Regenerable Cobalt Oxide Loaded Magnetosphere Catalyst from Fly Ash for Mercury Removal in Coal Combustion Flue Gas

To remove Hg-0 in coal combustion flue gas and eliminate secondary mercury pollution of the spent catalyst, a new regenerable magnetic catalyst based on cobalt oxide loaded magnetospheres from fly ash (Co-MF) was developed. The catalyst, with an optimal loading of 5.8% cobalt species, attained approximately 95% Hg-0 removal efficiency at 150 degrees C under simulated flue gas atmosphere. O-2 could enhance the Hg-0 removal activity of magnetospheres catalyst via the Mars-Maessen mechanism. SO2 displayed an inhibitive effect on Hg-0 removal capacity. NO with lower concentration could promote the Hg-0 removal efficiency. However, when increasing the NO concentration to 300 ppm, a slightly inhibitive effect of NO was observed. In the presence of 10 ppm of HCl, greater than 95.5% Hg-0 removal efficiency was attained, which was attributed to the formation of active chlorine species on the surface. H2O presented a seriously inhibitive effect on Hg-0 removal efficiency. Repeated oxidation-regeneration cycles demonstrated that the spent Co-MF catalyst could be regenerated effectively via thermally treated at 400 degrees C for 2 h.