scholarly journals Electroosmosis and Electric Conduction of Electrolyte Solutions in Charge-Regulating Fibrous Media

2021 ◽  
Vol 5 (1) ◽  
pp. 19
Author(s):  
Wei L. Chen ◽  
Huan J. Keh
Keyword(s):  
Electric Conductivity ◽  
Cell Model ◽  
Equilibrium Constants ◽  
Electrolyte Solutions ◽  
Ionic Concentration ◽  
Electric Conduction ◽  
Fibrous Media ◽  
Charge Regulation ◽  
Electroosmotic Mobility ◽  
Regulation Model

An analytical study of the electroosmosis and electric conduction of electrolyte solutions in a fibrous medium composed of parallel charge-regulating cylinders with arbitrary electric double layer thickness is presented. A linearized charge regulation model was adopted for the association and dissociation reactions occurring at the amphoteric functional groups over the surfaces of the cylinders, and a unit cell model was employed to accommodate interactions among the cylinders. The electrokinetic equations governing the ionic concentration, electric potential, and liquid flow fields were solved at low zeta potential for the cylinders. Explicit formulas for the electroosmotic mobility and effective electric conductivity in the fiber matrix were obtained. The results indicate that the charge regulation characteristics, such as the equilibrium constants of the reactions occurring at the cylinders’ surfaces and the bulk concentration of the charge-determining ions, influence the surface charge density and potential, electroosmotic mobility, and effective electric conductivity substantially.

Thermodynamics of aqueous EDTA systems: Apparent and partial molar heat capacities and volumes of aqueous EDTA4−, HEDTA3−, H2EDTA2−, NaEDTA3−, and KEDTA3− at 25 °C. Relaxation effects in mixed aqueous electrolyte solutions and calculations of temperature dependent equilibrium constants

1988 ◽  
Vol 66 (4) ◽  
pp. 881-896 ◽  
Author(s):  
Jamey K. Hovey ◽  
Loren G. Hepler ◽  
Peter R. Tremaine
Keyword(s):  
Equilibrium Constants ◽  
Interaction Model ◽  
Electrolyte Solutions ◽  
Heat Capacities ◽  
Mixed Electrolytes ◽  
Temperature Dependent ◽  
Apparent Molar Heat Capacities ◽  
Partial Molar Heat Capacities ◽  
Relaxation Effects ◽  
Young's Rule

Calorimetric and densimetric measurements have led to apparent molar heat capacities and volumes for aqueous solutions of the mixed electrolytes [(CH3)4N]4EDTA + (CH3)4NOH, Na4EDTA + NaOH, and K4EDTA + KOH, and single electrolytes Na2H2EDTA and [(CH3)4N]3[HEDTA] at 25 °C. We have analyzed these results in terms of Young's rule and Pitzer's ion interaction model to obtain standard state partial molar heat capacities and volumes of EDTA4−(aq), HEDTA3−(aq), H2EDTA2−(aq), NaEDTA3−(aq), and KEDTA3−(aq) at 25 °C. For these calculations it was also necessary to evaluate the "relaxation" contribution to the measured heat capacities of some solutions. The partial molar heat capacities obtained here have been used with enthalpies from previous investigations for calculations of several equilibrium constants over wide ranges of temperature; volumes can be used for similar calculations of the effects of pressure.

scholarly journals ASSESSMENT OF BIOLOGY ACTIVITY OF THE PEELING SUBSTANCES BY THE PHYSICOCHEMICAL APPROACHES ON THE SPIROSTOMUM AMBIGUUM CELL MODEL

2021 ◽  
pp. 82-86
Author(s):  
USPENSKAYA E. V. ◽  
PLETENEVA T. V. ◽  
PHAM MY HANH ◽  
KAZIMOVA I. V.
Keyword(s):  
Activation Energy ◽  
Cell Death ◽  
Cell Model ◽  
Equilibrium Constants ◽  
Animal Experiments ◽  
Acid Solutions ◽  
Arrhenius Kinetics ◽  
Functional Changes ◽  
Dead State ◽  
Spirostomum Ambiguum

