Figure 5: Evidence of Cs⁺ adsorption in aluminized vermiculite layers.

Qualitative comparison of experimental diffraction patterns obtained after different sample treatments for original vermiculite (a) and vermiculite altered under acidic conditions for 383 h (b) and 1055 h (c). Blue: Na⁺-saturated specimen (Na⁺-sat.). Black: Cs⁺-saturated sample (Cs⁺-sat.). Red: after NH₄⁺-exchange of Cs⁺-saturated specimen (Cs⁺/NH₄⁺-sat.). The limited modification in the intensity of the peak at ~11 Å between Cs⁺ saturation and Cs⁺/NH₄⁺ saturation of the samples indicates the presence of immobile Cs⁺ in the vermiculite layers. The change in intensity of the peak at ~14 Å after the different treatments provides evidence of the presence of a remaining layer charge in hydroxy-interlayered layers with reversible adsorption sites for Cs⁺.