Fast pyrolysis of waste textiles: Product distribution, formation of hazardous by-products, and resource recovery pathways

Textile consumption has been continuously increasing, posing significant challenges for waste management and disposal. Pyrolysis offers significant potential for recovering resources from non-degradable textiles (e.g., polyester). However, comprehensive studies on product distribution and the release of hazardous components across diverse textile types remain limited, which restricts the development of high-value resource recovery strategies and leads to potential environmental and health risks. This study systematically investigated the fast pyrolysis (550 °C) characteristics of five pure textiles-cotton (C), wool (W), nylon (N), polyester (T), rayon (R)-and one mixed textile (MT). The results revealed distinct product profiles for different textile types. Cotton-derived bio-oil exhibited high content (83.61 %) of light hydrocarbons (<C10), making it suitable for use as liquid fuel after simple acid removal. Wool pyrolysis generated complex bio-oil requiring secondary cracking. Synthetic fabrics (N, T, R) produced bio-oils with substantial corrosive carboxylic acids (e.g., benzoic acid), necessitating esterification pretreatment for fuel use. MT pyrolysis yielded nitrogen-rich bio-oil (74.77 % N-compounds) containing 37.35 % caprolactam, highlighting its value as a chemical feedstock but requiring carbon black separation from the particulate matter (PM). PM analysis identified viscosity-driven formation in cotton and tar/soot dominance in synthetics. This study provides critical insights into tailoring pyrolysis protocols to specific textile wastes, thereby advancing sustainable resource recovery while mitigating corrosion and pollution risks associated with hazardous by-products.