Enhanced Capture of Particulate Matter by Molecularly Charged Electrospun Nanofibers

We
introduce molecularly charged electrospun nanofibers obtained
by soft chemical treatment for the capture of particulate matter (PM).
These PMs, along with certain volatile organic compounds (VOCs), pose
a severe threat not only to human health but also to the environment.
As the concentrations of these PMs have been steadily increasing in
the Southeast Asian countries, a dire need for protection against
these particles is warranted. Filtering out the polluted air using
various filtration media, such as face masks and nasal filters, has
been the standard method for minimizing exposure to PM. Here, we demonstrate
the removal of PM and VOCs by utilizing electrospun nanofibers of
polystyrene (PS) and polyacrylonitrile (PAN) with molecular charges
imparted on them via chemical treatment. The chemically treated fibers
were successful in capturing even particles measuring 300 nm, which
are considered to be the most penetrable particles. We report a filtration
efficiency of ∼93% for removing such particles, which is ∼3
± 1.5% enhancement when compared to the untreated fibers. The
fibers have been subjected to extreme haze conditions (∼1413
μg m–3) of PM2.5 for a duration
of 1 h, and the filtration efficiency was measured to be ∼99.01%.
These fibers also possess the capability to capture model VOCs such
as aniline, toluene, tetrahydrofuran, and chloroform. When PAN, PS,
and their chemically treated counterparts were tested for their antibacterial
activity, these filter mats had bactericidal effect on Escherichia coli, Bacillus subtilis, and Enterococcus faecalis. A nasal
plug hosting these filter mats has been designed, which can offer
personal protection from PM. Enhanced removal of residual particles
is extremely important, and this difficult task is made possible with
our approach. The efficiency of our approach is due to the charged
nature of PM, especially of the smaller size regime.