Objective: To evaluate the biological activity of chemical peeling substances based on enzymatic and Arrhenius kinetics using Spirostomum ambiguum as an alternative approach to animal experiments. Methods: The Spirotox method was used to analyze the mechanism of «xenobiotic-cell» interaction, similar to the Michaelis-Menten enzymatic kinetics. The Hill-Langmuir equation was used to determine the degree of cooperativity in the binding of xenobiotics to cellular receptors. Using the Arrhenius kinetics, the observed activation energy obsEa of cell death in the model solutions of glycolic and carbolic acids was determed, which will allow predicting the toxicity parameters of any peeling substances. Results: The relationship Spirostomum ambiguum lifetime tL-lgC concentration of peeling compound solution made it possible to characterize the moment of cellular transition from the intermediate state C•Ln to the dead state DC, characterized by irreversible structural and functional changes in the cell/death. The values were 5.3 mmol•l-1 for glycolic acid solutions and 2.8 mmol•l-1 for carbolic acid solutions. Equilibrium constants Keq of complexation, the rate of infusoria death fm, and the degree of ligand cooperativity n were calculated. The activation energy °bsEa of cell death was determined in Arrhenius coordinates, which were 210±0.39 kJ·mol-1 and 108±0.09 kJ·mol-1 for glycolic and carbolic acids respectively. The correlation between the values ​​of activation energy and DL50 of mammals (rats) was discovered. Conclusion: The obtained kinetic parameters made it possible, without animals and humans testing, to characterize the mechanisms of interaction of peeling substances with the living cell.

scholarly journals Fluctuation-enhanced electric conductivity in electrolyte solutions

2017 ◽  
Vol 114 (41) ◽  
pp. 10829-10833 ◽  
Author(s):  
Jean-Philippe Péraud ◽  
Andrew J. Nonaka ◽  
John B. Bell ◽  
Aleksandar Donev ◽  
Alejandro L. Garcia
Keyword(s):  
Electric Conductivity ◽  
Electrolyte Solutions

Thermodynamics of molecular interactions in aniline + benzene mixtures

1979 ◽  
Vol 57 (17) ◽  
pp. 2211-2216 ◽  
Author(s):  
Ram K. Nigam ◽  
Prem P. Singh ◽  
Krishan C. Singh
Keyword(s):  
Molecular Interactions ◽  
Molecular Species ◽  
Composition Range ◽  
Equilibrium Constants ◽  
Electrolyte Solutions ◽  
General Behaviour ◽  
Heats Of Mixing ◽  
The Enthalpy Of Formation ◽  
The Ideal ◽  
Model Approach

Heats of mixing, HE, of aniline + benzene at 298.15 and 308.15 K have been measured over the entire composition range. The results have been analysed in terms of Barker's and ideal associated model theory of non-electrolyte solutions. It has been observed that the ideal associated model approach which assumes the presence of AB, AB2, A2B2, and B molecular species well describes (within ± 120 J/mol at the worst) the general behaviour of HE with xB (mole fraction of aniline) over the whole composition range for aniline + benzene mixtures. The equilibrium constants for the various association reactions along with the enthalpy of formation of various molecular species have also been calculated.

Thermodynamics of chloroform and methanol mixtures

1979 ◽  
Vol 57 (4) ◽  
pp. 387-393 ◽  
Author(s):  
Prem P. Singh ◽  
Buta R. Sharma ◽  
Kuljit S. Sidhu
Keyword(s):  
Molecular Species ◽  
Equilibrium Constants ◽  
Electrolyte Solutions ◽  
Excess Gibbs Free Energy ◽  
General Behaviour ◽  
Heats Of Mixing ◽  
Energy Of Mixing ◽  
Free Energy Of Mixing ◽  
The Enthalpy Of Formation ◽  
The Ideal

