1
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Kwan V, Consta S, Malek SMA. Variation of Surface Propensity of Halides with Droplet Size and Temperature: The Planar Interface Limit. J Phys Chem B 2024; 128:193-207. [PMID: 38127582 DOI: 10.1021/acs.jpcb.3c05701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The radial number density profiles of halide and alkali ions in aqueous clusters with equimolar radius ≲1.4 nm, which correspond to ≲255 H2O molecules, have been extensively studied by computations. However, the surface abundance of Cl-, Br-, and I- relative to the bulk interior in these smaller clusters may not be representative of the larger systems. Indeed, here we show that the larger the cluster is, the lower the relative surface abundance of chaotropic halides is. In droplets with an equimolar radius of ≈2.45 nm, which corresponds to ≈2000 H2O molecules, the polarizable halides show a clear number density maximum in the droplet's bulk-like interior. A similar pattern is observed in simulations of the aqueous planar interface with halide salts at room temperature. At elevated temperature the surface propensity of Cl- decreases gradually, while that of I- is partially preserved. The change in the chaotropic halide location at higher temperatures than the room temperature may considerably affect photochemical reactivity in atmospheric aerosols, vapor-liquid nucleation and growth mechanisms, and salt crystallization via solvent evaporation. We argue that the commonly used approach of nullifying parameters in a force field in order to find the factors that determine the ion location does not provide transferable insight into other force fields.
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Affiliation(s)
- Victor Kwan
- Department of Chemistry, The University of Western Ontario, London, ON, Canada N6A 5B7
| | - Styliani Consta
- Department of Chemistry, The University of Western Ontario, London, ON, Canada N6A 5B7
| | - Shahrazad M A Malek
- Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, NL, Canada A1B 3X7
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2
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Nguyen TTP, Raji F, Nguyen CV, Nguyen NN, Nguyen AV. Effects of Charged Surfactants on Interfacial Water Structure and Macroscopic Properties of the Air-Water Interface. Chemphyschem 2023:e202300062. [PMID: 37679310 DOI: 10.1002/cphc.202300062] [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: 01/24/2023] [Revised: 09/06/2023] [Accepted: 09/07/2023] [Indexed: 09/09/2023]
Abstract
Surfactants are used to control the macroscopic properties of the air-water interface. However, the link between the surfactant molecular structure and the macroscopic properties remains unclear. Using sum-frequency generation spectroscopy and molecular dynamics simulations, two ionic surfactants (dodecyl trimethylammonium bromide, DTAB, and sodium dodecyl sulphate, SDS) with the same carbon chain lengths and charge magnitude (but different signs) of head groups interact and reorient interfacial water molecules differently. DTAB forms a thicker but sparser interfacial layer than SDS. It is due to the deep penetration into the adsorption zone of Br- counterions compared to smaller Na+ ones, and also due to the flip-flop orientation of water molecules. SDS alters two distinctive interfacial water layers into a layer where H+ points to the air, forming strong hydrogen bonding with the sulphate headgroup. In contrast, only weaker dipole-dipole interactions with the DTAB headgroup are formed as they reorient water molecules with H+ point down to the aqueous phase. Hence, with more molecules adsorbed at the interface, SDS builds up a higher interfacial pressure than DTAB, producing lower surface tension and higher foam stability at a similar bulk concentration. Our findings offer improved knowledge for understanding various processes in the industry and nature.
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Affiliation(s)
- Thao T P Nguyen
- School of Chemical Engineering and UQ Node of the ARC Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Foad Raji
- School of Chemical Engineering and UQ Node of the ARC Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Cuong V Nguyen
- School of Chemical Engineering and UQ Node of the ARC Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ngoc N Nguyen
- School of Chemical Engineering and UQ Node of the ARC Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Anh V Nguyen
- School of Chemical Engineering and UQ Node of the ARC Centre of Excellence for Enabling Eco-efficient Beneficiation of Minerals, The University of Queensland, Brisbane, QLD 4072, Australia
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3
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Hantal G, Klíma M, McFegan L, Kolafa J, Jedlovszky P. Does the Sign of Charge Affect the Surface Affinity of Simple Ions? J Phys Chem B 2023. [PMID: 37399285 DOI: 10.1021/acs.jpcb.3c02641] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2023]
Abstract
The role the charge sign of simple ions plays in determining their surface affinity in aqueous solutions is investigated by computer simulation methods. For this purpose, the free surface of aqueous solutions of fictitious salts is simulated at finite concentration both with nonpolarizable point-charge and polarizable Gaussian-charge potential models. The salts consist of monovalent cations and anions that are, apart from the sign of their charge, identical to each other. In particular, we consider the small Na+ and the large I- ions together with their charge-inverted counterparts. In an attempt to avoid the interference even between the behavior of cations and anions, we also simulate systems containing only one of the above ions, and determine the free energy profile of these ions across the liquid-vapor interface of water at infinite dilution by potential of mean force (PMF) calculations. The obtained results reveal that, in the case of small ions, the anion is hydrated considerably stronger than the cation due to the close approach of water H atoms, bearing a positive fractional charge. As a consequence, the surface affinity of a small anion is even smaller than that of its cationic counterpart. However, considering that small ions are effectively repelled from the water surface, the importance of this difference is negligible. Further, a change in the hydration energy trends of the two oppositely charged ions is observed with their increasing size. This change is largely attributed to the fact that, with increasing ion size, the factor of 2 in the magnitude of the fractional charge of the closely approaching water atoms (i.e., O around cations and H around anions) outweighs the closer approach of the H than the O atom in the hydration energy. Thus, for large ions, being already surface active themselves, the surface affinity of the anion is larger than that of its positively charged counterpart. Further, such a difference is seen even in the case when the sign of the surface potential favors the adsorption of cations.
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Affiliation(s)
- György Hantal
- Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Straße 82, A-1190 Vienna, Austria
| | - Martin Klíma
- Department of Physical Chemistry, University of Chemistry and Technology, 166 28 Prague 6, Czech Republic
| | - Louisa McFegan
- Budapest University of Technology and Economics, Szt. Gellért tér 4, H-1111 Budapest, Hungary
| | - Jiří Kolafa
- Department of Physical Chemistry, University of Chemistry and Technology, 166 28 Prague 6, Czech Republic
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly Catholic University, Leányka utca 6, H-3300 Eger, Hungary
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4
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McFegan L, Juhász Á, Márton P, Hórvölgyi Z, Jedlovszky-Hajdu A, Hantal G, Jedlovszky P. Surface Affinity of Tetramethylammonium Iodide in Aqueous Solutions: A Combined Experimental and Computer Simulation Study. J Phys Chem B 2023. [PMID: 37276239 DOI: 10.1021/acs.jpcb.3c01370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The surface affinity of tetramethylammonium iodide (TMAI) in aqueous solutions is investigated by surface tension measurements and molecular dynamics computer simulations. Experiments, performed in the entire composition range of solubility using the pendant drop method with two different setups, clearly reveal that TMAI is a weakly capillary active salt. Computer simulations performed with the AMBER force field reproduce the experimental data very well, while two other major force fields (i.e., CHARMM and OPLS) can still reproduce the experimental trend qualitatively; however, even qualitative reproduction of the experimental trend requires scaling down the ion charges according to the Leontyev-Stuchebrukhov correction. On the other hand, the GROMOS force field fails in reproducing the experimentally confirmed capillary activity of TMAI. Molecular dynamics simulation results show that, among the two ions, iodide has a clearly larger surface affinity than tetramethylammonium (TMA+). Further, the adsorption of the I- anions is strictly limited to the first molecular layer beneath the liquid-vapor interface, which is followed by several layers of their depletion. On the other hand, the net negative charge of the surface layer, caused by the excess amount of I- with respect to TMA+, is compensated by a diffuse layer of adsorbed TMA+ cations, extending to or beyond the fourth molecular layer beneath the liquid surface.
