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Gregory KP, Elliott GR, Robertson H, Kumar A, Wanless EJ, Webber GB, Craig VSJ, Andersson GG, Page AJ. Understanding specific ion effects and the Hofmeister series. Phys Chem Chem Phys 2022; 24:12682-12718. [PMID: 35543205 DOI: 10.1039/d2cp00847e] [Citation(s) in RCA: 87] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Specific ion effects (SIE), encompassing the Hofmeister Series, have been known for more than 130 years since Hofmeister and Lewith's foundational work. SIEs are ubiquitous and are observed across the medical, biological, chemical and industrial sciences. Nevertheless, no general predictive theory has yet been able to explain ion specificity across these fields; it remains impossible to predict when, how, and to what magnitude, a SIE will be observed. In part, this is due to the complexity of real systems in which ions, counterions, solvents and cosolutes all play varying roles, which give rise to anomalies and reversals in anticipated SIEs. Herein we review the historical explanations for SIE in water and the key ion properties that have been attributed to them. Systems where the Hofmeister series is perturbed or reversed are explored, as is the behaviour of ions at the liquid-vapour interface. We discuss SIEs in mixed electrolytes, nonaqueous solvents, and in highly concentrated electrolyte solutions - exciting frontiers in this field with particular relevance to biological and electrochemical applications. We conclude the perspective by summarising the challenges and opportunities facing this SIE research that highlight potential pathways towards a general predictive theory of SIE.
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Affiliation(s)
- Kasimir P Gregory
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia. .,Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Gareth R Elliott
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Hayden Robertson
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Anand Kumar
- Flinders Institute of Nanoscale Science and Technology, College of Science and Engineering, Flinders University, South Australia 5001, Australia
| | - Erica J Wanless
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
| | - Grant B Webber
- School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Vincent S J Craig
- Department of Materials Physics, Research School of Physics, Australian National University, Canberra, ACT 0200, Australia
| | - Gunther G Andersson
- Flinders Institute of Nanoscale Science and Technology, College of Science and Engineering, Flinders University, South Australia 5001, Australia
| | - Alister J Page
- Discipline of Chemistry, School of Environmental and Life Sciences, The University of Newcastle, Callaghan, New South Wales 2308, Australia.
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2
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Kumar A, Craig VS, Page AJ, Webber GB, Wanless EJ, Andersson G. Ion Specificity in the Measured Concentration Depth Profile of Ions at the Vapor-Glycerol Interface. J Colloid Interface Sci 2022; 626:687-699. [DOI: 10.1016/j.jcis.2022.06.104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/04/2022] [Accepted: 06/21/2022] [Indexed: 10/31/2022]
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Abstract
Why the bubbles are negatively charged? This is almost 100 years old question, which many scientists have striven and still are striving to answer using the latest developments of the MD simulations and various physical analytical methods. We scrutinize with this paper the basic literature on this topic and conduct our own analysis. Following the philosophical law of parsimony: “Entities should not be multiplied without necessity”, we assume that the simplest explanation is the right one. It is well known that the negative change of the Gibbs free energy is a solid criterion for spontaneous process. Hence, we calculated the energies of adsorption of OH−, H3O+ and HCO3− ions on the air/water interface using the latest theoretical developments on the dispersion interaction of inorganic ions with the air/water interface. Thus, we established that the adsorption of OH− and HCO3− ions is energetically favorable, while the adsorption of H3O+ is energetically unfavorable. Moreover, we calculated the change of the entropy of these ions upon their transfer from the bulk to the air/water interface. Using the well-known formula ΔG = ΔH − TΔS, we established that the adsorption of OH− and HCO3− ions on the air/water interface decreases their Gibbs free energy. On the contrary, the adsorption of H3O+ ions on the air/water interface increases their Gibbs free energy. Thus, we established that both OH− and HCO3− ions adsorb on the air/water interface, while the H3O+ ions are repelled by the latter. Therefore, electrical double layer (EDL) is formed at the surface of the bubble–negatively charged adsorption layer of OH− and HCO3− ions and positively charged diffuse layer of H3O+ ions.
