The integration of membrane separation with heterogeneous advanced oxidation processes is a prospective strategy for the elimination of contaminants during wastewater treatment. Fe-based catalysts and the green oxidant peracetic acid (PAA) are desirable candidates for the development of catalytic membranes because they are environmentally friendly. However, the construction of catalytic ceramic membranes (CMs) modified with efficient Fe-based catalysts that generate increased amounts of high-valent Fe-O species during PAA activation for the degradation of specific pollutants, especially during instantaneous membrane filtration, remains challenging. Herein, a single-atom Fe-based catalytic CM was fabricated and further optimized via the “electron enrichment + electron-transfer enhancement” method, which specifically refers to the simultaneous introduction of nitrogen vacancy (Nv) defects and the construction of ultrathin nanostructures. The CM-UCNv-Fe/PAA system exhibited outstanding bisphenol A (BPA) removal performance, with a first-order rate constant of 0.078 ms^-1 (4680 min^-1), which was 37 times greater than that of CM-BCN-Fe/PAA system (126 min^-1). In addition, the remarkable environmental adaptability, stability and low Fe leakage underscored its practical application potential. Mechanistic investigations revealed that Fe(V)=O was the predominant reactive oxygen species. Multi-scaled characterization and theoretical calculations confirmed that engineered Nv defects facilitated the construction of electron-rich single-atom Fe sites, which had the potential to supply more electrons. Porous ultrathin nanosheets exposed more Fe active sites, and many microinterfaces within the catalytic layers of the CM increased the possibility of contact between the Fe sites and PAA. The synergy of them enabled intensive electron transfer from Fe sites to PAA, which was the driving force for Fe(V)=O conversion during transient membrane filtration. In addition, the efficacy of the catalytic CM in municipal wastewater treatment and membrane fouling control were investigated. This work expands the research on the intensive electron transfer of a single-atom Fe-based catalytic CM for increased Fe(V)=O conversion via Nv defect introduction and ultrathin nanostructure construction.

中文翻译：

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用于城市污水处理的单原子铁基催化陶瓷膜的强电子转移：氮空位缺陷与超薄纳米结构的协同效应


膜分离与非均相高级氧化过程的集成是消除废水处理过程中污染物的前瞻性策略。Fe 基催化剂和绿色氧化剂过氧乙酸 （PAA） 是开发催化膜的理想候选者，因为它们对环境友好。然而，用高效的 Fe 基催化剂改性的催化陶瓷膜 （CM） 的构建仍然具有挑战性，该催化剂在 PAA 活化过程中产生更多的高价 Fe-O 物种以降解特定污染物，尤其是在瞬时膜过滤期间。本文通过“电子富集 + 电子转移增强”方法制备了单原子 Fe 基催化连续晶片，并进一步优化了该方法，该方法具体是指同时引入氮空位 （Nv） 缺陷和构建超薄纳米结构。CM-UCNv-Fe/PAA 系统表现出优异的双酚 A （BPA） 去除性能，一阶速率常数为 0.078 ^ms-1 （4680 ^min-1），是 CM-BCN-Fe/PAA 系统（126 ^min-1）的 37 倍。此外，其显著的环境适应性、稳定性和低 Fe 泄漏凸显了其实际应用潜力。机理研究表明，Fe（V）=O 是主要的活性氧。多尺度表征和理论计算证实，工程化的 Nv 缺陷促进了富电子单原子 Fe 位点的构建，从而有可能提供更多电子。 多孔超薄纳米片暴露了更多的 Fe 活性位点，CM 催化层内的许多微界面增加了 Fe 位点与 PAA 之间接触的可能性。它们的协同作用使电子从 Fe 位点到 PAA 的强烈电子转移成为可能，这是瞬态膜过滤过程中 Fe（V）=O 转换的驱动力。此外，还研究了催化 CM 在市政废水处理和膜污染控制中的功效。这项工作扩展了对单原子 Fe 基催化 CM 的密集电子转移的研究，以通过 Nv 缺陷引入和超薄纳米结构构建来提高 Fe（V）=O 转化率。