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Affiliation(s)
- Louisa McFegan
- Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Szt. Gellért tér 4, H-1111 Budapest, Hungary
| | | | - Péter Márton
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
| | - Zoltán Hórvölgyi
- Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, Budafoki út 8, H-1111 Budapest, Hungary
| | | | - György Hantal
- Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Straße 82, A-1190 Vienna, Austria
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly Catholic University, Leányka utca 6, H-3300 Eger, Hungary
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5
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Pandey PK, Chandra A. Mechanism, Kinetics, and Potential of Mean Force of Evaporation of Water from Aqueous Sodium Chloride Solutions of Varying Concentrations. J Phys Chem B 2023; 127:4602-4612. [PMID: 37163726 DOI: 10.1021/acs.jpcb.2c09004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The mechanism, kinetics, and potential of mean force of evaporation of water from aqueous NaCl solutions are investigated through both unbiased molecular dynamics simulations and also biased simulations using the umbrella sampling method. The results are obtained for aqueous solutions of three different NaCl concentrations ranging from 0.6 to 6.0 m and also for pure water. The rate of evaporation is found to decrease in the presence of ions. It is found that the process of evaporation of a surface water molecule from ionic solutions can be triggered through its collision with another water or chloride ion. Such collisions provide the additional kinetic energy that is required for evaporation. However, when the collision takes place with a Cl- ion, the evaporation of the escaping water also involves a collision with water in the vicinity of the ion at the same time along with the ion-water collision. These two collisions together provide the required kinetic energy for escape of the evaporating water molecule. Thus, the mechanism of evaporation process of ionic solutions can be more complex than that of pure water. The potential of mean force (PMF) of evaporation is found to be positive and it increases with increasing ion concentration. Also, no barrier in the PMF is found to be present for the condensation of water from vapor phase to the surfaces of the solutions. A detailed analysis of the unsuccessful evaporation attempts by surface water molecules is also made in the current study.
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Affiliation(s)
- Prashant Kumar Pandey
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, India 208016
| | - Amalendu Chandra
- Department of Chemistry, Indian Institute of Technology Kanpur, Uttar Pradesh, India 208016
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6
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Premadasa UI, Dong D, Stamberga D, Custelcean R, Roy S, Ma YZ, Bocharova V, Bryantsev VS, Doughty B. Chemical Feedback in the Self-Assembly and Function of Air-Liquid Interfaces: Insight into the Bottlenecks of CO 2 Direct Air Capture. ACS APPLIED MATERIALS & INTERFACES 2023; 15:19634-19645. [PMID: 36944180 DOI: 10.1021/acsami.3c00719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
As fossil fuels remain a major source of energy throughout the world, developing efficient negative emission technologies, such as direct air capture (DAC), which remove carbon dioxide (CO2) from the air, becomes critical for mitigating climate change. Although all DAC processes involve CO2 transport from air into a sorbent/solvent, through an air-solid or air-liquid interface, the fundamental roles the interfaces play in DAC remain poorly understood. Herein, we study the interfacial behavior of amino acid (AA) solvents used in DAC through a combination of vibrational sum frequency generation spectroscopy and molecular dynamics simulations. This study revealed that the absorption of atmospheric CO2 has antagonistic effects on subsequent capture events that are driven by changes in bulk pH and specific ion effects that feedback on surface organization and interactions. Among the three AAs (leucine, valine, and phenylalanine) studied, we identify and separate behaviors from CO2 loading, chemical changes, variations in pH, and specific ion effects that tune structural and chemical degrees of freedom at the air-aqueous interface. The fundamental mechanistic findings described here are anticipated to enable new approaches to DAC based on exploiting interfaces as a tool to address climate change.
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Affiliation(s)
- Uvinduni I Premadasa
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dengpan Dong
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Diana Stamberga
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Radu Custelcean
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Santanu Roy
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Ying-Zhong Ma
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Vera Bocharova
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Vyacheslav S Bryantsev
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Benjamin Doughty
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
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7
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Yang H, Gladich I, Boucly A, Artiglia L, Ammann M. Orcinol and resorcinol induce local ordering of water molecules near the liquid-vapor interface. ENVIRONMENTAL SCIENCE: ATMOSPHERES 2022; 2:1277-1291. [PMID: 36561553 PMCID: PMC9648629 DOI: 10.1039/d2ea00015f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 08/17/2022] [Indexed: 12/25/2022]
Abstract
Resorcinol and orcinol are simple members of the family of phenolic compounds present in particulate matter in the atmosphere; they are amphiphilic in nature and thus surface active in aqueous solution. Here, we used X-ray photoelectron spectroscopy to probe the concentration of resorcinol (benzene-1,3-diol) and orcinol (5-methylbenzene-1,3-diol) at the liquid-vapor interface of aqueous solutions. Qualitatively consistent surface propensity and preferential orientation was obtained by molecular dynamics simulations. Auger electron yield near-edge X-ray absorption fine structure (NEXAFS) spectroscopy was used to probe the hydrogen bonding (HB) structure, indicating that the local structure of water molecules near the surface of the resorcinol and orcinol solutions tends towards a larger fraction of tetrahedrally coordinated molecules than observed at the liquid-vapor interface of pure water. The order parameter obtained from the molecular dynamics simulations confirm these observations. This effect is being discussed in terms of the formation of an ordered structure of these molecules at the surface leading to patterns of hydrated OH groups with distances among them that are relatively close to those in ice. These results suggest that the self-assembly of phenolic species at the aqueous solution-air interface could induce freezing similar to the case of fatty alcohol monolayers and, thus, be of relevance for ice nucleation in the atmosphere. We also attempted at looking at the changes of the O 1b1, 3a2 and 1b2 molecular orbitals of liquid water, which are known to be sensitive to the HB structure as well, in response to the presence of resorcinol and orcinol. However, these changes remained negligible within uncertainty for both experimentally obtained valence spectra and theoretically calculated density of states.
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Affiliation(s)
- Huanyu Yang
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland,Institute of Atmospheric and Climate Science, ETH Zürich8092 ZürichSwitzerland
| | - Ivan Gladich
- Qatar Environment & Energy Research Institute, Hamad Bin Khalifa UniversityP.O. Box 34110DohaQatar
| | - Anthony Boucly
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland,Electrochemistry Laboratory, Paul Scherrer Institut5232 VilligenSwitzerland
| | - Luca Artiglia
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland,Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland
| | - Markus Ammann
- Laboratory of Environmental Chemistry, Paul Scherrer Institut5232 VilligenSwitzerland
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8
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May sediments affect the inhibiting properties of NaCl on CH4 and CO2 hydrates formation? an experimental report. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119300] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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9
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Mangin T, Schurhammer R, Wipff G. Liquid-Liquid Extraction of the Eu(III) Cation by BTP Ligands into Ionic Liquids: Interfacial Features and Extraction Mechanisms Investigated by MD Simulations. J Phys Chem B 2022; 126:2876-2890. [PMID: 35389658 DOI: 10.1021/acs.jpcb.2c00488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
What happens at the ionic-liquid (IL)/water interface when the Eu3+ cation is complexed and extracted by bis(dimethyltriazinyl) pyridine "BTP" ligands has been investigated by molecular dynamics and potential of mean force simulations on the interface crossing by key species: neutral BTP, its protonated BTPH+ form, Eu3+, and the Eu(BTP)33+ complex. At both the [BMI][Tf2N]/water and [OMI][Tf2N]/water interfaces, neither BTP nor Eu(BTP)33+ are found to adsorb. The distribution of Eu(BTP)23+ and Eu(BTP)3+ precursors of Eu(BTP)33+, and of their nitrate adducts, implies the occurrence of a stepwise complexation process in the interfacial domain, however. The analysis of the ionic content of the bulk phases and of their interface before and after extraction highlights the role of charge buffering by interfacial IL cations and anions, by different amounts depending on the IL. Comparison of ILs with octanol as the oil phase reveals striking differences regarding the extraction efficiency, the affinity of Eu(BTP)33+ for the interface, the effects of added nitric acid and of counterions (NO3- vs Tf2N-), charge neutralization mechanisms, and the extent of "oil" heterogeneity. Extraction into octanol is suggested to proceed via adsorption at the surface of water pools, nanoemulsions, or droplets, with marked counterion effects.
