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4. X-ray phase contrast tomography for the investigation of amyotrophic lateral sclerosis

Author

Provinciali, G, Pieroni, N, Bukreeva, I, Fratini, M, Massimi, L, Maugeri, L, Palermo, F, Bardelli, F, Mittone, A, Bravin, A, Gigli, G, Gentile, F, Fossaghi, A, Riva, N, Quattrini, A, Cedola, A, Provinciali G. B., Pieroni N., Bukreeva I., Fratini M., Massimi L., Maugeri L., Palermo F., Bardelli F., Mittone A., Bravin A., Gigli G., Gentile F., Fossaghi A., Riva N., Quattrini A., Cedola A., Provinciali, G, Pieroni, N, Bukreeva, I, Fratini, M, Massimi, L, Maugeri, L, Palermo, F, Bardelli, F, Mittone, A, Bravin, A, Gigli, G, Gentile, F, Fossaghi, A, Riva, N, Quattrini, A, Cedola, A, Provinciali G. B., Pieroni N., Bukreeva I., Fratini M., Massimi L., Maugeri L., Palermo F., Bardelli F., Mittone A., Bravin A., Gigli G., Gentile F., Fossaghi A., Riva N., Quattrini A., and Cedola A.

Abstract

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder affecting motor neurons. Pre-clinical studies drive the development of animal models that well mimic ALS disorder and enable both the dissection of disease processes and an early assessment of therapy efficacy. A comprehensive knowledge of neuronal and vascular lesions in the brain and spinal cord is an essential factor to understand the development of the disease. Spatial resolution and bidimensional imaging are important drawbacks limiting current neuroimaging tools, while neuropathology relies on protocols that may alter tissue chemistry and structure. In contrast, recent ex vivo studies in mice demonstrated that X-ray phase-contrast tomography enables study of the 3D distribution of both vasculature and neuronal networks, without sample sectioning or use of staining. Here we present our findings on ex vivo SOD1G93A ALS mice spinal cord at a micrometric scale. An unprecedented direct quantification of neuro-vascular alterations at different stages of the disease is shown.

Published
2020

9. A study of radicals in industrial raw cristobalite powders

Author

DI BENEDETTO, F., Bardelli, F., Belluso, E., Buccianti, A., Capacci, F., Capella, S., Ciuffi, B., D'Acapito, F., Giaccherini, A., LA BELLA, M., Lepore, G. O., Montegrossi, G., Moretti, M., Osculati, A., Pardi, L., Poli, C., Romanelli, M., Visona, S., Zoleo, A., and Arcangeli, G.

