Graphene oxide induced thermal-oxidation polyacrylonitrile nanofibrous membrane with superior heat resistance and flame retardancy for high-temperature air filtration

Direct removal of particulate matter (PM) from high-temperature emission sources is essential for efficient and energy-saving air filtration, which necessitates air filter materials with heat resistance and flame retardancy. Nanofibrous membranes prepared by electrospinning technology have been extensively studied for air filtration. However, the scarcity of easily processable electrospinning materials with heat-resistant and flame-retardant properties results few reports on high-temperature air filtration (100–350 °C). In this study, a graphene oxide induced thermal-oxidation polyacrylonitrile (GO-OPAN) nanofibrous membrane is prepared by heat treatment of graphene oxide-polyacrylonitrile (GO-PAN) nanofibrous membrane at 280 °C in air. The GO is verified to initiate the cyclization reaction during thermal oxidation process. The induction effect of GO prevents the melting and fusion of PAN nanofibers, as well as increases the heat resistant, flame retardancy, and PM filtration performance. The prepared GO-OPAN nanofibrous exhibits good heat resistant over 350 °C and exceptional flame retardancy with a limiting oxygen index (LOI) of 49.7 %. The GO-OPAN nanofibrous membrane shows efficient high-temperature air filtration performance. The PM_2.5 filtration efficiency at 350 °C is 98.16 %, the pressure drop is 158.7 Pa, and the quality factor is 0.025 Pa^-1. This work provides a guidance for the preparation of low-cost and easily processable nanofibrous membranes with heat-resistant and flame-retardant properties for high-temperature air filtration applications.