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Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5

Naturally occurring goethites often show Al for Fe substitution approaching 33 mol% Al. This substitution has potential to influence the rate of goethite dissolution and therefore the supply of bioavailable Fe. Siderophores such as ferrichrome and enterobactin have considerable potential to dissolve...

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Autores principales: Dubbin, William E., Bullough, Florence
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Netherlands 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175686/
https://www.ncbi.nlm.nih.gov/pubmed/32355452
http://dx.doi.org/10.1007/s10498-016-9304-4
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author Dubbin, William E.
Bullough, Florence
author_facet Dubbin, William E.
Bullough, Florence
author_sort Dubbin, William E.
collection PubMed
description Naturally occurring goethites often show Al for Fe substitution approaching 33 mol% Al. This substitution has potential to influence the rate of goethite dissolution and therefore the supply of bioavailable Fe. Siderophores such as ferrichrome and enterobactin have considerable potential to dissolve Fe from Fe(3+) rich minerals, including Al-substituted goethites. Here, we show that Al substitution in synthetic goethites (0.021 ≥ x ≥ 0.098) gives rise to a significant increase in both ferrichrome- and enterobactin-mediated dissolution rates. In the presence of ferrichrome, Al-goethite (x = 0.033) yields a dissolution rate of 19.0 × 10(−3) µmol m(−2) h(−1), nearly twice that of pure goethite, whereas dissolution of the most highly substituted Al-goethite (x = 0.098) is 36.9 × 10(−3) µmol m(−2) h(−1), more than threefold greater than the pure mineral. Similarly, in the presence of enterobactin, the dissolution rate of Al-goethite increases with increasing Al substitution. Ferrichrome is a less effective ligand than enterobactin in its dissolution of both pure goethite and the range of Al-goethites, an observation we ascribe to the lower affinity of the hydroxamate functional groups of ferrichrome for both Fe(3+) and Al(3+). Despite greater affinity of both ferrichrome and enterobactin for Fe(3+) over Al(3+), we observe a broadly congruent dissolution of all our Al-goethites.
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spelling pubmed-71756862020-04-28 Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5 Dubbin, William E. Bullough, Florence Aquat Geochem Original Article Naturally occurring goethites often show Al for Fe substitution approaching 33 mol% Al. This substitution has potential to influence the rate of goethite dissolution and therefore the supply of bioavailable Fe. Siderophores such as ferrichrome and enterobactin have considerable potential to dissolve Fe from Fe(3+) rich minerals, including Al-substituted goethites. Here, we show that Al substitution in synthetic goethites (0.021 ≥ x ≥ 0.098) gives rise to a significant increase in both ferrichrome- and enterobactin-mediated dissolution rates. In the presence of ferrichrome, Al-goethite (x = 0.033) yields a dissolution rate of 19.0 × 10(−3) µmol m(−2) h(−1), nearly twice that of pure goethite, whereas dissolution of the most highly substituted Al-goethite (x = 0.098) is 36.9 × 10(−3) µmol m(−2) h(−1), more than threefold greater than the pure mineral. Similarly, in the presence of enterobactin, the dissolution rate of Al-goethite increases with increasing Al substitution. Ferrichrome is a less effective ligand than enterobactin in its dissolution of both pure goethite and the range of Al-goethites, an observation we ascribe to the lower affinity of the hydroxamate functional groups of ferrichrome for both Fe(3+) and Al(3+). Despite greater affinity of both ferrichrome and enterobactin for Fe(3+) over Al(3+), we observe a broadly congruent dissolution of all our Al-goethites. Springer Netherlands 2016-10-12 2017 /pmc/articles/PMC7175686/ /pubmed/32355452 http://dx.doi.org/10.1007/s10498-016-9304-4 Text en © The Author(s) 2016 Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
spellingShingle Original Article
Dubbin, William E.
Bullough, Florence
Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5
title Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5
title_full Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5
title_fullStr Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5
title_full_unstemmed Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5
title_short Dissolution of Al-Substituted Goethite in the Presence of Ferrichrome and Enterobactin at pH 6.5
title_sort dissolution of al-substituted goethite in the presence of ferrichrome and enterobactin at ph 6.5
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7175686/
https://www.ncbi.nlm.nih.gov/pubmed/32355452
http://dx.doi.org/10.1007/s10498-016-9304-4
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