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Per Persson. Photo.

Per Persson

Director

Per Persson. Photo.

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

Author

  • Lelde Krumina
  • Gry Lyngsie
  • Anders Tunlid
  • Per Persson

Summary, in English

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.

Department/s

  • Centre for Environmental and Climate Science (CEC)
  • MEMEG
  • BECC - Biodiversity and Ecosystem services in a Changing Climate
  • Microbial Ecology

Publishing year

2017-08-15

Language

English

Pages

9053-9061

Publication/Series

Environmental Science and Technology

Volume

51

Issue

16

Document type

Journal article

Publisher

The American Chemical Society (ACS)

Topic

  • Geochemistry

Status

Published

Project

  • MICCS - Molecular Interactions Controlling soil Carbon Sequestration

Research group

  • Microbial Ecology

ISBN/ISSN/Other

  • ISSN: 0013-936X