1. Molecular environment of iodine in naturally iodinated humic substances: Insight from X-ray absorption spectroscopy
- Author
-
Florence Mercier-Bion, Nicole Barré, Pascal E. Reiller, Michel L. Schlegel, Valérie Moulin, Laboratoire de Réactivité des Surfaces et des Interfaces (LRSI), Département de Physico-Chimie (DPC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire de Spéciation des Radionucléides et des Molécules (LSRM), Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement (LAMBE), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université d'Évry-Val-d'Essonne (UEVE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CEA-Direction de l'Energie Nucléaire (CEA-DEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction de l'Energie Nucléaire (CEA-DEN), Laboratoire Analyse et Modélisation pour la Biologie et l'Environnement (LAMBE - UMR 8587), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Université d'Évry-Val-d'Essonne (UEVE)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
- Subjects
010504 meteorology & atmospheric sciences ,Absorption spectroscopy ,Inorganic chemistry ,Analytical chemistry ,chemistry.chemical_element ,010501 environmental sciences ,Iodine ,01 natural sciences ,X-ray photoelectron spectroscopy ,[CHIM.ANAL]Chemical Sciences/Analytical chemistry ,Geochemistry and Petrology ,SPECIATION ,0105 earth and related environmental sciences ,X-ray absorption spectroscopy ,Extended X-ray absorption fine structure ,[CHIM.ORGA]Chemical Sciences/Organic chemistry ,Chemistry ,BOOM CLAY ,MASS-SPECTROMETRY ,XANES ,XANES SPECTROSCOPY ,WEATHERING PLANT-MATERIAL ,SOILS ,FULVIC-ACIDS ,ORGANIC-MATTER ,FUEL REPROCESSING PLANT ,13. Climate action ,Covalent bond ,[SDE]Environmental Sciences ,[PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph] ,Absorption (chemistry) ,FINE-STRUCTURE - Abstract
International audience; The molecular environment of iodine in reference inorganic and organic compounds, and in dry humic and fulvic acids (HAs and FAs) extracted from subsurface and deep aquifers was probed by iodine L 3-edge X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) of iodine spectra from HAs and FAs resembled those of organic references and displayed structural features consistent with iodine forming covalent bonds with organic molecules. Simulation of XANES spectra by linear combination of reference spectra suggested the predominance of iodine forming covalent bonds to aromatic rings (aromatic-bound iodine). Comparison of extended X-ray absorption fine structure (EXAFS) spectra of reference and samples further showed that iodine was surrounded by carbon shells at distances comparables to those for references containing aromatic-bound iodine. Quantitative analysis of EXAFS spectra indicated that iodine was bound to about one carbon at a distance d (I–C) of 2.01(4)–2.04(9) A ˚ , which was comparable to the distances observed for aromatic-bound iodine in references (1.99(1)–2.07(6) A ˚), and significantly shorter than that observed for aliphatic-bound iodine (2.15(2)–2.16(2) A ˚). These results are in agreement with previous conclusions from X-ray photoelectron spectros-copy and from electrospray ionization mass spectrometry. These results collectively suggest that the aromatic-bound iodine is stable in the various aquifers of this study.
- Published
- 2006
- Full Text
- View/download PDF