Chemical Recycling of Polyethylene Terephthalate: A Review

Polyethylene terephthalate (PET) is one of the most widely produced synthetic polymers, extensively used in beverage bottles, food packaging, and textile fibers due to its excellent mechanical strength, transparency, and chemical resistance. However, the massive consumption of PET has generated an escalating global plastic waste crisis. Mechanical recycling remains the dominant strategy for PET waste management, yet it suffers from polymer degradation, contamination sensitivity, and limited recyclability. Chemical recycling has therefore emerged as a promising approach to close the carbon loop by converting PET waste into its constituent monomers or other high-value chemicals. In recent years, significant progress has been achieved in catalytic depolymerization strategies including glycolysis, methanolysis, hydrolysis, aminolysis, and hydrogenolysis. In addition, emerging approaches such as enzymatic depolymerization, solvent-assisted recycling, and tandem catalytic upgrading have further expanded the valorization potential of PET waste. This review provides a comprehensive overview of recent advances in PET chemical recycling, focusing on reaction mechanisms, catalytic systems, process intensification strategies, and product upgrading pathways. Special emphasis is placed on heterogeneous catalysis, green solvents, and integrated catalytic systems for converting PET into monomers such as terephthalic acid and ethylene glycol or into value-added chemicals including fuels, polymers, and aromatic compounds. Finally, current challenges and future research directions are discussed, highlighting opportunities for designing sustainable catalytic systems and scalable industrial processes for circular plastic economy.