The oxidation of chalcopyrite, CuFeS, is still not well understood and relevant in the context of the hydrometallurgical extraction of copper. Herein, we used DFT calculations within the periodic boundary conditions formalism to study the adsorption of O and [Fe(HO)(OH)] molecules on the (001) and (112) surfaces of CuFeS. The O molecule adsorbs strongly by a dissociative pathway at sulfur atoms on the (001) surface with an adsorption energy of - 76.5 kcal mol. The surface is chemically modified forming SO groups, in which the S-O bond length is calculated to be 1.47 and 1.54 Å. PDOS and Löwdin charges analyses indicate the oxidation of the sulfur atoms on the surface. We tested different adsorption modes of [Fe(HO)(OH)], and a bidantade coordination with the O-Fe and Fe-S bond lengths of 2.02 and 2.47 Å is the most favorable with an adsorption energy of - 18.8 kcal mol on the (001) surface. Adsorptions of each species are also observed on the (112) surface, but they are weaker than those observed on the (001) surface.
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http://dx.doi.org/10.1007/s00894-022-05263-z | DOI Listing |
J Chem Phys
January 2025
Department of Chemistry, University of Washington, Seattle, Washington 98185, USA.
We derive a new expression for the strength of a hydrogen bond (VHB) in terms of the elongation of the covalent bond of the donor fragment participating in the hydrogen bond (ΔrHB) and the intermolecular coordinates R (separation between the heavy atoms) and θ (deviation of the hydrogen bond from linearity). The expression includes components describing the covalent D-H bond of the hydrogen bond donor via a Morse potential, the Pauli repulsion, and electrostatic interactions between the constituent fragments using a linear expansion of their dipole moment and a quadratic expansion of their polarizability tensor. We fitted the parameters of the model using ab initio electronic structure results for six hydrogen bonded dimers, namely, NH3-NH3, H2O-H2O, HF-HF, H2O-NH3, HF-H2O, and HF-NH3, and validated its performance for extended parts of their potential energy surfaces, resulting in a mean absolute error ranging from 0.
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January 2025
Hephaestus Laboratory, School of Chemistry, Faculty of Sciences, Democritus University of Thrace, GR-65404 Kavala, Greece.
The remediation of wastewaters contaminated with dyes (discharged mainly from industry) is very important for preserving environmental quality and human health. In this study, a new composite chitosan (CS)-based adsorbent combined with activated carbon (AC) and curcumin (Cur) (abbreviated hereafter as CS/AC@Cur) in three different ratios (12.5%, 25%, and 50%) was synthesized for the removal of anionic [reactive black 5 (RB5)] and cationic [methylene blue (MB)] dyes in single-component or binary systems.
View Article and Find Full Text PDFJ Appl Physiol (1985)
January 2025
Experimental Biomechanics Group, Institute of Structural Mechanics and Dynamics in Aerospace Engineering, Faculty of Aerospace Engineering and Geodesy, University of Stuttgart, Germany.
Characterizing individual muscle behavior is crucial for understanding joint function and adaptations to exercise, diseases, or aging. Shear wave elastography (SWE) is a promising tool for measuring the intrinsic material properties of muscle. This study assessed the passive and active shear modulus of the triceps surae muscle group in 14 volunteers (7 females, 25.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Materials Science and Engineering, Kyushu Institute of Technology, 1-1 Sensui-cho, Tobata-ku, Kitakyushu 804-8550, Japan.
Self-organization realizes various nanostructures to control material properties such as superconducting vortex pinning and thermal conductivity. However, the self-organization of nucleation and growth is constrained by the growth geometric symmetry. To realize highly controlled three-dimensional nanostructures by self-organization, nanostructure formation that breaks the growth geometric symmetry thermodynamically and kinetically, such as tilted or in-plane aligned nanostructures, is a challenging issue.
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January 2025
Department of Obstetrics and Gynecology, Seoul National University College of Medicine, Jongno-gu, Seoul, Korea.
Objective: Accurate measurement of pelvic floor muscle (PFM) strength is crucial for the management of pelvic floor disorders. However, the current methods are invasive, uncomfortable, and lack standardization. This study aimed to introduce a novel noninvasive approach for precise PFM strength quantification by leveraging extracorporeal surface perineal pressure (ESPP) measurements and machine learning algorithms.
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