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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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5
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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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6
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Zdarta A, Pacholak A, Smułek W, Zgoła-Grześkowiak A, Ferlin N, Bil A, Kovensky J, Grand E, Kaczorek E. Biological impact of octyl d-glucopyranoside based surfactants. CHEMOSPHERE 2019; 217:567-575. [PMID: 30447608 DOI: 10.1016/j.chemosphere.2018.11.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/27/2018] [Accepted: 11/02/2018] [Indexed: 06/09/2023]
Abstract
Development of many branches of industry has stimulated the search for new, effective surfactants with interesting properties. Potential use of alkyl glucose derivatives on a large scale, raises questions about the possible risks associated with their entry into the natural environment. To be able to evaluate this risk, the aim of the study was to determine the physicochemical properties of octyl d-glucopyranoside and its three derivatives: N-(octyl d-glucopyranosiduronyl)aspartic acid, N-(octyl d-glucopyranosiduronyl)glicyne and octyl d-glucopyranosiduronic acid. Moreover, their biodegradability by pure bacterial strains and biocenosis present in river water was examined. While descriptions of sugar-based surfactants on microbial cells are limited, the essential element of the study was to determine the effect of surfactants on cell surface properties of microorganisms isolated from activated sludge and compare it to the effects of the petroleum based surfactants and the surfactants produced from renewable materials. The results obtained indicate that physicochemical properties of surface active agents differ depending on the presence of functional groups in the surfactants molecules. What is more, the presence of amino acid substituent in the derivatives of octyl d-glucopyranoside resulted in a slight decrease in the surfactants biodegradation efficiency, in comparison to the compounds that did not contain such a substituent, prolonging this process from 5 to 10 days. Interestingly, even relatively slightly different derivatives modified the cell surface properties in a different way. Importantly, the surfactants based on octyl d-glucopyranoside have less negative impact on environmental microorganism and better biodegradability than the surfactant synthesized from petroleum products.
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Affiliation(s)
- Agata Zdarta
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Amanda Pacholak
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Wojciech Smułek
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland.
| | - Agnieszka Zgoła-Grześkowiak
- Institute of Chemistry and Technical Electrochemistry, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
| | - Nadège Ferlin
- Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources (LG2A), CNRS UMR 7378, Institut de Chimie de Picardie CNRS FR 3085, Université de Picardie Jules Verne, Amiens Cedex, France
| | - Abed Bil
- Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources (LG2A), CNRS UMR 7378, Institut de Chimie de Picardie CNRS FR 3085, Université de Picardie Jules Verne, Amiens Cedex, France
| | - José Kovensky
- Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources (LG2A), CNRS UMR 7378, Institut de Chimie de Picardie CNRS FR 3085, Université de Picardie Jules Verne, Amiens Cedex, France
| | - Eric Grand
- Laboratoire de Glycochimie, des Antimicrobiens et des Agroressources (LG2A), CNRS UMR 7378, Institut de Chimie de Picardie CNRS FR 3085, Université de Picardie Jules Verne, Amiens Cedex, France.
| | - Ewa Kaczorek
- Institute of Chemical Technology and Engineering, Poznan University of Technology, Berdychowo 4, 60-965 Poznan, Poland
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Artiglia L, Edebeli J, Orlando F, Chen S, Lee MT, Corral Arroyo P, Gilgen A, Bartels-Rausch T, Kleibert A, Vazdar M, Andres Carignano M, Francisco JS, Shepson PB, Gladich I, Ammann M. A surface-stabilized ozonide triggers bromide oxidation at the aqueous solution-vapour interface. Nat Commun 2017; 8:700. [PMID: 28951540 PMCID: PMC5615067 DOI: 10.1038/s41467-017-00823-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 07/26/2017] [Indexed: 12/02/2022] Open
Abstract
Oxidation of bromide in aqueous environments initiates the formation of molecular halogen compounds, which is important for the global tropospheric ozone budget. In the aqueous bulk, oxidation of bromide by ozone involves a [Br•OOO−] complex as intermediate. Here we report liquid jet X-ray photoelectron spectroscopy measurements that provide direct experimental evidence for the ozonide and establish its propensity for the solution-vapour interface. Theoretical calculations support these findings, showing that water stabilizes the ozonide and lowers the energy of the transition state at neutral pH. Kinetic experiments confirm the dominance of the heterogeneous oxidation route established by this precursor at low, atmospherically relevant ozone concentrations. Taken together, our results provide a strong case of different reaction kinetics and mechanisms of reactions occurring at the aqueous phase-vapour interface compared with the bulk aqueous phase. Heterogeneous oxidation of bromide in atmospheric aqueous environments has long been suspected to be accelerated at the interface between aqueous solution and air. Here, the authors provide spectroscopic, kinetic and theoretical evidence for a rate limiting, surface active ozonide formed at the interface.
