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Agosta L, Arismendi-Arrieta D, Dzugutov M, Hermansson K. Origin of the Hydrophobic Behaviour of Hydrophilic CeO 2. Angew Chem Int Ed Engl 2023; 62:e202303910. [PMID: 37011105 DOI: 10.1002/anie.202303910] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/02/2023] [Accepted: 04/03/2023] [Indexed: 04/05/2023]
Abstract
The nature of the hydrophobicity found in rare-earth oxides is intriguing. The CeO2 (100) surface, despite its strongly hydrophilic nature, exhibits hydrophobic behaviour when immersed in water. In order to understand this puzzling and counter-intuitive effect we performed a detailed analysis of the confined water structure and dynamics. We report here an ab-initio molecular dynamics simulation (AIMD) study which demonstrates that the first adsorbed water layer, in immediate contact with the hydroxylated CeO2 surface, generates a hydrophobic interface with respect to the rest of the liquid water. The hydrophobicity is manifested in several ways: a considerable diffusion enhancement of the confined liquid water as compared with bulk water at the same thermodynamic condition, a weak adhesion energy and few H-bonds above the hydrophobic water layer, which may also sustain a water droplet. These findings introduce a new concept in water/rare-earth oxide interfaces: hydrophobicity mediated by specific water patterns on a hydrophilic surface.
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Affiliation(s)
- Lorenzo Agosta
- Department of Chemistry-Ångström, Uppsala University, 751 21, Uppsala, Sweden
| | | | - Mikhail Dzugutov
- Department of Chemistry-Ångström, Uppsala University, 751 21, Uppsala, Sweden
| | - Kersti Hermansson
- Department of Chemistry-Ångström, Uppsala University, 751 21, Uppsala, Sweden
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2
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Alizadeh Sahraei A, Azizi D, Mokarizadeh AH, Boffito DC, Larachi F. Emerging Trends of Computational Chemistry and Molecular Modeling in Froth Flotation: A Review. ACS ENGINEERING AU 2023; 3:128-164. [PMID: 37362006 PMCID: PMC10288516 DOI: 10.1021/acsengineeringau.2c00053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 04/04/2023] [Accepted: 04/06/2023] [Indexed: 06/28/2023]
Abstract
Froth flotation is the most versatile process in mineral beneficiation, extensively used to concentrate a wide range of minerals. This process comprises mixtures of more or less liberated minerals, water, air, and various chemical reagents, involving a series of intermingled multiphase physical and chemical phenomena in the aqueous environment. Today's main challenge facing the froth flotation process is to gain atomic-level insights into the properties of its inherent phenomena governing the process performance. While it is often challenging to determine these phenomena via trial-and-error experimentations, molecular modeling approaches not only elicit a deeper understanding of froth flotation but can also assist experimental studies in saving time and budget. Thanks to the rapid development of computer science and advances in high-performance computing (HPC) infrastructures, theoretical/computational chemistry has now matured enough to successfully and gainfully apply to tackle the challenges of complex systems. In mineral processing, however, advanced applications of computational chemistry are increasingly gaining ground and demonstrating merit in addressing these challenges. Accordingly, this contribution aims to encourage mineral scientists, especially those interested in rational reagent design, to become familiarized with the necessary concepts of molecular modeling and to apply similar strategies when studying and tailoring properties at the molecular level. This review also strives to deliver the state-of-the-art integration and application of molecular modeling in froth flotation studies to assist either active researchers in this field to disclose new directions for future research or newcomers to the field to initiate innovative works.
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Affiliation(s)
- Abolfazl Alizadeh Sahraei
- Department
of Chemical Engineering, Université
Laval, 1065 Avenue de la Médecine, Québec, Québec G1V 0A6, Canada
| | - Dariush Azizi
- Department
of Chemical Engineering, École Polytechnique
de Montréal, 2900 Boulevard Édouard-Montpetit, Montréal H3T 1J4, Canada
| | - Abdol Hadi Mokarizadeh
- School
of Polymer Science and Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
| | - Daria Camilla Boffito
- Department
of Chemical Engineering, École Polytechnique
de Montréal, 2900 Boulevard Édouard-Montpetit, Montréal H3T 1J4, Canada
| | - Faïçal Larachi
- Department
of Chemical Engineering, Université
Laval, 1065 Avenue de la Médecine, Québec, Québec G1V 0A6, Canada
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3
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Ruiz Pestana L, Head-Gordon T. Evaporation of Water Nanodroplets on Heated Surfaces: Does Nano Matter? ACS NANO 2022; 16:3563-3572. [PMID: 35107985 DOI: 10.1021/acsnano.1c10244] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
While experiments and continuum models have provided a relatively good understanding of the evaporation of macroscopic water droplets, elucidating how sessile nanodroplets evaporate is an open question critical for advancing nanotechnological applications where nanodroplets can play an essential role. Here, using molecular dynamics simulations, we find that evaporating nanodroplets, in contrast to their macroscopic counterparts, are not always in thermal equilibrium with the substrate and that the vapor concentration on the nanodroplet surface does not reach a steady state. As a result, the evaporative behavior of nanodroplets is significantly different. Regardless of hydrophobicity, nanodroplets do not follow conventional evaporation modes but instead exhibit dynamic wetting behavior characterized by huge, non-equilibrium, isovolumetric fluctuations in the contact angle and contact radius. For hydrophilic nanodroplets, the evaporation rate, controlled by the vapor concentration, decays exponentially over time. Hydrophobic nanodroplets follow stretched exponential kinetics arising from the slower thermalization with the substrate. The evaporative half-lifetime of the nanodroplets is directly related to the thermalization time scale and therefore increases monotonically with the hydrophobicity of the substrate. Finally, the evaporative flux profile along the nanodroplet surface is highly nonuniform but does not diverge at the contact line as the macroscopic continuum models predict.
