caa a22 4500 378927434 CHVBK 20180305123621.0 cr unu---uuuuu 161128e20041101xx s 000 0 eng 10.1524/ract.92.9.691.54982 doi (NATIONALLICENCE)gruyter-10.1524/ract.92.9.691.54982 Effect of humic acid on the sorption of Cm(III) onto γ-Al2O3 studied by the time-resolved laser fluorescence spectroscopy [Elektronische Daten] [X. K. Wang, Thomas Rabung, Horst Geckeis, Petra J. Panak, R. Klenze, Thomas Fanghänel] Sorption of Cm(III) onto γ-alumina coated with humic acid (HA) is studied by the Time Resolved Laser Fluorescence Spectroscopy (TRLFS). The experiments are performed at 0.1M NaClO4, 0.44g/L γ-Al2O3, 10mg/L HA and at a metal ion concentration of 2×10-7mol/L. At the investigated pH range (4 to 10) HA is completely sorbed to γ-Al2O3. The excitation spectrum of Cm(III) bound to HA/γ-Al2O3 in the wavelength range 370-400nm exhibits broad flat bands very different from those obtained for the Cm(III) aquo ion and the Cm(III)-γ-Al2O3 surface complex, respectively. The spectrum, lacking distinctive structure due to intramolecular energy transfer processes, points to the predominant binding of the Cm(III) to surface-bound HA. TRLFS experiments performed at two different excitation wavelengths (λex=355 and 396.6nm) allow for a differentiation of humic-bound and non-humic-bound Cm(III). Differences in fluorescence spectra obtained at the different excitation wavelengths are found at pH<6.9. They are due to the presence of the non-complexed Cm(III) aquo ion which is not detected in the indirect excitation mode (λex=355nm). At pH≥7, the fluorescence spectra obtained by indirect and direct excitation become congruent and again point to the existence of only humic-bound Cm(III) species. Comparison of peak maxima and fluorescence lifetimes for Cm(III)-HA and Cm(III)-HA/γ-Al2O3, however, reveal differences. The results clearly indicate a contribution of the γ-Al2O3 surface to the Cm(III) binding and, thus, suggest the formation of ternary complexes such as >Al-O-Cm(III)(HA). © 2004 Oldenbourg Wissenschaftsverlag GmbH Laboratory techniques, experiments nationallicence Analytical chemistry nationallicence Inorganic chemistry nationallicence Wang X. K. aut Rabung Thomas aut Geckeis Horst aut Panak Petra J. aut Klenze R. aut Fanghänel Thomas aut Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/9-11/2004(2004-11-01), 691-695 0033-8230 92:9-11/2004<691 2004 92 ract https://doi.org/10.1524/ract.92.9.691.54982 text/html Onlinezugriff via DOI 1 research article jats NATIONALLICENCE 856 40 https://doi.org/10.1524/ract.92.9.691.54982 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Wang X. K. aut NATIONALLICENCE 700 1- Rabung Thomas aut NATIONALLICENCE 700 1- Geckeis Horst aut NATIONALLICENCE 700 1- Panak Petra J. aut NATIONALLICENCE 700 1- Klenze R. aut NATIONALLICENCE 700 1- Fanghänel Thomas aut NATIONALLICENCE 773 0- Radiochimica Acta/International journal for chemical aspects of nuclear science and technology Oldenbourg Wissenschaftsverlag GmbH 92/9-11/2004(2004-11-01), 691-695 0033-8230 92:9-11/2004<691 2004 92 ract CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-gruyter