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.

中文翻译：

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Oxone on Fe 掺杂氮碳 （Fe@NC） 装甲催化剂的非自由基活化，用于高效降解地下水基质中的人为酚类物质（对硝基苯酚、4-氯苯酚）


铁基催化剂广泛用于基于过氧硫酸盐的 AOP，但在中性 pH 条件下催化性能低，这限制了在地下水修复中的应用。在此，本研究研究了 Fe 掺杂氮碳 （Fe@NC） 装甲催化剂对过硫酸盐活化降解地下水基质中人为酚类物质 （AP） 的功效、机制和长期持久性。结果表明，在制备的 Fe-3 % @NC-700 催化剂上获得了 Oxone （即 HSO5–） 的非自由基活化，通过实验和密度泛函理论 （DFT） 计算确定高价 Fe 物种 （Fe（IV）O） 和 1O2 是高效降解 AP 的主要反应物种。值得注意的是，DFT 结果表明，由于静电相互作用，HSO5– 被很好地吸附在 Fe 原子上，静电相互作用在 Fe3C 上放热转化为 SO42– 和 1O2，并伴有 Fe（IV）O 的产生。此外，Fe-3 % @NC-700 催化剂在地下水基质中显示出对 Oxone 的原位活化的长期活性，无需调节 pH 值， 导致 ΔAPs：ΔOxone 化学计量效率为 4.2–5.0 %。小麦种子发芽试验表明，目前的催化系统显著降低了处理水的生物毒性，这在处理 APs 污染的地下水中具有很大的潜在应用。