Sonocatalytic degradation of some dyestuffs and comparison of catalytic activities of nano-sized TiO2, nano-sized ZnO and composite TiO2/ZnO powders under ultrasonic irradiation

Here, a novel sonocatalyst, composite TiO(2)/ZnO powder, was prepared through the combination of nanosized TiO(2) and ZnO powders. Because of the appropriate adsorbability to organic pollutants and special crystal interphase between TiO(2) and ZnO particles, the composite TiO(2)/ZnO powder exhibits a high sonocatalytic activity under ultrasonic irradiation during the degradation of acid red B. Especially, the sonocatalytic activity of composite TiO(2)/ZnO powder with 4:1 molar proportion treated at 500 degrees C for 50 min showed obvious improvement compared with pure nano-sized TiO(2) and ZnO powders. When the experimental conditions such as 10 mg/L acid red B concentration. 1.0 g/L catalyst addition amount, pH = 7.0, 20 degrees C system temperature, 100 min ultrasonic time and 50 mL total volume were adopted, the satisfactory degradation ratio and rate were obtained. All experiments indicate that the sonocatalytic method using composite TiO(2)/ZnO powder may be a more advisable choice for the treatments of non- or low-transparent organic wastewaters in future. (C) 2008 Elsevier B.V. All rights reserved.