Nanofiber Air Filters with High-Temperature Stability and Superior Chemical Resistance for the High-Efficiency PM2.5 Removal

Constructing Stable Polyvinyl Alcohol/Gelatin/Cellulose Nanocrystals Composite Electrospun Membrane with Excellent Filtration Efficiency for PM2.5

Considering the high demand for air quality, the development of biomass-based air filtration membranes with high air filtration efficiency and good stability is an urgent task. In this work, polyvinyl alcohol (PVA), gelatin (GA), and cellulose nanocrystals (CNC) were mixed and prepared into a membrane through an electrospinning method for air filtration. After a hydrophobic modification, the modified PVA/GA/CNC composite membrane showed excellent filtration efficiency for PM2.5 (97.65%) through the internal three-dimensional structure barrier and the electrostatic capture effect of the CNC with a negative charge, as well as a low-pressure drop (only 50 Pa). In addition, the modified PVA/GA/CNC composite membrane had good mechanical properties (maximum tensile fracture rate of 78.3%) and high stability (air filtration efficiency of above 90% after five wash-filter cycles and a high-temperature treatment at 200 °C). It is worth noting that the whole preparation process is completed without organic solvents, putting forward a new strategy for the construction of green air filtration membranes.

Removal of the Homolog Tellurium of Polonium by SiO2 Nanofiber Filter for Lead Alloy-Cooled Reactors

The lead–bismuth eutectic (LBE) can be easily activated by neutron radiation to produce the radionuclide ²¹⁰Po. It is therefore necessary to establish an effective method to remove vaporized polonium in the cover gas to prevent its release into the air in scenarios of reactor maintenance and coolant leakage accidents. This paper presents a SiO₂ nanofiber membrane prepared based on the electrostatic spinning and calcination process. The SiO₂ nanofiber membrane had the advantages of good flexibility, high-temperature resistance, and corrosion resistance. In the trapping experiments, the SiO₂ nanofiber membrane filters showed excellent filtration performance at 300~400 °C, and the filtration efficiencies for Te, Pb, and Bi could reach 99%, 99%, and 98%, respectively. Proper filtration temperature and gas flow rate are important to maintain high filtration efficiency. After five cycles, the SiO₂ nanofiber membrane filter still exhibited excellent cycle-use performance. In the density functional theory (DFT) calculations, PbPo and PbTe had strong interactions with amorphous SiO₂, having adhesion energies of −2.96 to −2.83 eV/molecule.