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Basic ion transport characteristics of a homogeneous amphoteric ion exchange membrane (Kanegafuchi Chem. Ind. 1.0-PA-29) were studied by measuring the membrane potentials and conductances. Concentration cell systems of NaCl, KCl, CaCl2, and SrCl2 with a concentration range of 10−1–10−3 mol dm−3 were studied and the electroconductive membrane permeabilities were estimated from the electrochemical data. Generally, Cl− is slightly more permeable than cations under the present experimental conditions, except the result that K+ is more permeable at low concentrations. Unlike the usual uniform cation exchange membrane of which transport characteristics to ions strongly depend upon the number of ionic charges, a “1.0-PA-29” amphoteric membrane exhibits different transport properties for the NaCl and KCl systems. In the NaCl system, the membrane was constantly anionic selective, while in the KCl system, biphasic ion selectivities were observed depending upon the external KCl concentration. Fundamental electrochem...

Basic electrochemical properties of an amphoteric ion-exchange membrane (1.0—PA—29), in which almost equal numbers of cationic and anionic sites are distributed homogeneously over the functionalized polymer networks, were studied for a variety of concentration-cell systems. Unlike the usual uniform ion-exchange membrane, potentiometric permselectivities were demonstrated even for ions of the same charge, as shown by the result that distinctive potential responses were observed for a series of alkali metal chloride, sodium salt, and tetra-alkylammonium chloride systems. The sequence of membrane permeabilities to cations and anions calculated from the electrochemical data could well be correlated to the sequence of the hydrated radii of the respective ions. So the potentiometric responses to any electrolyte system can be predicted from the permeability data or hydrated radius values of individual cations and anions. The present results suggest that the homogeneous amphoteric ion-exchange membrane functions effectively as an ion sieve, sifting out the sizes of permeating hydrated cations and anions.

The membrane potential and conductance of the cation-exchange membrane-aqueous quaternary tetraalkylammonium chloride systems have been measured by using NH4+, tetramethyl-(Me4N+), tetraethyl-(Et4N+), tetrapropyl-(Pr4N+), and tetrabutylammonium ions (Bu4N+). The potential change in the concentration cell with these salts was about 58 mV for a tenfold change of concentration. The membrane conductance in the concentration cell increased with the concentration. The membrane permeability, as estimated from the potential and conductance data, was in the order of NH4+>Me4N+>Et4N+>Pr4N+>Bu4N+; it is proportional to the geometric mean of the activities of exterior solutions. The effective pore size of the membrane was deduced from the conductance data and found to be ca. 10 A. The selective permeation coefficient has been determined from the potential data of the two- and multi-ionic systems. The selectivity data obtained with the two-ionic system were in agreement with those obtained with the multi-ionic system....

In order to clarify the mechanism of ion transport across an amphoteric membrane with sulfonate and N -methylpyridinium groups as exchange sites, membrane potential and membrane conductance measurements were carried out with varying valences of cations and anions of the electrolyte solution. It was shown that the membrane studied behaves as a cation exchange membrane in 1-1 valent and 2-2 valent electrolyte solutions. On the other hand, the membrane function was strongly influenced by the valence of the cation; the membrane in the LaCl 3 system in particular was preferentially anion selective. The permeability coefficients were evaluated according to the theory of nonequilibrium thermodynamics, and ion transport was discussed.

A theory for the ion and solvent transports through membrane has been developed on the basis of nonequilibrium thermodynamics. The fluxes were represented as linear functions of the effective driving potentials. The theory is reduced to that of Katchalsky when the concentration ratio of two aqueous solutions is near unity and the solutions are dilute. The effect of solvent flow on the interionic correlations was discussed. It was pointed out that Despic and Hills’ theory of the electroosmotic effect on the membrane conductance is not valid with respect to both theoretical and experimental aspects. The comparison of the present theory with the previous one was also made. The six independent phenomenological coefficients (elements of the conductance matrix) were experimentally determined as a function of concentration with the concentration cell consisting of the amphoteric ion-exchange membrane and aqueous calcium chloride solutions. The membrane properties were discussed in terms of the conductance matrix...

