Mesoporous TiO2-Montmorillonite Composite Prepared Under Soft Hydrothermal Conditions

Abstract

This paper examines mesoporous TiO₂-montmorillonite composites synthesized by hydrothermally activated impregnation (115°C, 0.5 – 5.0 h) of mechanochemically and thermally activated montmorillonite with titanium polyhydroxy complexes. The materials were characterized using x-ray diffraction (XRD), infrared (IR) spectroscopy, low-temperature nitrogen adsorption/desorption, scanning electron microscopy (SEM), electrophoretic light scattering, and energy-dispersive spectroscopy (EDS). The duration of hydrothermal treatment significantly influenced the crystallite size of titanium dioxide and the anatase-to-rutile phase ratio, as well as the surface morphology and textural properties of the composites. Photometric analysis was used to evaluate the adsorption capacity and photocatalytic activity of the composites toward Rhodamine B as a model dye. Overall, hydrothermal treatment substantially enhanced the photocatalytic activity of the composites. However, prolonged treatment duration resulted in a decline in this effect. The obtained composites exhibited a pronounced synergistic effect of adsorption and photocatalysis in removing Rhodamine B from a highly concentrated (40 mg/L) aqueous solution.