Nonradical activation of Oxone over Fe-doped nitrogen carbon (Fe@NC) armor catalysts for efficient degradation of anthropogenic phenolics (p-nitrophenol, 4-chlorophenol) in groundwater matrices

Iron-based catalysts are widely used in peroxysulfate-based AOPs but suffering from low catalytic performance at neutral pH conditions, which limits the application in groundwater remediation. Herein, this study investigated the efficacy, mechanism and long-term durability of Fe-doped nitrogen carbon (Fe@NC) armor catalysts toward peroxysulfate activation for the degradation of anthropogenic phenolics (APs) in groundwater matrices. The results showed that nonradical activation of Oxone (i.e., HSO 5 – ) was obtained over the as-prepared Fe-3 % @NC-700 catalyst, high-valent Fe species ( Fe(IV) O) and 1 O 2 were identified as the dominant reactive species for the efficient degradation of APs by experiments and density functional theory (DFT) calculations. Notably, the DFT results indicated that HSO 5 – was favorably adsorbed on the Fe atoms owing to the electrostatic interaction, which transformed exothermically into SO 4 2– and 1 O 2 over Fe 3 C, accompanied by the generation of Fe(IV) O. Additionally, the Fe-3 % @NC-700 catalyst displayed long-term activity for in situ activation of Oxone in groundwater matrices without pH adjustment, resulting in ΔAPs: ΔOxone stoichiometry efficiencies at 4.2–5.0 % . Wheat seeds germination tests revealed that the biotoxicity of the treated water was reduced notably by the present catalytic system, which holds large potential application in treatment of APs-contaminated groundwater.