Transport characteristics of Na+–Ca2+ bi-ionic system with a highly selective cation-exchange membrane were investigated on the basis of nonequilibrium thermodynamic theory. As a principal transport parameter, the membrane permeability matrix or membrane conductance matrix can be estimated from the membrane potential, conductance, and ion flux data. Significances of diffusional and electroconductive processes of ion transport across membrane were systematically discussed in terms of these matrix elements. Partial contributions of inter-cationic (Na+–Na+, Na+–Ca2+, and Ca2+–Ca2+) correlations to the membrane transport process of ions were examined by means of comparing the estimated values of corresponding matrix elements. It was suggested that Ca2+ ions, of which membrane concentrations are kept at high level independently of the Na+/Ca2+ concentration ratio of external aqueous solutions, play a critical role in the membrane transport phenomena. Participations of Cl− transport in the cation-exchange proce...

Transport properties of a cation-exchange membrane-aqueous sodium chloride solution system have been studied. The membrane used was a sulfonated styrene–divinyl benzene copolymer, Neosepta C66-5T. The salt concentration was kept at 10−1 mol dm−3 on one side of the membrane and varied from 10−3 to 10−2 mol dm−3 on the other. The six elements of a conductance matrix have been experimentally determined according to the previous theory and the membrane properties were discussed in terms of conductance elements. All the elements of the conductance matrix were positive within the concentration range studied. This would be characteristic of a cation-exchange membrane. The electrical ion conductance was greater than the diffusional ion conductance by a factor of 10 to 100. The ion-solvent coupling coefficient was much less than the interionic one, although the electroosmotic conductance was ten-times greater than the membrane conductance. The reflection coefficient was close to unity. The electroosmotic propertie...

Utilizing a liquid membrane-aqueous inorganic electrolyte system, the membrane permeability to ion α estimated from the conductance and potential data, Pα, and that at zero electric current estimated from the salt flow and potential data, Pα0, were determined. A solution of calcium hexadecyl sulfate dissolved in 1-octanol and calcium chloride were used as the liquid membrane and the inorganic electrolyte, respectively. The results showed that Pca0⁄Pcl0≈Pca⁄Pcl≈10 and Pcl0≈Ps0, where subscript s refers to the salt. The latter result indicates that the diffusion of a salt through the membrane is governed by the co-ion permeation. It was shown that Pα0 is smaller than Pα and that Pα decreases with increase in the concentration of external calcium chloride solution while Pα0 is nearly independent of the concentration. The difference between Pα and Pα0 can be explained in terms of the elements of permeability and conductance matrices estimated from the electrical and salt flow data.

Transport characteristics of NH4Cl, (CH3)4NCl (TMA–Cl), (C2H5)4NCl (TEA–Cl), (n-C3H7)4NCl (TPA–Cl), and (n-C4H9)4NCl (TBA–Cl) across homogeneous type amphoteric ion exchange membrane (1.0-PA-29, Kanegafuchi Chem. Ind.) were studied. Membrane potentials and conductances of the concentration cell systems were measured to calculate the membrane permeabilities which represent a measure of ionic permselectivity. Membrane potential changed considerably with cationic species and the membrane tended to behave more anionic selectively with increasing bulkiness of cations. The cationic permeabilities calculated from electrochemical data were PNH4>PTMA>PTEA>PTPA>PTBA. Membrane permeabilities to chloride ions, PCl, were greater than those to cations in all the systems studied and it was interesting that PCl values and their dependencies on external electrolyte concentration were almost unchanged irrespective of the difference in cationic species. The present experiment was designed in order to examine the effects of ...

In an amphoteric ion exchange membrane-electrolyte system, three independent experiments were carried out, that is, the membrane potential, membrane conductance and concentration of ions within membrane were measured, respectively. The electrolytes adopted in the systems were NaCl, CaCl2, LaCl3. From the analysis of the results, the specific conductance attributed to Donnan salt within membrane was separated. As a result, it was pointed out that the dynamic state of Donnan salt is obviously different from that of salt in aqueous solution. Furthermore, the comparison between the ions constituting Donnan salt and the counterions which interact with the ion-exchange sites suggested us the existance of two different dynamic states on the ions within membrane.