Published
2021

13. Abstracts of posters

Author

Suffisseau L., Taugourdeau M. C., Goldstein F. W., Mainardi J. L., Larrouturou Ph., Romero, M., Cervino, A. R., Albertone, G., Di Pasquale, R., Venturini, F., Congedo, R., Benettolo, F., Pistolesi, C., Olivato, R., Casasin T., Agusti C., Gurrera M. T., Fabregas X., Rizo A., Badia J. M., Santa-Olalla M., Marini, P., Rampazzo, R., Scroccaro, G., Dell'Aera, M., Luzzi, R., Ciccarone, G., Martinet, N., Beney, J., Marty, S., Reymond, J. -Ph., Cairns, Chris, Morgutti M., Posco M., Moltempi M., Lonqhini P., Rossignoli A., Rihet, P., Carles, G., Braguer, D., Azulay, J. P., Pouget, J., Pelletier, J., Crevat, A., Past.o, L., Barroso, E., Pujol, R., Ferrer, I., Ibars, M., Llop, J. M., Frankfort, Ellen, van Dongen, Robert T. M., Hekster, Yechiel A., Kart, T., Rasmussen, M., Horn, A., Wested, L., Gagyi, O., Markó, E., Regazzi M. B., Martinelli L., Goggi C., Bellotti E., Molinaro M., Rinaldi M., Gavazzi A., Buggia I., Daneri A., Guarnone E., Bascapē V., Viganô M., Lazzaro, A., Palozzo, A., Banfi R., Borselli G., Fabbiani P., Marinai C., Delorme, J., Tubiana, N., Buck, M., Chinot, O., De Wever, C., Robays, H., Montoro J. B., Flores G., Juárez J. C., Juste C., Jardí R., Altisent C., Tusell J. M., Arpinelli, F., De Carli, G., Olivieri, A., Recchia, G., Rossignoli A., Longhini P., La Guidara C., Russo B., Moltempi M., Tamés, M. J., Cajaraville, G., Ponz, L., Echaniz, E., Garcia, B., van Mil, J. W. Foppe, Leufkens, Hubert G., v. Haelst, Ingrid M. M., Parel, Piet C. M., Scholten, Wim K., Sessink, F. G. M., Raschatt, R., Traversa, G., Donini, G., Arpino, C., Da Cas, R., Pasquin, P., Bernadotte af Wisborg G., Claesson C., Lundberg O., Thorslund M., Ferraro L., Marrazzo E., Ostino G., Tognoni G., Heerdink, Eibert R., Koppedraaijer, Corrie, Bakker, Albert, Bidoli E., Battistin M., Troncon M. G., Franceschi S., Serraino D., Marino, M., Matera, M. G., Berrino, L., Contaldi, C., Piucci, B., Rossi, F., Rolle C., Marrazzo E. 0., Murgia, V., Bussi, R., Schievano, P., Pedrini, A., Baraghini, M., Benini, A., Cataldo, M. M., Galletti, P., Magnani, M., Manzoli, M., Novi, M. V., Pezzi, O., Font M., Salmaso A. B., Mezzalira L., Braybrook, Saran, Walker, Roger, van Mil, J. W. F., Tromp, F. T. J., de Jong-v.d. Berg, L. T. W., Bakker, A., Paes, A. H. P., Soe-Agnie, C., Llopis, P., Tortajada, J. J., Font, I., Climente, M., Real, J. V., Almenar, D., Molins, C., Jiménez, N. V., Bellés Medall MD, Casterá Melchor DE, Marco Sena MA, Cantarinz Marti I., Abad Gimeno FJ, Török, J., Thurzó, L., Juárez J. C., Oliveras M., Hidalgo E., Cabañas M. J., Barroso C., Moraga F. A., Sánchez de Toledo J., Kollöffel, W. J., Driessen, F. G. W. H. M., Goldhoorn, P. B., Moral, M. A., Roglan, A., Mangues, M. A., Bonal, J., Clopés, A., Badell, I., Fraga, G., Deinum, J. T., van Lingen, R. A., Quak, J. M. E., Kuizenga, A. J., van Dam, J. G., Villani P., Maserati R., Viale P., Alberici F., Iacona I., Wasieczko, A., Szymura-Oleksiak, J., Wyska, E., Magulova, L., Sirotiakova, J., Letkovicova, M., Branger, E., Besse, D., Blin, O., Bille, F., Serratrice, G., Desnuelle, C., Grassin, J., Reben, I., Meunier, Ph., Antier, D., Berthet, M., Søndergaard B., Herborg H., Frøkjær B., Hepler C., Steckner, H., Bergold, A., Drings, P., Märkel, A., Manegold, C., Venning, Mary, Pazzagli, Luciana, Semmola, Maria Vittoria, Mannoni, Alessandro, Tersen I., Huchet J., Sevilla, E., Ferrari, J. M., Herreros de Tejada, A., Congedo, R., Font, M., Fraccaro, A., Osti, M., Pappagallo, G., Spolaor, A., Terrazzani, G., Vezzani, M., Edouard B., Laine G., Geeraerts D., Robays H., Carrera-Hueso, F. J., Font, B., Marquina, C., Idoate, A., Giráldez, J., Fernández, E., Lacasa, C., Guzzo, D., Martini, N., Boya, P. Giner, González, M. M. Negredo, Agulló, J. Muñoz, Mansilla, L. Lorente, Nahata, Milap C., Troncon, M. G., Cattaruzzi, C., Bilbao G., Galende I., Atañé C., Bermudez de Castro A., Delgado O., Escribano B., Frías J., Gabriel R., Gómez J. A., Gracia D., Gutiérrez E., Hellín T., Izquierdo J. L., Moreno A., Requena T., Sainz-Terreros M., Tejedor J. C., Torralba A., Vigil D., Scuffi, C., Trallori, G., Messori, A., Bardazzi, G., Bonanomi, A., Silvano, R., D'Albasio, G., Bardelli, F., Verona, Firenzee, Bardelli, F., Corrado, A., Ferriols R., Aleixander M. J., Garcia J., Faus M., Ibañez E., Alós M., Rinaldi, M., Pharmacy & Therapeutic Committee (Ps&TC), Collaborative Group, SIFO-Veneto Working Group on Clinical Trials, Working Group on the Elaboration of an Approval Conditions Document to certify the Clinical Trials Ethics Committees in the Autonomous Community of Madrid, and Area SIFO di Metanalisi

Published
1994
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14. Decorated pottery study: Analysis of pigments by x-ray absorbance spectroscopy measurements

Author

Barilaro, D., Crupi, V., Majolino, D., Venuti, V., Barone, G., D'Acapito, F., Bardelli, F., and Giannici, F.

