Air Filtration Membranes: Fabrication, Structures, Characteristics and Applications

Air pollution caused by particulate matter and toxic gases is violating individual’s health and safety. Nanofibrous membrane, being a reliable filter medium for particulate matter, has been extensively studied and applied in the field of air purification. Among the different fabrication approaches of nanofibrous membrane, electrospinning is considered as the most favorable and effective due to its advantages of controllable process, high production efficiency, and low cost. Advanced electrospinning techniques, including needleless, multi-needle and solvent-free electrospinning, have been proved capable of fabricating nanofibrous membranes at a rather high production rate, which is the foundation of large-scale production and widespread applications. The electrospun membranes, made of different materials and unique structures, exhibit good PM2.5 filtration performance of high filtration efficiency and low pressure drop, with multi-functions such as thermal stability, antibacterial functions and biodegradability. These membranes are applied to environmental protections and healthcare products against PM2.5, including filtration masks and filters. This chapter presents a brief overview of electrospinning techniques, different structures of electrospun nanofibrous membranes, unique characteristics and functions of the fabricated membranes, and summarization of the outdoor and indoor applications in PM filtration.