关键词: 静电纺, 纳米纤维膜, 空气污染, 过滤材料, 多功能耦合, 个人防护, 工业净化

Abstract:

Significance The escalating severity of air pollution, particularly concerning fine particulate matter (PM_2.5/PM_0.1) and multipollutant interactions, necessitates the development of advanced air purification technologies. Traditional filter materials (such as glass fiber and electret meltblown fabrics) face limitations, including insufficient versatility in removing diverse air pollutants like microorganisms (bacteria), volatile organic compounds (VOCs), and ultrafine particulate matter (PM_0.1), as well as poor charge retention in humid environments. This underscores the requirement for air purification materials to possess multifunctional integration. Consequently, the development of high-efficiency air filtration materials featuring high dust loading capacity, low air resistance, and multifunctional synergy has emerged as a critical research direction in the field of fibrous filtration materials. This review emphasizes the critical need to develop electrospun nanofiber membranes (ENMs) with tailored multi-level structures, such as bead-on-string, wrinkled, and spider-web-like morphologies, to achieve synergistic filtration of particulates, microorganisms, and volatile organic compounds. Our work highlights the importance of integrating structural design with functional materials to enable high-efficiency, low-resistance, and multifunctional air purification, addressing a key gap in current environmental material science.

Progress Researchers have conducted extensive studies on the preparation of nanofibers using electrospinning technology and have determined that both the parameters of the spinning solution and the operational parameters of the electrospinning equipment are key factors governing the characteristics of the resulting nanofibers. Studies show that by adjusting solution properties (e.g., solvent ratio, polymer concentration) and processing parameters (e.g., humidity, voltage), structures such as bead-on-string, porous, core-shell, and dendritic fibers can be precisely controlled. These architectures significantly increase the specific surface area, optimize air flow pathways, and improve particle capture efficiency while reducing the pressure drop. For instance, bead-on-string structures enhance filtration efficiency (>97% for PM_0.3) with minimal air resistance, and spider-web-like nanonets achieve ultra-low resistance (18 Pa) under high-humidity conditions. Physical doping methods can simply and efficiently endow nanofibers with precisely controlled hierarchical morphologies. This further enhances filtration performance and simultaneously imparts functional properties such as antibacterial activity (e.g., using Ag NPs) and physical adsorption capacity (e.g., using ZIF-8 for volatile organic compounds adsorption) to the material. By innovatively preparing nanomembranes with composite multi-level structures, the synergistic integration of the advantages of different materials can be achieved. This optimizes the filtration mechanisms at the microscopic scale and significantly enhances the overall filtration performance against various pollutants. Composite multi-level structures have demonstrated integrated performance, e.g., simultaneous PM filtration, bacterial inhibition (>99%), and catalytic decomposition of volatile organic compounds (nearly 100% HCHO removal), marking a transition from single-function filters to intelligent, multi-pollutant control systems.

Conclusion and Prospect Electrospun multi-level structured nanofiber membranes offer a promising solution for efficient and multifunctional air purification, yet several challenges remain. 1) Understanding of airflow dynamics around individual nanofibers with different surface structures and their precise effects on airflow patterns, filtration efficiency, and pressure drop is still lacking. 2) The production cost of electrospun fiber membranes is currently high. Future research should focus on developing specialized polymer materials for electrospinning to enhance production efficiency, reduce costs, and meet industrial application demands. 3) Most solvents used in solution electrospinning are toxic. Therefore, research into water-soluble polymers or green, solvent-free melt electrospinning for nanofiber production is a promising avenue for developing future air filtration materials. 4) While the performance of single-structure nanofibers varies, preparing composite nanomembranes with diverse structures facilitates the synergistic combination of different material advantages. This approach optimizes the filtration mechanism at a microscopic level and significantly enhances comprehensive filtration performance against various pollutants. 5) To address complex air conditions, the integration of functionalities such as antibacterial activity, catalytic oxidation of volatile organic compounds, photocatalysis, and adsorption will define future trends in air filtration technology.

Key words: electrospinning, nanofiber membrane, air polution, filtration material, multifunctional coupling, personal protection, industrial purification