Subjects
Pottery -- Spectra, Pottery -- Properties, Absorption spectra -- Analysis, Oxidation-reduction reaction -- Research, Physics
Abstract

The nondestructive x-ray absorbance spectroscopy (XAS) was used to carry out the characterization of pigments on decorated pottery fragments. The study observation showed Fe oxides as the main pigmenting agents in the most ancient fragment while other ceramic shards showed Fe oxides as well as Cu oxides.

Published
2007

24. Substitution site and effects on magnetism in Sr-for-Ca substituted CaBaCo4O7.

Author

Aurelio, G., Curiale, J., Bardelli, F., Junqueira Prado, R., Hennet, L., Cuello, G., Campo, J., and Thiaudière, D.

Subjects
MAGNETISM, STRONTIUM, CALCIUM compounds, X-ray diffraction, CRYSTAL structure, MAGNETIZATION
Abstract

Cationic substitutions in the novel magnetoelectric compound CaBaCo4O7 lead to profound changes in its magnetic and electric behaviors. In this work, we present a structural study of the isovalent substitution Sr-for-Ca in CaBaCo4O7. X-ray diffraction, as well as neutron powder diffraction experiments, are reported for a series of samples Ca1–xSrxBaCo4O7 with 0 ≤ x ≤ 0.10. Special emphasis is given to the identification of the substitution site, as Sr has also been reported to substitute for Ba in this crystal structure. The solubility limit for Sr at the Ca site is shown to be at x ≃ 0.08. The variation of lattice constants with Sr-doping firmly supports the Sr-for-Ca substitution. Rietveld refinements of the Sr-substituted samples are presented, and used as starting point to analyse the local structure around Sr by means of X-ray absorption spectroscopy at the Sr K-edge. Both the near-edge absorption and the extended absorption fine-structure confirm the substitution of Sr for Ca, giving definite support to the proposed nominal formula. In addition, macroscopic magnetization measurements are presented which reveal the striking effects of Sr-substitution over the magnetic landscape of this puzzling compound. [ABSTRACT FROM AUTHOR]

Published
2015
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25. Substitution site and effects on magnetism in Sr-for-Ca substituted CaBaCo4O7.

Author

Aurelio, G., Curiale, J., Bardelli, F., Junqueira Prado, R., Hennet, L., Cuello, G., Campo, J., and Thiaudière, D.

Subjects
MAGNETISM, STRONTIUM, CALCIUM compounds, CATIONS, MAGNETOELECTRIC effect, X-ray diffraction, EXPERIMENTS
Abstract

Cationic substitutions in the novel magnetoelectric compound CaBaCo4O7 lead to profound changes in its magnetic and electric behaviors. In this work, we present a structural study of the isovalent substitution Sr-for-Ca in CaBaCo4O7. X-ray diffraction, as well as neutron powder diffraction experiments, are reported for a series of samples Ca1-xSrxBaCo4O7 with 0 ≤ x ≤ 0:10. Special emphasis is given to the identification of the substitution site, as Sr has also been reported to substitute for Ba in this crystal structure. The solubility limit for Sr at the Ca site is shown to be at x ≃ 0:08. The variation of lattice constants with Sr-doping firmly supports the Sr-for-Ca substitution. Rietveld refinements of the Sr-substituted samples are presented, and used as starting point to analyse the local structure around Sr by means of X-ray absorption spectroscopy at the Sr K-edge. Both the near-edge absorption and the extended absorption fine-structure confirm the substitution of Sr for Ca, giving definite support to the proposed nominal formula. In addition, macroscopic magnetization measurements are presented which reveal the striking effects of Sr-substitution over the magnetic landscape of this puzzling compound. [ABSTRACT FROM AUTHOR]

Published
2015
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27. New insights on the biomineralization process developing in human lungs around inhaled asbestos fibres

Author

Bardelli F.[1], Veronesi G.[2, Capella S.[4, Bellis D.[5], Charlet L.[6], Cedola A.[1], Beluso E.[4, and 7

Subjects
iron storage, ferruginous bodies, speciation, adsorption, malignant mesothelioma, in-vitro, body, biological samples, ferrihydrite, X-ray absorption
Abstract

