The removal of NO from flue gas by NaOH-catalyzed H2O2 system: Mechanism exploration and primary experiment

Abstract

Currently, most advanced oxidation denitrification technologies require long flue gas residence time to obtain ideal NO removal efficiency. The NaOH-catalyzed H2O2 system proposed in this paper can obtain 98% NO removal efficiency under the condition of flue gas residence time of 3 s. The mechanism of NO removal and H2O2 decomposition to O2 were proposed. It was confirmed with ESR (Electron-spin-resonance), inhibitor experiments and UV-Vis spectrophotometer that the main group in the reaction process was·O2- radicals, which reacted with NO to form ONOO-, and ONOO- would be gradually transformed into NO3- and NO2- in the air. The effect of some primary factors on the NO removal efficiency and the percentage of H2O2 decomposition to O2 were also investigated. The increase of initial pH has a positive effect on NO removal, while the promotion of NO removal by increasing H2O2 concentration and reaction temperature is limited and the increase of NO has a negative effect on NO removal. Initial pH has a dual impact on the percentage of H2O2 decomposition to O2, H2O2 concentration and reaction temperature promote the decomposition of H2O2 to O2, while NO concentration has an inhibiting effect on it.