Effect of sonication on ZnO and ZnO-Fe catalyst for colour and COD removal from Methylene Blue solution

Textile and cosmetics industries are among the industries which produce huge volume of dyes wastewater. Photocatalysis is of the methods that effectively treating dye wastewater. Semiconductor such as zinc oxide (ZnO) is one of the photocatalyst which is widely used in photocatalysis treatment method. In this research, removal of chemical oxygen demand (COD) and colour from Methylene Blue (MB) solution using ZnO were compared with ZnO doped with Fe. In addition, ultrasonic cavitation was also applied during the preparation of the catalyst. The catalysts were successfully synthesized through sol-gel method. By comparing all catalysts, sonocatalyst ZnO doped Fe produced the highest efficiency for colour removal. During the experiments, the colour removal from MB solution with 10 ppm and 30 ppm concentration were 99.65% and 51.3% respectively. This study concluded that the presence of ultrasonic cavitation during the catalyst preparation did change the physical and chemical characteristics of ZnO doped Fe. As a result, the catalyst worked better during the treatment system to remove colour from MB solution.