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Mater Sci Nanotechnol 2017 | Volume 1 Issue 2
allied
academies
Nanomaterials and Nanochemistry
November 29-30, 2017 | Atlanta, USA
International Conference on
G
enerating a pulsed submerged arc (SA) within a liquid
produces a plasma bubble comprised of ionized
material evaporated from the electrodes and the liquid. This
plasma bubble serves as a microplasma reactor in which
radiation, active chemical species, and nano-particles are
produced. The arc discharge may be initiated by high voltage
breakdown, or by mechanically breaking contact between
current carrying electrodes and drawing an arc; the initiation
method influences the type of particles produced and the
energy expended. Micro- and nano-particle production was
studied using pulsed arcs submerged in ethanol and water.
Drawn arc initiation tended to produce a larger proportion of
micro-particles than with breakdown initiation. The micro-
particles tended to be comprised mostly of the electrode
material, while nano-particles tended more to incorporate
material from both the electrodes and the liquid. Particularly
interesting were: (a) Ni nano-particles produced with Ni
electrodes in ethanol, in which the Ni was supersaturated
with dissolved C, and enveloped with a protective C outer
layer, and (b) pure C nano-particles produced with graphite
electrodes in ethanol, including nano-onions and magnetic
C nano-particles. UV radiation and OH radicals produced
by the SA disinfected water was inoculated with E. coli
bacteria. Treatment of 50 ml of water containing 2×104
c.f.u./ml of bacteria for 5s with 48 mJ pulses applied at a
100 Hz repetition rate produced a survival rate of <5×10-
4 with an energy expenditure of 0.14 kW-hr/m
3
. Water
contaminated with various organics, including Methylene
Blue (MB), Sulfadimathoxine (SDM) antibiotic, phenol, and
effluents from various industrial plants, was treated with a
drawn arc initiated SA using C, Fe, Ti, and Cu electrodes, and
their combinations, both without and with the addition of
(0.01-0.5%) H
2
O
2
. The treated solutions were examined by
Raman and absorption spectroscopy. Particles produced
during the arc treatment were studied by SEM, XPS and
XRD. It was found that MB was decomposed both during and
after arc treatment. The produced nano-particles defined
the character of the pollutant removal and the level of the
removal ratio after SA treatment. With C electrodes, the
MB concentration exponentially decreased for the duration
of the treatment, while with the other electrodes the MB
concentration saturated. The saturation is explained by a
decrease of the oxidative species concentration with SA
treatment time for these electrodes. Aging of the solutions
after the SA treatment with all combinations of electrodes in
the presence of H
2
O
2
removed ~99% of the MB contaminant.
The decomposition during aging may be associated with the
accumulation of oxidative species, particularly peroxides, on
the surface of eroded particles that gradually oxidized the
MB. The association of particles with the decomposition
of impurities is supported by faster decomposition in
cases where the particle diameters were smaller. An MB
decomposition yield of G99.6=90 g/kWhr was obtained using
SA with Ti and Fe electrodes and 0.5% H
2
O
2
addition. SA was
successfully applied to treating industrial waste water from
a pharmaceutical plant and decomposing phenol dissolved
in water.
e:
boxman@eng.tau.ac.ilPulsed submerged arc nanoparticle synthesis, disinfection and decontamination
R L Boxman
Tel Aviv University, Israel