title: Understanding acoustic cavitation for sonolytic degradation of p-cresol as a model contaminant.
abstract: Many modern techniques exist for the degradation of organic pollutants in water. Numerous treatment processes which utilize the formation of hydroxyl radicals for oxidation of pollutants have been studied thoroughly. In this study, a three pronged approach has been used to characterize and understand the effect of two distinct acoustic frequencies (37 kHz and 1 MHz) on cavitation behavior. Correlation of this behavior with sonolysis of a target phenol pollutant is described. Hydroxyl radical capture, hydrophone, and microelectrode studies in this work show that megasonic frequencies are more effective for generation of hydroxyl radicals and stable cavitation events than ultrasonic frequencies. UV absorption and fluorescence measurements confirm that the combination of ultrasonic sonolysis with a Fenton reagent achieved complete degradation of p-cresol at 50 mg/L in about 30 min. Cost estimates have been made for different sonication processes and compared with traditional advanced oxidation processes.
authors.affiliation: Materials Science and Engineering, 1235 E James E Rogers Way, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Balachandran
authors.affiliation: Materials Science and Engineering, 1235 E James E Rogers Way, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Zach
authors.initials: Z
authors.lastname: Patterson
authors.affiliation: Materials Science and Engineering, 1235 E James E Rogers Way, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Pierre
authors.initials: P
authors.lastname: Deymier
authors.affiliation: Chemical and Environmental Engineering, 1133 E James E Rogers Way, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Shane A
authors.initials: SA
authors.lastname: Snyder
authors.affiliation: Materials Science and Engineering, 1235 E James E Rogers Way, University of Arizona, Tucson, AZ 85721, USA. Electronic address: manishk@email.arizona.edu.
authors.forename: Manish
authors.initials: M
authors.lastname: Keswani
mesh_terms: D003408:Cresols / Q000032:analysis*; D004867:Equipment Design; D006861:Hydrogen Peroxide / Q000737:chemistry; D017665:Hydroxyl Radical / Q000032:analysis; D007501:Iron / Q000737:chemistry; D010084:Oxidation-Reduction; D013010:Sonication / Q000295:instrumentation / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D003408:Cresols; C045076:Fenton's reagent; D014874:Water Pollutants, Chemical; C032538:4-cresol; D017665:Hydroxyl Radical; D006861:Hydrogen Peroxide; D007501:Iron
keywords: Acoustic cavitation; Fenton's reagent; Hydroxyl radicals; Sonolysis; p-cresol