An innovative method for the removal of impurities and bleaching of cotton fabrics by UV/H₂O₂/pectinase: Intrinsic mechanisms and treatment effects

The high energy consumption and pollution associated with traditional cotton fabric treatment have become increasingly serious concerns; thus, in this study, a synergistic cotton fabric treatment based on Novozymes pectinate lyase (NPL) scouring/ultraviolet light-mediated catalytic (UV/H 2 O 2 ) bleaching was innovatively proposed. This study investigated the degradation mechanisms of impurities in cotton fabrics, concluding that the oxidative bleaching reaction of morin follows first-order kinetics; in the UV/H 2 O 2 /NPL system, pectin degradation occurs through the β-elimination of NPL and oxidation by free radicals. Under optimized conditions—254 nm UV irradiation, 8 g⋅L −1 NPL, 30 g⋅L −1 H 2 O 2 , pH 9, and one-side irradiation for 45 min. The fabric whiteness could reach 79.04 %，but the fiber damage was severe, manifested by a 40 % decrease in polymerization and strength. After adjusting the process parameters, adjust the UV wavelength to 302 nm and add 6 g⋅L −1 of the activator (NOBS), whiteness of the fabric was about 76.7 % and strength retention rate was 96.38 %. This method overcomes the shortcomings of traditional pretreatment processes for cotton fabrics, under low temperature and alkaline conditions, low-strength damaged fabrics can be obtained, providing a new strategy for developing environmentally friendly pre-treatment processes for cotton fabrics.