Closed-Loop Recycling: Upcycling PET into MOFs for Catalytic Hydrogenolysis and High-Purity Monomer Recovery

Abstract

Plastic waste has become a critical global concern, necessitating the urgent development of technologies for high-value utilization and chemical recycling. This work introduces a sustainable and innovative approach to addressing the global challenge of plastic waste by upcycling waste polyethylene terephthalate (PET) into high-value metal-organic frameworks (MOFs) and employing them in PET chemical recycling. A one-pot synthesis of hcp UiO-66 MOFs was achieved using formic acid (FA) as a depolymerization catalyst, solvent, and crystallization agent, with FA recyclability enhancing the economic and environmental practicality of the process. The synthesized MOFs were then utilized as efficient catalysts for the hydrogenolysis of PET, regenerating high-purity terephthalic acid (BDC) monomers in a solvent-free process. The sublimation of BDC enabled direct product recovery, eliminating the need for complex separation steps and facilitating continuous recycling through PET replenishment. This study demonstrates a "waste-to-resource" pathway that not only addresses PET waste management but also creates functional materials with high-value applications, aligning with global sustainability goals and advancing circular economy frameworks.