title: Experimental and numerical investigation of the effect of liquid temperature on the sonolytic degradation of some organic dyes in water.
abstract: This paper presents a comprehensive experimental and numerical investigation of the effects of liquid temperature on the sonochemical degradation of three organic dyes, Rhodamine B (RhB), Acid orange 7 (AO7) and Malachite green (MG), largely used in the textile industry. The experiments have been carried out for an ultrasonic frequency of 300 kHz. The obtained experimental results were discussed using a new approach combining the results of single-bubble event and the number of active bubbles. The single-bubble event was predicted using a model that combines the bubble dynamics with chemical kinetics occurring inside a bubble during the strong collapse. The number of active bubbles was predicted using a method developed in our previous work. The experiments showed that the degradation rate of the three dyes increased significantly with increasing liquid temperature in the range 25-55°C. It was predicted that the main pathway of pollutants degradation is the attack by OH radicals. The simulations showed that there exists an optimum liquid temperature of about 35°C for the production of OH inside a bubble whereas the number of active bubbles increased sharply with the rise of the liquid temperature. It was predicted that the overall production rate of OH increased with increasing liquid temperature in the range 25-55°C. Finally, it was concluded that the effect of liquid temperature on the sonochemical degradation of the three dyes in aqueous phase was controlled by the number of active bubbles in the range 35-55°C and by both the number of bubbles and the single bubble yield in the range 25-35°C.
authors.affiliation: Laboratory of Environmental Engineering, Department of Process Engineering, Faculty of Engineering, Badji Mokhtar - Annaba University, P.O. Box 12, 23000 Annaba, Algeria; Department of Chemical Engineering, Faculty of Process Engineering, University of Constantine 3, Constantine, Algeria. Electronic address: s.merouani@yahoo.fr.
authors.forename: Slimane
authors.initials: S
authors.lastname: Merouani
authors.affiliation: Laboratory of Environmental Engineering, Department of Process Engineering, Faculty of Engineering, Badji Mokhtar - Annaba University, P.O. Box 12, 23000 Annaba, Algeria.
authors.forename: Oualid
authors.initials: O
authors.lastname: Hamdaoui
authors.affiliation: Laboratory of Environmental Engineering, Department of Process Engineering, Faculty of Engineering, Badji Mokhtar - Annaba University, P.O. Box 12, 23000 Annaba, Algeria.
authors.forename: Zineb
authors.initials: Z
authors.lastname: Boutamine
authors.affiliation: Laboratory of Applied Chemistry and Materials Technology, University of Oum El-Bouaghi, P.O. Box 358, 04000 Oum El Bouaghi, Algeria.
authors.forename: Yacine
authors.initials: Y
authors.lastname: Rezgui
authors.affiliation: Laboratory of Applied Chemistry and Materials Technology, University of Oum El-Bouaghi, P.O. Box 358, 04000 Oum El Bouaghi, Algeria.
authors.forename: Miloud
authors.initials: M
authors.lastname: Guemini
keywords: ()OH radical; Liquid temperature; Numerical simulations; Organic dyes; Sonochemical degradation