Powder XRD-pattern of montmorillonite and different
cation-exchanged montmorillonite samples are shown in Fig. 1. The
d001 basal spacing from the XRD patterns was used to examine the
structural changes that occurred during the preparation of the cationexchanged
clay (Stathi et al., 2009). The d001-values for the basal reflection
at 2θ=9.1° in Zn2+ and Fe3+-exchanged montmorillonite samples
were almost similar to the parent montmorillonite (9.63 Å), indicating