DEVELOPMENT OF NEW TECHNIQUE FOR MECHANISM CLARIFICATION OF INTERACTION BETWEEN URANIUM AND HYDROUS METAL OXIDES AS A ROCK WEATHERING COLLOID UNDER UNDERGROUND WATER CONDITION

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In this research, particle induced Xray emission (FIXE) analysis was tested in quantification of the interaction between colloidal particles of hydrous metal oxides and uranium species without disarranging the experimental conditions. The particles and dissolved species of uranium in ng level and metals of sorption matrix were quantitatively determined by PIXE analysis. This means that PIXE can be applied to clarify the sorption mechanism of uranium on colloidal particle of hydrous metal oxides without introducing experimental disturbance. In addition, PIXE combined with the selective enrichment of uranium by chelation in target preparation and the pattern analysis of PIXE spectra were found effective to determine ultra low concentration of 5ppb in solutions containing large amount of elements interfering with X-ray spectrum analysis for uranium. Moreover, uraniumsorption on hydrous oxide colloids of Al and Fe as a rock weathering product was as selective as that of transition metal ions, and uranium and metal elements in colloidal matrix filtrated from aqueous phase can be simultaneously analyzed by PIXE.In the chemical state analysis by PIXE, we examined the energy dispersive measurement of Xray emitted from heavy metals like Cr, Mn and Fe which were bombarded by 70 MeV ^<12>C^<3+> ions and wavelength dispersive measurement of Xray emitted from light elements like AI and Si which were irradiated by 3 MeV pijolons. PIXE using 70 MeV ^<12>C^<3+> irradiation revealed the change in K_β/K_αratio of Xrays in terms of the structural symmetry of chemical compound of heavy metals having 3d orbital electrons. Therefore, this method was confirmed effective as the chemical state analysis technique for heavy metal elements. Though we aimed at the development of wavelength dispersive PIXE device that has the resolution of 2eV in Xray energy range of 0.504-2.16 keV (5 inch phthalic acid rubidium diffraction crystal), the device performance is still at the adjustment stage.