High value-added conversion and functional recycling of waste polyethylene terephthalate (PET) plastics: A comprehensive review

Abstract

In conjunction with the extensive production and widespread utilization of polyethylene terephthalate (PET) plastics, the issue of environmental pollution resulting from PET product disposal has gained increasing prominence. Consequently, researchers have been focusing on the development of cost-effective, sustainable, environmentally friendly, and efficient methodologies for recycling waste PET plastics and converting them into value-added products. PET, being a polymer with a high carbon content, serves as an exemplary carbon source for various carbon materials, encompassing porous carbon materials and carbon dots. Hence, it is imperative to design and develop carbon materials with solid functionality and wide-ranging applications utilizing waste PET. Additionally, PET can be depolymerized to produce terephthalic acid (TPA), which finds extensive application as an organic ligand for synthesizing metal-organic frameworks materials (MOFs). Consequently, low-cost waste PET is regarded as an optimal precursor for the large-scale preparation of MOFs. Converting waste PET into MOFs presents a novel strategy for chemical recycling. This review presents the recent advancements in functional upcycling and high value-added conversion of waste PET plastics, such as carbon materials, MOFs, aerogel and hydrogel. It comprehensively outlines the preparation methods for diverse categories of porous carbon materials and MOFs, emphasizing their applications in adsorption, energy storage, and catalysis, while also proposing future research directions pertaining to waste PET plastics.