Particulate matter damages engines of vehicles when blown into the ventilation system. Conventional engine-intake filter is cellulose microfiber board with an average diameter larger than ten microns, which has low removal efficiency of ultrafine particular matter. In this work, we apply ultrafine polyurethane nanofibers (∼122.8 nm) onto pleated cellulose board using scalable multinozzle electroblow spinning technology, which improves filtration efficiency of particulate matter with a diameter of less than 0.3 μm PM0.3 greatly. The thermoplastic polyurethane 85A nanofiber membranes are transparent, and display superior filtration performance which meets up with the 95% filtration efficiency standard in GB 19083–2010 technical requirements for protective face mask for medical use. The lightweight pleated thermoplastic polyurethane/cellulose composites intercept ∼90% ultrafine PM0.3 under airflow velocity of 32 L min–1 and possess great resistance to shock. These hierarchically designed filters follow a mechanical mechanism and can be used in on-road and off-road cars in the long run.

The demand for air filtration products has increased significantly with the aggravation of air pollution and the pandemic of coronavirus disease (COVID-19). It is urgently needed to develop an air filtration membrane that exhibits lasting filtration performance and antibacterial activity. Herein, we report a large-scale blow spinning technique to produce polyvinylidene fluoride (PVDF) nanofiber membranes for highly efficient air mechanical filtration and its antibacterial modification by adding the silver nanoparticles (AgNPs). The PVDF nanofiber membrane with an area density of only 1.0 g/m 2 exhibits the highest filtration efficiency of 98.63% for the particle with a size of 0.3 μm. After eliminating static electricity, there is almost no reduction in the filtration efficiency of particulate matter with a size larger than 1 μm and only 4.69% decrease in the particulate matter with a size of 0.5 μm. Hence, the PVDF nanofiber membrane with nanostructures for air filtration works mainly by the means of mechanical filtration. To inhibit the survival or growth of the intercepted bacteria on the membrane, the PVDF/AgNPs nanofiber membrane was fabricated by adding AgNPs to PVDF nanofibers, which exhibits the strongest antibacterial activity of more than 99% and an excellent filtration efficiency similar to that without adding AgNPs. The nanofiber membrane with antibacterial activity is expected to extend the service or storage time or be reused without loss of filtration performance. Additionally, large-scale production of nanofiber filtration membranes has been realized using a multi-needle blow spinning machine.

Developing adsorption materials for organic solvents with both high adsorption capacity and recyclability provides a broad prospect for contaminated water treatment. In this study, PI/SiO2 composite nanofibrous sponges with hydrophobicity, high oil adsorption capacity, and excellent cycling performance fabricated by blow spinning have been reported. The improvement of hydrophobicity of PISi-3 was credited to the SiO2 nanoparticles, resulting in excellent oil adsorption capacity (103.95 g/g for ethanol, 320.99 g/g for motor oil, and 386.81 g/g for silicone oil). The recyclability after 10 cycles of PISi-3 was improved by 23% compared with the pure PI sponge owing to the supporting effect of SiO2 nanoparticles. Sponges with higher cycling performance could be obtained by regulating the temperatures of thermal treatment. PISi-3 after heat treatment at 450 °C exhibited good oil adsorption ability (98.12 g/g for ethanol, 261.92 g/g for motor oil, and 315.81 g/g for silicone oil) and excellent cycling performance. The adsorption capacity decreased by only 0.22% after 10 cycles. Therefore, the fabrication strategy of the sponges has great prospects in maritime oil spill recycling and industrial water treatment.