Decomposition treatment of SO₂F₂ using packed bed DBD plasma followed by chemical absorption

The technology of packed bed dielectric barrier discharge (DBD) plasma followed by a chemical absorption has been developed and was found to be an efficient way for decomposition treatment of sulfuryl fluoride (SO ₂F₂) in simulated residual fumigant. The effects of energy density, initial SO₂F₂ concentration, and residence time on the removal efficiency of SO₂F₂ for the DBD plasma treatment alone were investigated. It was found that the SO₂F ₂ could be removed completely when initial volume concentration, energy density, and residence time were 0.5%, 33.9 kJ/L, and 5.1 s, respectively. The removal mechanism of SO₂F₂ in the packed bed DBD reactor was discussed. Based on the detailed analysis of SO ₂F₂ molecular stability and its exhaust products in the DBD plasma reactor, it was concluded that the energetic electrons generated in the packed bed DBD reactor played a key role on the removal of SO ₂F₂, and the major decomposition products of SO ₂F₂ detected were SO₂, SiF₄, and S (Sulfur). Among these products, SiF₄ was formed by the F atom reacted with the filler-quartz glass beads (SiO₂) in the packed bed DBD reactor. Aqueous NaOH solution was used as the chemical absorbent for the gaseous products of SO₂F₂ after plasma pretreatment. It was found that the gaseous products in the plasma exhaust could be absorbed and fixed by the subsequent aqueous NaOH solution.