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Affiliation(s)
- Thomas Mangin
- Laboratoire MSM, UMR CNRS 7140, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Rachel Schurhammer
- Laboratoire MSM, UMR CNRS 7140, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France
| | - Georges Wipff
- Laboratoire MSM, UMR CNRS 7140, Université de Strasbourg, 4 Rue Blaise Pascal, 67000 Strasbourg, France
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10
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Lbadaoui-Darvas M, Idrissi A, Jedlovszky P. Computer Simulation of the Surface of Aqueous Ionic and Surfactant Solutions. J Phys Chem B 2022; 126:751-765. [PMID: 34904437 PMCID: PMC9161821 DOI: 10.1021/acs.jpcb.1c08553] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The surface of aqueous solutions of simple salts was not the main focus of scientific attention for a long while. Considerable interest in studying such systems has only emerged in the past two decades, following the pioneering finding that large halide ions, such as I-, exhibit considerable surface affinity. Since then, a number of issues have been clarified; however, there are still several unresolved points (e.g., the effect of various salts on lateral water diffusion at the surface) in this respect. Computer simulation studies of the field have largely benefited from the appearance of intrinsic surface analysis methods, by which the particles staying right at the boundary of the two phases can be unambiguously identified. Considering complex ions instead of simple ones opens a number of interesting questions, both from the theoretical point of view and from that of the applications. Besides reviewing the state-of-the-art of intrinsic surface analysis methods as well as the most important advances and open questions concerning the surface of simple ionic solutions, we focus on two such systems in this Perspective, namely, the surface of aqueous mixtures of room temperature ionic liquids and that of ionic surfactants. In the case of the former systems, for which computer simulation studies have still scarcely been reported, we summarize the theoretical advances that could trigger such investigations, which might well be of importance also from the point of view of industrial applications. Computer simulation methods are, on the other hand, widely used in studies of the surface of surfactant solutions. Here we review the most important theoretical advances and issues to be addressed and discuss two areas of applications, namely, the inclusion of information gathered from such simulations in large scale atmospheric models and the better understanding of the airborne transmission of viruses, such as SARS-CoV-2.
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Affiliation(s)
- Mária Lbadaoui-Darvas
- Laboratory
of Atmospheric Processes and their Impacts, EPFL, CH-1015 Lausanne, Switzerland
| | - Abdenacer Idrissi
- CNRS,
UMR 8516 -LASIRe - Laboratoire Avancé de Spectroscopie pour
les Interactions la Réactivité et l’environnement, University of Lille, F-5900 Lille, France
| | - Pál Jedlovszky
- Department
of Chemistry, Eszterházy Károly
University, Leányka utca 6, H-3300 Eger, Hungary,
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11
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Bredt AJ, Kim Y, Mendes de Oliveira D, Urbina AS, Slipchenko LV, Ben-Amotz D. Expulsion of Hydroxide Ions from Methyl Hydration Shells. J Phys Chem B 2022; 126:869-877. [PMID: 35077175 DOI: 10.1021/acs.jpcb.1c08420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The affinity of hydroxide ions for methyl hydration shells is assessed using a combined experimental and theoretical analysis of tert-butyl alcohol (TBA) dissolved in pure water and aqueous NaOH and NaI. The experimental results are obtained using Raman multivariate curve resolution (Raman-MCR) and a new three-component total least squares (Raman-TLS) spectral decomposition strategy used to highlight vibrational perturbations resulting from interactions between TBA and aqueous ions. The experiments are interpreted and extended with the aid of effective fragment potential molecular dynamics (EFP-MD) simulations, as well as Kirkwood-Buff calculations and octanol/water partition measurements, to relate TBA-ion distribution functions to TBA solubility changes. The combined experimental and simulation results reveal that methyl group hydration shells more strongly expel hydroxide than iodide anions, whose populations near the methyl groups of TBA are predicted to be correlated with sodium counterion localization near the TBA hydroxyl group.
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Affiliation(s)
- Aria J Bredt
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Yongbin Kim
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | | | - Andres S Urbina
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Lyudmila V Slipchenko
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
| | - Dor Ben-Amotz
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907, United States
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12
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Mrozik W, Minofar B, Thongsamer T, Wiriyaphong N, Khawkomol S, Plaimart J, Vakros J, Karapanagioti H, Vinitnantharat S, Werner D. Valorisation of agricultural waste derived biochars in aquaculture to remove organic micropollutants from water - experimental study and molecular dynamics simulations. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2021; 300:113717. [PMID: 34547568 PMCID: PMC8542888 DOI: 10.1016/j.jenvman.2021.113717] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 08/20/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
In this work, we evaluated the valorisation of agricultural waste materials by transforming coconut husks and shells, corncobs and rice straw into biochar for water treatment in aquaculture. We compared the biochars' suitability for removal of organic micropollutants (acetaminophen, oxytetracycline, tetracycline, enrofloxacin, atrazine, diuron and diclofenac) from surface water needed for aquaculture. The biochars were prepared by three methods ranging from inexpensive drum kilns (200 °C) to pyrolysis with biogasfication (350-750 °C). Overall, antibiotics tetracycline and enrofloxacin were the most strongly sorbed micropollutants, and coconut husk biochar prepared at 750 °C was the best sorbent material. Molecular Dynamics simulations indicated that the major sorption mechanism is via π-π stacking interactions and there is a possibility of multilayer sorption for some of the micropollutants. We observed, a strong impact of ionic strength (salinity), which is an important consideration in coastal aquaculture applications. High salinity decreased the sorption for antibiotics oxytetracycline, tetracycline and enrofloxacin but increased diclofenac, atrazine and diuron sorption. We considered coconut husk biochar produced in drum kilns the most practical option for biochar applications in small-scale coastal aquacultures in South Asia. Pilot trials of canal water filtration at an aquaculture farm revealed that micropollutant sorption by coconut husk biochar under real-world conditions might be 10-500 times less than observed in the laboratory studies. Even so, biochar amendment of sand enhanced the micropollutant retention, which may facilitate subsequent biodegradation and improve the quality of brackish surface water used for food production in coastal aquaculture.
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Affiliation(s)
- Wojciech Mrozik
- School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom.
| | - Babak Minofar
- Laboratory of Structural Biology and Bioinformatics, Institute of Microbiology of the Czech Academy of Sciences, Zámek 136, 37333, Nové Hrady, Czech Republic.
| | - Thunchanok Thongsamer
- Environmental Technology Program, School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, 126 Pracha-uthit road, Bangmod, Bangkok, 10140, Thailand
| | - Nathacha Wiriyaphong
- Environmental Technology Program, School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, 126 Pracha-uthit road, Bangmod, Bangkok, 10140, Thailand
| | - Sasiwimol Khawkomol
- Energy and Environmental Engineering Center, Faculty of Engineering at Kamphaeng Saen, Kasetsart University, Nakhon Pathom, Thailand
| | - Jidapa Plaimart
- School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
| | - John Vakros
- Department of Chemistry, University of Patras, Patras, 26504, Greece
| | | | - Soydoa Vinitnantharat
- Environmental Technology Program, School of Energy, Environment and Materials, King Mongkut's University of Technology Thonburi, 126 Pracha-uthit road, Bangmod, Bangkok, 10140, Thailand
| | - David Werner
- School of Engineering, Newcastle University, Newcastle upon Tyne, NE1 7RU, United Kingdom
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13
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Prelesnik J, Maibaum L. Effects of Salts on the Solvation of Hydrophobic Objects in Water. J Phys Chem B 2021; 125:11036-11043. [PMID: 34583505 DOI: 10.1021/acs.jpcb.1c06833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The solvation of large, hydrophobic objects in water is facilitated by the formation of a low-density region surrounding the solute that is separated from the bulk liquid by an interface, which has a structure that resembles that between a liquid and its vapor. We study the effect of dissolved sodium chloride on the thermodynamics of solvation and on the solvent structure surrounding hydrophobic solutes in the size regime where this interface is not yet fully formed. Using biased Molecular Dynamics computer simulations, we calculate solvation free energies and orientational distributions of water molecules at different salt concentrations and solute sizes. We find that while the effects of sodium chloride on thermodynamic properties are small, the ions' response to the presence of a hydrophobic solute differs significantly from that of the water. Our findings provide mechanistic insight into how our understanding of hydrophobic solvation in water can be extended to electrolyte solutions.
