Decomposition of Heptane by Dielectric Barrier Discharge (DBD) Plasma Reactor Having the Segmented Electrode: Comparison of Decomposition Mechanisms to Toluene

The effect of the structure of VOC and the exposed surface area on the decomposition of VOCs adsorbed on the zeolite by dielectric barrier discharge plasma were investigated. The decomposition mechanisms of heptane and toluene, which are chosen as a model reaction for alkane and aromatic VOC, respectively, were compared each other at the same experimental conditions in the plasma reactor having the segmented electrode. The comparison was discussed in terms of mineralization, CO₂ selectivity, ozone consumption, by-products, and energy yield. Also, the exposed surface area was expected to have a close relationship with the ozone consumption. The segmented electrode reactor could accelerate the dehydrogenation reaction at the low temperature as well as the atmospheric pressure without any support of catalyst. In each decomposition mechanism, the formation of hydrocarbon radical was considered as a key stage for decomposition of VOCs. The hydrocarbon radicals in the heptane decomposition were formed by the dehydrogenation, but that in the toluene decomposition were formed by the ring cleavage. The formation of hydrocarbon radicals could increase the active spots which could be attacked by the ozone, leading to the increased use efficiency of ozone. In conclusion, the toluene was decomposed easily when the similar energy was applied because the number of hydrogen atom was fewer.