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Affiliation(s)
- Luca Artiglia
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Laboratory for Catalysis and Sustainable Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Jacinta Edebeli
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Institute of Atmospheric and Climate Sciences, ETH Zürich, 8092, Zürich, Switzerland
| | - Fabrizio Orlando
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Shuzhen Chen
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Institute of Atmospheric and Climate Sciences, ETH Zürich, 8092, Zürich, Switzerland
| | - Ming-Tao Lee
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Chemical Physics Division, Department of Physics, Stockholm University, 10691, Stockholm, Sweden
| | - Pablo Corral Arroyo
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Department of Chemistry and Biochemistry, University of Bern, 3012, Bern, Switzerland
| | - Anina Gilgen
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland.,Institute of Atmospheric and Climate Sciences, ETH Zürich, 8092, Zürich, Switzerland
| | | | - Armin Kleibert
- Swiss Light Source, Paul Scherrer Institut, 5232, Villigen, Switzerland
| | - Mario Vazdar
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, Bijenička 54, 10000, Zagreb, Croatia
| | - Marcelo Andres Carignano
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 34110, Doha, Qatar
| | - Joseph S Francisco
- Department of Chemistry, University of Nebraska-Lincoln, 433 Hamilton Hall, Lincoln, NE, 68588-0304, USA
| | - Paul B Shepson
- Department of Chemistry, and Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, IN, 46097, USA
| | - Ivan Gladich
- Qatar Environment and Energy Research Institute, Hamad Bin Khalifa University, P.O. Box 34110, Doha, Qatar.
| | - Markus Ammann
- Laboratory of Environmental Chemistry, Paul Scherrer Institut, 5232, Villigen, Switzerland.
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9
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Tissot H, Gallet JJ, Bournel F, Olivieri G, Silly MG, Sirotti F, Boucly A, Rochet F. The Electronic Structure of Saturated NaCl and NaI Solutions in Contact with a Gold Substrate. Top Catal 2015. [DOI: 10.1007/s11244-015-0530-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Ridings C, Andersson GG. Change of Surface Structure upon Foam Film Formation. Chemphyschem 2015; 16:733-8. [DOI: 10.1002/cphc.201402821] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Indexed: 11/09/2022]
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11
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Andersson G, Ridings C. Ion Scattering Studies of Molecular Structure at Liquid Surfaces with Applications in Industrial and Biological Systems. Chem Rev 2014; 114:8361-87. [DOI: 10.1021/cr400417f] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- Gunther Andersson
- Centre
for NanoScale Science
and Technology, Flinders University, Adelaide, South Australia 5001, Australia
| | - Christiaan Ridings
- Centre
for NanoScale Science
and Technology, Flinders University, Adelaide, South Australia 5001, Australia
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12
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Dang LX, Sun X, Ginovska-Pangovska B, Annapureddy HVR, Truong TB. Understanding ion-ion interactions in bulk and aqueous interfaces using molecular simulations. Faraday Discuss 2013; 160:151-60; discussion 207-24. [PMID: 23795498 DOI: 10.1039/c2fd20093g] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In addition to its scientific significance, the distribution of ions in the bulk and at aqueous interfaces is also very important for practical reasons. Providing a quantitative description of the ionic distribution, and describing interactions between ions in different environments, remains a challenge, and is the subject of current debate. In this study, we found that interionic potentials of mean force (PMFs) and interfacial properties are very sensitive to the ion-ion interaction potential models. Our study predicted a Sr(2+)--CI- PMF with no contact ion-pair state and a shallow solvent-separated ion-pair state. In addition, we were able to quantitatively capture the experimental X-ray reflectivity results of the aqueous salt interface of the Sr(2+)--Cl- ion-pair, and provided a detailed physical description of the interfacial structure for this system. We also predicted the Xray reflectivity results for SrBr2 and SrI2 systems.
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Affiliation(s)
- Liem X Dang
- Chemical and Materials Sciences Division, Pacific Northwest National Laboratory, Richland, WA4 93352, USA.