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Affiliation(s)
- Jesse Prelesnik
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Lutz Maibaum
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
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14
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Hantal G, Sega M, Horvai G, Jedlovszky P. Contribution of Different Molecules and Moieties to the Surface Tension in Aqueous Surfactant Solutions. II: Role of the Size and Charge Sign of the Counterions. J Phys Chem B 2021; 125:9005-9018. [PMID: 34319728 DOI: 10.1021/acs.jpcb.1c04216] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Understanding the role of the counterion species in surfactant solutions is a complicated task, made harder by the fact that, experimentally, it is not possible to vary independently bulk and surface quantities. Here, we perform molecular dynamics simulations at constant surface coverage of the liquid/vapor interface of lithium, sodium, potassium, rubidium, and cesium dodecyl sulfate aqueous solutions. We investigate the effect of counterion type and charge sign on the surface tension of the solution, analyzing the contribution of different species and moieties to the lateral pressure profile. The observed trends are qualitatively compatible with the Hofmeister series, with the notable exception of sodium. We point out a possible shortcoming of what is at the moment, in our experience, the most realistic nonpolarizable force field (CHARMM36) that includes the parametrization for the whole series of alkali counterions. In the artificial system where the counterion and surfactant charges are inverted in sign, the counterions become considerably harder. This charge inversion changes considerably the surface tension contributions of the counterions, surfactant headgroups, and water molecules, stressing the key role of the hardness of the counterions in this respect. However, the hydration free energy gain of the counterions, occurring upon charge inversion, is compensated by the concomitant free energy loss of the headgroups and water molecules, leading to a negligible change in the surface tension of the entire system.
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Affiliation(s)
- György Hantal
- Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Straße 82, A-1190 Vienna, Austria.,Department of Chemistry, Eszterházy Károly University, Leányka utca 6, H-3300 Eger, Hungary
| | - Marcello Sega
- Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11),Fürther Straße 248, D-90429 Nürnberg, Germany
| | - George Horvai
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, H-1111 Budapest, Hungary
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly University, Leányka utca 6, H-3300 Eger, Hungary
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15
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Kumar N, Servis MJ, Clark AE. Uranyl Speciation in the Presence of Specific Ion Gradients at the Electrolyte/Organic Interface. SOLVENT EXTRACTION AND ION EXCHANGE 2021. [DOI: 10.1080/07366299.2021.1954323] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Nitesh Kumar
- Department of Chemistry, Washington State University, Pullman, Washington, USA
| | - Michael J. Servis
- Department of Chemistry, Washington State University, Pullman, Washington, USA
| | - Aurora E. Clark
- Department of Chemistry, Washington State University, Pullman, Washington, USA
- Pacific Northwest National Laboratory, Richland, Washington, USA
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16
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Adel T, Ng KC, Vazquez de Vasquez MG, Velez-Alvarez J, Allen HC. Insight into the Ionizing Surface Potential Method and Aqueous Sodium Halide Surfaces. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:7863-7874. [PMID: 34152764 DOI: 10.1021/acs.langmuir.1c00465] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Complementing the microscopic picture of the surface structure of electrolyte solutions set out by previous theoretical and experimental studies, the ionizing surface potential technique offers a unique approach to quantifying the impact of aqueous inorganic ions upon the interfacial electric field of the air-aqueous interface. In this Feature Article, we review the vulnerability of theoretical and empirically derived χwater values as a normative reference for aqueous ion surface potentials. Instead, we recognize and evaluate aqueous ion surface potentials relative to well-known ionic surfactants cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS). Additionally, we also explore factors that impact the magnitude of the measured surface potentials using the ionizing method, particularly in the type of reference electrode and ionizing gas environment. With potential measurements of sodium halide solutions, we show that iodide has a dominant effect on the air-aqueous electric field. Compared to chloride and bromide, iodide is directly observed with a net negatively charged surface electric field at all salt concentrations measured (0.2 to 3.0 mol/kg water). Also, above the 2 M region, bromide is observed with a net negatively charged surface. Although several scenarios contribute to this effect, it is most likely due to the surface enrichment of bromide and iodide. While the results of this study are pertinent to determining the specific interfacial reactivity of aqueous halides, these anions seldom transpire as single-halide systems in the natural environment. Therefore, we also provide an outlook on future research concerning surface potential methods and more complex aqueous electrolyte systems.
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Affiliation(s)
- Tehseen Adel
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Ka Chon Ng
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Maria G Vazquez de Vasquez
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Juan Velez-Alvarez
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
| | - Heather C Allen
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210, United States
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17
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Kobrak MN, Nykypanchuk D, Janssen CHC. Relationship between liquid nanoscale structure in solvents and the strength of the Hofmeister effect in extraction experiments. Phys Chem Chem Phys 2021; 23:6266-6277. [PMID: 33735349 DOI: 10.1039/d0cp05973k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In this study, we used mixtures of carboxylic acids and amines as solvents for the liquid-liquid extraction of copper salts with various anions from aqueous phase, and systematically varied the acid/amine ratio to determine its influence on extraction efficiency. The organic phases resulting from these extraction experiments were studied using small-angle X-ray scattering (SAXS), establishing a connection between the extraction process and the liquid structure. A relationship is found between the extent of extraction for the metal salt, the strength of the Hofmeister effect of the anions of the salt, and the characteristic lengthscale of the observed liquid nanoscale structure before and after extraction.
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Affiliation(s)
- Mark N Kobrak
- Department of Chemistry, Brooklyn College of the City University of New York, 2900 Bedford Ave., Brooklyn, NY 11210, USA and Department of Chemistry, Graduate Center of the City University of New York, 365 Fifth Ave., New York, NY 10016, USA
| | - Dmytro Nykypanchuk
- Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA
| | - Camiel H C Janssen
- Departamento de Ingeniería Química, Facultad de Química, Universidad Nacional Autónoma de México, Circuito Exterior S/N, Coyoacán, Cd. Universitaria, 04510 Ciudad de México, Mexico.
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18
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Hantal G, Kolafa J, Sega M, Jedlovszky P. Single-Particle Dynamics at the Intrinsic Surface of Aqueous Alkali Halide Solutions. J Phys Chem B 2021; 125:665-679. [PMID: 33423500 DOI: 10.1021/acs.jpcb.0c09989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The distribution of ions in the proximity of the liquid-vapor interface of their aqueous solution has been the subject of an intense debate during the last decade. The effects of ionic polarizability have been one of its salient aspects. Much less has been said about the corresponding dynamical properties, which are substantially unexplored. Here, we investigate the single-particle dynamics at the liquid-vapor interface of several alkali halide solutions, using molecular dynamics simulations with polarizable and nonpolarizable force fields and intrinsic surface analysis. We analyze the diffusion coefficient, residence time, and velocity autocorrelation function of water and ions and investigate how these properties depend on the molecular layer where they reside. While anions are found in the first molecular layer for relatively long times, cations are only making quick excursions into it, thanks to thermal fluctuations. The in-layer residence time of ions and their molar fraction in the layer turned out to be linearly dependent on each other. We interpret this unexpected result using a simple two-state model. In addition, we found that, unlike water and other neat molecular liquids that show a different diffusion mechanism at the surface than in the bulk of their liquid phase, ions do not enjoy enhanced mobility in the surface layer of their aqueous solution. This result indicates that ions in the surface layer are shielded by their nearest water neighbors from being exposed to the vapor phase as much as possible. Such positions are available for the ions at the negatively curved troughs of the molecularly rugged liquid surface.
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Affiliation(s)
- György Hantal
- Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Straße 82, Vienna A-1190, Austria
| | - Jiří Kolafa
- Department of Physical Chemistry, University of Chemistry and Technology, Prague CZ-166 28 Prague 6, Czech Republic
| | - Marcello Sega
- Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Fürther Straße 248, Nürnberg D-90429, Germany
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly University, Leányka utca 6, Eger H-3300, Hungary
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19
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Mosallanejad S, Oluwoye I, Altarawneh M, Gore J, Dlugogorski BZ. Interfacial and bulk properties of concentrated solutions of ammonium nitrate. Phys Chem Chem Phys 2020; 22:27698-27712. [PMID: 33242055 DOI: 10.1039/d0cp04874g] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We conducted molecular dynamics (MD) simulations to calculate the density and surface tension of concentrated ammonium nitrate (AN) solutions up to the solubility limit of ammonium nitrate in water, by combining the SPC/E, SPCE/F and TIP4P/2005 water models with OPLS model for ammonium and nitrate ions. This is the first time that the properties of concentrated solutions of nitrates, especially AN, have been studied by molecular dynamics. We effectively account for the polarisation effects by the electronic continuum correction (ECC), practically realised via rescaling of the ionic charges. We found that, the full-charge force field MD simulations overestimate the experimental results, as the ions experience repulsion from the interface and prefer to remain in the subsurface layer and the bulk solution. In contrast, reducing the ionic charges results in the behaviour that fits well with the experimental data. The nitrate anions display a greater propensity for the interface than the ammonium cations. We accurately predict both the density and the rise in the surface tension of concentrated solutions of AN, recommending TIP4P/2005 for water and the scaled-charge OPLS model (OPLS/ECC) for the ions in the solutions. We observe that, the adsorption of anions to the interface accompanies their depletion in the subsurface layer, which is preferentially occupied by cations, resulting in the formation of the electric double layer. We demonstrate the ion deficiency for up to 3 Å below the surface and establish the requirement to include the polarisability effects in the OPLS model for AN. While these results confirmed the findings of the previous studies for dilute solutions, they are new in the solubility limit. Concentrated solutions exhibit a strong effect of the abundance of solute on the coordination numbers of ions and on the degree of ion pairing. Surprisingly, ion pairing decreases significantly at the interface compared with the bulk. The present study identifies OPLS/ECC, along with TIP4P/2005, to yield accurate predictions of physical properties of concentrated AN, with precision required for industrial applications, such as a formulation of emulsion and fuel-oil explosives that now predominate the civilian use of AN. An application of this model will allow one to predict the surface properties of supersaturated solutions of AN which fall outside the capability of the present laboratory experiments but are important industrially.
