三维有序大孔结构脱硝催化剂制备及其抗重金属中毒机理  

Heavy Metal Poisoning Tolerance of Three-Dimensional Ordered Macroporous Denitration Catalyst

作　　者：谭晨晨 韩宇轩 吴鹏 沈凯 庄柯 许芸 胡亚琴 张亚平 TAN Chenchen;HAN Yuxuan;WU Peng;SHEN Kai;ZHUANG Ke;XU Yun;HU Yaqin;ZHANG Yaping(Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education,School of Energy and Environment,Southeast University,Nanjing 210096,China;China Energy Science and Technology Research Institute Co.,Ltd.,Nanjing 210023,China)

机构地区：[1]东南大学能源与环境学院,能源热转换及其过程测控教育部重点实验室,南京210096 [2]国家能源集团科学技术研究院有限公司,南京210023

出　　处：《硅酸盐学报》2024年第5期1608-1620,共13页Journal of The Chinese Ceramic Society

基　　金：国家重点研发计划(2021YB3500604)。

摘　　要：Cd、Pb、Zn等重金属广泛存在于工业废气中,会降低脱硝催化剂的活性。采用聚甲基丙烯酸甲酯(PMMA)模板制备得到具有三维有序大孔结构(3DOM)的Ce0.2Mn0.2/3DOMTiO_(2)(Fresh-CMT-3DOM),作为对比,制备普通结构TiO_(2)载体负载Ce-Mn得到Ce0.2Mn0.2/3DOM(Fresh-CMT)催化剂。活性测试结果表明:相较于Fresh-CMT,Fresh-CMT-3DOM催化剂在100~300℃时的NO转化率超过85%,且在100~150℃低温下具有更高的脱硝活性。引入Cd、Pb、Zn后,Fresh-CMT-3DOM催化剂仍保持较高活性,在175~300℃时的NO转化率均超过85%;而Fresh-CMT催化剂活性明显下降,其中Cd、Pb中毒后催化剂的NO最高转化率分别不足85%、100%。结果表明:相较于Fresh-CMT催化剂,Fresh-CMT-3DOM具有优异的Mn^(4+)/Mn^(3+)/Mn^(2+)及Ce^(4+)/Ce^(3+)氧化还原循环、更高的氧化还原能力及更多的酸性位点,从而促进了Fresh-CMT-3DOM催化剂的低温脱硝活性及抗重金属性能。Introduction Ammonia selective catalytic reduction of NOx with NH3(NH3-SCR)is an effective technology for NOx removal.As a catalyst,V2O5-WO3(MoO3)/TiO_(2) has a high denitrification activity,but suffers from the problems of poor low-temperature activity,high V-toxicity,and susceptibility to heavy metal toxicity at 300-400℃.Heavy metals such as Cd,Pb,Zn,etc.widely present in the flue gas of solid waste incineration and coal-fired power plants.The toxic effects on catalysts are manifested via covering the active sites on the catalyst surface,reducing the redox properties,acidifying the surface and chemically adsorbing oxygen,leading to severe catalyst deactivation.CeO2 as an effective catalyst has a higher oxygen release/storage capacity,which is characterized by a higher oxygen release/storage capacity,compared to the conventional catalysts.CeO2 is used as a main active component in the preparation of rare-earth-based denitrification catalysts due to its high oxygen release/storage capacity.Manganese oxide(i.e.,MnOx)exhibits a good low-temperature catalytic activity,which is often used as a modified component to improve the low-temperature denitrification activity of catalysts.TiO_(2) interacts with the active component and has a higher thermal stability and a sulphur resistance.However,Ce-Mn/Ti catalysts are susceptible to poisoning by toxic substances in the flue gas,and there are more studies on the poisoning of Ce-Mn/Ti catalysts by SO2,H_(2)O,etc..However,a few studies on the poisoning of Ce-Mn/Ti catalysts by heavy metals are reported.Catalysts with three-dimensional ordered macroporous structures have superior redox properties,sufficient chemisorbed oxygen and suitable acid sites to promote its NH3-SCR denitrification reaction.In this paper,Ce-Mn/Ti catalysts with three-dimensional ordered macro-porous structures were thus prepared to increase the redox properties and acidic sites and promote the denitrification activity.Methods 17 m L of tetrabutyl titanate was added drop by drop into 30 m L of anhydrous

关 键 词：三维有序大孔 催化剂 低温氨选择性催化还原脱硝 抗重金属中毒 

分 类 号：X701.7[环境科学与工程—环境工程]