Analysis of several methods to determine the activity of water in solutions of strong electrolytes

Correa, H. A.; Vega, Rolando E.

doi:10.1002/cjce.5450670516

Cited by 4 publications

(6 citation statements)

References 19 publications

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“…The effectiveness of Zdanovskii's rule has been evaluated for many electrolytes, with wide success. [46][47][48][49] Given that Zavitsas' model ensures that mixtures will obey Zdanovskii's rule, the success of Zdanovskii's rule to a wide variety of electrolytes may indicate that Zavitsas' model will work for those multicomponent electrolyte systems as well.…”

Section: Zdanovskii's Rule and Zavitsas' Modelmentioning

confidence: 99%

A method to apply Zavitsas' aqueous electrolyte model to multicomponent solutions and its equivalence to Zdanovskii's rule

Reynolds

2021

AIChE Journal

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Zavitsas developed an aqueous electrolyte thermodynamic model and applied it to single electrolyte solutions previously. Here, a method to apply the model to multicomponent solutions is derived by setting the water activity to the mole fraction of free water in the mixture. The method is shown to work effectively for the CsBr-KNO 3 -H 2 O and CsCl-KNO 3 -H 2 O systems at 100.3 C even at concentrations greater than 6 molal. The largest error in the prediction of water activities was just À0.00365 for the CsBr-KNO 3 -H 2 O system and À0.00631 for the CsCl-KNO 3 -H 2 O system.Zavitsas' model naturally obeys Zdanovskii's rule because when two electrolyte solutions with the same fraction of free water are mixed together, water is obviously going to have that same fraction in the mixture. This means that Zavitsas' model will likely work well for the many electrolytes that obey Zdanovskii's rule.

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Section: Zdanovskii's Rule and Zavitsas' Modelmentioning

confidence: 99%

A method to apply Zavitsas' aqueous electrolyte model to multicomponent solutions and its equivalence to Zdanovskii's rule

Reynolds

2021

AIChE Journal

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“…The one that will be used in this paper is a simple solution approach, a simplification of the McKay and Perring equation . The use of the Zdanovskii–Stokes–Robinson (ZSR) equation , or the isoactive/isopiestic rule , is widely spread to determine the osmotic or the mean activity coefficient of electrolytes in ternary or multicomponent aqueous solutions. − …”

Section: Introductionmentioning

confidence: 99%

“…16 The one that will be used in this paper is a simple solution approach, a simplification of the McKay and Perring equation. 16 The use of the Zdanovskii−Stokes−Robinson (ZSR) equation 17,18 or the isoactive/isopiestic rule 19,20 is widely spread to determine the osmotic or the mean activity coefficient of electrolytes in ternary or multicomponent aqueous solutions. 21−25 Therefore, to improve the simulation of the uranium and plutonium partitioning step of the PUREX process, it is required to improve the uranium(IV) extraction model, including the verification of the simple behavior of the mixture of several components with uranium(IV).…”

Section: ■ Introductionmentioning

confidence: 99%

Validity of the Simple Solution Concept for the Aqueous Quaternary System U(IV) Nitrate–U(VI) Nitrate–Nitric Acid–Water

et al. 2020

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This work focuses on the validity of the simple solution concept of the uranium(IV) nitrate and uranium(VI) nitrate aqueous mixtures through different means such as water activity or density measurements using a simple solution approach. Since these two elements are mixed together in the plutonium uranium redox extraction (PUREX) process during the partitioning step, which separates uranium from plutonium, the knowledge of behavior of this mixture will help in the modeling of this process. This will allow a more precise code to be developed and thus better modeling of the different components involved in the PUREX process. Lately, thermodynamic codes are developed taking into account deviation from ideality. These deviations from ideality are estimated thanks to a solution theory. The one that will be used in this paper is the simple solution approach, a simplification of the McKay and Perring equation. The simple behavior of the uranium(IV) and uranium(VI) mixture will be checked using different methods. The precision of each method will then be discussed. This will be made through the acquisition of water activity, density, and molality of different solutions of uranium(IV) nitrate and uranium(VI) nitrate.

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“…However, an important exception is the “iso-activity” rule, discovered independently by Zdanovskii and Stokes and Robinson . It is known in the literature as Zdanovskii’s rule, the Zdanovskii–Stokes–Robinson rule, or the iso-active/isopiestic rule. , The term Zdanovskii ’ s rule has precedence and is used throughout this work.…”

Section: Introductionmentioning

confidence: 99%

“…Although numerous claims have been made regarding the validity of Zdanovskii’s rule, − ,− no systematic study appears ever to have been performed. This work describes such an investigation.…”

Section: Introductionmentioning

confidence: 99%

An Investigation of Zdanovskii’s Rule for Predicting the Water Activity of Multicomponent Aqueous Strong Electrolyte Solutions

Rowland¹,

May

2012

J. Chem. Eng. Data

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The effectiveness of Zdanovskii's rule as a fundamental method of predicting water activities in mixed aqueous strong electrolyte solutions has been investigated. Unfortunately, when literature data available for more than 100 ternary systems (i.e., two electrolytes plus water) were examined, sufficient measurements were rarely available to test Zdanovskii's rule conclusively. This is because few mixed systems have been studied by more than one (independent) investigator and, in these few cases, the differences between reported water activities are generally much larger than typical estimates of experimental uncertainty. Most of the electrolyte systems considered in this work are found statistically to conform with Zdanovskii's rule but often only within a worryingly large tolerance in residuals. However, when data are taken from a single source, deviations from Zdanovskii's rule, significant in comparison to the stated experimental precision, can often be attributed equally well to small, unrecognized, systematic errors. This dilemma can only be resolved by more experimental measurements of sufficient accuracy to achieve better agreement between independent observers. Our findings imply that (a) confidence in deviations from Zdanovskii's rule typically depends on a subjective judgment of data quality and (b) Zdanovskii's rule, albeit often difficult to validate, provides an impressively general method for estimating water activities in mixed aqueous strong electrolyte solutions, with a certainty that, objectively, is as good as or better than current experimental capability.

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Analysis of several methods to determine the activity of water in solutions of strong electrolytes

Cited by 4 publications

References 19 publications

A method to apply Zavitsas' aqueous electrolyte model to multicomponent solutions and its equivalence to Zdanovskii's rule

A method to apply Zavitsas' aqueous electrolyte model to multicomponent solutions and its equivalence to Zdanovskii's rule

Validity of the Simple Solution Concept for the Aqueous Quaternary System U(IV) Nitrate–U(VI) Nitrate–Nitric Acid–Water

An Investigation of Zdanovskii’s Rule for Predicting the Water Activity of Multicomponent Aqueous Strong Electrolyte Solutions

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