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Affiliation(s)
- Sara Mosallanejad
- Discipline of Chemistry and Physics, College of Science, Health, Engineering and Education, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia
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20
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Hantal G, Horváth RA, Kolafa J, Sega M, Jedlovszky P. Surface Affinity of Alkali and Halide Ions in Their Aqueous Solution: Insight from Intrinsic Density Analysis. J Phys Chem B 2020; 124:9884-9897. [PMID: 33084342 DOI: 10.1021/acs.jpcb.0c05547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The surface tension of all aqueous alkali halide solutions is higher than that of pure water. According to the Gibbs adsorption equation, this indicates a net depletion of these ions in the interfacial region. However, simulations and experiments show that large, soft ions, such as I-, can accumulate at the liquid/vapor interface. The presence of a loose hydration shell is usually considered to be the reason for this behavior. In this work, we perform computer simulations to characterize the liquid-vapor interface of aqueous alkali chloride and sodium halide solutions systematically, considering all ions from Li+ to Cs+ and from F- to I-. Using computational methods for the removal of surface fluctuations, we analyze the structure of the interface at a dramatically enhanced resolution, showing that the positive excess originates in the very first molecular layer and that the next 3-4 layers account for the net negative excess. With the help of a fictitious system with charge-inverted ion pairs, we also show that it is not possible to rationalize the surface affinity of ions in solutions in terms of the properties of anions and cations separately. Moreover, the surface excess is generally dominated by the smaller of the two ions.
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Affiliation(s)
- György Hantal
- Institute of Physics and Materials Science, University of Natural Resources and Life Sciences, Peter Jordan Straße 82, A-1190 Vienna, Austria
| | - Réka A Horváth
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Szt. Gellért tér 4, H-1111 Budapest, Hungary
| | - Jiří Kolafa
- Department of Physical Chemistry, University of Chemistry and Technology, 166 28 Prague 6, Czech Republic
| | - Marcello Sega
- Forschungszentrum Jülich GmbH, Helmholtz Institute Erlangen-Nürnberg for Renewable Energy (IEK-11), Fürther Straße 248, D-90429 Nürnberg, Germany
| | - Pál Jedlovszky
- Department of Chemistry, Eszterházy Károly University, Leányka utca 6, H-3300 Eger, Hungary
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21
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Le Breton G, Joly L. Molecular modeling of aqueous electrolytes at interfaces: Effects of long-range dispersion forces and of ionic charge rescaling. J Chem Phys 2020; 152:241102. [PMID: 32610967 DOI: 10.1063/5.0011058] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Molecular dynamics simulations of aqueous electrolytes generally rely on empirical force fields, combining dispersion interactions-described by a truncated Lennard-Jones (LJ) potential-and electrostatic interactions-described by a Coulomb potential computed with a long-range solver. Recently, force fields using rescaled ionic charges [electronic continuum correction (ECC)], possibly complemented with rescaling of LJ parameters [ECC rescaled (ECCR)], have shown promising results in bulk, but their performance at interfaces has been less explored. Here, we started by exploring the impact of the LJ potential truncation on the surface tension of a sodium chloride aqueous solution. We show a discrepancy between the numerical predictions for truncated LJ interactions with a large cutoff and for untruncated LJ interactions computed with a long-range solver, which can bias comparison of force field predictions with experiments. Using a long-range solver for LJ interactions, we then show that an ionic charge rescaling factor chosen to correct long-range electrostatic interactions in bulk accurately describes image charge repulsion at the liquid-vapor interface, and the rescaling of LJ parameters in ECCR models-aimed at capturing local ion-ion and ion-water interactions in bulk- describes well the formation of an ionic double layer at the liquid-vapor interface. Overall, these results suggest that the molecular modeling of aqueous electrolytes at interfaces would benefit from using long-range solvers for dispersion forces and from using ECCR models, where the charge rescaling factor should be chosen to correct long-range electrostatic interactions.
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Affiliation(s)
- Guillaume Le Breton
- Département de Physique, École Normale Supérieure de Lyon, 46 Allée d'Italie, Lyon Cedex 07, France
| | - Laurent Joly
- Univ. Lyon, Univ. Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
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22
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Hao H, Xie Q, Ai J, Wang Y, Bian H. Specific counter-cation effect on the molecular orientation of thiocyanate anions at the aqueous solution interface. Phys Chem Chem Phys 2020; 22:10106-10115. [PMID: 32342973 DOI: 10.1039/d0cp00974a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Understanding the interfacial structure of aqueous electrolyte solutions is important and relevant to a wide range of systems, ranging from atmospheric aerosols to electrochemistry, and biological environments. Though significant efforts have been made to unravel the interfacial structure of water molecules, the structure and dynamics of ions at the interface have not yet been fully elucidated. Here, the interfacial structure of the aqueous solution was investigated directly by monitoring the thiocyanate (SCN-) anions using surface-specific sum frequency generation (SFG) vibrational spectroscopy. The molecular orientation of the SCN- anions and their adsorption behavior at the air/water interface were systematically determined by quantitative polarization analysis. The transition dipole of the CN stretching of the SCN- anion is oriented around 44° from the surface normal of the NaSCN aqueous solution surface and remained unchanged with the bulk concentration varying from 1 mol kg-1 to 13 mol kg-1. The free energy of adsorption of SCN- anions at the air/water interface was determined to be -1.53 ± 0.04 kcal mol-1. Furthermore, a new SFG peak positioned at 2080 cm-1 in the ppp polarization combination was observed at the air/15.0 mol kg-1 NaSCN aqueous solution interface for the first time. Concentration-dependent SFG analysis and density functional theory (DFT) calculation further revealed that the SCN- anions form an ion clustering structure at the air/water interface. The subtle and specific Na+ and K+ counter-cation effects on the interfacial structure of the SCN- anions at the aqueous solution interface were also observed, which showed that ion cooperativity plays an important role in affecting the interfacial structure of ions at the air/water interface. The results are expected to yield significant insights into the understanding of the structure of aqueous solution surfaces and the molecular level mechanism of the cationic Hofmeister effect.
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Affiliation(s)
- Hongxing Hao
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
| | - Qing Xie
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
| | - Jingwen Ai
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
| | - Yuan Wang
- Institute of Science and Technology, University of Sanya, Sanya, Hainan 572022, China
| | - Hongtao Bian
- Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an, 710119, China.
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23
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Gladich I, Chen S, Vazdar M, Boucly A, Yang H, Ammann M, Artiglia L. Surface Propensity of Aqueous Atmospheric Bromine at the Liquid-Gas Interface. J Phys Chem Lett 2020; 11:3422-3429. [PMID: 32283032 DOI: 10.1021/acs.jpclett.0c00633] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Multiphase reactions of halide ions in aqueous solutions exposed to the atmosphere initiate the formation of molecular halogen compounds in the gas phase. Their photolysis leads to halogen atoms, which are catalytic sinks for ozone, making these processes relevant for the regional and global tropospheric ozone budget. The affinity of halide ions in aqueous solution for the liquid-gas interface, which may influence their reactivity with gaseous species, has been debated. Our study focuses on the surface properties of the bromide ion and its oxidation products. In situ X-ray photoelectron spectroscopy carried out on a liquid jet combined with classical and first-principles molecular dynamics calculations was used to investigate the interfacial depth profile of bromide, hypobromite, hypobromous acid, and bromate. The simulated core electron binding energies support the experimentally observed values, which follow a correlation with bromine oxidation state for the anion series. Bromide ions are homogeneously distributed in the solution. Hypobromous acid, a key species in the multiphase cycling of bromine, is the only species showing surface propensity, which suggests a more important role of the interface in multiphase bromine chemistry than thought so far.
