混合电解质溶液在多孔颗粒内扩散的数学模型

MATHEMATICAL MODEL FOR DIFFUSION OF ELECTROLYTE MIXTURES IN POROUS PARTICLES

建立了混合电解质溶液在多孔颗粒内扩散的数学模型,并由此计算了交互扩散效应的大小;讨论了单一扩散系数的菲克定律描述电解质混合物扩散的适用性;用模型处理了HCl-KCl-H_2O体系的实验数据,得出了有效主扩散系数和有效交互扩散系数.

A mathematical model which describes the diffusion behavior and the cross-effects between ternary electrolyte mixtures in porous particles has been developed. The results of the model show that the component, with noinitial concentration gradient, still could diffuse with large flux resulting from the cross effects. When the simple Fick's law is applied to the diffusion of electrolyte mixtures, the effective diffusivities defined by the law are apparent effective diffusivities represented as weighted averages of the main effective diffusivities. The differences between the apparent and the main effective diffusivities depend on the cross effect diffusivities to a great extent. The cross effects will be remarkable if the ions in an electrolyte molecule have very different mobilities. Experiments were designed to obtain the effective diffusivities for HCl-KCl-H2O system. The model developed in this paper can be used to elucidate the internal diffusion behavior of ternary electrolyte systems.