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Title: Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates

Abstract

The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe2+) and ferric (Fe3+) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic C=C, ester, phenol andmore » anomeric C (R-O-C-O-R), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. In conclusion, our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.« less

Authors:
 [1];  [2];  [3];  [2]
  1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
  2. Cornell Univ., Ithaca, NY (United States). Soil and Crop Sciences, School of Integrative Plant Science
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). National Synchrotron Light Source II (NSLS-II)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES)
OSTI Identifier:
1426466
Alternate Identifier(s):
OSTI ID: 1549526
Report Number(s):
BNL-203360-2018-JAAM
Journal ID: ISSN 0146-6380
Grant/Contract Number:  
SC0012704; AC02-98CH10886
Resource Type:
Accepted Manuscript
Journal Name:
Organic Geochemistry
Additional Journal Information:
Journal Volume: 115; Journal Issue: C; Journal ID: ISSN 0146-6380
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Iron speciation; Redox; Iron-organic matter interactions; Iron; Ferrous; Ferric; Peatlands; Spectroscopy; Multiplet calculations

Citation Formats

Bhattacharyya, Amrita, Schmidt, Michael P., Stavitski, Eli, and Martínez, Carmen Enid. Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates. United States: N. p., 2017. Web. https://doi.org/10.1016/j.orggeochem.2017.10.012.
Bhattacharyya, Amrita, Schmidt, Michael P., Stavitski, Eli, & Martínez, Carmen Enid. Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates. United States. https://doi.org/10.1016/j.orggeochem.2017.10.012
Bhattacharyya, Amrita, Schmidt, Michael P., Stavitski, Eli, and Martínez, Carmen Enid. Tue . "Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates". United States. https://doi.org/10.1016/j.orggeochem.2017.10.012. https://www.osti.gov/servlets/purl/1426466.
@article{osti_1426466,
title = {Iron speciation in peats: Chemical and spectroscopic evidence for the co-occurrence of ferric and ferrous iron in organic complexes and mineral precipitates},
author = {Bhattacharyya, Amrita and Schmidt, Michael P. and Stavitski, Eli and Martínez, Carmen Enid},
abstractNote = {The speciation of iron (Fe) in organic matter (OM)-rich environments under in situ variable redox conditions is largely unresolved. Peatlands provide a natural setting to study Fe–OM interactions. Utilizing chemical, spectroscopic and theoretical modeling approaches, we report the chemical forms, oxidation states and local coordination environment of naturally occurring Fe in the vertically redox-stratified Manning peatlands of western New York. In addition, we report dominant carbon, sulfur and nitrogen species that can potentially stabilize the various Fe species present in these peatlands. Our results provide clear direct and indirect evidence for the co-occurrence of ferrous (Fe2+) and ferric (Fe3+) iron species in peats under both oxic and anoxic conditions. Iron is mostly present within the operationally defined organic and amorphous (i.e., short range ordered, SRO) fractions; ferric iron primarily as magnetically isolated paramagnetic Fe3+ in Fe(III)-organic complexes, but also in mineral forms such as ferrihydrite; ferrous iron in tetrahedral coordination in Fe(II)-organic complexes with minor contribution from pyrite. All of the Fe species identified stabilize Fe(III) and/or Fe(II) in anoxic and oxic peats. Fundamental differences are also observed in the relative proportion of C, S and N functionalities of OM in oxic and anoxic peats. Aromatic C=C, ester, phenol and anomeric C (R-O-C-O-R), as well as thiol, sulfide and heterocyclic N functionalities are more prevalent in anoxic peats. Collectively, our experimental evidence suggests iron forms coordination complexes with O-, S- and N-containing functional groups of OM. We posit the co-occurrence of organic and mineral forms of Fe(II) and Fe(III) in both oxic and anoxic peat layers results from dynamic complexation and hydrolysis-precipitation reactions that occur under variable redox conditions. In conclusion, our findings aid in understanding the crucial role OM plays in determining Fe species in soils and sediments.},
doi = {10.1016/j.orggeochem.2017.10.012},
journal = {Organic Geochemistry},
number = C,
volume = 115,
place = {United States},
year = {2017},
month = {10}
}

