Perturbation induced by EDTA on HDO, Br- and EuIII diffusion in a large-scale clay rock sample

R.V.H. Dagnelie (1, 2) , P. Arnoux (1) , J. Radwan (1) , D. Lebeau (1) , P. Nerfie (1) , C. Beaucaire (1)

1 DPC - Département de Physico-Chimie
2 L3MR - Laboratoire de Mesures et Modélisation de la Migration des Radionucléides

Clay rocks are widely studied in the context of waste landfill leachates or as geological barriers for nuclear waste management. The release of organic co-contaminants by wastes may alter clay rocks, depending on the ratio between the volume of wastes and the mass of rock. In this work, a 10 mM EDTA plume was injected in a large-scale clay rock sample with a low V/m ratio (<< 1.0 L kg- 1) close to environmental conditions. The chemical perturbation was monitored for 450 days, as well as its effect on HDO, Br-, and EuIII diffusion. Alteration of carbonates and iron-rich phases was evidenced in addition to the decrease of tracer concentration. Negatively charged complexes of EDTA and Eu are slightly adsorbed on minerals surface and display a desorption hysteresis. Transport parameters including diffusion anisotropy of HDO, Br, and EDTA complexes are estimated. Results are discussed with emphasis on determination of the mechanisms governing such a perturbation and the corresponding transitory state.

Mots clés: Clay; EDTA; anisotropy; Large-scale; Diffusion Sorption Clay EDTA anisotropy Large-scale; Diffusion; Sorption

Domaines: Chimie

R.V.H. Dagnelie, P. Arnoux, J. Radwan, D. Lebeau, P. Nerfie, et al.. Perturbation induced by EDTA on HDO, Br- and EuIII diffusion in a large-scale clay rock sample. Applied Clay Science, 2015, 105-106, pp.142-149. ⟨10.1016/j.clay.2014.12.004⟩. ⟨hal-04240835⟩