Effect of CO2/O2 on Catalytic Reduction of NO by Iron

This paper presents the results of the reaction between metallic iron mesh rolls and NO in the presence of CO2/O-2 at different temperatures. All experiments were carried out in a ceramic tube controlled by the temperature programmed electrical furnace. About 99% NO reduction was achieved when temperature was above 700 degrees C in the absence of CO2/O-2. Results showed that CO2 in the flue gas had little effect on the NO reduction. NO reduction efficiencies were observed to exceed 95% for all CO2 concentrations at above 700 degrees C. The addition of O-2, however, caused a sudden drop by about 76% in NO reduction efficiency. Scanning electron microscope (SEM) results showed that the oxidation of iron in O-2 atmosphere led to a more continuous and impervious oxide layer than that in CO2 atmosphere. Results using X-ray diffraction (XRD) to detect the iron samples after reactions revealed that FeO, Fe3O4, Fe and Fe2O3 were formed in CO2 atmosphere, but Fe3O4 and Fe2O3 were formed when O-2 was added.