Enzymatic bleaching of cotton fibres with laccase/mediator systems combined with oxygen and ozone

Abstract

Enzymes should be used in every step of pretreatment of cotton textiles in order to minimize energy and water consumption while keeping the effluent control within the tolerable standards. It has been investigated whether enzymatic bleaching of cotton textiles could be replaced with hydrogen peroxide bleaching, which is a water and energy consuming step. In this study, fungal laccase, laccase moderator systems and also oxygen and ozone feed to these systems have been experimented. The initial whiteness of the desizied fabric before bleaching was 49 stensby degree. This value did not increase over 51 stensby degree by use of enzyme and also enzyme moderator systems. Oxygen and ozone feeding at a gas flow rate of 1000 ml/min and ozone concentration of 32 mg/min have been conducted in order to increase whiteness. Oxygen feed did not have a considerable effect and whiteness degrees raised up to only 51 stensby degree, however, ozone feed enhanced to raise the whiteness of the fabric upto 68 stensby degree by enzyme alone and 70 stensby degree by enzyme moderator systems.