Sustainable Valorization of E‑Waste Plastic through Catalytic Pyrolysis Using CO₂

A massive amount of waste of electrical and electronic equipment (E-waste) is being discarded as a solid waste. A valorization platform for the organic part in E-waste has not been fully matured, while metallic compounds have been properly recycled. In these respects, a reliable disposal platform for complex plastic compounds in E-waste is developed in this study. Using a pyrolysis platform, the complicated plastic mixture in E-waste was valorized into value-added products. To deliberate a more environmentally benign process, CO₂ was used as a cofeedstock. As a model E-waste, LCD monitor waste (LMW) was tested. The exact types of plastics in LMW (polyacrylonitrile, polybutadiene, polystyrene, poly­(methyl methacrylate), polyethylene terephthalate, and polycarbonate) and their mass fractions were determined. From pyrolysis of LMW, the heterogeneous mixture of liquid (toxic) hydrocarbons was generated. To selectively convert/detoxify hydrocarbon into syngas (H₂/CO), catalytic pyrolysis was applied. A Ni catalyst led to chemical bond scissions, improving H₂ formation. When CO₂ was fed as a cofeedstock, volatile hydrocarbons were further turned into CO through chemical reactions between CO₂ and hydrocarbons. This synergistic effect of CO₂ and Ni catalyst improved syngas formation more than 15 times. CO₂ also greatly extended the stability of a catalyst, effectively preventing coke formation.