title: Application of power ultrasound for azo dye degradation.
abstract: Power ultrasound of 850 kHz at 60, 90 and 120 W was used for the degradation of industrial azo dyes Acid Orange 5 and 52, Direct Blue 71, Reactive Black 5 and Reactive Orange 16 and 107. The results show that power ultrasound is able to mineralize azo dyes to non-toxic end products, which was confirmed by respiratory inhibition test of Pseudomonas putida. All investigated dyes have been decolorized and degraded within 3-15 h at 90 W and within 1-4 h at 120 W, respectively. Mass spectrometric investigations show, that hydroxyl radicals attack azo dyes by simultaneous azo bond scission, oxidation of nitrogen atoms and hydroxylation of aromatic ring structures. A volumetric scale-up showed a correlation between the energy input and the absolute amount of degraded dye. Up to an energy input of about 90 W no enzymatic deactivation of laccase was observed which might be helpful for a simultaneous action of sonochemical and enzymatic treatments.
authors.affiliation: Faculty 09, Institute of Chemical Engineering and Plant Design, University of Applied Sciences Cologne, Betzdorfer Strasse 2, Cologne D-50679, Germany. astrid.rehorek@fh-koeln.de
authors.forename: Astrid
authors.initials: A
authors.lastname: Rehorek
authors.forename: Michael
authors.initials: M
authors.lastname: Tauber
authors.forename: Georg
authors.initials: G
authors.lastname: Gübitz
mesh_terms: D001391:Azo Compounds / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D001673:Biodegradation, Environmental; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D007477:Ions / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D042845:Laccase / Q000378:metabolism; D008163:Luminescent Measurements; D015394:Molecular Structure; D016958:Pseudomonas putida / Q000187:drug effects; D014465:Ultrasonics; D014733:Vibrio / Q000187:drug effects; D014865:Waste Disposal, Fluid / Q000379:methods
chemical_list: D001391:Azo Compounds; D004396:Coloring Agents; D007477:Ions; D042845:Laccase