Preparation and low temperature denitrification properties of ferric oxide red supported manganese oxide and manganese cerium co-oxide catalyst

Abstract

Iron oxide red (IOR) is a kind of byproduct from spray pyrolysis treatment process of pickling waste liquid. In this project, manganese oxide and manganese cerium co-oxide were loaded onto the surface of IORto prepare IOR supported manganese oxide (Mnx/IOR) and IOR supported manganese-cerium co-oxide (Mnx-Cey/IOR) catalysts by a simple combustion method. Low temperature NH3-selective catalytic reduction (NH3-SCR) denitrification properties of the synthetic catalysts were studied. XRD, SEM, EDS, TEM, BET, XPS, H2-TPR and NH3-TPD were used to characterize the physiochemical properties of the catalysts. The results show that during the combustion process for preparing Mnx/IOR catalyst, MnOx, almost all in amorphous phase, can be well distributed on the surface of the IOR carrier. The NOx conversions of Mnx/IOR catalyst gradually increase with the increase of MnOx loading amount within a specific working temperature range (<200 °C). When MnOx loading amount x is 0.43, the NOx conversion is up to 85% at most. The low temperature NH3-SCR activity of Mnx/IOR catalyst can be enhanced remarkably by introducing cerium. The NOx conversions of Mn0.43-Cey/IOR catalyst at the operating temperature range (<200 °C) increase steadily with the cerium adding amount increasing. All the Mn0.43-Cey/IOR catalysts show excellent denitrification efficiency (more than 90%) at about 160 °C. Compared with Mn0.43/IOR catalyst, Mn0.43-Ce0.1/IOR shows excellent denitrification performance and application prospect because of its higher manganese valence state, enhanced redox capacity, larger specific surface area, and significantly improved surface acidity and anti-SO2 poisoning ability.