钠基蒙脱土水合演化机制

为了查明钠基蒙脱土的水合演化过程，以天然钠基蒙脱土为研究对象，开展在相对湿度（ ）为0～0.98区间的水汽等温吸-脱附试验，通过吸附速率曲线、BET曲线界定钠基蒙脱土各水合阶段及相应的水合主控因素；通过测定晶层 值变化规律，从吸附水影响黏土矿物晶层厚度的角度探讨钠基蒙脱土的水合演化特征；基于傅里叶红外光谱，从水分子结构伸缩振动信息角度对钠基蒙脱土水合演化过程进行定性定量验证；通过热重/差热分析，以吸附水相变所需能量与吸附水重量变化的角度解释钠基蒙脱土的吸附水特征与其水合机制的关系。试验结果表明：在较低相对湿度下（0 0.15），以钠基蒙脱土矿物外表面吸附为主，形成表面吸附水；0.15 0.40为钠基蒙脱土层间阳离子水合阶段；0.40 0.98，为晶层内外表面水合阶段，水分子逐步完整的包裹蒙脱土，形成多层吸附层。钠基蒙脱土的水合演化过程受控于层间钠离子与晶层基面，层间钠离子的水合能影响了钠基蒙脱土水合演化的起始顺序。

Hydration evolution mechanism of sodium montmorillonite

To investigate the hydration evolution process of sodium montmorillonite, the water vapor isothermal adsorption-desorption experiment was conducted for samples with relative humidity ( ) ranging from 0 to 0.98. The water adsorption rate curves and BET curves were proposed to define the hydration evolution process of sodium montmorillonite and the corresponding control factors. By measuring the variation of value, the influence of adsorption water on the thickness of clay mineral layer was studied for sodium montmorillonite hydration characteristics. Based on the theory of Fourier transform infrared spectroscopy, the rationality of the proposed method is also quantitatively validated with water molecular structure vibration information. The relationship between adsorption water characteristics of sodium montmorillonite and its hydration mechanism is explained in terms of the energy required by the phase transition of adsorption water and the mass loss of the adsorption water by thermal analysis. The test results indicate that sodium montmorillonite adsorbsion is mainly on the external surface to form surface adsorption water at 0 0.15, the stage of 0.15 0.40 is the cationic hydration stage between sodium montmorillonite layers, and the stage of 0.40 0.98 is the hydration stage on the inner and outer surface of the crystal layer. The water molecules gradually cover the montmorillonite completely, forming a multi-layer adsorption layer. The hydration process of sodium montmorillonite is controlled by interlayer sodium ions and crystal energy, and the hydration of interlayer sodium ions affects the starting sequence of hydration evolution of sodium montmorillonite.