Effects of Fe competition on REE binding to humic acid: Origin of REE pattern variability in organic waters
In: Chemical Geology, Jg. 342 (2013-03-01), S. 119-127
Online
unknown
Zugriff:
International audience; Competitivemechanisms between rare earth elements (REE) and iron (Fe) for humic acid (HA) bindingwere investigated by coupling laboratory experiments and modeling calculations using PHREEQC/Model VI. This study aims, firstly, at determining the effect of Fe on REE-HA binding, in order to explain the REE pattern variability observed in natural organic-rich waters. Secondly, it has previously been shown that light and heavy REE (Land HREE) speciation with HA molecules differ with pH. Therefore, REE-HA complexation patterns have been used as a probe of Fe-HA binding mechanisms. At pH 3, i.e. pH conditions at which Fe3+ binds to HA, Fe is shown to be a strong competitor for heavy REE (HREE), suggesting that Fe3+ has a marked affinity for the few strong HA multidentate sites. At pH 6, i.e. under pH conditions atwhich hydrolyzed Fe species bind to HA, Fe appears to compete equally for every REE, thereby indicating that Fe has the samerelative affinity for carboxylic and phenolic HA sites as LREE and HREE, respectively. Fractionation of REE in organic-rich natural waters depends mainly on the coupling of two factors: (i) the total dissolved metal concentration (i.e. the HA metal loading) and (ii) the competition between REE and major cations (i.e. Fe and Al). The pH, which regulates the speciation of these competitive metals, is, therefore, indirectly the main controlling factor of REE fractionation in organic-rich waters.
Titel: |
Effects of Fe competition on REE binding to humic acid: Origin of REE pattern variability in organic waters
|
---|---|
Autor/in / Beteiligte Person: | Dia, Aline ; Briant, Nicolas ; Davranche, Mélanie ; Gruau, Gérard ; Marsac, Rémi ; Pédrot, Mathieu ; Martine Le Coz-Bouhnik ; Géosciences Rennes (GR) ; Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1) ; Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES) ; Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR) ; Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS) |
Link: | |
Zeitschrift: | Chemical Geology, Jg. 342 (2013-03-01), S. 119-127 |
Veröffentlichung: | Elsevier BV, 2013 |
Medientyp: | unknown |
ISSN: | 0009-2541 (print) |
DOI: | 10.1016/j.chemgeo.2013.01.020 |
Schlagwort: |
|
Sonstiges: |
|