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14
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Do hydration forces play a role in thin film drainage and rupture observed in electrolyte solutions? Curr Opin Colloid Interface Sci 2011. [DOI: 10.1016/j.cocis.2011.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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15
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Sun X, Wick CD, Dang LX. Computational Study of Ion Distributions at the Air/Liquid Methanol Interface. J Phys Chem A 2010; 115:5767-73. [DOI: 10.1021/jp107563e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Xiuquan Sun
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
| | - Collin D. Wick
- Louisiana Tech University, Ruston, Louisiana 71270, United States
| | - Liem X. Dang
- Pacific Northwest National Laboratory, Richland, Washington 99352, United States
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16
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Abstract
For a decade, it has been discussed whether or not inorganic ions like iodide or bromide adsorb preferentially at liquid surfaces. Thermodynamic relationships cannot be used to derive detailed information about the molecular structure of surfaces. Thus, it is import to investigate the structure of liquid surfaces directly. Neutral Impact Collision Ion Scattering Spectroscopy is one of the very few techniques that can be used to determine directly the molecular structure of liquid surfaces.
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17
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Jungwirth P. Spiers Memorial Lecture. Ions at aqueous interfaces. Faraday Discuss 2009; 141:9-30; discussion 81-98. [PMID: 19227348 DOI: 10.1039/b816684f] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Studies of aqueous interfaces and of the behavior of ions therein have been profiting from a recent remarkable progress in surface selective spectroscopies, as well as from developments in molecular simulations. Here, we summarize and place in context our investigations of ions at aqueous interfaces employing molecular dynamics simulations and electronic structure methods, performed in close contact with experiment. For the simplest of these interfaces, i.e. the open water surface, we demonstrate that the traditional picture of an ion-free surface is not valid for large, soft (polarizable) ions such as the heavier halides. Both simulations and spectroscopic measurements indicate that these ions can be present and even enhanced at surface of water. In addition we show that the ionic product of water exhibits a peculiar surface behavior with hydronium but not hydroxide accumulating at the air/water and alkane/water interfaces. This result is supported by surface-selective spectroscopic experiments and surface tension measurements. However, it contradicts the interpretation of electrophoretic and titration experiments in terms of strong surface adsorption of hydroxide; an issue which is further discussed here. The applicability of the observed behavior of ions at the water surface to investigations of their affinity for the interface between proteins and aqueous solutions is explored. Simulations show that for alkali cations the dominant mechanism of specific interactions with the surface of hydrated proteins is via ion pairing with negatively charged amino acid residues and with the backbone amide groups. As far as halide anions are concerned, the lighter ones tend to pair with positively charged amino acid residues, while heavier halides exhibit affinity to the amide group and to non-polar protein patches, the latter resembling their behavior at the air/water interface. These findings, together with results for more complex molecular ions, allow us to formulate a local model of interactions of ions with proteins with the aim to rationalize at the molecular level ion-specific Hofmeister effects, e.g. the salting out of proteins.
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Affiliation(s)
- Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Complex Molecular Systems and Biomolecules, Prague, Czech Republic.
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Bell RC, Wu K, Iedema MJ, Schenter GK, Cowin JP. The oil-water interface: mapping the solvation potential. J Am Chem Soc 2009; 131:1037-42. [PMID: 19154174 DOI: 10.1021/ja805962x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
An ion moving across an oil-water interface experiences strong solvation changes. We have directly measured the solvation potential from 0.4 to 4 nm for Cs(+) ions approaching the oil-water interface from the oil side ("oil" = 3-methylpentane). The interfaces were built at 30 K using molecular beam epitaxy. Ions were precisely placed within the film during its growth using a soft-landing ion beam. The ion's collective electric field was progressively increased (by adding more ions) until it balanced the individual ion's solvation potential slope. As the samples were slowly warmed, near 90 K the ions began moving, as measured by a Kelvin probe. Their motion precisely determines the local slope of the solvation potential, which was integrated to get the potential. The potential is Born-like for z > 0.4 nm away from the oil-water interface. Our method could provide important tests of theoretical estimates of ion motion at biological interfaces and in atmospheric aerosols.
