Reduction and dissolution of manganese(III) and manganese(IV) oxides by organics. 1. Reaction with hydroquinone

Journal Article · Fri Jun 01 04:00:00 EDT 1984 · Environ. Sci. Technol.; (United States)

DOI:https://doi.org/10.1021/es00124a011· OSTI ID:6414512

Stone, A T; Morgan, J J

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(Mn/sup 2 +/)/dt = k/sub 1/(H/sup +/)sup 0.46(QH/sub 2/)/sup 1.0/((MnO/sub x/)/sub 0/ - (Mn/sup 2 +/)) where (Mn/sup 2 +/) is the dissolved manganese concentration, (QH/sub 2/) is the hydroquinone concentration, and (MnO/sub x/)/sub 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.

• Research Organization: California Inst. of Tech., Pasadena
• OSTI ID: 6414512
• Journal Information: Environ. Sci. Technol.; (United States), Journal Name: Environ. Sci. Technol.; (United States) Vol. 18:6; ISSN ESTHA
• Country of Publication: United States
• Language: English

Related Subjects

520200* -- Environment
Aquatic-- Chemicals Monitoring &amp; Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACTIVATION ENERGY
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMICAL STATE
CHEMISTRY
DISSOLUTION
ENERGY
EQUATIONS
KINETICS
MANGANESE COMPOUNDS
MANGANESE OXIDES
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
QUINONES
REDUCTION
TRANSITION ELEMENT COMPOUNDS
WATER CHEMISTRY