Yue Nan, Yang Jiaxuan, Li Peijie, Zhao Qian, Wang Ying, Wang Zi, Ding Junwen, Wang Jinlong, Gong Weijia, Li Guibai, Liang Heng, Bai Langming
State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, China.
School of Engineering, Northeast Agricultural University, Harbin, 150030, China.
Water Res. 2025 Mar 15;272:122983. doi: 10.1016/j.watres.2024.122983. Epub 2024 Dec 16.
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 (4680 min), which was 37 times greater than that of CM-BCN-Fe/PAA system (126 min). 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.
膜分离与多相高级氧化工艺相结合是废水处理过程中去除污染物的一种前瞻性策略。铁基催化剂和绿色氧化剂过氧乙酸（PAA）是催化膜开发的理想选择，因为它们对环境友好。然而，构建高效铁基催化剂修饰的催化陶瓷膜（CMs），使其在PAA活化过程中产生更多高价铁氧物种以降解特定污染物，尤其是在瞬时膜过滤过程中，仍然具有挑战性。在此，通过“电子富集+电子转移增强”方法制备并进一步优化了单原子铁基催化CM，该方法具体指同时引入氮空位（Nv）缺陷和构建超薄纳米结构。CM-UCNv-Fe/PAA体系表现出优异的双酚A（BPA）去除性能，一级反应速率常数为0.078 ms⁻¹（4680 min⁻¹），是CM-BCN-Fe/PAA体系（126 min⁻¹）的37倍。此外，其显著的环境适应性、稳定性和低铁泄漏突出了其实际应用潜力。机理研究表明，Fe(V)=O是主要的活性氧物种。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铁位点的构建，这些位点有可能提供更多电子。多孔超薄纳米片暴露了更多的铁活性位点，CM催化层内的许多微界面增加了铁位点与PAA接触的可能性。它们的协同作用使铁位点向PAA发生强烈的电子转移，这是瞬时膜过滤过程中Fe(V)=O转化的驱动力。此外，还研究了催化CM在城市污水处理和膜污染控制方面的效果。这项工作扩展了关于单原子铁基催化CM通过引入Nv缺陷和构建超薄纳米结构实现强化电子转移以提高Fe(V)=O转化的研究。
