1-D fractal model for bentonite colloid diffusion without seepage

Abstract

This paper investigates the 1-D diffusion process of bentonite particle, which is affected by the friction related to the fractal structure of colloid pore. The expression of the pore tortuosity containing pore fractal dimension is deduced to determine the friction, and the evolution rule of pore fractal dimension during diffusion with bentonite volume fraction is reached. The rationality of the modified fractal model is validated via 1-D diffusion test and nuclear magnetic resonance (NMR). Then the influences of electrolyte concentration, initial volume fraction of bentonite, and surface charge density on the colloid diffusion process are analyzed. The results show that the diffusion of bentonite decreases with the increase of electrolyte concentration, and increases with the increase of initial volume fraction and surface charge density. The interfacial volume fraction is correlated with the concentration of electrolyte solution, but not with the initial volume fraction and surface charge density.

Keywords:

• Bentonite
• colloid
• 1-D diffusion
• fractal
• tortuosity

Disclosure statement

No potential conflict of interest was reported by the author.

Additional information

Funding

This research is mainly supported by the National Natural Science Foundation of China [grant number 41630633], [grant number 41877211].