Nanoscale cross-correlated AFM, Kelvin probe, elastic modulus and quantum mechanics investigation of clay mineral surfaces: The case of chlorite

Moro, Daniele; Ulian, Gianfranco; Valdrè, Giovanni

doi:10.1016/j.clay.2015.11.023

Cited by 33 publications

(28 citation statements)

References 35 publications

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“…Atomic force microscopy (AFM) is a well established methodology for the study of nanomorphologies and surface properties of layer silicates at the nanometer scale789. Recently, the AFM was used to investigate the in situ K + − Na + ion exchange in phlogopite single-crystals10.…”

Section: Resultsmentioning

confidence: 99%

“…Bruker NP type silicon nitride triangular probes with nominal force constant, k, between 0.06 N · m −1 and 0.58 N · m −1 and nominal tip radius of curvature 20 nm were used in contact mode. Furthermore, Kelvin probe mode9 was employed to investigate surface electrostatic potential variations by means of Nanoworld EFM type and Arrow-EFM type Pt-Ir coated silicon rectangular probes (Nanoworld AG, Neuchâtel, Switzerland). Both probes have nominal force constant, k, 2.8 N · m −1 , nominal resonant frequency 75 kHz and nominal tip radius of curvature 25 nm.…”

Section: Methodsmentioning

confidence: 99%

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Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging

Moro

Valdrè

Mesto

et al. 2017

Sci Rep

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This study presents a cross-correlated surface and near surface investigation of two phlogopite polytypes from Kasenyi kamafugitic rocks (SW Uganda) by means of advanced Atomic Force Microscopy (AFM), confocal microscopy and Raman micro-spectroscopy. AFM revealed comparable nanomorphology and electrostatic surface potential for the two mica polytypes. A widespread presence of nano-protrusions located on the mica flake surface was also observed, with an aspect ratio (maximum height/maximum width) from 0.01 to 0.09. Confocal microscopy showed these features to range from few nm to several μm in dimension, and shapes from perfectly circular to ellipsoidic and strongly elongated. Raman spectra collected across the bubbles showed an intense and convolute absorption in the range 3000–2800 cm−1, associated with weaker bands at 1655, 1438 and 1297 cm−1, indicating the presence of fluid inclusions consisting of aliphatic hydrocarbons, alkanes and cycloalkanes, with minor amounts of oxygenated compounds, such as carboxylic acids. High-resolution Raman images provided evidence that these hydrocarbons are confined within the bubbles. This work represents the first direct evidence that phlogopite, a common rock-forming mineral, may be a possible reservoir for hydrocarbons.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging

Moro

Valdrè

Mesto

et al. 2017

Sci Rep

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“…This reveals that the H ions preferentially attack the unsaturated O of Al-O tetrahedrons when the tetrahedral sheets are dissolving. A similar behavior is also observed for other trioctahedral phyllosilicates [29,30]. In order to distinguish the chemisorption or electrostatic adsorption of H ions on the surface of tetrahedral sheets, it is necessary to investigate the interaction between H and O un and particularly the influence on the neighboring Si and Al.…”

Section: Formation Of the 001 Surface Hydroxylmentioning

confidence: 99%

Removal Process of Structural Oxygen from Tetrahedrons in Muscovite during Acid Leaching of Vanadium-Bearing Shale

et al. 2018

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Process mineralogy shows that most vanadium in mica-type black shale exists in the octahedral sites of muscovite. The extraction of vanadium mainly occurs in the acid leaching process with participation of H ions. In this work, we firstly analyzed the dissolution rules of elements in acid leaching of muscovite, then adopted the density functional theory (DFT) calculation to accurately visualize the primary process of the surface corrosion of muscovite by H ions. The experimental results show that K releases the fastest and the release of Al is consistent with K. The simulation results find that the H preferentially shifts to the unsaturated structured O of the tetrahedron to form a strong 001 surface hydroxyl after replacing K, as well as relaxing the near Al(Si)-O bonds for the further removal of structural oxygen. Then, the 001 surface hydroxyls more likely participate in the dehydroxylation reaction through the reverse-path mechanism to remove the structural oxygen and break the hexagonal rings of the tetrahedral sheets. Remarkably, the formation and removal of structural water are overall endoergic, meaning that the disintegration of muscovite requires a sustained supply of heat. Further, the octahedral sheets where vanadium exists can be exposed to the acid environment for overall destruction. This detailed atomic migration process in acid leaching of black shale is visualized, which not only illuminates the reaction mechanism of H ions with the muscovite, but also provides guidance for vanadium extraction from black shale and a new concept for the destruction of other minerals.

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“…Since the advent of modern quantum chemistry, experimental methods and theoretical simulations have obtained beneficial contributions by cross‐correlations of each other, the firsts by reaching atomic‐level understanding of physico‐chemical phenomena observed at lager scales, the seconds by including methods to correctly describe the experimental results . Furthermore, the constant increase in computation powers allows simulating very complex system in reasonable time.…”

Section: Introductionmentioning

confidence: 99%

Second‐order elastic constants of hexagonal hydroxylapatite (P6₃) fromab initioquantum mechanics: Comparison between DFT functionals and basis sets

Ulian

Valdrè

2017

Int J of Quantum Chemistry

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Three very popular Hamiltonians in the density functional theory framework, PBE, PBEsol, and B3LYP, and different basis sets (Gaussian‐type orbitals and plane waves) were employed to simulate the hydroxylapatite unit cell and its second‐order elastic constants. Dispersive interactions were included in the quantum‐mechanical treatment via the DFT‐D2 and Tkatchenko‐Scheffler schemes. The calculated bulk, shear, and Young's moduli were in the range of 82‐117 GPa, 42‐51 GPa, and 107‐134 GPa, respectively. The axial moduli, Ka and Kb, were instead in the range of 277‐322 GPa and 506‐509 GPa. The theoretical data, especially those from plan waves simulations, are in good agreement with available results in literature and further extend the knowledge of the mechanical and vibrational properties of hydroxylapatite.

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Nanoscale cross-correlated AFM, Kelvin probe, elastic modulus and quantum mechanics investigation of clay mineral surfaces: The case of chlorite

Cited by 33 publications

References 35 publications

Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging

Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging

Removal Process of Structural Oxygen from Tetrahedrons in Muscovite during Acid Leaching of Vanadium-Bearing Shale

Second‐order elastic constants of hexagonal hydroxylapatite (P6₃) fromab initioquantum mechanics: Comparison between DFT functionals and basis sets

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Nanoscale cross-correlated AFM, Kelvin probe, elastic modulus and quantum mechanics investigation of clay mineral surfaces: The case of chlorite

Cited by 33 publications

References 35 publications

Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging

Hydrocarbons in phlogopite from Kasenyi kamafugitic rocks (SW Uganda): cross-correlated AFM, confocal microscopy and Raman imaging

Removal Process of Structural Oxygen from Tetrahedrons in Muscovite during Acid Leaching of Vanadium-Bearing Shale

Second‐order elastic constants of hexagonal hydroxylapatite (P63) fromab initioquantum mechanics: Comparison between DFT functionals and basis sets

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Product

Resources

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Second‐order elastic constants of hexagonal hydroxylapatite (P6₃) fromab initioquantum mechanics: Comparison between DFT functionals and basis sets