Sonocatalytic treatment of baker's yeast effluent

Baker's yeast effluent is a major source of pollution with a high organic load and dark colour. It can be treated by using advanced oxidation processes (AOPs). AOPs, such as ultrasonic irradiation, are ambient temperature processes involving the generation of free radicals. We have investigated sonocatalytic treatment of baker'syeasteffluent by using ultrasound. TiO2-ZnOcompositeswere used as sonocatalysts to increase the efficiency of the ultrasonic irradiation. The TiO2/ZnO composite was prepared by two different methods. Ultrasonic irradiation or mechanical stirring was used to prepare the TiO2-ZnO composite, and an ultrasonic homogenizer with a 20 kHz frequency was used to treat the baker's yeast effluent. We studied the effects of several parameters, including the molar ratio of TiO2/ZnO, calcination temperature, calcination time and catalyst amount, on the sonocatalytic treatment of the effluent. According to the results, the decolorization ratewas 25% when using the composite TiO2/ZnOprepared at a 4: 1 molar ratio and treated at 700 degrees for 60 min, and the optimum catalyst amount was 0.15 g/l.