Highly Integrated Polysulfone/Polyacrylonitrile/Polyamide-6 Air Filter for Multilevel Physical Sieving Airborne Particles

Abstract

Rational structural design involving controlled pore size, high porosity, and particle-targeted function is critical to the realization of highly efficient air filters, and the filter with absolute particle-screen ability has significant technological implications for applications including individual protection, industrial security, and environmental governance; however, it remains an ongoing challenge. In this study, we first report a facile and scalable strategy to fabricate the highly integrated polysulfone/polyacrylonitrile/polyamide-6 (PSU/PAN/PA-6) air filter for multilevel physical sieving airborne particles via sequential electrospinning. Our strategy causes the PSU microfiber (diameter of ∼1 μm) layer, PAN nanofiber (diameter of ∼200 nm) layer, and PA-6 nanonets (diameter of ∼20 nm) layer to orderly assemble into the integrated filter with gradually varied pore structures and high porosity and thus enables the filter to work efficiently by employing different layers to cut off penetration of particles with a certain size that exceeds the designed threshold level. By virtue of its elaborate gradient structure, robust hydrophobicity (WCA of ∼130°), and superior mechanical property (5.6 MPa), our PSU/PAN/PA-6 filter even can filtrate the 300 nm particles with a high removal efficiency of 99.992% and a low pressure drop of 118 Pa in the way of physical sieving manner, which completely gets rid of the negative impact from high airflow speed, electret failure, and high humidity. It is expected that our highly integrated filter has wider applications for filtration and separation and design of 3D functional structure in the future.

A review of factors surrounding the air pollution exposure to in-pram babies and mitigation strategies

“…For example, the polar polymer nanofiber membrane has high capture efficiency, good optical transparency and low airflow resistance (Xu et al (2016). There is also a drive to integrate advantages of nano to microscale fibers to achieve optimal performance of air filtration techniques (Zhang et al (2016).…”

Green Electrospun Nanofibers and Their Application in Air Filtration

“…report a human‐friendly silk nanofiber air filter with superior filtration performance and basis weight compared to commercial microfiber air filters, which means great potential application in air filtration, especially for comfortable and personable protection. Ding's group did an excellent work in air filtration where the air filtration efficiency is very high while the pressure drop is extremely low; furthermore, the mechanical performance is very well . The filtration performance and mechanical properties reported in these literature were excellent; however, there still remains much room for further improvements such as the choice of green materials and solvent, the fabrication method, the modification of membranes, and the post‐processing of these membranes.…”

“…Ding's group did an excellent work in air filtration where the air filtration efficiency is very high while the pressure drop is extremely low; furthermore, the mechanical performance is very well. [147][148][149][150][151][152][153][154][155][156][157][158] The filtration performance and mechanical properties reported in these literature were excellent; however, there still remains much room for further improvements such as the choice of green materials and solvent, the fabrication method, the modification of membranes, and the post-processing of these membranes. In addition to facial masks, the electrospun nanofibrous membranes are expected to be used in protective clothing to safeguard people from biological or chemical hazards.…”

A method for assessing the performance of nanofiber films coated on window screens in reducing residential exposures to PM2.5 of outdoor origin in Beijing

“…Recently, scientists from the fields of nanoscience and nanotechnology have developed various nanofiber films for air filtration that show high particle removal efficiency and relatively low air resistance . Most of such work employed electrospinning to pull the polymer solution into a nanofiber and make it lie across the mesh holes of a supporting and adhering substrate .…”

“…The silk nanofiber filters achieve a PM 2.5 removal efficiency of 99% with a pressure drop of 98 Pa at a face velocity of 0.053 m/s. Ding's research group fabricated various nanofiber filters with different materials and combinations . For instance, the highly integrated polysulfone/polyacrylonitrile/polyamide‐6 (PSU/PAN/PA‐6) air filter attains a removal efficiency of 99.99% for particles with diameters ranging from 0.3 to 10 μm.…”