Optical Properties Of Plasma-Liquid System With Discharge In The Gas Canal With Liquid Wall And Secondary Discharge. Iu. Veremii, V. Chernyak, 1V. Naumov, V. Yukhymenk

Iu. Veremii, V. Chernyak, 1V. Naumov, V. Yukhymenko, N. Dudnyk.
Faculty of Radiophysics, Dept. of Physical Electronics, Taras Shevchenko Kyiv National University,
Glushkova st. 6, 03127, Kyiv, Ukraine; e-mail: tin@univ.kiev.ua.
1 Institute of Fundamental Problems for High Technology, Ukrainian Academy of Sciences
Prospect Nauki 45, Kiev 03028 Ukraine; e-mail: naumov@ifpht.kiev.ua
Abstract. Optical properties of plasma-liquid system with discharge in the gas canal with liquid wall and secondary
discharge were investigate. We used ethanol as experimental liquid and air as an initiating gas.The emission spectra of
plasma discharge in such system were analized. Also, we traced change of absorption coefficients in treated liquids.
Keywords: Dischsrge, plasma-liquid system, ethanol, emission, absorpsion.
PACS: 52, 52.77.-j
Heterophase plasma-liquid systems based on electrical discharges are of great interest today. Plasma is the source
of highly active particles, which are injected through the plasma-liquid boundary into the solution and stimulate
chemical transformations there. Typical plasma generators in such systems are electrical discharges with one or two
electrodes immersed into the liquid.
The main peculiarity of plasma-liquid systems is an intensive molecule flow from free liquid surface into the
discharge volume, which appears because of the evaporation and because of the producing of gaseous products of
plasmachemical processes. Therefore plasma generation in such systems occurs under pressure near saturated vapor
pressure and higher, when the ionization instability occurs in gas-discharge plasma. Secondary discharges in gasliquid
systems are of great interest. Using of auxiliary discharge inhibits development of the ionization instability in
plasma of the secondary discharge, provides high uniformity of parameters on the plasma-liquid boundary and
increases a number of external parameters of influencing on the plasma-liquid interaction in real plasmachemical
Secondary DC discharge supported by electrical discharge in gas channel with liquid wall in this work. The main
feature of such type of the discharge is large ratio of the square of plasma-liquid contact to plasma volume.
The plasma-chemical reactor (Fig. 1) consisted of the vertical cylindrical quartz test-tube supplied by two glass
inlet gas pipes (4) with coaxial electrodes (1, 2). The test-tube had a drain pipe at the bottom and an exhaust pipe at
the top. The reactor was filled by the work solution; the gas entered into the reactor through the inlet pipes. It formed
a counter-flow gas channel with a surrounding liquid wall in the volume between the immersed electrodes (gap
~5 mm) where an electrical breakdown occurred. The gas discharge was powered by the DC source (power ~100 W)
or HV source at typical frequency ~7 kHz (power ~30 W).. The auxiliary discharge in the liquid was burned between
the gas-discharge channel and liquid wall. The potential of the liquid wall was set by the voltage drop on the
secondary discharge powered by the DC source. This source links up via resistance to the one of the electrodes.

FIGURE 0. Plasma-liquid system with secondary discharge supported by electrical discharge in gas canal with liquid wall: 1 –
cathode of auxiliary discharge, 2 – anode of auxiliary discharge, 3 – “liquid” electrode of secondary discharge, 4 – glass pipes.
L, nm
I, a.u.
FIGURE 2. The typical emission spectrum of the discharge in the gas canal with liquid (ethanol) wall.
In a spectrum the group diffuse bands with main head at 405 nm is observed. Nowadays is convincingly proved,
that radiator of these bands is the molecule of three-nuclear carbon C3. These bands frequently connect to presence
of engendering carbon particles, therefore they can represent the certain interest in connection with study of the
mechanism of formation polymer nano-particles in plasma-liquid systems.
Plasma processing of liquid high-molecular hydrocarbons under normal conditions (in this case – ethanol) leads
to the synthesis of polymeric particles in our plasma-liquid reactor.
The plasma treated liquids was investigated by using UV-spectrophotometry. Structural changes in the materials
were determined by the comparison of the OAS spectra before and after the plasma treatment. It was found that the
absorption band with maximum near 330 nm appears in UV region of the spectra of treated ethanol and toluene
(curves 2 and 3 [1] on Fig. 3), which is typical for absorption spectra of fullerens, dissolved in unpolar organic
solvents (curve 1 [2] on Fig. 3).
From results of investigation of the plasma-liquid systems with secondary discharge, supported by the auxiliary
discharges, the following can be concluded, that the plasma-liquid systems on basis of the secondary discharges in
the gas channel with a liquid wall are perspective systems for development of new generation technologies of nanopolymeric
particle and reforming of liquid hydrocarbon with the purpose of free hydrogen generation.
1. Iu. Veremii, V. Yukhymenko, V. Chernyak, V. Naumov, V. Zrazhevskij, 1st Int. Conf. “Electronics and Applied Physics”,
Kyiv, Ukrain, 2005, pp. 51-52.
2. S.R. Wilson, Fullerenes: Chemistry, Physics and Technology, New York: John Wiley & Sons, 2000, pp. 437-465.

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