Utilizing blast-furnace dust as a novel persulfate catalyst for the efficient removal of petroleum contaminants from soil

Petroleum-contaminated soil (PCS) poses a significant health risk. Catalyst-activated persulfate presents a promising technology for efficient treatment, while magnetic activated carbon catalysts are increasingly recognized for their easy recovery and robust performance in advanced oxidation processes (AOPs). However, the complex and costly preparation process has limited its widespread implementation. In this work, blast-furnace dust (BFD), a solid waste from steel mill, was used as a novel persulfate catalyst for the total petroleum hydrocarbons (TPHs) removal from PCS. With the BFD/SP system (0.1 g BFD and 1 mM PS for per gram soil, 4:1 water-to-soil ratio, and 40 °C), removal rates of 88.10% and 84.39% were achieved for TPHs in 0.7% and 3.0% PCS, respectively, surpassing most reported persulfate AOPs, highlighting its superior efficacy. The main reason was that Fe/C components on BFD surface could cooperate to cyclically produce diverse reactive oxygen species, including SO4•−, OH•, O2•− and 1O2. Furthermore, the amphiphilicity of BFD could promote both pollutants and oxidants to converge to its surface simultaneously, effectively utilizing short-lived ROS to degrade TPHs. Our findings implies that BFD is an excellent SP activator, providing an innovative approach for PCS treatment and promoting sustainable utilization of BFD.