skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The Role of Defects in Fe(II)–Goethite Electron Transfer

Abstract

Despite accumulating experimental evidence for Fe(II)-Fe(III) oxide electron transfer, computational chemical calculations suggest that oxidation of sorbed Fe(II) is not energetically feasible unless defects are present. Here we used isotope specific 57Fe Mössbauer spectroscopy to investigate whether Fe(II)-goethite electron transfer is influenced by defects. Specifically, we heated the mineral to try to anneal the goethite surface and ground goethite to try to create defects. We found that heating goethite results in less oxidation of sorbed Fe(II) by goethite. When goethite was re-ground after heating, electron transfer was partially restored. X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) of heated and ground goethite confirm that heating and grinding alter the surface structure of the goethite. We propose that the heating process annealed the surface and decreased the number of sites where electron transfer could occur. Our experimental findings suggest that surface defects play an important role in Fe(II)-goethite electron transfer as suggested by computational calculations. Our finding that defects influence heterogeneous Fe(II)-goethite electron transfer has important implications for Fe(II) driven recrystallization of Fe oxides, as well as X and Y.

Authors:
ORCiD logo [1]; ORCiD logo [1];  [2];  [3]; ORCiD logo [3];  [4]; ORCiD logo [3];  [1]
  1. Department of Civil and Environmental Engineering, University of Iowa, Iowa City, Iowa 52242, United States
  2. School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
  3. Pacific Northwest National Laboratory, Richland, Washington 99352, United States
  4. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1455251
Report Number(s):
PNNL-SA-131667
Journal ID: ISSN 0013-936X; 47824; KC0302060
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Environmental Science and Technology; Journal Volume: 52; Journal Issue: 5
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Notini, Luiza, Latta, Drew E., Neumann, Anke, Pearce, Carolyn I., Sassi, Michel, N’Diaye, Alpha T., Rosso, Kevin M., and Scherer, Michelle M. The Role of Defects in Fe(II)–Goethite Electron Transfer. United States: N. p., 2018. Web. doi:10.1021/acs.est.7b05772.
Notini, Luiza, Latta, Drew E., Neumann, Anke, Pearce, Carolyn I., Sassi, Michel, N’Diaye, Alpha T., Rosso, Kevin M., & Scherer, Michelle M. The Role of Defects in Fe(II)–Goethite Electron Transfer. United States. doi:10.1021/acs.est.7b05772.
Notini, Luiza, Latta, Drew E., Neumann, Anke, Pearce, Carolyn I., Sassi, Michel, N’Diaye, Alpha T., Rosso, Kevin M., and Scherer, Michelle M. Tue . "The Role of Defects in Fe(II)–Goethite Electron Transfer". United States. doi:10.1021/acs.est.7b05772.
@article{osti_1455251,
title = {The Role of Defects in Fe(II)–Goethite Electron Transfer},
author = {Notini, Luiza and Latta, Drew E. and Neumann, Anke and Pearce, Carolyn I. and Sassi, Michel and N’Diaye, Alpha T. and Rosso, Kevin M. and Scherer, Michelle M.},
abstractNote = {Despite accumulating experimental evidence for Fe(II)-Fe(III) oxide electron transfer, computational chemical calculations suggest that oxidation of sorbed Fe(II) is not energetically feasible unless defects are present. Here we used isotope specific 57Fe Mössbauer spectroscopy to investigate whether Fe(II)-goethite electron transfer is influenced by defects. Specifically, we heated the mineral to try to anneal the goethite surface and ground goethite to try to create defects. We found that heating goethite results in less oxidation of sorbed Fe(II) by goethite. When goethite was re-ground after heating, electron transfer was partially restored. X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) of heated and ground goethite confirm that heating and grinding alter the surface structure of the goethite. We propose that the heating process annealed the surface and decreased the number of sites where electron transfer could occur. Our experimental findings suggest that surface defects play an important role in Fe(II)-goethite electron transfer as suggested by computational calculations. Our finding that defects influence heterogeneous Fe(II)-goethite electron transfer has important implications for Fe(II) driven recrystallization of Fe oxides, as well as X and Y.},
doi = {10.1021/acs.est.7b05772},
journal = {Environmental Science and Technology},
number = 5,
volume = 52,
place = {United States},
year = {Tue Feb 06 00:00:00 EST 2018},
month = {Tue Feb 06 00:00:00 EST 2018}
}