| dc.description.abstract | Due to the extremely high global warming potential (GWP). Emissions of perfluorinated compounds (PFCs) have coused attracted more and more public concern due to their high global warming potential (GWP). Since Kyoto Protocol has come into effect, more efforts need to be made to develop abatement technologies with better performance to effectively reduce PFC emissions.
Among the various strategies for PFC removal, destruction is still the most available one. Combustion and catalytic oxidation are commonly used approaches for reducing PFC emissions. However, relatively high fuel cost and potential poisoning of catalyst limit their further application. Non-thermal plasma (NTP) technologies have been successfully demonstrated to be effective in removing a variety of gaseous pollutants, such as NOx, SOx, VOCs, and PFCs. More recently, a promising technology referred to as combined plasma catalysis (CPC) has been developed. The better performance for synthesis gas production and pollutant destruction has been proved in relevant literature. However, the interaction between plasma and catalysis is not fully understood.
This study aims at investigating the difference in the destruction mechanisms as well as the change of catalyst surface properties after plasma treatment of SF6 and CF4 in DBD and CPC, respectively.
The experimental results indicate that the rougher surface of catalyst after plasma treatment could enhance catalysis, which might result from the catalyst activity due to the increment of active sites on the edges and corners. On the other hand, after treating gas stream containing SF6 with CPC, formation of S on the catalyst surface has been confirmed. In terms of catalysis, such phenomenon will cause negative effect because some active sites are covered with S. Moreover, substances such as CuS2, ZnSO4, AlF3 and MgF2 are also identified on the catalyst surface after plasma treatment.
The highest removal efficiencies for SF6 and CF4 obtained with DBD are 93% and 32%, while those achieved with are CPC are 85% and 59%, respectively. It is interesting to find that the removal efficiency for SF6 obtained with DBD is higher that with CPC under the same specific energy density is found in this study. Based on the experimental results of this study, it might stem from the reverse reaction taking place on the surface of catalyst. As for the by-product analysis, the results indicate that SO2F2 and SOF4 are the major products after plasma treatment of SF6. | en_US |