不同阴离子对负电荷胶体(蒙脱石)凝聚的影响  

Effects of Different Anions on Negatively Charged Colloidal Aggregation of Montmorillonite

作　　者：傅强[1] 郭霞[1] 田锐[1] 李航[1] 

机构地区：[1]西南大学资源环境学院/土壤多尺度界面过程与调控重庆市重点实验室,重庆400716

出　　处：《西南大学学报（自然科学版）》2016年第4期28-34,共7页Journal of Southwest University(Natural Science Edition)

基　　金：国家自然科学基金项目(41371249);重庆市基础科学与前沿技术研究专项资助(cstc2015jcyjA00036);中央高校基本业务费专项基金项目(XDJK2015C174)

摘　　要：离子特异性效应在固/液界面反应中普遍存在.土壤溶液中包含众多阴离子和阳离子,由于土壤带净负电荷,其中阴离子对土壤颗粒凝聚的影响被认为很微弱甚至在很多情况下被忽略.以蒙脱石胶体悬液为研究对象,基于动态光散射技术测定了几种不同的一价阴离子(H_2PO_4^-,Cl^-和NO_3^-)对蒙脱石胶体凝聚的影响.研究结果表明,H_2PO_4^-,Cl^-和NO_3^-体系下的凝聚速率显著不同,临界聚沉浓度分别为79.29,13.91,17.07mmol/L,活化能表征的离子特异性效应序列由大到小为H_2PO_4^-,NO_3^-,Cl^-,这意味着阴离子特异性效应会显著影响带负电荷胶体的凝聚.上述差异主要是由几种阴离子核外电子云结构的差异带来的极化效应不同引发的.Hofmeister effects, or specific ion effects, are prevalent in the solid/liquid interface reaction. Vari- ous kinds of anions and cations are present in the soil solution, and because the soil carries a net negative charge, the effects of anions are believed to be so weak that they can be neglected, In the present study, the effects of the interracial reactions of three mono-valent anions （H2 PO;- , C1 and NO7 ） on the aggregation of montmorillonite particles were studied, based on the dynamic light scatting technique. The main results of this study were as follows. The montmorillonite aggregation rate in the three anions systems differed significantly. The CCC values obtained for H2PO4 , Cl- and NO~ were 79.29, 13.91, and 17.07 mmol/L, respectively. The activation energies reflecting specific ion effects in natural soil aggregation process ranked as H2PO;- NO~ ~CI- , indicating that the anion-specific effects can significantly affect negatively charged colloidal aggre- gates. The above-mentioned differences can be interpreted by the polarization effects of the three anions resul- ting from their extranuclear cloud structure.

关 键 词：光散射 阴离子 凝聚 离子特异性效应 

分 类 号：S153.3[农业科学—土壤学]