Giovanni B Andreozzi

Publications (13) View all

• Article: Short-range order of Fe2+ in sphalerite by 57Fe Mössbauer spectroscopy and magnetic susceptibility

  F. Di Benedetto, G. B. Andreozzi, G. P. Bernardini, M. Borgheresi, A. Caneschi, C. Cipriani, D. Gatteschi, M. Romanelli
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  ABSTRACT: An extensive study of natural and synthetic Fe-bearing sphalerites (Fe-content ranging from 0.005afu to 0.250afu) has been carried out through the combined investigations of the temperature dependence of the magnetic susceptibility and of the 57Fe Mössbauer spectroscopic features. Magnetic susceptibility measurements evidence, in the low temperature regime, the presence of clustered Fe even in the most diluted samples, whereas all the Mössbauer spectra are described in terms of variable proportions of three components, namely one single and two doublets absorption, centred at the same isomer shift, relative to Fe ions and to different Fe clusters, respectively. The comparison of all the experimental results points out a self-affinity of Fe ions in sphalerite favoured by the superexchange interaction, which stabilises the formation of clusters even in diluted samples and may be related to both macroscopic inhomogeneous distribution and crystal zoning.
  Physics and Chemistry of Minerals 04/2012; 32(5):339-348. · 1.73 Impact Factor
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  Available from: Lorenzo Stievano

  Article: Iron topochemistry and surface reactivity of amphibole asbestos: relations with in vitro toxicity.

  Alessandro Pacella, Giovanni B Andreozzi, Jeanine Fournier, Lorenzo Stievano, Federica Giantomassi, Guendalina Lucarini, Maria Rita Rippo, Armanda Pugnaloni
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  ABSTRACT: Chemical reactivity of asbestos tremolite from Italy and USA localities and Union Internationale Contre le Cancer (UICC) crocidolite was studied in relation to Fe content, oxidation state, and structural coordination. Direct correlation between amount of Fe(2+) at the exposed M(1) and M(2) sites of the amphibole structure and fiber chemical reactivity was established. The in vitro toxicity of the same samples was investigated on human alveolar A549 cell line. Relationship between crystal-chemical features and cell toxicity is not straightforward. UICC crocidolite has Fe content and chemical reactivity largely higher than that of tremolite samples, but all show comparable in vitro toxic potential. Results obtained evidenced that Fe topochemistry is not a primary factor for induced cell toxicity, though it accounts for asbestos chemical reactivity (and possibly genotoxicity).
  Analytical and Bioanalytical Chemistry 11/2011; 402(2):871-81. · 3.78 Impact Factor
• Article: Combined use of X-ray photoelectron and Mössbauer spectroscopic techniques in the analytical characterization of iron oxidation state in amphibole asbestos.

  Marzia Fantauzzi, Alessandro Pacella, Davide Atzei, Antonio Gianfagna, Giovanni B Andreozzi, Antonella Rossi
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  ABSTRACT: Asbestos fibers are an important cause of serious health problems and respiratory diseases. The presence, structural coordination, and oxidation state of iron at the fiber surface are potentially important for the biological effects of asbestos because iron can catalyze the Haber-Weiss reaction, generating the reactive oxygen species *OH. Literature results indicate that the surface concentration of Fe(III) may play an important role in fiber-related radical formation. Amphibole asbestos were analyzed by X-ray photoelectron spectroscopy (XPS) and Mössbauer spectroscopy, with the aim of determining the surface vs. bulk Fe(III)/Fe(tot) ratios. A standard reference asbestos (Union Internationale Contre le Cancer crocidolite from South Africa) and three fibrous tremolite samples (from Italy and USA) were investigated. In addition to the Mössbauer spectroscopy study of bulk Fe(III)/Fe(tot) ratios, much work was dedicated to the interpretation of the XPS Fe2p signal and to the quantification of surface Fe(III)/Fe(tot) ratios. Results confirmed the importance of surface properties because this showed that fiber surfaces are always more oxidized than the bulk and that Fe(III) is present as oxide and oxyhydroxide species. Notably, the highest difference of surface/bulk Fe oxidation was found for San Mango tremolite--the sample that in preliminary cytotoxicity tests (MTT assay) had revealed a cell mortality delayed with respect to the other samples.
  Analytical and Bioanalytical Chemistry 03/2010; 396(8):2889-98. · 3.78 Impact Factor
• Article: Structural and spectroscopic characterization of a suite of fibrous amphiboles with high environmental and health relevance from Biancavilla (Sicily, Italy)

