The Study of Adsorption and Diffusion Behavior of Cs and Se on Granite by SIMS

• Main Authors: Ling-ChenKang, 康綾珍
• Other Authors: Ming-Chee Wu
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/us4ahk

碩士 === 國立成功大學 === 地球科學系 === 106 === In order to understand the influences of the natural barriers to the migration of radionuclides, this study has focused on the diffusion and adsorption behaviors of cesium and selenium to a potential host rock material, the Kinmen granite, of Taiwan. In this study, the basic properties of host rock material, the Kinmen granite, were analyzed by solid phase analysis. The adsorption behaviors of radionuclide (Cs, Se (Ⅳ) and Se (Ⅵ）) to the granite specimens were investigated by batch test. Furthermore, the secondary ion mass spectrometry (SIMS) was implemented to study the adsorption behaviors of radionuclide (Cs and Se (Ⅳ)) to the granite block thin-section undertaking the in-diffusion experiments. The apparent diffusion coefficients (Da) computed via in-diffusion curves fitting were then compared with the results of compacted powdered granite block undertaking the through-diffusion experiments. The results of batch test demonstrated that granite has higher affinity toward Se (Ⅳ) adsorption than Se (Ⅵ) adsorption. No significant observations were obtained for the adsorption of Se (Ⅵ) in granite. In addition, the results of competition shown that when Cs and Se (Ⅳ) were present in solution, the adsorption rate of Cs in granite decreased obviously, while that of Se (Ⅳ) increased obviously. The results of in-diffusion experiments show that the diffusion behavior of cesium in biotite and amphibole (ferromagnesian minerals) is more obvious than that in plagioclase and quartz (ferromagnesian Minerals) of the granite bulk. According to the in-diffusion curve cesium mainly adsorbed onto the biotite, and then to the amphiboles; the apparent diffusion coefficients (Da) for cesium (Cs) to the biotite and to the amphiboles were 9.2×10-19 m2/s and 1.3×10-18 m2/s, respectively. In addition, according to the in-diffusion curve of selenium (Se (Ⅳ))in 12-hours, was found that selenium (Se (Ⅳ)) were adsorbed onto magnetite and biotite; the apparent diffusion coefficients (Da) for selenium (Se (Ⅳ)) to the magnetite and biotite were 1.0×10-14 m2/s and 1.4×10-16 m2/s, respectively.