Synthesis of nanocrystalline iron oxides with mesostructure as desulfurizer

Nanocrystalline iron oxides with mesostructure were synthesized via solid state-reaction method at ambient temperature. Its desulfurization performance was investigated using flue gas with high space velocity and high concentration of H2S. The results demonstrated that structure-directing agents contributed larger surface area, more mesopores and smaller crystal size to the iron oxides. More surface hydroxyl groups were observed on the samples prepared by polyethylene glycol (PEG). The sulfur capacity is strongly influenced by the pore structure and hydroxyl groups of the iron oxides. The pores with diameters between 2 and 4.5 nm are the most active ones for removal of H2S and surface hydroxyl groups are beneficial to the improvement of sulfur capacity. Of note is that the higher single-stage sulfur capacity is achieved for the synthesis desulfurizers compared with the commercial ones.

► Nanocrystalline iron oxides with mesostructure can be synthesized with solid state-reaction method.
► The effect of pore structure on sulfur capacity was investigated.
► The sulfur capacity may be relevant to the surface hydroxyl groups of iron oxide.
► Higher sulfur capacity of iron oxides is obtained in the presence of PEG.