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Affiliation(s)
- Luis Ruiz Pestana
- Department of Civil and Architectural Engineering, University of Miami, Coral Gables, Florida 33146, United States
| | - Teresa Head-Gordon
- Department of Chemistry, Bioengineering, and Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, California 94720, United States
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
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4
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Zhang Z, Zhu Y, Feng W, Jin L, Yang X, Wang Y, Sun CQ, Wang Z. A short-range disordered defect in the double layer ice. J Mol Liq 2021. [DOI: 10.1016/j.molliq.2021.116356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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5
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Wang P, He L, Wang Z. The effect of surface structure and arrangement on wettability of substrate surface. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2021.126165] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Qi C, Zhu Z, Wang C, Zheng Y. Anomalously Low Dielectric Constant of Ordered Interfacial Water. J Phys Chem Lett 2021; 12:931-937. [PMID: 33439661 DOI: 10.1021/acs.jpclett.0c03299] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Despite considerable effort, the dielectric constant of interfacial water at solid surfaces is still not fully understood, thus hindering our understanding of the ubiquitous physical interactions in many materials and biological surfaces. In this study, we used molecular dynamics simulations to show that the parallel dielectric constant at the solid/water interface depends on solid-water interactions as well as the interfacial water structure on various solid crystal faces. In particular, ordered water structures can lead to a significant reduction (∼44%) in the parallel dielectric constant at the solid/water interface compared with that of bulk water. This sharp decrease in the parallel dielectric constant can be attributed to the specific antiferroelectric ordered structure of interfacial water molecules, which significantly suppresses the amplitude of the dipolar fluctuation associated with both the number of hydrogen bonds and the degree of order of interfacial water.
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Affiliation(s)
- Chonghai Qi
- School of Physics, Shandong University, Jinan 250100, China
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
| | - Zhi Zhu
- School of Optical-Electrical Computer Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
| | - Chunlei Wang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Zhangjiang Lab Interdisplinary Research Center, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201210, China
| | - Yujun Zheng
- School of Physics, Shandong University, Jinan 250100, China
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Zhang C, Li X, Wang S, Wang J, Zhu S, Guan S. Does Expanding or Contracting MgO Lattice Really Help with Corrosion Resistance of Mg Surface: Insights from Molecular Dynamics Simulations. ACS OMEGA 2021; 6:1099-1107. [PMID: 33490769 PMCID: PMC7818080 DOI: 10.1021/acsomega.0c03755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 12/04/2020] [Indexed: 06/12/2023]
Abstract
In a humid environment, water droplets on the solid surface can act as a medium to accelerate corrosion. If the solid material has hydrophobic properties, the surface of the material will remain "clean" and corrosion may be retarded to a certain extent. In theory, MgO itself is a hydrophilic material, and we can apply additional stress or strain to change its lattice constant and adjust the wetting behavior of water on the MgO surface, resulting in changes of corrosion resistance. In order to study the effects of MgO lattice expansion or contraction on the wetting behavior of nano-water, molecular dynamics simulations have been performed in this work. It is found that the changes of the lattice constants on the MgO surface can significantly change the wetting tendency. It will alter the interaction forces between water molecules and MgO surfaces, which in turn changes the atomic density profiles, the orientation of OH bonds, and hydrogen bond networks. The contraction of MgO can actually result in the increase of wetting angles of nano-water droplets on the MgO surface and gradually exhibits hydrophobic properties.
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Affiliation(s)
- Chi Zhang
- School
of Materials Science and Engineering, Beijing
Institute of Technology, Beijing 100081, China
| | - Xin Li
- School
of Materials Science and Engineering, Beijing
Institute of Technology, Beijing 100081, China
| | - Shuo Wang
- School
of Materials Science and Engineering, Beijing
Institute of Technology, Beijing 100081, China
| | - Junsheng Wang
- School
of Materials Science and Engineering, Beijing
Institute of Technology, Beijing 100081, China
- Advanced
Research Institute of Multidisciplinary Science, Beijing Institute of Technology, Beijing 100081, China
| | - Shijie Zhu
- School
of Materials Science and Engineering, Zhengzhou
University, Zhengzhou 450002, China
| | - Shaokang Guan
- School
of Materials Science and Engineering, Zhengzhou
University, Zhengzhou 450002, China
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8
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Shevkunov SV. Condensed Water Phase Nuclei in the Field of a Vacancy on a Crystalline Substrate Surface. COLLOID JOURNAL 2020. [DOI: 10.1134/s1061933x20040122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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