Heats of mixing and vapour pressures of chloroform (A)+ methanol (Bn) as a function of concentration have been determined at 303.15 K. The excess Gibbs free energy of mixing, GE values, have been obtained from the measured vapour pressure data. The heats of mixing values are negative for solutions rich in methanol but they become positive for solutions rich in chloroform. On the other hand, GE values are positive for all the methanol mole fractions and GE > HE. The results have been analysed in terms of Barker and ideal associated model theory of non-electrolyte solutions. The analysis has revealed that only the ideal associated model approach (which here assumes the presence of AmB (m = 1, 2), ABk (k = 2) and Bl (l = 1) molecular species) well describes the general behaviour of HE with xA over the entire chloroform concentration range for this mixture. The equilibrium constants for the various association reactions along with the enthalpy of formation of the various molecular species have also been calculated.

scholarly journals Charge regulation of colloidal particles in aqueous solutions

2020 ◽  
Vol 22 (42) ◽  
pp. 24712-24728 ◽  
Author(s):  
Amin Bakhshandeh ◽  
Derek Frydel ◽  
Yan Levin
Keyword(s):  
Aqueous Solutions ◽  
Colloidal Particles ◽  
Aqueous Electrolyte ◽  
Electrolyte Solutions ◽  
Charge Regulation ◽  
Aqueous Electrolyte Solutions

We study the charge regulation of colloidal particles inside aqueous electrolyte solutions.

The surface chemistry of kaolinite. III. Microelectrophoresis

1972 ◽  
Vol 25 (9) ◽  
pp. 1857 ◽  
Author(s):  
AS Buchanan ◽  
RC Oppenheim
Keyword(s):  
Ph Dependence ◽  
Equilibrium Constants ◽  
Particle Surface ◽  
Electrolyte Solutions ◽  
Ionic Species ◽  
Hydroxyl Groups ◽  
Electrophoretic Study ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Aluminium Species

Aqueous suspensions of kaolinite from Mt. Egerton, Victoria, have been leached at pH 6.0. In agreement with a theoretical prediction derived from a combination of solubility data and equilibrium constants, more silicon species than aluminium species were found in the leaching liquor. The electrophoretic mobility increases (ie. moves to less negative values) as the leaching at pH 6 proceeds. This has been correlated with the surface hydroxyl groups being more effectively under the control of the less electropositive metal, aluminium. In a binary oxide mineral like kaolinite, the electrical double layer at the particle surface is influenced by the pH dependence of the ionic species in the solution as well as by the pH dependence of the nature of the surface. The results of an electrophoretic study of unleached kaolinite in various aqueous electrolyte solutions is also presented.

scholarly journals Electrical Parameters of SnO2 Based Varistor Ceramics with CaO and BaO Additions

2016 ◽  
Vol 17 (1) ◽  
pp. 81-87 ◽  
Author(s):  
A.V. Gaponov ◽  
O.V. Vorobiov ◽  
A.M. Vasyliev
Keyword(s):  
Electric Field ◽  
Electric Conductivity ◽  
Specific Resistance ◽  
Nonlinear Coefficient ◽  
Linear Shrinkage ◽  
Potential Barrier Height ◽  
Electric Conduction ◽  
Electrical Parameters ◽  
Burning Temperature ◽  
Average Size

In the tested SnO2-Co3O4-Nb2O5-Cr2O3-CuO varistor ceramics the adding of CaO or BaO oxides leads to the decrease of the electric conductivity in the low electric field and correlated increase of the potential barrier height at the SnO2 grain boundaries (from 0.7 to 1.0 eV). The coordinated changes of electrical parameters with the increase of the burning temperature from 1520 to 1620 К (the increase of the linear shrinkage, a grain size, an electric conductivity, a nonlinear coefficient , a normalized nonlinear coefficient , a dielectric permittivity and the decrease of the qualifying electric field E1, an activation energy of electric conduction and a grain specific resistance) prove the barrier mechanism of electric conductivity in the SnO2 based ceramics. The highest data  and = 0.02 cm·V-1 has ceramics with CaO addition baked at 1620 K. According to the impulse experimental data in the high electric field the increase of burning temperature causes the increase of SnO2 grain average size and the decrease of their grain specific resistance . The obtained value  = 1.1 Ohm·cm for SnO2-Co3O4-Nb2O5-Cr2O3-CuO ceramics is the lowest among those found in SnO2 based ceramics.  

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