The role of plastic chemical recycling processes in a circular economy context

It is estimated that nearly 400 million tons of plastic are produced each year worldwide. However, only 10% of this enormous amount is recycled after use. Currently, mechanical recycling is the dominant method, despite certain operational limitations. To increase recycling rates, chemical recycling processes are emerging as viable alternatives, promising the creation of more valuable products. This comprehensive review begins with an introduction to ongoing plastic recycling technologies, covering general pretreatment methods for plastic waste and the taxonomy of various recycling technologies and their applications for specific polymer recycling. Then various aspects of chemical recycling are examined to explore its role within the context of a circular economy. Detailing chemical recycling technologies, such as depolymerization pathways and thermochemical pathways, are systematically elaborated. It also delves into optimization strategies, technological maturity, and economic assessments of chemical recycling. In addition, this review also examines the symbiotic and/or substitutional relationship between conventional recycling methods and alternatives, including biological recycling, biodegradable polymers, and eco-design. Finally, the approaches to improve the large-scale application of chemical recycling technology from the perspectives of technological level, infrastructure construction, public awareness enhancement, and national and international policy formulation are discussed. This review aims to provide theoretical support and practical recommendations for the future development of chemical recycling technologies to achieve the goals of sustainable development and a circular economy.