Flexible amorphous SiO2 fibrous filter for high-temperature air filtration

High-temperature air filtration requires filter that simultaneously offer thermal stability, high filtration efficiency, low airflow resistance, and mechanical integrity. However, conventional polymeric filters suffer from thermal degradation, while ceramic filters are often limited by brittleness and high pressure drop. Herein, a flexible silica (SiO 2 ) fibrous air filter (SAF) was developed through electrospinning followed by high-temperature calcination, providing a lightweight and permeable ceramic membrane for harsh filtration environments. Calcination at 900°C enabled the best balance between amorphous SiO 2 network formation and mechanical flexibility, while higher calcination temperatures induced inter-fiber sintering and brittleness. The optimized SAF filter exhibited a PM 0.3 filtration efficiency of 99.22% for PSL aerosols at a low pressure drop of ~65 Pa under an airflow rate of 5.3 cm s −1 . It also achieved an efficiency of > 97% for DEHS oily aerosols with a pressure drop of ~70 Pa. Continuous filtration tests demonstrated stable filtration efficiency over 1 h, and pressure drop maintained between 60 and 70 Pa. Moreover, the filtration performance retained unchanged after secondary heat treatment at 1000°C, and the SAF filter preserved their structural integrity under direct flame exposure at over 900°C. These results demonstrate that the flexible amorphous SiO 2 fibrous filter effectively bridges high-temperature resistance, high filtration efficiency, and low pressure drop, offering a promising membrane platform for particulate removal from high-temperature gases.