Hydrodynamic Modeling of NOM Transport in UF: Effects of Charge Density and Ionic Strength on Effective Size and Sieving

2009 ◽  
Vol 43 (14) ◽  
pp. 5449-5454 ◽  
Author(s):  
Yanxiao Yuan ◽  
James E. Kilduff
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Hydrodynamic Modeling ◽  
Effective Size

TEMPO-Mediated Oxidation of Pullulan and Influence of Ionic Strength and Linear Charge Density on the Dimensions of the Obtained Polyelectrolyte Chains

1996 ◽  
Vol 29 (20) ◽  
pp. 6541-6547 ◽  
Author(s):  
A. E. J. de Nooy ◽  
A. C. Besemer ◽  
H. van Bekkum ◽  
J. A. P. P. van Dijk ◽  
J. A. M. Smit
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Linear Charge ◽  
Linear Charge Density ◽  
Mediated Oxidation

Effects of Ionic Strength and Charge Density on the Stability of Chloride Complexes of Trivalent Lanthanides

2008 ◽  
Vol 53 (8) ◽  
pp. 1756-1761 ◽  
Author(s):  
Edelmira Fernández-Ramírez ◽  
Melania Jiménez-Reyes ◽  
Marcos J. Solache-Ríos
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Chloride Complexes ◽  
Trivalent Lanthanides ◽  
The Stability

A Continuum Theory for Simulation of Ionic-Strength-Sensitive Hydrogel for BioMEMS Application

2009 ◽  
Vol 74 ◽  
pp. 21-24
Author(s):  
Fu Kun Lai ◽  
Hua Li
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Electrical Potential ◽  
Continuum Theory ◽  
Ionic Concentration ◽  
Fixed Charge ◽  
Buffer Solution ◽  
Fixed Charge Density ◽  
Flux System ◽  
Smart Hydrogel

A continuum multiphysics theory is presented for simulation of the ionic-strength-sensitive hydrogel and surrounding solution. The theory considers the coupled effects of chemical, electrical and mechanical multi-energy domains on the swelling behavior of the ionic-strength-sensitive hydrogel and is thus termed the multi-effect-coupling ionic-strength-stimuli (MECis) model. The MECis model consists of several governing equations, including Nernst-Planck flux system, Poisson equation, fixed charge density and mechanical equilibrium equation, in which the effect of the ionic strength is incorporated into the governing equation of diffusive flux and fixed charge. The theory is capable of simulating the swelling/shrinking behavior of smart hydrogel in buffer solution subject to the change in the ionic strength, and providing the distribution of the ionic concentration and electrical potential for applications of BioMEMS design. Apart from the ionic strength as the main stimulus, the influence of several parameters is discussed in detail, including the initial fixed charge density and Young’s modulus of the hydrogel.

scholarly journals Intermolecular Interactions in Polyelectrolyte and Surfactant Complexes in Solution

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 51 ◽  
Author(s):  
Nasreen Khan ◽  
Blair Brettmann
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Unique Solution ◽  
Electrostatic Interaction ◽  
Molecular Interaction ◽  
Electrostatic Interactions ◽  
Molecular Level ◽  
Polymeric Materials ◽  
Bulk Solution ◽  
Important Class

Polyelectrolytes are an important class of polymeric materials and are increasingly used in complex industrial formulations. A core use of these materials is in mixtures with surfactants, where a combination of hydrophobic and electrostatic interactions drives unique solution behavior and structure formation. In this review, we apply a molecular level perspective to the broad literature on polyelectrolyte-surfactant complexes, discussing explicitly the hydrophobic and electrostatic interaction contributions to polyelectrolyte surfactant complexes (PESCs), as well as the interplay between the two molecular interaction types. These interactions are sensitive to a variety of solution conditions, such as pH, ionic strength, mixing procedure, charge density, etc. and these parameters can readily be used to control the concentration at which structures form as well as the type of structure in the bulk solution.

