The effect of thermal treatment on the properties of hydroxy-Al and hydroxy-Ga pillared montmorillonite and beidellite

The pillaring process of montmorillonite and beidellite with Al and Ga polymers has been studied using XRD, IR, Al, Ga, and Si MAS NMR, TGA, TEM, N adsorption and chemical analyses. The Al adsorption maximum for montmorillonite is close to 5.5 mEqAl/g clay, whereas the maximum for Ga is higher. Basal spacings of Both Ga- and Al-pillared clays vary between 16.7 and 18.8 Å. Freeze-drying of pillared products followed by calcination yielded more regular pillared structures. Pillaring montmorillonite increased the BET surface area from 35 m/g to 350 m/g mainly by the creation of micropore