Ultraviolet-induced nitric oxide removal using H2O/O2 catalyzed by Fe/TiO2: Feasibility and prospect

A novel photo-catalytic oxidation method using ultraviolet (UV) and iron-loaded titanium dioxide (Fe/TiO2) catalyst was developed to remove NO from the flue gas, by which the removal efficiency of 53.4% was achieved without extra oxidant, and the efficiencies were 79.5% and 93.6% when 2 wt% and 4 wt% H2O2 were used, respectively. Increasing temperature and O2 concentration could facilitate the NO removal; neutral/alkaline solution and UV wavelength of 185 nm were more effective in removing NO, while the excess SO2 and gas flow rate were not conducive to remove NO. Besides, the NO removal mechanism was preliminarily speculated, in which •OH and O3 were determined to be the main oxidizing species in the photolysis and photo-catalysis of H2O/O2, the radicals were also formed in the catalysis of photo-generated H2O2 by Fe/TiO2, and the main removal product was identified as NO3− by ion chromatography (IC). Meanwhile, the stability and reuse of catalyst were investigated by the recycling test.