Microwave-assisted recycling of plastic waste into value-added chemicals: challenges, recent advances, and perspectives

Abstract

Global plastic production exceeded 413.8 million tons annually by 2023, yet recycling rates remain below 10%, with over 90% of plastics transitioning to waste post-consumption, exacerbating resource depletion and environmental contamination. Efficiently recycling such discarded plastics remains a critical challenge, necessitating robust, energy-efficient strategies to address this pressing global issue. Here, we review the state-of-the-art of the microwave-assisted recycling strategy, focusing on strategy design for converting diverse plastic types into value-added chemicals. Within microwave-assisted systems, dielectric materials serve as primary microwave absorbers, facilitating targeted, efficient heating that minimizes energy loss. For polyester/polyamide, reversible depolymerization occurs under relatively mild conditions, yielding monomers that may be directly reused for virgin plastic production. In contrast, recalcitrant polyolefins, characterized by high chemical inertness, can be converted to olefin or aromatic chemicals through recycling strategies. Additionally, plastic-containing waste can be recycled into valuable chemicals through co-recycling strategies. Key parameters, including the catalyst type, reaction temperature, reaction time, and feedstock composition, collectively govern product distribution and yield.