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Pagina personale di Daniele MALFERRARI

Dipartimento di Scienze Chimiche e Geologiche
Dipartimento di Scienze Chimiche e Geologiche - Sede Dipartimento di Scienze Chimiche e Geologiche

Bernini, Fabrizio; Castellini, Elena; Malferrari, Daniele; Castro, German Rafael; Sainz Díaz, Claro Ignacio; Brigatti, Maria Franca; Borsari, Marco ( 2017 ) - Effective and Selective Trapping of Volatile Organic Sulfur Derivatives by Montmorillonite Intercalated with a μ-oxo Fe(III)-Phenanthroline Complex - ACS APPLIED MATERIALS & INTERFACES - n. volume 9 - pp. da 1045 a 1056 ISSN: 1944-8244 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The mu-oxo Fe(III) phenatithroline Complex [(OH2)(3)(Phen)FeOFe(Phen) (OH2)(3)](+4) intercalated in montmorillonite provides a stable hybrid material. In this study, the ability and efficiency of this material to immobilize thiols in gas phase, acting as a trap at the solid-gas interface, were investigated. Aliphatic thiols containing both hydrophilic and hydrophobic end groups were chosen to test the selectivity of this gas trap. DR-UV vis, IR, elemental analysis, thermal analysis and evolved gas mass spectrometry, X-ray powder diffraction, and X-ray absorption spectroscopy techniques were employed to characterize the hybrid material before and after thiol exposure and to provide information on the entrapping process. Thiol immobilization is very large, up to 21% w/w for heptanethiol. In addition, evidence was obtained that immobilization occurs through the formation of a covalent bond between the iron of the complex and the sulfur of the thiol. This provides an immobilization process characterized by a higher stability with respect to the method's based on physi-adsorption. Thiol immobilization resulted thermally reversible at least for 20 adsorption/desorption cycles. Unlike standard desulfurization processes like hydrotreating and catalytic oxidation which work at high temperatures and pressures, the present system is able to efficiently trap thiols at room temperature and pressure, thus saving energy. Furthermore,we found that the selectivity of thiol immobilization can be tuned acting on the amount of complex intercalated in montmorillonite. In particular, montmorillonite semisaturated with the complex captures both hydrophobic and hydrophilic thiols, while the saturated montmorillonite shows a strong selectivity toward the hydrophobic molecules.

Castellini, Elena; Malferrari, Daniele; Bernini, Fabrizio; Brigatti, Maria Franca; Castro, German Rafael; Medici, Luca; Mucci, Adele; Borsari, Marco ( 2017 ) - Baseline studies of The Clay Minerals Society Source Clay montmorillonite STx-1b - CLAYS AND CLAY MINERALS - pp. da 220 a 233 ISSN: 0009-8604 [Articolo in rivista (262) - Articolo su rivista]
Abstract

For more than forty years, The Clay Minerals Society has dispensed a set of source clays which have enabled a large number of researchers to work on identical materials. Many of these source clays remained unchanged over the years but, conversely, other clays have gone out of stock and thus were replaced. This was the fate of montmorillonite STx-1a, which was replaced by STx-1b. Although STx-1a and STx-1b share many basic chemical and mineralogical features, some minor differences exist that can affect behavior. A baseline characterization of the source clay STx-1b, which was the objective of this study, was, therefore, necessary to provide researchers a tool useful not only for new investigation but also to compare new results obtained on STx-1b with literature data on STx-1a. This characterization was gained using traditional and advanced methods that include: 1) chemical composition (major and trace elements); 2) cation exchange capacity determination; 3) thermal analyses coupled with evolved gas mass spectrometry; 4) quantitative mineralogical characterization using powder X-ray diffraction and Rietveld-RIR (Reference Intensity Ratio) refinement; 5) X-ray absorption spectroscopy at the Fe K-edge; 6) diffuse reflectance ultraviolet-visible and infrared spectroscopies; 7) 29Si, 27Al, and 1H magic-angle spinning nuclear magnetic resonance measurements. According to this multi-analytical approach, the montmorillonite chemical formula is [4](Si7.753 Al0.247) [6](Al3.281 Mg0.558 Fe0.136 Ti0.024 Mn0.002) [12](Ca0.341 Na0.039 K0.061) O20 (OH)4.

Ferretti, Annalisa; Malferrari, Daniele; Medici, Luca; Savioli, Martina ( 2017 ) - Diagenesis does not invent anything new: Precise replication of conodont structures by secondary apatite - SCIENTIFIC REPORTS - n. volume 7 - pp. da 1624 a 1632 ISSN: 2045-2322 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Conodont elements are important archives of sea/pore water chemistry yet they often exhibit evidence of diagenetic mineral overgrowth which may be biasing measurents. We decided to investigate this phenomenon by characterising chemically and crystallographically, the original biomineral tissue and the diagenetic mineral nature of conodont elements from the Ordovician of Normandy. Diagenetic apatite crystals observed on the surface of conodont elements show distinctive large columnar, blocky or web-like microtextures. We demonstrate that these apatite neo-crystals exhibit the same chemical composition as the original fossil structure. X-ray microdiffraction has been applied herein for the first time to conodont structural investigation. Analyses of the entire conodont element surface of a variety of species have revealed the existence of a clear pattern of crystal preferred orientation. No significant difference in unit cell parameters was documented between the newly formed apatite crystals and those of the smooth conodont surfaces, thus it emerges from our research that diagenesis has strictly replicated the unit cell signature of the older crystals.

Brigatti, Maria Franca; Díaz, Claro Ignacio Sainz; Borsari, Marco; Bernini, Fabrizio; Castellini, Elena; Malferrari, Daniele ( 2017 ) - Crystal chemical characterization and computational modeling of a μ-oxo Fe(III) complex with 1,10-phenanthroline clarify its interaction and reactivity with montmorillonite - RENDICONTI LINCEI. SCIENZE FISICHE E NATURALI - n. volume 28 - pp. da 605 a 614 ISSN: 2037-4631 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work provides a systematic study of the μ-oxo-di-fac-[triaqua-(1,10-phenanthroline-κ2N,N′)-iron(III)]bis(sulfate), [(OH2)3(phen)FeOFe(phen)(OH2)3] (SO4)2 (phen = phenanthroline). Crystal structure is determined by single-crystal X-ray diffraction data and refined to R = 0.039. The crystal structure is monoclinic (Z = 2), space group P21 with unit cell dimensions a = 8.5157(3), b = 17.6434(5), c = 9.9678(3) Å, β = 90.133(2)°, V = 1497.62(8) Å3. The triaqua(1,10-phenanthroline)iron(III) parts are linked through one oxo-bridge. Both Fe(III) cations show a distorted octahedral coordination. The single-crystal data are complemented by computational chemistry modeling at quantum mechanical level, X-ray powder diffraction at room and high temperature conditions and by thermal analysis. Molecular modeling suggests that the role of the crystallization water molecules is critical to establish the intermolecular interactions for the stability of the crystal structure.

Ferretti, Annalisa; Malferrari, Daniele; Medici, Luca; Savioli, Martina ( 2016 ) - Overgrowth of apatite crystals on the surface of Late Ordovician conodonts from Normandy, northern France ( La Società Paleontologica Italiana a Faenza: XVI Riunione annuale SPI, Faenza. - - 25-27 May 2016) ( - PALEODAYS 2016. La Società Paleontologica Italiana a Faenza: XVI Riunione annuale SPI, Faenza. ) - pp. da 46 a 47 ISBN: 9791220009836 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Peculiar apatite overgrowth on Ordovician conodont elements are described.

Ferretti, Annalisa; Malferrari, Daniele; Medici, Luca; Savioli, Martina ( 2016 ) - Crystals on the rocks. Apatite overgrowth on conodont elements from the Late Ordovician of Normandy, France ( IGCP 591: The Early to Middle Paleozoic Revolution. Closing Meeting - - 6-9 July 2016) ( - IGCP 591: The Early to Middle Paleozoic Revolution ) - pp. da 103 a 103 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Apatite overgrowth patterns on Ordovician conodonts are here referred to metamorphism.

Muniz-Miranda, Francesco; Lodesani, Federica; Tavanti, Francesco; Presti, Davide; Malferrari, Daniele; Pedone, Alfonso ( 2016 ) - Supercritical CO2 Confined in Palygorskite and Sepiolite Minerals: A Classical Molecular Dynamics Investigation - JOURNAL OF PHYSICAL CHEMISTRY. C - n. volume 120 - pp. da 26945 a 26954 ISSN: 1932-7447 [Articolo in rivista (262) - Articolo su rivista]
Abstract

We have investigated the ability of two modular phyllosilicates (palygorskite and sepiolite) to store CO2 molecules inside their structural channels by means of classical molecular dynamics. Several models containing an increasing supercritical-CO2/H2O ratio into the phyllosilicate channels have been built and the structural and dynamic properties of carbon dioxide and water molecules investigated in detail. We found that both clay minerals can achieve this goal, with sepiolite being able to store more carbon dioxide molecules (and more stably) than palygorskite, due to the larger channels of the former. Interestingly, with the increase of CO2 molecules inside the minerals, the diffusivity of both water and carbon dioxide drastically decreases and carbon dioxide molecules tend to arrange themselves in an ordered pattern. (Figure Presented).

Ventruti, Gennaro; Ventura, Giancarlo Della; Corriero, Nicola; Malferrari, Daniele; Gualtieri, Alessandro F.; Susta, Umberto; Lacalamita, Maria; Schingaro, Emanuela ( 2016 ) - In situ high-temperature X-ray diffraction and spectroscopic study of fibroferrite, FeOH(SO4)·5H2O - PHYSICS AND CHEMISTRY OF MINERALS - n. volume 43(8) - pp. da 587 a 595 ISSN: 0342-1791 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The thermal dehydration process of fibroferrite, FeOH(SO4)·5H2O, a secondary iron-bearing hydrous sulfate, was investigated by in situ high-temperature synchrotron X-ray powder diffraction (HT-XRPD), in situ high-temperature Fourier transform infrared spectroscopy (HT-FTIR) and thermal analysis (TGA-DTA) combined with evolved gas mass spectrometry. The data analysis allowed the determination of the stability fields and the reaction paths for this mineral as well as characterization of its high-temperature products. Five main endothermic peaks are observed in the DTA curve collected from room T up to 800 °C. Mass spectrometry of gases evolved during thermogravimetric analysis confirms that the first four mass loss steps are due to water emission, while the fifth is due to a dehydroxylation process; the final step is due to the decomposition of the remaining sulfate ion. The temperature behavior of the different phases occurring during the heating process was analyzed, and the induced structural changes are discussed. In particular, the crystal structure of a new phase, FeOH(SO4)·4H2O, appearing at about 80 °C due to release of one interstitial H2O molecule, was solved by ab initio real-space and reciprocal-space methods. This study contributes to further understanding of the dehydration mechanism and thermal stability of secondary sulfate minerals.

Bernini, Fabrizio; Malferrari, Daniele; Pignataro, Marcello; Bortolotti, Carlo Augusto; Di Rocco, Giulia; Lancellotti, Lidia; Brigatti, Maria Franca; Kayed, Rakez; Borsari, Marco; Del Monte, Federica; Castellini, Elena ( 2016 ) - Pre-amyloid oligomers budding:a metastatic mechanism of proteotoxicity - SCIENTIFIC REPORTS - n. volume 6 - pp. da 35865 a 35875 ISSN: 2045-2322 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The pathological hallmark of misfolded protein diseases and aging is the accumulation of proteotoxic aggregates. However, the mechanisms of proteotoxicity and the dynamic changes in fiber formation and dissemination remain unclear, preventing a cure. Here we adopted a reductionist approach and used atomic force microscopy to define the temporal and spatial changes of amyloid aggregates, their modes of dissemination and the biochemical changes that may influence their growth. We show that pre-amyloid oligomers (PAO) mature to form linear and circular protofibrils, and amyloid fibers, and those can break reforming PAO that can migrate invading neighbor structures. Simulating the effect of immunotherapy modifies the dynamics of PAO formation. Anti-fibers as well as anti-PAO antibodies fragment the amyloid fibers, however the fragmentation using anti-fibers antibodies favored the migration of PAO. In conclusion, we provide evidence for the mechanisms of misfolded protein maturation and propagation and the effects of interventions on the resolution and dissemination of amyloid pathology.

