This title appears in the Scientific Report :
2020
Please use the identifier:
http://hdl.handle.net/2128/25949 in citations.
Please use the identifier: http://dx.doi.org/10.1016/j.apgeochem.2020.104713 in citations.
Comparative study of radium and strontium behaviour in contact with cementitious materials
Comparative study of radium and strontium behaviour in contact with cementitious materials
A comparative study of the sorption behaviour of radium and strontium was performed on various cementitiousmaterials including crushed hardened cement pastes (HCP) and concretes as well as a synthesised calcium silicatehydrate (CSH) phase.Rd values obtained for the Ra and Sr uptake on commercial cem...
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Personal Name(s): | Kittnerová, Jana (Corresponding author) |
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Drtinová, Barbora / Štamberg, Karel / Vopálka, Dušan / Evans, Nicholas / Deissmann, Guido / Lange, Steve | |
Contributing Institute: |
Nukleare Entsorgung; IEK-6 |
Published in: | Applied geochemistry, 122 (2020) S. 104713 |
Imprint: |
Amsterdam [u.a.]
Elsevier Science
2020
|
DOI: |
10.1016/j.apgeochem.2020.104713 |
Document Type: |
Journal Article |
Research Program: |
Nuclear Waste Management |
Link: |
OpenAccess OpenAccess |
Publikationsportal JuSER |
Please use the identifier: http://dx.doi.org/10.1016/j.apgeochem.2020.104713 in citations.
A comparative study of the sorption behaviour of radium and strontium was performed on various cementitiousmaterials including crushed hardened cement pastes (HCP) and concretes as well as a synthesised calcium silicatehydrate (CSH) phase.Rd values obtained for the Ra and Sr uptake on commercial cement materials were in the range of50–380 L kg-1 and 10–30 L kg-1, respectively. No significant difference between the distribution ratios of theisotopes 226Ra and 223Ra was observed in the studied liquid to solid (L/S) ratio range, although different isothermswere determined. The Rd values for Ra were found to increase with increasing L/S ratio. The cause of thiseffect is obviously the non-linearity of the sorption isotherm, here of the convex type. In contrast, Sr uptakeseemed to be largely unaffected by variation of L/S ratios; this indicates an isotherm of almost linear type.Sorption experiments with the CSH phase confirmed the distinctive differences in the sorption behaviour betweenRa and Sr as expected, with Rd values significantly higher for Ra. Similarly, the difference between realcementitious materials and the pure CSH phase was confirmed, indicating that the sorption of alkaline earthelements is mainly due to uptake by CSH.The kinetics of Ra and Sr uptake on cementitious materials were evaluated by a set of models describing thesorption in heterogeneous systems based on different rate-controlling processes. The FD (film diffusion) model inthe case of Ra, and the ID (diffusion in inert layer) model in the case of Sr provided the best fits.The influence of temperature on the kinetics of radium sorption was studied, suggesting change in the shape ofisotherm with increasing temperature. Evaluation of sorption kinetic data yielded values of the apparent activationenergy of the uptake process.Complementary through diffusion experiments using compacted crushed HCP confirmed and extended thefindings obtained by evaluation of the batch sorption experiments performed with Ra and Sr. |