A sustainable framework for advancing circular practices for polyethylene terephthalate textiles: optimized recycling of depolymerization byproducts and LCA validation

Abstract

This study demonstrates a novel circular approach for discarded polyethylene terephthalate (PET) textiles with life cycle assessment (LCA) validation, proposing an optimized recycling method for PET depolymerization byproducts. The experimental approach emphasizes sourcing the metal–organic framework ingredients including metal and linker components from a single PET depolymerization reaction. For depolymerization, a metal salt-based deep eutectic solvent (DES) composed of p-toluene sulfonic acid and iron(III) chloride hexahydrate was employed acting as both solvent and catalyst. Sequential recovery processes for multiple depolymerization products were established, and their recyclability was demonstrated. LCA was performed on the varied scenarios of the developed process, and the results provided solid grounds to conclude that the suggested process produces relatively less burden on the environment, attributed to the effective catalytic action of DES and the maximized use of byproducts generated from the depolymerization reactions. This work pioneers a comprehensive approach integrating novel experimental methods with LCA validation, establishing a robust proof-of-concept for maximizing the recycling potential of PET depolymerization products.