From Waste Garments to Recoverable Fibres: A Mechano-Enzymatic Strategy for Post-Consumer Textile Recycling

Enzymatic recycling offers a promising route for recovering fibres from textile waste; however, processes developed predominantly on single-fabric model substrates have rarely been validated using authentic post-consumer garments. In this study, 110 post-consumer children’s garments (15.6 kg) were collected and characterised, revealing a fibre composition of 84.0% cotton, 12.8% polyester, and 3.2% other fibres. Cellulases produced by Aspergillus niger and Trichoderma reesei were first evaluated using a bead-assisted hydrolysis approach. Although efficient textile disintegration was achieved for an in-house woven polycotton fabric (84% cotton, 16% polyester), resulting in separation yields of up to 92%, the same process performed poorly on post-consumer cotton garments, with more than 78% of the textile structure remaining intact after treatment. These results identified substrate accessibility as a major limitation to the enzymatic processing of real textile waste. To address this challenge, an optimised mechano-enzymatic process incorporating intermittent grinding during hydrolysis was developed. A grinding duration of 4 min combined with 4 h of hydrolysis produced the highest separation yield, and the integrated treatment consistently outperformed grinding alone by 12–14% across all hydrolysis times investigated. The optimised process was subsequently validated using twenty post-consumer garments comprising ten cotton-rich textiles (98–100% cotton) and ten cotton–polyester blends containing 35–85% cotton. Separation yields of 91.7–99.7% (mean 97.1%) and recoverable fibre yields of 85.6–97.4% (mean 90.7%) were achieved across all garments. ATR-FTIR spectroscopy, optical microscopy, and thermogravimetric analysis of model cotton and polycotton fabrics before and after treatment demonstrated selective hydrolysis of cellulose while preserving polyester fibres. Cellulose-associated FTIR bands decreased by 10–98%, whereas characteristic polyester ester and aromatic bands remained unchanged. Microscopy further confirmed the physical separation of intact polyester filaments from liberated cotton fibres. Overall, the results demonstrate that substrate accessibility is a critical barrier to enzymatic textile recycling and show that intermittent grinding substantially enhances fibre liberation from post-consumer textiles. The recovered fibre fractions represent a promising feedstock for textile recycling; however, detailed assessment of compositional purity and fibre quality is required to determine their suitability for closed-loop applications.