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Affiliation(s)
- Richard C Bell
- Chemistry Department, The Pennsylvania State University, Altoona College, Altoona, Pennsylvania 16601, USA
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19
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Henry CL, Craig VSJ. Ion-specific influence of electrolytes on bubble coalescence in nonaqueous solvents. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:7979-7985. [PMID: 18598065 DOI: 10.1021/la8008738] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We report the effects of electrolytes on bubble coalescence in nonaqueous solvents methanol, formamide, propylene carbonate, and dimethylsulfoxide (DMSO). Results in these solvents are compared to the ion-specific bubble coalescence inhibition observed in aqueous electrolyte solutions, which is predicted by simple, empirical ion combining rules. Coalescence inhibition by electrolytes is observed in all solvents, at a lower concentration range (0.01 M to 0.1M) to that observed in water. Formamide shows ion-specific salt effects dependent upon ion combinations in a way analogous to the combining rules observed in water. Bubble coalescence in propylene carbonate is also consistent with ion-combining rules, but the ion assignments differ to those for water. In both methanol and DMSO all salts used are found to inhibit bubble coalescence. Our results show that electrolytes influence bubble coalescence in a rich and complex way, but with notable similarities across all solvents tested. Coalescence is influenced by the drainage of fluid between two bubbles to form a film and then the rupture of the film and one might expect that these processes will vary dramatically between solvents. The similarities in behavior we observe show that coalescence inhibition is unlikely to be related to the surface forces present but is perhaps related to the dynamic thinning and rupture of the liquid film through the hydrodynamic boundary condition.
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Affiliation(s)
- Christine L Henry
- Department of Applied Mathematics, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200 Australia
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Affiliation(s)
- Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Complex Molecular Systems and Biomolecules, 16610 Prague 6, Czech Republic;
| | - Bernd Winter
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, D-12489 Berlin, Germany;
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Bahr S, Toubin C, Kempter V. Interaction of methanol with amorphous solid water. J Chem Phys 2008; 128:134712. [DOI: 10.1063/1.2901970] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Souda R. Roles of Deeply Supercooled Ethanol in Crystallization and Solvation of LiI. J Phys Chem B 2008; 112:2649-54. [DOI: 10.1021/jp710263m] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ryutaro Souda
- Nanoscale Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
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23
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Souda R, Günster J. Temperature-programed time-of-flight secondary ion mass spectrometry study of 1-butyl-3-methylimidazolium trifluoromethanesulfonate during glass-liquid transition, crystallization, melting, and solvation. J Chem Phys 2008; 129:094707. [DOI: 10.1063/1.2965526] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
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24
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Affiliation(s)
- Philip Ball
- Nature, 4-6 Crinan Street, London N1 9XW, U.K
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25
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Souda R. Interaction of water with LiCl, LiBr, and LiI in the deeply supercooled region. J Chem Phys 2007; 127:214505. [DOI: 10.1063/1.2802299] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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Clifford D, Donaldson DJ. Direct Experimental Evidence for a Heterogeneous Reaction of Ozone with Bromide at the Air−Aqueous Interface. J Phys Chem A 2007; 111:9809-14. [PMID: 17803288 DOI: 10.1021/jp074315d] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recent experimental and theoretical evidence has indicated an enhancement of the heavier halide ions at the air-aqueous interface, relative to their bulk concentrations. This, along with an order of magnitude discrepancy between measured and predicted Br2 production in the reaction of ozone with deliquesced NaBr aerosol, has led to the suggestion that an interface reaction occurs between ozone and bromide. We have used harmine, a beta-carboline alkaloid, as an interface-sensitive fluorescent pH probe in order to measure pH changes associated with the interfacial reaction of ozone and bromide. The rate of pH change depends upon the bulk bromide concentration in a way which is well described by a Langmuir-Hinshelwood kinetic model. In the presence of octanol at the interface, the rate of pH change tracks the octanol adsorption isotherm, as expected if octanol enhances the concentration of ozone at the surface.
