Harmless Treatment Of SO₂F₂ With DBD Plasma

Sulfuryl fluoride(S02F2)is used increasingly around the world as a fumigant to replace methyl bromide.However,the hazards of SO2F2 have been given more attention.As an efficient atmospheric greenhouse gas,S02F2 must be removed without delay which has a serious impact on environment and human health.The technology of packed bed dielectric barrier discharge(DBD)plasma was used for the harmless treatment of residual S02F2 after fumigation.The process and experimental setup of harmless removal of SO2F2 have been established in this paper.The effects of electrical and process parameters on the removal efficiency of SO2F2 were investigated.Meantime,the removal mechanism of SO2F2 in the packed bed DBD reactor was also discussed.The effects of discharge voltage and energy density on the removal efficiency of S02F2 filled with different dielectrics were investigated.What's more,the removal products of SO2F2 filled with different dielectrics in the DBD reactor were analyzed.Results showed that SO2F2 could be removed efficiently in the packed bed DBD reactor when discharge voltage,diacharge frequency,energy density,electrode spacing,initial volume concentration and residence time were 11.4kV,8.0kHz,454J/L,7.5mm,0.5%and 5.1s,respectively.SO2F2 was mainly degraded into S02,SiF4 and S.The removal products of SO2F2 were absorbed by NaOH solution to realize harmless treatment.Based on the mechanism discussion,the removal of SO2F2 was attributed to the action of energetic electron generated in the packed bed DBD reactor,and the removal efficiency of SO2F2 depended on the number and energy of energetic electrons generated in the plasma reactor.Besides,alumina dielectric was more effective for SO2F2 harmless treatment,and SO2F2 could be completely removed when the energy density was above 208 J/L.Compared with filling quartz glass balls,the energy consumption of packing alumina ball decreased by more than 50%.In terms of alumina dielectric,the removal products after plasma treatment could be completely reacted and absorbed by alumina to realize the harmless treatment of SO2F2.In this paper,an efficient and feasible method was developed for the removal of SO2F2 after fumigation.These experiments provided the theoretical foundation to remove the exhaust with S and F atom.