Construction of heterogeneous Fe-Ce@SiC/H2O2 system and its NO removal

Conventional SCR denitrification technology often encounters difficulties in adapting to the flue gas scenarios characterized by low temperatures and high moisture. Therefore developing a low-temperature denitrification process that is both cost-effective and efficient is crucial. In this paper, a heterogeneous Fe-Ce@SiC/H₂O₂ oxidation-absorption system was constructed. The NO removal performances of this system were systematically investigated. The results show that, compared with the acidic conditions, the heterogeneous Fe-Ce@SiC/H₂O₂ system under the alkaline conditions exhibited better NO removal performance. Specifically, under optimal experimental conditions, the removal efficiency of NO in the Fe-Ce@SiC/H₂O₂ system could reach up to 87.1 %. When the circulating water flow rate was further increased to 600 ml/min, NO could be completely removed. Combined with the results of SEM, XRD, BET, XPS, EPR, the gas-liquid phase products analysis, and the radical quenching experiments, the electrochemical test, the possible reaction mechanism was proposed. The electron transfer and co-catalysis between Fe and Ce facilitated the regeneration of the metal active sites, therefore, H₂O₂ was enhanced to produce more •O₂^- radicals under the catalysis of Fe-Ce@SiC. These •O₂^- radicals are the principal active species for NO oxidation under the alkaline conditions, whereas •OH radicals and ¹O₂ are relatively less active. The purified NO is mainly converted into NO₃^- and a small amount of NO₂^- in the absorption solution. The research results not only further improve the theoretical system of NOx removal by the heterogeneous Fenton system, but also expand the applicability of this technology in the field of flue gas denitrification.