A STUDY OF ORIENTATION OF ADSORBED WATER MOLECULES ON MONTMORILLONITE CLAYS BY PULSED NMR

The study of clay water systems by pulsed nuclear magnetic resonance reveals that natural as well as synthetic clays have associated with them a certain amount of oriented water. Direct experimental evidence of oriented water between natural clay platelets is observed for montmorillonite at room temperature. Doublet splittings in the NMR spectra indicate that the water molecules are preferentially oriented by the clay platelets. The occurrence of the doublet splitting was found to be affected by both particle size and temperature. Experimental evidence indicates that the transverse relaxation process above room temperature is not grossly affected by paramagnetic centers arising from the natural iron content of the clay lattice. Although it is more difficult to observe the doublet splitting in samples with a high iron content, these paramagnetic centers do not preclude its occurrence. © 1969.