title: Sonochemical and hydrodynamic cavitation reactors for laccase/hydrogen peroxide cotton bleaching.
abstract: The main goal of this work is to develop a novel and environmental-friendly technology for cotton bleaching with reduced processing costs. This work exploits a combined laccase-hydrogen peroxide process assisted by ultrasound. For this purpose, specific reactors were studied, namely ultrasonic power generator type K8 (850 kHz) and ultrasonic bath equipment Ultrasonic cleaner USC600TH (45 kHz). The optimal operating conditions for bleaching were chosen considering the highest levels of hydroxyl radical production and the lowest energy input. The capacity to produce hydroxyl radicals by hydrodynamic cavitation was also assessed in two homogenizers, EmulsiFlex®-C3 and APV-2000. Laccase nanoemulsions were produced by high pressure homogenization using BSA (bovine serum albumin) as emulsifier. The bleaching efficiency of these formulations was tested and the results showed higher whiteness values when compared to free laccase. The combination of laccase-hydrogen peroxide process with ultrasound energy produced higher whiteness levels than those obtained by conventional methods. The amount of hydrogen peroxide was reduced 50% as well as the energy consumption in terms of temperature (reduction of 40 °C) and operating time (reduction of 90 min).
authors.affiliation: IBB-Institute for Biotechnology and Bioengineering, Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057 Braga, Portugal.
authors.forename: Idalina
authors.initials: I
authors.lastname: Gonçalves
authors.forename: Madalena
authors.initials: M
authors.lastname: Martins
authors.forename: Ana
authors.initials: A
authors.lastname: Loureiro
authors.forename: Andreia
authors.initials: A
authors.lastname: Gomes
authors.forename: Artur
authors.initials: A
authors.lastname: Cavaco-Paulo
authors.forename: Carla
authors.initials: C
authors.lastname: Silva
mesh_terms: D000818:Animals; D001203:Ascomycota / Q000201:enzymology; D032561:Cotton Fiber; D055772:Green Chemistry Technology; D057446:Hydrodynamics; D006861:Hydrogen Peroxide / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D042845:Laccase / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000737:chemistry; D013718:Tensile Strength; D014465:Ultrasonics
chemical_list: D012710:Serum Albumin, Bovine; D006861:Hydrogen Peroxide; D042845:Laccase
keywords: Bleaching; Cavitation; Homogenization; Hydroxyl radicals; Sonication