Sustainable Keratin Fibre Generation: Dye Removal, Extraction, and Spinning of Wool Waste for Fashion and Textile Applications

This study investigates dye removal, wool dissolution, and keratin extraction from wool waste samples initially dyed with synthetic Bemacid E dyes. Dimethyl sulfoxide (DMSO) was selected for dye extraction due to its mild impact on dye structure; however, operational challenges led to the adoption of Decrolin (C2H6O6S2Zn), a reducing agent commonly used in textile bleaching. Decrolin’s dye removal was confirmed by UV-Vis analysis but showed potential re-oxidation effects over time, indicating incomplete dye extraction. Fourier Transform Infrared (FTIR) analysis revealed that while treatments affected sample coloration, keratin structures remained largely intact, although slight conformation changes were observed. The study examined wool dissolution using various reduction-based systems, finding that elevated temperatures (up to 80°C) enhanced dissolution efficacy without significant keratin degradation. Dialysis and filtration further purified keratin solutions, producing variable concentrations dependent on treatment. SDS-PAGE analysis highlighted different molecular weights among keratin extracts, suggesting optimal extraction conditions for high-molecular-weight proteins, which are crucial for forming strong keratin filaments. A wet spinning process was used to fabricate keratin-polyvinyl alcohol (PVOH) filaments. Tensile testing showed that methylene diphenyl diisocyanate (MDI) cross-linking significantly enhanced filament strength, achieving a tenacity suitable for potential commercial application. The study concludes that while keratin fibres from wool waste display promising tenacity, further adjustments are needed to improve elongation, balancing strength and flexibility for industrial viability. Future research should refine extraction methods and optimize spinning parameters to enhance fibre properties.