Statistical Mechanics of Multilayer Sorption: Extension of the Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) Adsorption Isotherms
Statistical Mechanics of Multilayer Sorption: Extension of the Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) Adsorption Isotherms
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DOI：
10.1021/jp203879d
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发表时间：
2011-08-25
影响因子：
3.7
通讯作者：
Clegg, Simon L.
中科院分区：
文献类型：
--
作者：
Dutcher, Can S.;Ge, Xinlei;Clegg, Simon L.
吸附等温线具有重要的实际应用，包括在溶液化学中，它们已被用于模拟极端浓度的液体混合物中的溶剂和溶质活性，例如纯熔体。传统的Brunauer-Emmett-Teller（BET）和Guggenheim-Anderson-de Boer（GAB）模型对于稀溶液（高水活度）不太成功，因为大多数数据都是可用的。在这项工作中，我们扩展这些模型，包括任意数量的额外的吸附单分子层，并利用统计力学，推导出表达式的吉布斯自由能的解决方案和溶质和溶剂的活动。我们证明了可以通过其他方法获得的结果的一致性，并显示如何一个特定的简单的情况下是等同于拉乌尔定律。测试应用程序的方程水活度数据的水溶液在很宽的浓度范围内表明，除了一个单一的额外吸附层的拟合吸附模型大大提高了其准确性，特别是对于低浓度。
Adsorption isotherms have important practical applications, including in solution chemistry where they have been used to model solvent and solute activities in liquid mixtures at extreme concentrations, such as pure melts. The conventional Brunauer-Emmett-Teller (BET) and Guggenheim-Anderson-de Boer (GAB) models are less successful for dilute solutions (high water activities), for which most data are available. In this work we extend these models to include arbitrary numbers of additional adsorbed monolayers and, using statistical mechanics, derive expressions for the Gibbs energies of solutions and for solute and solvent activities. We demonstrate consistency with results that can be obtained by other methods, and show how a particular simple case is equivalent to Raoult's law. Test applications of the equations to water activity data for aqueous solutions over very wide ranges of concentration show that the addition of a single extra adsorbed layer to the fitted adsorption model greatly increases its accuracy, especially for low concentrations.