Donnan Membrane Research Articles

Some Electrochemical Properties of New Synthetic Ion Exchange Membranes

The physical, chemical, and electrochemical properties of ion exchange membranes Amberplex C‐1 and Amberplex A‐1, recently developed for commercial application by the Rohm and Haas Company, were investigated and interpreted in the light of a discussion of the Donnan membrane equilibrium for polyelectrolyte membranes. A homogeneous, single‐phase model was assumed valid for these membranes. The cation exchange membrane Amberplex C‐1 was found to be preferentially permeable to cations and the degree of permselectivity was found to vary with concentration of surrounding electrolyte. Similarly, anion exchange membrane Amberplex A‐1 was found to be preferentially permeable to anions. The conductivity of both membranes was found to be a function of the concentration and nature of the surrounding solution. The electrochemical properties of the membranes were correlated with their fixed‐ion concentrations and degrees of hydration.Several possible applications of these membranes having commercial interest are suggested and discussed briefly.

Heterogeneous equilibria at the glass electrode-solution interface

Heterogeneous equilibria a t the glass-solution interface were investigated in connection with the p H response of glasses. The preferential leaching of alkali and other cations from the glass surface by acid aqueous solutions, leaving a silica-rich layer to act as a nonmigratable negatively charged ion, caused an uneven distribution of the migratable ions of the system in accordance with the dictates of the Donnan membrane equilibria and the equat ion of p roduc t s . The uneven distribution of Ag(NH 3 ) t , and Br~ ions for various experimental conditions was readily followed potentiometrically for Corning 015, a series of Na 2 0-CaOSi02, and a series of Na 2 0-S i0 2 glasses. The Donnan membrane theory is compatible with the various experimentally observed phenomena such as the swelling of the glass surface, repression of swelling by high concentrations of electrolytes, voltage departures in alkaline and hydrofluoric-acid solutions, voltage departures in the superacid' ' region, and asymmet ry potent ia ls . However, the Donnan membrane considerations do not account for the preferential voltage response of the glass electrode to hydrogen ions with the complete or par t ia l exclusion of other ions.

Determination of Ionic Activities in Soil‐Water Systems by Means of the Donnan Membrane Equilibrium

Soil Science Society of America JournalVolume 15, Issue C p. 115-119 Section II—Soil Chemistry Determination of Ionic Activities in Soil-Water Systems by Means of the Donnan Membrane Equilibrium† Michael Peech, Michael PeechSearch for more papers by this authorA. D. Scott, A. D. Scott Professor of Soils and Research Assistant, respectively; present position and address of the junior author, Research Assistant Professor, Department of Agronomy, Iowa State College, Ames, Iowa.Search for more papers by this author Michael Peech, Michael PeechSearch for more papers by this authorA. D. Scott, A. D. Scott Professor of Soils and Research Assistant, respectively; present position and address of the junior author, Research Assistant Professor, Department of Agronomy, Iowa State College, Ames, Iowa.Search for more papers by this author First published: 01 January 1951 https://doi.org/10.2136/sssaj1951.036159950015000C0023xCitations: 11 ‡ Contribution from the Department of Agronomy, New York Agricultural Experiment Station, Cornell University, Ithaca, N. Y. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume15, IssueC1951Pages 115-119 RelatedInformation

Donnan Membrane Equilibrium and Direct Dyeing of Cellophane, I II

Donnan Membrane Equilibrium and Direct Dyeing of Cellophane, I II

The Donnan Membrane Equilibrium

THE famous theorem of Gibbs concerning the equality of the chemical potential µ of an independent component throughout a system of co-existent phases in equilibrium at constant temperature and pressure is widely known. It is perhaps not so well known that, if external fields of force or electrically charged components (ions or electrons, for example) are present, an extension of the foregoing theorem is required, though Gibbs himself dealt with this matter in the case of a gravitational field. The subject was very well discussed in an important paper by Milne1 in 1925. If the system of phases be under the action of an external field of potential O per unit of mass, then, corresponding to each independent component, an equation of the type µ + O= constant holds throughout the system. This corresponds to Gibbs' result for a gravitational field. A similar state of affairs holds good for a centrifugal field. A very interesting type of this sort was dealt with on Gibbsian lines by Kai O. Pedersen2 in 1934. Let us now suppose that certain components have associated with them electric charges of amount et- per unit mass (where the subscript refers to such a component i). The presence of the charges will give rise to an electrostatic field, and there may be also present an external electrostatic field. Denote the total electrostatic potential by?. Then, instead of the condition µ = constant, throughout the system of phases, we have the condition µ; + = constant, and if a gravitational field of potential O per unit of mass is also present, the condition becomes µ+ O + e,*Y = constant. If we are dealing with the distribution of ions in ordinary laboratory apparatus (say in experiments on membrane equilibria of ions across a semi-permeable membrane) the term O practically cancels out. Not so, however, the electrical term, which may now be written in the form zi, where Zi F? is the electrovalency of the ionic component i (positive for a cation and negative for an anion) and F is the Faraday constant. Both µ; and the term ZiF refer now to a gram molecule of the ion,i. The expression µ; -l- Zi F has been called the 'electrochemical potential' by Guggenheim3, to whom we are indebted for its introduction and practical use in modern physical chemistry. The Donnan Membrane Equilibrium By Dr. S. G. Chaudhury. Pp. viii + 112 + xv. (Howrah: A. P. Bhattacharya, 1945.) 10 rupees.

