Co-Upcycling of Waste Electronic Plastics and Algae Biomass into High-Quality Pyrolysis Oil through Self-Catalytic Debromination and Oil Upgrading

Abstract

Upcycling waste plastics into fuel oil and gases offers an important route for waste-to-wealth conversion. However, the valorization of waste electronic plastics (WEP) remains challenging because the brominated flame retardant (BFR) components are easily converted to hazardous brominated organics, which lowers the product quality. Here, we report the copyrolysis of WEP with iron-rich algae biomass waste for high-quality oil production without the need for the external addition of a catalyst for bromine (Br) fixation. Iron-based flocculants are commonly used for collecting algae biomass from an algal-bloomed lake, resulting in iron-rich algae biomass. During its pyrolysis, the iron component was converted into Fe₂O₃, which served as an efficient endogenous catalyst to facilitate Br fixation and WEP depolymerization. The oil product of the copyrolysis system (WEP/AB = 1:1, 600 °C) exhibited 80% less Br content, a 30% higher fraction of total aromatic compounds, and a 15% higher oil yield than those of the WEP-alone group. Overall, our work offers a facile self-catalytic debromination strategy for WEP upcycling by simply mixing it with iron-rich algae biomass waste for copyrolysis. Such a “two-birds-one-stone” strategy may also be extended to the upcycling of other halogen-containing organic wastes.