Related Experiment Video
Updated: Jun 24, 2026
06:45
Use of Electron Paramagnetic Resonance in Biological Samples at Ambient Temperature and 77 K
Published on: January 11, 2019
Enhanced reactivity of superoxide in water-solid matrices
Olha Furman1, Derek F Laine, Alexander Blumenfeld
1Department of Civil & Environmental Engineering, Washington State University, Pullman, Washington 99164-2910, USA.
Environmental Science & Technology
|April 9, 2009
Summary
Solid surfaces enhance superoxide reactivity in water, similar to solvents. This finding suggests superoxide generated during in situ chemical oxidation may be more effective at degrading contaminants than previously assumed.
Area of Science:
- Environmental Chemistry
- Oxidation Chemistry
Background:
- Superoxide is generally unreactive in pure water.
- Solvents like hydrogen peroxide (H2O2) can increase superoxide reactivity with organic compounds.
- The role of solid surfaces in enhancing superoxide reactivity remains largely unexplored.
Purpose of the Study:
- To investigate the effect of solid surfaces on superoxide reactivity in aqueous systems.
- To compare surface-catalyzed reactions with homogeneous systems.
- To assess the implications for in situ chemical oxidation (ISCO) applications.
Main Methods:
- Utilized heterogeneous birnessite (gamma-MnO2) to catalyze H2O2 decomposition and generate superoxide.
- Employed electron spin resonance (ESR) spectroscopy to identify reactive species.
- Investigated the degradation of hexachloroethane (HCA) as a superoxide probe.
- Examined the influence of glass bead surface area on HCA degradation rates.
Main Results:
- Birnessite-catalyzed H2O2 decomposition degraded HCA at significantly lower H2O2 concentrations (7.5 mM) compared to homogeneous systems (>100 mM).
- ESR confirmed superoxide as the primary reactive species in the birnessite system.
- HCA degradation rates increased with the surface area of glass beads in heterogeneous systems.
- Solid surfaces were shown to enhance superoxide reactivity, analogous to solvent effects.
Conclusions:
- Solid surfaces, like solvents, enhance the reactivity of superoxide in aqueous environments, potentially by altering its solvation.
- Superoxide generated via catalyzed H2O2 propagations (CHP) in ISCO may exhibit greater efficacy against highly oxidized contaminants than previously recognized.
Related Concept Videos
01:21Radical Oxidation of Allylic and Benzylic Alcohols
Activated manganese(IV) oxide can selectively oxidize allylic and benzylic alcohols via a radical intermediate mechanism. Primary allylic alcohols are oxidized to aldehydes, while secondary allylic alcohols yield ketones. The redox reaction of potassium permanganate with an Mn(II) salt such as manganese sulfate (under either alkaline or acidic conditions), followed by thorough drying, yields the oxidizing agent: activated MnO2. While MnO2 is insoluble in the solvents used for the reaction, the...
01:11Radical Reactivity: Overview
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired molecule. These three...
01:17Oxidation of Phenols to Quinones
In the presence of oxidizing agents, phenols are oxidized to quinones. Quinones can be easily reduced back to phenols using mild reducing agents. The electron-donating hydroxyl group enhances the reactivity of the aromatic ring, enabling oxidation of the ring even in the absence of an α hydrogen.
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
o-hydroxy phenols are oxidized to o-quinones and p-hydroxy phenols to p-quinones. Such redox reactions involve the transfer of two electrons and two protons. The reversible redox property is crucial in...
02:37Oxidation of Alcohols
In this lesson, the oxidation of alcohols is discussed in depth. The various reagents used for oxidation of primary and secondary alcohols are detailed, and their mechanism of action is provided.
The process of oxidation in a chemical reaction is observed in any of the three forms:
The process of oxidation in a chemical reaction is observed in any of the three forms:
01:20Radical Autoxidation
The oxidation of an organic compound in the presence of air or oxygen is called autoxidation. For example, cumene reacts with oxygen to form hydroperoxide. Autoxidation involves initiation, propagation, and termination steps. Many organic compounds are susceptible to autoxidation—especially ethers in the presence of oxygen, which form hydroperoxides. Even though this reaction is slow, old ether bottles contain small amounts of peroxide, which leads to laboratory explosions during ether...
00:54Radical Formation: Homolysis
A bond is formed between two atoms by sharing two electrons. When this bond is broken by supplying sufficient energy, either two electrons can be taken up by one atom forming ions by the cleavage called heterolysis, or the two electrons are shared by two atoms, with one each creating radicals by the cleavage called homolysis.