Colloids present high sorption for many solutes and are considered potential contaminant carriers in geological environments. Experimental quantitative data are required for an adequate description of colloid-mediated transport within natural media. In this paper, the line scan function of SEM/EDS was firstly applied to study colloid diffusion by depth profile in crystalline rock and the apparent diffusion coefficient was estimated to be ~ 6E−18 m2/s for 20 nm gold colloids. This technique can be applied to the prediction of colloid-facilitated radionuclide transport through water-saturated fractured porous rock for safety assessment of geological disposal for high-level radioactive waste.
- Apparent diffusion coefficient (D)