Preparation and characterization of bimodal mesoporous montmorillonite by using single template

Bimodal mesoporous montmorillonite had been synthesized from montmorillonite and tetraethoxysilane (TEOS) by using cetyltrimethyl ammonium bromide (CTAB) as single template. The materials exhibited two kinds of mesopores: one is mesopore in interlayers of montmorillonite with mean sizes of 2.9 nm, the other is mesopore out of layers of montmorillonite with mean sizes of 3.9 nm. After being heated at 850 °C for 2 h and 10 days hydrothermal reaction at 100 °C the sample kept a high specific surface area and porous structure. At the same time, we found two mesopores had different formed condition, structure, pore size, and especially, stability. They both had good thermal stability, but the smaller pore showed more highly hydrothermal stability than the bigger one. The samples were characterized by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherms and Fourier transform infrared spectra (FT-IR). The result indicated that layered structure of montmorillonite had been present as porous wall. The stability of the as prepared mesoporous montmorillonite depended on the stability of montmorillonite present in pore wall.