Catalytic fast pyrolysis over heavy metals-containing livestock manure biochar catalyst for polystyrene upcycling

Abstract

The perpetual market demand for polystyrene results in the gradual accumulation of polystyrene waste, placing a serious burden on the environment. This study proposed a promising method to upcycle polystyrene for styrene-derived monomers through catalytic fast pyrolysis. The metals-incorporated biochar catalysts were synthesized from heavy metals-contaminated manure waste for catalytic fast pyrolysis of polystyrene. The experimental results showed that the bimetallic biochar-derived catalyst containing Zn and Cr (Zn-Cr/C) was more conducive to the liquid production, with an extremely high yield of 88.22 wt%. Monometallic Pb-incorporated biochar catalyst (Pb/C) and bimetallic Zn-Cu co-doped on biochar (Zn-Cu/C) were more favorable for the production of pure styrene, with the mass yield of 61.26 wt% and 60.39 wt%, respectively. Additionally, the study elucidated a deep understanding of the reaction mechanisms involved in the catalytic fast pyrolysis of polystyrene. Simply put, this study introduced a new concept to convert heavy metal-contaminated animal manure into metal-incorporated biochar catalysts for catalytic conversion of polystyrene waste in pure styrene-based monomers.