Colloid-driven radionuclide migration in granite: Experimental evidence and safety assessment Relevance
Year: 2025
Type: article
Abstract: Colloids are increasingly recognized as critical vectors for radionuclide transport in fractured crystalline rocks due to their high sorption capacity and mobility. This study systematically investigates the diffusion behavior of europium (Eu), a trivalent lanthanide analogue for actinides, when associated with bentonite colloids in granite. A multi-technique analytical approach combining Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM/EDS), Transmission Electron Microscopy (TEM), and Secondary Ion Mass Spectrometry (SIMS) was employed to characterize Eu sorption on colloids and quantify its depth-resolved migration in granite matrices. SEM/EDS and TEM confirmed the preferential adsorption of Eu onto iron oxide-rich bentonite colloids, while two of the SIMS depth profiling revealed that colloid-associated Eu exhibits significantly higher diffusion coefficients (2.59×10−18 and 3.12×10−18 m2/s) compared to free Eu ions (4.74×10−19 to 5.13×10−19 m2/s). These results demonstrate that colloid-facilitated transport can enhance the penetration of trivalent radionuclides into crystalline host rocks. The integrated methodology presented here provides robust, spatially resolved data essential for improving predictive models of radionuclide migration and for the safety assessment of high-level radioactive waste geological disposal systems.
Authors: Yu-Hung Shih, Shih-Chin Tsai, Kuan-Ying Hsieh, Tsuey-Lin Tsai, Neng-Chuan Tien
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,400
OpenAlex ID: W4414568801