Synthesis and characterization of TiO2–montmorillonite nanocomposites and their application for removal of methylene blue

Abstract

TiO₂–montmorillonite (MMT) nanocomposites were successfully prepared via impregnating titanium tetrabutyloxide into the interlayers of MMT with the aid of supercritical ethanol, followed by hydrolysis of the precursor in water and calcination at 500 °C. The X-ray diffraction analysis and electron microscopy observation indicated that the layered structure of MMT was destroyed to some extent in the composites. High-resolution transmission electron microscopy observation showed that the TiO₂ particles with size of less than 5 nm were loaded in the exfoliated layers of MMT. The UV absorption edge of TiO₂–MMT composites showed a blue shift in the range of 325–275 nm, compared to that of TiO₂ particles. The efficiency of the TiO₂–MMT composites to remove methylene blue from its aqueous solution was investigated under UV irradiation. It was demonstrated that the as-prepared samples exhibited high efficiency to remove methylene blue due to the adsorptive capacity of MMT and the catalytic degradation ability of TiO₂ for methylene blue.