Recent developments in recycling of post-consumer polyethylene waste

With increasing emphasis on sustainable development goals, the recycling of end-of-life waste plastics has gained significant attention because of its role in protecting the environment and conserving resources. Polyethylene (PE) has been in use since the 1950s because of its excellent chemical resistance, low cost and processing convenience. It is widely used in packaging, agriculture, daily products and other fields, and its output has increased yearly. In this review, a comprehensive summary of the recent advances in PE recycling, including mechanical and chemical recycling, is presented. The section on mechanical recycling outlines traditional and emerging mechanical recycling methods, emphasizing their advantages and disadvantages. The section on chemical recycling is categorized into several subsections, including thermochemical depolymerization, metal-catalytic depolymerization, novel-catalytic degradation (such as biological catalysis, photocatalysis, and photo/electrocatalysis), macromolecular transformation, and carbonization. Simultaneously, we highlighted the advantages and disadvantages of these recycling processes based on their operational principles and environmental/economic benefits. Finally, some insights into future directions for recycling PE are offered, focusing on balancing the efficiency and environmental impact of processes through material innovation, mechanism research, system design, and interdisciplinary collaboration.