Scale-up synthesis of bioplastics polyglycolic acid from waste plastic polyethylene terephthalate

Abstract

The conversion of discarded polyethylene terephthalate (PET) into bioplastics polyglycolic acid (PGA) represents a pivotal step in promoting the reuse of PET and bolstering the adoption of PGA. However, this promising pathway is currently hindered by (i) low conversion rate of PET-derived ethylene glycol (EG) into glycolate and (ii) high cost associated with purifying glycolic acid (GA). Herein, we designed a novel Pd-CoCr2O4/NF catalyst for continuous electrosynthesis of glycolate, achieving a 75% conversion rate of EG at a current density of ~280 mA cm–2. Furthermore, we devised a cost-effective purification process that circumvents unnecessary acidification steps. A scale-up experiment involving 20 kg of waste PET was conducted and resulted in an 87% PGA yield. Techno-economic analysis confirmed the cost competitiveness of PGA produced through this environmental-friendly method. This study shows a sustainable route to mitigate the environmental impact of waste plastics and reduce the production costs of bioplastics.