The ESR spectra of spin-labeled sodium dodecyl sulfate were examined by changing the concentration, temperature, and ionic strength. The broadening of ESR lines due to a monomer surfactant could be explained in terms of an electron-spin exchange and a monomer-micelle exchange. The spin-exchange rate increased with increasing temperature and decreased with increasing ionic strength, i.e., the spin-exchange frequency was closely related to the viscosity of the medium. On the basis of an analysis of the line width above the critical micelle concentration, it was found that the aggregation number of the micelle of this compound and the monomer-micelle exchange frequency were dependent on the ionic strength.

In order to clarify the membrane phenomena in an amphoteric membrane, four different experiments were carried out in a simple electrolyte-amphoteric membrane system. The ion transport numbers obtained from the membrane potential and electrodialysis were approximately in agreement with each other. It was indicated that the transport numbers strongly depended on the ionic valence in electrolyte solution. The membrane permeability coefficient representing the dynamic behavior of ion within membrane was evaluated in terms of membrane potential, transport number, and membrane conductance. In addition, the ionic concentrations within membrane equilibrated with outer electrolyte solution were measured to obtain the mobilities within membrane. The membrane phenomena were discussed on basis of the present experimental results.

The biionic membrane potential was measured with the system in which a solution of calcium chloride was separated by a liquid membrane from a solution of another metal chloride. Four kinds of liquid membranes were prepared by dissolving calcium hexadecyl sulfate, stearate, cholate or deoxycholate in aqueous 1-octanol. All of the membranes studied were nearly permselective to cation. The membrane potential was analysed according to the Goldman-type equation based on the irreversible thermodynamics. The slope of a linear portion of the biionic potential vs. logarithmic activity curve showed fairly good agreement with the theoretical slope, i.e., 2.303×2RT⁄(ZCa+ZM)F per a ten-fold increase in activity, where ZCa and ZM were the valencies of calcium ion and another metal ion M existing across a membrane, respectively. The selective permeation coefficients of various metal ions were estimated for each membrane. The surprisingly small differences in the selective permeation coefficient between uni- and bi-valen...

A conductance matrix describing the ion-transport phenomena in the membrane-three ion system has been determined. It was indicated there that six independent experiments were required in order to determine six independent elements of the conductance matrix. The NaCl–CaCl2–amphoteric membrane system was chosen as the three ion system, and three kinds of fluxes, two kinds of transport numbers, and the membrane conductance were measured. Nine elements were experimentally determined on the assumption of Onsager’s reciprocal relation. The results showed that the order of elements in conductance matrix was gCaCa>gClCl>gNaNa>gCaCl>gNaCl>gCaNa. In addition, it was pointed out that the interactions among ions can never be ignored when the ion-transport phenomena across membrane are studied.

The static and kinetic feature of the reaction of sodium cyanide with 1-bromoalkanes in the presence of various phase transfer catalysts was investigated in the oil/water system by using a layered scintillation method and the mechanism of catalytic action was discussed. From the measurement of equilibrium constants for both reactions of hexadecyltrimethylammonium cyanide with 1-bromooctane and of sodium cyanide with hexadecyltrimethylammonium bromide in organic phase, it was pointed out that the latter reaction was responsible for the advance of overall reaction. It was also found that majority of the phase transfer catalysts exist in the oil phase. It was suggested that an uptake reaction of cyanide ion from the aqueous phase at the interface is essential and that the reaction process does not follow a simple model proposed by Starks et al.

