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程程,李成保,姜军,徐仁扣,周立祥.用悬液Wien效应探测阳离子在黄棕壤和黑土胶粒双电层中分布的初步研究[J].环境科学学报,2010,30(5):1043-1051

Preliminary study of cation distribution in the electrical double layers of colloidal yellow-brown and black soil particles by Wien effect measurements

摘要：研究了采用悬液Wien效应测定反号离子在土壤胶粒双电层中分布的方法原理,及不同阳离子在黄棕壤和黑土胶粒双电层中的分布规律.试验条件下,这2种土壤的Na⁺饱和胶粒的表面电导率最大,而使表面电导率最小的阳离子是不同的,黄棕壤为Cu²⁺,黑土则为Cd²⁺.黄棕壤和黑土胶粒的表面电导率随阳离子的变化顺序分别为Na⁺>K⁺>Cd²⁺>Pb²⁺>Ca²⁺>La³⁺>Cu²⁺和Na⁺>K⁺>Pb²⁺>La³⁺>Cu²⁺>Ca²⁺>Cd²⁺.除Na⁺和Cd²⁺外,几乎所有阳离子在黄棕壤胶粒扩散层中的比率(ECS/ECad)明显小于黑土,其中Cd²⁺在黄棕壤和黑土胶粒扩散层中的比率分别为0.174和0.0872.黄棕壤和黑土胶粒的ζ电位随阳离子价型的变化顺序,除了钙饱和黑土外,与土壤胶粒表面电导率随阳离子价型的变化顺序完全一致.

Abstract：This paper describes the principle of determination of counter-ion distribution in the electrical double layers of colloidal soil particles by Wien effect measurements on soil suspensions,and the distribution of various cations in the double layers of colloidal yellow-brown and black soil particles. Under the experimental conditions,the surface electrical conductivities of colloidal soil particles saturated with Na⁺ were the largest for both soils,whereas Cu²⁺ and Cd²⁺ counter ions resulted in minimum surface conductivities in the yellow-brown and black soils,respectively. The whole sequence was Na⁺ > K⁺ > Cd²⁺ > Pb²⁺ > Ca²⁺ > La³⁺ > Cu²⁺ for yellow-brown soil and Na⁺ > K⁺ > Pb²⁺ > La³⁺ > Cu²⁺ > Ca²⁺ > Cd²⁺ for black soil. F_or all cations besides Na⁺ and Cd²⁺ the ratio of cations in the diffuse layers to adsorbed cations,EC_S/EC_ad,was significantly less for the yellow-brown soil particles as compared to that for the black soil particles. The EC_S/EC_ad values of Cd²⁺ for yellow-brown and black soil particles were 0.174 and 0.0872,respectively. The sequences of the ζ potentials of the colloidal particles of the two soils,except that of black soil particles saturated with Ca²⁺,were similar to those of the surface electrical conductivities of the soil particles.

Key words：Diffuse layer electrokinetic potential polarizability surface electrical conductivity