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Electrospinning Machine| Sustainable Biomass-based Filter for High-efficiency PM0.3 Filtration

Views: 7484 Author: Nanofiberlabs Publish Time: 2025-08-19 Origin: Site

Fine particulate matter (PM0.3) is one of the air pollutants most likely to penetrate deep into the respiratory system. It can enter alveoli with inhaled air and even cross the blood-air barrier into the bloodstream, posing potential health risks and closely linking to various respiratory diseases. Currently, common air filter materials are mainly made from petroleum-based materials like polyester (PET) and polypropylene (PP). While these offer high filtration efficiency, they are difficult to degrade, creating significant environmental burdens. Converting agricultural waste into green, high-performance filter materials holds practical significance for rural economic development and achieving carbon neutrality goals.

Recently, a research team led by Professor Han Guangping from Northeast Forestry University has developed a dual-network filter material composed of interwoven micro-nano fibers using agricultural residues (zein and corn stover cellulose) through electrospinning technology. This innovative filter material does not rely on any petroleum-based polymers or toxic solvents, yet achieves exceptional PM0.3 removal efficiency (99.9994%) with low pressure drop (45 Pa), while being fully biodegradable in natural environments.The groundbreaking research, entitled "Sustainable Biomass-based Filter for High-efficiency PM0.3 Filtration," has been published in the prestigious journal Nature Communications. Wang Qingxiang, a Ph.D. candidate at Northeast Forestry University, serves as the first author of the paper. The corresponding authors include Professor Han Guangping, Professor Cheng Wanli, and Associate Professor Wang Dong from Northeast Forestry University; Professor Ding Bin from Donghua University; Researcher Zhang Shichao; Associate Professor Yue Yiying from Nanjing Forestry University; and Professor Wei Yan from Tsinghua University.

1.Fully Biomass-Based Design Enabling a Closed "Nature-to-Nature" Cycle

The filter material is synergistically constructed using corn protein (Zein) and straw-derived cellulose nanofibers (CNFs), both of which are naturally biodegradable components. The entire manufacturing process is completed solely in an ethanol-water system, requiring no addition of toxic organic solvents, metal salts, or surfactants, ensuring the material's green, safe, and environmentally friendly properties.Compared to traditional petroleum-based filter materials, this innovative material can undergo harmless and rapid degradation in natural environments after use without requiring recycling, truly achieving a green closed-loop lifecycle that embodies the concept of "from nature, back to nature." The design represents a significant advancement in sustainable material engineering by maintaining high performance while addressing end-of-life environmental concerns.

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Fig. 1: Sustainable preparation, fiber formation, and D-net structure.

2.Incomplete phase separation induces groove-fine fiber dual-network, enhancing PM0.3 capture

To regulate the microstructure of fibers, the research team has developed an incomplete non-solvent induced phase separation (incomplete NIPS) method based on dynamic solvent exchange behavior. In a high-humidity environment, ethanol rapidly evaporates from the surface of the jet, while water vapor slowly penetrates into the jet from the outside, creating a radial concentration gradient in the solvent system.Unlike the traditional NIPS which exhibits "phase separation upon contact", this solvent distribution drives a gradual phase separation process from the outside to the inside and does not immediately reach the critical threshold for zein precipitation. As the solvent gradient gradually forms, a slow and asymmetric solidification process occurs on the fiber surface: the cortical region collapses due to internal and external stress differences, and the retention of internal solvent further induces negative pressure and radial stress. Eventually, microscale fibers with grooved surfaces are generated, with an average diameter of approximately 2.6 ± 1.1 μm.Meanwhile, the added cellulose nanofibers (CNFs) significantly enhance the viscoelasticity and shear response of the system, prompting the main jet to split and form nanofibers with an average diameter of about 290 ± 180 nm. Fibers of the two scales are co-assembled to form a dual-network (D-net) structure consisting of micro-grooved fibers intertwined with nanofibers, which provides a structural basis for filter materials to achieve ultra-efficient PM0.3 filtration.

Scanning electron microscopy (SEM) and confocal microscopy results show that the viscoelastic difference induced by CNFs leads to the formation of deeper grooves on the surface of coarse fibers. This not only enhances the ability to embed and capture particles but also improves porosity, endowing the filter material with excellent dual capabilities of physical filtration and interfacial adsorption. The final D-net structured filter material features small pore sizes (mainly 1-4 μm, with some < 1 μm), effectively addressing the challenge that traditional filtration membranes "cannot block the finest particles".

Fig. 2: Structural properties of the corn-based membrane.

3.High efficiency, low pressure drop: Meeting commercial ultralow penetration standards

The grooved structure boosts particle embedding and entrapment, while the nanofibers offer a dense adsorption interface. Together, they synergistically establish an integrated mechanism of "embedding + filtration + adsorption".At an airflow velocity of 5.33 cm·s⁻¹, the D-net filter achieves a PM0.3 removal efficiency of >99.999% with a pressure drop of merely 45 Pa, complying with the standards for ultralow penetration air (ULPA) filter materials. Even under the high airflow velocity of 16.6 cm·s⁻¹, it still maintains a filtration efficiency of over 98.5%.More notably, the abundant polar functional groups (-OH, -C=O, -NH₂, etc.) in its structure grant it outstanding interfacial adsorption capacity. In terms of capturing formaldehyde—a small-molecule pollutant—it demonstrates far superior performance compared to commercial high-efficiency particulate air (HEPA) filters. The adsorption capacity per unit mass reaches 1.26 times its own weight, thereby forming a synergistically enhanced mechanism of "structural filtration + interfacial adsorption".

Fig. 3: Air filtration and formaldehyde adsorption mechanisms.

4.Full lifecycle assessment: 2-week degradation, outperforming petroleum filters

To comprehensively evaluate the environmental friendliness of this biomass-based filter material, the research team conducted a life cycle assessment (LCA) covering raw material collection, manufacturing, and waste disposal. The results indicate that the zein-based filter material outperforms traditional petrochemical-based filters by a large margin across multiple key environmental indicators.Compared with PET and PP filter materials, the zein-based filter reduces greenhouse gas emissions by 72.4% and 66.9% respectively, cuts mineral resource consumption by 83.7%, and lowers the risk of human non-carcinogenic toxic exposure by over 75%. It also shows significant advantages over traditional filters in other dimensions such as terrestrial ecotoxicity and marine eutrophication, fully demonstrating environmental benefits throughout the entire process from raw material acquisition to end-of-life disposal.Furthermore, this material requires no special recycling treatment. After being discarded, it can be directly degraded in the natural environment and completely decomposes in soil within 2 weeks—avoiding secondary pollution and energy waste caused by incineration or landfilling.

Fig. 4: Environmental feasibility and degradation tests.

Summary: The team proposed a green, high-performance filter strategy using agricultural waste via electrospinning. This biomass-derived D-net material matches or surpasses petroleum filters in performance while enabling a sustainable "nature-to-nature"闭环, offering a viable alternative for post-petroleum air filtration.

Paper link: https://www.nature.com/articles/s41467-025-61863-2

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Electrospinning Machine| Sustainable Biomass-based Filter for High-efficiency PM0.3 Filtration

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