Reactions of nitrite with goethite and surface Fe(II)-goethite complexes

P. Dhakal, M. S. Coyne, D. H. McNear, O. O. Wendroth, M. M. Vandiviere, E. M. D'Angelo, C. J. Matocha

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11 Scopus citations


Chemodenitrification-the abiotic (chemical) reduction of nitrite (NO2) by iron (II)-plays an important role in nitrogen cycling due in part to this process serving as a source of nitrous oxide (N2O). Questions remain about the fate of NO2 in the presence of mineral surfaces formed during chemodenitrification, such as iron(III) (hydr) oxides, particularly relative to dissolved iron(II). In this study, stirred-batch kinetic experiments were conducted under anoxic conditions (to mimic iron(III)-reducing conditions) from pH 5.5–8 to investigate NO2 reactivity with goethite (FeOOH(s)) and Fe(II)-treated goethite using wet chemical and attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy. Nitrite removal from solution by goethite was more rapid at pH 5.5 than at pH 7 and 8. Spectral changes upon nitrite adsorption imply an inner-sphere surface interaction (monodentate and bidentate) at pH 5.5 based on ATR-FTIR spectra of the nitrite-goethite interface over time. In iron(II)-amended experiments at pH 5.5 with high aqueous Fe(II) in equilibrium with goethite, nitrous oxide was generated, indicating that nitrite removal involved a combination of sorption and reduction processes. The presence of a surface complex resembling protonated nitrite (HONO) with an IR peak near ~1258 cm−1 was observed in goethite-only and iron(II)-goethite experiments, with a greater abundance of this species observed in the latter treatment. These results might help explain gaseous losses of nitrogen where nitrite and iron(II)/goethite coexist, with implications for nutrient cycling and release of atmospheric air pollutants.

Original languageEnglish
Article number146406
JournalScience of the Total Environment
StatePublished - Aug 15 2021

Bibliographical note

Funding Information:
The authors thank Dr. Mike Sharkey for help with scanning electron microscopy. We greatly acknowledge funding for this work by the National Research Initiative Competitive Grant no. 2007-35107-18311 from the USDA Cooperative State Research, Education, and Extension service and the Department of Plant and Soil Sciences, University of Kentucky . The comments of two anonymous reviewers and Dr. Andreas Kappler are greatly appreciated.

Publisher Copyright:
© 2021 Elsevier B.V.


  • Chemodenitrification
  • Goethite
  • Infrared spectroscopy
  • Nitrite
  • Nitrous oxide
  • Redox transformation
  • Sorption

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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