Laboratory of Mineral Processing, Institute of Mining Engineering, Wroclaw University of Technology, Wybrzeze Wyspianskiego 27, 50-370 Wroclaw, Poland.
J Phys Chem A. 2012 Jun 28;116(25):6465-72. doi: 10.1021/jp211034y. Epub 2012 Jan 31.
A thermodynamic theory is developed for obtaining the enthalpic and entropic contributions to the surface excess Gibbs energy of electrolyte solutions from the dependence of the surface tension on concentration and temperature. For elaboration, accurate activity coefficients in solution as functions of concentration and temperature are required. The theory is elaborated for (1-1) electrolytes and applied to HClO(4), HNO(3), NaCl, NaBr, and LiCl, of which the first two adsorb positively and the other three negatively. One of the conspicuous outcomes is that in all cases, the surface excess entropies slightly decrease with electrolyte activity but remain close to that of pure water, whereas the enthalpy is different from that. The implication is that the driving force for positive or negative adsorption must have an enthalpic origin. This finding can be useful in developing and evaluating theoretical models for the interpretation of surface tensions of electrolyte solutions.
建立了一个热力学理论，用于从表面张力对浓度和温度的依赖关系中获得电解质溶液表面过剩吉布斯自由能的焓和熵贡献。为了详细阐述，需要准确的溶液中作为浓度和温度函数的活度系数。该理论适用于(1-1)型电解质，并应用于 HClO(4)、HNO(3)、NaCl、NaBr 和 LiCl，其中前两种正吸附，后三种负吸附。一个显著的结果是，在所有情况下，表面过剩熵随电解质活度略有降低，但仍接近纯水的熵，而焓则不同。这意味着正或负吸附的驱动力必须具有焓的起源。这一发现对于开发和评估用于解释电解质溶液表面张力的理论模型是有用的。
