Magnetic orientation of nontronite clay in aqueous dispersions and its effect on water diffusion

Christoffer Abrahamsson*, Lars Nordstierna, Matias Nordin, Sergey V. Dvinskikh, Magnus Nydén

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)

Abstract

The diffusion rate of water in dilute clay dispersions depends on particle concentration, size, shape, aggregation and water-particle interactions. As nontronite clay particles magnetically align parallel to the magnetic field, directional self-diffusion anisotropy can be created within such dispersion. Here we study water diffusion in exfoliated nontronite clay dispersions by diffusion NMR and time-dependant 1H-NMR-imaging profiles. The dispersion clay concentration was varied between 0.3 and 0.7 vol%. After magnetic alignment of the clay particles in these dispersions a maximum difference of 20% was measured between the parallel and perpendicular self-diffusion coefficients in the dispersion with 0.7 vol% clay. A method was developed to measure water diffusion within the dispersion in the absence of a magnetic field (random clay orientation) as this is not possible with standard diffusion NMR. However, no significant difference in self-diffusion coefficient between random and aligned dispersions could be observed.

Original languageEnglish
Pages (from-to)205-210
Number of pages6
JournalJournal of Colloid and Interface Science
Volume437
DOIs
Publication statusPublished - 1 Jan 2015
Externally publishedYes

Keywords

  • Nontronite clay
  • Magnetic alignment
  • Exfoliated clay
  • Anisotropic microstructure
  • Diffusion
  • Permeability
  • Bound water
  • NMR 1D imaging
  • Diffusion NMR

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