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

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Switzerland : 1996), 2023-12, Vol.477, p.146920, Article 146920
• Main Authors: Su, Lei, Li, Yifan, Wang, Zhenkai, Lou, Yao-Yin, Zheng, Qi-Zheng, Wu, Zhangxiong, Sun, Sheng-Peng
• Format: Article
• Language: English
• Subjects: Fe(IV)=O; Fe@NC armor catalyst; Groundwater treatment; Oxone activation; Phenolic pollutants
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2023.146920

[Display omitted] •Fe doping greatly enhanced the activity of NC catalysts toward Oxone activation.•Generation of Fe(IV)=O and 1O2 were identified by experiments and DFT calculations.•Phenolic compounds were efficiently degraded with a notable decrease in biotoxicity.•The prepared Fe-3%@NC-700 catalyst had a long-term activity for Oxone activation. 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., HSO5–) was obtained over the as-prepared Fe-3 % @NC-700 catalyst, high-valent Fe species (Fe(IV)O) and 1O2 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 HSO5– was favorably adsorbed on the Fe atoms owing to the electrostatic interaction, which transformed exothermically into SO42– and 1O2 over Fe3C, 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.