蒙脱石表面电荷特性研究及模拟

摘要

以钠基蒙脱石为研究目标,利用酸碱电位滴定方法并结合表面络合模型,对蒙脱石表面电荷特性进行了实验研究及理论计算。结果表明,溶液离子强度为0．1,0．01和0．001 mol/L,蒙脱石的表面零净质子电荷点(pHPZNPC)分别为6．26,7．47和8．18,并且pHPZNPC与溶液离子强度的对数呈良好的线性关系；pH 值＜pHPZNPC,蒙脱石的质子化反应发生在结构电荷位和可变电荷位,p H 值＞p H PZNPC ,蒙脱石的去质子化反应则主要发生在可变电荷位。在质子化-去质子化反应中,蒙脱石表面的结构电荷不会被中和。%The surface charge characteristics of Fuxin (Liaoning province)Na- montmorillonite were studied by acid–base potentiometric titrations and surface complexation models.The results indicated that the point of zero net proton charge values (pHPZNPC)were 6.26,7.47 and 8.18 at 0.1,0.01 and 0.001 mol/L NaNO3 ,respec-tively,and a linear relationship between the pHPZNPC and the logarithm of the ionic strength was obtained;the protonation was take place at structural charge sites at pHHPZNPC and deprotonation was take place at variable charge sites at pH>pHPZNPC.The structural charge were not neutralized in protonation-deprotonation reaction.