Simultaneous catalytic oxidation of nitric oxide and elemental mercury over Cu-Fe binary oxide treated by oxygen non-thermal plasma

In this study, non-thermal plasma (NTP) was adopted to improve the catalytic oxidation performance of Cu-Fe binary oxides (CFs) for efficient simultaneous removal of NO and Hg-0 from coal combustion flue gas. Sample characterization indicated that the pore structure, surface morphology, and crystalline phases of CF samples were not changed after plasma treatment whereas the contents of lattice oxygen (O-1), Fe3+, and Cu2+ were largely increased. The treated CF samples exhibited far better NO removal performance compared with raw CF over a wide reaction temperature range (150-450 degrees C). The influences of plasma discharge time, discharge power, discharge atmosphere, and reaction temperature on NO removal performance were analyzed. O-2 facilitated Hg-0 and NO removal center dot H2O had adverse effect on Hg-0 and NO removal. To some extent, the CF samples exhibited better resistant to sulfur poisoning due to the presence of Fe species. Moreover, the simultaneous removal behavior of Hg-0 and NO over the modified CF samples were analyzed. NO facilitated Hg-0 removal, but He had a slight inhibitory impact on NO removal. The optimum reaction temperature of simultaneous removal of NO and Hg-0 was 300 degrees C. Finally, the mechanism responsible for NO/Hg-0 removal was revealed, where CuO and Fe2O3 served as active components. During NO removal process, Fe3+, Cu2+ and O-1 were first consumed and then recovered due to the existence of O-2. Hg-0 catalytic oxidation dominated the He removal process because Hg-0 adsorption equilibrium was reached in a short time.

Automated summary

In this study, non-thermal plasma (NTP) was used to improve the catalytic oxidation performance of Cu-Fe binary oxides (CFs) for simultaneous removal of NO and Hg-0 from coal combustion flue gas. The treated CF samples showed significantly better NO removal performance compared to the raw CF samples over a wide range of reaction temperatures. The effects of plasma discharge time, power, atmosphere, and reaction temperature on NO removal were analyzed. The presence of O-2 facilitated Hg-0 and NO removal, while H2O had adverse effects. The CF samples displayed better resistance to sulfur poisoning and the optimum reaction temperature for simultaneous NO and Hg-0 removal was determined to be 300 degrees C. The mechanism responsible for NO/Hg-0 removal was revealed, with CuO and Fe2O3 as active components.