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| Lotfi-kalahroodi, Elaheh; Pierson-wickmann, Anne-catherine; Guénet, Hélène; Rouxel, Olivier; Ponzevera, Emmanuel; Bouhnik-lecoz, Martine; Vantelon, Delphine; Dia, Aliou; Davranche, Mélanie. |
| Colloids have been recognized as key vectors of pollutants in aqueous environment. Amongst them, those formed by iron (Fe) and organic matter (OM) are of major importance due to their ubiquity in the surface environment and strong affinity for metals. In the recent years, Fe stable isotopes have been increasingly used to elucidate the sources and biogeochemical cycling of Fe in Earth's surface environments. In this study, we aim to elucidate (i) the possible Fe isotopic signature resulting from the Fe/OM colloid formation and (ii) the mechanisms involved in the development of such isotopic signature. For this purpose, Fe-OM associations were synthesized through binding and titration experiments. Various pH levels were used in order to study the isotope... |
| Tipo: Text |
Palavras-chave: Filtration; Size fractionation; Isotope fractionation; Colloidal; Dissolved; Fe isotopes. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00480/59174/61811.pdf |
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| Lotfi-kalahroodi, Elaheh; Pierson-wickmann, Anne-catherine; Rouxel, Olivier; Marsac, Rémi; Bouhnik-le Coz, Martine; Hanna, Khalil; Davranche, Mélanie. |
| Although redox reactions are recognized to fractionate iron (Fe) isotopes, the dominant mechanisms controlling the Fe isotope fractionation and notably the role of organic matter (OM) are still debated. Here, we demonstrate how binding to organic ligands governs Fe isotope fractionation beyond that arising from redox reactions. The reductive biodissolution of soil Fe(III) enriched the solution in light Fe isotopes, whereas, with the extended reduction, the preferential binding of heavy Fe isotopes to large biological organic ligands enriched the solution in heavy Fe isotopes. Under oxic conditions, the aggregation/sedimentation of Fe(III) nano-oxides with OM resulted in an initial enrichment of the solution in light Fe isotopes. However, heavy Fe isotopes... |
| Tipo: Text |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00677/78931/81302.pdf |
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