Once penetrated into the lungs of exposed people, asbestos induces an in vivo biomineralisation process that leads to the formation of a ferruginous coating embedding the fibres. The ensemble of the fibre and the coating is referred to as asbestos body and is believed to be responsible for the high toxicological outcome of asbestos. Lung tissue of two individuals subjected to prolonged occupational exposure to crocidolite asbestos was investigated using synchrotron radiation micro-probe tools. The distribution of K and of elements heavier than Fe (Zn, Cu, As, and Ba) in the asbestos bodies was observed for the first time. Elemental quantification, also reported for the first time, confirmed that the coating is highly enriched in Fe (~20% w/w), and x-ray absorption spectroscopy indicated that Fe is in the 3+ oxidation state and that it is present in the form of ferritin or hemosiderin. Comparison of the results obtained studying the asbestos bodies upon removing the biological tissue by chemical digestion and those embedded in histological sections, allowed unambiguously distinguishing the composition of the asbestos bodies, and understanding to what extent the digestion procedure altered their chemical composition. A speculative model is proposed to explain the observed distribution of Fe.

Published
2017

33. Local structure in LaMnO3 and CaMnO3 perovskites: A quantitative structural refinement of Mn K -edge XANES data

Author

MONESI, C., MENEGHINI, C., BARDELLI, F., BENFATTO, M., MANJU, U., SARMA, MOBILIO S., MOBILIO, Settimio, Monesi, C., Meneghini, C., Bardelli, F., Benfatto, M., Mobilio, Settimio, Manju, U., Sarma, and Mobilio, S.

Abstract

Hole-doped perovskites such as La1-xCaxMnO3 present special magnetic and magnetotransport properties, and it is commonly accepted that the local atomic structure around Mn ions plays a crucial role in determining these peculiar features. Therefore experimental techniques directly probing the local atomic structure, like x-ray absorption spectroscopy (XAS), have been widely exploited to deeply understand the physics of these compounds. Quantitative XAS analysis usually concerns the extended region [extended x-ray absorption fine structure (EXAFS)] of the absorption spectra. The near-edge region [x-ray absorption near-edge spectroscopy (XANES)] of XAS spectra can provide detailed complementary information on the electronic structure and local atomic topology around the absorber. However, the complexity of the XANES analysis usually prevents a quantitative understanding of the data. This work exploits the recently developed MXAN code to achieve a quantitative structural refinement of the Mn K-edge XANES of LaMnO3 and CaMnO3 compounds; they are the end compounds of the doped manganite series LaxCa1-xMnO3. The results derived from the EXAFS and XANES analyses are in good agreement, demonstrating that a quantitative picture of the local structure can be obtained from XANES in these crystalline compounds. Moreover, the quantitative XANES analysis provides topological information not directly achievable from EXAFS data analysis. This work demonstrates that combining the analysis of extended and near-edge regions of Mn K-edge XAS spectra could provide a complete and accurate description of Mn local atomic environment in these compounds.

Published
2005

34. Arsenic-bearing calcite in natural travertines: evidence from sequential extraction, μXAS, and μXRF

Author

Costagliola P. [1], Bardelli F. [2], Benvenuti M. [1], Di Benedetto F. [1, Lattanzi P. [4], Romanelli M. [1, Paolieri M. [1], Rimondi V. [1], and Vaggelli G. [5]

Subjects
Calcite, Diffusion, microXAS, Extraction (chemistry), Ambientale, Mineralogy, chemistry.chemical_element, General Chemistry, PE10_10, micro-XAS, PE10_11, Natural (archaeology), micro-XRF, Bioavailability, Arsenic, Calcium Carbonate, chemistry.chemical_compound, sequential extractions, chemistry, Oxidation state, microXRF, Environmental Chemistry, calcite, Geology
Abstract

Recent studies demonstrated that synthetic calcite may host considerable amounts of arsenic (As). In this paper, the concentration of As in natural calcite was determined using two novel, specifically designed, sequential extraction procedures. In addition, the oxidation state of As and its distribution between calcite and coexisting Fe-oxyhydroxides was unravelled by ?XRF elemental mapping and As K-edge ?XAS spectroscopy. Our results conclusively demonstrate that arsenic can be found in natural calcite up to 2 orders of magnitude over the normal crustal As abundances. Because of the large diffusion of calcite in the environment, this phase may exert an important control on As geochemistry, mobility, and bioavailability.

Published
2013
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35. Journal of Physics: Condensed Matter

Author

Malta, M., Saleta, M. E., Aurelio, G., Bardelli, F., Sánchez, R. D., and Torresi, R. M.

