title: Extent of sonochemical degradation and change of toxicity of a pharmaceutical precursor (triphenylphosphine oxide) in water as a function of treatment conditions.
abstract: The degradation of triphenylphosphine oxide (TPPO) in water, a toxic compound typically found in effluents from the pharmaceutical industry, by means of ultrasonic irradiation at 20 kHz has been investigated with emphasis on the effect of various parameters on conversion and acute toxicity. Experiments were carried out at liquid volumes of 50 and 80 ml, electric power outputs of 125, 187.5 and 250 W, initial TPPO concentrations of 10, 100 and 350 mg/L and temperatures of 5, 20, 35, 50 and 70 degrees C. TPPO conversion was found to increase with increasing power output and decreasing initial concentration and temperature. Measurements of dissolved total carbon showed that liquid-phase degradation by-products were more stable to ultrasonic irradiation than TPPO. Addition of t-butanol as a radical scavenger at a concentration of 1000 mg/L nearly completely suppressed TPPO degradation. Conversely, addition of radical promoters (Fe(2+) ions or H(2)O(2)) had a positive effect on degradation. Acute toxicity to marine bacteria vibrio fischeri was measured before and after ultrasonic irradiation. At the conditions employed in this study, irradiated TPPO samples were always more toxic than TPPO itself with toxicity levels being a function of treatment conditions.
authors.affiliation: Department of Chemical Engineering, University of Leeds, Clarendon Road, Leeds LS2 9JT, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Emery
authors.forename: Maria
authors.initials: M
authors.lastname: Papadaki
authors.forename: Luisa M
authors.initials: LM
authors.lastname: Freitas Dos Santos
authors.forename: Dionissios
authors.initials: D
authors.lastname: Mantzavinos
mesh_terms: D048908:Aliivibrio fischeri; D009943:Organophosphorus Compounds / Q000737:chemistry* / Q000633:toxicity; D018675:Toxicity Tests; D014465:Ultrasonics; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D018508:Water Purification / Q000379:methods*
chemical_list: D009943:Organophosphorus Compounds; D014874:Water Pollutants, Chemical; C063888:triphenylphosphine oxide