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Affiliation(s)
- Ivan Gladich
- Qatar Environment & Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 34110, Doha, Qatar
| | - Shuzhen Chen
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
- Institute of Atmospheric and Climate Sciences, ETH Zurich, 8092 Zurich, Switzerland
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia
| | - Anthony Boucly
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - Huanyu Yang
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
- Institute of Atmospheric and Climate Sciences, ETH Zurich, 8092 Zurich, Switzerland
| | - Markus Ammann
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
| | - Luca Artiglia
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
- Laboratory for Sustainable Chemistry and Catalysis, Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen, Switzerland
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24
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Polster JW, Acar ET, Aydin F, Zhan C, Pham TA, Siwy ZS. Gating of Hydrophobic Nanopores with Large Anions. ACS NANO 2020; 14:4306-4315. [PMID: 32181640 DOI: 10.1021/acsnano.9b09777] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Understanding ion transport in nanoporous materials is critical to a wide variety of energy and environmental technologies, ranging from ion-selective membranes, drug delivery, and biosensing, to ion batteries and supercapacitors. While nanoscale transport is often described by continuum models that rely on a point charge description for ions and a homogeneous dielectric medium for the solvent, here, we show that transport of aqueous solutions at a hydrophobic interface can be highly dependent on the size and hydration strength of the solvated ions. Specifically, measurements of ion current through single silicon nitride nanopores that contain a hydrophobic-hydrophilic junction show that transport properties are dependent not only on applied voltage but also on the type of anion. We find that in Cl--containing solutions the nanopores only conducted ionic current above a negative voltage threshold. On the other hand, introduction of large polarizable anions, such as Br- and I-, facilitated the pore wetting, making the pore conductive at all examined voltages. Molecular dynamics simulations revealed that the large anions, Br- and I-, have a weaker solvation shell compared to that of Cl- and consequently were prone to migrate from the aqueous solution to the hydrophobic surface, leading to the anion accumulation responsible for pore wetting. The results are essential for designing nanoporous systems that are selective to ions of the same charge, for realization of ion-induced wetting in hydrophobic pores, as well as for a fundamental understanding on the role of ion hydration shell on the properties of solid/liquid interfaces.
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Affiliation(s)
- Jake W Polster
- Department of Chemistry, University of California, Irvine, California 92697, United States
| | - Elif Turker Acar
- Department of Chemistry, University of California, Irvine, California 92697, United States
- Department of Chemistry, Faculty of Engineering, Istanbul University - Cerrahpasa, Avcılar, 34320 Istanbul, Turkey
| | - Fikret Aydin
- Quantum Simulations Group and Laboratory for Energy Applications for the Future, Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Cheng Zhan
- Quantum Simulations Group and Laboratory for Energy Applications for the Future, Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Tuan Anh Pham
- Quantum Simulations Group and Laboratory for Energy Applications for the Future, Lawrence Livermore National Laboratory, Livermore, California 94551, United States
| | - Zuzanna S Siwy
- Department of Chemistry, University of California, Irvine, California 92697, United States
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25
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Role of the Counterions in the Surface Tension of Aqueous Surfactant Solutions. A Computer Simulation Study of Alkali Dodecyl Sulfate Systems. COLLOIDS AND INTERFACES 2020. [DOI: 10.3390/colloids4020015] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have investigated the surface tension contributions of the counterions, surfactant headgroups and tails, and water molecules in aqueous alkali dodecyl sulfate (DS) solutions close to the saturated surface concentration by analyzing the lateral pressure profile contribution of these components using molecular dynamics simulations. For this purpose, we have used the combination of two popular force fields, namely KBFF for the counterions and GROMOS96 for the surfactant, which are both parameterized for the SPC/E water model. Except for the system containing Na+ counterions, the surface tension of the surfactant solutions has turned out to be larger rather than smaller than that of neat water, showing a severe shortcoming of the combination of the two force fields. We have traced back this failure of the potential model combination to the unphysically strong attraction of the KBFF counterions, except for Na+, to the anionic head of the surfactants. Despite this failure of the model, we have observed a clear relation between the soft/hard character (in the sense of the Hofmeister series) and the surface tension contribution of the counterions, which, given the above limitations of the model, can only be regarded as an indicative result. We emphasize that the obtained results, although in a twisted way, clearly stress the crucial role the counterions of ionic surfactants play in determining the surface tension of the aqueous surfactant solutions.
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26
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Peng M, Nguyen AV. Adsorption of ionic surfactants at the air-water interface: The gap between theory and experiment. Adv Colloid Interface Sci 2020; 275:102052. [PMID: 31753297 DOI: 10.1016/j.cis.2019.102052] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Accepted: 10/21/2019] [Indexed: 10/25/2022]
Abstract
We review the experimental and theoretical results for the adsorption and structure of ionic surfactants at the air-liquid interface. The results show that ionic surfactants form thick adsorption layers at the interfacial region. We also review several adsorption models for ionic surfactants, which become increasingly complex as they capture the many features of adsorption layers. However, the adsorption layer structures determined by experiments and the structures predicted by models do not match because most models assume very thin adsorption layers. We show the discrepancies between measured and predicted surface properties and provide several explanations. We conclude that the mismatch in the adsorption layer structure provided by experiments and the structure provided by adsorption models is the main reason for the discrepancies in the surface excess and the surface potential.
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27
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Francisco OA, Clark CJ, Glor HM, Khajehpour M. Do soft anions promote protein denaturation through binding interactions? A case study using ribonuclease A. RSC Adv 2019; 9:3416-3428. [PMID: 35518962 PMCID: PMC9060304 DOI: 10.1039/c8ra10303h] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 01/20/2019] [Indexed: 11/21/2022] Open
Abstract
It has long been known that large soft anions like bromide, iodide and thiocyanate are protein denaturing agents, but their mechanism of action is still unclear. In this work we have investigated the protein denaturing properties of these anions using Ribonuclease A (RNase A) as a model protein system. Salt-induced perturbations to the protein folding free energy were determined using differential scanning calorimetry and the results demonstrate that the addition of sodium iodide and sodium thiocyanate significantly decreases the melting temperature of the protein. In order to account for this reduction in protein stability, we show that the introduction of salts that contain soft anions to the aqueous solvent perturbs the protein unfolding free energy through three mechanisms: (a) screening Coulomb interactions that exist between charged protein residues, (b) Hofmeister effects, and (c) specific anion binding to CH and CH2 moieties in the protein polypeptide backbone. Using the micellization of 1,2-hexanediol as a ruler for hydrophobicity, we have devised a practical methodology that separates the Coulomb and Hofmeister contributions of salts to the protein unfolding free energy. This allowing us to isolate the contribution of soft anion binding interactions to the unfolding process. The analysis shows that binding contributions have the largest magnitude, confirming that it is the binding of soft anions to the polypeptide backbone that is the main promoter of protein unfolding.
