Diffusion of humic colloids in compacted bentonite
2007 (English)In: Physics and Chemistry of the Earth, ISSN 1474-7065, E-ISSN 1873-5193, Vol. 32, no 07-jan, 477-484 p.Article in journal (Refereed) Published
Through-diffusion experiments in bentonite with humic colloids in the size range of 1-10 nm were carried out. Bentonite was compacted to 0.6-1.8 g/cm(3) dry density and equilibrated with 0.01 and 0.1 M NaClO4 solutions. Experiments with Eu(Ill) diffusing in the absence and presence of humics were run in parallel, as well as Co(ll) diffusing through compacted bentonite in the presence of hurnics. The hurnic colloid diffusion experiments were run for 60 days and the humic concentration in the outlet solutions measured at time intervals. The experimental breakthrough curves for humic substances (HS) as well as the HS, Co(II) and Eu(III) profiles in the bentonite were simulated using the finite difference based computer code ANADIFF. Regardless of the compaction and ionic strength of solutions, hurnic colloids diffused through the compacted bentonite. The effects of hurnic colloids on both Co(H) and Eu(111) sorption as well as on diffusion were significant. The apparent diffusivity (D-a) increased significantly for both Co(II) and Eu(III) when hurnic colloids were present and the distribution coefficient (K-d) values decreased.
Place, publisher, year, edition, pages
2007. Vol. 32, no 07-jan, 477-484 p.
diffusion, humic colloids, compacted bentonite, sorption, colloidal stability, radionuclide migration, transport, systems, acid, substances, stability, aquifer
IdentifiersURN: urn:nbn:se:kth:diva-16624ISI: 000246416700043ScopusID: 2-s2.0-33847754370OAI: oai:DiVA.org:kth-16624DiVA: diva2:334666
QC 201005252010-08-052010-08-05Bibliographically approved