EFFECT OF HYDROTHERMAL AND THERMAL TREATMENTS ON THE PHYSICOCHEMICAL PROPERTIES OF MG-AL HYDROTALCITE-LIKE MATERIALS

The synthesis and characterization of hydrotalcite-like materials is described. As the time to which the samples have been submitted to a hydrothermal treatment is prolonged, a change in the Mg/Al ratio is observed, together with a more ordered structure of the species existing in the interlayer space. Calcination at increasing temperatures leads to decomposition of this compound, with the final formation of MgO and MgAl2O4. Changes taking place during these processes have been related to the decrease observed in the specific surface area of the samples upon prolonging the hydrothermal treatment, as well as its development and further decrease upon thermal treatment.