title: Identification of active sonochemical zones in a triple frequency ultrasonic reactor via physical and chemical characterization techniques.
abstract: Coupling multiple frequencies in ultrasonic systems is one of the highly desired area of research for sonochemists, as it is known for producing synergistic effects on various ultrasonic reactions. In this study, the characteristics of a hexagonal-shaped triple frequency ultrasonic reactor with the combination frequencies of 28, 40 and 70kHz were studied. The results showed that uniform temperature increment was achieved throughout the reactor at all frequency combinations. On the other hand, sonochemiluminescence emission and degradation rate of Rhodamine B varies throughout different areas of the reactor, indicating the presence of acoustic 'hot spots' at certain areas of the reactor. Also, coupling dual and triple frequencies showed a decrease in the hydroxyl radical (OH) production, suggesting probable wave cancelling effect in the system. The results can therefore be served as a guide to optimize the usage of a triple frequency ultrasonic reactor for future applications.
authors.affiliation: Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: T Joyce
authors.initials: TJ
authors.lastname: Tiong
authors.affiliation: Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Derick K L
authors.initials: DK
authors.lastname: Liew
authors.affiliation: Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Ramona C
authors.initials: RC
authors.lastname: Gondipon
authors.affiliation: Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Wong
authors.affiliation: Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Yuen Ling
authors.initials: YL
authors.lastname: Loo
authors.affiliation: Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
authors.forename: Matthew S T
authors.initials: MS
authors.lastname: Lok
authors.affiliation: Department of Chemical and Environmental Engineering, University of Nottingham Malaysia Campus, Jalan Broga, 43500 Semenyih, Selangor, Malaysia. Electronic address: Sivakumar.Manickam@nottingham.edu.my.
authors.forename: Sivakumar
authors.initials: S
authors.lastname: Manickam
keywords: Cavitation; Characterization; Degradation; Reactor; Triple frequency; Ultrasound