Solution chemistry effects on the solvation shell of metal ions

<div> As natural aqueous solutions are far from being pure water, being rich in ions, the properties of solvated ions are of relevance for a wide range of systems, including biological and geochemical environments. We conducted ab initio and classical MD simulations of the alkaline earth metal ions Mg2+ and Ca2+ and of the alkali metal ions Li+, Na+, K+ and Cs+ in pure water and electrolyte solutions containing the counterions Cl– and SO42–. Through a detailed analysis of these simulations, this study reports on the effect of solution chemistry (composition and concentration of the solution) to the ion–water structural properties and interaction strength, and to the dynamics, hydrogen bond network, and low-frequency dynamics of the ionic solvation shell. Except for the ion–water radial distribution function, which is weakly dependent on the counter-ions and concentrations, we found that all other properties can be significantly influenced by the chemical characteristics of the solution. Calculation of the velocity autocorrelation function of magnesium ions, for example, shows that chlorine ions located in the second coordination shell of Mg2+ weaken the Mg(H2O)62+ hydration ‘cage’ of the cation. The result reported in this study suggest that ionic solvation shell can be significantly influenced by the interactions between other ions present in solution ions, especially those of opposite charge. In more general terms, the chemical characteristics of the solution, including the balance between ion-solvent and ion-ion interactions, could result in significant differences in behavior and function of the ionic solvation shell. </div>

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Density functional theory based molecular dynamics study of solution composition effects on the solvation shell of metal ions

Physical Chemistry Chemical Physics ◽

10.1039/d0cp01957g ◽

2020 ◽

Vol 22 (28) ◽

pp. 16301-16313

Author(s):

Xiangwen Wang ◽

Dimitrios Toroz ◽

Seonmyeong Kim ◽

Simon L. Clegg ◽

Gun-Sik Park ◽

...

Keyword(s):

Molecular Dynamics ◽

Metal Ions ◽

Density Functional ◽

Pure Water ◽

Earth Metal ◽

Electrolyte Solutions ◽

Solvation Shell ◽

Functional Theory ◽

Composition Effects ◽

Alkaline Earth Metal Ions

We present an ab initio molecular dynamics study of the alkali metal ions Li+, Na+, K+ and Cs+, and of the alkaline earth metal ions Mg2+ and Ca2+ in both pure water and electrolyte solutions containing the counterions Cl− and SO42−.

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Soil solution chemistry of contrasting soils amended with heavy metals

Soil Research ◽

10.1071/sr98055 ◽

1999 ◽

Vol 37 (5) ◽

pp. 993 ◽

Cited By ~ 20

Author(s):

H. J. Percival ◽

T. W. Speir ◽

A. Parshotam

Keyword(s):

Heavy Metals ◽

Heavy Metal ◽

Metal Ions ◽

Cation Exchange ◽

Soil Solution ◽

Solution Chemistry ◽

Percentage Increase ◽

Soil Solution Chemistry ◽

Soil Solutions ◽

Wide Range

The soil solution chemistry of heavy metal amended soils is of great importance in assessing the bioavailability of heavy metals and their toxicity to the soil biota. Three contrasting soils were amended with Cd(II), Cu(II), Ni(II), Pb(II), Zn(II), and Cr(III) nitrate salts at rates of 10–100 mmol/kg. This concentration range was chosen to encompass a wide range of effects on sensitive soil biochemical properties as part of a larger project. Soil solutions were extracted and analysed for pH, and for concentrations of heavy metals, and major cations and anions. Heavy metal speciation was calculated with the GEOCHEM-PC model. Heavy metal concentrations in the soil solutions increased both in absolute terms and as a percentage of added heavy metal as amendment rates increased. This observation is due to decreasing specific adsorption (caused by decreasing pH induced by the amendments), and to increasing saturation of cation exchange sites. For all 3 soils, the percentage increase commonly follows the order Cr(III) < Pb < Cu < Ni < Cd < Zn. The percentage of each metal held in the soil solution increased from soil to soil as cation exchange capacity, and therefore sorptivity, decreased. Both the concentration and activity of free heavy metal ions were substantially lower than the corresponding total metal concentration. This was ascribed to ion-pairing of metal ions with anions, particularly nitrate introduced in the amending solutions, as well as to increases in ionic strength as a result of amendment. Metal-anion species were mainly inorganic but where Cu and Pb were relatively low in concentration because of strong adsorption by the soils, organic complexation was likely to be significant. Speciation trends were similar for the 3 soils but different in magnitude.

