Polyethylene terephthalate (PET) fibers are characterized by exceptional mechanical strength, and textiles blended with cotton fibers combine both comfort and durability, showcasing widespread use in daily applications. However, improper disposal of discarded polyester-cotton textiles has resulted in severe environmental pollution, necessitating urgent and effective mitigation strategies. Enzymatic recycling of textiles offers superior environmental benefits and holds greater potential for industrial applications than alternative recycling methods. This study aims to explore a large-scale solution for the treatment of waste textiles, particularly addressing the challenge of resource recovery from polyester-cotton blended fabrics. An innovative enzymatic depolymerization process has been developed to achieve the recovery of high-purity terephthalic acid monomers. Experiments were conducted on three different textile blends with polyester-to-cotton ratios of 65/35, 70/30, and 80/20, and the influences of different colors on the process were investigated. Initially, the textiles were pretreated through mechanical grinding, which was followed by depolymerization of cotton fibers with commercial cellulase. The crystallinity of PET in the textiles was reduced through a rapid heating and cooling process. Subsequently, the PET was depolymerized by the engineered PET hydrolase. The results demonstrated that after decolorization and separation of terephthalic acid (TPA) from the reaction system, the monomer recovery rates for the three textile blends (65/35, 70/30, and 80/20) reached 90%, 91%, and 92%, respectively. Characterization analysis by nuclear magnetic resonance (NMR) confirmed that the purity of the recovered TPA was greater than 99%. In conclusion, the fully enzymatic recycling process developed in this study shows considerable promise for large-scale industrial applications and is anticipated to significantly advance the adoption and development of enzymatic recycling technologies for PET in industrial processes.
Phthalic Acids/chemistry* ; Polyesters/chemistry* ; Textiles ; Cotton Fiber ; Polyethylene Terephthalates/chemistry* ; Cellulase/chemistry* ; Recycling/methods* ; Polymerization

OBJECTIVETo study correlations of polychlorinated biphenyls (PCBs), DIOXIN, and polybrominated diphenyl ethers (PBDE) with thyroid stimulating hormone(TSH) in children, and assess the impact on children's health.

METHODSThree hundred and sixty nine children aged from 6 to 8, including 195 from Luqiao, the computer E-waste recycling area, and 174 from Longyou, the control area, were selected for this investigation to elucidate the correlation of PCBs, DIOXIN, and PBDE with TSH in children's blood samples. The children had a physical examination and their blood levels of PCBs, DIOXIN, PBDE, and TSH were detected after sample collection.

RESULTSIn the E-waste recycling area, the contents of PCBs, PBDE, DIOXIN, and TSH in the blood samples of children were 484.00 ± 84.86 ng·g(-1) lipid weight, 664.28 ± 262.38 ng·g(-1) lipid weight, 26.00 ± 19.58 ng·g(-1) lipid weight and 1.88 ± 0.42 μIU/mL (serum) respectively, while in the control area, the PCBs, PBDE, DIOXIN, and TSH contents were 255.38 ± 95 ng·g(-1) lipid weight, 375.81 ± 262.43 ng·g(-1) lipid weight, 39.64 ± 31.86 ng·g(-1) lipid weight, and 3.31±1.04 μIU/mL respectively.

CONCLUSIONThe health status of children in the control area are better than that in the contaminated area. Among children who are exposed to persistent organic pollutants, the pollutant content increases significantly in their serum, and the distribution of TSH levels in their bodies are also affected.

Child ; China ; Dioxins ; blood ; chemistry ; Electronic Waste ; Environmental Pollutants ; blood ; chemistry ; Female ; Halogenated Diphenyl Ethers ; blood ; chemistry ; Humans ; Male ; Polychlorinated Biphenyls ; blood ; chemistry ; Recycling ; Refuse Disposal ; methods ; Thyrotropin ; blood