电位滴定在憎液胶体表面电荷密度研究中的应用

首先讨论了进行电位滴定实验的时候,逐次加入的滴定剂中决定电位离子的数量与被分析憎液胶体分散相粒子表面电荷密度之间的定量关系式,比较了文献中几种不同的零电点的测定方法,进而肯定了其中盐滴定法的可行性.然后,文章介绍了滴定过程中,不溶于水的氧化物或含氧氢氧化物胶体分散相与电解质溶液之间的慢速质子迁移现象,介绍了这一过程的机理以及它对从电位滴定得到的表面电荷密度σ_0值的影响,提出防止这一影响,区分慢速质子迁移与表面电离、表面络合反应对表面电荷的贡献,研究表面吸附机理的实验方法.

THE APPLICATION OF POTENTIOMETRIC TITRATION IN THE STUDY OF SURFACE CHARGE DENSITY ON THE LYOPHOBIC COLLOID DISPERSED PHASE

The relationships between surface charge density at the dispersed phase/solution interface and the amount of the determining ions of titrants added in the experiments of potentiometric titration to insoluble oxide or oxyhydroxide have been deduced firstly. The different methods for the determination of the point of zero charge were compared and the salt titration method was introduced with appreciation secondly. Then, the manifestations and mechanism of the slow proton transfer process which occurs between insoluble oxides or oxyhydroxides and electrolyte aqueous suspensions in literature have been summarized. Finally, this paper has proposed a experimental method distinguishing the attribution of the slow proton transfer process from that of surface ionization and surface complex reaction to surface charge in the study of the mechanism of surface adsorption.