scholarly journals Separation and Characterization of Highly Charged Polyelectrolytes Using Free-Solution Capillary Electrophoresis

Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1331
Author(s):  
Isabelle Desvignes ◽  
Joseph Chamieh ◽  
Hervé Cottet
Keyword(s):  
Capillary Electrophoresis ◽  
Ionic Strength ◽  
Charge Density ◽  
Electrophoretic Mobility ◽  
Separation Mechanism ◽  
Free Solution ◽  
Counterion Condensation ◽  
Charge Densities ◽  
Effective Mobility

The characterization of statistical copolymers of various charge densities remains an important and challenging analytical issue. Indeed, the polyelectrolyte (PE) effective electrophoretic mobility tends to level off above a certain charge density, due to the occurrence of Manning counterion condensation. Surprisingly, we demonstrate in this work that it is possible to get highly resolutive separations of charged PE using free-solution capillary electrophoresis, even above the critical value predicted by the Manning counterion condensation theory. Full separation of nine statistical poly(acrylamide-co-2-acrylamido-2-methylpropanesulfonate) polymers of different charge densities varying between 3% and 100% was obtained by adjusting the ionic strength of the background electrolyte (BGE) in counter electroosmotic mode. Distributions of the chemical charge density could be obtained for the nine PE samples, showing a strong asymmetry of the distribution for the highest-charged PE. This asymmetry can be explained by the different reactivity ratios during the copolymerization. To shed more light on the separation mechanism, effective and apparent selectivities were determined by a systematic study and modeling of the electrophoretic mobility dependence according to the ionic strength. It is demonstrated that the increase in resolution with increasing BGE ionic strength is not only due to a closer matching of the electroosmotic flow magnitude with the PE electrophoretic effective mobility, but also to an increase of the dependence of the PE effective mobility according to the charge density.

A quantitative analysis of the glomerular charge barrier in the rat

2001 ◽  
Vol 280 (4) ◽  
pp. F646-F656 ◽  
Author(s):  
Jenny Sörensson ◽  
Maria Ohlson ◽  
Börje Haraldsson
Keyword(s):  
Ionic Strength ◽  
Charge Density ◽  
Pore Radius ◽  
Size Selectivity ◽  
Dynamic Changes ◽  
Small Pore ◽  
Fractional Clearance ◽  
Low Ionic Strength ◽  
Neutral Polymer

Modifying the ionic strength (I) is a gentle way to alter charge interactions, but it cannot be done for studies of the glomerular sieving of proteins in vivo. We therefore perfused 18 isolated rat kidneys with albumin solutions of different ionic strengths at a low temperature (cIPK) to inhibit tubular uptake and protease activity. Four anionic proteins were studied, namely albumin (Alb), orosomucoid (Oro), ovalbumin (Ova), and anionic horseradish peroxidase (aHRP), together with the neutral polymer Ficoll. With normal ionic strength of the perfusate (152 mM), the fractional clearance (θ) was 0.0018 ± 0.0003 for Alb, 0.0033 ± 0.0003 for Oro, 0.090 ± 0.008 for Ova, and 0.062 ± 0.002 for aHRP. These θ values were all lower than for Ficoll of similar hydrodynamic size; e.g., θFicoll 36 Å was >20 times higher than θ for albumin. Low ionic strength (34 mM) increased size selectivity as θ for anionic proteins and Ficoll fell, suggesting a reduction in small-pore radius from 44 ± 0.4 to 41 ± 0.5 Å, P < 0.01. In contrast, low I reduced the charge density of the membrane, ω, to one-quarter of the 20–50 meq/l estimated at normal I. These dynamic changes in ω seem to be due to volume alterations of the charged gel, fluid shifts that easily are accounted for by the changes in electroosmotic pressures. The finding that low ionic strength induces inverse effects on size selectivity and charge density strongly suggests that separate structures of the glomerular wall are responsible for the two properties.

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