Activity coefficients of small ions in ion‐exchange resins

Lakshminarayanaiah, N.

doi:10.1002/pol.1963.100010111

Cited by 12 publications

(16 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The theoretical treatments of Katchalsky and Lifson20 and Katchalsky and Michaeli21 predict such a decrease in the activity coefficient of electrolyte in the resin phase with decreasing concentration, although quantitative agreement has not been found by a number of workers. 5,6,11,12 The values of the activity coefficients in the resin phases decrease in the order Nal > NaCl > NaH2P04 and NaCl > CaCI2 > LaCl3, which are the same orders which are observed in aqueous solutions of the same salts. It is not surprising that the ions which form ion pairs of the Bjerrum type most extensively in aqueous solution should be involved to the greatest degree in ionic interactions in the polyelectrolyte gel.…”

Section: Resultsmentioning

confidence: 59%

Donnan Equilibria in Polystyrenesulfonate Gels

Gustafson¹

1966

J. Phys. Chem.

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 59%

Donnan Equilibria in Polystyrenesulfonate Gels

Gustafson¹

1966

J. Phys. Chem.

View full text Add to dashboard Cite

“…The localized counterions due to association with the fixed charges (low values of ~) will have low activity; that is, the activity coefficient of the small ions in the membrane phase would be low. This has been experimentally established by Hills et al (1961) for the PMA-KOH system, by Lakshminarayanaiah (1963) for the PSA-NaC1 system, by Kamo etal. (1971b) for the treated collodion system, and by a number of investigators for other systems (see Lakshminarayanaiah, 1969h for a brief review).…”

Section: Discussionmentioning

confidence: 62%

Measurement of membrane potential and estimation of effective fixed-charge density in membranes

Lakshminarayanaiah

1975

J. Membrain Biol.

Self Cite

View full text Add to dashboard Cite

Electrical potentials Em arising across cross-linked phenolsulfonate membrane separating NaCl solutions of molality M1 and M2 have been measured at 25 degrees C. These values of Em have been used in the Nernst equation to calculate values for the apparent transport number ti(app) for the counterion or the co-ion in the membrane. Values of ti(app) together with the limiting value for the cation transport number in the aqueous phase have been used in the equation developed by Kobatake and co-workers to evaluate the membrane permselectivity Ps as a function of external electrolyte concentration. With the help of the equation relating Ps to phiX, the effective fixed-charge density in the membrane (where phi is a constant, 0 less than phi less than 1, and X is the membrane stochiometric charge density and can be evaluated by chemical analysis of the membrane phase), values for phiX and phi have been determined. Values of phi were low in dilute solutions and increased with increase in the concentration of the external solution. Similar behavior was noted in the case of another membrane system, cross-linked polymethacrylic acid in contact with KOH solutions. On the other hand, the membrane system, "untreated" collodion in contact with KCl solutions, exhibited a behavior in which the values of phi, low in dilute solutions, increased and then decreased following a gradual increase in the external concentration. This slight divergence in its behavior was attributed to the heterogeneity of the collodion membrane structure. The reliability of this potentiometric method to estimate effective fixed-charge density in membranes has been discussed in relation to a similar but old method due to Teorell, Meyer and Sievers. Also the significance of the values derived for phi has been pointed out.

show abstract

“…Assumption (i) stated above is generally made by every investigator although it is commonly recognized that the most homogeneous membrane shows functionally characteristics that are typical of a heterogeneous membrane (Lakshminarayanaiah & Subrahmanyan, 1968). Assumptions (ii) and (iv) have been found to be quite drastic or rather unrealistic (Hills et aL, 1961 a, b;Lakshminarayanaiah, 1963;Lakshminarayanaiah & Subrahmanyan, 1964); whereas assumption (iii) has been shown to have little effect on the membrane parameters (Mackie &Meares, 1955;Boyd &Bunzl, 1967). Similarly, the contribution of factor (v) to membrane potential at ordinary concentrations is very small (Lakshminarayanaiah & Subrahmanyan, 1964).…”

Section: Discussionmentioning

confidence: 99%

Potentiometric estimation of charges in barnacle muscle fibers under internal perfusion

Lakshminarayanaiah

1974

J. Membrain Biol.

Self Cite

View full text Add to dashboard Cite

Single barnacle muscle fibers from Megabalanus Psittacus (Darwin) were internally perfused with a number of solutions of K-acetate of concentration 6"2 which was increased from 100 to 600 mM maintaining a pH of 7.5. The external solutions at the same pH contained 40 mM MgAc 2 and K-acetate of concentration C1 which was varied from 10 through 60 mM. The tonicity of both internal and external fluids was maintained at 1,000 mosmole with sucrose. The membrane potential E m (the potential was referred to the external solution as ground) arising across the fiber membrane was measured using those internal and external solutions which maintained the ratio (C2/C1) at 10. Similar measurements but now maintaining the ratio (C2/C~) at 2, where C~ was the concentration of Tris-C1 in the internal perfusion fluid and was increased from 100 to 250 mM and C2 was the concentration of total C1 in the external fluid which contained 40 mM MgC12 and different amounts of Tris-C1 (120 to 420 raM), were also made using various isotonic solutions at pH 4.0. The measured values of E m corrected for the liquid junction potentials, on interpolation with the theoretical curves of E m plotted against log (1/C1) derived from the theory of membrane potential developed by Teorell and by Meyer and Sievers, gave values of 0.019 and 0.7 M for the density of fixed charges present on the membrane at pH 7.5 (cation selective) and 4.0 (anion selective), respectively. Also, values of 2.3 at pH 7.5 and 1.0 at pH 4.0 were derived for the mobility ratio of cation to anion.It is well recognized that charges present on the surface of biological membranes influence various aspects of biological behavior. A surface charge model has been used by Gilbert and Ehrenstein (1969) to explain some of the voltage-dependent characteristics of the conductance of the nerve fiber. Other biological phenomena, e.g. muscle contraction, protoplasmic streaming, etc., are likely to be greatly influenced by the nature of the charged membrane surfaces. Consequently, a number of techniques, mostly electrokinetic in nature, have been utilized by a number of investigators (see Gilbert, 1971 for a brief review) to estimate the density of charges present in membranes of various biological preparations. Recently,

show abstract

Activity coefficients of small ions in ion‐exchange resins

Cited by 12 publications

References 11 publications

Donnan Equilibria in Polystyrenesulfonate Gels

Donnan Equilibria in Polystyrenesulfonate Gels

Measurement of membrane potential and estimation of effective fixed-charge density in membranes

Potentiometric estimation of charges in barnacle muscle fibers under internal perfusion

Contact Info

Product

Resources

About