High-performance SiO2 nanofiber membrane applied for high-temperature air filtration

This study is focused on the development of a foldable SiO2 membrane with a monodisperse fiber diameter of 300 nm, a flexible quartz crystalline phase, high mechanical strength, and excellent thermal stability up to 1000 °C. The fabrication process was scaled up using a pilot electrospinning equipment to produce a membrane with an area of approximately 2000 m2. At room temperature, the membrane with a basis weight of 12 g/m2 and a pressure drop of 271.5 Pa exhibited filtration efficiencies of 0.9957 for the MPPS (166 nm) and 0.9988 for PM0.3 (300 nm), resulting in quality factors of 0.020 and 0.025 Pa−1, respectively. To evaluate the performance of these membranes in high-temperature air filtration processes, 25 °C, 300 °C, and 400 °C were explored. Our results indicate a high influence on nanoparticle retention and pressure drop under such conditions. For fine particles, even a 5 g/m2 membrane showed the same efficiency as a HEPA filter with twice a low pressure drop and fifteen times a low basis weight. Compared to the commercial HEPA filters, our SiO2 membrane offered the same efficiency with superior permeability, resulting in lower energy consumption and longer filtration time to reach saturation capacity. In addition, manufacturing the membranes required a reduced amount of material per unit area, resulting in significant material savings.