Reactive Depolymerization of Polyethylene Terephthalate Textiles into Metal–Organic Framework Intermediates Produces Additive-Free Monomers

Polyethylene terephthalate (PET) fibers can be transformed into a plethora of textile products by adding dyes, coatings, and trims. However, these additives make the chemical recycling of textile fibers challenging. The extraction of high-purity benzene-1,4-dicarboxylic acid (BDC), the major PET monomer from textiles, is, therefore, a major technical hurdle in textile circularity. Here, we demonstrate the extraction of high-quality BDC from PET fibers in textiles. Our approach uses reactive crystallization to turn PET directly into a metal–organic framework (MOF) using only metal salts and water as chemical inputs. Our process is base-free and organic-solvent-free. As BDC is the only component in this mixture capable of forming an extended, crystalline MOF network, the BDC monomers are separated from impurities as the MOF crystallizes. We demonstrate this concept on a post-consumer PET fabric, extracting colorless BDC monomers spectroscopically reminiscent of a virgin-grade material as the final product. Systematic control of the reaction parameters reveals the MOF assembly mechanism and the importance of the reaction conditions in promoting the metal-BDC complexation step prior to the MOF assembly.