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反应动力学研究表明 ,在近中性稀溶液中铅锌离子与蒙脱石之间界面反应包括表面配合、层间阳离子交换和金属离子水解沉淀。其中金属离子水解沉淀反应仅在 5 0℃溶液中才明显观察到。而层间阳离子释放包含两个过程 ,即表面快速交换反应和层间扩散作用 ,可用一复合动力学方程描述。反应速率和质量平衡分析表明 ,较高的淌度和快速表面交换作用造成的溶液中氢离子浓度局域性“亏损”是造成金属离子水解沉淀的主要原因。蒙脱石对Zn吸附量大于Pb ,并随温度升高而增加 ,这是由于Zn离子有效静电半径和界面水化系数与Na离子相近 ,更易进入层间交换Na离子
Reaction kinetics studies show that the interface reaction between lead and zinc ions and montmorillonite in near neutral dilute solution includes surface coordination, interlayer cation exchange and metal ion hydrolysis precipitation. Among them, the metal ion hydrolysis and precipitation reaction was only observed in 50 ℃ solution. The release of interlayer cation contains two processes, that is, the rapid exchange reaction and interlayer diffusion, which can be described by a complex kinetic equation. Reaction rate and mass balance analysis showed that local “loss” of hydrogen ion concentration in solution caused by higher mobility and rapid surface exchange was the main reason for the precipitation of metal ions. The adsorption capacity of montmorillonite to Zn is larger than that of Pb, and increases with the increase of temperature. This is due to the fact that the effective electrostatic radius of Zn ion and interface hydration coefficient are similar to Na ions,