Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The bentonite barrier: microstructural aspects on colloid filtration and radiation effects on bentonite colloid stability
KTH, School of Chemical Science and Engineering (CHE), Chemistry.
2009 (English)Licentiate thesis, comprehensive summary (Other academic)
Place, publisher, year, edition, pages
Stockholm: KTH , 2009. , 47 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2009:4
National Category
Other Basic Medicine
Identifiers
URN: urn:nbn:se:kth:diva-10313ISBN: 978-91-7415-234-0 (print)OAI: oai:DiVA.org:kth-10313DiVA: diva2:214638
Presentation
2009-03-13, K1, Teknikringen 56, Stockholm, 10:00 (English)
Supervisors
Available from: 2009-05-07 Created: 2009-05-06 Last updated: 2010-10-14Bibliographically approved
List of papers
1. Colloid diffusion in compacted bentonite: microstructural constraints
Open this publication in new window or tab >>Colloid diffusion in compacted bentonite: microstructural constraints
2010 (English)In: Clays and clay minerals, ISSN 0009-8604, E-ISSN 1552-8367, Vol. 58, no 4, 532-541 p.Article in journal (Refereed) Published
Abstract [en]

In Sweden and in many other countries, a bentonite barrier will be used in the repository for spent nuclear fuel. In the event of canister failure, colloidal diffusion is a potential, but scarcely studied mechanism of radionuclide migration through the bentonite barrier. Column and in situ experiments are vital in understanding colloid diffusion and in providing information about the microstructure of compacted bentonite and identifying cut-off limits for colloid filtration. This study examined diffusion of negatively charged 2-, 5-, and 15-nm gold colloids in 4-month diffusion experiments using MX-80 Wyoming bentonite compacted to dry densities of 0.6–2.0 g/cm3. Breakthrough of gold colloids was not observed in any of the three diffusion experiments. In a gold-concentration profile analysis, colloid diffusion was only observed for the smallest gold colloids at the lowest dry density used (estimated apparent diffusivity Da 5x10–13 m2/s). The results from a microstructure investigation using low-angle X-ray diffraction suggest that at the lowest dry density used, interlayer transport of the smallest colloids cannot be ruled out as a potential diffusion pathway, in addition to the expected interparticle transport. In all other cases, with either greater dry densities or larger gold colloids, compacted bentonite will effectively prevent diffusion of negatively charged colloids due to filtration.

Keyword
Colloid Filtration • Compacted Bentonite, Gold Colloids, Diffusion, Microstructure, Nuclear Waste Disposal
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-25247 (URN)10.1346/CCMN.2010.0580408 (DOI)000289446500008 ()2-s2.0-78149471771 (Scopus ID)
Note
QC 20101013. Tidigare titel: "Colloid Permeability of Compacted Bentonite: Microstructural Constraints".Available from: 2010-10-13 Created: 2010-10-13 Last updated: 2017-12-12Bibliographically approved
2. Free Porosity of Compacted Saturated MX-80 Bentonite and Na-montmorillonite as a Function of Dry Density
Open this publication in new window or tab >>Free Porosity of Compacted Saturated MX-80 Bentonite and Na-montmorillonite as a Function of Dry Density
2009 (English)Article in journal (Refereed) Submitted
National Category
Other Chemistry Topics
Identifiers
urn:nbn:se:kth:diva-25250 (URN)
Note
QS 20120315Available from: 2010-10-14 Created: 2010-10-14 Last updated: 2012-03-15Bibliographically approved
3. Effects of gamma-irradiation on the stability of colloidal Na+-Montmorillonite dispersions
Open this publication in new window or tab >>Effects of gamma-irradiation on the stability of colloidal Na+-Montmorillonite dispersions
2009 (English)In: Applied Clay Science, ISSN 0169-1317, E-ISSN 1872-9053, Vol. 43, no 1, 86-90 p.Article in journal (Refereed) Published
Abstract [en]

In many concepts for final storage of spent nuclear fuel bentonite will be used as an engineered barrier, mainly due to its inertness, plasticity and ability to retard transport of radionuclides by adsorption. In the event of water-bearing fractures making contact with the bentonite barrier, generation and transport of colloidal particles will strongly depend on groundwater composition and the surface properties of the colloidal particles. The bentonite barrier will unavoidably be exposed to ionizing radiation from the spent nuclear fuel but very little is known about effects of ionizing radiation on bentonite concerning colloidal stability. In this work we have studied the effect of gamma-radiation on the stability of dilute colloidal Na+-montmorillonite dispersions using a Cs-137 gamma-source (doses of 0-53.2 kGy). Aggregation kinetics and sedimentation experiments revealed significant radiation effects, evident as increased colloid stability. The only rationale for this is a gamma-radiation induced increase in surface potential. The effects appeared to depend on the Na+-montmorillonite concentration in the irradiated dispersions, indicating that the change in surface potential is induced by aqueous radiolysis products.

Keyword
Radiation effects, gamma-radiation, Montmorillonite, Colloid stability, Bentonite
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-18118 (URN)10.1016/j.clay.2008.07.004 (DOI)000262658000013 ()2-s2.0-57649085839 (Scopus ID)
Note
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2017-12-12Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Holmboe, Michael
By organisation
Chemistry
Other Basic Medicine

Search outside of DiVA

GoogleGoogle Scholar

isbn
urn-nbn

Altmetric score

isbn
urn-nbn
Total: 323 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf