Does ultrafiltration kinetics bias iron isotope compositions?

Type Article
Date 2021-04
Language English
Author(s) Lotfi-Kalahroodi Elaheh1, Pierson-Wickmann Anne-Catherine1, Rouxel OlivierORCID2, Coz Martine Bouhnik-Le1, Davranche Mélanie1
Affiliation(s) 1 : Univ. Rennes, CNRS, Géosciences Rennes - UMR 6118, 35000 Rennes, France
2 : IFREMER, Unité de Géosciences Marines, 29280 Plouzané, France
Source Chemical Geology (0009-2541) (Elsevier BV), 2021-04 , Vol. 566 , P. 120082 (7p.)
DOI 10.1016/j.chemgeo.2021.120082
WOS© Times Cited 1
Keyword(s) Ultrafiltration kinetics, Speciation, Iron, Isotopic fractionation

Iron (Fe) isotopes are now recognized as useful tracers of Fe sources and biogeochemical processes in natural environments but many uncertainties remain regarding the mechanisms that control their isotopic fractionation. Ultrafiltration techniques applied to separate Fe species could potentially bias Fe isotopic compositions. Here, we investigated frontal centrifugal ultrafiltration. We have set up time-ultrafiltration experiments at low and high Fe concentrations both with and without organic matter (OM) at pH values of 1 and 6.5. The ultrafiltration impact was studied by monitoring the Fe isotope composition in the <30 kDa ultrafiltrates relative to the ultrafiltration time. No Fe isotopes bias resulted from the ultrafiltration technique regardless the Fe and OM concentrations and speciation. This work, therefore, validates the use of the frontal centrifugal ultrafiltration technique to study the signature of Fe isotopes in environmental samples composed of various Fe species sizes such as colloids, nanoparticles, clusters or soluble complexes.

Full Text
File Pages Size Access
Author's final draft 20 951 KB Open access
5 698 KB Access on demand
7 463 KB Access on demand
Top of the page