XRD/SEM/EDS Analysis of Iron Surface after NO Reduction with CH₄ in N₂ and SO₂ Atmosphere

Abstract

NO reduction by iron was conducted in a one-dimensional ceramic tubular reactor at 300 - 1100 °C in N2and simulated flue gas atmosphere with 0.4% methane and 0.01%~0.04% SO2. The evolution of metallic iron was investigated by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and energy dispersive spectrum (EDS) methods. The results showed that SO2did not place negative effect on NO reduction by iron. XRD patterns showed that FeS was formed when there was SO2in the flue gas. The iron oxides were FeO and Fe3O4when methane was not and was used as reducing agent respectively. Rough and raised surface making up of a series of round smooth juts was formed over the iron surface after reaction with NO in N2atmosphere when there was 0.04% SO2. Porous surface consisting serried particles was formed when methane was used as reductant. White attachments were found locally on the iron surface when SO2existed in the flue gas, which was proved by EDS analysis to be FeS.