Recyclability and recovery of carbon from waste printed circuit boards within a circular economy perspective: A review

Waste printed circuit boards (WPCBs) are a significant component of electronic waste (e-waste) and are among the fastest-generating waste flows. The potentially negative impacts caused by e-waste on the environment and human health pose an increasingly apparent threat to people's everyday lives and well-being. The nonmetallic fraction (predominantly carbon) of WPCBs is characterized by heavy weight, low resource value, and complex composition, and these characteristics significantly restrict the recycling of the WPCBs to achieve a circular economy. To bring more attention and better guidance to carbon recycling in printed circuit boards, this study utilizes a recyclability model to analyze the potential carbon recycling in WPCBs. It also utilizes existing life cycle assessment results to evaluate the carbon emissions of WPCBs in waste management systems and to identify potential opportunities for carbon recovery within the entire system. In addition, this study reviews the latest technological advances in recovering carbon from WPCBs, including separation, oxidation, and activation. The properties of recycled carbon, such as porosity, adsorption, and electrochemical characteristics, are also a key focus of this review. The application of recycled carbon plays a crucial role in shaping the future direction of e-waste carbon recycling and its potential contribution to achieving a circular economy. The research results are expected to guide future carbon recycling processes and provide a reference for industrial development.