Brigatti, Maria Franca; Elmi, Chiara; Guggenheim, Stephen; Malferrari, Daniele; Poppi, Marco; ( 2016 ) - An alternative method of calculating cleavage energy: The effect of compositional domains in micas - AMERICAN MINERALOGIST - n. volume 101 - pp. da 2738 a 2746 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

Cell parameters and atomic coordinates for the true micas are varied to simulate layer deformation along the [001]* direction by an external force. The resulting (deformed) structures are then used to determine bonding forces and to calculate a maximum force component along the [001]*. Bonding forces are compared to experimental observations of bond lengths of the interlayer, octahedral, and tetrahedral sites. Calculated bonding forces are consistent with experimental observations that locate the cleavage plane along the interlayer. Because many studies have shown that the chemical composition of the cleavage surface often differs from the structure of the bulk, compositional variations were considered in determining cleavage energy. The chemical composition of the cleavage surface may produce a reduction in cleavage energy. This reduction in energy depends on various elements occurring in greater number at the cleavage surface than in the bulk. A reduction in cleavage energy occurs if there is a reduction in the interlayer site size, as measured by the area defined by the first-coordination basal oxygen atoms. In addition, a reduction in lateral cell dimensions and an increase in the bonding force between the basal oxygen atoms and the interlayer cation also results in a reduction in cleavage energy in the direction normal to the layer. Joins considered are phlogopite–annite, tetra-ferriphlogopite–tetra-ferri-annite, polylithionite– siderophyllite, muscovite–celadonite, and muscovite–paragonite. A lack of homogeneity in composition may produce preferential cleavage locations within the family of (001) planes. The cleavage energy appears to be greater for homogeneous synthetic micas compared to natural micas.

Ferretti, Annalisa; Cavalazzi, Barbara; McLaughlin, Patrick I.; Barbieri, Roberto; Emsbo, Poul; Foucher, Frédéric; Malferrari, Daniele; Messori, Fabio; Westall, Frances ( 2015 ) - Can facies act as a chronostratigraphical tool? ( 2nd International Congress of Stratigraphy STRATI 2015 - - 19- 23 July 2015) ( - Abstracts ) - BERICHTE DES INSTITUTES FÜR GEOLOGIE UND PALÄONTOLOGIE DER KARL-FRANZENS-UNIVERSITÄT GRAZ, ÖSTERREICH - n. volume 21 - pp. da 108 a 108 ISSN: 1608-8166 [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Results demonstrate that the Appalachian ironstones seem to reflect the same microbially-mediated iron mineralization already documented in the Carnic Alps.

Malferrari, Daniele; Laurora, Angela ( 2015 ) - I minerali e i metodi sperimentali per la determinazione delle nuove specie mineralogiche ( - Minerali della provincia di Reggio Emilia ) (AMI - Ass. Micromineralogica Italiana ITA ) - pp. da 11 a 33 ISBN: 9788890554124 ISSN: - [Contributo in volume (Capitolo o Saggio) (268) - Capitolo/Saggio]
Abstract

La parola minerale è utilizzata in diversi modi, spesso impropriamente; per esempio in economia per minerale si intende qualsiasi materiale estratto dalla Terra (incluso carbone, petrolio, sabbia, ghiaia ecc.), mentre in mineralogia la definizione è molto più restrittiva. Si definisce infatti minerale un corpo naturale, per lo più solido e inorganico, omogeneo dal punto di vista chimico, in quella condizione stabile e anisotropa dello stato solido che è lo stato cristallino. Il minerale è una sostanza che si forma naturalmente durante processi geologici che hanno luogo sulla Terra o su corpi extraterrestri e che conferiscono alla sostanza stessa ben definite proprietà. La caratterizzazione di queste proprietà diviene, quindi, un mezzo univoco per stabilire se una sostanza di cui siamo venuti in possesso è o non è un minerale e se è una specie mineralogica già nota o nuova. Il presente lavoro, dopo una doverosa premessa sulla definizione di minerale e sulle restrizioni a essa applicate, si articola in una sintesi delle principali e più recenti procedure analitiche necessarie per determinare sia quelle proprietà fisiche e ottiche, sia quei parametri chimici cristallografici che servono per definire univocamente una nuova specie minerale.

Angela, Laurora; Daniele, Malferrari; Passaglia, Elio ( 2013 ) - Impianto per trattare sostanze organiche e produrre un materiale fertilizzante [Brevetto (285) - Brevetto]
Abstract

L’invenzione concerne un impianto per trattare sostanze organiche derivanti da rifiuti, scarti e/o decomposizioni – in particolare sostanze organiche contenenti azoto ammoniacale o ammonio, quali reflui zootecnici in forma liquida e/o digestati derivanti da processi di degradazione organica con microorganismi – così da produrre un materiale fertilizzante.

D. Malferrari; A. Laurora; C. Elmi; M. F. Brigatti; L. Medici; M. C. Zeqireja ( 2012 ) - Channel Sediment Characterization and Evaluation of the Potential Impact of Iron-Rich Phases on the Use of Sediments in Brick Production - ENVIRONMENTAL ENGINEERING SCIENCE - n. volume 29(9) - pp. da 840 a 847 ISSN: 1092-8758 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Using data collected at both room temperature and higher temperatures, this study examined the mineralogy of, and iron coordination shell in, polluted sediments from drainage and irrigation channels. As a part of the study, mineralogical characteristics of iron phases of canal sediments were examined to determine if these sediments could be used in place of common clays for the production of bricks. While such use would reduce the impact of these wastes on the environment, an excess of iron in these sediments could affect some important features of bricks. Therefore, this study examined the oxidation state of iron as well as its structural location in the mineral matrix. X-ray powder diffraction, thermal analysis, and X-ray absorption spectroscopy were used to examine sediments and bricks manufactured from irrigation and drainage channels of the Po River region in northeast Italy. Results indicated that canal sediments can be used as row materials in clay brick production. In fact, the process temperature (950°C) that characterized brick production was similar to the temperature used for thermal treatment of polluted sediments in this study.

C. Elmi; M.F. Brigatti; L. Pasquali; M. Montecchi; S. Nannarone; D. Malferrari ( 2011 ) - Crystal chemistry and surface features of a 2M1 paragonitic muscovite ( Geoitalia 2011 - - 19-23 settembre 2001) ( - Epitome ) - EPITOME - n. volume 4 - pp. da 218 a 219 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

The paragonitic muscovite considered [XII](K1.722 Na0.251 Ba0.010) [VI](Fe2+0.140 Al3+3.769 Cr3+0.003 Mg0.074 Ti0.012 Mn0.002) [IV](Al1.897 Si6.103) O20 (F0.109 OH3.891) came from Antarctica, it is monoclinic, 2M1 polytype, with symmetry C2/c and unit cell parameters a = 5.1969(1), b = 9.0138(3), c = 20.0835(7) (Å) and β = 95.763(2) (°).By using a multi-analytical approach this study describes the crystal chemical features of muscovite determined both in the bulk and on the uppermost surface layers. The bulk structure was refined by single crystal X-ray diffraction and the final refinement yielded the following agreement factor R = 0.0299. The two tetrahedral sites, T1 and T2, present similar distances (<T1-O> = 1.643 Å and <T2-O> = 1.647 Å) and distortion parameter values, thus evidencing a disordered distribution of [IV]Si and [IV]Al in tetrahedral sites. Tetrahedral ring is significantly distorted (α = 11.2°) and the tetrahedral basal oxygen atoms plane is remarkably wavy (Δz = 0.224Å). tetrahedral ring distortion affects not only the topology of the cleavage plane, but also the coordination of the interlayer cation, which reduces from twelve to eight. Crystal chemical modifications at mineral surface were investigated via X-ray Photoelectron Spectroscopy (XPS), by comparing data related to surface to the ones characterizing the bulk. A peculiarity of muscovite from Antarctica is a limited Na for K interlayer substitution, which was found in the bulk as well as on the mineral surface. It is well known that in micas the coordination of the interlayer cation can vary from twelve to six, depending on the distortion of the hexagonal tetrahedral ring, as measured by  angle, as observed and predicted by Weiss et al. [1].The interlayer cation K (binding energy = 293.36 eV) is confirmed to be eight-fold coordinated [2]. Na (binding energy = 1071.02 eV) substitutes K both in the bulk and at the surface. Na coordination, at mineral surface, reduces from eight to six [3]. The six-fold coordination presented by Na is consistent with  ≈ 16°, which is typical for paragonite, whose interlayer is completely occupied by Na. Chemical composition at the surface was compared to bulk chemical composition obtained by electron microprobe analysis. This comparison highlights a decrease in K content, which can be explained by its location on the cleavage surface, since the cation is expected to be distributed equally along the two surfaces generated after cleavage, and an increase in Na which can be related to Na domains close to the cleavage surface.These aspects may relate muscovite cleavage processes to the presence of “defects”, or better in-homogeneities in layer crystal chemistry. This fact may thus suggest that Na content in paragonitic muscovite could not be only attributed to a solid solution mechanism, where this cation substitutes for K, but rather to the presence of Na-dominant clusters.

C. Elmi; M.F. Brigatti; D. Malferrari ( 2011 ) - Layer charge location in layer silicates and its implications ( Geoitalia 2011 - - 19-23 settembre 2011) ( - Epitome ) - EPITOME - n. volume 4 - pp. da 220 a 220 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

Layer charge value and location are commonly considered key factors for predicting interaction of layer silicates with external agents, such as, for example, pollutants, bio-molecules, and, more generally, ionic complexes. Several methods are discussed in literature for the experimental determination of layer charge, always, however, giving an average value from the different micro-crystals used for the analysis. The most commonly used methods are: the structural formula method [1, 2], the alkylammonium method [3] and the potassium saturation method [4]. The purpose of this paper is to demonstrate that the determination of the average value of the layer charge can sometimes lead to inconsistent results, as not correctly representing the layer charge location at mineral surface. This goal was achieved by analyzing crystal chemical results obtained from different crystals of muscovite characterized by a different content of celadonitic substitution. Muscovite sometimes presents heterovalent substitutions both in tetrahedral (e.g., Al3+ for Si4+) and in octahedral sites (e.g., Mg2+, Fe2+, and vacancies for Al in octahedral sites). Our results seem to demonstrate that these substitutions can be ascribed to trioctahedral cells, all occupied by cations different than Al, in a dominating dioctahedral pattern, with cis-octahedral sites entirely occupied by Al and the trans-site vacant. This interpretation suggests that mean layer charge may not represent effective layer charge at mineral surface because it refers not to randomly distributed substitution, but to domains showing different chemistry which can be locally charge-neutralized. Furthermore, also distortion parameters which affect tetrahedral topology and that can also affect the formation of surface complexes, such as alpha angle and delta z oxygen plane flattening, can be different inside a same structure and locally not corresponding strictly to the determined mean value via single crystal diffraction.

E. Castellini; M. Bert; C. Berthold; M.F. Brigatti; D. Malferrari ( 2011 ) - Sodium hexametaphosfate interactions with illite and montmorillonite: preliminary observation on thermal behavior ( Geoitalia 2011 - - 19-23 settembre 2011) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 4 - pp. da 221 a 221 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

The interaction of an efficient deflocculant, sodium hexametaphosphate (NaHMP), with two different illites (IMt-1 from Silver Hill, Montana USA and from Schwäbisch Hall, Würtenberg Germany) and two different Ca-montmorillonites (STx-1 from Gonzales County, Texas, USA and from Santa Rita, New Mexico, USA) was investigated.Adsorption measurements of the NaHMP anion were performed onNa-exchanged illite IMt-1 as a function of temperature by means of inductively coupled plasma technique (I.C.P.). The thermodynamic parameters of the adsorption process, together with an estimation of the maximum adsorbed amount on the Na-illite were obtained and compared to the corresponding data previously obtained for Na-kaolinite.The effect of NaHMP on the natural illites and montmorillonites was analyzed using different techniques. I.C.P. measurements of the concentration of P, Na, Si, Al, Ca, Mg, and K of the deflocculant solutions in contact with the clays were performed in order to detail the adsorption, dissolution and exchange phenomena which accompany the deflocculant activity.Thermal analysis (thermo-gravimetric, thermal-differential) and XRD measurements at non ambient temperature conditions were used to characterize the clay solid samples after the interaction with NaHMP.Thermo-gravimetric analyses indicate that NaHMP-treated illites and montmorillonites are less hydrated than natural samples, whereas the dehydroxilation reaction seems to be not influenced by the NaHMP treatment. Basal periodicity was measured via XRPD diffraction on (00l) oriented mounts of the air-dried samples in the temperature range 25 - 400°C (heating rate 2 °C/min) using a powder diffractometer equipped with an area detector. No significant variation of layer periodicity was observed, thus indicating that NaHMP molecules are adsorbed on the edge and/or in the interlayer without modifying natural layer periodicity.

