title: Ultrasonic pilot-scale reactor for enzymatic bleaching of cotton fabrics.
abstract: The potential of ultrasound-assisted technology has been demonstrated by several laboratory scale studies. However, their successful industrial scaling-up is still a challenge due to the limited pilot and commercial sonochemical reactors. In this work, a pilot reactor for laccase-hydrogen peroxide cotton bleaching assisted by ultrasound was scaled-up. For this purpose, an existing dyeing machine was transformed and adapted by including piezoelectric ultrasonic devices. Laboratory experiments demonstrated that both low frequency, high power (22 kHz, 2100 W) and high frequency, low power ultrasounds (850 kHz, 400 W) were required to achieve satisfactory results. Standard half (4 g/L H2O2 at 90 °C for 60 min) and optical (8 g/L H2O2 at 103 °C for 40 min) cotton bleaching processes were used as references. Two sequential stages were established for cotton bleaching: (1) laccase pretreatment assisted by high frequency ultrasound (850 kHz, 400 W) and (2) bleaching using high power ultrasound (22 kHz, 2100 W). When compared with conventional methods, combined laccase-hydrogen peroxide cotton bleaching with ultrasound energy improved the whitening effectiveness. Subsequently, less energy (temperature) and chemicals (hydrogen peroxide) were needed for cotton bleaching thus resulting in costs reduction. This technology allowed the combination of enzyme and hydrogen peroxide treatment in a continuous process. The developed pilot-scale reactor offers an enhancement of the cotton bleaching process with lower environmental impact as well as a better performance of further finishing operations.
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal.
authors.forename: Idalina
authors.initials: I
authors.lastname: Gonçalves
authors.affiliation: Centre de Recerca i Innovació de Catalunya, C/Vìctor Pradera 45, 08940 Cornellá de Llobregat, Barcelona, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Herrero-Yniesta
authors.affiliation: Centre de Recerca i Innovació de Catalunya, C/Vìctor Pradera 45, 08940 Cornellá de Llobregat, Barcelona, Spain.
authors.forename: Iratxe
authors.initials: I
authors.lastname: Perales Arce
authors.affiliation: Centre de Recerca i Innovació de Catalunya, C/Vìctor Pradera 45, 08940 Cornellá de Llobregat, Barcelona, Spain.
authors.forename: Monica
authors.initials: M
authors.lastname: Escrigas Castañeda
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal. Electronic address: artur@deb.uminho.pt.
authors.forename: Artur
authors.initials: A
authors.lastname: Cavaco-Paulo
authors.affiliation: CEB - Centre of Biological Engineering, University of Minho, 4710-057 Braga, Portugal; 3B's Research Group, Biomaterials, Biodegradables and Biomimetics, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, S. Cláudio de Barco, 4806-909 Taipas, Guimarães, Portugal. Electronic address: cmpsilva@ceb.uminho.pt.
authors.forename: Carla
authors.initials: C
authors.lastname: Silva
mesh_terms: D000818:Animals; D001203:Ascomycota / Q000201:enzymology; D003116:Color; D003362:Cost-Benefit Analysis; D032561:Cotton Fiber; D006861:Hydrogen Peroxide / Q000737:chemistry; D042845:Laccase / Q000378:metabolism*; D010865:Pilot Projects; D013696:Temperature; D014465:Ultrasonics / Q000191:economics / Q000295:instrumentation / Q000379:methods*
chemical_list: D006861:Hydrogen Peroxide; D042845:Laccase
keywords: Bleaching; Cotton; Laccase; Pilot-scale reactor; Ultrasound