An Isotherm-Based Thermodynamic Model of Multicomponent Aqueous Solutions, Applicable Over the Entire Concentration Range
An Isotherm-Based Thermodynamic Model of Multicomponent Aqueous Solutions, Applicable Over the Entire Concentration Range
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DOI：
10.1021/jp310860p
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发表时间：
2013-04-18
影响因子：
2.9
通讯作者：
Clegg, Simon L.
中科院分区：
文献类型：
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作者：
Dutcher, Cari S.;Ge, Xinlei;Clegg, Simon L.
在先前的研究中（Dutcher等人，J. Phys. Chem. C 2011，115，16474-16487; 2012，116，1850-1864），我们基于包括每种溶质上任意数量的水合层的吸附等温线的表达式，推导出多组分液体混合物中的吉布斯能、溶剂和溶质活性以及溶质浓度的方程。在这项工作中，在稀溶液中占主导地位的长程静电相互作用被添加到吉布斯能表达式中，从而扩展了该模型可用于从纯液体溶质到无限稀释的溶剂水的浓度范围。本文导出了溶质活度系数参考状态到无限稀释状态的换算公式。确定了一些简化，特别是等效的吸附位点参数r和溶质的化学计量系数，导致模型参数的数量减少。溶质浓度符合修正的Zdanovskiii-Stokes-罗宾逊混合规则，溶质活度系数符合修正的McKay-Perring关系式，当长程效应方程中考虑了Debye-Huckel项，实际应用于纯电解质水溶液和混合物的渗透系数和活度系数，从低浓度到高浓度都有令人满意的精度，以及对极端浓度和纯液体溶质的物理上合理的外推（超出测量范围）。
In previous studies (Dutcher et al. J. Phys. Chem. C 2011, 115, 16474-16487; 2012, 116, 1850-1864), we derived equations for the Gibbs energy, solvent and solute activities, and solute concentrations in multicomponent liquid mixtures, based upon expressions for adsorption isotherms that include arbitrary numbers of hydration layers on each solute. In this work, the long-range electrostatic interactions that dominate in dilute solutions are added to the Gibbs energy expression, thus extending the range of concentrations for which the model can be used from pure liquid solute(s) to infinite dilution in the solvent, water. An equation for the conversion of the reference state for solute activity coefficients to infinite dilution in water has been derived. A number of simplifications are identified, notably the equivalence of the sorption site parameters r and the stoichiometric coefficients of the solutes, resulting in a reduction in the number of model parameters. Solute concentrations in mixtures conform to a modified Zdanovskii-Stokes-Robinson mixing rule, and solute activity coefficients to a modified McKay-Perring relation, when the effects of the long-range (Debye-Huckel) term in the equations are taken into account Practical applications of the equations to osmotic and activity coefficients of pure aqueous electrolyte solutions and mixtures show both satisfactory accuracy from low to high concentrations, together with a thermodynamically reasonable extrapolation (beyond the range of measurements) to extreme concentration and to the pure liquid solute(s).