1. Magnetic orientation of nontronite clay in aqueous dispersions and its effect on water diffusion.
- Author
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Abrahamsson, Christoffer, Nordstierna, Lars, Nordin, Matias, Dvinskikh, Sergey V., and Nydén, Magnus
- Subjects
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NONTRONITE , *ORIENTATION (Chemistry) , *WATER , *DIFFUSION coefficients , *AQUEOUS solutions , *NUCLEAR magnetic resonance spectroscopy - 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. [ABSTRACT FROM AUTHOR]
- Published
- 2015
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