A. Laurora; M.F. Brigatti; D. Malferrari; E. Galli; A. Rossi; M. Ferrari ( 2011 ) - Crystal chemistry of lizardite-1T from Northen Apennines Ophiolites (Italy) ( Geoitalia 2011 - - 19-23 settembre 2011) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 4 - pp. da 220 a 220 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

This study investigates the crystal chemical features of six lizardite-1T crystals sampled in four ophiolitic outcrops (Pompeano, Sassomorello, Varana, and Santa Scolastica) in the Modena Apennines (Italy).Notwithstanding the extensive contributions already present in literature, this is the first study dealing with lizardites from Modena ophiolites. As evidenced by one of our samples, the whole rock composition affects lizardite composition, which results to be sensible to the overprint of secondary, metasomatic events. In our study, particular attention was devoted to the effects of octahedral Fe for Mg and of Si-1Al(Mg,Mn,Fe)2+-1 (Al,Cr,Fe)3+ exchange mechanisms on the structure. Our results suggest that Fe for Mg substitution induces an increase in the octahedral M-O4 length, and a decrease in the octahedral site distortion. Both these effects are also observed to influence unit-cell parameter c. The effect of the Si-1 Al(Mg,Mn,Fe)2+-1(Al,Cr,Fe)3+ substitution is a decrease in the M-O1 distance and a concomitant increase in the T-O1 distance.

D. Malferrari; M.F. Brigatti; A. Laurora; R. Sassi; F.P. Sassi ( 2011 ) - Textural study of metamorphic rocks by means of a conventional X-ray source ( Geoitalia 2011 - - 19-23 settembre 2011) ( - Epitome ) (FIST udine ITA ) - EPITOME - n. volume 4 - pp. da 221 a 221 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

The aim of this study is the textural characterization of very low togreenschist facies metamorphic rocks by means of a conventional X-ray source, possibly establishing a relationship between the extent of morphological orientation of mineral grains and metamorphic degree.For a long time geologists investigated the morphological orientation of mineral grains in polycrystalline rocks by means of petrographic microscope equipped with a Universal stage. More recently diffraction of conventional X-ray sources as well as diffraction (or transmission) of hard X-rays, electrons and neutrons has been applied to these kind of study.However, whereas X-ray conventional sources can be regarded as a routine technology, hard X-ray, electron and neutron sources are only available in a few facilities around the world.Phyllosilicates such as smectite, illite, muscovite, chlorite and biotite play a key role in the textural characteristics of the mineral assemblages of rocks characterized by increasing metamorphic degree. The present study is focused on the variation of the X-ray intensities of selected reflections of these phases. In short, if a morphologic orientation of the grains of a certain phyllosilicate is present, a variation of the intensity of these reflections will be measured when the rock sample is rotated in a goniometer keeping constant both the incident beam angle and the position of the detector.The samples selected for the study are the following: 1) a Ms, Chl, Qtz, Pl fine grained metapelite from Frassenetto (UD, Italy) (very low grade metamorphism, Anchizone) with some detrital muscovite flakes recognizable by their coarser grain size; 2) Ms, Chl, Qtz, Pl fine grained metapelite from Chiadenis (UD, Italy) (low grade metamorphism, Epizone) with some detrital muscovite flakes recognizable by their coarser grain size; 3) a Ms, Chl, Ilm, Qtz, Pl layered phyllite from Villabassa (BZ, Italy) (Greenschist facies metamorphism, Ms-Chl-Bt), with crenulated main foliation and axial planes defining a second spaced foliation; 4) a Ms, Bt, Grt, Ilm, Qtz, Pl layered phyllite from Luson (BZ, Italy) (Greenschist facies metamorphism, Ms-Bt-Grt), with crenulated main foliation and axial planes defining a second spaced foliation.

Brigatti M.F.; Malferrari D.; Laurora A.; Elmi C. ( 2011 ) - Structure and mineralogy of layer silicates: recent perspectives and new trends ( EMU School 2001 - - 9-19 luglio 2011) ( - Book of Abstract ) (Brigatti M.F., Mottana A. Modena e Roma ITA ) - pp. da 5 a 5 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Layer silicates are experiencing an increasing interest from the scientific and technical community, in relation to their application in many novel and advanced areas. The correct application of these minerals requires a deep understanding of their properties and of the processes where they are involved. This chapter, by providing fundamental denitions and data pertaining to layer silicates, is aimed at introducing into this eld a novel or yet experienced researcher or technician, thus describing the fundamental features leading to dierent layer silicates behaviour in dierent natural or technical processes, as better detailed in other chapters of this book. The matter addressed is extremely vast, thus suggesting to condensate or to omit more consolidated knowledge, already available to the reader via numerous review works and volumes, quoted in this chapter.More details were provided on minerals being characterized by applicative signicance or by a greater amount of information available in literature on their crystal structure and chemistry.

Bortolotti D.; Brigatti M.F.; Elmi C.; Malferrari D.; Pattuzzi E. ( 2010 ) - Relationship between morphological preferred orientations and landslides ( IMA 2010, 20th General Meeting of the International Mineralogical Association - - 21-27 Agosto 2010) ( - Mineralogica-Petrographica Abstract Series ) - n. volume 6 - pp. da 856 a 856 ISSN: 1589-4835 [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

Crystals orientation in polycrystalline natural compounds maybe either completely random or else follow preferred directions,which reflect physical processes in which the materials havebeen involved during the solidification and / or after the solidstate had been reached.The preferred orientation can be divided into two maingroups: i) preferred orientation of the crystal lattice (LPO,lattice preferred orientation) and ii) grains preferred orientation(i.e., morphological preferred orientations, MPO). Frequentlythere is a close relationship between these two groups.Geological processes that determine the formation of LPO are,for example, tectonic (regional) compressive movements; on theother hand MPO can be induced also by local stress (i.e.,gravitational movements). While tectonic (regional)compressive movements may produce LPO even on alreadylithified rocks, usually, MPO are induced only on not-lithifiedand incoherent rocks.The preferred orientation cab be observed: i)macroscopically (the rock structures) ii) microscopically, grainsorientation and morphological textures of the rock according tothe classic concept of optical microscopy, iii) with diffractionmethods (i.e., X-rays and neutrons diffraction), to study bothLPO and MPO when, this last, cannot be studied via opticalmethods because, for example, of a very small grain size.This research will investigate MPO via X-ray diffractiononly. We collected, and kept oriented, samples in severallandslide areas. In particular samples were collected both in theactive crumbling area and at the landslide margin. Sampleswere analyzed for texture using X-ray diffractometer equippedwith a phi-chi Eulerian cradle. We analyzed the preferredorientation of the hkl reflections: i) (001) and (060) in smectitiand illite; ii) (001) and (100) in caolinite; iii) (24-1) inplagioclase.Preliminary investigation demonstrated a direct correlationbetween the number of MPO and the amount of clay minerals.Texture measurements on samples collected in the crumblingarea agree with other morphological field measurements,providing, in addition to the main direction of the landslide, alsothe vertical module, thus probably defining the preferential pathfor interstitial fluids migration. Only in one case we couldobserve preferred orientation in a sample coming from a marginof a landslide, data which could testify a past movement (paleolandslide) or else a quiescent landslide.

Elmi C.; Brigatti M.F.; Malferrari D.; Castro G.R.; Ferrer Escorihuela P. ( 2010 ) - Surface structure of natural muscovite ( IMA 2010, 20th General Meeting of the International Mineralogical Association - - 21-27 Agosto 2010) ( - Acta Mineralogica-Petrographica Abstract Series ) - n. volume 6 - pp. da 753 a 753 ISSN: 1589-4835 [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The aim of this project is to study the atomic surface structure of a natural muscovite crystal thanks to the synchrotron radiation light and the grazing incidence X-ray diffraction (GIXRD).The muscovite studied [(K0.92Na0.08) (Al1.86Fe3+0.01Mg.0.07 Fe2+0.06Ti0.02) (Si3.03Al0.97) O10 F0.09 (OH)1.91] is monoclinic, 2M1 polytype, with symmetry C2/c and unit cell parameters a = 5.19690(10) b = 9.0138(3) c = 20.0835(7) (Å) and β = 95.763(2) (°).The muscovite structure was refined by single crystal X-ray diffraction and the final refinement yielded the following agreement factor R = 0.0299. The difference Fourier map shows a significant residual electron density (2.2-) close to the position related to M1 site, thus indicating that the excess of octahedral cations is located at M1. M1-O mean bond distance is 2.247(9) and M2-O distance is 1.929.Grazing incidence X-ray diffraction (GIXRD) was recently performed at SpLine at ESRF. This type of analysis is very useful to identify typical structural features of the surface, such as possible imperfections, relaxations or reconstructions. Usually, the atoms on surfaces, and sometimes those as deep as several layers down, assume positions different from their equilibrium positions in the bulk. Generally mineral surfaces will not be reconstructed unless they have been heated to temperature higher than 100 °C. In our case, the muscovite surface has been exposed to a delay of the first layer in order to study a freshly cleaned surface and data collected by GIXRD confirm that on muscovite surface only a relaxation occurs from an equivalent plane in the bulk. This is a common case for minerals with a low-symmetry structure as the feldspar surface.

Affronte M.; Brigatti M.F.; Malferrari D.; Marcelli A.; Pini S. ( 2010 ) - Trioctahedral micas: relationships between crystal chemistry and magnetic behavior ( IMA 2010, 20th General Meeting of the International Mineralogical Association - - 21-27 Agosto 2010) ( - Acta Mineralogica-Petrographica Abstract Series ) - n. volume 6 - pp. da 852 a 852 ISSN: 1589-4835 [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

This study is aimed at verifying the factors affecting magneticsusceptibility χ variation in micas in relation to: I) Fe content;ii) Fe2+/Fe3+ ratio; iii) occurrence of Fe in tetrahedral andoctahedral sites, outlining possible ordering effects.Other aspects considered in our study will involve: i)eventually observed variation in magnetic properties forsamples showing similar chemical composition, but occurringfrom different areas and different crystallization environments;ii) possible influence of strong magnetic anomalies overmagnetic properties of samples therein occurring.All these aspects were thus addressed by characterizingsamples belonging to phlogopite – annite, tetra-ferriphlogopite– tetra-ferri-annite and polylithionite – siderophylliteseries. Some samples, representative of the whole sample set,were then selected for magnetic susceptibility characterization.Some of them also required calorimetric analyses, in order tobetter describe and understand their behaviour.Other experimental methods used in this investigationinclude: electron microprobe, structure resolution by X-raysingle crystal methods, X-ray absorption spectroscopy, with aparticular attention to the understanding of the XANES region.Main results demonstrate that: i) magnetic phenomenaassociated with maxima of magnetic susceptibility could beobserved at low temperature (T<10 K) and weak magnetic field(10 Oe); ii) magnetic properties depend not only on the total Fecontent. Samples where Fe is mostly in octahedral coordinationare predominantly ferromagnetic, strongly depending on the[6]Fe2+/([6]Fe2++[6]Fe3+) ratio, which was observed to increasewith Curie-Weiss θ constant (ranging from 13 to 24 K and from4.4 and 5.2 K for samples showing higher and lower[6]Fe2+/([6]Fe2++[6]Fe3+) ratio, respectively). In tetra-ferriphlogopite,dominant interactions were observed to be antiferromagnetic,as shown by a negative Curie-Weiss θ constantvalue (-25 K). Furthermore Curie-Weiss constant (θ) and thetemperature value giving the maximum in the magneticsusceptibility (Tm) seem to be dependent not only on the meannumber of Fe atoms in octahedral coordination (Z) per unit cell,but also on its ordering. Tm linearly depends on severalstructural parameters as well, e.g., the tetrahedral rotation angle α.

Malferrari D.; Brigatti M.F.; Marcelli A.; Chu W.; Wu Z. ( 2010 ) - Effect of temperature on Hg-cysteine complexes in vermiculite and montmorillonite ( IMA 2010, 20th General Meeting of the International Mineralogical Association - - 21-27 Agosto 2010) ( - Acta Mineralogica-Petrographica Abstract Series ) - n. volume 6 - pp. da 852 a 852 ISSN: 1589-4835 [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

This work describes the influence of temperature on two Hg(II)-cysteine modified clay minerals with different layer charge (i.e.,vermiculite and montmorillonite) by using chemical analyses,thermal analyses coupled with evolved gas mass spectrometry(TGA-MSEGA), synchrotron-based X-ray absorptionspectroscopy (XAS), and X-ray powder diffraction (XRPD)techniques. These two latter techniques were applied onsamples heated “in situ” up to 900°C. Hg binds cysteine by thethiol group with Hg–SH bond lengths similar in both clayminerals, thus suggesting their independence from layer charge.On the contrary, the thermal behaviour of the adsorbedorganometallic complexes is strictly layer charge dependent, asevidenced by decomposition temperatures, which are commonlylower in montmorillonite than in vermiculite. Results from Xrayabsorption near edge structure (XANES) spectroscopyevidence a nearly completely Hg removal in montmorillonite attemperature values ranging from 600 to 700°C, unlike invermiculite where Hg is still present at these temperatures.

