This study investigated the characteristics of an atmospheric pressure air-glow discharge with a liquid cathode. Distilled water was utilized as the cathode. The electric field strength, gas temperature as well as the emission intensity of some N 2 (C 3 u →B 3 g ) and OH (A 2 + →X 2 ) bands were measured at a discharge current ranging from 15 to 50 mA. Based upon the data obtained, the reduced electric field strength, E/N, and effective vibrational temperatures for N 2 (C 3 u , X 1 + g ) and OH (A 2 + ) were examined. The electron energy distribution function (EEDF) and some electron parameters (average energy, electron density and rate coefficients) were obtained based on a numerical solution of the Boltzmann kinetic equation. The result showed that the EEDF was not in equilibrium and the effective vibrational temperatures for N 2 (C 3 u , X 1 + g ) were essentially higher than the gas temperatures.

We investigated the characteristics of atmospheric pressure (AP) air glow discharge with aqueous electrolyte cathode. Distilled water or aqueous solutions of HNO 3 , KCl, KBr and KI were utilized as a cathode. The cathode voltage drop, electric field strength, gas temperature as well as emission intensity of some lines of OI, H, K, Na and bands of N 2 , OH, NO were measured at discharge current from 10 to 50 mA. The procedure of gas temperature measurement on the base of non-resolved structure of N 2 (C 3 u → B 3 g ) bands was described. The reduced electric field strength (E/N) was obtained, which showed that the discharge existed in the normal mode. On the base of these data, the regularities of optical emission were discussed.KEY WORDS: Atmospheric pressure plasma with aqueous electrolyte cathode; emission spectrometry; gas temperature.

This study investigated the processes for the destruction of phenol and its derivatives (resorcin and pyrocatechol) in aqueous solutions under the action of an oxygen dielectric barrier discharge (DBD) at atmospheric pressure in the presence or absence of catalysts in the plasma zone. It was shown that the DBD had a high decomposition efficiency for phenol and its derivatives (up to 99%). Phenol was the most stable and pyrocatechol was the least. In a plasma-catalytic hybrid process, the effective rate constants for phenol, resorcin and pyrocatechol decomposition were 11, 4 and 2.5 times higher, respectively, than those for the DBD treatment without catalysts. The process also resulted in a 1.4, 1.6 and 1.2 times higher rate of carboxylic acid formation for phenol, resorcin and pyrocatechol, respectively. The fractional conversion into the respective carboxylic acids reached 56% for phenol and 68% for resorcin and pyrocatechol.

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