Integration of Adsorption and Photocatalytic Degradation of Methylene Blue Using TiO 2 Supported on Granular Activated Carbon
Abstract
An integrated process was investigated for the degradation of methylene blue (MB); it was based on the combination of adsorption and photocatalysis. A granular activated carbon (C) was considered for adsorption, which involved TiO 2 as a photocatalyst (TiO 2/ C ). The TiO 2/ C was directly obtained by an impregnation method using TiCl 3; it was also calcined under air atmosphere at 500∘C (TiO 2/ C -500). These materials were characterized by TGA, BET, SEM, EDS mapping, SEM-EDS, and their pH PZC were measured. The results obtained showed that activated carbon (C) exhibited the best performances in terms of adsorption. The photocatalytic activity on the degradation of MB in aqueous solution under UV irradiation was tested and compared to that of TiO 2 anatase (TiO2A) and a mixture of carbon with TiO 2 (C―TiO 2). TiO 2/ C -500 catalyst was found to be more active than the other catalysts; the C with high surface area provided sites for adsorption, allowing the migration of the dye to the surface of TiO 2. A synergistic effect between C and TiO 2 was shown, which enhanced the photocatalytic activity by retarding the recombination of photogenerated electron–hole pairs, improving light absorption. © 2016, King Fahd University of Petroleum & Minerals.