A Direct Speciation of Cm(III) in Natural Aquatic Systems by Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS)

Abstract

A direct speciation of Cm(III) traced in three different Gorleben groundwaters is performed by time resolved laser fluorescence spectroscopy (TRLFS) in very dilute concentrations from 7.8 χ 10~9 mol 1" 1 to 6.3 χ IO" 8 mol Γ 1 , which are below the solubility of Cm(III) at the given aquatic neutral pH. As spectroscopic references, fluorescence spectra are produced for individual hydroxides, carbonates, húmate and fulvate of Cm(III). Parallel to the spectroscopic speciation, a thermodynamic speciation is also made based on complexation constants of the predominant aquatic chemical reactions, i.e. hydrolysis, carbonate complexation and húmate complexation. The speciation results from thermodynamic calculation and spectroscopy are compared with one another.

Uptake of trivalent actinides (curium(III)) by hardened cement paste: a time-resolved laser fluorescence spectroscopy study

“…According to the method developed by Horrocks, Jr., and Sudnick [27] and Barthelemy and Choppin [28] for Eu(III) and later 3+ 9 corresponds to a lifetime of 68 ± 3 µs [7,29,30]. When all water molecules are removed from the first coordination sphere, the lifetime is 1250 ± 80 µs [31].…”

“…Time-resolved laser fluorescence spectroscopy (TRLFS) has been proven to be a versatile tool for Cm(III) speciation studies (e.g., [7][8][9][10][11]) and for sorption studies on various solids [12][13][14][15][16][17]. It is capable of identifying different species as well as determining their hydration status [18], thus allowing outer-sphere and inner-sphere surface complexes and species incorporated in the crystal lattice of the solids to be distinguished from each other.…”

Sorption of curium by silica colloids: Effect of humic acid

“…However the exact nature of the sorbed species is only determined through spectroscopic techniques, such as, time resolved laser induced fluorescence spectroscopy (TRLFS) and extended X-ray absorption fine structure spectroscopy (EXAFS). Cm(III) is an excellent fluorescing element and bulk of the detailed structural information about the sorbed species have come from TRLFS of Cm(III) [19][20][21][22].…”

Cm(III) sorption by silica: effect of alpha hydroxy isobutyric acid

“…The geochemical equilibrium speciation code MINTEQA2 was used to calculate Cm 3+ speciation [32] after incorporating the stability constants of Cm 3+ complexes with OH − [33], HIBA [34] and silicic acid [35,36] [36]. The log K of different complexes considered in the calculations are given in Table 1.…”