Degradation of methyl orange by composite photocatalysts nano-TiO 2 immobilized on activated carbons of different porosities

Abstract

Composite photocatalysts TiO 2 immobilized on granular activated carbons with different porosities (TiO 2/AC) were prepared by a novel approach, dip-hydrothermal method using peroxotitanate as precursor. The TiO 2/AC composites were characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and the nitrogen absorption. Their photocatalytic activity was evaluated by degradation of methyl orange (MO). The results showed that nano-TiO 2 particles of anatase type were well deposited on the activated carbon surface. The porosity of activated carbon had significant influence on the adsorption, the amount of TiO 2 deposited on the external surface of AC and the activity of composite photocatalysts. The composite TiO 2/AC made from proper mesoporosity AC exhibited higher catalytic activity than the mixture of powdered TiO 2 with AC. Furthermore, the mechanism of synergistic effect of AC adsorption and TiO 2 photocatalysis was discussed.