Nanofiltration (NF) is crucial for advancing water purification and wastewater reuse technologies. Incorporating biocidal nanoparticles (NPs) such as AgNPs and CuNPs is promising for developing antibacterial and antibiofouling NF membranes, while their application is limited by NPs aggregation, high cost, and severe ion release. In this study, we developed novel NF membranes by integrating bimetallic AgCu nanoalloys via an in-situ reduction and coordination method facilitated by a polydopamine/polyethyleneimine (PDA/PEI) intermediate layer. The sequential deposition of Cu²⁺ onto nascent AgNPs formed uniform AgCuNPs with a unique core-shell structure. The Cu shell layer can shield the release of Ag⁺ from the Ag core and chelate with the PDA/PEI intermediate layer, thus controlling the release of biocidal ions and prolonging the biocidal properties of the membranes. As a result, the AgCuNP-modified membranes exhibited significantly improved membrane water permeability, salt rejection, and performance stability, along with reduced release of biocidal ions in the long-term operation. Notably, the bimetallic AgCuNP-modified membrane displayed superior antibacterial activity and biofouling reversibility compared to the commercial NF and monometallic Ag/Cu-modified membranes, achieving the highest sterilization rate (> 99%), largest flux recovery rate (93%), and lowest flux decline rate (16%) in both static antibacterial and dynamic biofouling processes. The metal-semiconductor heterostructure of the AgCuNPs facilitated the electron transfer from the Ag core to the Cu shell, intensifying the substantial generation of reactive oxygen species (H₂O₂: 71.6 mmol L^-1 m^-2, ^•OH: 43.4 mmol L^-1 m^-2, and O₂^•–: 1.3 × 10^-4) at the membrane-bacteria interface. The synergistic effects of the unique properties of AgCuNPs including microstructure, atomic composition, charge transfer, and ROS generation significantly enhanced the antibacterial capacity of the AgCuNP-modified membrane. This study presents a facile method for modifying NF membranes with bimetallic AgCuNPs to achieve enhanced antibacterial activity and biofouling reversibility, providing fundamental insights and promising potential for water treatment applications.

中文翻译：

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具有核壳结构的高稳定性双金属 AgCu 纳米合金，可在纳滤中可持续地减少抗菌和生物污垢


纳滤 （NF） 对于推进水净化和废水回用技术至关重要。掺入 AgNP 和 CuNP 等杀生物纳米颗粒 （NP） 有望开发抗菌和抗生物污染的 NF 膜，而其应用受到 NPs 聚集、高成本和严重离子释放的限制。在这项研究中，我们通过在聚多巴胺/聚乙烯亚胺 （PDA/PEI） 中间层的原位还原和配位方法整合双金属 AgCu 纳米合金，开发了新型 NF 膜。Cu²⁺ 连续沉积到新生的 AgNPs 上，形成了具有独特核壳结构的均匀 AgCuNPs。Cu 壳层可以屏蔽 Ag⁺ 从 Ag 核心释放并与 PDA/PEI 中间层螯合，从而控制杀生离子的释放并延长膜的杀生特性。结果，AgCuNP 改性膜表现出显着改善的膜透水性、脱盐率和性能稳定性，同时在长期运行中减少了杀生物离子的释放。值得注意的是，与商用 NF 和单金属 Ag/Cu 改性膜相比，双金属 AgCuNP 改性膜表现出优异的抗菌活性和生物污染可逆性，在静态抗菌和动态生物污染过程中均实现了最高的灭菌率 （> 99%）、最大的助焊剂回收率 （93%） 和最低的助焊剂下降率 （16%）。AgCuNPs 的金属-半导体异质结构促进了电子从 Ag 核心到 Cu 壳层的转移，加剧了活性氧的大量产生 （H₂O₂： 71.6 mmol ^{L-1 m-2}， ^•OH： 43.4 mmol ^{L-1 m-2} 和 O₂^•–：1.3 × 10-4）。AgCuNPs 的独特性质（包括微观结构、原子组成、电荷转移和 ROS 生成）的协同作用显着增强了 AgCuNP 修饰膜的抗菌能力。本研究提出了一种用双金属 AgCuNP 修饰 NF 膜以实现增强抗菌活性和生物污垢可逆性的简单方法，为水处理应用提供了基本见解和有前途的潜力。