Efficient separation of polyester/cotton blends using a deep eutectic solvent–NaOH hybrid system for textile recycling

Abstract

To overcome the key challenges in polyester (PET)/cotton blend separation—such as difficulty in separation, high energy use, and performance degradation—a green, innovative and efficient choline chloride/ethylene glycol deep eutectic solvent–sodium hydroxide (DES–NaOH) hybrid system was developed. Benefiting from the selective structural loosening of PET fibers by DES, confirmed by Raman imaging technology, which significantly accelerates degradation under alkaline conditions, this work achieves complete degradation and recycling of PET fibers under mild reaction conditions (dissolution temperature of 98 °C, duration time of 60 min, NaOH dosage of 5% w/v, and liquor ratio of 1 : 30). Importantly, high-purity terephthalic acid was recovered through acidification, precipitation, and filtration, while cotton fibers maintained structural integrity and properties with minimal mass loss (<3%), confirming the valuable, effective and selective separation process. This work offers an innovative, environmentally friendly, and cost-effective solution to the challenge of PET/cotton blend waste recycling.