Reactive Depolymerization\nof Polyethylene Terephthalate\nTextiles into Metal–Organic Framework Intermediates Produces\nAdditive-Free Monomers

Polyethylene terephthalate (PET)\nfibers can be transformed\ninto\na plethora of textile products by adding dyes, coatings, and trims.\nHowever, these additives make the chemical recycling of textile fibers\nchallenging. The extraction of high-purity benzene-1,4-dicarboxylic\nacid (BDC), the major PET monomer from textiles, is, therefore, a\nmajor technical hurdle in textile circularity. Here, we demonstrate\nthe extraction of high-quality BDC from PET fibers in textiles. Our\napproach uses reactive crystallization to turn PET directly into a\nmetal–organic framework (MOF) using only metal salts and water\nas chemical inputs. Our process is base-free and organic-solvent-free.\nAs BDC is the only component in this mixture capable of forming an\nextended, crystalline MOF network, the BDC monomers are separated\nfrom impurities as the MOF crystallizes. We demonstrate this concept\non a post-consumer PET fabric, extracting colorless BDC monomers spectroscopically\nreminiscent of a virgin-grade material as the final product. Systematic\ncontrol of the reaction parameters reveals the MOF assembly mechanism\nand the importance of the reaction conditions in promoting the metal-BDC\ncomplexation step prior to the MOF assembly.