Preparation of magnetic Co-Fe modified porous carbon from agricultural wastes by microwave and steam activation for mercury removal

In this article, a magnetic cobalt-iron modified porous carbon derived from agricultural wastes by microwave and steam activation was developed to remove elemental mercury in coal-fired flue gas. The effects of operating parameters on Hg capture were discussed. Reaction mechanism and regeneration performance were also studied. Results show that the activation of microwave and steam significantly improves the pore structure of the porous carbon. The ultrasound-assisted impregnation promotes the dispersion of cobalt oxides and iron oxides on the samples. The Co0.4Fe12/RSVVU(500) sorbent exhibits highest Hg removal efficiency at 130 C. The characterization analysis shows that cobalt oxides and iron oxides are the main active components for Hg removal. The XPS analysis suggests that the chemisorption oxygen and the lattice oxygen (derived from Co3+/Co2+ and Fe3+/Fe2+) participate in the Hg capture process. Moreover, the cobalt-iron mixed oxide modified porous carbon has a good regeneration performance, which is conductive to reduce the costs in the future application.