000196714 001__ 196714
000196714 005__ 20181203023426.0
000196714 0247_ $$2doi$$a10.1016/j.gca.2013.10.008
000196714 022__ $$a0016-7037
000196714 02470 $$2ISI$$a000329066500032
000196714 037__ $$aARTICLE
000196714 245__ $$aTrace concentration - Huge impact: Nitrate in the calcite/Eu(III) system
000196714 260__ $$aOxford$$bElsevier$$c2014
000196714 269__ $$a2014
000196714 300__ $$a11
000196714 336__ $$aJournal Articles
000196714 520__ $$aThe interactions of trivalent lanthanides and actinides with secondary mineral phases such as calcite is of high importance for the safety assessment of deep geological repositories for high level nuclear waste (HLW). Due to similar ionic radii, calcium-bearing mineral phases are suitable host minerals for Ln(III) and An(III) ions. Especially calcite has been proven to retain these metal ions effectively by both surface complexation and bulk incorporation. Since anionic ligands (e.g., nitrate) are omnipresent in the geological environment and due to their coordinating properties, their influence on retentive processes should not be underestimated. Nitrate is a common contaminant in most HLW forms as a result of using nitric acid in fuel reprocessing. It is also formed by microbial activity under aerobic conditions. In this study, atomic force microscopy investigations revealed a major influence of nitrate upon the surface of calcite crystals. NaNO3 causes serious modifications even in trace amounts (<10(-7) M) and forms a soft surface layer of low crystallinity on top of the calcite crystal. Time-resolved laser fluorescence spectroscopy of Eu(III) showed that, within this layer, Eu(III) ions are incorporated, while losing most of their hydration shell. The results show that solid solution modelling for actinides in calcite must take into account the presence of nitrate in pore and ground waters. (C) 2013 Elsevier Ltd. All rights reserved.
000196714 700__ $$aHofmann, Sascha$$uKarlsruhe Inst Technol, Inst Nucl Waste Disposal, D-76344 Eggenstein Leopoldshafen, Germany
000196714 700__ $$0244843$$aVoitchovsky, Kislon$$g202038$$uEcole Polytech Fed Lausanne, EPFL STI IMX SUNMIL, CH-1015 Lausanne, Switzerland
000196714 700__ $$aSchmidt, Moritz
000196714 700__ $$aStumpf, Thorsten
000196714 773__ $$j125$$q528-538$$tGeochimica Et Cosmochimica Acta
000196714 909C0 $$0252323$$pSUNMIL$$xU12173
000196714 909CO $$ooai:infoscience.tind.io:196714$$pSTI$$particle
000196714 917Z8 $$x196998
000196714 937__ $$aEPFL-ARTICLE-196714
000196714 973__ $$aEPFL$$rREVIEWED$$sPUBLISHED
000196714 980__ $$aARTICLE