Products analysis of low temperature surface discharge plasma processing of gaseous organic compounds by using GC-MS

Nonequilibrium low-temperature discharge plasma decomposition products of gaseous organic compounds (100-1000 ppm) contaminated in atmospheric pressure air, nitrogen or oxygen, such as chlorofluorocarbon (CFC-113), organic chloride (trichloroethylene) and carbontetrachloride, were studied for better understanding of the decomposition mechanism of plasma processing. A gas chlomato-mass spectrometer was used as a main analyzing equipment. When the decomposition rate is not so high (20-80%) for CFC-113, many various halogenated carbons or halogenated hydrocarbons are identified as intermediate products from CFC-113 by plasma processing. As the electric discharge power consumption increases, the decomposition rate of CFC-113 increases and intermediate products decrease. At the decomposition rate of more than 90%, some elemental products of hydrochloric acid, carbon dioxide and nitrogen suboxide are recognized as possible final products. On the other hand, if the environmental gas is pure nitrogen without any oxygen and water, the decomposition products are still intermediate with sufficient electric discharge power consumption indicating the existance of double decomposition mechanisms of nitrogen radicals and oxygen radicals. In the case of trichloroethylene decomposition, harmful intermediate decomposition products are observed when the decomposition rate is from 20 to 90%.<
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