0000000000266754

AUTHOR

Francesco Princivalle

showing 7 related works from this author

High-pressure crystal structure investigation of synthetic Fe2SiO4 spinel.

2011

AbstractThe crystal structure of Fe2SiO4 spinel at room temperature was investigated at seven different pressures by X-ray diffraction, using a diamond anvil cell to examine the influence of Fe substitution on ringwoodite behaviour at high pressure. The results compared with those of a pure Mg endmember show that the substitution of Fe into the spinel structure causes only small changes in the compression rate of coordination polyhedra and the distortion of the octahedron. The data show that the compression rate for the octahedron and tetrahedron in (Mg,Fe)2SiO4 can be considered statistically equal for FeO6 and MgO6, as well as for SiO4 in both the endmembers. This shows why almost identic…

Materials sciencehigh pressure; X-ray diffraction; single crystal; synthetic Fe2SiO4 spinel010504 meteorology & atmospheric scienceshigh pressure X-ray diffraction single crystal synthetic Fe2SiO4 spinelX ray diffractionSpinel550 - Earth sciencesCrystal structureengineering.material01 natural scienceshigh pressure; X ray diffraction; single crystal; synthetic Fe2SiO4 spinelX-ray diffractionCrystallographyRingwooditehigh pressureOctahedronsynthetic Fe2SiO4 spinelGeochemistry and PetrologyX-ray crystallographyengineeringTetrahedronsingle crystalSingle crystal0105 earth and related environmental sciencesSolid solution
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Pressure stability field of Mg-perovskite under deep mantle conditions: A topological approach based on Bader's analysis coupled with catastrophe the…

2019

Abstract The pressure stability field of the Mg-perovskite phase was investigated by characterizing the evolution of the electron arrangement in the crystal. Ab initio calculations of the perovskite structures in the range 0–185 GPa were performed at the HF/DFT (Hartree-Fock/Density Functional Theory) exchange–correlation terms level. The electron densities, calculated throughout the ab-initio wave functions, were analysed by means of the Bader's theory, coupled with Thom's catastrophe theory. To the best of our knowledge the approach is used for the first time. The topological results show the occurrence of two topological anomalies at P~20 GPa and P~110 GPa which delineate the pressure ra…

Materials Chemistry2506 Metals and AlloysMaterials scienceBader analysisAb initioSurfaces Coatings and FilmCritical pointsCeramics and Composite02 engineering and technologyElectronD’’ regionPerovskiteTopology01 natural sciencesCritical pointPhysics::GeophysicsFock spaceCoatings and FilmsCondensed Matter::Materials ScienceAb initio quantum chemistry methods0103 physical sciencesElectronicMaterials ChemistryOptical and Magnetic MaterialsAb initio; Bader analysis; Catastrophe theory; Critical points; Deep mantle; D’’ region; HF/DFT; High pressure; Perovskite; Topological analysis; Electronic Optical and Magnetic Materials; Ceramics and Composites; Process Chemistry and Technology; Surfaces Coatings and Films; Materials Chemistry2506 Metals and AlloysWave function010302 applied physicsCatastrophe theoryElectronic Optical and Magnetic MaterialProcess Chemistry and TechnologyHartree021001 nanoscience & nanotechnologyHF/DFTSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsSurfacesTopological analysiHigh pressureAb initioCeramics and CompositesDensity functional theoryDeep mantleCatastrophe theory0210 nano-technologyTopological analysisBader analysiCeramics International
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Ordering kinetics in synthetic Mg(Al,Fe3+)2O4 spinels: Quantitative elucidation of the whole Al-Mg-Fe partitioning, rate constants, activation energi…

2014

A novel procedure, based on the application of the kinetics simulator Gepasi, has been successfully applied for modeling the cation ordering process in two synthetic Mg(Al2-yFe3+y)O4 spinels (y~ 0.39 and 0.54, samples F39 and F54, respectively). The kinetic profiles suggested a two-stage mechanism, with rapid inter-site exchange of Fe3+ with Mg followed by slow exchange of Al with Mg. The trial to apply the classical approaches, based on the explicit solutions of the differential equations corresponding to single-cation (Sha-Chappel model) or two-cation (Müller model) exchange reactions, proved not feasible in the whole time range, thus implying a lack of information about the exchange proc…

KineticSettore GEO/06 - MineralogiaspinelChemistryKineticsCationic polymerizationMineralogyActivation energyRate equationKinetic energyintersite cation exchangeKineticsGeophysicsReaction rate constantIntersite cation exchange spinels kinetics rate constant activation energy geothermometersactivation energyGeochemistry and PetrologyIron contentintersite cation exchange; spinels; Kinetics; activation energy; geothermometerPhysical chemistryspinelsgeothermometerTime rangeSettore CHIM/02 - Chimica Fisica
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Olive mill wastewaters decontamination based on organo-nano-clay composites

2019

Abstract Green composites for environmental applications were successfully prepared by intercalation of the biosurfactant Quillaja saponin onto montmorillonite mineral clay on varying pH and surfactant/clay ratio. Equilibrium adsorption isotherms were constructed and the system was characterized by performing TGA and XRD analyses. The efficiency of the surfactant-modified clay in the removal of the organic content present in olive mill wastewaters (OMW) was evaluated by means of spectrophotometric measurements. The interest for this cogent issue comes from the consideration that, despite their high pollutant content, OMW can be considered as a potential resource of several organic compounds…

