A thermal study of Zr-pillared montmorillonite

Zirconium-pillared montmorillonites have been prepared by different methods in order to investigate their effect on the physico-chemical properties of the resulting interlayered materials. It has been verified that variations in the synthesis procedure, such as concentration of the Zr solution, pH, temperature, and time of contact with the clay, affect the structure and properties of the pillared clays obtained. The thermal stability and degradation of the samples have been investigated by XRD, TA, FTIR and nitrogen adsorption-desorption isotherms. The dehydroxylation of Zr-pillared clays starts at around 523 K and ends above 1038 K. Over this whole range of temperature, the shape of the thermal curves is different. The differences have been related to the Zr content, the degree of polymerization of the Zr cations, resulting from their aging conditions, and the partial solution of the parent clay by the effect of pH of the pillaring zirconyl chloride solutions.