Aqueous Upcycling of Polyethylene Furanoate From Mixed Plastic Feeds Into Metal-Organic Frameworks

Mixed and contaminated plastic waste is the dominant obstacle to plastics' circularity because most recycling or upcycling technologies require clean, pre-sorted feedstocks. Here, we demonstrate a sorting-free upcycling method with purification embedded in upcycling. Polyethylene furanoate (PEF), an emerging biomass-derived polyester, is converted in water into the valuable metal-organic framework (MOF) MIL-160 in high yield. This method remains effective when using unsorted polymer mixtures, including mixtures containing competing polyesters such as polyethylene terephthalate (PET) and polylactic acid (PLA), yielding a pure MOF with no loss in sorption performance. To address the MOF's own end-of-life, we demonstrate the ease of recovering 2,5-furan-dicarboxylic acid (FDCA) from MIL-160 for recycling and redeployment to produce other MOFs such as CAU-28. This connects plastic upcycling to MOF end-of-life management, showing that the upcycled product is not a dead-end material but a reversible reservoir of FDCA that can be recovered and recirculated. Life cycle assessment showed that producing MIL-160 from mixed PET/PEF plastic feedstock results in a 31% reduction in life-cycle global warming potential compared to using biomass directly. Additionally, techno-economic analysis supported the economic feasibility of producing MIL-160 from mixed PET/PEF. Valorizing PEF into MOFs with diverse applications offers viable end-of-life solutions for these bioplastics.