A Cleanable Self-Assembled Nano-SiO2/(PTFE/PEI)n/PPS Composite Filter Medium for High-Efficiency Fine Particulate Filtration

A silicon dioxide/polytetrafluoroethylene/polyethyleneimine/polyphenylene sulfide (SiO2/PTFE/PEI/PPS) composite filter medium with three-dimensional network structures was fabricated by using PPS nonwoven as the substrate which was widely employed as a cleanable filter medium. The PTFE/PEI bilayers were firstly coated on the surfaces of the PPS fibers through the layer-by-layer self-assembly technique ten times, followed by the deposition of SiO2 nanoparticles, yielding the SiO2/(PTFE/PEI)10/PPS composite material. The contents of the PTFE component were easily controlled by adjusting the number of self-assembled PTFE/PEI bilayers. As compared with the pure PPS nonwoven, the obtained SiO2/(PTFE/PEI)10/PPS composite material exhibits better mechanical properties and enhanced wear, oxidation and heat resistance. When employed as a filter material, the SiO2/(PTFE/PEI)10/PPS composite filter medium exhibited excellent filtration performance for fine particulate. The PM2.5 (particulate matter less than 2.5 μm) filtration efficiency reached up to 99.55%. The superior filtration efficiency possessed by the SiO2/(PTFE/PEI)10/PPS composite filter medium was due to the uniformly modified PTFE layers, which played a dual role in fine particulate filtration. On the one hand, the PTFE layers not only increase the specific surface area and pore volume of the composite filter material but also narrow the spaces between the fibers, which were conducive to forming the dust cake quickly, resulting in intercepting the fine particles more efficiently than the pure PPS filter medium. On the other hand, the PTFE layers have low surface energy, which is in favor of the detachment of dust cake during pulse-jet cleaning, showing superior reusability. Thanks to the three-dimensional network structures of the SiO2/(PTFE/PEI)10/PPS composite filter medium, the pressure drop during filtration was low.

Durable nanocomposite face masks with high particulate filtration and rapid inactivation of coronaviruses

The COVID-19 pandemic presents a unique challenge to the healthcare community due to the high infectivity rate and need for effective personal protective equipment. Zinc oxide nanoparticles have shown promising antimicrobial properties and are recognized as a safe additive in many food and cosmetic products. This work presents a novel nanocomposite synthesis approach, which allows zinc oxide nanoparticles to be grown within textile and face mask materials, including melt-blown polypropylene and nylon-cotton. The resulting nanocomposite achieves greater than 3 log10 reduction (≥ 99.9%) in coronavirus titer within a contact time of 10 min, by disintegrating the viral envelope. The new nanocomposite textile retains activity even after 100 laundry cycles and has been dermatologist tested as non-irritant and hypoallergenic. Various face mask designs were tested to improve filtration efficiency and breathability while offering antiviral protection, with Claros’ design reporting higher filtration efficiency than surgical masks (> 50%) for particles ranged 200 nm to 5 µm in size.

Durable Nanocomposite Face Masks with High Particulate Filtration and Rapid Inactivation of Coronaviruses

The COVID−19 pandemic presents a unique challenge to the healthcare community due to the high infectivity rate and need for effective personal protective equipment. Zinc oxide nanoparticles have shown promising antimicrobial properties and are recognized as a safe additive in many food and cosmetic products. This work presents a novel nanocomposite synthesis approach, which allows zinc oxide nanoparticles to be grown within textile and face mask materials, including melt-blown polypropylene and nylon-cotton. The resulting nanocomposite achieves greater than 3 log 10 reduction (≥ 99.9%) in coronavirus titer within a contact time of 10 minutes, by disintegrating the viral envelope. The new nanocomposite textile retains activity even after 100 laundry cycles and has been dermatologist tested as non-irritant and hypoallergenic. Various face mask designs were tested to improve filtration efficiency and breathability while offering antiviral protection, with Claros’ design reporting higher filtration efficiency than surgical masks (> 50%) for particles ranged 200nm to 5µm in size.

Nonwoven characteristics effective for blood-resistant particulate filtration for healthcare application

The epidemic virus such as COVID-19 can spread via bioaerosol or droplets, and the use of filtering facepiece is crucial in reducing the opportunity of infection. For healthcare application of filters, the fluid penetration resistance is an additional benefit. In this study, nonwoven characteristics that affect the blood penetration resistance were analyzed, using different coverweb materials including electrospun and spunbond webs. The web properties were varied in the basis weight, porosity, and wettability. The blood penetration resistance was tested using the horse blood and human blood simulant at the stream velocity of 2.83 m/s. The blood resistance was affected by both the surface wettability and the physical parameters. When the coverweb and the filter web were hydrophobized, filtration efficiency against oily aerosol was enhanced, without interfering comfort properties. This study is novel in that the comprehensive effects of physical and wetting properties were investigated in terms of fluid penetration resistance, comfort properties and filtration performance.

Impact of Using a Filter in a Direct Gasoline Injection Engine Exhaust System on the Emitted Particle Mass and Number

The article presents emission test results comparison carried out on a dynamic engine dynamometer. Parameters were recorded during a drive made in accordance with the requirements of the RDE. Test bench allowed to determine the particle mass and number emission in the repetitive engine operation conditions. One of three used elements wan an OEM solution from one of particulate filters producers, the other was intended for use in original systems, the third was a custom product. The highest efficiency of particulate filtration was demonstrated by the last filter, which was adapted to the engine.