Clay properties basal spacing

The XRD patterns of zirconium sulfate pillared clays obtained after 90 hours of intercalation with different zirconium acetate concentrations using 0.5 as sulfate to Zr ratio and the same clay concentration as used earlier are presented in Fig. 5. The diffraction data show the appearance of two first order reflections. The first one is at 23.4 A for the lowest zirconium concentration and appears as a shoulder at the same distance for 0.05 mol/L concentration. The second reflection is observed at approximately 12.3 A for the lowest concentration and at 13.7 A for 0.1 mol/L zirconium acetate. The first one results from the intercalation of sulfated zirconium species. Those species are more voluminous than the non sulfated one which gives a distance spacing at only 19.6 A. The better intercalation of sulfated zirconium species at low Zr concentration is probably due to the slow progress of polycondensation reactions. This process reduces the number of different zirconium species and gives a better cristallinity of the solid. Table 2 summarizes the textural properties of samples prepared with different zirconium concentrations. The decrease of the surface area with the decrease of the Zr concentration is probably due to the increase of the sodium clay layers by comparison with the intercalated layers. The microporous volume increases when the Zr concentration decreases. The higher microporosity is due to the important basal distance of this sample. 

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