Al2O3/ZrO2 nanocomposites were synthesized by growth of semiconductor ZrO2 onto Al2O3 nanoparticles by a facile sol-gel method using tragacanth gum as a natural gel. Ultrasonic technique was applied for the coating of ZrO2 onto Al2O3 during the production process of nanostructures. XRD data confirmed the formation of Al2O3/ZrO2 nanocomposites. The synthesized Al2O3/ZrO2 was evaluated for photocatalytic activity through degradation of Reactive Blue 222(RB222) and Reactive Yellow 145(RY145) dyes in aqueous solution under visible irradiation. Influence of some parameters such as initial dye concentration, catalyst loading and irradiation duration on the degradation of dyes was investigated as well as the optimum conditions were obtained. The results showed that the removal efficiency of a 20 mg/L (50 mL) dye solution reached 91.4 % for RB222 and 94.6 % for RY145 only in 60 min of reaction duration with 0.04 g of Al2O3/ZrO2 as catalyst. The dyes degradation was monitored by using UV-Vis spectroscopy.
