Fabrication of manganese-based Zr-Fe polymeric pillared interlayered montmorillonite for low-temperature selective catalytic reduction of NO by NH in the metallurgical sintering flue gas.

A series of Zr-Fe (Zr/Fe = 4:0, 3:1, 2:2, 1:3, 0:4) polymeric pillared interlayered montmorillonite loading 10 wt.% MnO (Mn/Zr-Fe-PILM) were investigated for the selective catalytic reduction of NO by NH (NH-SCR) in metallurgical sintering flue gas. The X-ray diffraction (XRD), N adsorption-desorption isotherm, scanning electron microscope (SEM), and ammonia temperature-programmed desorption (NH-TPD) were used to analyze the physicochemical property. The Fe polymerized with Zr exchanged to montmorillonite can improve the Mn/Zr-Fe-PILM low-temperature NO conversion and N selectivity. The Mn/Zr-Fe-PILM (1:3) shows the highest NO conversion between 140 and 180 °C. The XRD results suggest that the growth of crystalline ZrO phase is intensely restrained for the FeO migration into the ZrO lattice. The ZrO and MnO have an excellent dispersion in montmorillonite. The N adsorption result illustrates that the increase of Fe molar content in the Zr-Fe-PILM support increases the catalyst-specific surface area. The NH-TPD results elucidate that the Mn/Zr-Fe-PILM (1:3) has the most total acid sites. Therefore, the low-temperature catalytic activity of the Mn/Zr-Fe-PILM (1:3) has been assigned to the large specific surface area, abundant acid sites, and the dispersion of metallic oxides.