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

Currently, most advanced oxidation denitrification technologies require long flue gas residence time to obtain ideal NO removal efficiency. The NaOH-catalyzed H 2 O 2 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 H 2 O 2 decomposition to O 2 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·O 2 - radicals, which reacted with NO to form ONOO - , and ONOO - would be gradually transformed into NO 3 - and NO 2 - in the air. The effect of some primary factors on the NO removal efficiency and the percentage of H 2 O 2 decomposition to O 2 were also investigated. The increase of initial pH has a positive effect on NO removal, while the promotion of NO removal by increasing H 2 O 2 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 H 2 O 2 decomposition to O 2 , H 2 O 2 concentration and reaction temperature promote the decomposition of H 2 O 2 to O 2 , while NO concentration has an inhibiting effect on it.