Marchetto P.; Brigatti M.F.; Laurora A.; Malferrari D. ( 2010 ) - Use of perlite in combination with clays for the production of low environmental impact filter for heavy metals polluted aqueous solution ( IMA 2010, 20th General Meeting of the International Mineralogical Association - - 21-27 Agosto 2010) ( - Acta Mineralogica-Petrographica Abstract Series ) - ACTA MINERALOGICA-PETROGRAPHICA. ABSTRACT SERIES - n. volume 6 - pp. da 14 a 14 ISSN: 1589-4835 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

The aim of this work is to prepare a relatively cheap mixture ofperlite (a volcanic rock with intermediate composition betweenrhyolite and dacite) and clays, effective in the retention of heavymetals even after treatments at relatively high temperatures. Theobtained product could be possibly reused and therefore notdisposed of as toxic waste. The perlite used in this study comesfrom Greek quarries and is provided by the company "PerliteItaliana”. Three different types of clay materials were used: 1) aclay material coming from the Argille Varicolori formation; 2) acommercial bentonite (supplied by Laviosa, Italy; 3) a standardmontmorillonite (STx-1, from the County of Gonzales, Texas,USA), to be used as reference materials.Column and batch tests were carried out on several differentmixtures of the previously described materials in order toevaluate the effective adsorption of Cd, Pb, and Zn fromaqueous solution. Pb, Zn, and Cd contents of the “polluted”mixtures were thus measured via inductively coupled plasmaoptical emission spectroscopy (ICP-OES) after acid digestion.The obtained results indicate that the mixture consisting ofVaricolori clay and perlite can be profitably used as adsorbentof metals in solution. Adsorption data are consistent with thoseexpected from theoretical calculations.The method chosen for the permanent inertization ofpolluted samples is thermal treatment, which, as evidenced bynumerous literature data, can lead to a chemically inert product,eventually suitable for reuse in construction. Before being fired,each mixture was added from opportune amount of kaoliniteand feldspar. Release tests were, thus, carried out on firedproducts using weakly acid solution (pH values between 5.5.and 6) as leaching media. Results, which are very encouraging,are reported in the Table 1.

Elmi C.; Brigatti M.F; Pasquali L.; Montecchi M.; Nannarone S.; Laurora A.; Malferrari D. ( 2010 ) - The relationships of bulk structure, surface structure, chemistry, and physical properties of mineral phases with six- and eight-membered silicate rings ( IMA 2010, 20th General Meeting of the International Mineralogical Association - - 21-27 Agosto 2010) ( - Acta Mineralogica-Petrographica Abstract Series ) - n. volume 6 - pp. da 710 a 710 ISSN: 1589-4835 [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The goal of this research is to better understand the relationship between chemical composition and atomic structure (both bulk and surface structure) of minerals having six-membered silicate rings, such as osumilite and eight-membered silicate rings, such as vesuvianite. Osumilite under investigation occurs in thin fissures within a rhyolite from the volcanic massif of Mt. Arci, Sardinia (Italy). Vesuvianite sample is from skarns of Somma-Vesuvius volcano (Italy) instead.The osumilite and vesuvianite bulk structures were refined via single crystal X-ray diffraction. Osumilite sample is hexagonal, with symmetry P6/mcc and unit cell parameters a = 10.1550(6) c = 14.306(1) (Å). The structural formula is (K0.729)C (Na0.029)B’ (Si10.498 Al1.502)T1 (Al2.706 Fe2+0.219 Mg0.075)T2 (Mg0.660 Mn0.091 Fe2+1.258)AO30. When compared to literature data [1], osumilite sample from Mt. Arci is characterized by a significantly high Fe2+ content (1.478 apfu).X-ray photoelectron spectroscopy (XPS) enabled the crystal chemical characterization of osumilite surface, where iron was still observed in its divalent state, thus confirming a similarity in osumilite surface and bulk chemical composition. A further evidence of Fe oxidation state at osumilite surface is provided from X-ray absorption spectroscopy (XAS) at Fe-L2,3 edge.Vesuvianite is a complex tetragonal silicate. Vesuvianite ideal formula is Ca19(Al,Mg)13(B, Si)18O68(OH, O, F)10 and crystallizes, generally, in the space group P4/nnc. Vesuvianite presents in nature two different structural type: a high temperature type (at about 1000 °C) and a low temperature type (at about 900 °C). To recognize which type of vesuvianite, our sample belongs to, we studied its thermal decomposition via X-ray powder diffraction method by using a Philips X’Pert PRO diffractometer equipped with X’Celerator area detector. Finally we could assure that our sample is a high temperature vesuvianite with high symmetry P4/nnc.Unlike osumilite, vesuvianite surface is very complex to study because of its roughness on given faces of the crystal. However we could obtain preliminary information on the chemical composition of the surface via XPS and subsequently compare these data to bulk chemical composition. Moreover, unlike osumilite sample, vesuvianite presents Fe in octahedral site both in divalent and trivalent state, as confirmed by XAS experiments performed at the L2,3 edge of iron.

M.F. Brigatti; C. Elmi; A. Laurora; D. Malferrari; L. Medici ( 2009 ) - Combined mineralogical and EXAFS characterization of polluted sediments for the definition of technological variables and constraints ( EGU2009 - - 19-24 Aprile 2009) ( - Geophysical Research Abstracts ) - GEOPHYSICAL RESEARCH ABSTRACTS - n. volume 11 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

An extremely severe aspect, both from environmental and economic viewpoint, is the management of pollutedsediments removed from drainage and irrigation canals. Canals, in order to retain their functionality over the time,need to have their beds, periodically cleaned from sediments there accumulating. The management of removedsediments is extremely demanding, also from an economical perspective, if these latter needs to be treated asdangerous waste materials, as stated in numerous international standards. Furthermore the disposal of such a largeamount of material may introduce a significant environmental impact as well. An appealing alternative is the recoveryor reuse of these materials, for example in brick and tile industry, after obviously the application of appropriatetechniques and protocols that could render these latter no longer a threat for human health. The assessment ofthe effective potential danger for human health and ecosystem of sediments before and after treatment obviouslyrequires both a careful chemical and mineralogical characterization and, even if not always considered in the internationalstandards, the definition of the coordination shell of heavy metals dangerous for human health, as afunction of their oxidation state and coordination (e.g. Cr and Pb), and introducing technological constraints oraffecting the features of the end products. Fe is a good representative for this second category, as the features ofthe end product, such as color, strongly depend not only from Fe concentration but also from its oxidation state,speciation and coordination. This work will first of all provide mineralogical characterization of sediments fromvarious sampling points of irrigation and drainage canals of Po river region in the north-eastern of Italy. Sampleswere investigated with various approaches including X-ray powder diffraction under non-ambient conditions, thermalanalysis and EXAFS spectroscopy. Obtained results, and in particular EXAFS spectra were used to define andoptimize the technological variables of the recovery process.

Malferrari D.; Brigatti M.F.; Laurora A.; Zanerini L. ( 2009 ) - Natural Reserves as a tool for the recovery and exploitation of abandoned mining areas: Hg in soils and sediments from Pigelleto (Piancastagnaio, Siena, Italy) Natural Reserve ( Geoitalia 2009 7° Forum Italiano di Scienze della Terra - - 09-11 Settembre 2009) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 3 - pp. da 25 a 25 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

nd

Malferrari D.; Brigatti M.F.; Laurora A.; Venturini S. ( 2009 ) - Mobilization of heavy metals from fluvial sediments (Tiepido river, Modena, Italy): mineralogical and chemical investigation to prevent potential environmental hazard ( Geoitalia 2009 7° Forum Italiano di Scienze della Terra - - 09-11 Settembre 2009) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 3 - pp. da 100 a 100 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

nd

Laurora A.; Malferrari D.; Brigatti M.F.; Mottana A.; Caprilli E.; Giordano G.; Funiciello R. ( 2009 ) - Crystal chemistry of trioctahedral micas in the top sequences of the Colli Albani volcano, Roman Region, Central Italy ( Geoitalia 2009 7° Forum Italiano di Scienze della Terra - - 09-11 Settembre 2009) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 3 - pp. da 17 a 17 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

Trioctahedralmicacrystals are frequently found in the volcanoclastic products emplaced during the final stages of the activity of the ColliAlbanivolcano (RomanRegion, centralItaly). In the youngest phreatomagmatic deposits, mica is found either as a minor mineral phase in holocrystalline ejecta, scoriae, and coherent pyroclastics, or as loose phenocryst in incoherent pyroclastics. Based on optical and electron microscope investigations, as well as crystal chemical and structural data, the micas selected for this study were divided into two groups, the first one encompassing brownish, Fe-rich crystals (type-A phlogopites, hereafter referred as t-A) with 0.68 < Mg/(Mg + Fetotal) < 0.85 and 0.062 < Tiapfu < 0.199, and the other one encompassing colorless, Mg-rich crystals (type-B phlogopites, hereafter referred as t-B) with Mg/(Mg + Fetotal) in excess of 0.85 and 0.007 < Tiapfu < 0.052. t-A phlogopites also show a tetrahedral ring cavity, overlapped tetrahedral hexagon area, and basal tetrahedron area greater than in the t-B phlogopites.From a petrological point of view, the textural and chemical variations of t-A phlogopites are compatible with fractional crystallization processes taking place within the magma chamber. t-B phlogopites show evidence of a Ti-oxy substitution mechanism, thus suggesting high fO2 conditions. Textural and paragenetic features observed in t-B phlogopite-bearing rock samples, indicate a genesis by thermal metamorphism of a siliceous dolomitic limestone with the input of a variable amount of a potassic magma, possibly the same from which the t-A phlogopites formed, with the exception of one sample, for which a different parental magma is suggested. Indeed, there is an almost continuous spectrum of crystal-chemical and structural parameters starting from t-B and evolving towards t-A phlogopites. The t-A phlogopites displays complex, apparently meaningless relationships in their crystal-chemical parameters, thus indicating interplay of several substitution mechanisms. They possibly formed in polybaric conditions, since their cell volumes differ, but the total size of the cations hosted in the octahedral sheet is the same

Elmi C.; Brigatti M.F; Pasquali L.; Montecchi M.; Laurora A.; Malferrari D.; Nannarone S. ( 2009 ) - Osumilite from Mount Arci (Sardinia, Italy): bulk and surface crystal chemistry ( Geoitalia 2009 7° Forum Italiano di Scienze della Terra - - 09-11 Settembre 2009) ( - Plinius ) - PLINIUS - n. volume 35 - pp. da 744 a 745 ISSN: 1972-1366 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

This study is focused on osumilite crystal chemistry and on its surface chemical characteristics and properties. Osumilite belongs to the milarite mineral group. This mineral, with the ideal formula XIICIXB’2VIA2(T2)3IV(T1)12O30 crystallizes in the space group P6/mcc. T1 is mainly occupied by Si and to a smaller amount by Al, T2 is usually occupied by Al with Fe and little Mg, whereas A octahedron mostly contains Mg and Fe. The ring arrangement defines structural channels occupied by the twelve-coordinated C site which is characterized by the presence of alkaline cations (Na, K).The osumilite from Mt Arci (Sardinia) occurs in thin fissures and small cavities within a rhyolite from the volcanic massif of Mt. Arci, Sardinia. The mineral forms regular dark blue hexagonal prismatic-tabular crystals associated to trydimite and sporadic phlogopite crystals. The osumilite structure was refined by single crystal X-ray diffraction and the final refinement yielded the following agreement factors R = 0.0199. The sample studied is hexagonal, with symmetry P6/mcc and unit cell parameters a = 10.1550(6) c = 14.306(1) (Å). The structural formula is (K0.729)C (Na0.029)B’ (Si10.498 Al1.502)T1 (Al2.706 Fe2+0.219 Mg0.075)T2 (Mg0.660 Mn0.091 Fe2+1.258)AO30. In respect of data from literature [2], osumilite sample from Mt. Arci is characterized by a significantly high Fe content (1.478 apfu).In order to study the morphology of osumilite from Mt. Arci, an atomic force microscopy (AFM) filtered images of osumilite was performed. The (001) surface roughness of osumilite is about 0.40 nm, thus it confirms the presence of the channels defined by the double rings of tetrahedra. The distance between two dark areas, defining channel position, is 1 nm, which well agree with the unit cell parameter a value.X-ray photoelectron spectroscopy (XPS) analysis was carried out to measure chemical composition and quantity of each element on the osumilite surface. Higher resolution spectra in the region of Si2p, Al2p, Mg1s and Fe2p core levels were measured. From data collected, we could say that the osumilite surface is chemically well characterized and the elemental composition of surface totally corresponds to the bulk chemical composition. Moreover, comparing our results to data from literature we obtained also crystal chemical information on Fe, Mg, Si and Al high resolution spectra, compared to the crystal chemical characteristics of the bulk.In order to confirm the valence of Fe and the position of this element in the A site, X-ray absorption spectroscopy (XAS) was also made in the L2,3 edge of iron comparing data from literature.