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Preface

Pure and Applied Chemistry ◽

10.1351/pac20108210iv ◽

2010 ◽

Vol 82 (10) ◽

pp. iv

Author(s):

Thomas Hofer

Keyword(s):

Pure Water ◽

Solution Chemistry ◽

Solution Nmr ◽

Simulation Studies ◽

Porous Coordination Polymers ◽

Chemical Research ◽

Poster Sessions ◽

Wide Range ◽

Poster Award ◽

Physical And Chemical

The 31st International Conference on Solution Chemistry (ICSC-31) was held 21-25 August 2009 in Innsbruck, Austria. This conference series covers a wide range of topics related to solution chemistry, such as spectroscopy, thermodynamics, and kinetics to name just a few, addressing experimentalists and theoreticians alike.Seventeen outstanding plenary and invited lectures were given by renowned scientists. The topics of the plenaries were solution NMR stuctures of proteins (J. Wüthrich), porous coordination polymers (S. Kitagawa), ab initio-based water potentials for simulation studies (S. Xantheas), and the hydration structures of metal ions in solution (I. Persson). Additionally, 33 oral contributions were presented and two poster sessions were held. A total of 29 countries were represented in this conference. The best poster award was given to Matjaz Boncina for his poster entitled "Thermodynamics of the ion–lysozyme association". Pierre Turq presented details of the next ICSC meeting to be held in 2011 in La Grande Motte, France.Eight papers based on lectures presented at the ICSC-31 are included in this issue of Pure and Applied Chemistry. The manuscripts cover investigations using different spectroscopic approaches, molecular simulation studies as well as thermodynamic measurements. The systems treated range from pure water and aqueous solution to ionic liquids and solutions containing polyelectrolytes. These contributions feature the major themes of the conference, serve as a representative view of current activities in the field of solution chemistry, and demonstrate that solutions still prove to be challenging targets for contemporary physical and chemical research alike.Thomas HoferBernhard RandolfConference Editors

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Wetting of glass surface using natural surfactants

Micro and Nanosystems ◽

10.2174/1876402912666200219111447 ◽

2020 ◽

Vol 12 ◽

Author(s):

Nihar Ranjan Biswal

Keyword(s):

Contact Angle ◽

Glass Surface ◽

Pure Water ◽

Amyl Alcohol ◽

Synthetic Surfactant ◽

Wide Range ◽

Different Types ◽

Natural Surfactants ◽

Triton X ◽

Solid Liquid

Background: Surfactant adsorption at the interfaces (solid–liquid, liquid–air, or liquid–liquid) is receiving considerable attention from a long time due to its wide range of practical applications. Objective: Specifically wettability of solid surface by liquids is mainly measured by contact angle and has many practical importances where solid–liquid systems are used. Adsorption of surfactants plays an important role in the wetting process. The wetting behaviours of three plant-based natural surfactants (Reetha, Shikakai, and Acacia) on the glass surface are compared with one widely used nonionic synthetic surfactant (Triton X-100) and reported in this study. Methods: The dynamic contact angle study of three different types of plant surfactants (Reetha, Shikakai and Acacia) and one synthetic surfactant (Triton X 100) on the glass surface has been carried out. The effect of two different types of alcohols such as Methanol and amyl alcohol on wettability of shikakai, as it shows little higher value of contact angle on glass surface has been measured. Results: The contact angle measurements show that there is an increase in contact angle from 47° (pure water) to 67.72°, 65.57°, 68.84°, and 68.79° for Reetha, Acacia, Shikakai, and Triton X-100 respectively with the increase in surfactant concentration and remain constant at CMC. The change in contact angle of Shikakai-Amyl alcohol mixtures are slightly different than that of methanol-Shikakai mixture, mostly there is a gradual increase in contact angle with the increasing in alcohol concentration. Conclusion: There is no linear relationship between cos θ and inverse of surface tension. There was a linear increase in surface free energy results with increase in concentration as more surfactant molecules were adsorbing at the interface enhancing an increase in contact angle.

