caa a22 4500 378897292 CHVBK 20180305123509.0 cr unu---uuuuu 161128e20041201xx s 000 0 eng 10.1524/ract.92.12.889.55111 doi (NATIONALLICENCE)gruyter-10.1524/ract.92.12.889.55111 Speciation study on complex formation of uranium(VI) with phosphate and fluoride at high temperatures and pressures by time-resolved laser-induced fluorescence spectroscopy [Elektronische Daten] [Akira Kirishima, Takaumi Kimura, Osamu Tochiyama, Zenko Yoshida] The complex formation of U(VI) with phosphate and with fluoride has been studied at elevated temperatures (20-150°C) and pressures (0.1-40MPa) using time-resolved laser-induced fluorescence spectroscopy (TRLFS). Emission spectra and lifetimes of 5×10-5M uranium(VI) in 0.5M NaClO4 solutions in the presence and absence of ligand ions were measured as a function of the pH, ligand concentration, temperature and pressure. The emission intensities and lifetimes of uranium(VI) decreased rapidly with increasing temperature. In contrast, a pressure effect on the fluorescence properties was quite small. The fluorescence decay curves could be resolved into several fluorescent species. The temperature dependence of the lifetimes followed the Arrhenius law, and the activation energies were estimated for the phosphate and fluoride complexes. These results were compared with speciation calculations at several temperatures obtained by using the DQUANT equation and thermodynamic data in the literature. From these comparisons, each component of the fluorescence was identified as a complexed species or a free uranyl ion at several temperatures, indicating that the Arrhenius plot of fluorescence lifetime is an effective method for in-situ speciation of uranyl complexation at elevated temperatures. © 2004 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Kirishima Akira aut Kimura Takaumi aut Tochiyama Osamu aut Yoshida Zenko aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/12/2004(2004-12-01), 889-896 0033-8230 92:12/2004<889 2004 92 ract https://doi.org/10.1524/ract.92.12.889.55111 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.92.12.889.55111 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kirishima Akira aut NATIONALLICENCE 700 1- Kimura Takaumi aut NATIONALLICENCE 700 1- Tochiyama Osamu aut NATIONALLICENCE 700 1- Yoshida Zenko aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/12/2004(2004-12-01), 889-896 0033-8230 92:12/2004<889 2004 92 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter