Title: Metal-organic frameworks as a crystallization tool for facilitating plastic recycling solutions

Abstract: Polyethylene terephthalate (PET) plastic, widely recognized in the form of single-use water bottles, is one of the most ubiquitous polymers. In fact, it is even more extensively use for making textile fibers, where it is called polyester. Bottles, which are pure PET, are typically mechanically recycled, where they are melted down and made into something new. However, the presence of additional components like dyes and coatings in polyester fabrics complicate its mechanical recycling suitability. Chemical recycling, which breaks PET down into its original building blocks, offers a promising alternative. Yet, the non-PET elements lead to generation of impurities in the final product, making it difficult to extract pure monomer (BDC, or benzene-1,4-dicarboxylic acid) from textiles. In this study, we introduce a solution using reactive crystallization to convert PET into a metal-organic framework (MOF), effectively separating BDC from impurities. Demonstrated on PET fabric, this method removes trapped impurities, resulting in colorless BDC akin to virgin-grade monomer. These findings signify a breakthrough in plastic recycling, offering a new avenue for selectively recovering valuable materials from complex mixtures.