Sonochemical degradation

Teo KC, Xu Y, Yang C (2001) Sonochemical degradation of toxic halogenated organic compounds. Ultrason Sonochem 8 241-246... 

Petrier C, Lamy MF, Francony A, Benahceene A, David B, Renaudin V, Gondreson N (1994) Sonochemical degradation of phenol in dilute aqueous solutions comparison of the reaction rates at 20 and 487 kHz. J Phys Chem 98 10514—10520... 

P Christian, Dominick C (2001) The sonochemical degradation of aromatic and chloroaro-matic contaminants. In Mason TJ and Tiehm A (eds) Advances in sonochemistry ultrasound in environmental protection, Elsevier 6 102-103... 

Francony A, Petrier C (1996) Sonochemical degradation of carbon tetrachloride in aqueous solution at two frequencies 20 kFIz and 500 kHz. Ultrason Sonochem 3(2) S77... 

Nagata Y, Nakagawa M, Okuno H, Mizukoshi Y, Yim B, Maeda Y (2000) Sonochemical degradation of chlorophenols in water. Ultrason Sonochem 7 115-120... 

Minero C, Lucchiari M, Vione D, Maurino V (2005) Fe(III)-enhanced sonochemical degradation of methylene blue in aqueous solution. Environ Sci Technol 39(22) 8936-8942... 

Sonochemical Degradation of Phenol in the Presence of Inorganic Catalytic Materials... 

Entezari MH, Petrier C, Devidal P (2003) Sonochemical degradation of phenol in water a comparison of classical equipment with a new cylindrical reactor. Ultrason Sonochem 10 103-108... 

Sivasankar T, Moholkar VS (2009) Mechanistic approach to intensification of sonochemical degradation of phenol. Chem Eng J 149 57-69... 

Zheng W, Maurin M, Tarr MA (2005) Enhancement of sonochemical degradation of phenol using hydrogen atom scavengers. Ultrason Sonochem 12 313-317... 

Bapat PS, Gogate PR, Pandit AB (2008) Theoretical analysis of sonochemical degradation of phenol and its chloro-derivatives. Ultrason Sonochem 15 564—570... 

Kenji O, Kazuya I, Yoshihiro Y, Hiroshi B, Rokuro N, Yasuaki M (2005) Sonochemical degradation of azo dyes in aqueous solution a new heterogeneous kinetics model taking into account the local concentration of OH radicals and azo dyes. Ultrason Sonochem... 

Result The sonochemical degradation of phenol is less than either p-aminophe-nol or p-nitrophenol. However, the sonochemical degradation of p-aminophenol is more than that of p-nitrophenol. This difference in the degradability of individual organic moieties can be understood / explained as below. 

Sonochemical Degradation of Carbofuran in a Parallel-Plate Near-Field Acoustical Processor , Ulrike Pfalzer and Inez Hua, 20th Annual Midwest Environmental Chemistry Workshop, November 9, 1997, Indiana University, Bloomington, IN. 

Hua, I., Hochemer, R.H., Hoffmann, M. R., The Sonochemical Degradation of/>-Nitrophenol in a Parallel-Plate Near-Field Acoustical Processor, Environmental Science and Technology,... 

Ultrasonic irradiation has also been employed for chemical remediation of water but the mode of sonochemical degradation of organic compounds in aqueous solution depends upon their physical and chemical properties. This is because there are two ways in which the cavitation bubble can function. In the case of volatile chemicals which enter the bubble, destruction occurs through the extreme conditions generated on collapse. In the case of chemicals remaining in the aqueous phase the bubble acts as a source of radicals (H, HO and HOO ) which enter the bulk solution and react with pollutants. 

Pettier et al. (1992) studied the sonochemical degradation of pentachlorophenol in aqueous solutions saturated with different gases at 24 °C. Ultrasonic irradiation of solutions saturated with air or oxygen resulted in the liberation of chloride ions and mineralization of the parent compound to carbon dioxide. When the solution was saturated with argon, pentachlorophenol completely degraded to carbon monoxide and chloride ions, in aqueous solution, pentachlorophenol was degraded by ozone at a reaction rate of >3.0 x 10 /M-sec at pH 2.0 (Hoigne and Bader, 1983). 

De Visscher, A., Van Eenoo, P., Drijvers, D., and Van Langenhove, H. Kinetic model for the sonochemical degradation of monocyclic aromatic hydrocarbons in aqneons solntion, J. Phys. Chem., 100(28) 11636-11642, 1996. 

Destaillats, H Hoffmann, MR Wallace, HC. Sonochemical degradation of polutants. In Tarr MA, editor. Chemical degradation methods for wastes and pollutants - environmental and industrial applications. New York Marcel Dekker 2003 201-233. 

Schwikkard, G.W., Winship, S.J., and Buckley, C.A., Sonochemical Degradation of Hydantoin Chemicals, Project Report, Department of Chemical Engineering, University of Natal, Republic of South Africa, 1990. 

The choice of the saturation gas is critical. When Ar and Kr were sparged in water irradiated at 513 kHz, an enhancement in the production of OH radicals of between 10% and 20%, respectively, was observed, compared with 02-saturated solutions [22]. The higher temperatures achieved with the noble gases upon bubble collapse under quasi-adiabatic conditions account for the observed difference. Because the rate of sonochemical degradation is directly linked to the steady state concentration of OH radicals, the acceleration of those reactions is expected in the presence of such background gases. The use of ozone as saturation gas (in mixtures with 02) provided new reaction pathways in the gas phase inside the bubbles, which also increase the measured reaction rates (see Sect. IV.G.l). 

The sonochemical degradation rates for several aromatic compounds of environmental interest such as phenol [15], nitrobenzene [52], and nitrophenol [18,52,53] have been determined recently. In the three cases, two frequencies were analyzed (20 and 500 kHz), with the treatment being more efficient at the higher frequency. The same tendency as chlorophenol was observed a... 

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