Catalytic Fabric Recycling: Glycolysis of Blended PET with Carbon Dioxide and Ammonia

Abstract

The ubiquity of nonbiodegradable polyethylene terephthalate (PET) materials has led to significant waste management challenges. Although PET plastics can be recycled, blended materials, such as PET/cotton fabrics, complicate the recycling process due to the labile glycosidic bonds in cotton. In this study, we present a practical and scalable approach for recycling of PET and PET/cotton interwoven fabrics via catalytic glycolysis with ammonium bicarbonate (NH 4 HCO 3 ), which decomposed to ammonia, carbon dioxide, and water. This catalytic approach outperformed conventional acid/base and metal catalysis in selectively recovering and upcycling cotton-based materials. We demonstrated the large-scale recovery of textile from blended fabrics (up to 213 g), showcasing the advantages of traceless catalysis using ammonia and CO 2 from ammonium bicarbonate. Owing to our metal-free reaction conditions, high-purity bis(hydroxyethyl)terephthalate (BHET) was obtained which was thermally repolymerized to PET. Through thermal analysis, kinetics, and control experiments, we show that ammonia and CO 2 are crucial for achieving optimal glycolysis via transesterification. Our method offered a traceless, environmentally friendly, and practical approach for polyester recycling and cotton recovery, representing a significant step toward sustainable, closed-loop production of plastics and textiles.