Comparison of Sonolysis, Photolysis, and Photosonolysis for the Degradation of Organic Matter

Document Type : Research Paper


1 Assist. Prof., Faculty of Health, Kurdistan University of Medical Sciences

2 Assist. Prof., Faculty of Public Health, Tehran University of Medical Sciences

3 Faculty Member, Dept. of Environmental Health, Kurdistan University of Medical Sciences


Phenol is one of the most common compounds found in the effluents of many industries such as petroleum refining and petrochemicals, pharmaceuticals, pesticides, paint and dye industries, organic chemicals manufacturing, etc. Due to the high toxicity of phenol, the contamination of bodies of water with this chemical is a serious problem for the environment and human health. In this study, the sonochemical, photochemical, and photosonochemical degradation of phenol in an aqueous solution were investigated. The sonochemical and photochemical experiments were carried out using a bath sonicator (500 W) working at 35 and 130 kHz frequencies and a 400W medium pressure UV lamp. Experiments were performed at initial concentrations varying from 1 to 100 mg L-1. The effects of such parameters as pH, initial phenol concentration, and oxidation period have been determined. Results showed that the effects of ultrasound wave for phenol oxidation were mainly due to hydroxyl radical production during cavitation-induced water decomposition. However, low rates of sonochemical destruction of phenol in water solution obtained. In the sonochemical process, phenol underwent degradation at a faster rate at 130 kHz than 35 kHz. Besides, it was shown that reaction rates involving hydroxyl radicals (hydrogen peroxide formation and phenol oxidation) had a maximum value at higher frequencies. The best yield was observed at 130 kHz for phenol degradation perhaps due to the greater availability of hydroxyl radical on the outer surface of cavitation bubbles. It was found that the rate of photochemical degradation of phenol was higher than sonochemical destruction. Also, the results showed that the combination of ultrasound wave and ultraviolet irradiation was considerably more effective than either ultrasound or ultraviolet light alone. Thus, based on the results of this study, the synergistic action of ultrasound and ultraviolet light is confirmed. This may be the result of three different oxidative processes: direct photochemical action, high frequency sonochemistry, and reaction with ozone (produced by UV irradiation of air). The results of the study showed that the degradation of phenol was increased by decreasing both pH value and phenol concentration in all the processes used.


1- Lifka, J., Ondruschka, B., and Hofmann, J. (2003). “The use of ultrasound for the degradation of pollutants in water: Aquasonolysis- A Review.” Engineering in Life Sciences, 3(6), 253-262.
2- Sawyer, C.N., McCarty, P.L., and Parkin, G.E. (2000). Chemistry for environmental engineering, 4th Ed., Tata McGraw-Hill, New Delhi.
3- Nemerow, N.L. (1991). Industrial and hazardous waste treatment, 2nd Ed., Van Nostrand Reinhol, New York.
4- Hoffman, M.R. (1996). “Application of ultrasonic irradiation for the degradation of chemical contaminants in water.” Ultrasonics Sonochemistry, 3 (3), 163-172.
5- Bien, B. J., Kempa, E.S., and Bien J.D. (1997). “Influence of ultrasonic field on structure and parameters of sewage sludge for dewatering process.” Wat. Sci. Tech., 36 (4), 287-291.
6- Naffrechoux, E., Chanoux, S., Petrier, J., and Suptil, J. (2000). “Sonochemical and photochemical oxidation of organic matter.” Ultrasonics Sonochemistry, 7 (4), 255-259.
7- APHA, AWWA, WEF. (1998). Standard methods for the examination of water and wastewater, 9th  Ed., Washington.
8- Lesko, T.M. (2004). “Chemical effects of acoustic cavitation.” Ph.D. Thesis, California Institute of Technology, Pasadena, California.
9- Lorimer, J. P. (2002). Applied solochemistry, VELEY VCH VERLAG GMBH Co., weiheim.
10- Wu, C., Liu, X., Wei, D., Fan, J., and Wang L. (2001). “Photosonochemical degradation of phenol in water.” Water Research, 35(16), 3927-3933.
11- Mahamuni, N.N., and Pandit, A.B. (2006). “Effect of additives on ultrasonic degradation of phenol.” Ultrasonics Sonochemistry, 13(2),165-174.
12- Alnaizy, R., and Akgerman, A. (2000). “Advanced oxidation of phenolic compounds.” Advances in Environmental Research, 4 (3), 233-244.