Modeling Self-diffusion in Multicomponent Aqueous Electrolyte Systems in Wide Concentration Ranges
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- 作者：Andrzej Anderko and Malgorzata M. Lencka
- 刊名：Industrial & Engineering Chemistry Research
- 出版年：1998
- 出版时间：July 1998
- 年：1998
- 卷：37
- 期：7
- 页码：2878 - 2888
- 全文大小：160K
- 年卷期：v.37,no.7(July 1998)
- ISSN：1520-5045
文摘
A comprehensive model has been developed for calculatingself-diffusion coefficients inmulticomponent aqueous electrolyte systems. The model combinescontributions of long-range(Coulombic) and short-range interactions. The long-rangeinteraction contribution, whichmanifests itself in the relaxation effect, is obtained from thedielectric continuum-based mean-spherical approximation (MSA) theory for the unrestricted primitivemodel. The short-rangeinteractions are represented using the hard-sphere model. In thecombined model, aqueousspecies are characterized by effective radii, which depend on the ionicenvironment. Formulticomponent systems, a mixing rule has been developed on the basisof phenomenologicalequations of nonequilibrium thermodynamics. The effects ofcomplexation are taken into accountby combining the diffusivity model with thermodynamic speciationcalculations. The modelaccurately reproduces self-diffusivities of ions and neutral species inaqueous solutions rangingfrom infinitely dilute to concentrated (up to ca. 30 mol/kg ofH2O). Also, the model makes itpossible to predict diffusivities in multicomponent solutions usingdata for single-solute systems.