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Affiliation(s)
- Daniel Clifford
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
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Souda R. Hydration of NaCl on Glassy, Supercooled-Liquid, and Crystalline Water. J Phys Chem B 2007; 111:11209-13. [PMID: 17760437 DOI: 10.1021/jp0725580] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Interactions of sodium chloride with amorphous and crystalline water films, leading to the possible formation of a dilute NaCl solution, were investigated using time-of-flight secondary ion mass spectrometry as a function of temperature. A monolayer of NaCl tends to remain on the surface or in subsurface sites of thick amorphous solid water films (200 monolayers); the Na+ ion is hydrated preferentially, whereas the Cl- ion is segregated at the surface. The hydration structure of NaCl is fundamentally unchanged for viscous liquid water that appears at temperatures higher than 136 K. The solubility of NaCl increases abruptly at 160 K because of the evolution of supercooled liquid water, which can hydrate the Cl- ion efficiently. However, the diffusion of the ions toward the bulk of supercooled liquid water is interrupted by crystallization; therefore, the dilute NaCl solution that is characterized by completely separated Na+-Cl- pairs may not be formed. When NaCl is deposited on the crystalline ice film, hydration of NaCl is enhanced above 160 K as well, indicating that a liquidlike phase coexists with crystals.
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Affiliation(s)
- Ryutaro Souda
- Nanoscale Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
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Cwiklik L, Andersson G, Dang LX, Jungwirth P. Segregation of Inorganic Ions at Surfaces of Polar Nonaqueous Liquids. Chemphyschem 2007; 8:1457-63. [PMID: 17520587 DOI: 10.1002/cphc.200700039] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
We present a short review of recent computational and experimental studies on surfaces of solutions of inorganic salts in polar nonaqueous solvents. These investigations complement our knowledge of aqueous interfaces and show that liquids such as formamide, liquid ammonia, and ethylene glycol can also surface-segregate large polarizable anions like iodide, albeit less efficiently than water. For liquids whose surfaces are covered with hydrophobic groups (e.g. methanol), the surface-ion effect all but disappears. Based on the present data a general picture of inorganic-ion solvation at the solution-vapor interface of polar liquids is outlined.
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Affiliation(s)
- Lukasz Cwiklik
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic and Center for Biomolecules and Complex Molecular Systems, Flemingovo nám. 2, 16610 Prague 6, Czech Republic
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Höfft O, Bahr S, Himmerlich M, Krischok S, Schaefer JA, Kempter V. Electronic structure of the surface of the ionic liquid [EMIM][Tf(2)N] studied by metastable impact electron spectroscopy (MIES), UPS, and XPS. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:7120-3. [PMID: 16893200 DOI: 10.1021/la060943v] [Citation(s) in RCA: 100] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The near-surface electronic structure of the room-temperature ionic liquid (RT-IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][Tf(2)N]) has been investigated with the combination of the electron spectroscopies metastable impact electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS (HeI and HeII)), and monochromatized X-ray photoelectron spectroscopy (XPS). We find that the top of the valence band states originates from states of the cation (see also ref 1). The ultimately surface-sensitive technique MIES proves that the surface layer consists of both cations and anions. The temperature dependence of the spectra has been measured between about 160 and 610 K. Information on the glass transition and the possibility for low-temperature distillation of [EMIM][Tf(2)N] at reduced pressures is derived from the present results.
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Affiliation(s)
- O Höfft
- Institut für Physik und Physikalische Technologien, Technische Universität Clausthal, Leibnizstr. 4, D-38678 Clausthal-Zellerfeld, Germany
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Höfft O, Kahnert U, Bahr S, Kempter V. Interaction of NaI with Solid Water and Methanol. J Phys Chem B 2006; 110:17115-20. [PMID: 16928006 DOI: 10.1021/jp0626014] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The interaction of NaI with amorphous solid water (ASW) and methanol (MeOH) has been investigated with metastable impact electron spectroscopy (MIES), UPS(HeI), and temperature programmed desorption (TPD). We have studied the electron emission from the ionization of the highest-lying states of H(2)O, CH(3)OH, and of 5pI. We have prepared NaI layers on ASW (MeOH) films at about 105 K and annealed them up to about 200 K. Surface segregation of iodide is observed in ASW, as predicted for NaI aqueous solutions. On the other hand, surface segregation is not observed in MeOH, again as predicted for the interaction of NaI with liquid methanol. Electronic properties (ionization potentials, optical band gaps) and water binding energies are reported and are analyzed on the basis of available DFT results for hydrated NaI clusters.
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Affiliation(s)
- O Höfft
- Technische Universität Clausthal, Institut für Physik und Physikalische Technologien, Leibnizstr. 4, D-38678 Clausthal-Zellerfeld, Germany
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