Degradation of PAHs in soil by activated persulfate system with activated carbon supported iron-based bimetal

Abstract

We developed a material of activated carbon (AC)-supported highly active iron-based bimetal (iron–copper bimetal/AC, Fe-Cu/AC) with high efficiency for polycyclic aromatic hydrocarbons (PAHs) degradation in soil by activating persulfate, benefiting from the synergistic effect that the characteristics of AC with porous carbon backbone, multiple active functional groups, high loading capacity and the characteristics of FeCu bimetal with high activity. The addition of Cu to the Fe-based/AC activator not only improved the dispersibility of Fe particles but also maintained the stability of the metal in the Fe-Cu/AC. The thermal activation (50 °C) promoted the degradation of PAHs by the Fe-Cu/AC-activated S2O82− system. Of the various systems tested, the Fe-Cu/AC-activated S2O82− system had the best degradation efficiency for 19 PAHs, with the overall efficiency following the order of Fe-Cu/AC + S2O82− > Fe-Cu + S2O82− > Fe-Cu/AC > S2O82−. The degradation mechanism of the Fe-Cu/AC-activated S2O82− system on soil PAHs showed that OH, OOH, and SO4− were the main active groups involved in the degradation of target PAHs. The target pollutants and their degradation products in the Fe-Cu/AC-activated S2O82− system indicated specific exposure pathways, providing a theoretical basis for the remediation of PAH-contaminated soil.