Recyclable MFe2O4(M = Mn, Zn, Cu, Ni, Co) coupled micro-nano bubbles for simultaneous catalytic oxidation to remove NO: Xand SO2in flue gas

Abstract

NOx can be efficiently removed by micro-nano bubbles coupling with Fe3+ and Mn2+, but the catalyst cannot be reused and the adsorption wastewater should be treated. This work developed a new technology that uses micro-nano bubbles and recyclable MFe2O4 to simultaneously remove NOx and SO2 from flue gas, and clarified the effectiveness and reaction mechanism. MFe2O4 (M = Mn, Zn, Cu, Ni and Co) prepared by a hydrothermal method was characterized. The results show that MFe2O4 can be activated to produce OH which can accelerate the oxidation absorption of NOx. Compared with no catalyst, the NOx conversion rate increased from 32.85% to 83.88% in the NOx-SO2-MFe2O4-micro-nano bubble system, while the removal rate of SO2 can reach 100% at room temperature. The catalytic activities of MFe2O4 showed the following trend: CuFe2O4 > ZnFe2O4 > MnFe2O4 > CoFe2O4 > NiFe2O4. The results provide a new idea for the application of advanced oxidation processes in flue gas treatment. This journal is