Green Chemical Approaches for Upcycling Waste Polyester/Cotton Blends into Antibacterial Cellulose Films and Recovered TPA

ABSTRACT The rapid development of the textile industry has led to massive disposal of waste polyester/cotton blended fabrics via landfilling or incineration, causing severe environmental pollution and resource waste. To achieve high‐value recycling, this work proposes a green chemical approach for efficient separation and upcycling of polyester and cotton components. A deep eutectic solvent (ZnCl 2 /H 3 PO 4 /H 2 O) dissolved cotton, leaving polyester intact. The cellulose solution, rich in Zn 2+ ions, was reinforced with bacterial cellulose (BC) to form a composite film. Subsequent NaOH treatment and thermal decomposition enabled in situ synthesis of zinc oxide (ZnO), yielding an antibacterial regenerated cellulose film (Cellulose/BC/ZnO). Antibacterial tests showed that the inhibition zones against E. coli, S. aureus , and P. aeruginosa were 2.6 ± 0.2, 3.0 ± 0.2, and 2.0 ± 0.2 mm, respectively, confirming the antibacterial efficacy of zinc oxide. For separated polyester fibers, a bio‐based solvent system (DMI/EG/KOH) facilitated alkaline hydrolysis, depolymerizing PET into high‐purity terephthalic acid (TPA). Structural and thermal analyses (FT‐IR, XRD, TGA) verified TPA recovery. Molecular dynamics simulations elucidated solvent‐polymer interactions at the electronic level, offering mechanistic insights into cellulose dissolution and PET depolymerization. This work provides a sustainable strategy for textile waste upcycling, expands applications of regenerated cellulose films in biomedicine, and promotes closed‐loop polyester recycling.