Journal of Nuclear Fuel Cycle and Waste Technology

Study on the chemical speciation of uranium(VI) species, UO22+, UO2(OH)+, (UO2)2(OH)22+, (UO2)3(OH)5+, has been performed by using time-resolved laser-induced fluorescence spectroscopy. Speciation sensitivity which depends on the excitation wavelength was investigated. We obtained the speciation sensitivity in the order of 10-9 M concentration of U(VI) compounds at the excitation wavelength of 266 nm. The fluorescence spectrum and lifetime of UO22+ were carefully measured at pH 1 and ion strength of 0.1 M. The spectrum showed the four characteristic peaks located around 488, 509, 533, 559 nm and the fluorescence lifetime of 1.920.17 . The wavelength shifts of fluorescence peaks and the change of lifetimes for uranium hydrolysis compounds were compared with those of UO22+. We report on the characteristic features, the shifts of peaks to the longer wavelength direction and the prolonged lifetimes, in the fluorescence of the U(VI) hydrolysis compounds.

Keywords

Uranium(VI),Fluorescence,Chemical Speciation,Laser Spectroscopy