Activation of persulfate by highly dispersed FeCo bimetallic alloy for in-situ remediation of polycyclic aromatic hydrocarbon-contaminated soil

Abstract

Design of high-performance, environmentally friendly catalysts for remediation of contaminated soil is critical. Nano-zero-valent iron is widely used for this purpose and has high catalytic activity, but it readily agglomerates, which limits its use. To design efficient, environmentally friendly, and inexpensive soil remediation materials, we developed a Fe/Co-and nitrogen-doped carbon catalyst (FeCo/NC). The Fe and Co on the support were highly dispersed, many active sites were exposed, and the two metals exhibited synergistic catalytic effects. The ability to degrade anthracene in soil was evaluated through activating peroxodisulfate (PDS). The catalytic performance of the dual-doped catalyst was up to 24% more than that of catalysts doped with only Fe or Co. The FeCo/NC@PDS system efficiently removed 98.87% of anthracene from soil after 6 h. Moreover, the catalyst maintained excellent stability in both acidic and alkaline environments. The reaction mechanism was explored using radical quenching experiments combined with ESR spectra. In addition to a radical pathway involving OH, SO4−, and O2−, there was a non-radical pathway involving 1O2. The optimum conditions for use of the catalyst were determined, and possible degradation pathways for anthracene were proposed. This study provides data for the development of in-situ soil remediation catalysts.