Effect of Particle Addition on Degradation Rate of Methylene Blue in an Ultrasonic Field

Abstract

Ultrasound has been found to be an attractive advanced technology for the degradation of hazardous organic compounds in water. In addition, the sonochemical reaction is enhanced by particle addition. However, the enhancement mechanism of particle addition has not been investigated well, because ultrasound enhances not only chemical reactions but also mass transfer. In this study, the ultrasonic degradation of methylene blue was carried out, and the effects of the ultrasonic irradiation condition on the degradation rate were investigated. The effect of ultrasonic frequency on the improvement of degradation by particle addition was also investigated. The order of degradation rate with frequency was the same as the tendency of sonochemical efficiency value obtained using KI oxidation dosimetry method (SE KI). The degradation process of methylene blue was intensified by particle addition, and the degradation rate increased with increasing amount of particle addition. The enhancement of degradation rate by particle addition was influenced by both ultrasonic frequency and type or diameter of particles.

Measurement of pressure amplitude of ultrasonic standing wave based on method of obtaining optical wavefront using phase retrieval

“…The coefficients c 1 and c 2 are obtained from the power series regression of the retrieved optical phase ¾h calc ðx; 0Þ. 20) and (21). However, «C 2 « has unclear local maximum points because it is difficult to measure the optical phase precisely around the pressure antinode.…”

“…The measurement of low-frequency ultrasonic standing waves is important in various fields. For example, a sonoreactor, which is applied to the degradation of chemical compounds [21][22][23][24][25] and soil washing, 26,27) often employs standing waves. The optimization of the acoustic field is essential because the acoustic pressure dominates the efficiency of the sonochemical treatment.…”

Effect of Particle Addition on Ultrasonic Degradation Reaction Rate

“…In our previous study, the ultrasonic degradation of methylene blue in the absence and presence of TiO2 or Al 2 O 3 particles for various frequencies was carried out [21]. The enhancement of degradation rate by particle addition was influenced by both ultrasonic frequency and type or diameter of particles.…”

Synergistic effect of microwave plasma and ultrasonic wave on decomposition of organic compounds in water

“…[15][16][17][18] It is also reported that the ultrasonic wave irradiation in water can decompose organic compounds such as phenol or carbon tetrachloride [19][20][21][22][23] that are resistant to conventional water treatment techniques. The organic decomposition mechanism by the ultrasonic wave has been discussed and the formation of acoustic cavitation, which includes the formation, growth, and implosive collapse of bubbles in a liquid, [24][25][26][27] is now considered to play an important role in the formation of chemically reactive species such as hydrogen atoms, hydrogen peroxide, and hydroxyl radicals, [28][29][30][31][32][33][34] and the resultant organic decomposition. It has also been reported that the combination of an ultrasonic wave and UV irradiation shows a synergistic effect.…”