Reductive dissolution of manganese(III/IV) oxides by substituted phenols

Journal Article · Thu Oct 01 00:00:00 EDT 1987 · Environ. Sci. Technol.; (United States)

DOI:https://doi.org/10.1021/es50001a011· OSTI ID:5350671

Stone, A T

Kinetics of the reaction of manganese(III/IV) oxides with 11 substituted phenols were examined in order to assess the importance of manganese oxides in the abiotic degradation of phenolic pollutants. At pH 4.4, 10/sup -4/ M solutions of substituted phenols reduced and dissolved synthetic manganese oxide particles in the following order: p-methylphenol > p-ethylphenol > m-methylphenol > p-chlorophenol > phenol > m-chlorophenol > p-hydroxybenzoate > o-hydroxybenzoate > 4'-hydroxyacetophenone > p-nitrophenol. Rates of reductive dissolution generally decrease as the Hammett constants of ring substituents become more positive, reflecting trends in the basicity, nucleophilicity, and half-wave potential of substituted phenols. Evidence indicates that the fraction of oxide surface sites occupied by substituted phenols is quite low. The apparent reaction order with respect to (H/sup +/) is not a constant but varies between 0.45 and 1.30 as the pH range, phenol concentration, and phenol structure are varied. A mechanism for the surface chemical reaction has been postulated to account for these effects.

• Research Organization: Johns Hopkins Univ., Baltimore, MD (USA)
• OSTI ID: 5350671
• Journal Information: Environ. Sci. Technol.; (United States), Vol. 21:10
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
MANGANESE OXIDES
ENVIRONMENTAL EFFECTS
REDUCTION
PHENOLS
DECOMPOSITION
CHEMICAL REACTION KINETICS
EXPERIMENTAL DATA
SURFACE WATERS
WATER CHEMISTRY
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DATA
HYDROXY COMPOUNDS
INFORMATION
KINETICS
MANGANESE COMPOUNDS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
TRANSITION ELEMENT COMPOUNDS
520200* - Environment
Aquatic- Chemicals Monitoring & Transport- (-1989)