Simultaneous Removal of NO and SO 2 via an Integrated System of Nonthermal Plasma Combined with Catalytic Oxidation and Wet Electrostatic Precipitator

An integrated system of dielectric barrier discharge (DBD) combined with MnCu/Ti catalyst and wet electrostatic precipitator (DBD–catalyst–WESP) was constructed for simultaneous removal of SO 2 and NO. The removal mechanism and the effects of special energy density (SED) and initial concentrations of NO and SO 2 on oxidation efficiency were investigated. Experimental results showed that compared with Mn/Ti and Cu/Ti, the MnCu/Ti catalyst exhibited a higher dispersion of active constituents and has more catalytic oxidation active substances. The removal efficiencies of NO and SO 2 in the DBD-catalyst system increased with increasing SED (15–275 J/L), and the lower the initial concentration was, the higher were the simultaneous removal efficiencies of NO and SO 2 . The competitive relationship between the removal of NO and SO 2 was clarified. Compared with the DBD–catalyst system, the DBD–catalyst–WESP system significantly improved the simultaneous removal efficiencies of NO and SO 2 . With low initial concentrations (200 mg/m 3 NO and 1000 mg/m 3 SO 2 ), the simultaneous removal efficiencies in DBD–catalyst–WESP reached the highest values (93.4% for NO and 100% for SO 2 ) at SED = 275 J/L. According to ion chromatography measurements, the DBD–catalyst oxidation products were NO 2 and SO 3 . Most of the oxidation products were captured and converted into nitrate ions and sulfate ions in WESP.