17 / 2023-12-16 19:44:14

Deciphering the microstructure of blast furnace dust and its impact on superior persulfate catalytic performance

Blast-furnace dust; Catalyzing persulfate; Fe/C components; combination modes of Fe and C

In advanced oxidation processes (AOPs), magnetic activated carbon catalyzed persulfate is gaining recognition due to its easy recovery and robust organic pollutant removal. However, the complex and costly preparation process has limited its widespread implementation. Blast furnace dust (BFD), rich in carbon and iron, is a solid waste of steel mill and demonstrates superior efficacy in catalyzing persulfate. The main reason is the Fe/C components on BFD surface could cooperate to cyclically produce diverse reactive oxygen species (ROS). Further analysis indicates that Fe in BFD primarily exists in the form of Fe₃O₄ or Fe₂O₃, while C predominantly appears as graphite and oxygen-functional groups. Both components efficiently catalyze persulfate to produce ROS. Iron oxides disperse, aggregate, or embed on planar or spherical carbon substrates, or within carbon voids. Dispersed distribution represents the primary form of iron oxides, while planar intercalation structures characterize the carbon substrate. These existing states facilitate the exposure of catalytic active sites. Additionally, besides the physical binding between Fe and C, a minor chemical binding is observed in the form of Fe-C-O, further enhancing ROS generation. These above combination modes of Fe and C induce more defect structures in the C element, which are beneficial for persulfate catalysis. Consequently, BFD exhibits excellent activation performance in persulfate catalysis. This work offers new insights into the microstructure of BFD and lays a theoretical foundation for optimizing catalyst preparation based on BFD, presenting a novel avenue for the value-added utilization of BFD.