Please use this identifier to cite or link to this item: http://hdl.handle.net/1893/36936
Appears in Collections:Biological and Environmental Sciences Journal Articles
Peer Review Status: Refereed
Title: Reduction Pathway-Dependent Formation of Reactive Fe(II) Sites in Clay Minerals
Author(s): Rothwell, Katherine A.
Pentrak, Martin P.
Pentrak, Linda A.
Stucki, Joseph W.
Neumann, Anke
Contact Email: katherine.rothwell@stir.ac.uk
Issue Date: 18-Jul-2023
Date Deposited: 21-Mar-2025
Citation: Rothwell KA, Pentrak MP, Pentrak LA, Stucki JW & Neumann A (2023) Reduction Pathway-Dependent Formation of Reactive Fe(II) Sites in Clay Minerals. <i>Environmental Science & Technology</i>, 57 (28), pp. 10231-10241. https://doi.org/10.1021/acs.est.3c01655
Abstract: Structural Fe in clay minerals is an important, potentially renewable source of electron equivalents for contaminant reduction, yet our knowledge of how clay mineral Fe reduction pathways and Fe reduction extent affect clay mineral Fe(II) reactivity is limited. Here, we used a nitroaromatic compound (NAC) as a reactive probe molecule to assess the reactivity of chemically reduced (dithionite) and Fe(II)-reduced nontronite across a range of reduction extents. We observed biphasic transformation kinetics for all nontronite reduction extents of ≥5% Fe(II)/Fe(total) regardless of the reduction pathway, indicating that two Fe(II) sites of different reactivities form in nontronite at environmentally relevant reduction extents. At even lower reduction extents, Fe(II)-reduced nontronite completely reduced the NAC whereas dithionite-reduced nontronite could not. Our 57Fe Mössbauer spectroscopy, ultraviolet−visible spectroscopy, and kinetic modeling results suggest that the highly reactive Fe(II) entities likely comprise di/trioctahedral Fe(II) domains in the nontronite structure regardless of the reduction mechanism. However, the second Fe(II) species, of lower reactivity, varies and for Fe(II)-reacted NAu-1 likely comprises Fe(II) associated with an Fe-bearing precipitate formed during electron transfer from aqueous to nontronite Fe. Both our observation of biphasic reduction kinetics and the nonlinear relationship of rate constant and clay mineral reduction potential EH have major implications for contaminant fate and remediation.
DOI Link: 10.1021/acs.est.3c01655
Rights: Copyright © 2023 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0 .
Licence URL(s): http://creativecommons.org/licenses/by/4.0/

Files in This Item:
File Description SizeFormat 
rothwell-et-al-2023-reduction-pathway-dependent-formation-of-reactive-fe(ii)-sites-in-clay-minerals.pdfFulltext - Published Version2.57 MBAdobe PDFView/Open



This item is protected by original copyright



A file in this item is licensed under a Creative Commons License Creative Commons

Items in the Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

The metadata of the records in the Repository are available under the CC0 public domain dedication: No Rights Reserved https://creativecommons.org/publicdomain/zero/1.0/

If you believe that any material held in STORRE infringes copyright, please contact library@stir.ac.uk providing details and we will remove the Work from public display in STORRE and investigate your claim.