Simple enzymatic depolymerization process based on rapid ball milling pretreatment for high-crystalline polyethylene terephthalate fibers

• Published in: Bioresource technology 2025-01, Vol.416, p.131759, Article 131759
• Main Authors: Zhou, Yu, Zhang, Jinxu, Zheng, Yunxin, Lin, Wei, You, Shengping, Wang, Mengfan, Su, Rongxin, Qi, Wei
• Format: Article
• Language: English
• Subjects: Ball milling; Crystallization; Enzymatic-depolymerization process; High crystallinity; Hydrolysis; Phthalic Acids - chemistry; Polyester fiber; Polyesters - chemistry; Polyethylene terephthalate; Polyethylene Terephthalates - chemistry; Polymerization
• ISSN: 0960-8524; 1873-2976; 1873-2976
• DOI: 10.1016/j.biortech.2024.131759

[Display omitted] •A simple enzymatic hydrolysis process based on ball milling for high crystallinity waste PET fiber.•Ball milling has triple advantages of short-time, mild reaction conditions, and chemical-free.•Fast 30-min milling achieved a 23.8-fold increase in TPA yield with nearly 100 % purity.•Amorphization and roughening combined to enhance the PET enzymatic hydrolysis. The high crystallinity (30 %–50 %) of discarded polyester textile waste limits the industrialization of its clean enzymatic depolymerization. In this study, a simple process based on ball milling pretreatment was developed to achieve effective enzymatic hydrolysis of high-crystalline polyester fiber. Ball milling was selected for its short, mild, and chemical-free process, which achieved a remarkable 23.8-fold (60.9 %) increase in terephthalic acid (TPA) yield from waste polyethylene terephthalate (PET) degradation, along with high TPA purity in the released soluble compounds. Just 30 min of ball milling at room temperature induced polyester amorphization, resulting in polyester with 12 % lower crystallinity compared with untreated polyester (51 %), while simultaneously increasing the surface roughness of polyester, thereby enhancing the efficiency of enzymatic hydrolysis. The simple process for effective enzymatic-depolymerization of waste polyester fiber developed in this study has potential industrial applications.