A7 Kinetic Analysis of Ultrasonic Degradation Process of Methylene Blue

Abstract

Ultrasound is an attractive technology for the degradation of hazardous organic compounds in water. However, the effects of ultrasonic frequency on degradation rate constants were not investigated quantitatively. In this study, the ultrasonic degradation process of methylene blue was investigated. This study focused on the effects of ultrasonic frequency and power on the degradation rate constant, and the apparent rate constants were estimated based on time dependence of methylene blue concentration assuming pseudo-first-order kinetics. The apparent degradation rate constant at 490 kHz was about 15 times larger than that at 22.8 kHz in the condition of same ultrasonic power. The influence of frequency on sonochemical degradation in this study agrees with the previous study and suggests a relationship between the degradation rate constant and SEKI value. It is also found that there is a linear relationship between the apparent degradation rate constant and ultrasonic power. We proposed a simple model for estimating the apparent degradation rate constant of methylene blue based on ultrasonic power and SEKI value.