Contrib. Plasma Phys. 36 (1996) 1, 51-61 The Conversion of NO x in a Corona Discharge with an Electrode Material Variation K. HENSEL, M. MORVOVÁ Institute of Physics, Faculty of Mathematics and Physics, Comenius University, Mlynská Dolina, F2, 842 15 Bratislava, Slovakia Abstract The spatial and surface chemical products and effectiveness of NO x removal (abbreviated deNO x ) under the corona discharge action at atmospheric pressure were investigated. The influence of high- voltage electrode material on a discharge character and the heterogeneous influence of the electrode surface are also reported in the article. The qualitative analysis was performed using infrared ab- sorption spectrometry. Special attention was paid to NO and NO 2 calibration measurements . 1 Introduction In the last decade, our life-sustaining environment has changed more rapidly than it did during any comparable period of history. Acid rain, global warming, the ozone layer depletion are the most important problems today. The environment is polluted by che- micals emitted directly from identifiable sources or by chemicals formed indirectly through photochemical reactions in the air [1]. All these chemicals have more or less toxic effects, endangering human health, therefore their removal or at least maintenance within a certain level is necessary. The nitrogen oxides are considered as very aggressive chemicals. In their effects on human, vegetation, animals and buildings, they are more toxic and aggressive than SO x (6-10 times) [2]. They are produced and released in the processes of combustion in the atmosphere, contributing to the photochemical smog production. Moreover, they are responsible for an acid rain, cause many serious diseases (bronchitis, pneumonia, heart diseases) and lower the resistance to influenza. In principle three methods are used for the reduction of NO x emissions from stationary sources: • Pre-combustion methods NO x emissions are reduced by cleaning fuels (e.g. coal) prior to combustion. In a catalytic process, the nitrogen in coal is transformed mainly to NH 3 . These methods have financial disadvantages. • Combustion modification methods The emissions are reduced by combination of various combustion modification techni- ques. Low NO x burners are designed to achieve two combustion stages, a low flame temperature, a low local oxygen concentration and a short residence time of flue gas in a higher temperature region [3]. However, this reduction is often insufficient to satisfy emission standards.