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Works referenced in this record:

Revealing forms of iron in river-borne material from major tropical rivers of the Amazon Basin (Brazil)
journal, July 2004


Electron Transfer Capacities and Reaction Kinetics of Peat Dissolved Organic Matter
journal, January 2007

  • Bauer, Markus; Heitmann, Tobias; Macalady, Donald L.
  • Environmental Science & Technology, Vol. 41, Issue 1
  • DOI: 10.1021/es061323j

Carboxylate Binding in Copper Histidine Complexes in Solution and in Zeolite Y:  X- and W-band Pulsed EPR/ENDOR Combined with DFT Calculations
journal, August 2004

  • Baute, Debbie; Arieli, Dafna; Neese, Frank
  • Journal of the American Chemical Society, Vol. 126, Issue 37
  • DOI: 10.1021/ja047761c

The origin, composition, and reactivity of dissolved iron(III) complexes in coastal organic- and iron-rich sediments
journal, March 2015

  • Beckler, Jordon S.; Jones, Morris E.; Taillefert, Martial
  • Geochimica et Cosmochimica Acta, Vol. 152
  • DOI: 10.1016/j.gca.2014.12.017

Redox interactions between Fe and cysteine: Spectroscopic studies and multiplet calculations
journal, December 2013

  • Bhattacharyya, Amrita; Stavitski, Eli; Dvorak, Joseph
  • Geochimica et Cosmochimica Acta, Vol. 122
  • DOI: 10.1016/j.gca.2013.08.012

X-ray Photoelectron Spectroscopy Sulfur 2p Study of Organic Thiol and Disulfide Binding Interactions with Gold Surfaces
journal, January 1996

  • Castner, David G.; Hinds, Kenneth; Grainger, David W.
  • Langmuir, Vol. 12, Issue 21
  • DOI: 10.1021/la960465w

Solution Redox Couples for Electrochemical Energy Storage
journal, January 1981

  • Chen, Yih-Wen D.; Santhanam, K. S. V.; Bard, Allen J.
  • Journal of The Electrochemical Society, Vol. 128, Issue 7, p. 1460-1467
  • DOI: 10.1149/1.2127663

A mechanism of abiotic immobilization of nitrate in forest ecosystems: the ferrous wheel hypothesis
journal, February 2003


Multiplet effects in X-ray spectroscopy
journal, January 2005


XRD, IR and ESR study of experimental alteration of Al-nontronite into mixed-layer kaolinite/smectite
journal, December 1989


EPR and magnetic investigations on sulphides and sulphosalts [EPR and magnetic investigations on sulphides and sulphosalts]
journal, November 2002


Mössbauer spectroscopic studies of iron in organic material from natural sedimentary environments
journal, September 1979


Hard and Soft X-ray Absorption Spectroscopic Investigation of Aqueous Fe(III)−Hydroxamate Siderophore Complexes
journal, October 2005

  • Edwards, David C.; Myneni, Satish C. B.
  • The Journal of Physical Chemistry A, Vol. 109, Issue 45
  • DOI: 10.1021/jp053349n

Reduction of Nitrate By Fe2+ in Clay Minerals
journal, January 1996


The 57Fe Mössbauer parameters of pyrite and marcasite with different provenances
journal, May 1982


Ratios of ferrous to ferric iron from nanometre-sized areas in minerals
journal, December 1998

  • Garvie, Laurence A. J.; Buseck, Peter R.
  • Nature, Vol. 396, Issue 6712
  • DOI: 10.1038/25334

Physics of coal methane: decisive role of iron compounds
journal, March 2016


Copper L-edge spectral studies: a direct experimental probe of the ground-state covalency in the blue copper site in plastocyanin
journal, April 1993

  • George, Simon J.; Lowery, Michael D.; Solomon, Edward I.
  • Journal of the American Chemical Society, Vol. 115, Issue 7
  • DOI: 10.1021/ja00060a052

