Experimental and simulation analysis on by-products of treatment of SF6 using dielectric barrier discharge

Dielectric barrier discharge (DBD) plasma is a simple technology with low energy consumption and high efficiency for treating gas waste. In this paper, DBD was used to remove greenhouse gas sulfur hexafluoride (SF<inf>6</inf>). The degradation by-products of SF<inf>6</inf> were detected and they were SOF<inf>4</inf> (with highest concentration), SO<inf>2</inf>F<inf>2</inf>, SOF<inf>2</inf>, and a limited amount of SO<inf>2</inf>. The thermodynamics associated with DBD degradation of SF<inf>6</inf> at ambient temperature and atmospheric pressure was studied. The calculations showed that SF<inf>6</inf> molecules can be dissociated step by step by high-energy electrons. The effect of traces of water vapor in the reactor was considered. Free radicals such as H and OH can be generated by the dissociation of H<inf>2</inf>O, which requires about 96.64 kcal/mol. Once SF<inf>6</inf> and H<inf>2</inf>O molecules breaks down, their intermediate products can react with each other easily to form the final by-products, including SO<inf>2</inf>, HF, SOF<inf>2</inf>, SOF<inf>4</inf> and SO<inf>2</inf>F<inf>2</inf>. Most of these formation reactions were thermodynamically favorable. The reaction pathways and reaction energy well explained the difference in the yield of by-products in the DBD experiment.

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