| 摘要 |
PROBLEM TO BE SOLVED: To efficiently decompose sulfur hexafluoride by irradiating a gas contg. sulfur hexafluoride with light in the presence of a photocatalyst to decompose the sulfur hexafluoride. SOLUTION: A branch pipe 1a is provided to a waste CVD gas passage 1, a valve 1c is closed when the waste gas contg. sulfur hexafluoride flows in the passage 1, and the waste gas is introduced into a header 4 from a passage 3 by a pump. The waste gas is branched into several branch pipes, e.g. ten, in the header 4 and introduced into photochemical reaction units 5 each provided with a photocatalyst, and the sulfur hexafluoride in the gas is exposed to the UV of specified wavelength, passed through the unit 5 while in contact with the photocatalyst and decomposed. The gas purified by the decomposition of sulfur hexafluoride is again collected in a header 6, passed through a passage 7 and a branch pipe 1b and returned to the passage 1. The waste gas discharged from a CVD device and contg. sulfur hexafluoride is highly purified in this way. |