Abstract

Texto completo: acesso restrito. p. 1-8 Submitted by Edileide Reis (leyde-landy@hotmail.com) on 2014-05-15T15:16:02Z No. of bitstreams: 1 M. Malta.pdf: 1565956 bytes, checksum: 491091df0ac866dc4795af9d2010994e (MD5) Made available in DSpace on 2014-05-15T15:16:02Z (GMT). No. of bitstreams: 1 M. Malta.pdf: 1565956 bytes, checksum: 491091df0ac866dc4795af9d2010994e (MD5) Previous issue date: 2012 Vanadium oxide nanotubes constitute promising materials for applications in nanoelectronics as cathode materials, in sensor technology and in catalysis. In this work we present a study on hybrid vanadium oxide/hexadecylamine multiwall nanotubes doped with Co ions using state of the art x-ray diffraction and absorption techniques, to address the issue of the dopant location within the nanotubes' structure. The x-ray absorption near-edge structure analysis shows that the Co ions in the nanotubes are in the 2 + oxidation state, while extended x-ray absorption fine structure spectroscopy reveals the local environment of the Co2+ ions. Results indicate that Co atoms are exchanged at the interface between the vanadium oxide's layers and the hexadecylamines, reducing the amount of amine chains and therefore the interlayer distance, but preserving the tubular shape. The findings in this work are important for describing Co2+ interaction with vanadium oxide nanotubes at the molecular level and will help to improve the understanding of their physicochemical behavior, which is desired in view of their promising applications.

Published
2012
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43. Spectroscopic investigations of uranyl reduction by Fe-bearing clays

Author

Chakraborty, S., Boivin, Ff, Gehin, A., Banerjee, D., Andreas Scheinost, Greneche, Jm, Mullet, M., Bardelli, F., Charlet, L., Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Laboratoire Central des Ponts et Chaussées (LCPC)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Resource Ecology [Dresden], Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Laboratoire de physique de l'état condensé (LPEC), Centre National de la Recherche Scientifique (CNRS)-Le Mans Université (UM), Laboratoire de Chimie Physique et Microbiologie pour l'Environnement (LCPME), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), European Synchrotron Radiation Facility (ESRF), This work is financially supported by ACTINET (07-21), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), Institute of Resource Ecology, Institute of Radiochemistry, Le Mans Université (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)

Subjects
EXAFS, XPS, Uranium, reduction, clays
Abstract

Ferrous iron in clay is a potential natural reductant in anoxic environments. The reduction of UVI by FeII could be an important pathway for the immobilization of uranium in natural subsurface environments as well as in high-level nuclear waste (HLW) repositories. In the present study, we employed three dithionite-bicarbonate-citrate (DCB) treated, Ca-exchanged, Fe-bearing clays viz. montmorillonite (FeSM), Fe-rich smectite (Swa-1) and nontronite (NAu-2) with varying Fe content, and studied the reactivity of structural and readsorbed (surface complexed) Fe(II) species with respect to U sorption and/or reduction at pH 6 in a CO2-free anoxic atmosphere (

Published
2009
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49. Spectroscopic studies of arsenic retention onto biotite

Author

Chakraborty, S., Bardelli, F., Mullet, M., Greneche, J.-M., Varma, S., Ehrhardt, J.-J., Banerjee, D., Charlet, L., Chakraborty, S., Bardelli, F., Mullet, M., Greneche, J.-M., Varma, S., Ehrhardt, J.-J., Banerjee, D., and Charlet, L.

Abstract

Biotite is a constituent Fe-bearing mineral of Delta subsoils in India and Bangladesh and has been hypothesized as a primary source of arsenic (As). The adsorption behavior of As onto structural Fe(II,III)-bearing biotite fractions (<50 µm) was investigated in the pH range 4-8 under a CO2-free, anoxic condition (O2 <1 ppmv) using X-ray Photoelectron Spectroscopy (XPS) and X-ray Absorption Spectroscopy (XAS). The batch experiments indicate that As adsorption is strongly pH dependent and As(V) adsorbs more efficiently than As(III). X-ray Absorption Near-Edge Structure (XANES) spectra show no oxidation or reduction of As by biotite after 3 days reaction with As(III) or As(V) solutions. Extended X-ray Absorption Fine Structure (EXAFS) spectroscopic results suggest that As(III) forms bidentate mononuclear edge-sharing (2E) and bidentate binuclear corner-sharing (2C) surface complexes at pH 7.7 as indicated by the average As-Fe bond distances at 3.00 ± 0.02 Å and 3.37 ± 0.03 Å respectively. The surface speciation retrieved by XPS does not provide any evidence of reduction of As(V) on biotite after 30 days further confirming the thermodynamic prediction and the XANES results. This study has therefore significant environmental implications for As contaminated areas, where biotite retards the release of As into reducing groundwater. The changes in soil redox condition and weathering of biotite may likely contribute to the occurrence of high As in groundwater.

Published
2011

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