  Giovanni B Andreozzi, Paolo Ballirano, Antonio Gianfagna, Simona Mazziotti-Tagliani, Alessandro Pacella
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  ABSTRACT: This study reports new spectroscopic and structural data of fibrous amphiboles from the volcanic area of Biancavilla (Sicily, Italy) that generated interest because of an anomalous increase of pleural mesothelioma of inhabitants. Each of the four samples is made of loose fibers, which show an edenite-winchite (fluorine) compositional trend, with significant tremolite component. Small amounts of iron (3.6-6.0 wt% FeO(tot)) were identified in all samples, and the Fe(3+)/Fe(tot) ratios were evaluated by Mossbauer spectroscopy: two samples are characterized by Fe(3+)/Fe(tot) ratios between 50 and 70%, and the other two have Fe(3+)/Fe(tot) ratios higher than 90%. The OH-stretching region was investigated by FTIR, and no absorption bands were observed. Structural investigation was carried out by X-ray powder diffraction using the Rietveld method. Cell parameters, positional parameters for all the atoms, and site scattering for M1, M2, M3, M4, A, and A(m) were refined. The most important differences with respect to prismatic fluoro-edenite are the decrease of beta, a, and c with decreasing Ca content, A-site occupancy, and tetrahedral Al content, respectively. By combining chemical, spectroscopic, and structural data, possible site occupancies were obtained. In particular, it was found that Fe(2+) is distributed between M1 and M2 sites; moreover, for the two samples enriched in Fe(2+), it is also present at M4. Fe(3+) is generally ordered at M2 site; however, for the two samples enriched in Fe(3+), minor amounts are partially disordered between M1 and M3 sites. For the Biancavilla amphibole fibers, the large compositional variation observed in every sample makes the classification very difficult, so that the regulatory agencies would not classify as "asbestos" the whole mineral series, because of the large components of edenite and winchite in addition to tremolite. Many common features were found with respect to amphibole fibers from Libby, Montana, including Fe contents and oxidation state. Preliminary results of in vitro toxicological tests on Biancavilla fibers confirmed their high reactivity, and suggest that the samples with the highest Fe(2+) contents induce a rapid start to cell mortality.
  American Mineralogist 10/2009; 94(10):1333-1340. · 2.17 Impact Factor
• Article: Crystal structure and iron topochemistry of erionite-K from Rome, Oregon, USA

  Paolo Ballirano, Giovanni B Andreozzi, Meral Dogan, Umran A Dogan
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  ABSTRACT: A complete crystal-chemical characterization of erionite-K from Rome, Oregon, was obtained by combining field emission scanning electron microscopy, laboratory parallel-beam transmission powder diffraction, and (57)Fe Mossbauer spectroscopy. Rietveld refinement results evidenced that the most striking difference in comparison with the structure of erionite-Ca is significant K at a K2 site ((1)/(2), 0, 0), which is empty in erionite-Ca. In addition, site Ca1 shows low occupancy and Ca3 is vacant. The oxidation and coordination state of Fe, whose occurrence was revealed by chemical analysis, have been clarified by exploiting room- and low-temperature (57)Fe Mossbauer spectroscopy. The majority of Fe (95%) was attributed to Fe(3+)-bearing, superparamagnetic, oxide-like nanoparticles with dimensions between 1 and 9 nm, and the remaining 5% was attributed to hematite particles with size >= 10 nm, both located on the crystal surface.
  American Mineralogist 01/2009; 94(8-9):1262-1270. · 2.17 Impact Factor