Halloysite from Szeg, Hungary was analyzed for phase purity using X-ray diffraction techniques. The halloysite was purified by sedimentation and size fractionated to <20 μm. Three hundred milligrams were treated with 30 cm3 of 7.2 M potassium acetate solution. The sample was shaken for 80 hours in a constant temperature bath at ambient temperature. The excess solution on the clay was removed by centrifugation. The potassium acetate-intercalated halloysite was allowed to dry in air before analysis.

Figure 1 shows X-ray diffraction patterns of potassium acetate-intercalated halloysite heated to 250 °C and cooled to 25 °C under nitrogen.  Figure 2 is a graph showing crystallite size as a function of temperature upon heating and cooling.  Figure 3 is Raman spectra of the hydroxyl-stretching region of potassium acetate intercalated halloysite sequentially heated, as labeled. Figure 4 shows the variation of the peak position (a) bandwidth (b) of the hydroxyl-stretching bands of potassium acetate-intercalated halloysite as a function of temperature. Figure 5 shows Raman spectra of the hydroxyl deformation and C-C stretching region of potassium acetate-intercalated halloysite after heating to the prehydroxylation temperature and cooling to 25 °C.  Figure 6 is Raman spectra of the hydroxyl deformation and C-O stretching region of potassium acetate-intercalated halloysite after heating to the prehydroxylation temperature and cooling to 25 °C.  Figure 7 shows the variation of the relative intensities of the two CO2− symmetric stretching modes and the two acetate bonded inner surface hydroxyl stretching vibrations as a function of temperature.  Figure 8 Raman spectra of the OCO bending region of potassium acetate-intercalated halloysite after heating to the predehydroxylation temperature and cooling to 25 °C.