Pini S.; Affronte M.; Brigatti M.F.; Malferrari D.; Marcelli A. ( 2009 ) - Octahedral cation ordering and magnetic behavior of micas ( Geoitalia 2009 7° Forum Italiano di Scienze della Terra - - 09-11 Settembre 2009) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 3 - pp. da 13 a 13 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

This contribution is finalized at the discussion of the magnetic structure of two samples, belonging to phlogopite–annite [sample TK, chemical composition IV(Si2.76Al1.24) VI(Al0.64Mg0.72 Fe1.452+ Mn0.03Ti0.15) (K0.96Na0.05) O10.67 (OH)1.31 Cl0.02] and polylithionite–siderophyllite joints [sample PPB, chemical composition IV(Si3.14Al0.86)VI(Al0.75Mg0.01 Fe1.032+ Fe1.033+ Mn0.01Ti0.01Li1.09) (K0.99Na0.01) O10.00 (OH)0.65F1.35]. Samples differ for Fe ordering in octahedral sites, Fe2+/(Fe2+ + Fe3+) ratio, octahedral composition, defining a different environment around Fe cations, and layer symmetry. Spin-glass behavior was detected for both samples, as evidenced by the dependency of the temperature giving the peak in the susceptibility curve from the frequency of the applied alternating current magnetic field. The crystal chemical features are associated to the different temperature at which the maximum in magnetic susceptibility is observed: 6 K in TK, where Fe is disordered in all octahedral sites, and 8 K in PPB sample, showing a smaller and more regular coordination polyhedron for Fe, which is ordered in the trans-site and in one of the two cis-sites.

Elmi C.; Brigatti M.F; Malferrari D.; Castro G.R.; Ferrer-Escorihuela P.; Rubio-Zuazo J. ( 2009 ) - Relationship between bulk and surface structure of muscovite ( Geoitalia 2009 7° Forum Italiano di Scienze della Terra - - 09-11 Settembre 2009) ( - Epitome ) - EPITOME - n. volume 3 - pp. da 15 a 15 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

The aim of this project is to study the relationships between bulk and surface structure of a natural muscovite crystal.The muscovite studied [(K0.92Na0.08) (Al1.86Fe3+0.01Mg.0.07 Fe2+0.06Ti0.02) (Si3.03Al0.97) O10 F0.09 (OH)1.91] is monoclinic, 2M1 polytype, with symmetry C2/c and unit cell parameters a = 5.19690(10) b = 9.0138(3) c = 20.0835(7) (Å) and β = 95.763(2) (°).The muscovite structure was refined by single crystal X-ray diffraction and the final refinement yielded the following agreement factor R = 0.0299. The difference Fourier map shows a significant residual electron density (2.2-) close to the position related to M1 site, thus indicating that the excess of octahedral cations is located at M1. M1-O mean bond distance is 2.247(9) and M2-O distance is 1.929.Grazing incidence X-ray diffraction (GIXRD) was recently performed at SpLine at ESRF. This type of analysis is very useful to identify typical structural features of the surface, such as possible imperfections, relaxations or reconstructions of the surface [1]. Preliminary data collected by GIXRD could indicate that on muscovite surface a reconstruction could occur, but we need more reflections to be certain of this assumption. Some indirect evidence of surface modification of mica crystals may be suggested by a lower K content on mica surface than observed in the bulk, which is a rather common observation when subjecting micas to chemical analyses. K release can also be attributed to a variation of interlayer cavity topology at surface, as well as to a breaking of K-O bonding. This effect can play a significant role in determining surface charge in micas, either completely negative, or partly positive and partly negative, depending on K release.

Malferrari D ; Brigatti MF ; Laurora A ; Pini S ( 2009 ) - Heavy metals in sediments from canals for water supplying and drainage: mobilization and control strategies - JOURNAL OF HAZARDOUS MATERIALS - n. volume 161 - pp. da 723 a 729 ISSN: 0304-3894 [Articolo in rivista (262) - Articolo su rivista]
Abstract

One of the most critical aspects of the maintenance of canals forwater supplying and drainage is the managingof deposited sediments, which must be periodically removed. Deposited sediments, if containinganthropogenic pollutants with a concentration exceeding specific law limits, must be stored as industrialwastes, thus raising additional economic and logistic problems to deal with. Our research considers pollutedsediments from an area close to the south side of Po river, in order to characterize heavy metalsassociated with different mineral species, thus defining effective treatments for their inertization, andsuggesting a possible process for their recycle. Our results demonstrate that the composition of thesesediments is suitable for the production of tiles and bricks. Several testswere thus performed to optimizesample treatment and other process parameters, finally giving very encouraging results. Releasing testson fired products reveal that all the heavy metals are well retained.

Elmi C.; Brigatti M.F; Malferrari D.; Valdrè G.; Castro G.R.; Rubio-Zuazo J. ( 2008 ) - Clinochlore structure and its surface interactions with organic molecoles ( 1st SIMP-AIC Joint Meeting - - 07-12 Settembre 2008) ( - Book of Abstract ) (Società Italiana di Mineralogia e Petrologia Pisa ITA ) - pp. da 197 a 197 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

This study is focused on clinochlore crystal chemistry and on its surface interactions with biomolecules. Clinochlore, which is a chlorite, is formed by two different polyhedral units: (i) two tetrahedral sheets (T) sandwiching a Mg-rich octahedral sheet (O) and (ii) an octahedral Mg-, Al-rich, brucite-like, interlayer (B). The excess of negative charge of the TOT layer is neutralized by the positively charged B interlayer. Extensive hydrogen bonding provides structural cohesion between the TOT layer and the B interlayer.The clinoclhore studied is triclinic IIb-4 polytype, with symmetry C and unit cell parameters a = 5.3301(4) b = 9.2511(6) c = 14.348(1) (Å) α = 90.42(1) β = 97.51(1) γ = 90.00(2) (°). The chemical composition is [VI](Mg9.6Fe2+0.27Al2.01Cr0.09)[IV](Si5.86Al2.14)O20(OH)16.Measurements of surface reflectivity carried out at ESRF, Spanish beam line, suggest that biological molecules, such as nucleotides, can be adsorbed as (001) organized layer on the mineral surface. Furthermore AFM (Atomic Force Microscopy) and EFM (Electric Force Microscopy) studies suggest that clinochlore presents at the nanoscale, negative regions of exposed oxygens (tetrahedral sheets, lower layer) and positive regions of exposed hydroxyl groups belonging to the brucite-like which is about 0.5 nm thick [1]: the brucite-like layer is more effective in assembling the biological molecules rather than the exposed oxygen surface.

Malferrari D; Brigatti MF; Marcelli A; Chu W; Wu Z ( 2008 ) - Modification of Hg complexes in layered silicates with temperature: an in situ XAS study - MICROPOROUS AND MESOPOROUS MATERIALS - n. volume 107 - pp. da 128 a 133 ISSN: 1387-1811 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work will address the thermal evolution (variation in oxidation state, disproportionation reactions) of Hg(II), adsorbed by two different layer silicates (montmorillonite and vermiculite) via XAS spectroscopy at increasing temperature. From the XANES analysis we could recognize significant structural differences between Hg-treated montmorillonite and vermiculite even at room temperature. At increasing temperature Hg is not easily removed from the silicate layer and it could be identified in layer structure up to T = 400 °C in montmorillonite and up to T = 700 °C in vermiculite. Furthermore, it is evident from EXAFS spectra collected at room temperature that Hg–H2O complexes are present in both montmorillonite and vermiculite, whereas the HgO form appears only in vermiculite.

Valdrè G.; Brigatti M.F.; Malferrari D. ( 2008 ) - DNA interactions with clinochlore surface ( II International Workshop of Layered Materials - - 28-30 Marzo 2008) ( - Book of Abstract ) (Università del Piemonte Oritentale e Università di Torino Torino ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Brigatti M.F.; Malferrari D.; Mottana A.; Cibin G.; Marcelli A.; Cinque G. ( 2008 ) - Crystal chemical modeling and XANES spectroscopy of potassium micas ( II International Workshop of Layered Materials - - 28-30 Marzo 2008) ( - Book of Abstract ) (Università del Piemonte Orientale e Università di Torino Torino ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Brigatti M.F.; Caprilli E.; Malferrari D.; Mottana A. ( 2008 ) - The octahedral anionic site in micas: a comparison between fluorannite and annite ( II International Workshop of Layered Materials - - 28-30 Marzo 2008) ( - Book of Abstract ) (Università del Piemonte Orientale e Università di Torino Torino ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Valdrè G.; Moro D.; Malferrari D.; Brigatti M.F. ( 2008 ) - Kelvin probe and surface shear microscopy of layer silicates ( II International Workshop of Layered Materials - - 28-30 Marzo 2008) ( - Book of Abstract ) (Università del Piemonte Orientale e Università di Torino Torino ITA ) - pp. da 4 a 4 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Medici L.; Brigatti M.F.; Malferrari D. ( 2008 ) - X-ray microdiffraction as a tool for single crystal structure refinement: a study on apatite crystals ( 1st SIMP-AIC Joint Meeting - - 07-12 Settembre 2008) ( - Book of Abstract ) (SIMP Pisa ITA ) - pp. da 102 a 102 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Poster

Malferrari D.; Brigatti M.F.; Elmi C.; Marcelli A.; Chu W.; Wu Z. ( 2008 ) - Effect of temperature on Hg- and Hg-cysteine complexes in vermiculite and montmorillonite interlayer ( 1st SIMP-AIC Joint Meeting - - 07-12 Settembre 2008) ( - Book of Abstract ) (Società Italiana di Mineralogia e Petrologia Pisa ITA ) - pp. da 187 a 187 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Presentazione orale

M. BRIGATTI; MALFERRARI D; POPPI M; MOTTANA A; CIBIN G; MARCELLI A; CINQUE G ( 2008 ) - Interlayer potassium and its neighboring atoms in micas: Crystal chemical modeling and XANES spectroscopy - AMERICAN MINERALOGIST - n. volume 93 - pp. da 821 a 830 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The aim of this work is to provide a detailed description of the interlayer site in trioctahedral true micas by combining crystal-chemical and spectroscopic evidence. Insights obtained are based on a statistical appraisal of crystal-chemical, structural and spectroscopic data determined on two sets of trioctahedral micas extensively studied by both X-ray diffraction refinement on single crystals (SC-XRD) and X-ray absorption fine spectroscopy (XAFS) at the potassium K-edge. Spectroscopy was carried out on both random powders and oriented cleavage flakes, the latter setting taking advantage of the polarized character of synchrotron radiation. Such an approach (AXANES) is shown to be complementary to crystal-chemical investigation based on SC-XRD refinement. However, the results are not definitive as they focus on few samples having extreme features only (e.g., end-members, unusual compositions, and samples with extreme and well-identified substitution mechanisms). The experimental absorption K-edge (XANES) was decomposed by calculation and extrapolated into a full in-plane absorption component and a full out-of-plane absorption component. These two patterns reflect different structural features: represents the arrangement of the atoms located in the mica interlayer space and facing tetrahedral sheets; is associated to multiple-scattering interactions entering deep into the mica structure, thus reflecting also interactions with the heavy atoms (essentially Fe) located in the octahedral sheet. The out-of-plane patterns also reflect somewhat the octahedral atoms electronic properties, such as their oxidation states (e.g., Fe2+ and Fe3+) and their ordering (e.g., trans- vs. cis-setting). Distinction between fluoro- and hydrous micas is also possible due to peculiar absorption features originating from the F vs. OH occupancy of the O4 octahedral site. Thus, combining structural and spectroscopic information is shown to be a practical method that allows, on one hand, assigning the observed spectroscopic features to precise structural pathways followed by the photoelectron within the mica structure and, on the other hand, clarifying on the amount of electronic interactions and forces acting onto the individual atoms at the various structural sites.

