(154w) A Sustainable Hybrid Catalyst to Depolymerize Recycled Polyethylene Terephthalate

Chemical recycling technologies use methods to break down ever-growing plastic waste into valuable materials (e.g., petrochemical feedstock, monomers and building blocks for new plastics, and fuels). Here we propose a green hybrid catalyst for the depolymerization of polyester plastics waste. A catalyst composed of carbon nanodots doped with zinc (Zn-CNDs) on a functional zeolite framework (Zn-CNDs@zeolite) was successfully synthesized. CNDs were synthesized through a one-pot solvothermal method employing pyrolysis of plastic waste. The resulting CNDs were characterized by means of X-ray diffraction, microscopy, UV-Vis, and Raman spectroscopy techniques. The catalytic activity of the Zn-CNDs@zeolite for the depolymerization of recycled polyethylene terephthalate (rPET) was evaluated via glycolysis in a high-pressure reactor. PET waste from drinking water bottles, ethylene glycol (EG), and the Zn-CNDs@zeolite were feed to a high-pressure reactor and glycolysis of PET was performed at 200°C for 1h at pressures around 2 bar. Our results show that the Zn-CNDs@zeolite can efficiently depolymerize PET to its monomeric unit, bis(2-hydroxyethyl terephthalate (BHET) (or oligomers) by controlling the catalyst loading.