Reactions between atomically precise noble metal nanoclusters (NCs) have been studied widely in the recent past, but such processes between NCs and plasmonic nanoparticles (NPs) have not been explored earlier....
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.
Conversion of polydispersed nanoparticles to their monodispersed analogues and formation of organized superstructures using them involve post synthetic modifications and the process is generally slow. We show that ambient electrospray...
We
present isotopic exchange reactions of atomically precise silver
nanoclusters (NCs) with materials of different dimensions, namely,
NCs, plasmonic nanoparticles (NPs), and bulk metals, all made of silver.
Isotopically pure 109Ag25(DMBT)18
– and 107Ag25(DMBT)18
– (DMBT is 2,4-dimethyl benzene thiol) were reacted
with Ag NPs of different sizes in the range of ∼2–11
nm, protected with the same ligand. The exchange of 107Ag/109Ag atoms in the NC was monitored using electrospray
ionization mass spectrometry. The reaction kinetics was analyzed by
fitting the temporal evolution of the reactant concentration to a
kinetic model. The reaction timescales of NC–NP reactions were
significantly longer compared to those of the NC–NC exchange
process under similar conditions. Differences between NC–NC
exchange and NC–NP exchange highlighted the importance of the
structure in controlling the reaction. Moreover, isotopic exchanges
of the NC were also studied with the bulk metal to obtain a complete
understanding of how the kinetics of atom transfer varies upon changing
the size of the reacting partner from nanoscale to bulk.
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