Insight into blast furnace dust for selective catalytic reduction of NOx: An experimental and DFT study

Abstract

Blast furnace dust (BFD), a solid waste generated from the ironmaking process, causes the environmental problems of soil and water pollution. In this work, we develop the selective catalytic reduction (SCR) catalyst for the nitric oxides (NO) reduction using BFD as the raw material by the co-precipitation method. To guarantee the strongest catalytic capability, different calcined temperatures are tested to activate the catalysts, where the prepared catalysts are labeled as BFD-T with the capital letter T to represent the calcination temperature. α-Fe2O3 is the main crystal phase in BFD-T catalyst and the mesoporous structure is mainly concentrated in 2–15 nm. The BFD-400 catalyst presents the best SCR performances and further increasing of the calcination temperature for the catalyst preparation reduces the reducibility, specific surface area and surface adsorbed oxygen of the catalyst. In the temperature range of 225 ℃ to 350 ℃, the BFD-400 catalyst presents the nitrogen oxides (NOx) conversion of more than 90%, which is attributed to the increase of ferric ion on the catalyst surface. Meanwhile, density functional theory (DFT) is applied to study the adsorption states of the reactant molecules on the catalyst surface and reaction mechanism. During the SCR process, this catalyst shows the excellent resistance to sulfur and water in the coal-fired flue gas due to the weak adsorption energy calculation.