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 language | English |
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Pages (from-to) | 205-210 |
Number of pages | 6 |
Journal | Journal of Colloid and Interface Science |
Volume | 437 |
DOIs | |
Publication status | Published - 1 Jan 2015 |
Externally published | Yes |
Keywords
- Nontronite clay
- Magnetic alignment
- Exfoliated clay
- Anisotropic microstructure
- Diffusion
- Permeability
- Bound water
- NMR 1D imaging
- Diffusion NMR