Electrospun Nanofiber Membranes for Effective Air Filtration

Air pollution is now one of the leading causes of mortality every year across the world. The World Health Organization estimates that more than seven million people lose their lives every year due to exposure to direct and indirect air pollutants ( https://www.who.int/health-topics/air-pollution#tab=tab_1 ). In addition to particulate matter, the emergence of new airborne pathogens and diseases is also increasing the need to purify both indoor and outdoor air. Filtration is one of the most affordable and effective means to remove pollutants from the air. Air filters are made using multiple polymers in various forms and sizes. Having adequate porosity, pore size, and affinity that can provide mechanical strength and stability under various use conditions are some of the basic requirements for air filters. Among the various methods to produce air filters, electrospinning is one of the most promising approaches used to develop air filters from both natural and synthetic polymers. Air filters with considerably high filtration efficiencies, low pressure drops and high quality factors have been developed to remove particulate matter and also volatile organic substances. Natural polymers such as cellulose and starch and synthetic polymers such as poly(vinyl acetate), poly(acrylonitrile) (PAN), and poly(lactic acid) (PLA) have been electrospun into nanofibers for air filtration applications. However, the type of polymers used, the electrospinning conditions, and the additives present affect the properties and performance of the air filter membranes. This chapter intends to provide an overview of the types of polymers, conditions used and properties of the electrospun fibers and membranes obtained for air filtration applications.