几种土壤胶体电荷零点(ZPC)的初步研究

研究土壤胶体的性质有着重要的意义,在许多土壤胶体的特性中,电化学性质是一个重要方面。大家知道,被分散在电解质溶液中的胶体颗粒,在与电解质溶液接触时,便产生了双电层,根据胶粒和溶液界面间游离电荷分布的机制,可以把土壤胶体区分为两种基本类型:(1)完全极化界面的胶体称为恒表面电荷胶体;(2)可逆界面胶体称为恒表面电位胶体^[10,14]。

A PRELIMINARY STUDY ON THE ZERO POINT OF CHARGE (ZPC) OF SOME SOIL COLLOIDS

The present paper deals with the characteristics of surface charge in zero point of charge (CPC) of certain soil colloids, and the problems of terms of the electrometric titration curves. Five soil colloids(<2u) separated from laterite, red earth, yellow brown earth, loess and black soil were used in the present study. The results obtained are summarized as follows: The magnitude of ZPC values of these samples was followed in the order of laterite (4.00),red earth (3.00), yellow brown earth (2.35),loess (2.25) and black soil (2.15). This sequence conformed to the soil zonality. The ZPC values were gradually reduced from south to north, and this tendency was related to the mineralogical composition and the content of organic matter of soils.