Advances and Challenges for Catalytic Recycling and Upgrading of Real-World Mixed Plastic Waste

Abstract

Catalytic conversion of waste plastic has attracted widespread attention due to pressing environmental issues and energy crisis. Although some methods have been successful in converting single-component plastic waste, unfortunately, plastic waste in the real-world typically made up of a mixture of various plastics, which poses significant difficulties and challenges for catalyst selection and product distribution in the catalytic conversion of mixed plastic. Recently, a number of new technologies have been developed to address the catalytic conversion of mixed plastic, aiming to overcome the limitations of current methods and drive progress in this field. This review summarizes the progress in catalytic recycling and upgrading of mixed plastic into monomers or value-added chemicals by thermocatalysis, photocatalysis/photothermal catalysis, and tandem chemical-biocatalysis. The construction of efficient catalysts, understanding of reaction pathways, design of reaction systems, and practical applicability in each method are highlighted and discussed in detail. Our goal is to elucidate the catalytic mechanisms and principles of process design, providing guidance for the development, integration or optimization of new technologies that enhance catalytic efficiency and processing capabilities for mixed plastic waste. Furthermore, the economic feasibility and environmental impact of mixed plastic treatment were comprehensively evaluated by summarizing techno-economic analysis and life cycle assessment studies. Lastly, the remaining technological challenges and future directions for the industrial-scale conversion of real-world mixed plastic waste to generate value-added products are described.