Wet process of elemental mercury removal from flue gas using Ag/AgCl photocatalyst under visible light
XING Wei-bo1, LU Hao1, ZHANG An-chao1, LIU Mu1, LIU Zhi-chao1, HU Song2, XIANG Jun2
1. School of Mechanical and Power Engineering, Henan Polytechnic University, Jiaozuo 454000, China;
2. State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
A series of studies on the performance of Hg0 removal from simulated flue gas were carried out in a wet Hg0 bubbling reactor using a visible-light-responsive Ag/AgCl photocatalyst prepared by a precipitation-photoreduction method. The effects of SO2, NO, and reaction temperature were also investigated in detail. The properties of fresh and used photocatalysts were characterized by N2 adsorption/desorption, scanning electron microscope and energy dispersive X-ray spectroscopy (SEM-EDS), X-ray diffraction (XRD), UV-visible diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR) techniques. The results showed that compared with the Hg0 removal efficiencies of only visible light irradiation and only Ag/AgCl, Hg0 removal efficiency was greatly enhanced when visible light and Ag/AgCl were employed simultaneously. Due to large amounts of reactive species consumption, the presences of SO2 and NO would inhibit the performance of Hg0 removal. The activity of Hg0 removal could be restored to their initial values when SO2 and NO were turned off. The reactive species, such as hydroxyl radicals (·OH), superoxide radicals (·O2-), were produced in the Ag/AgCl solution under visible light. The ·OH, holes (h+), and Cl2, were reactive species responsible for removing Hg0, and in particular the ·O2- played a key role in Hg0 removal.
邢微波, 路好, 张安超, 刘牧, 刘志超, 胡松, 向军. Ag/AgCl可见光催化剂湿法脱除烟气中单质汞研究[J]. 中国环境科学, 2017, 37(2): 503-510.
XING Wei-bo, LU Hao, ZHANG An-chao, LIU Mu, LIU Zhi-chao, HU Song, XIANG Jun. Wet process of elemental mercury removal from flue gas using Ag/AgCl photocatalyst under visible light. CHINA ENVIRONMENTAL SCIENCECE, 2017, 37(2): 503-510.
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