Microwave plasma removal of sulphur hexafluoride

Photodegradation of SF6 on polyisoprene surface: Implication on elimination of toxic byproducts

“…Intense infrared radiation absorption in the wave number ranging from 915 cm −1 to 960 cm −1 makes sulfur hexafluoride the second most potent green house gas [2]. Because of the considerable radiative forcing, extremely long life period [3] and rapid annual growth rate [4], SF 6 has been listed as one of the six primarily controlled pollutants in the atmosphere by the Kyoto Protocol.…”

“…The degradation of SF 6 had been achieved utilizing combustion, chemical-thermal catalysis and plasma methods [5][6][7], yet these technologies suffer either from high energy consumption or from the yield of especially toxic byproducts such as SF 4 , SF 2 , S 2 F 10 , SOF 2 , SOF 4 , SOF 10 , SO 2 F 2 , S 2 O 2 F 10 , HF and H 2 S [8,9]. Therefore an economically feasible approach that can eliminate SF 6 molecules effectively and generate less toxic products needs to be developed.…”

“…Whether radicals with unpaired electrons excited by UV light have similar effects as slow electrons is yet to be determined. According to reports [3,13], oxidative radicals such as O ( 1 D) and hydroxyl do not react with SF 6 because of the strong electron affinity of the fluorine atom. On the other hand, reductive radicals generated from propene that decompose SF 6 have been reported in our previous studies [14], yet the fouling on the surface of UV lamp caused by rapid photoinitiated radical polymerization and formation of toxic SiF 4 were found to hinder possible application of this technology to industry.…”

“…According to reports [3,13], oxidative radicals such as O ( 1 D) and hydroxyl do not react with SF 6 because of the strong electron affinity of the fluorine atom. On the other hand, reductive radicals generated from propene that decompose SF 6 have been reported in our previous studies [14], yet the fouling on the surface of UV lamp caused by rapid photoinitiated radical polymerization and formation of toxic SiF 4 were found to hinder possible application of this technology to industry. In this paper, reduction of SF 6 will be investigated in case of the reaction between SF 6 molecules and reductive radicals excited from natural rubber (NR)-a polymer constituted by repeating unit of 1,4-cis polyisoprene (PI).…”

Assessment of the Use of Nitrogen Trifluoride for Purifying Coolant and Heat Transfer Salts in the Fluoride Salt-Cooled High-Temperature Reactor

“…Alternative processes have been suggested Chang et al (2000) who describe an approach for destroying NF 3 using a barium titanate BaTiO 3 packed-bed plasma reactor and capturing the products from the plasma using a calcium carbonate CaCO 3 sorbent bed. Radoiu and Hussain (2009) describe an atmospheric microwave plasma for destroying SF 6 , another perfluorocompound used in the semiconductor industry for thin-film etching and cleaning CVD chambers. Hong et al (2006) describe the use of an atmospheric plasma torch to abate NF 3 and SF 6 .…”