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Oxidation of a Dimethoxyhydroquinone by Ferrihydrite and Goethite Nanoparticles : Iron Reduction versus Surface Catalysis

Krumina, Lelde LU ; Lyngsie, Gry LU ; Tunlid, Anders LU and Persson, Per LU (2017) In Environmental Science and Technology 51(16). p.9053-9061
Abstract

Hydroquinones are important mediators of electron transfer reactions in soils with a capability to reduce Fe(III) minerals and molecular oxygen, and thereby generating Fenton chemistry reagents. This study focused on 2,6-dimethoxy hydroquinone (2,6-DMHQ), an analogue to a common fungal metabolite, and its reaction with ferrihydrite and goethite under variable pH and oxygen concentrations. Combined wet-chemical and spectroscopic analyses showed that both minerals effectively oxidized 2,6-DMHQ in the presence of oxygen. Under anaerobic conditions the first-order oxidation rate constants decreased by one to several orders of magnitude depending on pH and mineral. Comparison between aerobic and anaerobic results showed that ferrihydrite... (More)

Hydroquinones are important mediators of electron transfer reactions in soils with a capability to reduce Fe(III) minerals and molecular oxygen, and thereby generating Fenton chemistry reagents. This study focused on 2,6-dimethoxy hydroquinone (2,6-DMHQ), an analogue to a common fungal metabolite, and its reaction with ferrihydrite and goethite under variable pH and oxygen concentrations. Combined wet-chemical and spectroscopic analyses showed that both minerals effectively oxidized 2,6-DMHQ in the presence of oxygen. Under anaerobic conditions the first-order oxidation rate constants decreased by one to several orders of magnitude depending on pH and mineral. Comparison between aerobic and anaerobic results showed that ferrihydrite promoted 2,6-DMHQ oxidation both via reductive dissolution and heterogeneous catalysis while goethite mainly caused catalytic oxidation. These results were in agreement with changes in the reduction potential (EH) of the Fe(III) oxide/Fe(II)aq redox couple as a function of dissolved Fe(II) where EH of goethite was lower than ferrihydrite at any given Fe(II) concentration, which makes ferrihydrite more prone to reductive dissolution by the 2,6-DMBQ/2,6-DMHQ redox couple. This study showed that reactions between hydroquinones and iron oxides could produce favorable conditions for formation of reactive oxygen species, which are required for nonenzymatic Fenton-based decomposition of soil organic matter.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Environmental Science and Technology
volume
51
issue
16
pages
9 pages
publisher
The American Chemical Society
external identifiers
  • scopus:85027437003
  • wos:000407987400019
ISSN
0013-936X
DOI
10.1021/acs.est.7b02292
language
English
LU publication?
yes
id
5926beca-9de4-4b7e-a8fe-fe442ba2f9c8
date added to LUP
2017-09-07 10:14:28
date last changed
2018-01-16 13:25:18
@article{5926beca-9de4-4b7e-a8fe-fe442ba2f9c8,
  abstract     = {<p>Hydroquinones are important mediators of electron transfer reactions in soils with a capability to reduce Fe(III) minerals and molecular oxygen, and thereby generating Fenton chemistry reagents. This study focused on 2,6-dimethoxy hydroquinone (2,6-DMHQ), an analogue to a common fungal metabolite, and its reaction with ferrihydrite and goethite under variable pH and oxygen concentrations. Combined wet-chemical and spectroscopic analyses showed that both minerals effectively oxidized 2,6-DMHQ in the presence of oxygen. Under anaerobic conditions the first-order oxidation rate constants decreased by one to several orders of magnitude depending on pH and mineral. Comparison between aerobic and anaerobic results showed that ferrihydrite promoted 2,6-DMHQ oxidation both via reductive dissolution and heterogeneous catalysis while goethite mainly caused catalytic oxidation. These results were in agreement with changes in the reduction potential (E<sub>H</sub>) of the Fe(III) oxide/Fe(II)<sub>aq</sub> redox couple as a function of dissolved Fe(II) where E<sub>H</sub> of goethite was lower than ferrihydrite at any given Fe(II) concentration, which makes ferrihydrite more prone to reductive dissolution by the 2,6-DMBQ/2,6-DMHQ redox couple. This study showed that reactions between hydroquinones and iron oxides could produce favorable conditions for formation of reactive oxygen species, which are required for nonenzymatic Fenton-based decomposition of soil organic matter.</p>},
  author       = {Krumina, Lelde and Lyngsie, Gry and Tunlid, Anders and Persson, Per},
  issn         = {0013-936X},
  language     = {eng},
  month        = {08},
  number       = {16},
  pages        = {9053--9061},
  publisher    = {The American Chemical Society},
  series       = {Environmental Science and Technology},
  title        = {Oxidation of a Dimethoxyhydroquinone by Ferrihydrite and Goethite Nanoparticles : Iron Reduction versus Surface Catalysis},
  url          = {http://dx.doi.org/10.1021/acs.est.7b02292},
  volume       = {51},
  year         = {2017},
}