Functionalized membranes for multipollutants bearing air treatment

Membrane technology has great potential application in gas–solid separation and air multipollutants purification. Although traditional technologies for dust removal have been widely developed, the shortcomings of low efficiency and high pressure drop are still the main challenges. Membrane technology provides a novel and effective approach for air pollutants control. Further, air multipollutants including ultrafine dust particles, volatile organic compounds (VOCs), nitrogen oxides, sulfur oxides, and microorganisms are targeted to be removed simultaneously, which requires the versatility of air purification membranes. In this chapter the basic theory of membrane-based gas–solid separation is firstly introduced, including the separation mechanism, structure characterization, and performance evaluation methods, followed by the introduction of the membrane materials for air purification, including biaxially stretched nanofiber membrane, electrospun nanofiber membrane, and ceramic membrane for gas–solid separation applications at medium and high temperatures. Finally, the review summarizes the synergistic purification of air multipollutants by coupling particulate matter (PM) filtration with denitrification, VOC degradation, desulfurization, and sterilization.