title: A novel liquid plasma AOP device integrating microwaves and ultrasounds and its evaluation in defluorinating perfluorooctanoic acid in aqueous media.
abstract: A simplified and energy-saving integrated device consisting of a microwave applicator and an ultrasonic homogenizer has been fabricated to generate liquid plasma in a medium possessing high dielectric factors, for example water. The microwave waveguide and the ultrasonic transducer were interconnected through a tungsten/titanium alloy stick acting both as the microwave antenna and as the horn of the ultrasonic homogenizer. Both microwaves and ultrasonic waves are simultaneously transmitted to the aqueous media through the tungsten tip of the antenna. The microwave discharge liquid plasma was easily generated in solution during ultrasonic cavitation. The simple device was evaluated by carrying out the degradation of the perfluorooctanoic acid (PFOA), a system highly recalcitrant to degradation by conventional advanced oxidation processes (AOPs). PFOA is 59% degraded in an aqueous medium after only 90 s of irradiation by the plasma. Intermediates were identified by electrospray mass spectral techniques in the negative ion mode.
authors.affiliation: Department of Material and Life Science, Faculty of Science and Technology, Sophia University, Tokyo, Japan. horikosi@rs.noda.tus.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Horikoshi
authors.forename: Susumu
authors.initials: S
authors.lastname: Sato
authors.forename: Masahiko
authors.initials: M
authors.lastname: Abe
authors.forename: Nick
authors.initials: N
authors.lastname: Serpone
mesh_terms: D002210:Caprylates / Q000737:chemistry / Q000528:radiation effects; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005461:Fluorine / Q000302:isolation & purification* / Q000528:radiation effects; D005466:Fluorocarbons / Q000737:chemistry / Q000528:radiation effects; D008872:Microwaves; D058626:Plasma Gases / Q000528:radiation effects*; D012996:Solutions / Q000528:radiation effects; D013010:Sonication / Q000295:instrumentation*; D018511:Systems Integration; D014867:Water / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification / Q000528:radiation effects*; D018508:Water Purification / Q000295:instrumentation*
chemical_list: D002210:Caprylates; D005466:Fluorocarbons; D058626:Plasma Gases; D012996:Solutions; D014874:Water Pollutants, Chemical; D014867:Water; D005461:Fluorine; C023036:perfluorooctanoic acid