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Affiliation(s)
| | | | - Hayden M Glor
- Department of Chemistry, University of Manitoba Canada
| | - Mazdak Khajehpour
- Department of Chemistry, University of Manitoba Canada
- University of Manitoba 468 Parker Bldg. Winnipeg Manitoba R3T2N2 Canada +1-204-2721546
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Dušeková E, Garajová K, Yavaşer R, Varhač R, Sedlák E. Hofmeister effect on catalytic properties of chymotrypsin is substrate-dependent. Biophys Chem 2018; 243:8-16. [DOI: 10.1016/j.bpc.2018.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 09/30/2018] [Accepted: 10/09/2018] [Indexed: 12/26/2022]
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29
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Škvára J, Nezbeda I. Surface of aqueous solutions of alkali halides: layer by layer analysis. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1540871] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Jiří Škvára
- Faculty of Science, J. E. Purkinje University, Ústí nad Labem, Czech Republic
| | - Ivo Nezbeda
- Faculty of Science, J. E. Purkinje University, Ústí nad Labem, Czech Republic
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30
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Cox SJ, Geissler PL. Interfacial ion solvation: Obtaining the thermodynamic limit from molecular simulations. J Chem Phys 2018; 148:222823. [DOI: 10.1063/1.5020563] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Affiliation(s)
- Stephen J. Cox
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Phillip L. Geissler
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, California 94720, USA
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31
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D'Oronzo E, Secundo F, Minofar B, Kulik N, Pometun AA, Tishkov VI. Activation/Inactivation Role of Ionic Liquids on Formate Dehydrogenase fromPseudomonassp. 101 and Its Mutated Thermostable Form. ChemCatChem 2018. [DOI: 10.1002/cctc.201800145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Erica D'Oronzo
- Istituto di Chimica del Riconoscimento Molecolare, CNR; Via Mario Bianco 9 20131 Milan Italy
| | - Francesco Secundo
- Istituto di Chimica del Riconoscimento Molecolare, CNR; Via Mario Bianco 9 20131 Milan Italy
| | - Babak Minofar
- Institute of Microbiology; Academy of, Sciences of the Czech Republic; Zamek 136 37333 Nove Hrady Czech Republic
- Faculty of Science; University of South Bohemia; Branišovská 1760 37005 České Budějovice Czech Republic
| | - Natallia Kulik
- Institute of Microbiology; Academy of, Sciences of the Czech Republic; Zamek 136 37333 Nove Hrady Czech Republic
| | - Anastasia A. Pometun
- Innovations and High Technologies MSU Ltd.; Tsymlyanskaya ul., 16-96 109451 Moscow Russian Federation
- A.N. Bach Institute of Biochemistry; Research Center, of Biotechnology of the Russian Academy of Sciences; bld. 2 Leninsky Ave. Moscow 119071 Russian Federation
| | - Vladimir I. Tishkov
- Innovations and High Technologies MSU Ltd.; Tsymlyanskaya ul., 16-96 109451 Moscow Russian Federation
- Chemistry Faculty; M.V. Lomonosov Moscow State University; Leninskie Gory 1-3 119991 Moscow Russian Federation
- A.N. Bach Institute of Biochemistry; Research Center, of Biotechnology of the Russian Academy of Sciences; bld. 2 Leninsky Ave. Moscow 119071 Russian Federation
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32
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Eberle A, Markert T, Trixler F. Revealing the Physicochemical Basis of Organic Solid–Solid Wetting Deposition: Casimir-like Forces, Hydrophobic Collapse, and the Role of the Zeta Potential. J Am Chem Soc 2018; 140:1327-1336. [DOI: 10.1021/jacs.7b10282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexander Eberle
- Department
of Earth and Environmental Sciences and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Theresienstraße 41, 80333 München, Germany
- Helmholtz Institute Erlangen-Nürnberg for Renewable Energy, Egerlandstr. 3, 91058 Erlangen, Germany
| | - Thomas Markert
- Institute
of Theoretical Chemistry, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany
| | - Frank Trixler
- Department
of Earth and Environmental Sciences and Center for NanoScience (CeNS), Ludwig-Maximilians-Universität München, Theresienstraße 41, 80333 München, Germany
- TUM
School of Education, Technical University of Munich and Deutsches Museum, Museumsinsel 1, 80538 München, Germany
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33
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Kiani S, Taherkhani F. Free energy, configurational and nonextensivity of Tsallis entropy with the size and temperature in colloidal silver nanoparticles in [EMim][PF6] ionic liquid. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.11.139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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34
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Howard RJ, Carnevale V, Delemotte L, Hellmich UA, Rothberg BS. Permeating disciplines: Overcoming barriers between molecular simulations and classical structure-function approaches in biological ion transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:927-942. [PMID: 29258839 DOI: 10.1016/j.bbamem.2017.12.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 12/08/2017] [Accepted: 12/14/2017] [Indexed: 11/20/2022]
Abstract
Ion translocation across biological barriers is a fundamental requirement for life. In many cases, controlling this process-for example with neuroactive drugs-demands an understanding of rapid and reversible structural changes in membrane-embedded proteins, including ion channels and transporters. Classical approaches to electrophysiology and structural biology have provided valuable insights into several such proteins over macroscopic, often discontinuous scales of space and time. Integrating these observations into meaningful mechanistic models now relies increasingly on computational methods, particularly molecular dynamics simulations, while surfacing important challenges in data management and conceptual alignment. Here, we seek to provide contemporary context, concrete examples, and a look to the future for bridging disciplinary gaps in biological ion transport. This article is part of a Special Issue entitled: Beyond the Structure-Function Horizon of Membrane Proteins edited by Ute Hellmich, Rupak Doshi and Benjamin McIlwain.
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Affiliation(s)
- Rebecca J Howard
- Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, Box 1031, 17121 Solna, Sweden.
| | - Vincenzo Carnevale
- Institute for Computational Molecular Science, Department of Chemistry, Temple University, Philadelphia, PA 19122, USA.
| | - Lucie Delemotte
- Science for Life Laboratory, Department of Theoretical Physics, KTH Royal Institute of Technology, Box 1031, 17121 Solna, Sweden.
| | - Ute A Hellmich
- Johannes Gutenberg University Mainz, Institute for Pharmacy and Biochemistry, Johann-Joachim-Becherweg 30, 55128 Mainz, Germany; Centre for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue Str. 9, 60438 Frankfurt, Germany.
| | - Brad S Rothberg
- Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA.
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35
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Wick CD. A comparison of sodium and hydrogen halides at the air-water interface. J Chem Phys 2017; 147:161703. [PMID: 29096503 PMCID: PMC5648577 DOI: 10.1063/1.4984114] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 05/12/2017] [Indexed: 11/14/2022] Open
Abstract
New molecular models, parameterized to ab initio calculations, were developed to describe HBr and HI at the air-water interface. These were used to compare how the air-water interface influenced dissociation of NaX and HX, with X being Cl, Br, or I, and also their propensity for the interface. The polarizable multistate empirical valence bond method, which explicitly describes proton sharing, was used to model HX. Results showed that the air-water interface suppressed HX dissociation from a contact ion pair to a solvent separated to a greater degree than NaX dissociation. Furthermore, HX had a greater propensity for the interface than NaX, which was a consequence of the hydronium ion having a greatest interfacial activity of all species studied. As a consequence of this, the average configuration of dissociated HX, while in both contact ion and solvent separated ion pairs near the air-water interface, is with the dissociated hydrogen oriented more towards the air than the X atom.
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Affiliation(s)
- Collin D Wick
- Louisiana Tech University, Ruston, Louisiana 71270, USA
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36
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Sung W, Avazbaeva Z, Kim D. Salt Promotes Protonation of Amine Groups at Air/Water Interface. J Phys Chem Lett 2017; 8:3601-3606. [PMID: 28722420 DOI: 10.1021/acs.jpclett.7b01198] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Interfacial water reorientation caused by charged Langmuir monolayers consisting of primary fatty amine (ODA) and cationic lipid having quaternary amine headgroup (DPTAP) were investigated by interface-selective vibrational sum-frequency generation spectroscopy. For DPTAP monolayer, initially large sum-frequency intensity from interfacial water OH band decreased steadily by increasing monovalent salt (NaCl, NaI) concentration due to counterion adsorption. On the other hand, ODA/water exhibited significantly smaller sum-frequency intensity than DPTAP/water, implying only small portion of protonated amine group (-NH3+) initially existed. By increasing the ionic strength, however, SF intensity of water OH band was enhanced markedly up to ∼1 mM, and then decreased in both NaCl and NaI solutions. By measuring the phase of the sum-frequency spectra, it was found that water dipoles under the ODA headgroup point downward, indicating that the surfaces were always positively charged. This demonstrated that increasing ionic strength facilitates protonation of primary amine headgroups. A simple model based on Poisson-Boltzmann (PB) theory explained this protonation behavior of primary amines.
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Affiliation(s)
- Woongmo Sung
- Department of Physics, Sogang University , Seoul 04107, Korea
| | - Zaure Avazbaeva
- Department of Physics, Sogang University , Seoul 04107, Korea
| | - Doseok Kim
- Department of Physics, Sogang University , Seoul 04107, Korea
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Trotochaud L, Head AR, Karslıoğlu O, Kyhl L, Bluhm H. Ambient pressure photoelectron spectroscopy: Practical considerations and experimental frontiers. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:053002. [PMID: 27911885 DOI: 10.1088/1361-648x/29/5/053002] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Over the past several decades, ambient pressure x-ray photoelectron spectroscopy (APXPS) has emerged as a powerful technique for in situ and operando investigations of chemical reactions under relevant ambient atmospheres far from ultra-high vacuum conditions. This review focuses on exemplary cases of APXPS experiments, giving special consideration to experimental techniques, challenges, and limitations specific to distinct condensed matter interfaces. We discuss APXPS experiments on solid/vapor interfaces, including the special case of 2D films of graphene and hexagonal boron nitride on metal substrates with intercalated gas molecules, liquid/vapor interfaces, and liquid/solid interfaces, which are a relatively new class of interfaces being probed by APXPS. We also provide a critical evaluation of the persistent limitations and challenges of APXPS, as well as the current experimental frontiers.