Performance of XPS analysis of model biochemical compounds
journal, January 1995


Interpretation of sulphur 2p XPS spectra in sulfide minerals by means ofab initio calculations
journal, February 2000


Characterization of iron-fulvic acid complexes using Mossbauer and EPR spectroscopy
journal, January 1987


Increasing pH drives organic matter solubilization from wetland soils under reducing conditions
journal, December 2009


Binding of Iron(III) to Organic Soils:  EXAFS Spectroscopy and Chemical Equilibrium Modeling
journal, February 2007

  • Gustafsson, Jon Petter; Persson, Ingmar; Kleja, Dan Berggren
  • Environmental Science & Technology, Vol. 41, Issue 4
  • DOI: 10.1021/es0615730

Assessment of the geochemical reactivity of Fe-DOM complexes in wetland sediment pore waters using a nitroaromatic probe compound
journal, March 2009

  • Hakala, J. Alexandra; Fimmen, Ryan L.; Chin, Yu-Ping
  • Geochimica et Cosmochimica Acta, Vol. 73, Issue 5
  • DOI: 10.1016/j.gca.2008.12.001

Abiotic Nitrate Reduction to Ammonium:  Key Role of Green Rust
journal, January 1996

  • Hansen, Hans Chr. B.; Koch, Christian B.; Nancke-Krogh, Hanne
  • Environmental Science & Technology, Vol. 30, Issue 6, p. 2053-2056
  • DOI: 10.1021/es950844w

Mapping the Speciation of Iron in Pseudomonas aeruginosa Biofilms Using Scanning Transmission X-ray Microscopy
journal, December 2008

  • Hunter, Ryan C.; Hitchcock, Adam P.; Dynes, James J.
  • Environmental Science & Technology, Vol. 42, Issue 23
  • DOI: 10.1021/es801642z

Organic carbon and sulphur compounds in wetland soils: insights on structure and transformation processes using K-edge XANES and NMR spectroscopy
journal, July 2003

  • Jokic, Aleksander; Cutler, Jeffrey N.; Ponomarenko, Elena
  • Geochimica et Cosmochimica Acta, Vol. 67, Issue 14
  • DOI: 10.1016/S0016-7037(03)00101-7

Mineral surfaces and soil organic matter
journal, June 2003


Coordination chemistry and hydrolysis of Fe(III) in a peat humic acid studied by X-ray absorption spectroscopy
journal, January 2010


Characterization of Iron(III) in Organic Soils Using Extended X-ray Absorption Fine Structure Spectroscopy
journal, August 2008

  • Karlsson, Torbjörn; Persson, Per; Skyllberg, Ulf
  • Environmental Science & Technology, Vol. 42, Issue 15
  • DOI: 10.1021/es800322j

XPS and 15 N NMR Study of Nitrogen Forms in Carbonaceous Solids
journal, November 2002

  • Kelemen, S. R.; Afeworki, M.; Gorbaty, M. L.
  • Energy & Fuels, Vol. 16, Issue 6
  • DOI: 10.1021/ef0200828

Speciation of Uranium in Sediments before and after In situ Biostimulation
journal, March 2008

  • Kelly, Shelly D.; Kemner, Kenneth M.; Carley, Jack
  • Environmental Science & Technology, Vol. 42, Issue 5
  • DOI: 10.1021/es071764i

Nitrogen chemical structure in petroleum asphaltene and coal by X-ray absorption spectroscopy
journal, January 1993


An Investigation of Iron(III)-Fulvic Acid Complexes by Mössbauer Spectroscopy and Chemical Methods
journal, July 1988


13C and 15N NMR spectroscopy as a tool in soil organic matter studies
journal, November 1997


Seasonal cycling of Fe in saltmarsh sediments
journal, May 1995

  • Kostka, Joel E.; Luther, George W.
  • Biogeochemistry, Vol. 29, Issue 2
  • DOI: 10.1007/BF00000230

Nitrogen K -edge XANES – an overview of reference compounds used to identify `unknown' organic nitrogen in environmental samples
journal, October 2007

