS