Preparation of Multi-scale PI Nanofiber Membranes for High Temperature Air Filtration

Abstract

To address the insufficient efficiency of traditional filter materials in treating high-temperature waste gas from thermal power plants, a multi-scale polyimide (PI) nanofiber membrane was fabricated using a double-needle electrospinning system with polyamide acid (PAA) as the precursor. Experimental results identified solution concentration as the key factor controlling fiber diameter. Uniform coarse and fine fibers were successfully produced using spinning solution concentrations of 28 wt% and 36 wt%, respectively. Based on this characteristic, we have prepared multi-scale PI nanofiber membranes through conjugate electrospinning. Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA) confirmed the successful synthesis of PI. Mechanical testing revealed that multi-scale nanofibers exhibit better toughness. Filtration performance testing demonstrated that the membrane achieved 99.21% efficiency for 0.3 µm particles with an airflow resistance of only 67.7 Pa. Compared to pure coarse fiber membranes (58.4% efficiency, 30.3 Pa resistance) and pure fine fiber membranes (99.35% efficiency, 134.7 Pa resistance), this represents a high filtration efficiency and low airflow resistance. Furthermore, the multi-scale PI nanofiber membrane maintained stable filtration performance at 300 °C. This study provides a novel and practical solution for industrial high-temperature waste gas treatment.