Equilibrium in Ternary Ion Exchange Systems

Dranoff, Joshua S.; Lapidus, Leon

doi:10.1021/ie50572a038

Cited by 42 publications

(27 citation statements)

References 4 publications

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“…In fact, this result confirms the previous work of Dranoff and Lapidus [12] who suggested the possibility to predict ternary equilibrium from binary data alone. Maining et al [13] studied the Ca 2+ /K + /Na + system with the membrane Nafion 120.…”

Section: Introductionsupporting

confidence: 91%

Ion exchange equilibrium between cation exchange membranes and aqueous solutions of K+/Na+, K+/Ca2+, and Na+/Ca2+

Hannachi

Hamrouni

Dhahbi

2008

Ionics

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Equilibrium between synthetic ion exchangers and solutions of cations has been the subject of this investigation. Competitive ion exchange reactions were studied for two cation exchange membranes (CMX and CRP) involving K + , Na + , and Ca 2+ ions. The ionic strength of the equilibrating solutions was maintained constant, but the molar fraction varied; all experiments were conduced with nitrate as nonexchanging anions at 25°C. Adsorption isotherm for the three binaries systems: K + /Na + , K + /Ca 2+ , and Na + /Ca 2+ were studied. The obtained results show that potassium was the most strongly sorbed and the selectivity order for CMX and CRP membranes is K + >Ca 2+ >Na + at 0.1 M, under the experimental conditions. Selectivity coefficients K Na þ K þ , K Ca 2þ 2 Na þ , and K Ca 2þ 2 K þ for the three binaries and for the two membranes were determined at an ionic strength of 0.1 M and at a constant temperature of 25°C. We remark that all the selectivity coefficient values are quite different from the unit. Ternary equilibrium was taken for the Ca 2+ /K + /Na + system. It was found that binary selectivity data could be successfully used to predict the ternary ion exchange equilibrium.

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Section: Introductionsupporting

confidence: 91%

Ion exchange equilibrium between cation exchange membranes and aqueous solutions of K+/Na+, K+/Ca2+, and Na+/Ca2+

Hannachi

Hamrouni

Dhahbi

2008

Ionics

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“…For this purpose the data were converted into equivalent fractions of each ion in any pair present at equilibrium in the solution and resin phases. These fractions, designated X and Y respectively, are defined for the A-B exchange of Equation (1) by Equations Selectivity coefficients were then determined from the binary data only on each chart. Data for all three concentration levels were averaged to produce the values listed in Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…When a ternary system is considered, it is convenient to describe the exchange reactions and equilibria in terms of the various pairs of ions in the system (1). Thus tor the case of the H -Na+-Cut+ system, one may write the following reactions:…”

Section: Theorymentioning

confidence: 99%

“…For this reason this type of approach was used for analysis of the present data. When a ternary system is considered, it is convenient to describe the exchange reactions and equilibria in terms of the various pairs of ions in the system (1). Thus tor the case of the H -Na+-Cut+ system, one may write the following reactions: H,' + Na,' e Hs+ + Nalt+ ( 4 a ) to resin swelling and hydration, they yield the same relationships.…”

Section: Theorymentioning

confidence: 99%

See 1 more Smart Citation

Ion exchange equilibria in a ternary system

Pieroni¹,

Dranoff²

1963

AIChE Journal

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A study has been made of the cation exchange equilibria between Dowex 50W-X8 resin and aqueous solutions of copper nitrate, nitric acid, and sodium nitrate in binary and ternary mixtures. Experiments were carried out a t room temperature with solutions having total cation concentrations of approximately O.lN, 0.05N, and 0.01N. It was found that the equilibria for any two ions were essentially the same in binary and ternary mixtures. Moreover single valued selectivity coefficients were determined which characterize these data quite well for all three concentration levels. This mokes possible the complete description, for engineering purposes, of I more accessible binary exchange reactions, as ternary equilibria in terms of the simpler and previously suggested (7).One of the controlling factors governing the use of ion exchange separations is the equilibrium distribution of ions, between resin and solution phases, which can be achieved in any given system. For this reason ion exchange equilibria have been widely studied in recent years. [See for example Kitchener (2), Kunin ( 3 ) , or Nachod and Schubert ( 4 ) .] With but ii few exceptions however all of the previous work has dealt with exchanges in binary systems, that is those which contain only two exchanging species, or wjth multicomponent systems containing ions in only trace amounts.In view of the frequent occurrence oi' multicomponent ionic systems in practical situations it seems desirable to extend basic equilibrium studies to systems containing more than two ions. The recent work of Dranoff and Lapidus (1) and of Smith ( 5 ) with ternary cation systems represents a start in this direction. Both of these studies demonstrated the feasibility of representing ternary equilibrium data in terms of binary systems, but only with rather limited data. The present investigation was initiated in order to test this approach more thoroughly over a reasonable concentration range. It is hoped that this will serve as a reliable guide to the eventual treatment of more complex multicomponent exchange systems. THEORYThe theory of equilibrium in ion exchange reactions has been widely studied. It has been shown (2, 3 ) that in most cases the equilibria may be described in terms of either Donnan membrane equilibrium theory or standard mass action chemical equilibrium. When rigorously applied to include resin swelling and solution nonideality these two approaches lead to different equilibrium expressions ( 2 ) . Page 42perimental data adequately for engineering purposes. For this reason this type of approach was used for analysis of the present data.When a ternary system is considered, it is convenient to describe the exchange reactions and equilibria in terms of the various pairs of ions in the system (1). Thus tor the case of the H -Na+-Cut+ system, one may write the following reactions:H,' + Na,' e Hs+ + Nalt+ ( 4 a ) to resin swelling and hydration, they yield the same relationships.In particular for a binary reaction of the form ~H R ' C U~" + 2Hs+ + Curtt+ (4b) ( 4~) b...

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“…Based on the Teorell-Meyer-Sievers hypothesis (Dranoff & Lapidus, 1957;Tombalakian, et al,1967), a pseudo-equilibrium state between each metal ion and counter ion Na + is assumed to exist at the film-membrane interface, respectively. An apparent selectivity coefficient,…”

Section: Based On the Boundary Conditionsmentioning

confidence: 99%