P. Marchetto; A. Laurora; D. Malferrari; M.F. Brigatti; G. Bosi ( 2008 ) - I suoli a mirtillo (Appennino Modenese) ( Il mirtillo nero del Frignano - - 25 Maggio 2007) - ATTI DELLA SOCIETÀ DEI NATURALISTI E MATEMATICI DI MODENA - n. volume 138 (suppl.) (2007) - pp. da 63 a 93 ISSN: 0365-7027 [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

Lo scopo dello studio è di verificare se la crescente diffusione di falso mirtillo nei vaccinieti spontanei del territorio del Frignanp (Alto Appennino modenese) sia correlata con la variazione delle caratteristiche chimico-ficsiche del suolo.

Brigatti MF; Guidotti CV; Malferrari D; Sassi FP ( 2008 ) - Single-crystal X-ray studies of trioctahedral micas coexisting with dioctahedral micas in metamorphic sequences from Western Maine - AMERICAN MINERALOGIST - n. volume 93 - pp. da 735 a 745 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

A crystal chemical study of thirteen biotite (twelve of 1M polytype and one of 2M1 polytype) and four muscovite samples were made. The biotite, coexists with the muscovite. Samples are from metamorphic terrains and from granitic and granodioritic bodies occurring in three areas of western Maine. The metamorphic mineral zones identified by mineral compatibilities are, for increasing metamorphic grade, the Lower Sillimanite Zone (LSZ), the Upper Sillimanite Zone (USZ) and the K-feldspar + Sillimanite Zone (K+SZ). The muscovite composition clusters near ideal muscovite and displays a small celadonite substitution and a small, but variable paragonite substitution. The biotite composition displays a ratio [vi]Mg2+ / [vi](Mg2+ + Fe2+) ranging from 0.26 to 0.54 and significant octahedral Al content from 0.48 to 0.72 apfu in metamorphic biotite samples and from 0.51 to 0.67 in those from granites).In trioctahedral micas from western Maine and especially in those with graphite, there is a greater number of interlayer vacancies than in common micas. Interlayer vacancies have an increase in interlayer cation – basal oxygen atom distances and a decrease in tetrahedral flattening angle tau, thus suggesting a reduced interlayer charge. With a few exceptions, tetrahedral rotation angle alpha is related to crystallization temperature. In particular alpha decreases with a temperature increase, and alpha is also related to octahedral chemical substitutions. Results tentatively suggest, for micas from metamorphic environments, a direct influence of genetic parameters (T and fO2) on mica crystal structure, and not just chemical composition.

M. BRIGATTI; MOTTANA A; MALFERRARI D; CIBIN G ( 2007 ) - Crystal structure and chemical composition of Li-, Fe-, and Mn-rich micas - AMERICAN MINERALOGIST - n. volume 92 - pp. da 1395 a 1400 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

We present in this paper the crystal chemical characterization of three (Fe, Mn)-rich lithian trioctahedral micas. The samples are from Hirukawa mine (Japan) (unit formula: [iv](Si3.425Al0.575)4.00[vi](Al1.002Ti0.002Cr0.001Fe0.379Mg0.005Mn0.173Li1.438)3.00 [xii](Ca0.002Ba0.001Na0.049K0.948Rb0.002)1.00 O10F2 ; unit-cell dimensions: a = 5.264(1), b = 9.086(2), c = 10.099(3) Å, β = 100.719(5)°, V = 474.6(2) Å3); from Mokrusha mine (Russia) (unit formula: [iv](Si3.304Al0.696)4.00 [vi](Al1.004Ti0.001Fe0.362Mg0.005 Mn0.306Li1.322)3.00 [xii](Ca0.012Ba0.001Na0.042K0.940Rb0.005)1.00 O10F2; unit-cell dimensions: a = 5.297(5), b = 9.133(7), c = 10.168(9) Å, β = 100.78(2)°, V = 483.2(7) Å3); and from Sawtooth Mountains (Boise County, Idaho, U.S.A.) (unit formula: [iv](Si3.105Al0.895)4.00 [vi](Al0.913Ti0.018 Fe0.456Mg0.031 Mn0.521Li1.061)3.00 [xii](Ca0.004Ba0.003Na0.048K0.924Rb0.021)1.00 O10F2; unit-cell dimensions a = 5.2984(3), b = 9.1461(6), c = 10.0966(7) Å, β = 100.818(4)°, V = 480.58(5) Å3). All crystals belong to 1M polytype with layer symmetry C12(1) and show M1 and M3 sites much greater than M2. Moreover mean electron count values are much more variable for M1 and M3 sites than for M2. Unlike sample from Sawtooth Mountains, tetrahedral mean bond lengths appear to be smaller for T1 than for T11 site in Hirukawa mine and in Mokrusha mine.When compared to samples from the zinnwaldite series, crystals under study show similar crystal chemical trends, thus hinting to similar effects produced on layer structure by Fe and Mn cations.

Valdre G; Malferrari D; Marchetti D; Brigatti MF ( 2007 ) - The effect of different plasma gas environments on vermiculite layer - APPLIED CLAY SCIENCE - n. volume 35 - pp. da 76 a 84 ISSN: 0169-1317 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work presents the first results of a broader research project aimed at the development or modifications of clays with increased properties for technological purposes and novel applications. This first step addresses on the chemical and physical properties of vermiculite treated with several ionised gasses in controlled plasma environments. Vermiculite is a 2:1 layered silicate with well-known chemical-exchange and surface properties useful in many industrial applications. The improving of these properties, in particular at the nanoscale level, can in principle enhance its application in known technological fields and extend its use in novel research and applicative areas as well as in nanotechnology. Vermiculite was treated with argon, air, water vapour and hydrogen radio frequency plasmas at room temperature for few minutes. As a general rule, plasma gasses induced various layer modifications. Chemical analyses evidenced a significant decrease in the interlayer cation content, especially for hydrogen and water vapour treated specimens. X-ray diffraction showed both a decrease of peak intensity and a halving of (001) reflection, thus suggesting the formation of layer defects along the layer stacking direction and onto (001) planes as well. Thermal analysis showed modifications of the temperature-activated reactions induced by the plasma treatments. Finally Fourier Transformed Infra-Red spectroscopy (FTIR) showed that different bonding of H2O occurred after the treatment, in particular for vermiculite treated with hydrogen plasma. (c) 2006 Elsevier B.V. All rights reserved.

Laurora A.; Brigatti MF.; Mottana A.; Malferrari D.; Caprilli E. ( 2007 ) - Crystal chemistry of trioctahedral micas in alkaline and subalkaline volcanic rocks: A case study from Mt. Sassetto (Tolfa district, Latium, central Italy) - AMERICAN MINERALOGIST - n. volume 92 - pp. da 468 a 480 ISSN: 0003-004X [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work provides a crystal-chemical description of trioctahedral micas from volcanic rocks (lavas, tuffs, ignimbrites, and xenoliths) outcropping at Mt. Sassetto (Tolfa district, Tuscan Province, central Italy). Mica crystals vary in composition from ferroan phlogopite to magnesian annite. Heterovalent octahedral substitutions are mainly related to Al3+, Ti4+, and, only in a few samples, to Fe3+. The two main mechanisms regulating Ti inlet into the mica structure are the Ti-oxy [Ti-VI(4+VI)(Mg,Fe)(-1)(2+)(OH)(-2)O--(2)2-] and Ti-vacancy [Ti-VI(4+VI)rectangle(VI)(Mg,Fe)(-2)(2+)] substitutions. In these micas, Ti content is the predominant crystal-chemical parameter and significantly affects octahedral and interlayer topology as well. Micas with the highest Ti contents deviate from the expected fractional crystallization trend in the Ti vs. Mg/(Mg + Fe-tot) diagram, possibly as a consequence of a variation in intensive parameters (T, P, f(H2),f(O2),f(H2O)) during crystallization in the magmatic chamber. In micas with significant Fe3+ contents, the layer charge balance is accomplished by the following mechanisms: (Fe-32+VIFe23+VI)-Fe-VI rectangle, (Fe-12+VIFe3+)-Fe-VI(OH)(-)O--(2-), and (Fe-12+VIFe3+IVSi-14+IVAl3+)-Fe-Vi. These micas show mean electron counts greater for the octahedral M2 site than for M1, and unit-cell parameters significantly smaller than usual for other micas. Atmospheric weathering is unlikely to produce the observed Fe oxidation. The Fe3+-vacancy and Fe-oxy substitutions could represent secondary, re-equilibration effects related to post-eruptive water-rock hydrothermal processes (acid-sulfate alteration).

M. BRIGATTI; GALLI E; MALFERRARI D; ROSSI A ( 2007 ) - Valutazione dello stato ambientale delle ex aree minerarie a solfuri di Boccassuolo (Palagano, Modena) e Cà Marsilio e Cà Gabriele (Montecreto, Modena) - SOTTO TERRA - n. volume 125 - pp. da 1 a 16 ISSN: - [Articolo in rivista (262) - Articolo su rivista]
Abstract

Negli ultimi decenni l'ambiente ipogeo artificiale ha attirato l'attenzione di numerosi speleologi e di studiosi che, attraverso ricerche a carattere multidisciplinare, hanno evidenziato non solo il particolare significato storico, religioso e culturale di tali siti, ma anche la loro importanza quali strutture attraverso le quali, ad esempio, è awenuto il rifornimento idrico di grandi città e come opere realizzate dall'uomo anche in tempi recenti per coltivare giacimenti di materie prime utili alla sua quotidianità. In quest'ultimo caso si tratta delle numerose gallerie di miniera quasi tutte ormai abbandonate, ma che in parte, se almeno recuperate e rese sicure ed agibili, possono rappresentare una non trascurabile attrazione turistica e locale fonte di lavoro. Per alcune di queste realtà talora è sorta la preoccupazione della possibilità che le acque da esse derivate o le loroaree di discarica esterne rappresentassero agenti di potenziali inquinanti di territori (ambienti) circostantida parte di elementi tossici (pericolosi) presenti nelle mineralizzazioni coltivate.In relazione a questo problema, in questa nota vengono presentati i risultati di analisi relative adalcuni possibili agenti inquinanti naturali, effettuate su campioni di terreni e vegetali, raccolti nell'intornodelle due uniche zone minerarie a solfuri della provincia di Modena. In particolare è statavalutata la concentrazione di metalli pesanti (Cu, Zn e Pb) in sedimenti e licheni campionati nell'areacircostante il complesso minerario. È stata inoltre valutata la speciazione chimica di questi elementi combinando differenti tecniche analitiche. I risultati ottenuti indicano che l'inquinamentodella zona non raggiunge valori significativamente pericolosi e che gli attuali livelli sono comparabilia quelli determinati dalla stessa presenza del complesso minerario (inquinamento naturale)

Brigatti MF; Caprilli E; Malferrari D; Mottana A ( 2007 ) - Crystal structure and crystal chemistry of fluorannite and its relationships to annite - MINERALOGICAL MAGAZINE - n. volume 71-6 - pp. da 683 a 690 ISSN: 0026-461X [Articolo in rivista (262) - Articolo su rivista]
Abstract

This contribution deals about the crystal chemical characterization of fluorannite from Katugin Ta-Nb deposit, Chitinskaya Oblast’, Kalar Range, Transbaikalia, Eastern-Siberian Region, Russia. The mineral chemical formula is (K0.960Na0.020Ba0.001) (Fe2+2.102Fe3+0.425Cr3+0.002Mg0.039Li0.085Ti0.210Mn0.057) (Al0.674 Si3.326) O10 (F1.060OH0.028O0.912). This mica belongs to 1M polytype (space group C2/m) with layer parameters a = 5.3454(2) Å, b = 9.2607(4) Å, c = 10.2040(5) Å, beta = 100.169(3)°. Structure refinement, using anisotropic displacement parameters, converged at R = 0.0384. When compared to annite, fluorannite shows a smaller cell volume (Vfluorannite = 497.19 Å3; Vannite = 505.71 Å3), because of its smaller lateral dimensions and its reduced c parameter. The flattening of the tetrahedral basal oxygen atoms plane decreases with F content, together with the A-O4 distance (i.e., the distance between interlayer A cation and the octahedral anionic position) because of the reduced repulsion between the interlayer cation and the anion sited in O4.

