Effecting pattern study of SO2 on Hg0 removal over α-MnO2 in-situ supported magnetic composite

alpha-MnO2 was in-situ supported onto silica coated magnetite nanoparticles (MagS-Mn) to study the adsorption and oxidation of Hg0 as well as the effecting patterns of SO2 and O2 on Hg0 removal. MagS-Mn showed Hg0 removal capacity of 1122.6 mu g/g at 150 degrees C with the presence of SO2. Hg0 adsorption and oxidation efficiencies were 2.4% and 90.6%, respectively. Hg0 removal capability deteriorated at elevated temperatures. Surface oxygen and manganese chemistry analysis indicated that SO2 inhibited the Hg0 removal through consumption of adsorbed oxygen and reduction of high valence manganese. This inhibiting effect was observed to be counteracted by O2 at lower temperatures. O2 tended to compete with SO2 for active sites and further create additional adsorbed ox-ygen sites for Hg0 surface reaction via surface dissociative adsorption rather than replenish the active sites consumed by SO2. The high valence manganese was also preserved by O2 which was essential to Hg0 oxidation. The intervention of O2 in the inhibition of SO2 on Hg0 removal was weakened at temperatures higher than 250 degrees C. Aa a result, Hg0 tends to be catalytic oxidized in the condition of low reaction temperatures and with the presence of O2 over alpha-MnO2 oriented composites.

Automated summary

In this study, alpha-MnO2 was supported onto silica coated magnetite nanoparticles (MagS-Mn) to investigate the adsorption and oxidation of Hg0 and the influence of SO2 and O2 on Hg0 removal. MagS-Mn exhibited a Hg0 removal capacity of 1122.6 mu g/g at 150 degrees C with the presence of SO2. The adsorption and oxidation efficiencies of Hg0 were 2.4% and 90.6%, respectively. The Hg0 removal capability decreased at higher temperatures.