Fast Fabricating Cross-Linked Nanofibers into Flameproof Metal Foam by Air-drawn Electrospinning for Electrostatically Assisted Particle Removal

Air filtration is of vital importance for creating healthy breathing indoor air. Particle filters can cause relatively high air resistance and large energy consumption in building ventilation systems. Electrostatically assisted metal foam (EAMF) filters have been developed to provide relatively high efficiency with low air resistance. This study reported a method of fast fabricating cross-linked PVDF nanofibers inside nickel foams by air-drawn electrospinning. The improved EAMF-PVDF filter is flameproof, which provides high security in practices. The new filter increases the absolute efficiency for PM_0.3-0.5 (particulate matter between 0.3 and 0.5 μm in aerodynamic diameter) of the bare EAMF filter by 15% and keeps an average efficiency of 83.1% for 28-day filtering outdoor air at the filtering velocity of 1 m/s. Besides, the daily efficiency fluctuation of EAMF filter shrank from 27.3% to 3.4% after adding nanofibers. The fabricated nanofibers can be cleaned off by burning when reaching the life span, and then a repeated fast fabrication can regenerate the high efficiency. This work provides a new route to combining electrostatic stable polymer nanofibers with flameproof metal foam for fabricating air filters with high efficiency, low air resistance and fire resistance.