The Donnan Membrane Equilibrium.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Donnan Membrane Equilibrium.S. G. Chaudhury and Karl SollnerCite this: J. Phys. Chem. 1946, 50, 3, 288Publication Date (Print):March 1, 1946Publication History Published online1 May 2002Published inissue 1 March 1946https://doi.org/10.1021/j150447a022RIGHTS & PERMISSIONSArticle Views69Altmetric-Citations1LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (118 KB) Get e-Alerts

Donnan Membrane Potential

IN a recent communication in NATURE (July 17, 1943, p. 76) I applied the Boltzmann distribution law to the Donnan membrane equilibrium between two compartments, compartment (1) containing colloidal (or non-diffusible) ions plus diffusible ions, compartment (2) containing only diffusible ions. From the equations obtained, it follows that at the same pH. of the solution the ratio of the membrane potential (E'm) for a dibasic acid to the membrane potential (Em) for a monobasic acid should be where y is the concentration of positive, y + z that of negative ions incompartment (1), x the concentration of positive and negative ions in compartment (2), N* = ½ (N1 + N2), N1 is the valency of the cation, N2 is the valency of the anion, and z is small. At the same pH. value of the solution, z in the case of sulphuric acid is not equal to z in the case of hydrochloric acid.

The Donnan Membrane Equilibrium

WHEN applying the distribution law of Boltzmann to the Donnan membrane equilibrium in two compartments, one containing a mixture of colloidal ions (or non-diffusible ions) and electrolytic solutions and the other electrolytic solutions, we have to assume the compartment containing the colloid or non-diffusible ions to consist of a charged material and a double layer, which extends up to the membrane through which the colloidal particles or non-diffusible ions cannot pass. In the case of colloidal solutions, the membrane may also be considered as a plane, separating the double layer and the bulk of the solution through which the colloidal particles cannot pass. The membrane potential, Em, might be put equal to Ψ1-Ψ2, where Ψ1 is the potential of the ion positive or negative in compartment 1, containing the colloid or the non-diffusible ion, and Ψ2 is the potential of the same ion in the other compartment 2.

Acid-base value and assimilability of fruit juices

1. Fruit juices are buffer salt solutions whose utilization is favored by their acidity. 2. The dissolved sugar in fruit juices is the most readily absorbed constituent. 3. The fruit juices whosepH ranges at about 3—lemon, orange, grape and pineapple create a higher gastric content than those whosepH range fluctuates at about 4—tomato, banana. 4. The base-forming constituents of fruit juices are the slowest to be absorbed by virtue of the existant Donnan membrane equilibria.

II.On the use of Donnan's membrane equilibrium theory for the determination of the charge of colloid particles

(1927). II. On the use of Donnan's membrane equilibrium theory for the determination of the charge of colloid particles. The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science: Vol. 3, No. 13, pp. 22-26.

III.A method for determination of the adsorption of ions on colloidal particles by means of Donnan's Membrane Equilibrium Theory

III.<i>A method for determination of the adsorption of ions on colloidal particles by means of Donnan's Membrane Equilibrium Theory</i>

The potential difference occurring in a Donnan equilibrium and the theory of colloidal behaviour

It is contended by Loeb that the Donnan Membrane Equilibrium, involving the presence of an indiffusible ion, is the basis of the colloidal properties of a protein solution. While the possibility of this conclusion is admitted, it is pointed out that one of the chief arguments employed in its favour by Loeb is incorrect. Loeb shows that the P. D. observed experimentally between a protein and a non-protein solution separated by a membrane agrees very exactly with that “calculated” from the difference in hydrogen-ion concentrations also observed experimentally, and concludes that this supports his theory. As a matter of fact, this equality is a necessary and inevitable consequence of the manner in which his observations were made and of general thermodynamical reasoning, and its proof is independent of any theory of the mechanism by which the P. D. is produced.

