Mn/Zr改性稀土尾矿催化剂NH_(3)-SCR脱硝机理分析  

A Study of Mn/Zr modification for NH_(3)-SCR denitration mechanism of rare earth tailings

作　　者：焦坤灵[1,2] 焦晓云 刘佳杰 李娜 侯丽敏[1] 武文斐 JIAO Kun-ling;JIAO Xiao-yun;LIU Jia-jie;LI Na;HOU Li-min;WU Wen-fei(School of Energy and Environment,Inner Mongolia University of Science and Technology,Baotou 014010,China;Inner Mongolia Autonomous Region Key Laboratory of Efficient and Clean Combustion,Baotou 014010,China)

机构地区：[1]内蒙古科技大学能源与环境学院,内蒙古包头014010 [2]内蒙古自治区高效洁净燃烧重点实验室,内蒙古包头014010

出　　处：《中国环境科学》2023年第11期5655-5662,共8页China Environmental Science

基　　金：内蒙古自治区自然科学基金重大项目(2019ZD13);内蒙古自治区高校基本科研项目(2022098)。

摘　　要：采用溶胶凝胶法制备了Mn、Mn/Zr负载稀土尾矿的NH_(3)-SCR催化剂,通过催化剂活性评价系统,结合H_(2)-TPR、NH_(3)-TPD、XRD和DRIFT研究了催化剂脱硝过程和反应机理.结果表明:Mn、Mn/Zr改性稀土尾矿催化剂的脱硝活性显著增强,在200℃时6%Mn1%Zr/稀土尾矿催化剂脱硝活性可达96%.改性后催化剂表面氧空位、B酸性位点及吸附物种数量明显增加,催化剂还原峰面积增大,其氧化还原性能的提升是活性提高的主要原因.催化剂B酸位NH_(4)^(+)与气态NO_(2)的反应遵循E-R机理,NH_(4)^(+)与单齿、双齿硝酸盐物种的反应遵循L-H机理.Mn and Mn/Zr modified rare earth tailings-based NH_(3)-SCR catalysts were prepared using the sol-gel method.The catalysts were characterized using a catalyst activity evaluation system,along with H_(2)-TPR,NH_(3)-TPD,XRD,and DRIFT techniques,to investigate the denitration process and reaction mechanism.The results showed that the denitration activity of the Mn and Mn/Zr modified rare earth tailings catalysts was significantly enhanced,with a denitration activity of 96%achieved at 200°C for the 6%Mn1%Zr/rare earth tailings catalyst.The modified catalysts exhibited increased oxygen vacancies and acidic sites on the surface,as well as a higher adsorption capacity.The increase in reducible surface area of the catalysts contributed to the improvement of their redox performances.The reaction between NH_(4)^(+)and gaseous NO_(2) on the acidic sites of the catalysts followed the E-R mechanism,while the reactions between NH_(4)^(+)and monodentate and bidentate nitrate species followed the L-H mechanism.

关 键 词：稀土尾矿 Mn、Zr改性 催化剂 NH_(3)-SCR 脱硝机理 

分 类 号：X511[环境科学与工程—环境工程]