PolyphenolMaterials Chemistry2506 Metals and AlloysMaterials scienceHill isothermXRDIntercalation (chemistry)Surfaces Coatings and FilmQuillaja saponinCeramics and Composite02 engineering and technology01 natural sciencesCoatings and Filmschemistry.chemical_compoundAdsorptionPulmonary surfactant0103 physical sciencesMaterials ChemistryElectronicOrganoclayOptical and Magnetic MaterialsComposite materialMontmorillonite010302 applied physicsOlive mill wastewaterAdsorption; Biowaste; Hill isotherm; Montmorillonite; Olive mill wastewaters; Polyphenols; Quillaja saponin; TGA; XRD; Electronic Optical and Magnetic Materials; Ceramics and Composites; Process Chemistry and Technology; Surfaces Coatings and Films; Materials Chemistry2506 Metals and AlloysTGAbiologyElectronic Optical and Magnetic MaterialProcess Chemistry and TechnologyPolyphenolsHuman decontaminationBiowaste021001 nanoscience & nanotechnologybiology.organism_classificationSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsSurfacesSubstrate (building)MontmorillonitechemistryQuillajaCeramics and CompositesOlive mill wastewatersAdsorption0210 nano-technology
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The pressure-induced ringwoodite to Mg-perovskite and periclase post-spinel phase transition: a Bader’s topological analysis of the ab initio electro…

2011

In order to characterize the pressure-induced decomposition of ringwoodite (c-Mg2SiO4), the topological analysis of the electron density q(r), based upon the theory of atoms in molecules (AIM) developed by Bader in the framework of the catastrophe theory, has been performed. Calculations have been carried out by means of the ab initio CRYSTAL09 code at the HF/DFT level, using Hamiltonians based on the Becke- LYP scheme containing hybrid Hartree– Fock/density functional exchange–correlation terms. The equation of state at 0 K has been constructed for the three phases involved in the post-spinel phase transition (ringwoodite -> Mg-perovskite + periclase) occurring at the transition zone–lower…

Bader’s topological analysisElectron densityEquation of statePhase transitionRingwoodite Post-spinel phase transition Bader’s topological analysis Ab initio Catastrophe theory Critical pointsChemistryCatastrophe theoryAtoms in moleculesRingwooditeAb initioCritical pointsHartreeengineering.materialTopologyRingwoodite; Post-spinel phase transition; Bader’s topological analysis; Ab initio; Catastrophe theory; Critical pointsPost-spinel phase transitionRingwooditeGeochemistry and PetrologyBader’s topological analysiAb initioengineeringGeneral Materials SciencePerovskite (structure)
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A Raman spectroscopy study of the oxidation processes in synthetic chromite FeCr2O4

2020

Abstract A crystal of synthetic chromite FeCr2O4 has been annealed in air at 700 °C for 50 days at room pressure in order to study physical-chemical changes. After the annealing treatment, Scanning Electron Microscopy (SEM) images of the polished surface of the sample showed areas of different composition. Detailed Raman mapping revealed that the annealed chromite undergoes an oxidation process, proceeding inwards from the outer surface and leading to the transformation of chromite to magnetite, and ultimately to hematite. The oxidation process also leads to the formation of trellis-like lines, arguably via stress-related mechanisms associated with the phase transformation and consequent vo…

Materials scienceRaman mappingAnnealing (metallurgy)Scanning electron microscopeSpinelHematite02 engineering and technologyRaman mapping01 natural sciencesMagnetitechemistry.chemical_compoundsymbols.namesake0103 physical sciencesOxidationMaterials ChemistryMagnetite010302 applied physicsProcess Chemistry and TechnologyChromiteHematite021001 nanoscience & nanotechnologySpinel; Chromite; Magnetite; Hematite; Oxidation; Raman mappingSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialschemistryChemical engineeringvisual_artCeramics and Compositessymbolsvisual_art.visual_art_mediumChromiteOxidation process0210 nano-technologyRaman spectroscopy
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Simultaneous Removal and Recovery of Metal Ions and Dyes from Wastewater through Montmorillonite Clay Mineral

2019

The main objective of this work was to evaluate the potential of Montmorillonite nanoclay (Mt), readily and inexpensively available, for the simultaneous adsorption (and removal) of two classes of pollutants: metal ions and dyes. The attention was focused on two &ldquo

DyeGeneral Chemical EngineeringMetal ions in aqueous solutionGroundwater remediation02 engineering and technologyAdsorption; Dyes; Metal ions; Montmorillonite; Wastewaters010501 environmental sciences01 natural sciencesdyesmetal ionArticlechemistry.chemical_compoundsymbols.namesakeAdsorptionGeneral Materials ScienceCrystal violetMetal ionwastewater0105 earth and related environmental sciencesSettore CHIM/02 - Chimica FisicaMontmorilloniteSettore GEO/06 - MineralogiaAqueous solutionLangmuir adsorption modelmetal ions021001 nanoscience & nanotechnologyWastewatersMontmorilloniteWastewaterChemical engineeringchemistryadsorptionsymbolsAdsorption0210 nano-technologywastewatersNanomaterials
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