A comprehensive review on pyrolysis of E-waste and its sustainability

Many facets of our civilization's contemporary life are related to the use of electrical and electronic equipment (EEE). EEE replacement is becoming more common as the need for high-performance EEE grows and technical advancement accelerates. As a result, a massive quantity of electronic waste (e-waste) is generated. One way of recycling e-waste is through pyrolysis, which is a thermochemical method used to recover polymers and concentrate metals into a solid residue. Additionally, this technique may be modified or integrated with other technologies to reduce the number of organic halides produced by harmful brominated flame retardants (BFRs), often used as additives in these materials. This article provides a comprehensive review in the context of pyrolysis of e-waste and its sustainability. The structure and components of the five significant types of e-waste, including printed circuit boards (PCBs), lithium-ion batteries (LIBs), tantalum capacitors (TCs), light-emitting diodes (LEDs), and liquid crystal displays (LCDs), are first discussed. Then five methods of e-waste pyrolysis, including vacuum pyrolysis, catalytic pyrolysis, co-pyrolysis, microwave pyrolysis, and plasma pyrolysis, have been carefully studied and the merits and demerits of each method are presented. In the following, the sustainability of the pyrolysis process is examined from three perspectives: economic, environmental, and social. In the end, ongoing challenges of e-waste pyrolysis and recommendations for future directions are also addressed. E-waste pyrolysis is still not completely industrialized. However, it can be said that it is a sustainable method, and the suitability of this method has been proven on the laboratory scale. It is hoped that we will see the industrialization of this method in industrialized and developing countries in the future.