Effect of ionic charge on effective diffusion coefficient in compacted sodium bentonite

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

Effective diffusion coefficients(De) in bentonite were measured as a function of ionic charge to evaluate the degree of surface diffusion and anion exclusion. The De measurements for Ni2+, Sm3+ and SeO3 2- were carried out for 1.8 Mg·m-3 by through-diffusion method. Sodium bentonite, Kunigel-V1 was used. The order of obtained De values was Sm3+>Ni2+>SeO3 2-. These De values were compared with those reported to date. Consequently, the order of De values was Cs+>Sm3+>HTO>Ni2+>anions(I-, Cl-, CO3 2-, SeO3 2-, TcO4 -, NpO2CO3 -, UO2(CO3)3 4-), showing a tendency of cations>HTO>anions. The reason that the De of Ni2+ was lower than that of HTO may be because the free water diffusion coefficient(Do) of Ni2+ is about 1/3 of that of HTO. The formation factors(FF) were in the order, Sm3+>Cs+>Ni2+>HTO>anions, indicating a possibility of surface diffusion in cations and of anion exclusion in anions. In this case, the FF of Sm3+ was approximately 5 times greater than that of HTO. However, since the Do of Sm3+ is about 1/3 of that of HTO, the De of Sm3+ may have been a little higher than that of HTO. Based on this, it is presumed that surface diffusive effect on De in bentonite is insignificant.

Original languageEnglish
Title of host publicationMaterials Research Society Symposium - Proceedings
PublisherMaterials Research Society
Pages267-274
Number of pages8
Volume608
Publication statusPublished - 2000
Externally publishedYes
EventScientific Basis for Nuclear Waste Management XXIII - Boston, MA, USA
Duration: Nov 29 1999Dec 2 1999

Other

OtherScientific Basis for Nuclear Waste Management XXIII
CityBoston, MA, USA
Period11/29/9912/2/99

Fingerprint

Bentonite
Anions
Negative ions
Sodium
Surface diffusion
Cations
Positive ions
Water

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

Cite this

Sato, H. (2000). Effect of ionic charge on effective diffusion coefficient in compacted sodium bentonite. In Materials Research Society Symposium - Proceedings (Vol. 608, pp. 267-274). Materials Research Society.

Effect of ionic charge on effective diffusion coefficient in compacted sodium bentonite. / Sato, Haruo.

Materials Research Society Symposium - Proceedings. Vol. 608 Materials Research Society, 2000. p. 267-274.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Sato, H 2000, Effect of ionic charge on effective diffusion coefficient in compacted sodium bentonite. in Materials Research Society Symposium - Proceedings. vol. 608, Materials Research Society, pp. 267-274, Scientific Basis for Nuclear Waste Management XXIII, Boston, MA, USA, 11/29/99.
Sato H. Effect of ionic charge on effective diffusion coefficient in compacted sodium bentonite. In Materials Research Society Symposium - Proceedings. Vol. 608. Materials Research Society. 2000. p. 267-274
Sato, Haruo. / Effect of ionic charge on effective diffusion coefficient in compacted sodium bentonite. Materials Research Society Symposium - Proceedings. Vol. 608 Materials Research Society, 2000. pp. 267-274
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