  • Leinweber, Peter; Kruse, Jens; Walley, Fran L.
  • Journal of Synchrotron Radiation, Vol. 14, Issue 6
  • DOI: 10.1107/S0909049507042513

Crystal chemistry of Fe-containing sphalerites
journal, May 2003


AES and XPS spectra of sulfur in sulfur compounds
journal, April 1981


Organic Matter Mineralization with Reduction of Ferric Iron in Anaerobic Sediments
journal, January 1986


Studies on the nature of sulphur in peat humic acids from the Fraser River Delta, British Columbia
journal, March 1992


Dissolved organic Fe(III) and Fe(II) complexes in salt marsh porewaters
journal, March 1996

  • Luther, George W.; Shellenbarger, P. Ann; Brendel, Paul J.
  • Geochimica et Cosmochimica Acta, Vol. 60, Issue 6
  • DOI: 10.1016/0016-7037(95)00444-0

Local Structure of Ferrihydrite and Feroxyhite by Exafs Spectroscopy
journal, June 1993


Copper−Alumina−Organic Matter Mixed Systems: Alumina Transformation and Copper Speciation As Revealed by EPR Spectroscopy
journal, June 2008

  • Enid Martínez, Carmen; Martínez-Villegas, Nadia
  • Environmental Science & Technology, Vol. 42, Issue 12
  • DOI: 10.1021/es703206u

Biogeochemistry of Metalliferous Peats:  Sulfur Speciation and Depth Distributions of dsr AB Genes and Cd, Fe, Mn, S, and Zn in Soil Cores
journal, August 2007

  • Martínez, Carmen Enid; Yáñez, Carolina; Yoon, Soh-joung
  • Environmental Science & Technology, Vol. 41, Issue 15
  • DOI: 10.1021/es070555v

Complexation of Glyphosate and Related Ligands with Iron (III)
journal, November 1989


DITHIONITE- AND OXALATE-EXTRACTABLE Fe AND Al AS AIDS IN DIFFERENTIATING VARIOUS CLASSES OF SOILS
journal, February 1966

  • McKeague, J. A.; Day, J. H.
  • Canadian Journal of Soil Science, Vol. 46, Issue 1
  • DOI: 10.4141/cjss66-003

Controls on soil cellulose decomposition along a salinity gradient in a Phragmites australis wetland in Denmark
journal, September 1999


Synthetic coprecipitates of exopolysaccharides and ferrihydrite. Part I: Characterization
journal, February 2008

  • Mikutta, Christian; Mikutta, Robert; Bonneville, Steeve
  • Geochimica et Cosmochimica Acta, Vol. 72, Issue 4
  • DOI: 10.1016/j.gca.2007.11.035

Insights into iron sources and pathways in the Amazon River provided by isotopic and spectroscopic studies
journal, February 2015

  • Mulholland, Daniel Santos; Poitrasson, Franck; Boaventura, Geraldo Resende
  • Geochimica et Cosmochimica Acta, Vol. 150
  • DOI: 10.1016/j.gca.2014.12.004

Amino acid complexes of iron. I. Iron(II) complexes of thioglycollic acid, L-cysteine and related ligands
journal, January 1975

  • Murray, Ks; Newman, Pj
  • Australian Journal of Chemistry, Vol. 28, Issue 4
  • DOI: 10.1071/CH9750773

Nitrite Reduction by Siderite
journal, July 2008

  • Rakshit, Sudipta; Matocha, Christopher J.; Coyne, Mark S.
  • Soil Science Society of America Journal, Vol. 72, Issue 4
  • DOI: 10.2136/sssaj2007.0296

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


Electron paramagnetic resonance, optical absorption and Raman spectral studies on a pyrite/chalcopyrite mineral
journal, October 2012

  • Udayabhaskar Reddy, G.; Seshamaheswaramma, K.; Nakamura, Yoshinobu
  • Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, Vol. 96
  • DOI: 10.1016/j.saa.2012.04.093

The fate of nitrogen is linked to iron(II) availability in a freshwater lake sediment
journal, May 2017


The identification of sulphide minerals by infra-red spectroscopy
journal, June 1978


The CTM4XAS program for EELS and XAS spectral shape analysis of transition metal L edges
journal, October 2010


Stable free radicals in soil humic acid
journal, May 1962


Ferrozine---a new spectrophotometric reagent for iron
journal, June 1970

  • Stookey, Lawrence L.
  • Analytical Chemistry, Vol. 42, Issue 7, p. 779-781
  • DOI: 10.1021/ac60289a016

Redox properties of standard humic acids
journal, August 2001


The cycling of iron in natural environments: Considerations based on laboratory studies of heterogeneous redox processes
journal, August 1992


Reactivity of Freshly Formed Fe(III) in Synthetic Solutions and (Pore)Waters:  Voltammetric Evidence of an Aging Process
journal, June 2000

  • Taillefert, M.; Bono, A. B.; Luther, G. W.
  • Environmental Science & Technology, Vol. 34, Issue 11
  • DOI: 10.1021/es990120a

Colloid Mobilization During Soil Iron Redox Oscillations
journal, September 2006

  • Thompson, Aaron; Chadwick, Oliver A.; Boman, Sarah
  • Environmental Science & Technology, Vol. 40, Issue 18
  • DOI: 10.1021/es061203b

Preservation of iron(II) by carbon-rich matrices in a hydrothermal plume
journal, February 2009

  • Toner, Brandy M.; Fakra, Sirine C.; Manganini, Steven J.
  • Nature Geoscience, Vol. 2, Issue 3
  • DOI: 10.1038/ngeo433

EXAFS Study on the Reactions between Iron and Fulvic Acid in Acid Aqueous Solutions
journal, April 2008

  • van Schaik, Joris W. J.; Persson, Ingmar; Kleja, Dan Berggren
  • Environmental Science & Technology, Vol. 42, Issue 7
  • DOI: 10.1021/es072092z

Magnetic and EPR study of ferric green rust- and ferrihydrite-coated sand prepared by different synthesis routes
journal, November 2009


A Multiplet Analysis of Fe K-Edge 1s → 3d Pre-Edge Features of Iron Complexes
journal, July 1997

  • Westre, Tami E.; Kennepohl, Pierre; DeWitt, Jane G.
  • Journal of the American Chemical Society, Vol. 119, Issue 27
  • DOI: 10.1021/ja964352a

Functionalized graphene sheets coordinating metal cations
journal, August 2014


Natural zinc enrichment in peatlands: Biogeochemistry of ZnS formation
journal, May 2012

  • Yoon, Soh-joung; Yáñez, Carolina; Bruns, Mary Ann
  • Geochimica et Cosmochimica Acta, Vol. 84
  • DOI: 10.1016/j.gca.2012.01.022

X-ray Absorption Spectroscopy of the Nucleotide Bases at the Carbon, Nitrogen, and Oxygen K-Edges
journal, November 2008

  • Zubavichus, Yan; Shaporenko, Andrey; Korolkov, Vladimir
  • The Journal of Physical Chemistry B, Vol. 112, Issue 44
  • DOI: 10.1021/jp802453u

NEXAFS spectroscopy of biological molecules: From amino acids to functional proteins
journal, May 2009

  • Zubavichus, Y.; Shaporenko, A.; Grunze, M.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 603, Issue 1-2
  • DOI: 10.1016/j.nima.2008.12.171

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    Cryptic Cycling of Complexes Containing Fe(III) and Organic Matter by Phototrophic Fe(II)-Oxidizing Bacteria
    journal, February 2019

    • Peng, Chao; Bryce, Casey; Sundman, Anneli
    • Applied and Environmental Microbiology, Vol. 85, Issue 8
    • DOI: 10.1128/aem.02826-18

    Mineral colloids mediate organic carbon accumulation in a temperate forest Spodosol: depth-wise changes in pore water chemistry
    journal, October 2018

    • Bazilevskaya, Ekaterina; Archibald, Douglas D.; Martínez, Carmen Enid
    • Biogeochemistry, Vol. 141, Issue 1
    • DOI: 10.1007/s10533-018-0504-4

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    journal, January 2019