Brigatti M.F.; Malferrari D.; Poppi M.; Mottana A.; Cibin G.; Marcelli A.; Cinque G. ( 2007 ) - Interlayer potassium and its surrounding in micas: Crystal chemical modeling and XANES spectroscopy ( European Geosciences Union 2007 - - 15 - 20 April) ( - Geophysical Research Abstracts ) - GEOPHYSICAL RESEARCH ABSTRACTS - n. volume 9 - pp. da 02410 a 02410 ISSN: 1607-7962 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

Crystal chemistry and topology of the interlayer cations in micas were detailed by several authors and readily appeared not only to be sensitive to the interlayer composition, but to mirror also the topology of other sites occurring in the mica structure (i.e., tetrahedral, octahedral and anionic sites). The aim of this work is to provide a detailed description of the interlayer site in trioctahedral true micas by combining crystal-chemical and spectroscopic evidence. Insights obtained are based on a statistical appraisal of crystal-chemical, structural and spectroscopic data determined on two sets of trioctahedral micas extensively studied by both X-ray diffraction refinement on single crystals (SC-XRD) and X-ray absorption fine spectroscopy (XAFS) at the potassium K-edge. Spectroscopy was carried out on both random powders and oriented cleavage flakes, the latter setting taking advantage of the polarized character of synchrotron radiation. Such an approach (AXANES) is shown to be complementary to crystal-chemical investigation based on SC-XRD refinement. However, the results are not definitive as they focus on few samples having extreme features only (e.g., end-members, unusual compositions, and samples with extreme and well identified substitution mechanisms). The experimental absorption K-edge (XANES) was decomposed by calculation and extrapolated into a full in-plane absorption component (||) and a full out-of-plane absorption component (?). These two patterns reflect different structural features: || represents the arrangement of the atoms located in the mica interlayer space and facing tetrahedral sheets; ? is associated to multiplescattering interactions entering deep into the mica structure, thus reflecting also interactions with the heavy atoms (essentially Fe) located in the octahedral sheet. The out-of-plane pattern also reflects somewhat the octahedral atoms electronic properties, such as their oxidation states (e.g., Fe2+ and Fe3+) and their ordering (e.g., trans- vs. cis-setting). Distinction between fluoro- and hydrous micas is also possible due to peculiar absorption features originating from the F vs. OH occupancy of the O4 octahedral site. Thus, combining structural and spectroscopic information is shown to be a practical method that allows, on one hand, assigning the observed spectroscopic features to precise structural pathways followed by the photoelectron within the mica structure and, on the other hand, clarifying on the amount of electronic interactions and forces acting onto the individual atoms at the various structural sites.

Brigatti M.F.; Malferrari D.; Poppi M.; Mottana A.; Cibin G.; Marcelli A.; Cinque G. ( 2007 ) - Crystal chemical modeling and XANES spectroscopy of the potassium interlayer in micas ( 6th European Conference on Mineral Spectroscopy (ECMS 6) - - September 8-11, 2007) ( - Book of Abstract ) (- - ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Malferrari D.; Borghi V.; Brigatti M.F.; Laurora A.; Mantovani E.; Pistoni R. ( 2007 ) - Sedimenti provenienti dai canali di bonifica: valutazione del potenziale impatto ambientale. ( La crisi dei sistemi idrici: Approvvigionamento agro-industriale e civile - - 22 marzo 2007) ( - La crisi dei sistemi idrici: Approvvigionamento agro-industriale e civile ) (Accademia Nazionale dei Lincei Roma ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Malferrari D.; Brigatti M.F.; Laurora A.; Pini S.; Pistoni R. ( 2007 ) - Pollution of recent sediments from canals for water supplying and drainage ( Euroclay 2007 - - 22-27 luglio 2007) ( - Book of Abstract ) (AIPEA - ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Malferrari D.; Brigatti M.F.; Laurora A.; Pini S.; Pistoni R. ( 2007 ) - Polluted sediments from canals for water supplying and drainege: treatment and recycle ( Geoitalia 2007 - - 12-14 settembre) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 2 - pp. da 434 a 434 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

One of the most critical aspects of the maintenance of canals for water supplying and drainage is the managing of deposited sediments, which must be periodically removed. Deposited sediments, if containing anthropogenic pollutants with a concentration exceeding specific law limits, must be stored as industrial wastes, thus raising additional economic and logistic problems to deal with. Our research considers polluted sediments from an area close to the south side of Po river, in order to characterize heavy metals associated with different mineral species, thus defining effective treatments for their inertization, and suggesting a possible process for their recycle. Our results demonstrate that the composition of these sediments is suitable for the production of tiles and bricks. Several tests were thus performed to optimize sample treatment and other process parameters, finally giving very encouraging results. Releasing tests on fired products reveal that all the heavy metals are well retained.

Malferrari D.; Brigatti M.F.; Poppi M.; Mottana A.; Cibin G.; Marcelli A.; Cinque G. ( 2007 ) - Crystal chemical modeling and XANES spectroscopy of K in interlayer site of micas ( Geoitalia 2007 - - 12-14 settembre) ( - Epitome ) (FIST Udine ITA ) - EPITOME - n. volume 2 - pp. da 434 a 434 ISSN: 1972-1552 [Abstract in rivista (266) - Abstract in Rivista]
Abstract

A detailed description of the interlayer site in trioctahedral true micas is presented based on a statistical appraisal of crystal-chemical, structural, and spectroscopic data determined on two sets of trioctahedral micas extensively studied by both X-ray diffraction refinement on single crystals (SC-XRD) and X-ray absorption fine spectroscopy (XAFS) at the potassium K-edge. Spectroscopy was carried out on both random powders and oriented cleavage flakes, the latter setting taking advantage of the polarized character of synchrotron radiation. Such an approach (AXANES) is shown to be complementary to crystal-chemical investigation based on SC-XRD refinement. However, the results are not definitive as they focus on few samples having extreme features only (e.g., end-members, unusual compositions, and samples with extreme and well-identified substitution mechanisms). The experimental absorption K-edge (XANES) for potassium was decomposed by calculation and extrapolated into a full in-plane absorption component (sigma (sub ) ) and a full out-of-plane absorption component (sigma ). These two patterns reflect different structural features: sigma (sub ) represents the arrangement of the atoms located in the mica interlayer space and facing tetrahedral sheets; sigma is associated with multiple-scattering interactions entering deep into the mica structure, thus also reflecting interactions with the heavy atoms (essentially Fe) located in the octahedral sheet. The out-of-plane patterns also provide insights into the electronic properties of the octahedral cations, such as their oxidation states (e.g., Fe (super 2+) and Fe (super 3+) ) and their ordering (e.g., trans- vs. cis-setting). It is also possible to distinguish between F- and OH-rich micas due to peculiar absorption features originating from the F vs. OH occupancy of the O4 octahedral site. Thus, combining crystal-chemical, structural, and spectroscopic information is shown to be a practical method that allows, on one hand, assignment of the observed spectroscopic features to precise structural pathways followed by the photoelectron within the mica structure and, on the other hand, clarification of the amount of electronic interactions and forces acting onto the individual atoms at the various structural sites.

Pistoni R.; Malferrari D.; Brigatti M.F.; Pini S.; Tonelli F. ( 2007 ) - Recupero e valorizzazione di sedimenti estratti da canali di bonifica ed approvvigionamento idrico mediante inertizzazione termica. ( La crisi dei sistemi idrici: Approvvigionamento agro-industriale e civile. - - 22 marzo 2007) ( - La crisi dei sistemi idrici: Approvvigionamento agro-industriale e civile. ) (Accademia Nazionale dei Lincei Roma ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

M.F. BRIGATTI; E. GALLI; A. ROSSI; A. TOMBESI; G. VALDRE; D. MALFERRARI; A. LAURORA ( 2006 ) - Le miche: ordinamento cationico, popolazione anionica e loro controllo da parte dei fattori petrologici. [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Brigatti M.F.; Cibin G.; Cinque G.; Malferrari D.; Marcelli A.; Mottana A.; Pini S.; Poppi M. ( 2006 ) - Interlayer material and its surrounding in micas: crystal chemical modeling and XANES spectroscopy ( XXXV Congresso Nazionale A.I.C. - - 18-21 settembre 2006) ( - Book of Abstract ) (Associazione Italiana di Cristallografia Ferrara ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Malferrari D.; Brigatti M.F.; Cibin G.; Liu W.H.; Marcelli A.; Wu Z.Y. ( 2006 ) - Structure of Hg complexes in layer silicates: XAS and XRDP high temperature investigation ( XXXV Congresso Nazionale A.I.C. - - 18-21 settembre 2006) ( - Book of Abstract ) (Associazione Italiana di Cristallografia Ferrara ITA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Brigatti M. F.; Guidotti C.V.; Malferrari D.; Sassi F.P. ( 2006 ) - Crystal chemistry of some trioctahedral and dioctahedral micas coexisting in metamorphic sequences from N.W. Maine ( GSA Annual Meeting and Exposition, - - 22-25 Ottobre 2006) ( - Book of Abstract ) (GSA - USA ) [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Brigatti M.F; Malferrari D.; Poppi M.; Poppi L. ( 2005 ) - The 2M1 dioctahedral mica polytype: a crystal chemical study - CLAYS AND CLAY MINERALS - n. volume 53 - pp. da 190 a 197 ISSN: 0009-8604 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The structure of dioctahedral true micas such as muscovite and celadonitic muscovite (2M1 polytype, Space Group C2/c) is mostly affected by variations of the octahedral Al content ([vi]Al). Crystals with greater Mg, Fe substitutions (i.e., celadonitic muscovite) reduce the dimensional difference between the larger trans-oriented M(1) site and smaller cis-oriented M(2) octahedral site. The octahedral anionic position O(4) is displaced from the center of the hexagon, defined by O(31) and O(32) oxygen atoms (i.e., “octahedral hexagon”), both on and off the (001) plane. The distance between interlayer cation A and O(4) is smaller in more substituted species, thus providing different orientations of the O(4)-H vector, as a function of [vi]Al. Octahedral distances and are expressed as a function of cell parameters and [vi]Al content, thus allowing an approximate estimate of site dimensions. These approximations are useful when a detailed structural refinement is not available. In celadonitic muscovite, the octahedral hexagon mean edge is not significantly affected by [vi]Al content. The [vi]Al increase produces both a decrease in cell lateral dimensions and a distorted “octahedral hexagon”. The decrease in a and b is consistent with a decrease of , whereas the distortion of the “octahedral hexagon” is consistent with an increase of , because an irregular hexagon produces a longer mean edge than a regular hexagon of equal area.The tetrahedral mean basal edge is reduced as celadonitic substitution progresses. The tetrahedral rotation angle was thus found to increase from celadonite to muscovite. However in muscovite with [vi]Al content between 1.8 and 2.0 atoms per formula unit (apfu), approaches a saturation value, thus showing a proportional increase of tetrahedral and octahedral sheet lateral dimensions. Furthermore, alpha variation allows a coarse approximation of the threshold [vi]Al content, below which celadonitic substitution may not progress.

M.F. Brigatti; A. Laurora; D. Malferrari; L. Medici; L. Poppi ( 2005 ) - Adsorption of [Al(Urea)(6)](3+) and [Cr(Urea)(6)](3+) complexes in the vermiculite interlayer - APPLIED CLAY SCIENCE - n. volume 30 - pp. da 21 a 32 ISSN: 0169-1317 [Articolo in rivista (262) - Articolo su rivista]
Abstract

This work investigates the interaction between vermiculite and urea metal complexes {[Cr(Urea)(6)](3+) and [AI(Urea)(6)](3+)} via several techniques, including: i) chemical analyses; ii) X-ray diffraction at controlled temperature; iii) microdiffraction on selected crystal areas; iv) thermal analyses and mass spectrometry of evolved species during heating; v) atomic force microscopy; vi) micro-FTIR. Organo-clay complexes were prepared both at room (25 C) and 60 degrees C temperature. Vermiculite treated with [Al(Urea)(6)](3+) showed a complete adsorption of the complex at room temperature, unlike vermiculite treated with [Cr(Urea)(6)](3+) where only a partial exchange was observed. The X-ray investigation evidenced disordered sequences in the layer stacking as common in vermiculite treated with [Al(Urea)6](3+) and [Cr(Urea)(6)](3+) at 60 degrees C. Stacking disorder is present also at room temperature when complexed with [Cr(Urea)(6)](3+) solutions. Microdiffraction investigation identified several domains in vermiculite treated at 60 degrees C. This evidence is also reinforced by FTIR spectroscopy data, which revealed the presence of ammonium isocyanate.