DONNAN EQUILIBRIUM AND THE PHYSICAL PROPERTIES OF PROTEINS

1. It is shown that a neutral salt depresses the potential difference which exists at the point of equilibrium between a gelatin chloride solution contained in a collodion bag and an outside aqueous solution (without gelatin). The depressing effect of a neutral salt on the P.D. is similar to the depression of the osmotic pressure of the gelatin chloride solution by the same salt. 2. It is shown that this depression of the P.D. by the salt can be calculated with a fair degree of accuracy on the basis of Nernst's logarithmic formula on the assumption that the P.D. which exists at the point of equilibrium is due to the difference of the hydrogen ion concentration on the opposite sides of the membrane. 3. Since this difference of hydrogen ion concentration on both sides of the membrane is due to Donnan's membrane equilibrium this latter equilibrium must be the cause of the P.D. 4. A definite P.D. exists also between a solid block of gelatin chloride and the surrounding aqueous solution at the point of equilibrium and this P.D. is depressed in a similar way as the swelling of the gelatin chloride by the addition of neutral salts. It is shown that the P.D. can be calculated from the difference in the hydrogen ion concentration inside and outside the block of gelatin at equilibrium. 5. The influence of the hydrogen ion concentration on the P.D. of a gelatin chloride solution is similar to that of the hydrogen ion concentration on the osmotic pressure, swelling, and viscosity of gelatin solutions, and the same is true for the influence of the valency of the anion with which the gelatin is in combination. It is shown that in all these cases the P.D. which exists at equilibrium can be calculated with a fair degree of accuracy from the difference of the pH inside and outside the gelatin solution on the basis of Nernst's logarithmic formula by assuming that the difference in the concentration of hydrogen ions on both sides of the membrane determines the P.D. 6. The P.D. which exists at the boundary of a gelatin chloride solution and water at the point of equilibrium can also be calculated with a fair degree of accuracy by Nernst's logarithmic formula from the value pCl outside minus pCl inside. This proves that the equation x(2) = y ( y + z) is the correct expression for the Donnan membrane equilibrium when solutions of protein-acid salts with monovalent anion are separated by a collodion membrane from water. In this equation x is the concentration of the H ion (and the monovalent anion) in the water, y the concentration of the H ion and the monovalent anion of the free acid in the gelatin solution, and z the concentration of the anion in combination with the protein. 7. The similarity between the variation of P.D. and the variation of the osmotic pressure, swelling, and viscosity of gelatin, and the fact that the Donnan equilibrium determines the variation in P.D. raise the question whether or not the variations of the osmotic pressure, swelling, and viscosity are also determined by the Donnan equilibrium.

THE COLLOIDAL BEHAVIOR OF PROTEINS

1. It is well known that neutral salts depress the osmotic pressure, swelling, and viscosity of protein-acid salts. Measurements of the P.D. between gelatin chloride solutions contained in a collodion bag and an outside aqueous solution show that the salt depresses the P.D. in the same proportion as it depresses the osmotic pressure of the gelatin chloride solution. 2. Measurements of the hydrogen ion concentration inside the gelatin chloride solution and in the outside aqueous solution show that the difference in pH of the two solutions allows us to calculate the P.D. quantitatively on the basis of the Nernst formula See PDF for Equation if we assume that the P.D. is due to a difference in the hydrogen ion concentration on the two sides of the membrane. 3. This difference in pH inside minus pH outside solution seems to be the consequence of the Donnan membrane equilibrium, which only supposes that one of the ions in solution cannot diffuse through the membrane. It is immaterial for this equilibrium whether the non-diffusible ion is a crystalloid or a colloid. 4. When acid is added to isoelectric gelatin the osmotic pressure rises at first with increasing hydrogen ion concentration, reaches a maximum at pH 3.5, and then falls again with further fall of the pH. It is shown that the P.D. of the gelatin chloride solution shows the same variation with the pH (except that it reaches its maximum at pH of about 3.9) and that the P.D. can be calculated from the difference of pH inside minus pH outside on the basis of Nernst's formula. 5. It was found in preceding papers that the osmotic pressure of gelatin sulfate solutions is only about one-half of that of gelatin chloride or gelatin phosphate solutions of the same pH and the same concentration of originally isoelectric gelatin; and that the osmotic pressure of gelatin oxalate solutions is almost but not quite the same as that of the gelatin chloride solutions of the same pH and concentration of originally isoelectric gelatin. It was found that the curves for the values for P.D. of these four gelatin salts are parallel to the curves of their osmotic pressure and that the values for pH inside minus pH outside multiplied by 58 give approximately the millivolts of these P.D. In this preliminary note only the influence of the concentration of the hydrogen ions on the P.D. has been taken into consideration. In the fuller paper, which is to follow, the possible influence of the concentration of the anions on this quantity will have to be discussed.