Bi-ionic potentials were measured as a function of the mole fraction of a counterion in a membrane where the total concentration of the carrier or site (hexadecyl pyridinium ion) was kept constant. The membranes used were prepared by dissolving two hexadecyl pyridinium salts, each with a different counterion, in nitrobenzene. When chloride ion was the only counterion, all bi-ionic systems showed a potential as expected from an equation derived in a previous paper. The order of selectivity in the system was perchloride > thiocyanate > nitrate > bromide > chloride. It was found that the additivity rule for bi-ionic potentials held when the counterion in the membrane was either the same as that in both external aqueous electrolyte solutions, or a less selective one. However, when two different counterions coexisted in the membrane, the membrane potential showed a strong dependence upon the counterion composition. These phenomena were interpreted in terms of the membrane equation by taking into account the boundary potentials. A detailed discussion of the results will be given in this paper.

Liquid membrane electrodes selective to alkyl sulfate ions were devised for octyl, decyl, and dodecyl sulfate ions, and employed in the study of micellar solutions. A nitrobenzene solution of hexadecyltrimethylammonium—alkyl sulfate complex was used as the liquid membrane. The membrane potential-logarithmic concentration showed a maximum at the critical micelle concentration (CMC), an increase with the Nernstian slope at the lower concentrations and a decrease at the higher concentrations. Below CMC, the presence of excess inorganic salt did not alter the Nernstian slope, i.e., the liquid membrane was more highly permselective to alkyl sulfate ions than to inorganic anions. From a simple thermodynamic consideration of a micellar solution based on the pseudo phase model of the micelle, the change in the activity of alkyl sulfate ions and the dissociation of the micelle were discussed. It has been deduced that the concentration of the singly dispersed surfactant ions above CMC is reduced with concentration,...

The effect of metallic ions on the monolayer of stearic acid was studied by the rheologi-cal method. (1) It was shown that the development of visco-elastic property of the film is closely correlated with the formation of metal soap. Result obtained by the rheological measurement enables us to classify the metal ions into three groups; Li, Ca, Sr and Ba belong to the 1st, showing the formation of the condensed solid film and the rheological behavior of Voigt model; Th, Fe, Al, Co, Cu and Zn, the 2nd, exhibiting the formation of the expanded solid film and the rheological behavior of Maxwell model; Na, K, Rb and NH4, the 3rd, forming no solid film. These results were discussed in relation to the phenomena observed in the studies of the metal ion monolayer interaction, the adsorption of ion on the built-up film and the effect of ion on the wettability of a solid surface. These phenomena could be correlated with the formation of simple soap or complex metal ion-monolayer aggregate, the 1st and 3rd resulting i...

Direct measurement by the radiotracer method has been carried out in order to determine the surface excess of calcium on the stearic acid monolayer. It did not provoke any disturbance in the monolayer, such as “skimming off” or “building up”. At higher pH values the stearic acid monolayer spread on a calcium chloride solution shows a very remarkable inhomogeneity. It has been pointed out that this inhomogeneity must be taken into consideration in determining the composition of the monolayer. The mixed monolayer of stearic acid and calcium stearate satisfies the equation derived by assuming this monolayer to be a mixture not athermal.

The adsorption of the three alkyl sulfates, SDS, STS and SHS, at the solution-air interface has been measured directly by means of the radiotracer method. It has been proved that the surface adsorption increases with increase in the concentration and has a tendency to be saturated at concentrations near cmc for each detergent solution. The results have shown that the adsorption increases with increasing chain length. The Gibbs adsorption equation has been cheked and discussed.

Counterion activity coefficients in solutions of dextran sulfate with and without added salts were determined potentiometrically by using a cation-exchange membrane and a sodium glass electrode. Dextran sulfate was shown to interact with monovalent cations in the order of preference: K+ > Cs+ > Na+ > Li+, whereas no specificity was found for bivalent cations. On the basis of light-scattering measurements, the expansion of the dextran sulfate polyion in solutions of alkali metal salts was found to fall in the same order as the counterion activity coefficients in salt-free solutions. It was also shown that the dextran sulfate polyion assumes a more extended conformation in magnesium chloride solution than in calcium chloride. These results were substantiated by measurements of solution viscosities.

