Change of counter ion concentration and of resolving power in a chromatofocusing run

1990 ◽  
Vol 519 (1) ◽  
pp. 217-220 ◽  
Author(s):  
L.A.Æ. Sluyterman ◽  
C. Kooistra
Keyword(s):  
Ion Concentration ◽  
Resolving Power ◽  
Counter Ion

Behavior of Polyelectrolyte Gels in Concentrated Solutions of Highly Soluble Salts

MRS Advances ◽  
2020 ◽  
Vol 5 (17) ◽  
pp. 907-915 ◽  
Author(s):  
Jessica L. Sargent ◽  
Xunkai Chen ◽  
Mitchell C. Brezina ◽  
Sebastian Aldwin ◽  
John A. Howarter ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
High Performance Concrete ◽  
Group Versus ◽  
Transition Metal Ions ◽  
Main Group ◽  
Ion Concentration ◽  
Polyelectrolyte Gels ◽  
Counter Ion ◽  
Versus Transition

ABSTRACTIonic hydrogels are an abundant class of materials with applications ranging from drug delivery devices to high performance concrete to baby diapers. A more thorough understanding of interactions between polyelectrolyte networks and ionic solutes is critical as these materials are further tailored for performance applications in highly targeted ionic environments. In this work, we seek to develop structure-property relationships between polyelectrolyte gels and environments containing high concentrations of multivalent ions. Specifically, this work seeks to elucidate the causes behind differences in hydrogel response to divalent ions of main group metals versus transition metals. PANa-co-PAM hydrogels containing low and high fractions of ionic groups are investigated in solutions of DI water, NaCl, CaCl2, and CuSO4 at concentrations ranging from 5 to 100 mM in order to understand 1) the transient or permanent nature of crosslinks produced in these networks by divalent counter-ions, 2) the role of polymer ionic content in these interactions, and 3) how these interactions scale with salt concentration. Gravimetric swelling and mechanical compression testing are employed to characterize water and salt-swollen hydrogels in order to develop guiding principles to control and manipulate material properties through polymer-counter-ion interactions. The work presented here confirms the formation of permanent crosslinks by transition metal ions, offers explanation for the behavioral discrepancy observed between ionic hydrogels and main group versus transition metal ions, and illustrates how such hydrogel properties scale with counter-ion concentration.

scholarly journals The interaction of calcium ions with glycocholate micelles in aqueous solution

1979 ◽  
Vol 181 (1) ◽  
pp. 61-66 ◽  
Author(s):  
B W A Williamson ◽  
I W Percy-Robb
Keyword(s):  
Aqueous Solution ◽  
Dissociation Constant ◽  
Calcium Ions ◽  
Biological Significance ◽  
Ion Concentration ◽  
Reversible Binding ◽  
Counter Ion ◽  
Soluble Complexes

The formation of soluble complexes of Ca2+ ions and glycocholate has been demonstrated. The dissociation constant is 26 nmol/litre and a maximum of 2 Ca2+ ions are bound to each glycocholate micelle. The formation of this complex is shown to be reversible. Binding is increased by the introduction of phosphatidylcholine into the micelle; it is decreased by a decrease in pH and by increased counter-ion concentration. The biological significance of these effects is discussed.

The effects of counter ion nature on the adsorption of nitrate ion at the mercury/solution interface

1977 ◽  
Vol 55 (22) ◽  
pp. 3871-3881 ◽  
Author(s):  
W. Ronald Fawcett ◽  
James B. Sellan
Keyword(s):  
Ionic Strength ◽  
Ion Concentration ◽  
Surface Excess ◽  
Charge Effects ◽  
Nitrate Ion ◽  
Anion Adsorption ◽  
Solution Interface ◽  
Ionic Adsorption ◽  
Counter Ion ◽  
Capacity Data

The adsorption of nitrate ion at mercury has been studied from two systems at constant ionic strength, namely, xM NaNO3 + (0.2 − x) M NaF and x M KNO3 + (0.2 − x) M KF. The surface excess due to adsorbed nitrate ions was determined from differential capacity data using a modified version of the Hurwitz–Parsons analysis which takes into consideration variation in ionic activity coefficients with solution composition. The amount of adsorbed nitrate ion at a given electrode charge density and bulk nitrate ion concentration is shown to depend markedly on both ionic strength and the nature of the counter ion at the outer Helmholtz plane; when the charge in the diffuse layer is positive, an increase in ionic strength results in more anion adsorption and vice versa. A change in the cation from Na+ to K+ also results in increased anion adsorption. The effects observed are discussed in terms of the Stern–Grahame–Levine model for ionic adsorption which is based on an electrostatic description of the charged interface with consideration of discreteness-of-charge effects.

Influence of different types of natural organic matter on titania nanoparticle stability: effects of counter ion concentration and pH

2014 ◽  
Vol 1 (2) ◽  
pp. 181-189 ◽  
Author(s):  
Julián A. Gallego-Urrea ◽  
Jenny Perez Holmberg ◽  
Martin Hassellöv
Keyword(s):  
Organic Matter ◽  
Natural Organic Matter ◽  
Ion Concentration ◽  
Titania Nanoparticles ◽  
Nanoparticle Stability ◽  
Counter Ion ◽  
Different Types ◽  
Titania Nanoparticle ◽  
Effects Of Ph ◽  
The Stability

Effects of pH, three natural macromolecules and three mono- and divalent electrolytes on the stability of titania nanoparticles.

Influence of Counter-Ion Concentration on the Impinging Jet of Surfactant Solutions

2011 ◽  
Author(s):  
Nguyen Anh Tuan ◽  
Hiroshi Mizunuma
Keyword(s):  
Heat Transfer ◽  
Surfactant Solution ◽  
Impinging Jet ◽  
High Heat ◽  
Ion Concentration ◽  
Past Study ◽  
Surfactant Solutions ◽  
Counter Ion ◽  
High Heat Transfer ◽  
Wall Flow

An impinging jet is characterized by high heat transfer and thus is widely used in cooling and heating process in industry. On the other hand, surfactant solutions reduce pipe friction in turbulent flow and at the same time reduce heat transfer. In our past study, it was found that the surfactant solution with higher counter-ion concentration did not reduce the heat transfer in the impinging jet. This phenomenon suggested that the high heat transfer was characterized by high shear rate in impinging jet and not by turbulence. However, it has not yet been determined satisfactorily how the heat transfer is influenced by surfactant solutions in the impinging jet. Especially, the influence of the counter-ion concentration is important, because the counter-ion changes not only the heat transfer but also the rheology of the surfactant solutions. In this study, we visualized the impinging jet of the surfactant solutions, and the influence of the counter-ion was investigated. The results indicated that the wall flow was remarkably influenced by the counter-ion concentration in the impinging jet. In the case of the surfactant solution with equi-molar counter-ion, the induced wall flow was continued only near the stagnation point. By contrast, the solution with higher molar counter-ion induced the radial boundary layer flow on the wall similar to the water flow. This difference in flow would cause the different heat transfer, and the solution with higher molar counter-ion produces normal heat transfer. When comparing the visualized results of the impinging jet with the numerically simulated results, the qualitative agreement was not satisfactory for the surfactant solution with counter-ion of equi-molar concentration. The simulation used a Bingham model as the rheological equation, the constants of which were obtained from a cone and a plate rheometer. It was suggested that the surfactant solution indicated different rheological behavior in these viscometric flow and impinging jet.

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