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Title: “Switching on” iron in clay minerals

Abstract

Being the fourth most abundant element in the Earth’s crust, iron (Fe) is a key player in myriad biogeochemical processes. Iron that resides in clay mineral structures undergoes cycling between Fe(II) and Fe(III). This iron comprises a large redox-active pool in surface environments, controlling the fate and transport of nutrients and contaminants. The electron transfer involving this iron species is poorly understood. We observe that Fe(III) in clay minerals is not redox active, unless a minor amount of Fe(II) is introduced into the predominantly-Fe(III) structure. These “activated” clay minerals are redox-active both in the presence and absence of oxygen. In the presence of oxygen, Fe(II) catalyzes the production of reactive oxygen species; however, the oxidation pathway in the absence of oxygen is unknown. Here we show that under oxygen-free conditions, the redox-active species in clay minerals is FeII-O-FeIII moiety at the edge site. Our ab initio calculations illustrate that desorption of water from an FeII-O-FeIII site in clay mineral requires less energy, compared to an FeIII-O-FeIII site. We propose that this lower barrier for the desorption of water increases the apparent kinetics of redox reactions on clay mineral surfaces.

Authors:
 [1]; ORCiD logo [2];  [3];  [1]
  1. Sandia National Laboratory
  2. BATTELLE (PACIFIC NW LAB)
  3. Sandia National Laboratories
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1567049
Report Number(s):
PNNL-SA-139445
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Environmental Science Nano
Additional Journal Information:
Journal Volume: 6; Journal Issue: 6
Country of Publication:
United States
Language:
English

Citation Formats

Ilgen, Anastasia G., Kukkadapu, Ravi K., Leung, Kevin, and Washington, Rachel E. “Switching on” iron in clay minerals. United States: N. p., 2019. Web. doi:10.1039/c9en00228f.
Ilgen, Anastasia G., Kukkadapu, Ravi K., Leung, Kevin, & Washington, Rachel E. “Switching on” iron in clay minerals. United States. https://doi.org/10.1039/c9en00228f
Ilgen, Anastasia G., Kukkadapu, Ravi K., Leung, Kevin, and Washington, Rachel E. Mon . "“Switching on” iron in clay minerals". United States. https://doi.org/10.1039/c9en00228f.
@article{osti_1567049,
title = {“Switching on” iron in clay minerals},
author = {Ilgen, Anastasia G. and Kukkadapu, Ravi K. and Leung, Kevin and Washington, Rachel E.},
abstractNote = {Being the fourth most abundant element in the Earth’s crust, iron (Fe) is a key player in myriad biogeochemical processes. Iron that resides in clay mineral structures undergoes cycling between Fe(II) and Fe(III). This iron comprises a large redox-active pool in surface environments, controlling the fate and transport of nutrients and contaminants. The electron transfer involving this iron species is poorly understood. We observe that Fe(III) in clay minerals is not redox active, unless a minor amount of Fe(II) is introduced into the predominantly-Fe(III) structure. These “activated” clay minerals are redox-active both in the presence and absence of oxygen. In the presence of oxygen, Fe(II) catalyzes the production of reactive oxygen species; however, the oxidation pathway in the absence of oxygen is unknown. Here we show that under oxygen-free conditions, the redox-active species in clay minerals is FeII-O-FeIII moiety at the edge site. Our ab initio calculations illustrate that desorption of water from an FeII-O-FeIII site in clay mineral requires less energy, compared to an FeIII-O-FeIII site. We propose that this lower barrier for the desorption of water increases the apparent kinetics of redox reactions on clay mineral surfaces.},
doi = {10.1039/c9en00228f},
url = {https://www.osti.gov/biblio/1567049}, journal = {Environmental Science Nano},
number = 6,
volume = 6,
place = {United States},
year = {2019},
month = {7}
}

Works referenced in this record:

Reactivity of Fe(II) Species Associated with Clay Minerals
journal, February 2003


Heterogeneous reduction of Tc(VII) by Fe(II) at the solid–water interface
journal, March 2008


Partitioning of Fe(II) in reduced nontronite (NAu-2) to reactive sites: reactivity in terms of Tc(VII) reduction
journal, April 2008


