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nanoparticulate material as a barrier, we require detailed understanding of its impact on the geochemistry of radionuclides in the environment (e.g. fission products such as Sr and Cs). Here we show, through combining leaching experiments with XAS analyses, that colloidal silica induces several competing effects on the mobility of Sr and Cs. First, cations within the colloidal silica gel compete with Sr and Cs for surface complexation sites. Second, an increased number of surface complexation sites is provided by the silica nanoparticles and finally, the elevated pH within the colloidal silica increases the surface complexation to clay minerals and the silica nanoparticles. XAS analyses show that Sr and Cs complex predominantly with the clay mineral phases in the soil through inner-sphere surface complexes (Sr) and through complexation on the clay basal surfaces at Si vacancy sites (Cs). For binary soil – colloidal silica gel systems, a fraction of the Sr and Cs complexes with the amorphous silica-like surfaces through the formation of outer-sphere surface complexes. Importantly, the net effect of nanoparticulate colloidal silica gel is to increase the retention of Sr and Cs, when compared to untreated soil and waste materials. Our research opens the door to applications of colloidal silica gel to form barriers within risk management strategies at legacy nuclear sites.
- colloidal silica
- environmental risk management
- legacy nuclear waste
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The effects of colloidal silica grout injection on the geochemistry and speciation of Sr and Cs in soils and wastes
- 6 Citations
- 1 Conference contribution book
Lunn, R., Hamilton, A., Pedrotti, M., Bots, P., Wong, C., El Mountassir, G., Renshaw, J., Maddalena, R., Zhao, C., Sun, L., Stolkin, R., Fairweather, M., Tovey, L., Boxall, C., Hriljac, J., Hyatt, N., Kaltsoyannis, N., Lee, W., Read, D. & Scott, T., 19 Jun 2018, 44th Annual Waste Management Conference (WM2018) : Nuclear and Industrial Robotics, Remote Systems and Other Emerging Technology. Tempe, Arizona, p. 6195-6209 15 p. 18272
Research output: Chapter in Book/Report/Conference proceeding › Conference contribution bookOpen AccessFile
- 1 Invited talk