The adsorption of 35S-labeled dodecyl sulfate ion in the presence of excess sodium salts with anions of various valencies was measured directly by the radiotracer method. The anions of the excess salts were chloride, nitrate, carbonate, ferricyanide and ferrocyanide ions, and the concentrations of the excess salts were all 0.1 N. It was found that the adsorption of dodecyl sulfate ion increased remarkably due to the presence of the excess salt and that the surface tension curves and the adsorption isotherms were almost independent of the type of anions. The behavior of dodecyl sulfate ion was discussed by using the result of the present study together with the previous one, in which the effect of cationic valency and the salt concentration was studied. The logarithmic value of CMC was found to be linear against the logarithmic concentration of excess sodiumchloride and against the valency of cation when the concentrations were all 0.1 N. The reduced surface pressure and the reduced concentration referred ...

The rate of adsorption of sodium dodecyl sulfate, sodium tetradecyl sulfate and sodium hexadecyl sulfate at the solution-air interface has been measured by radiotracer method. It has been found that the surface excess of a detergent is proportional to the concentration of the solution and the square root of time of aging at the initial stage of adsorption. The simple diffusion theory has been checked and it has been found that the results of the present experiment can not be explained by the simple diffusion theory. The idea of energy barrier has tentatively been applied and the values of energy barrier have been calculated.

The adsorption of dodecyl sulfate ion in the presence of various inorganic electrolytes whose concentrations are all 10−4 mol./l. and the adsorption of alkyl sulfate ions in the presence of the excess salt were measured by using S-35 labeled alkyl sulfates. In the presence of various electrolytes, both the rate of adsorption and the equilibrium adsorption of dodecyl sulfate ion increase with the cationic valency of added electrolyte, while they are almost independent of the anionic valency. In the presence of the excess salt, both the rate and the equilibrium adsorption of the alkyl sulfate ions increase with the salt concentration. With increasing concentration of salt the rate of adsorption of the dodecyl sulfate ion approaches the rate of the simple diffusion theory, while that of tetradecyl- and hexadecyl sulfate ion exceeds the value predicted by the simple diffusion theory. It was pointed out that the higher rate of adsorption is attributed to the higher surface activity of solute. The idea of surfa...

The direct measurement of the adsorption of 35S labelled dodecyl sulfate ion at the solution surface and the measurement of the surface tension were carried out on the aqueous solutions of sodium dodecyl sulfate containing a given concentration of an excess salt. The salt concentrations studied were 0.01, 0.1, 0.3, 0.5 and 1N for sodium chloride, and 0.1 N for potassium-magnesium, manganous and aluminum chlorides. 1. The adsorption of dodecyl sulfate ion reaches equilibrium within one minute for all the systems under investigation. 2. The presence of excess of salt gives rise to the remarkable increase in the adsorption of dodecyl sulfate ion, but at the concentrations of excessive salts of about 0.1 N or more, the effects of the concentration and nature of the salts on the adsorption of dodecyl sulfate ion are not so appreciable. 3. The adsorption of dodecyl sulfate ion was well expressed by the Gibbs adsorption equation of n=1 for the systems under investigation.

The presence of aggregates of cobalt ion in the alkaline solution of 10−3 mol./l. CoCl2 was shown by the measurement of self-diffusion coefficients. Large expansion and high rigidity of the stearic acid monolayer caused by cobalt ion in the alkaline solution were accounted for by the interaction of stearate ion in the monolayer with the aggregates of cobalt ion in the solution, resulting in the formation of two-dimensional network structure in the film. This idea was confirmed by the effect of aging of the substrate solution and also by the action of complex-forming agents such as ammonium oxalate and sodium citrate on the monolayer-ion interaction.

The ion-exchange resin–electrolyte solution equilibria were studied on the basis of thermodynamics. The experimental results showed that the external salt activity divided by the co-ion concentration in the ion-exchange resins was linear against the co-ion concentration in the resin. The equilibria were consistently explained by a partition coefficient of salt distribution with the additivity law for the counter ions in the ion-exchange resin. A thermodynamic expression for the ion-exchange reaction was also discussed.