Research on NO and SO removal using TiO-supported iron catalyst with vaporized HO in a catalytic oxidation combined with absorption process.

Simultaneous removal of NOx and SO is carried out by an oxidation-absorption process, which NO oxidized by active hydroxyl radicals (·OH) derived from catalytic decomposition of vaporized HO over FeO/TiO and then adsorbed by NaOH solution along with SO. FeO/TiO synthesized by wet impregnation method with an additional reduction under H atmosphere was characterized by XRD, FTIR, BET, XPS, and VSM analysis. Effects of HO concentration, HO injection rate, reaction temperature, gas flow rate, and flue gas component on simultaneous removal were investigated. The experimental results show that NO can be effectively oxidized by highly reactive ·OH radicals generated from HO decomposition over FeO/TiO catalyst, and removal efficiencies of 93.31% for NO, 85.90% for NOx, and 100% for SO were obtained. The surface zero-valent iron (Fe) and divalent iron (Fe) are the key factors of the catalytic oxidation with hydroxyl radical. HO adsorption and dissociation mechanism on catalyst surface was studied using DFT calculation. The calculation results demonstrate that HO prefers to dissociate on iron containing surface, and ·OH radicals generation follow by Haber-Weiss (H-W) mechanism. The stable oxidative product of HNO and HNO were generated through NO/NO and HO co-adsorption on the FeO/TiO (0 0 1) surface.