土壤胶体电位滴定与热分析的初步研究

土壤不仅是一个分散体系,而且其高度分散部分还带电荷。因此,它能与土壤溶液中的离子相互结合,形成双电层。大部分土壤的无机胶体是带负电的,所以主要吸附阳离子。当它在盐基不饱和时就呈酸性,形成所谓胶体酸,胶体酸的缓冲性能既取决于交换性酸的本性,也取决于土壤胶体的本性。因此,了解胶体酸的缓冲性能不仅有助于对土坡酸度本性的认识,也可了解土壤胶体的本性。本文仅就我国几种土壤及其无机胶体部分进行电位滴定与热分析,并与粘土矿物比较以探讨各土壤胶体的缓冲性能与粘粒矿物组成的关系。

PRELIMINARY STUDY ON THE POTENTIOMETRIC TITRATION CURVES OF SOIL COLLOIDS

The present article deals with the potentiometric titration curves,differential thermal curves of acid leached soil colloids from black soil,yellow cultivated loesaial soil and red earth,and from clay minerals including bentonite,illite and kaolinite.The magnitude of buffer capacity is affected by the structural types of clay minerals in the order of montmorillonite>illite>kaolinite.The buffer capacity of different soil colloids varies with the types of soil in the prder of black soil>clayey light colored meadow soil>yellow cultivated loessial soil>red earth,the sequence seems to be related to the composition of clay minerals.