Sorption and diffusion of organic acids through clayrock: Comparison with inorganic anions

JOURNAL OF HYDROLOGY

卷:511

Article

Dagnelie, R. V. H.¹  Descostes, M.^1,2  Pointeau, I.¹  Klein, J.¹  Grenut, B.¹  Radwan, J.¹  Lebeau, D.³  Georgin, D.⁴  Giffaut, E.⁵ 

[1] CEA, Lab Radionuclides Migrat Measurements & Modelling, DEN DANS DPC SECR, F-91191 Gif Sur Yvette, France

[2] Univ Evry, CNRS, CEA, UMR 8587, Evry, France

[3] CEA, Lab Radiolysis & Organ Matter, DEN DANS DPC SECR, F-91191 Gif Sur Yvette, France

[4] CEA, Lab Labelling 14C, DSV IBITEC S SCBM, F-91191 Gif Sur Yvette, France

[5] ANDRA, DRD TR, F-92298 Chatenay Malabry, France

关键词: Organic;    Sorption;    Diffusion;    Clay;    EDTA;    Phthalate;   

DOI  :  10.1016/j.jhydrol.2014.02.002

来源: Elsevier

【 摘 要 】

Organic complexing species are known to affect radionuclide mobility in the environment. The migration behaviour of several organic ligands was evaluated in the context of a proposed French radioactive waste repository in the Callovo-Oxfordian clayrock formation (COx). This study focuses on four anthropogenic acids (ethylenediaminetetraacetate, isosaccharinate, phthalate, oxalate) that are used in the nuclear fuel cycle or that occur as hydrosoluble degradation products of waste materials. Batch sorption and diffusion experiments were performed with COx clayrock samples using C-14-labelled radiotracers. The observed effective diffusion coefficients were low (D-e similar to 1-6 x 10(-12) m(2) s(-1)), an order of magnitude lower than that of tritiated water in the same material, and roughly the same as values for inorganic anions such as I-, Cl- and SO42-. The observed correlation of D-e with molecular mass, M-1/3, differs significantly from that observed for cations. The organic ligands displayed significant affinity for the COx clayrock, with distribution ratios measured in batch experiments, R-d = 1-30 L kg(-1), which are much higher than usually observed for anionic species. While this result was confirmed by through-diffusion experiments, the K-d values obtained by fitting diffusion modelling were significantly lower than those measured in the batch experiments. (c) 2014 Elsevier B.V. All rights reserved.

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