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Affiliation(s)
- Lena Trotochaud
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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38
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Ganesan SJ, Xu H, Matysiak S. Influence of Monovalent Cation Size on Nanodomain Formation in Anionic–Zwitterionic Mixed Bilayers. J Phys Chem B 2017; 121:787-799. [DOI: 10.1021/acs.jpcb.6b10099] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sai J. Ganesan
- Fischell
Department of Bioengineering and ‡Biophysics Program, Institute of
Physical Science and Technology, University of Maryland, College
Park, Maryland 20742, United States
| | - Hongcheng Xu
- Fischell
Department of Bioengineering and ‡Biophysics Program, Institute of
Physical Science and Technology, University of Maryland, College
Park, Maryland 20742, United States
| | - Silvina Matysiak
- Fischell
Department of Bioengineering and ‡Biophysics Program, Institute of
Physical Science and Technology, University of Maryland, College
Park, Maryland 20742, United States
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39
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Sung W, Kim D. Observation of isolated ionic liquid cations and water molecules in an inert solvent. Phys Chem Chem Phys 2016; 18:27529-27535. [PMID: 27711686 DOI: 10.1039/c6cp05292d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
1-Octyl-3-methyl imidazolium halides ([OMIM]I and [OMIM]Cl) were loaded on top of CCl4, and an in situ inclusion process was monitored from the CCl4 phase as time elapses by infrared absorption spectroscopy. Absorption from the bands corresponding to the C(2)-H and C(4,5)-H stretch modes in the imidazolium cation was reduced significantly compared to the bulk IL spectra. This indicates that (1) the [OMIM] cation exists in CCl4 as a monomer, dissociated from the anion and other cations, and (2) hydrogen bonding between the anion and the cation increases the dipole strength of the CH moieties in the imidazolium ring. [OMIM]I was found to transfer into the CCl4 phase much faster than [OMIM]Cl, and this instigated us to compare the transfer of aqueous solutions of ionic liquids, 1-butyl-3-methyl imidazolium halides ([BMIM]I and [BMIM]Cl) into the CCl4 matrix. Not only [BMIM]I but also water molecules transferred faster compared to those in the [BMIM]Cl aqueous solution. Water molecules in CCl4 were shown to form clusters in [BMIM]I; presumably, I- anions work as nucleation centers of water clusters.
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Affiliation(s)
- Woongmo Sung
- Department of Physics, Sogang University, Seoul 121-742, Korea.
| | - Doseok Kim
- Department of Physics, Sogang University, Seoul 121-742, Korea.
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41
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Marcus Y. Specific ion effects on the surface tension and surface potential of aqueous electrolytes. Curr Opin Colloid Interface Sci 2016. [DOI: 10.1016/j.cocis.2016.06.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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42
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Santos DP, Longo RL. Molecular Dynamics Simulations of Specific Anion Adsorption on Sulfobetaine (SB3-14) Micelles. J Phys Chem B 2016; 120:2771-80. [DOI: 10.1021/acs.jpcb.5b12475] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Diego P. Santos
- Departamento
de Química
Fundamental, Universidade Federal de Pernambuco, 50.740-560 Recife, PE, Brazil
| | - Ricardo L. Longo
- Departamento
de Química
Fundamental, Universidade Federal de Pernambuco, 50.740-560 Recife, PE, Brazil
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43
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TANG YING, LI HANG, ZHU HUALING, TIAN RUI, GAO XIAODAN. Impact of electric field on Hofmeister effects in aggregation of negatively charged colloidal minerals. J CHEM SCI 2016. [DOI: 10.1007/s12039-015-1008-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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44
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Benay G, Wipff G. Liquid–liquid extraction of alkali cations by 18-crown-6: complexation and interface crossing studied by MD and PMF simulations. NEW J CHEM 2016. [DOI: 10.1039/c5nj02609a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 18C6/M+Pic−complexes form and adsorb “right at the nano-interface” where 18C6 prefers the K+guest.
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Affiliation(s)
- Gael Benay
- Laboratoire MSM
- UMR 7140
- Institut de Chimie
- 67000 Strasbourg
- France
| | - Georges Wipff
- Laboratoire MSM
- UMR 7140
- Institut de Chimie
- 67000 Strasbourg
- France
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45
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Zeng X, Zhang Y, Xia Z, Wang L, Wang C, Huang Y, Shen R, Wen W. Surface evolution of manganese chloride aqueous droplets resulting in self-suppressed evaporation. Sci Rep 2015; 5:13322. [PMID: 26292669 PMCID: PMC4544006 DOI: 10.1038/srep13322] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 07/21/2015] [Indexed: 11/25/2022] Open
Abstract
The exchange kinetics of liquid water, which are of fundamental interest and have potential applications, remain unclear. A fantastic and extraordinary phenomenon was observed during the evaporation of a water droplet doped with manganese chloride. As observed from the evolution of this type of droplet, a thin film was formed on the surface with an exothermic phase transition, resulting in self-suppressed evaporation. The MnCl2-doped water droplets were maintained in a relative humidity (RH) of 50% at 40 °C for more than a week and for longer than two months at a temperature of 25 °C. In contrast, a pure water droplet can only be sustained for a few minutes. The self-suppressed evaporation of doped water may be due to the special hydration of the accumulated manganese and chloride ions at the surface, decreasing the surface tension.
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Affiliation(s)
- Xiping Zeng
- Nano Science and Technology Program / Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Yifan Zhang
- Institute of Chemistry, the Chinese Academy of Sciences, Zhongguancun North 1st St, Haidian, Beijing, China
| | - Zengzilu Xia
- Nano Science and Technology Program / Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Li Wang
- Nano Science and Technology Program / Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Cong Wang
- Nano Science and Technology Program / Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | - Yingzhou Huang
- Chongqing University, No. 174 Shazhengjie, Shapingba, Chongqing, 400044, China
| | - Rong Shen
- Institute of Physics, Chinese Academy of Sciences, Haidian, Beijing, China
| | - Weijia Wen
- Nano Science and Technology Program / Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
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Elk JC, Benjamin I. β-Cyclodextrin at the Water/1-Bromobutane Interface: Molecular Insight into Reverse Phase Transfer Catalysis. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:5086-5092. [PMID: 25909764 DOI: 10.1021/acs.langmuir.5b01025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Molecular insight into the role of β-cyclodextrin (βCD) as a phase transfer catalyst at the liquid/liquid interface is obtained by molecular dynamics simulations of the structure and dynamics of βCD adsorbed at the interface between water and 1-bromobutane. In particular, we consider the structure and dynamics of the water and bromobutane molecules inside the βCD cavity and compare them with the behavior when βCD is dissolved in bulk water. βCD is preferentially oriented at the interface, with the cavity opening along the interface normal. While in bulk water the cavity includes 6-8 water molecules that are relatively mobile with short residence time, at the interface the cavity is mostly dehydrated and includes a single bromobutane molecule. This inclusion complex is stable in bulk water. The implication of this behavior for reverse phase transfer catalysis is discussed.
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Affiliation(s)
- Jackson Chief Elk
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
| | - Ilan Benjamin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, Santa Cruz, California 95064, United States
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48
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Benjamin I. Correlating structure and thermodynamics of hydrophobic–hydrophilic ion pairs in water. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.02.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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49
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50
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Benay G, Wipff G. Ammonium Recognition by 18-Crown-6 in Different Solutions and at an Aqueous Interface: A Simulation Study. J Phys Chem B 2014; 118:13913-29. [DOI: 10.1021/jp508379w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- G. Benay
- Laboratoire MSM, UMR 7177, Institut de Chimie, 1 rue B. Pascal, 67000 Strasbourg, France
| | - G. Wipff
- Laboratoire MSM, UMR 7177, Institut de Chimie, 1 rue B. Pascal, 67000 Strasbourg, France
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