High-Temperature-Resistant\nDual-Scale Ceramic Nanofiber\nFilms toward Improved Air Filtration

Currently, air pollution primarily arises from industrial\nemissions,\ncoal combustion, and automobile exhaust, posing significant challenges\nfor mitigation. This highlights the urgent need for advanced and efficient\nfiltration materials with low pressure drop and high-temperature resistance.\nTraditionally, improving filtration property has involved increasing\nthe thickness of the filtration materials, which consequently leads\nto higher costs. Here, dual-scale mullite nanofiber (MNF) films containing\ninterwoven thick nanofibers (606 nm) and thin nanofibers (186 nm)\nare prepared using solution blow spinning. The dual-scale structure\ndesign enables the films to maintain a low pressure drop while achieving\nhigh filtration efficiency. At an airflow velocity of 5.3 cm s<sup>–1</sup>, the films with an areal density of 3.8 mg cm<sup>–2</sup>, achieve a filtration efficiency of 98.23% and a\npressure drop of 141 Pa for PM<sub>0.3</sub>. In addition, the MNF\nfilms exhibit excellent flexibility and high-temperature resistance,\nmaking them have great potential for use in high-temperature flue\ngas filtration.