Photocatalytic degradation of azo dye using TiO2 supported on spherical activated carbon

TiO2 supported on spherical activated carbon (TiO2/SAC) was prepared through an ion-exchange method followed by a heat-treatment process. The adsorption characteristic of TiO2/SAC was evaluated using azo dye methyl orange (MO) as a target substance, and the photocatalytic degradation of MO under UV irradiation was also discussed. A synergistic effect of both the adsorption capacity of activated carbon and the photoactivity of TiO2 on the removal of MO from aqueous solution was observed. Experimental results revealed that the photocatalytic degradation of MO improved with increasing photocatalyst dosage and followed a pseudo-first order kinetic. After five-cycle runs, TiO2/SAC still exhibited relatively high photocatalytic characteristic for the degradation of MO. Besides, the prepared TiO2/SAC can be helpful in the easy separation of photocatalyst from solution after photocatalysis of MO. Furthermore, the use of liquid chromatography/mass spectrometry (LC/MS) technique, identified three intermediates as degradation products during the photocatalytic reaction of MO with TiO2/SAC.