Simultaneous removal of NO and SO2 from flue gas using vaporized H2O2 catalyzed by nanoscale zero-valent iron

Abstract

To remove NO and SO from flue gas simultaneously, a heterogeneous catalytic oxidation system was developed with the nanoscale zero-valent iron (nZVI), vaporized HO, and sodium humate (HA-Na) acting as the catalyst, oxidant, and absorbent, respectively. The experimental results indicated that the desulfurization was mainly influenced by the absorption, and the denitrification was significantly affected by the catalytic oxidation parameters. Under the optimal conditions, the simultaneous removal efficiencies of SO and NO were 100 and 88.4%, respectively. The presence of OH during the removal process was proved by the scavenger tests, and the production ofOH with and without nZVI was indirectly evaluated by the electron paramagnetic resonance (EPR) and methylene blue experiments. Moreover, the fresh and aged nZVI were characterized by a series of techniques and the results suggested that the redox pair Fe/Fe released by nZVI could react with HO to provide the sustainable OH, which was important for the oxidation from NO and SO to NO and SO. The removal mechanism was proposed preliminarily based on the correlative experiments, characterizations, and references.

Removal of Gaseous Hydrogen Sulfide by a Photo-Fenton Wet Oxidation Scrubbing System

“…Relevant research ,, showed that a rise of the temperature would reduce the solubility of hydrogen sulfide in the reaction solutions, which was not conducive to the hydrogen sulfide removal. Furthermore, some results indicated that chemical reactions could be enhanced by elevating the temperature, − which would strengthen the hydrogen sulfide removal. However, for the photo-Fenton reaction process, free radical oxidation plays a dominant role for the hydrogen sulfide removal.…”

Catalytic Decomposition of H2O2 for NO Oxidation‐Removal over Hierarchical Fe‐ZSM‐5: Effect of Ethanol on Zeolite Performance

“…[8] Thus, the Fenton-like reaction with * OH radicals from H 2 O 2 decomposition over heterogeneous catalysts would be effective and feasible for NO-oxidation. [9] Hematite, [10] hematite doped alumina, [11] zero-valent iron, [12] ferric sulfate, [7] Y-Fe 2 O 3 @Fe 3 O 4 , [13] Fe 2.5 M 0.5 O 4 [14] and Fe 2 (MoO 4 ) 3 [15] have been developed for denitrification by catalytic H 2 O 2 -producing * OH radicals, and the high NO-removal conversions were observed. However, for those catalysts, the relative low surface area might impose low utilization of active sites.…”