Recyclable MFe2O4 (M = Mn, Zn, Cu, Ni, Co) coupled micro–nano bubbles for simultaneous catalytic oxidation to remove NOx and SO2 in flue gas

摘要

NO _( x ) can be efficiently removed by micro–nano bubbles coupling with Fe ~(3+) and Mn ~(2+) , 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 MFe _(2) O _(4) to simultaneously remove NO _( x ) and SO _(2) from flue gas, and clarified the effectiveness and reaction mechanism. MFe _(2) O _(4) (M = Mn, Zn, Cu, Ni and Co) prepared by a hydrothermal method was characterized. The results show that MFe _(2) O _(4) can be activated to produce ˙OH which can accelerate the oxidation absorption of NO _( x ) . Compared with no catalyst, the NO _( x ) conversion rate increased from 32.85% to 83.88% in the NO _( x ) –SO _(2) –MFe _(2) O _(4) -micro–nano bubble system, while the removal rate of SO _(2) can reach 100% at room temperature. The catalytic activities of MFe _(2) O _(4) showed the following trend: CuFe _(2) O _(4) > ZnFe _(2) O _(4) > MnFe _(2) O _(4) > CoFe _(2) O _(4) > NiFe _(2) O _(4) . The results provide a new idea for the application of advanced oxidation processes in flue gas treatment.