Effects of dissolved gases and pH on sonolysis of 2,4-dichlorophenol.
Ultrasonic degradation of 2,4-dichlorophenol (2,4-DCP) has been studied under oxygen, air, argon, and nitrogen in aqueous solutions for a liquid temperature of 20 degrees C at 489 kHz. The degradation rate increases significantly in the presence of O2, and argon, whereas it remains the lowest under nitrogen, for which a competitive reaction model has been proposed for its non-exponential decay. Experiments have been also performed at three different pHs, 11.0, 6.3, and 2.0. The significant degradation has been achieved at pH 6.3 under O2 (0.86 x 10(-3) s(-1)), which is 1.9 and 4 times higher than acidic (pH 2.0), and basic (pH 11.0) conditions, respectively. The degradation rates have decreased in the order O2 > Ar > air > N2 irrespective of pH.
Uddin
Helal
H
Department of Applied Physics and Chemistry, University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 182-8585, Japan.
Hayashi
Shigeo
S
D000465:Algorithms; D002733:Chlorophenols / Q000737:chemistry* / Q000528:radiation effects; D002851:Chromatography, High Pressure Liquid; D005740:Gases / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000737:chemistry; D012996:Solutions; D013056:Spectrophotometry, Ultraviolet; D014465:Ultrasonics
D002733:Chlorophenols; D005740:Gases; D012996:Solutions; C004762:2,4-dichlorophenol; D010100:Oxygen