Geochemical Kinetics via Computational Chemistry

Kubicki, James D.; Rosso, Kevin M.

doi:10.1002/9781118845226.ch11

Cited by 12 publications

(13 citation statements)

References 296 publications

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“…The specific molecular-level organization of water at aqueous interfaces is at the origin of many natural phenomena, ranging from biology and catalysis, − to pollutant transport in groundwater and mineral dissolution, , to atmospheric chemistry. − It is also of crucial importance in electrochemistry, phase-separation processes, and many other technological applications. , …”

Section: Dft-md To Characterize the 2d-hb-networkmentioning

confidence: 99%

Molecular Fingerprints of Hydrophobicity at Aqueous Interfaces from Theory and Vibrational Spectroscopies

Pezzotti

Serva

Sebastiani

et al. 2021

J. Phys. Chem. Lett.

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Hydrophobicity/hydrophilicity of aqueous interfaces at the molecular level results from a subtle balance in the water–water and water–surface interactions. This is characterized here via density functional theory–molecular dynamics (DFT-MD) coupled with vibrational sum frequency generation (SFG) and THz-IR absorption spectroscopies. We show that water at the interface with a series of weakly interacting materials is organized into a two-dimensional hydrogen-bonded network (2D-HB-network), which is also found above some macroscopically hydrophilic silica and alumina surfaces. These results are rationalized through a descriptor that measures the number of “vertical” and “horizontal” hydrogen bonds formed by interfacial water, quantifying the competition between water–surface and water–water interactions. The 2D-HB-network is directly revealed by THz-IR absorption spectroscopy, while the competition of water–water and water–surface interactions is quantified from SFG markers. The combination of SFG and THz-IR spectroscopies is thus found to be a compelling tool to characterize the finest details of molecular hydrophobicity at aqueous interfaces.

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Section: Dft-md To Characterize the 2d-hb-networkmentioning

confidence: 99%

Molecular Fingerprints of Hydrophobicity at Aqueous Interfaces from Theory and Vibrational Spectroscopies

Pezzotti

Serva

Sebastiani

et al. 2021

J. Phys. Chem. Lett.

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“…With the combination of the quantum chemical simulations of the outer-sphere ion pair formation and the second-shell X/H 2 O competition, we can investigate the effect of the type, configuration, and concentration of the ligand on the formation mechanisms of Al 3+ –X complexes. Ultimately, these findings would be of great significance in elucidating the ecotoxicological effects of Al 3+ and the mechanism of mineral surface complexation. − …”

Section: Resultsmentioning

confidence: 99%

Density Functional Theory Studies on the Real and Apparent Water-Exchange Reaction Kinetics of Al³⁺ in Aqueous Solution

Dong

Zhang

Yuan

et al. 2019

ACS Earth Space Chem.

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The dissociative (D) mechanistic water-exchange kinetics of aquated Al 3+ in aqueous solution is systematically studied using the density functional theory−quantum chemical cluster model (DFT−CM) method. The modeled pathways include dehydration of hexacoordinated Al(H 2 O) 6 3+ and successive hydration of pentacoordinated Al(H 2 O) 5 3+ . For the hydration of Al(H 2 O) 5 3+ , the attacking pathways corresponding to the second-shell solvent water molecules at different sites are investigated. The gas phase-supermolecule-polarizable continuum model (GP-SM-PCM) is used to simulate the explicit and bulk solvation effects. The reactant, transition state, and product geometries of the modeled reaction pathways are optimized at the B3LYP/6-311+G(d,p) level of theory. The real and apparent water-exchange reaction mechanisms of Al 3+ are analyzed on the basis of Gibbs free energy changes for the dehydration and hydration pathways. The possible ligand competition with the solvent water molecules in the formation of aqueous Al 3+ −ligand complexes is discussed, which provides a useful reference for further analysis of the molecular transformation mechanisms of Al species in the natural environment.

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“…AIMD method has proven to be powerful in quantifying the structural and thermodynamical properties of mineral-cation interactions (Alexandrov and Rosso, 2015;Kubicki, 2016;Leung et al, 2018;Liu et al, 2022). We determined the complexation structures and the associated free energy changes of Sc 3+ on montmorillonite (010) edge and made comparison with Y 3+ .Y 3+ is enriched in IADs in South China (Zhou et al, 2020) and here it is selected as an example of heavy REEs.…”

Section: Introductionmentioning

confidence: 99%

Understanding the unique geochemical behavior of Sc in the interaction with clay minerals

Zhang,

Liu,

et al. 2024

American Mineralogist

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Regolith-hosted rare earth elements (REEs) deposits received great attention due to the increasing incorporation of REEs in modern technologies. In lateritic Sc deposits and ion-adsorption deposits (IADs), Sc behaves quite differently from other REEs: REEs adsorb as outer-sphere complexes on clay surface in IADs while Sc could enter the lattice of clay minerals in lateritic Sc deposits. The unique behavior of Sc has not been well understood yet. Here, by using first-principles molecular dynamics techniques, we show that the complexation mechanisms of Y 3+ and Sc 3+ on clay edge surfaces are distinctly different. Y 3+ preferentially adsorbs on Al(OH) 2 SiO site with its coordination water protonated. Sc 3+ is found to behave similarly to other first-row transition metals (e.g. Ni 2+ ) due to its smaller ionic radius and prefers adsorbing on the vacancy site, from where Sc 3+ can be readily incorporated in the clay lattice. The H 2 O ligands of Sc 3+ get deprotonated upon complexation, providing new binding sites for further enrichment of Sc 3+ . These processes prevent Sc 3+ from being leached during weathering and lead to the formation of Sc-rich clay minerals found in lateritic deposits. Based on these results, it is revealed that the small ionic radius and high affinity to enter the vacancy on edge surfaces make Sc compatible with clay minerals and are the origin of its unique geochemical behavior.

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Geochemical Kinetics via Computational Chemistry

Cited by 12 publications

References 296 publications

Molecular Fingerprints of Hydrophobicity at Aqueous Interfaces from Theory and Vibrational Spectroscopies

Molecular Fingerprints of Hydrophobicity at Aqueous Interfaces from Theory and Vibrational Spectroscopies

Density Functional Theory Studies on the Real and Apparent Water-Exchange Reaction Kinetics of Al³⁺ in Aqueous Solution

Understanding the unique geochemical behavior of Sc in the interaction with clay minerals

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Geochemical Kinetics via Computational Chemistry

Cited by 12 publications

References 296 publications

Molecular Fingerprints of Hydrophobicity at Aqueous Interfaces from Theory and Vibrational Spectroscopies

Molecular Fingerprints of Hydrophobicity at Aqueous Interfaces from Theory and Vibrational Spectroscopies

Density Functional Theory Studies on the Real and Apparent Water-Exchange Reaction Kinetics of Al3+ in Aqueous Solution

Understanding the unique geochemical behavior of Sc in the interaction with clay minerals

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Product

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Density Functional Theory Studies on the Real and Apparent Water-Exchange Reaction Kinetics of Al³⁺ in Aqueous Solution