TY - JOUR

T1 - Structural characterization of Am incorporated into calcite

T2 - A TRLFS and EXAFS study

AU - Stumpf, Thosten

AU - Marques Fernandes, M.

AU - Walther, Clemens

AU - Dardenne, Kathy

AU - Fanghänel, Thomas

N1 - Funding information: We gratefully acknowledge the assistance of Annick Froideval during the EXAFS measurements. Thanks to Dirk Bosbach and Felix Brandt for fruitful discussions and for making the flow-through reactor available. This work was financed by the Helmholtz Gemeinschaft Deutscher Forschungszentren (HGF) by supporting the Helmholtz-Hochschul-Nachwuchsgruppe “Aufklärung geochemischer Reaktionsmechanismen an der Wasser/Mineralphasen Grenzfläche.”

PY - 2006/7/17

Y1 - 2006/7/17

N2 - Calcite homogeneously doped with Am(III) and Cm(III) was synthesized in a mixed-flow reactor. The mechanism of incorporation of these actinides (An) into calcite was investigated by time-resolved laser fluorescence spectroscopy. Two different An(III)/calcite species were found. One has been identified as ions bonded onto the calcite surface. The second An(III) species has lost its complete hydration sphere and is incorporated into the calcite bulk structure. Both Cm(III)/calcite and Am(III)/calcite complexes have been characterized by their fluorescence emission spectra and lifetimes. Structural parameters of the incorporated Am(III) species determined by EXAFS indicate a coordination number of 6.3 ± 0.6 and distances of 2.40 ± 0.01   Å for the first Am{single bond}O shell.

AB - Calcite homogeneously doped with Am(III) and Cm(III) was synthesized in a mixed-flow reactor. The mechanism of incorporation of these actinides (An) into calcite was investigated by time-resolved laser fluorescence spectroscopy. Two different An(III)/calcite species were found. One has been identified as ions bonded onto the calcite surface. The second An(III) species has lost its complete hydration sphere and is incorporated into the calcite bulk structure. Both Cm(III)/calcite and Am(III)/calcite complexes have been characterized by their fluorescence emission spectra and lifetimes. Structural parameters of the incorporated Am(III) species determined by EXAFS indicate a coordination number of 6.3 ± 0.6 and distances of 2.40 ± 0.01   Å for the first Am{single bond}O shell.

KW - Americium

KW - Calcite

KW - Curium

KW - Extended X-ray absorption fine structure (EXAFS)

KW - Solid solutions

KW - Surface complexation

KW - Time-resolved laser fluorescence spectroscopy (TRLFS)

UR - http://www.scopus.com/inward/record.url?scp=33747595200&partnerID=8YFLogxK

U2 - 10.1016/j.jcis.2006.06.010

DO - 10.1016/j.jcis.2006.06.010

M3 - Article

AN - SCOPUS:33747595200

VL - 302

SP - 240

EP - 245

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

IS - 1

ER -