抄録
Recently the various kinds of advanced oxidation processes (AOPs) using ozone, hydrogen peroxide, super or semi critical water, photocatalyst, ultrasound and so on have been developed for waste water treatment polluted by organic compounds. Since application of only one AOP process has a limited effect, combinations of AOPs were suggested due to their combined effects. As one of the promising processes, sonophotocatalysis, which is the combination of sonolysis and photocatalysis, have been proposed for degradation of organic pollutants and water decomposition. In this research, the authors propose the new sonophotocatalytic process, which uses the ultraviolet light emitting devices dispersed in the reactor as light sources for photocatalysis. The device is composed of a piezoelectric element and ultraviolet light emitting diodes (UV-LEDs). The piezoelectric element generates electricity due to resonating with ultrasonic vibration and the UV-LEDs become luminous. By using such devices, it will not be necessary to supply electricity for light source. In addition, the dispersed devices can supply light in dead spaces inside a reactor. The experiments of methylene blue decomposition were conducted by using the ultrasonic irradiation, the photocatalyis, the sonophotocatalysis using fixed UV-LEDs and the new sonophotocatalysis. The results showed that the new method accelerated the decomposition but there were little differences between the fixed type sonophotocatalysis and new methods under the present experimental conditions.
