Huertas FJ, Sanchez-Rasero F
Estacion Experimental del Zaidin, C.S.I.C. Profesor Albareda, 1, Granada, 18008, Spain
J Colloid Interface Sci. 1997 Jan 15;185(2):343-54. doi: 10.1006/jcis.1996.4572.
Adsorption isotherms for water vapor, basal spacing, and immersion heats and water desorption heats of Li+, Na+, Mg2+, Ca2+, Cu2+, and Fe3+ montmorillonite are measured at various relative humidities (r.h.). The amount of water adsorbed as a function of r.h. is found to increase gradually, whereas basal spacing increases and the adsorption heat decreases in steps. The water desorption heat also decreases in steps. The entropy of adsorbed water appears to be negative with respect to the entropy of liquid water. A theoretical model is proposed to describe the hydration process of Li+, Na+, Mg2+, Ca2+, Cu2+, and Fe3+ montmorillonites. The experimental adsorption heats are found to have a direct relationship with the sum of the hydration energy of the cations plus expansion energy.
在不同相对湿度（r.h.）下测量了Li⁺、Na⁺、Mg²⁺、Ca²⁺、Cu²⁺和Fe³⁺蒙脱石对水蒸气的吸附等温线、层间距、浸入热以及水脱附热。发现作为相对湿度函数的吸附水量逐渐增加，而层间距增加且吸附热呈阶梯式下降。水脱附热也呈阶梯式下降。相对于液态水的熵，吸附水的熵似乎为负。提出了一个理论模型来描述Li⁺、Na⁺、Mg²⁺、Ca²⁺、Cu²⁺和Fe³⁺蒙脱石的水化过程。发现实验吸附热与阳离子水化能加上膨胀能的总和有直接关系。
