Characteristics of aerosol by-products generated from sulfur hexafluoride treatment using ionizing energy

Decomposition of SF6 and its by-products by ionizing radiation were investigated. The SF6 concentration was decreased as the ionizing radiation intensity increased. When the initial concentration of SF6 increased, the removal efficiency of SF6 was decreased. As a result, the ionizing radiation intensity and initial concentration were the influencing factor in the treatment process. The deposited particles and aerosol particles on effluent pipeline and HEPA filters were characterized by scanning electron microscopy (SEM) with the energy dispersion spectrum analysis (EDS), attenuated total reflectance/Fourier transform infrared spectroscopy (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS). The amount of aerosol particles in the HEPA filter was influenced by the ionizing radiation intensity. The detected species in the HEPA filter are S-S, SF5, SOF2, SF4, SO2F2, S=0 and SOF4 by FTIR-ATR. This means that the SFx compounds formed by ionizing irradiation still existed. When we compared with results of removal characteristics using plasma, the input energy of ionizing radiation process was 3-37 times higher than that of plasma. However, the required energy of ionizing radiation process for 1 g of SF6 removal was 16-160 times lower than the other processes. It is evident that the ionizing radiation process was more efficient process than that of plasma. (C) 2017 Elsevier Ltd. All rights reserved.