Simultaneous Removal Of Elemental Mercury(Hg~0)and NO By Ti-Al-Ce-nanoparticle Catalyst From Simulated Coal-Fired Flue Gas

China is the largest producer and consumer in the world at present.The coal-fired flue gas is one of the primary sources of air pollutants,in which NOX and Hg0 have received extensive attention as two atmospheric contaminants emitted from coal-fired boilers.NOx emissions can cause photochemical smog,acid rain and other environmental problems,Hg0 is a global pollutant with toxicity,bio-accumulation and volatility,both of them could result in lots of environmental and health risks.Several methods have been investigated in order to control NOx and Hg0 emissions in coal-fired flue gas effectively.Among them,selection catalytic reduction of NO by NH3(NH3-SCR)is the most effective method of controlling NOx emission in the flue gas.Meanwhile,lots of coal-fired power plants have been equipped with SCR system and wet flue gas desulfurization devices(WFGD).Accordingly,simultaneous removal of NOx and Hg0 with an already existing SCR system was proposed,this technology is of great importance for NOx and Hg0 control in coal-fired flue gas.A series of nano-sized TiO2-Al2O3-CeO2 catalysts were synthesized via sol-gel method.The performance of nano-sized TiO2-A12O3-CeO2 catalysts for simultaneous removal of NO and Hg0 was studied in the presence of simulated flue gas.Meanwhile,the effects of Ce loading,reaction temperature,Al2O3 modification and different flue gas components(including H2O,SO2 and O2)on the activity of TiO2-Al2O3-CeO2 catalysts were investigated.The interaction between NH3-SCR and Hg0 removal was also studied.Simultaneously,crucial characterizations including ICP-OES,BET,XRD,SEM,TEM,XPS,H2-TPR and FT-IR of catalysts were conducted to examine the physicochemical properties of catalysts and further reveal the mechanisms of simultaneous removal of NO and Hg0 over TiO2-Al2O3-CeO2 catalysts.The results showed that TiAl10Ce20 nanoparticle with the addition of 10wt%Al2O3 exhibited superior NO removal efficiency(93.41%)and Hg0 removal efficiency(80.54%)in the presence of SCR atmosphere at 300?.The deactivation effects of H2O and SO2 were also reduced by Al2O3 addition.In the presence of SCR atmosphere,the capture of Hg0 was inhibited by the existence of NH3,while the presence of Hg0 had little impact on NO removal.The characterization results showed that the excellent performance of TiAl10Ce20 nanoparticle might result from the stronger redox ability,lower crystallinity and better texture properties with highly dispersed Ce species,which were all attributed to Al2O3 addition.The research also showed that TiA110Ce20 nanoparticle developed in this work was considered to be a promising catalyst for simultaneous removal of NO and Hg0 with favorable prospect for industrial application.