SO2 and NO removal from flue gas over V2O5/AC at lower temperatures — role of V2O5 on SO2 removal

Supporting V2O5 onto an activated coke (AC) has been reported to significantly increase the AC's activity in simultaneous SO2 and NO removal from flue gas. To understand the role of V2O5 on SO2 removal, V2O5/AC is studied through SO2 removal reaction, surface analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) techniques. It is found that the main role of V2O5 in SO2 removal over V2O5/AC is to catalyze SO2 oxidation through a VOSO4-like intermediate species, which reacts with O2 to form SO3 and V2O5. The SO3 formed transfers from the V sites to AC sites and then reacts with H2O to form H2SO4. At low V2O5 loadings, a V atom is able to catalyze as many as 8 SO2 molecules to SO3. At high V2O5 loadings, however, the number of SO2 molecules catalyzed by a V atom is much less, due possibly to excessive amounts of V2O5 sites in comparison to the pores available for SO3 and H2SO4 storage.