title: The sonolytic destruction of methyl tert-butyl ether present in contaminated groundwater.
abstract: Ultrasonic irradiation in the presence of ozone was used to efficiently eliminate methyl tert-butyl ether (MTBE) from groundwater. The sonolytic degradation of MTBE was investigated in three different reactor configurations and frequencies: vibrating-plate reactor (VPR, 358 kHz), near-field acoustical processor (NAP 20 and 16 kHz), and radial-tube resonator (RTR. 20 kHz). The sonochemical reactors can be ordered in terms of their efficiency with respect to the degradation of MTBE in the following way: VPR > RTR > NAP. The higher elimination rates of MTBE in groundwater by combined ultrasound-ozone systems are attributed to the effective conversion of ozone to the OH radical, even in the presence of high alkalinity. Carbonate radicals, which were formed from the oxidation of bicarbonate by hydroxyl radicals, are shown to react with MTBE via a hydrogen-atom abstraction pathway. Methyl-tert-butyl ether was also rapidly eliminated from the groundwater underlying a major intemational airport by direct chemical oxidation with a mixture of hydrogen peroxide and ozone.
authors.affiliation: Department of Engineering and Applied Science, Harvard University, Cambridge, Massachusetts, USA.
authors.forename: Hui-Ming
authors.initials: HM
authors.lastname: Hung
authors.forename: Joon-Wun
authors.initials: JW
authors.lastname: Kang
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hoffmann
mesh_terms: D002273:Carcinogens / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008738:Methyl Ethers / Q000032:analysis*; D016877:Oxidants / Q000737:chemistry; D010083:Oxidants, Photochemical / Q000737:chemistry; D010084:Oxidation-Reduction; D010126:Ozone / Q000737:chemistry; D012989:Soil Pollutants; D014465:Ultrasonics; D014873:Water Pollutants; D014876:Water Pollution / Q000517:prevention & control*
chemical_list: D002273:Carcinogens; D008738:Methyl Ethers; D016877:Oxidants; D010083:Oxidants, Photochemical; D012989:Soil Pollutants; D014873:Water Pollutants; C043243:methyl tert-butyl ether; D010126:Ozone; D006861:Hydrogen Peroxide