The Iranian bentonite, sampled from the Siah-Khane region was washed and heat treated at different temperatures (400, 600, 800 and 1000°C). The prepared samples were characterized to evaluate their physical and chemical properties by X- ray powder diffraction (XRD), X-ray fluorescence analysis (XRF) and N2-sorption analyzes. In addition, the cation exchange capacity of them was determined by methylene blue test. The results showed that the bentonite possess a mesoporous structure with a high surface area (83 m2/g). In addition, the sample which calcined at 400°C presented the highest cation exchange capacity.
