Recovery of high-quality terephthalic acid from waste polyester textiles via a neutral hydrolysis method

As a consequence of the extensive use of polyethylene terephthalate (PET) in the textile industry, a significant amount of PET waste is generated. To achieve environmental remediation and sustainable development, it is imperative to transform the PET waste into valuable chemical raw materials. One promising approach to managing this waste is neutral hydrolysis, which converts PET to terephthalic acid (PTA) and ethylene glycol (EG) and is environmentally friendly. However, the current technology suffers from difficulties in decolorization and purification of the PTA. Herein, we implemented a new closed-loop route for recycling waste polyester textiles, which comprises of the pre-decolorization of textile samples, neutral hydrolysis of decolorized waste polyester textiles and purification of the PTA products by reduced-pressure sublimation. Using this method, waste polyester textiles that are picked up from waste bins having various colors and compositions were successfully hydrolyzed to form PTA with a purity of up to 99.9%. The yield of the recovered PTA reached 95.1%, and the whiteness value (L*) was up to 99.9. The regenerated PET (r-PET) obtained through repolymerization of the recycled PTA exhibited similar properties to those of PET derived from petroleum-based PTA.