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Recent developments in materials used for the removal of metal ions from acid mine drainage

Applied Water Science ◽

10.1007/s13201-020-01350-9 ◽

2021 ◽

Vol 11 (2) ◽

Author(s):

Tebogo M. Mokgehle ◽

Nikita T. Tavengwa

Keyword(s):

Heavy Metal ◽

Surface Water ◽

Acid Mine Drainage ◽

Metal Ions ◽

Mine Drainage ◽

Acid Mine ◽

Adsorption Capacities ◽

Ion Imprinted ◽

Wide Range ◽

Ion Imprinted Polymers

AbstractAcid mine drainage is the reaction of surface water with sub-surface water located on sulfur bearing rocks, resulting in sulfuric acid. These highly acidic conditions result in leaching of non-biodegradeable heavy metals from rock which then accumulate in flora, posing a significant environmental hazard. Hence, reliable, cost effective remediation techniques are continuously sought after by researchers. A range of materials were examined as adsorbents in the extraction of heavy metal ions from acid mine drainage (AMD). However, these materials generally have moderate to poor adsorption capacities. To address this problem, researchers have recently turned to nano-sized materials to enhance the surface area of the adsorbent when in contact with the heavy metal solution. Lately, there have been developments in studying the surface chemistry of nano-engineered materials during adsorption, which involved alterations in the physical and chemical make-up of nanomaterials. The resultant surface engineered nanomaterials have been proven to show rapid adsorption rates and remarkable adsorption capacities for removal of a wide range of heavy metal contaminants in AMD compared to the unmodified nanomaterials. A brief overview of zeolites as adsorbents and the developent of nanosorbents to modernly applied magnetic sorbents and ion imprinted polymers will be discussed. This work provides researchers with thorough insight into the adsorption mechanism and performance of nanosorbents, and finds common ground between the past, present and future of these versatile materials.

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ChemInform Abstract: THE COMPLEX FORMATION OF BIURET WITH ALKALI AND ALKALINE EARTH METAL IONS. NMR AND SOLUBILITY STUDIES

Chemischer Informationsdienst ◽

10.1002/chin.197925104 ◽

1979 ◽

Vol 10 (25) ◽

Author(s):

K. H. GSTREIN ◽

B. M. RODE

Keyword(s):

Complex Formation ◽

Metal Ions ◽

Alkaline Earth ◽

Earth Metal ◽

Alkaline Earth Metal ◽

Alkaline Earth Metal Ions ◽

Solubility Studies

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Difference of Coordination between Alkali- and Alkaline-Earth-Metal Ions to a Symmetrical α,α′,δ,δ′-Tetramethylcucurbit[6]uril

Inorganic Chemistry ◽

10.1021/ic200109s ◽

2011 ◽

Vol 50 (15) ◽

pp. 6956-6964 ◽

Cited By ~ 39

Author(s):

Wen-Jian Chen ◽

Da-Hai Yu ◽

Xin Xiao ◽

Yun-Qian Zhang ◽

Qian-Jiang Zhu ◽

...

Keyword(s):

Metal Ions ◽

Alkaline Earth ◽

Earth Metal ◽

Alkaline Earth Metal ◽

Alkaline Earth Metal Ions

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Calculation of the primary trajectories of seeds and other particles in strong winds

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1983.0069 ◽

1983 ◽

Vol 219 (1215) ◽

pp. 217-217

Keyword(s):

Equations Of Motion ◽

Aerodynamic Resistance ◽

Reynolds Numbers ◽

Spherical Particles ◽

Spores And Pollen ◽

General Terms ◽

Wide Range ◽

Strong Winds ◽

Dispersal Distances ◽

Enormous Number

The movement of variously dense spherical particles representing a variety of seeds, fruits, spores and pollen, and released from rest into arbitrary winds and a gravitational field is discussed in general terms that account in detail for changes in the quasi-static aerodynamic resistance to motion experienced by such particles during aerial flight. A hybrid analytical-empirical law is established which describes this resistance fairly accurately for particle Reynolds numbers in the range 0—60 000 and that allows for the numerical integration of the equations of motion so as to cover a very wide range of flight conditions. This makes possible the provision of a set of four-parameter universal range tables from which the dispersal distances for an enormous number of practical cases may be estimated. One particular case of particle movement in a region of pseudo-thermal convection is also discussed and this shows how a marked degree of deposition concentration may be induced in some circumstances by such a flow. Botanists and ecologists concerned with seed and particle dispersal in the environment may find the universal range tables of particular interest and use. This is because the tables obviate the need for the integration of the equations of motion when dealing with individual cases and permit an estimation of range purely on the basis of the specified quantities of particle size, density and altitude of release, atmospheric wind speed, density and viscosity, and the acceleration due to gravity.

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