(2026) Chemical Engineering Journal_Co-catalyzed boudouard reaction-derived biochar for enhanced persulfate activation

Lee Y.-J.; Kim Y.; Lee D.; Kwon E.E.

(Elsevier B.V.) Chemical Engineering Journal ISSN: 13858947 Vol.538 Issue. Article No.176663 DOI: 10.1016/j.cej.2026.176663

Carbon etching of biochar via the Boudouard reaction offers a promising thermochemical strategy for tailoring pore structure and surface functionalities. However, the practical application of CO₂-assisted biochar modification is often constrained by the high activation energy and slow kinetics of the Boudouard reaction. In this study, cobalt (Co) was introduced as a catalytic promoter to accelerate the Boudouard reaction during CO₂-assisted pyrolysis of wheat straw (WS). Thermogravimetric analysis revealed that Co impregnation decreased the onset temperature of the Boudouard reaction from 740 to 460 °C, indicating enhanced reaction kinetics. The resulting Co-loaded biochar synthesized under CO₂ atmosphere CoWSB (CO₂) exhibited a well-developed mesoporous structure, increased abundance of electron-rich C-O surface functionalities, and highly dispersed Co active sites. Catalytic performance evaluation demonstrated that CoWSB (CO₂) achieved complete removal of bisphenol A through activation of peroxydisulfate and peroxymonosulfate, outperforming the counterpart biochar prepared under an inert N₂ atmosphere. In addition to improved catalytic activity, Co impregnation promoted syngas production during WS pyrolysis, yielding 138.9 mmol of CO and 10.7 mmol of H₂. This enhancement is attributed to Co-catalyzed reforming and conversion of volatile oxygenated intermediates, which facilitates CO formation via the Boudouard reaction and secondary cracking reactions. © 2026 Elsevier B.V.

This work was supported by the National Research Foundation of Korea (NRF) grants funded by the Korean Government (MSIT) (Grant No. RS-2023-NR077231).