Electrospun PAN-HNTs composite nanofiber membranes for efficient electrostatic capture of particulate matters.

The fine particulate matter (PM) pollution has become a serious concern to public health. As the core part of PM air filters, high-performance electrostatic nanofiber membranes are urgently needed. However, the existing air filters remain challenging to further decrease the pressure drop to improve the wearer comfort. On the other hand, the rapidly disappearing static electricity of the existing electrostatic nanofiber inevitably gives rise to a relatively short service life. Here, we demonstrate a novel and enhanced electrostatic nanofiber membrane by introducing the halloysite nanotubes (HNTs) to the traditional electrospun PAN nanofiber membrane. The optimal PAN-HNTs nanofiber membrane shows a high removal efficiency of 99.54%, a low pressure drop of 39 Pa, and a high quality factor of 0.89 Pa. This greatly improved filtration performance can be attributed to the increased surface area and diameter of nanofiber after introducing the HNTs as additives with suitable doping concentrations. More importantly, compared with the pure PAN nanofiber membrane, the electrostatic capacity of the PAN-HNTs nanofiber membrane is significantly enhanced, which is confirmed by the leaf electroscope. After introducing the HNTs as additives, the surface of the PAN-HNTs nanofiber membrane becomes hydrophilic, which benefits for preventing foulants from attaching to the surface. We anticipate that the PAN-HNTs nanofibers as high-performance membrane air filters will bring great benefits to public health.