Efficient degradation of anthracene in soil by carbon-coated nZVI activated persulfate

The easy passivation defect of nano zero-valent iron (nZVI) greatly limits its application in site pollution remediation. Carbon coating can effectively inhibit the passivation of nZVI, but its effectiveness in the soil is still unknown. This study investigated the feasibility of carbon-coated nZVI (Fe-0@C) as a persulfate (PS) activator to degrade anthracene (ANT) in soil. The results show that the Fe-0@C/PS system can remove 51.6% of ANT in the soil after 0.5 h of reaction, and reach 76.4% after 12 h of reaction. Not only that, the Fe-0@C/PS system shows a good removal effect on ANT within the initial pH range of 3-9. Free radical scavenging experiments show that superoxide radicals (O-2(center dot-)) and singlet oxygen (O-1(2)) are mainly responsible for the removal of ANT, while O-2(center dot-) may be mainly used as a precursor for the generation of O-1(2). The activation of PS by Fe-0@C can generate a large number of free radicals, and soil components (such as beta-MnO2) can promote the conversion of O-2(center dot-) to O-1(2). Furthermore, the possible degradation pathway of ANT was also proposed. The findings are of great significance to fill up the knowledge gaps in the application of nZVI in soil remediation.

Automated summary

In this study, the feasibility of carbon-coated nZVI (Fe-0@C) as a persulfate (PS) activator to degrade anthracene (ANT) in soil was investigated. The results showed that the Fe-0@C/PS system had a good removal effect on ANT in the soil, and the effectiveness was consistent across different pH ranges. The study also revealed the mechanism of action of superoxide radicals (O-2(center dot-)) and singlet oxygen (O-1(2)) in the removal of ANT, and proposed a possible degradation pathway for ANT, filling the knowledge gaps in the application of nZVI in soil remediation.