Interaction between aqueous chromium solutions and layer silicates
journal, October 2000


Role of structural Fe in nontronite NAu-1 and dissolved Fe(II) in redox transformations of arsenic and antimony
journal, October 2012


Production of Abundant Hydroxyl Radicals from Oxygenation of Subsurface Sediments
journal, December 2015


Mechanisms of electron transfer from structrual Fe(II) in reduced nontronite to oxygen for production of hydroxyl radicals
journal, February 2018


Spectroscopic Investigations of Fe 2+ Complexation on Nontronite Clay
journal, January 2007


Oxidation-reduction mechanism of iron in dioctahedral smectites: II. Crystal chemistry of reduced Garfield nontronite
journal, January 2000


Oxidation-reduction mechanism of iron in dioctahedral smectites: I. Crystal chemistry of oxidized reference nontronites
journal, January 2000


Site Occupancies by Iron in Nontronites
journal, April 2002


Synthesis and characterization of redox-active ferric nontronite
journal, October 2017


Redox Properties of Structural Fe in Clay Minerals: 3. Relationships between Smectite Redox and Structural Properties
journal, November 2013


Reduction of Nitroaromatic Compounds by Fe(II) Species Associated with Iron-Rich Smectites
journal, January 2006


Redox Properties of Structural Fe in Clay Minerals. 1. Electrochemical Quantification of Electron-Donating and -Accepting Capacities of Smectites
journal, August 2012


Redox Properties of Structural Fe in Clay Minerals. 2. Electrochemical and Spectroscopic Characterization of Electron Transfer Irreversibility in Ferruginous Smectite, SWa-1
journal, August 2012


Control of Fe(III) site occupancy on the rate and extent of microbial reduction of Fe(III) in nontronite
journal, December 2005


Spectroscopic Evidence for Fe(II)–Fe(III) Electron Transfer at Clay Mineral Edge and Basal Sites
journal, March 2013


Spectroscopic Evidence for Interfacial Fe(II)−Fe(III) Electron Transfer in a Clay Mineral
journal, January 2011


Insights into the Mechanism of Fe(II) Adsorption and Oxidation at Fe–Clay Mineral Surfaces from First-Principles Calculations
journal, October 2013


Redox Transformations of As and Se at the Surfaces of Natural and Synthetic Ferric Nontronites: Role of Structural and Adsorbed Fe(II)
journal, September 2017


Electrochemical trapping of metastable Mn 3+ ions for activation of MnO 2 oxygen evolution catalysts
journal, May 2018


Preparation and Handling of Dithionite-Reduced Smectite Suspensions
journal, January 1984


ATHENA , ARTEMIS , HEPHAESTUS : data analysis for X-ray absorption spectroscopy using IFEFFIT
journal, June 2005


IFEFFIT  : interactive XAFS analysis and FEFF fitting
journal, March 2001


Near-edge x-ray-absorption fine structure of Pb: A comparison of theory and experiment
journal, June 1993


Multiple-scattering calculations of x-ray-absorption spectra
journal, July 1995


Voigt-based methods for arbitrary-shape static hyperfine parameter distributions in Mössbauer spectroscopy
journal, May 1991


Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set
journal, October 1996


Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set
journal, July 1996


From ultrasoft pseudopotentials to the projector augmented-wave method
journal, January 1999


Why does the B3LYP hybrid functional fail for metals?
journal, July 2007


Generalized Gradient Approximation Made Simple
journal, October 1996


Influence of Coprecipitated Organic Matter on Fe 2+ (aq) -Catalyzed Transformation of Ferrihydrite: Implications for Carbon Dynamics
journal, July 2015


Redox Fluctuations Control the Coupled Cycling of Iron and Carbon in Tropical Forest Soils
journal, November 2018


Electron Exchange and Conduction in Nontronite from First-Principles
journal, January 2013


Quantifying surface areas of clays by atomic force microscopy
journal, May 2002


Redox Transformation of Arsenic by Fe(II)-Activated Goethite (α-FeOOH)
journal, January 2010


Effects of pH, dissolved oxygen, and aqueous ferrous iron on the adsorption of arsenic to lepidocrocite
journal, June 2015


Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U study
journal, January 1998