Incorporation versus adsorption

Substitution of Ca²⁺ by Eu³⁺ and Cm³⁺ in aragonite and gypsum

authored by

Moritz Schmidt, Thorsten Stumpf, Clemens Walther, Horst Geckeis, Thomas Fanghänel

Abstract

The aim of the present work is to understand the interaction behaviour of trivalent f-elements with Ca²⁺-bearing mineral phases on a molecular level. This is achieved by use of time-resolved laser fluorescence spectroscopy (TRLFS) with Eu³⁺ and Cm³⁺ as atomic sensors on a trace concentration level. These ions are of special interest as models for trivalent actinides (e.g., Cm(iii), Am(iii) or Pu(iii)) which strongly contribute to radiotoxicity in high level nuclear waste. Results from TRLFS with these trivalent ions show a significantly different mode of interaction in the two cases: while in aragonite only structural incorporation is observed, on gypsum nothing but inner-sphere surface complexes can be found. This shows how the anions forming the coordination sphere of the foreign ion control the formation of solid solutions as opposed to adsorption complexes.

External Organisation(s)

Karlsruhe Institute of Technology (KIT)
Heidelberg University
European Commission Joint Research Centre (JRC)

Type

Article

Journal

Journal of the Chemical Society. Dalton Transactions

Pages

6645-6650

No. of pages

6

ISSN

1477-9226

Publication date

10.07.2009

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Chemistry(all)

Electronic version(s)

https://doi.org/10.1039/b822656c (Access: Unknown)