In this research, different origins of bentonite samples (non-treated, treated, and test) were studied by x-ray diffraction, Fourier transform spectrophotometer, viscometer, and thermogravimetry. It was observed that the major clay minerals were smectite and montmorillonite. Different band intervals were studied by Fourier transform. The weight loss regions related to the dehydration and de-hydroxylation process were determined by thermogravimetry. Kinetic parameters of the bentonite samples were determined by Arrhenius method and it was found that the activation energies of the bentonite samples were in the range of 34.1-147 kJ/mol.