Brigatti M.F.; Colonna S.; Malferrari D.; Medici L.; Poppi L. ( 2005 ) - Mercury adsorption by montmorillonite and vermiculite: a combined XRD, TG-MS, and EXAFS study. - APPLIED CLAY SCIENCE - n. volume 28 - pp. da 1 a 8 ISSN: 0169-1317 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Synchrotron based extended X-ray absorption fine structure spectroscopy (EXAFS), X-ray diffraction at room and high temperature, thermal analyses combined with mass spectrometry of evolved gas, and chemical analyses contributed to assess the influence of mercury on montmorillonite and vermiculite layers. The adsorbed Hg amount was higher for montmorillonite (Hg = 37.7 meq/100g) than for vermiculite (Hg = 28.0 meq/100g). The basal spacing for the Hg treated samples was 15.2 (montmorillonite) and 14.5 Å (vermiculite). Thermal and evolved gas spectrometry analyses suggest that Hg was released at T  230°C and at 600°C for montmorillonite, but at 550, 800 and 860°C for vermiculite. The effect of temperature on Hg release is also apparent when the basal spacing at 230°C for montmorillonite (d001 = 10.3 Å) is compared to that for vermiculite (d001 = 11.8 Å).EXAFS analyses provide qualitative evidence that oxygen atoms occupy the first coordination shell of Hg in both clay minerals. The best fit between observed and calculated spectra is obtained when montroydite is assumed as a reference model compound

Brigatti M.F.; Malferrari D.; Medici L.; Ottolini L.; Poppi L. ( 2004 ) - Crystal Chemistry of Apatites from the Tapira carbonatite complex, Brazil - EUROPEAN JOURNAL OF MINERALOGY - n. volume 16 - pp. da 677 a 685 ISSN: 0935-1221 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The crystal chemistry of ten hydroxyl fluorapatite crystals from the Tapira alkaline carbonatitic complex (Brazil) was investigated by electron microprobe, ion microprobe, infrared spectroscopy and single crystal X-ray diffraction. Apatite crystals are characterized by modest REE and a very low Cl content. They exhibit the following compositional range in atoms per formula unit was determined to be 9.935  Ca  10.024, 5.926  P  6.006, 0.005  REE  0.046, 0.422  F  0.914, 0.003  Cl  0.008, 0.003  Si  0.038; Na is present in trace.Crystal structure refinements were carried out in space group P63/m, (R values varies between 0.016 and 0.028). The REE for Ca substitution requires two different exchange mechanisms producing an increase in the bond valence on the X anionic site: the deprotonation of OH and/or the substitution of for OH. The substitution in the anionic sites of investigated structures was related to great CO2 activity of the melt whereas deprotonation of the apatite crystals could be related to the highly oxidizing nature of the Tapira carbonatitic magma. The very low Cl/F ratio suggests that the crystallization of Tapira pluton was relatively shallow. The determination of REE partitioning between the Ca1 and Ca2 sites is difficult because of the low REE content. A proportional increase in the size of the Ca1 and Ca2 sites was observed with increasing REE content as well as an overall increase of a parameter

M. BRIGATTI; MALFERRARI D.; MEDICI L.; POPPI L. ( 2004 ) - “Cu, Cd, Hg and Cu-, Cd-, Hg-cysteine treated montmorillonite and vermiculite crystals: an EXAFS study. ( XII Convegno SILS - - 5-8 luglio 2004) ( - Book of Abstract ) (Società Italiana Luce di Sincrotrone - ITA ) - pp. da 18 a 19 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

M.F. Brigatti; D. Malferrari; A. Laurora ( 2004 ) - Controllo dei fattori petrologici sulla cristallochimica delle miche. [Altro (298) - Partecipazione a progetti di ricerca]
Abstract

Malferrari D. ( 2003 ) - Organo-Metallic Complexes and Phyllosilicate - PLINIUS - n. volume 29 - pp. da 47 a 52 ISSN: 1120-317X [Articolo in rivista (262) - Articolo su rivista]
Abstract

The interaction between Cu exchanged smectites with different layer charge minerals and alpha amino acids glycine and cysteine were studied. A wide variety of analytical techniques were employed namely chemical analyses on solution and mineral, X ray diffraction at room temperature and in the temperature range between 25 and 400 °C, thermal analyses and evolved gasses mass spectrometry.The results suggest that: i) the amount of metal sorbed depends on pH and concentration of solution; ii) organo-metallic complexes are formed in the interalyer region and variations in the Cu local environment occur following treatments with amino acid solution.

Brigatti M.F.; Malferrari D.; Medici L.; Poppi L. ( 2003 ) - Structural and chemical modification induced in rectorite treated with Hg(II), Cd(II) and cysteine ( "Euroclay2003” - - June 22-26) ( - Book of Abstract ) (Clay Mineral Society Chantilly, Virginia USA ) - pp. da 46 a 46 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

M. BRIGATTI; MALFERRARI D.; MEDICI L.; POPPI L. ( 2003 ) - An EXAFS study on smectites exchanged with organo-metallic complexes ( Euroclay 2003 - - June 22-26) ( - Book of Abstract ) (Clay Mineral Society Chantilly, Virginia USA ) - pp. da 45 a 46 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

M. BRIGATTI; MALFERRARI D.; MEDICI L.; POPPI L. ( 2003 ) - Hg - cysteine complex sorbed by smectites - a combined XRD, TG-MS, and EXAFS study ( "Euroclay2003" - - June 22-26) ( - Book of Abstract ) (Clay Mineral Society Chantilly, Virginia USA ) - pp. da 45 a 45 ISBN: 0000000000 ISSN: - [Contributo in Atti di convegno (273) - Relazione in Atti di Convegno]
Abstract

nd

Brigatti M.F.; Malferrari D.; Medici L.; Poppi L. ( 2003 ) - Effect of amino acids on the retention of copper by beidellite - ENVIRONMENTAL ENGINEERING SCIENCE - n. volume 20(6) - pp. da 601 a 606 ISSN: 1092-8758 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The evaluation of environmental hazards related to Cu in urban and industrial run-off, as well as the introduction of possible technologies for the remediation of environmentally compromised areas should not be dealt independently form a sound understanding of structural features of the different interacting species. Low cost clay-minerals are potentially very promising materials for effectively exchanging and stoking Cu. A low cost beidellite was thus evaluated. The mineral behavior in accomplish its function is completely different for the natural and for amino acid complexed sample, with a major influence of the amino acid itself. Different experimental techniques were thus introduced: namely chemical, X-ray diffraction, thermal, mass spectrometry and X-ray absorption spectroscopy analyses. All the knowledge thus acquired on natural and treated species was thus finally related to their adsorption and retention capacity.

Brigatti M.F.; Benincasa E.; Malferrari D.; Medici L.; Poppi L. ( 2002 ) - Reactions of Zn2+ aqueous solutions with fluor-hydroxyapatite: a crystallographic evidence - NEUES JAHRBUCH FUR MINERALOGIE MONATSHEFTE - n. volume 3 - pp. da 129 a 137 ISSN: 0028-3649 [Articolo in rivista (262) - Articolo su rivista]
Abstract

In order to evaluate the possible use of natural fluor-hydroxyapatite (FOHAp) crystals as soil additive for the in situ remediation of heavy-metal contaminated soils, the crystal structure of FOHAp crystals, used in batch experiments at 22°C with pH within the range 4.8-9.5 and in presence of Zn2+ ions, was determined. Crystal structures (space group P63/m) converged to R = 0.026 for untreated FOHAp and to R =0.028 (Experiment 1) and R= 0.032 (Experiment 2) for Zn2+-treated FOHAp crystals. The site occupancy ratios [(Zn-Ca)2/(Zn-Ca)1] obtained from the refinement of electron density is = 1.500 for natural FOHAp, 1.500 (Experiment 1) and 1.520 (Experiment 2) in Zn2+-treated crystals. The value deriving from experiment 2 agrees with small changes in Ca2 site occupancy. Ca2O6X polyhedron distortions may be related both to a slight preference of Zn for Ca2 and to OH for F substitution during the overall reaction sequence.

Benincasa E.; Brigatti M.F.; Franchini G.; Malferrari D.; Medici L.; Poppi L.; Tonelli M. ( 2002 ) - Reactions between Cr(VI) solutions and pyrite: chemical and surface studies - GEOLOGICA CARPATHICA - n. volume 53 (2) - pp. da 1 a 7 ISSN: 1335-0552 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Geochemical processes that result in the reduction of hexavalent chromium in natural waters with pyrite (FeS2) have been studied at varying degrees of pH (from 1.2 to 12.6) and solution concentration (from 0.001 to 0.3 M of Cr6+) in order to illustrate the differences in the proportions of elements between the aqueous and solid phases and to infer mechanisms that limit the Cr6+ concentration in pore-waters in iron sulfide-rich environments. The experiments were carried out in the absence of oxygen and on pyrite grains previously treated to remove any oxide or sulfur layer at the mineral surface. The methods used to characterize reacting solutions and mineral surface comprised: chemical analyses (microprobe analyses and inductively coupled plasma analyses), scanning electron microscopy, atomic force microscopy and X-ray single crystal analysis. The results suggest that: 1) mineral dissolution increases with decreasing pH, whereas it is close to zero at pH > 7; at alkaline pH, the Cr6+ reduction is very low and the decrease in total Cr probably indicates the formation of precipitated phases, like FeCrO4, on the pyrite surface; 2) Cr6+ reduction is significant at pH < 2.3. Cr6+ to Cr3+ reduction involves the oxidation of Fe2+ and S22- on the pyrite surfaces, following the reaction 2FeS2+5Cr2O72-+32H+2Fe(OH)3 +4(SO4)2- +10Cr3+ +13H2O; 3) at acidic pH all the pyrite crystals show a variable Cr content on the surfaces.

Saccardo D.; Benincasa E.; Malferrari D.; Medici L. ( 2002 ) - I minerali di Monte Cengio - RIVISTA MINERALOGICA ITALIANA - n. volume 1 - pp. da 42 a 47 ISSN: 0391-9641 [Articolo in rivista (262) - Articolo su rivista]
Abstract

Sono descritti mineralicampionati in un filoncello a solfuri presso Monte Cengio (Vicenza) Le caratterizzazioni sono avvenute per via ottica e diffrattometrica. Tra i minerali riconosciuti sono presenti: adamite, anglesite, auricalcite, azzurrite, barite, beudanite, brochanite, calcite, cerussite, calcopirite, clinotirolite, cuprite, emimorfite, galena, idroncite, langite, malachite, mimetite, parnauite, pirite, quarzo, ramsbeckite, smithsonite sfalerite stolzite, tennantite, wulfenite.

E. Benincasa; M.F. Brigatti; D. Malferrari; L. Medici; L. Poppi ( 2002 ) - Sorption of Cd-cysteine complexes by kaolinite - APPLIED CLAY SCIENCE - n. volume 21 - pp. da 191 a 201 ISSN: 0169-1317 [Articolo in rivista (262) - Articolo su rivista]
Abstract

The effect of cysteine on the adsorption of Cd(II) by kaolinite was examined at 25 jC using a low-defect kaolinite fromMinas Gerais (Brazil) and a high-defect kaolinite from Berici Hills (Italy). The chemical data demonstrated that the amount ofCd–cysteine detected on kaolinite increases rapidly during the first few hours with a first-order reaction, thereafter adsorptionbecomes linear with time for low-defect kaolinite and slows rapidly for high-defect kaolinite. In low-ordered kaolinite, the Cd–cysteine is intercalated in the structure. Evidence of these changes was also observed by differential thermal analysis (DTA).The thermal decomposition of the Cd–cysteine adsorbed on the kaolinites was studied by analysing the evolved gases. Themass spectra of both samples show the evolution of NO (or CH3CH3, m/z = 30), CO2 (m/z = 44), and SO2 (m/z = 64) between 150 and 300 jC and of H2O (m/z = 18), CO2 (m/z = 44) and SO2 (m/z = 64) in the temperature range between 400 and 700 jC.The high-defect kaolinite also caused the evolution of molecular units with m/z=34 (H2S) and m/z=76 (N2O3). D 2002Elsevier Science B.V. All rights reserved.

Benincasa E.; Brigatti M.F.; Malferrari D.; Poppi L. ( 2000 ) - XAFS study of Cu sorption products on smectites treated with alpha-amino acids ( Proceedings of the International Congress on Applied Mineralogy - - 17-19 LUGLIO 2000) ( - Applied Mineralogy: In Research, Economy, Technology, Ecology and Culture, Proceedings of the International Congress on Applied Mineralogy ) (Rammlmair, Dieter Goettinge ) - n. volume 2 - pp. da 723 a 726 ISSN: - [Abstract in Atti di convegno (274) - Abstract in Atti di Convegno]
Abstract

The interaction between Cu-exchanged smectites with different layer charge, a montmorillonite and a beidellite, and .alpha.-amino acids, glycine and cysteine, was studied. Sequential extn. procedures were carried out in order to test the possibility of removing metals from the mineral structure. Cu sorption is dominated by cation exchange, whereas after the amino acid treatment, Cu-amino acid-smectite complexes occupy the interlayer positions. The formation of a stable chelate complex with .alpha.-amino acids permits Cu to be resistant to migration in soils and groundwaters. X-ray absorption spectroscopy was used to define the local environment of Cu taken up by smectites.