Li Changyu, Wang Suo, Zhou Haoning, Gao Xianqiang, Shi Weijie, Ai Shiyun, Wu Jichun, Sun Yuanyuan
School of Earth Sciences and Engineering, Hydrosciences Department, Nanjing University, Nanjing, 210023, PR China.
College of Chemistry and Material Science, Shandong Agricultural University, Taian, 271018, Shandong, PR China.
Environ Res. 2025 Sep 13;286(Pt 2):122862. doi: 10.1016/j.envres.2025.122862.
Perfluorooctanoic acid (PFOA) poses a significant and persistent threat to groundwater due to its stability, high mobility, and carcinogenicity. Conventional permeable reactive barrier (PRB) fillers, like nano zero-valent iron (nZVI), face challenges including nanoparticle aggregation and passivation. To overcome these limitations, this study developed nitrogen-doped carbon-stabilized nZVI (nZVI@NC) using a scalable, solvent-free method combining mechanochemical ball-milling and pyrolysis. The synthesized core-shell nZVI@NC material effectively encapsulates nZVI within graphitic carbon, significantly improving its dispersion and reactivity (with an average crystallite size of 24.78 nm). A concentration of 100 mg/L of nZVI@NC adsorbed 83.5 % of PFOA within a 2-h timeframe, and the isotherms revealed an outstanding PFOA uptake capacity of 162 mg/g. Column experiments confirmed practical efficacy: using 50 mg nZVI@NC achieved complete PFOA removal (initial influent: 0.1 mg/L, Darcy velocity: 0.81 m/day) with no breakthrough for the first 1188 mL. Furthermore, a removal efficiency of 61.3 % was sustained in actual groundwater. Mechanistic studies (XPS, SEM-EDS, AIMD simulations) revealed a biphasic adsorption process: an initial rapid phase driven by physicochemical interactions, followed by a diffusion phase governed by pore embedding. This work establishes nZVI@NC as an efficient, scalable, and high-performance PRB filler for sustainable in situ remediation of PFOA-contaminated groundwater.
全氟辛酸（PFOA）因其稳定性、高迁移性和致癌性，对地下水构成了重大且持久的威胁。传统的可渗透反应屏障（PRB）填料，如纳米零价铁（nZVI），面临着包括纳米颗粒聚集和钝化在内的挑战。为了克服这些限制，本研究采用机械化学球磨和热解相结合的可扩展、无溶剂方法，开发了氮掺杂碳稳定的nZVI（nZVI@NC）。合成的核壳结构nZVI@NC材料有效地将nZVI包裹在石墨碳中，显著提高了其分散性和反应活性（平均微晶尺寸为24.78 nm）。在2小时内，100 mg/L的nZVI@NC对PFOA的吸附率达到83.5%，等温线显示其对PFOA的吸附容量高达162 mg/g。柱实验证实了其实际效果：使用50 mg的nZVI@NC可实现对PFOA的完全去除（初始进水：0.1 mg/L，达西流速：0.81 m/天），在前1188 mL内无穿透。此外，在实际地下水中的去除效率维持在61.3%。机理研究（XPS、SEM-EDS、AIMD模拟）揭示了一种双相吸附过程：初始快速阶段由物理化学相互作用驱动，随后是由孔隙嵌入控制的扩散阶段。这项工作确立了nZVI@NC作为一种高效、可扩展且高性能的PRB填料，用于可持续原位修复受PFOA污染的地下水。
