Electrochemically Mediated Alkaline Hydrolysis and Methanolysis of Poly(ethylene terephthalate) (PET)

Abstract

Low-impact, closed-loop recycling of plastics is crucial to sustainably managing these ubiquitous and resource-intense materials. Our approach aimed to improve chemical recycling by integrating it with electrochemical processes to generate reactants electrochemically and depolymerize plastic in situ, with the objective of reducing both costs and environmental impacts. We investigated electrochemically mediated alkaline hydrolysis and methanolysis of poly(ethylene terephthalate) (PET) to achieve the following advantages over conventional methods: access to more extreme reactivity from applying an electrochemical driving force, application of more moderate operating conditions, and process intensification. Total PET conversion and product yields were measured to systematically investigate the performance effects of the catholyte methanol content, anolyte buffering, and temperature. Leveraging these insights to improve experimental conditions, we achieved 45 mol % PET conversion in 5 h at ambient pressure and relatively moderate temperature (50 °C) in 0.1 M NaClO₄ (100 mol % methanol) catholyte and 0.1 M Na₃PO₄ anolyte.