环境化学
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
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
- Preliminary study of cation distribution in the electrical double layers of colloidal yellow-brown and black soil particles by Wien effect measurements
- 基金项目:国家自然科学基金项目(No.40701079)
- 程程
- 1. 南京农业大学资源与环境科学学院, 南京 210095; 2. 土壤和农业可持续发展国家重点实验室 (中国科学院南京土壤研究所), 南京 210008
- 李成保
- 土壤和农业可持续发展国家重点实验室 (中国科学院南京土壤研究所), 南京 210008
- 姜军
- 土壤和农业可持续发展国家重点实验室 (中国科学院南京土壤研究所), 南京 210008
- 徐仁扣
- 土壤和农业可持续发展国家重点实验室 (中国科学院南京土壤研究所), 南京 210008
- 周立祥
- 南京农业大学资源与环境科学学院, 南京 210095
- 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. For all cations besides Na+ and Cd2+ the ratio of cations in the diffuse layers to adsorbed cations,ECS/ECad,was significantly less for the yellow-brown soil particles as compared to that for the black soil particles. The ECS/ECad 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.
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