Red-ox speciation and mixing state of iron in individual African dust particles
2012
Deboudt, Karine | Gloter, Alexandre | Mussi, Alexandre | Flament, Pascal | Laboratoire de Physico-Chimie de l'Atmosphère (LPCA) ; Université du Littoral Côte d'Opale (ULCO) | Laboratoire de Physique des Solides - STEM (LPS) ; Laboratoire de Physique des Solides (LPS) ; Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) | Unité Matériaux et Transformations - UMR 8207 (UMET) ; Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut de Chimie - CNRS Chimie (INC-CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS) | European Community (EC) | "Action Programmee Interorganismes" API-AMMA | "Federation de Recherche CNRS 1818" | Region Hauts-de-France | Ministsre de l'Enseignement Superieur et de la Recherche Centre National de la Recherche Scientifique (CNRS) European Union (EU) Region Hauts-de-FranceRegion Ile-de-France European Union (EU) | Centre National de la Recherche Scientifique (CNRS) Laboratoire d'Optique Atmospherique Universite des Scienes et Technologies de Lille
International audience
Show more [+] Less [-]English. The Fe distribution in African dust particles collected in Senegal (North-Western Africa) during the African Monsoon Multidisciplinary Analysis Special Observation Period 0 (AMMA-"SOP 0,"February 2006) was assessed using individual particle analysis ( Scanning and Transmission Electron Microscopy respectively equipped with X-ray Spectrometry (SEM-EDX) and Electron Energy Loss Spectrometry (TEM-EELS)). Senegal is not a dust source area; the chemical composition of collected dusts indicates that they originate primarily in the North-Western Sahara, which is consistent with previous studies of the area. Fe can be present inside dust particles as a substitution element in the crystalline lattice of aluminosilicate, but a high proportion (62%) of aluminosilicate Fe-containing particles are also found as an internal mixture of aluminosilicate with Fe oxide grains ( including both oxide and hydroxide species). The 3D structure of such particles obtained by tomography reveals that these Fe-rich inclusions are often found at the surface of aluminosilicate particles but that some are also included inside particles. These Fe oxide grains can result from crustal earth or atmospheric processes during long-range transport. Fe-III is dominant in both the aluminosilicate matrix and the Fe oxide grains (Fe-III/Sigma Fe ratio = 76.8% and 90.0%, respectively, on average), with notable heterogeneities of Fe valence inside grains at a nanometer scale.
Show more [+] Less [-]AGROVOC Keywords
Bibliographic information
This bibliographic record has been provided by Institut national de la recherche agronomique