Thermal and chemical treatments of montmorillonite clay

Montmorillonite clay from a natural deposit was processed to remove impurities and later submitted for thermal and chemical treatments. The sample was first subjected to a thermal treatment at 400 °C, for 1 h, to remove organic components. The chemical treatment was conducted first by using an acid attack with nitric acid and sulfuric acid, then, adding sodium acetate in ethylene glycol clay dispersion, and finally the clay was dispersed in xylene with subsequent addition of silane, N-(b-aminoethyl)-g-aminopropyiltrimethylsilane. The combined thermal and chemical treatment was found to have a significant effect on the final chemical composition of the nanoclay. X-ray diffraction patterns suggested that the combined thermal and chemical treatment resulted in increased interplanar distances, thus favoring exfoliation of the clay lamellae, which was also confirmed by SEM images. Fourier transform infrared (FTIR) spectroscopy analysis suggested that the combined thermal and chemical treatment resulted in removal of water from the montmorillonite, without any modification or destruction of the clay structure. Thus, the combination of thermal and chemical treatments proposed in this work may be a promising approach to process montmorillonite intended for the production of advanced materials.