Acid strength at clay mineral surfaces
Abstract
The interactions of ,{1 3+ -montmorillonite, Na+ - montmorillonite and
Na+ -kaolinite with selected Hammett indicators have been reinvestigated.
The use of a series of indicators with different acid strengths, Ho,
to determine the activity of protons on the clay surface was basid on the
assumption that the activity of H+ on the clay surface is equivalent to
activity in solution.
The results show that A13+- montmorillonite had the hiehest acid
strength, especially after drying at 1lfc. Na+-kaolinite had Ih" lo*r"rt
acid strength, at two moisture levels: befirre washing with ethanol and
u{"l g1lporation of this alcohol. At all moisture levels the acid strength of A1'* -montmorillonite was greater than that of either Nai -
montmorillonite or Na+ - kaolinite.
Citation
Kenya Journal of Science and Technology Series A (1986) 7(l): 25-33Publisher
Department of Soil Science, University of Nairobi