Recycling and valorization of waste colored polyester through a zero-waste approach

The resource recovery of waste polyester textiles is of great significance for sustainable development. This work proposes an integrated strategy for the full-component recovery and high-value utilization of waste colored polyester, which effectively solves the industrial problems of high recovery cost and low resource utilization. Ethylene glycol (EG) was used as both decolorization and reaction medium for camouflage polyester fabric. EG could be recycled in a closed-loop system, greatly reducing raw material consumption and production cost. Meanwhile, the synchronous recovery of dyes and polyester monomers realized the full utilization of multi-component resources. The decolorized fabric showed a whiteness of 63.9% and a decolorization rate of 93.2%. The recovered dyes exhibited excellent dyeing performance. The decolorized polyester was further converted into high-purity BHET monomer via glycolysis, which was used to synthesize waterborne polyurethane (WPU) and improve the hydrophobicity of the material. When coated on cotton fabric, the WPU coating increased the water contact angle from 0° to 122°, and improved tensile strength and wear resistance by 2-3 and 3-4 times, respectively. All recycled products including EG, recovered dyes, and BHET-based WPU can be reused in the textile industry, providing a feasible technical route for the construction of an atom-economical circular system.