Ion Exchange Theory of Coagulation and its Experimental Verification

From the discrete charge potential equations, the equations of the classical thermodynamics of ion exchange have been obtained: the separation factor equation, the equilibrium constant (mass action law) equation using activities and equivalent ionic fractions and Strickland\u27s equation for the determination of ion valencies by the ion exchange method

Concept of Discrete Charges in the Theory of Eledrokinetic Phenomena

A structure of the electric double layer, based on the concept of discrete ion charges fixed on the surface of the solid in the system »ionic crystal - liquid«, is given. Applying elementary principles of (electro) chemical thermodynamics, electrostatics of elementary particles and the principle of electroneutrality of the systems, and considering the fact that water molecules are dipoles, an equation relating electrokinetic tension with counter ion concentration wa:s deduced. Some available experimental results· on electrokinetic phenomena of AgI were interpreted in the light of the present theory and were shown to confirm it quantitatively in the limits of experimental errors. For other existing theories of the electric double layer similar results were not yet shown to confirm them. The theoretically requested linear Schulze-Hardy rule with the same proportionality constant which was shown up to now to be valid in coagulation and counter ion exchange and adsorption was shown to be valid in electrokinetics too. The obtained definition of the discrete (fixed) charges tension given by the formula: i\u27lcp = !lOcp + z i\u27l1cp + (RT/F) ln(aMIX) is different from the tension defined by the Nernst formula: \u27I\u27 = \u27!Jo + (RT/nF) ln(aolaR

Ion Exchange Theory of Coagulation and its Experimental Verification

From the discrete charge potential equations, the equations of the classical thermodynamics of ion exchange have been obtained: the separation factor equation, the equilibrium constant (mass action law) equation using activities and equivalent ionic fractions and Strickland\u27s equation for the determination of ion valencies by the ion exchange method

Comments on Some Critical Remarks on the Paper »Fixed Charge Double Layer Potential Equations - a Derivation« by J. Th. G. Overbeek

Professor Overbeek in his paper »Some Critical Remarks on the Paper »Fixed Charge Double Layer Potential Equations - a Derivation« by M. Mirnik published in Croat. Chem. Acta 42 (1970) 505, claimed that the criticized paper contains arbitrary assumptions and internal inconsistencies. By careful reading of the criticized paper objective unbiassed readers would probably come to the conclusion that Professor Overbeek\u27s claims do not hold. However, in order to demonstrate and prove that Professor Overbeek\u27s criticism is unjustified the following comments are given to it

Concept of Discrete Charges in the Theory of Eledrokinetic Phenomena

A structure of the electric double layer, based on the concept of discrete ion charges fixed on the surface of the solid in the system »ionic crystal - liquid«, is given. Applying elementary principles of (electro) chemical thermodynamics, electrostatics of elementary particles and the principle of electroneutrality of the systems, and considering the fact that water molecules are dipoles, an equation relating electrokinetic tension with counter ion concentration wa:s deduced. Some available experimental results· on electrokinetic phenomena of AgI were interpreted in the light of the present theory and were shown to confirm it quantitatively in the limits of experimental errors. For other existing theories of the electric double layer similar results were not yet shown to confirm them. The theoretically requested linear Schulze-Hardy rule with the same proportionality constant which was shown up to now to be valid in coagulation and counter ion exchange and adsorption was shown to be valid in electrokinetics too. The obtained definition of the discrete (fixed) charges tension given by the formula: i\u27lcp = !lOcp + z i\u27l1cp + (RT/F) ln(aMIX) is different from the tension defined by the Nernst formula: \u27I\u27 = \u27!Jo + (RT/nF) ln(aolaR

Fixed Charge Double Layer Potential Equations- a Derivation

The symbols have the following meaning: p~ and μ ~. layer are standard chemical potentials, a are activities in equivalents per litre, 8c:pM is the actual electrostatic potential under which counter ions M, M\u27 of valency z, z\u27 are exposed in the outer layer relative to the potential <Jluquid of the liquid phase, and it depends on z, 8°qi is the standard chemical potential expressed as electrostatic potential, 8qi is the variable potential per ,elementary charge of ions of different valencies independent on z, 8 1qi is the difference of the standard electrostatic potentials in· the outer layer and the liquid, i. e. qi ~uter and q:f;quid . a = = 8 1c:pF/RT is the proportionality constant of the linear Schulze- Hardy rule which defines the separation factor S of ion exchange

Comments on Some Critical Remarks on the Paper »Fixed Charge Double Layer Potential Equations - a Derivation« by J. Th. G. Overbeek

Professor Overbeek in his paper »Some Critical Remarks on the Paper »Fixed Charge Double Layer Potential Equations - a Derivation« by M. Mirnik published in Croat. Chem. Acta 42 (1970) 505, claimed that the criticized paper contains arbitrary assumptions and internal inconsistencies. By careful reading of the criticized paper objective unbiassed readers would probably come to the conclusion that Professor Overbeek\u27s claims do not hold. However, in order to demonstrate and prove that Professor Overbeek\u27s criticism is unjustified the following comments are given to it

Fixed Charge Double Layer Potential Equations- a Derivation

The symbols have the following meaning: p~ and μ ~. layer are standard chemical potentials, a are activities in equivalents per litre, 8c:pM is the actual electrostatic potential under which counter ions M, M\u27 of valency z, z\u27 are exposed in the outer layer relative to the potential <Jluquid of the liquid phase, and it depends on z, 8°qi is the standard chemical potential expressed as electrostatic potential, 8qi is the variable potential per ,elementary charge of ions of different valencies independent on z, 8 1qi is the difference of the standard electrostatic potentials in· the outer layer and the liquid, i. e. qi ~uter and q:f;quid . a = = 8 1c:pF/RT is the proportionality constant of the linear Schulze- Hardy rule which defines the separation factor S of ion exchange

Ionic Association and Coagulation

The ion exchange theory of coagulation is verified by quoting experimental. results on coagulation values of K+, Ba2+, and Laa+ for negative AgBr sols in ml.xed solvents, according to which the proportionality constant of the Schulze-Hardy rule is a linear function of 1/D (D = dielectric constant), As critical in the Bjerrum\u27s theory of association the minimum distance between two ions is suggested in which they are separated by only one water molecule

Electrokinetic Studies in Dispersed Systems. V. The Zeta Potential of Agl Precipitates in Mixed Solvents

The influence of acetone-water, dioxane-water and methanolwater solvent mixtures upon the electrokinetic potential of Ag! precipitates has .been studied. The same dielectric constant of the medium yields approximately the same zeta-potential only if the activity of the reversible electrode potential determining ions (constituent ions) is sufficiently large to determine a stable zetapotential in aqueous solution of the same composition. In the isoelectric region, in the case of the theoretically balanced positive and negative potential determining ions adsorption, the influence of solvent dipoles is predominant and specific, and the dielectric constant is not a measure of the electrokinetic potential. The mecha nism of the zeta-potential determining processes is manifold and any extrapolation of a single parameter of the system is insufficient to give answers of general importance