Fe添加对Mn/γ-Al_2O_3催化剂低温选择性催化还原NO的性能影响
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摘要
为考察Fe添加量对锰基催化剂低温选择性催化还原(SCR)烟气中NO的性能,采用湿式浸渍法制备以γ-Al_2O_3为载体,以MnOx、FeOx为活性组分的系列催化剂,通过X射线衍射(XRD)、扫描电镜(SEM)、X射线光电子能谱(XPS)分析等手段对其进行表征。结果表明:Fe的引入对提高催化剂的SCR活性具有明显的促进作用。Fe添加量为0.04 mmol/g时制备的Mn(0.8)-Fe(0.04)/γ-Al_2O_3催化剂脱硝效率在150℃条件下即可以达到93.1%。Fe添加量为0.04mmol/g时催化剂中形成的球状结晶β-MnO_2分散最为均匀,最有利于催化反应的进行。比表面积不是影响催化剂SCR活性的决定性因素。Mn(0.8)-Fe(0.04)/γ-Al_2O_3催化剂孔径分布以2～50nm的中孔为主,活性组分也主要负载到较大的中孔中,有利于催化反应的进行。Fe的加入可以提高催化剂的抗硫性能。
In order to investigate the influence of Fe-doped amount on the low temperature selective catalytic reduction(SCR)performance of Mn-based catalysts,a series of catalysts withγ-Al_2O_3 as the support and MnOx,FeOx as the active component were prepared by wet impregnation method.XRD,SEM,XPS and other test methods were used to characterize the properties of the catalysts.It was found that the SCR activity of Mn/γ-Al_2O_3 catalysts was obviously improved after Fe-doped.The results showed that 93.1% NO conversion was obtained by Mn(0.8)-Fe(0.04)/γ-Al_2O_3 catalyst at 150 ℃.When the Fe-doped amount was 0.04 mmol/g,the dispersion of sphericalβ-MnO_2 crystal was most evenly and conducive to the catalytic reaction.The specific surface area was not a decisive factor affecting the SCR activity of the catalysts.The pore size distribution of Mn(0.8)-Fe(0.04)/γ-Al_2O_3 catalyst was dominated by mesopores of 2-50 nm,and the active component was also mainly loaded into the larger mesopores,which was favorable for the catalytic reaction.Moreover,the addition of Fe could improve the sulfur resistance of the catalyst.
In order to investigate the influence of Fe-doped amount on the low temperature selective catalytic reduction(SCR)performance of Mn-based catalysts,a series of catalysts withγ-Al_2O_3 as the support and MnOx,FeOx as the active component were prepared by wet impregnation method.XRD,SEM,XPS and other test methods were used to characterize the properties of the catalysts.It was found that the SCR activity of Mn/γ-Al_2O_3 catalysts was obviously improved after Fe-doped.The results showed that 93.1% NO conversion was obtained by Mn(0.8)-Fe(0.04)/γ-Al_2O_3 catalyst at 150 ℃.When the Fe-doped amount was 0.04 mmol/g,the dispersion of sphericalβ-MnO_2 crystal was most evenly and conducive to the catalytic reaction.The specific surface area was not a decisive factor affecting the SCR activity of the catalysts.The pore size distribution of Mn(0.8)-Fe(0.04)/γ-Al_2O_3 catalyst was dominated by mesopores of 2-50 nm,and the active component was also mainly loaded into the larger mesopores,which was favorable for the catalytic reaction.Moreover,the addition of Fe could improve the sulfur resistance of the catalyst.
引文
[1]徐青,郑章靖,凌长明,等.氮氧化物污染现状和控制措施[J].安徽农业科学,2010,38(29):16388-16391.
[2]LU B H,JIANG Y,CAI L L,et al.Enhanced biological removal of NOxfrom flue gas in a biofilter by Fe(Ⅱ)Cit/Fe(Ⅱ)EDTAabsorption[J].Bioresource Technology,2011,102(17):7707-7712.
[3]赵毅,万敬敏,刘凤,等.Fe(Ⅱ)(DMPS)2用于烟气脱硫脱硝的研究[J].江苏环境科技,2010,18(增刊1):7-9.
[4]李伟,吴成志,马碧瑶,等.半胱氨酸亚铁溶液吸收一氧化氮的研究[J].中国环境科学,2005,25(3):306-309.
[5]吴春华,柏源,李忠华,等.Fe(Ⅱ)EDTA溶液络合吸收燃煤烟气NO性能研究[J].电力科技与环保,2013,29(1):16-18.
[6]LONG R Q,YANG R T,CHANG R.Low temperature selective catalytic reduction(SCR)of NO with NH3over Fe-Mn based catalysts[J].Chemical Communications,2002,5(5):452-453.
[7]THIRUPATHI B,SMIRNIOTIS P G.Nickel-doped Mn/TiO2as an efficient catalyst for the low-temperature SCR of NOwith NH3:catalytic evaluation and characterizations[J].Journal of Catalysis,2012,288(4):74-83.
[8]SULTANA A,SASAKI M,HAMADA H.Influence of support on the activity of Mn supported catalysts for SCR of NO with ammonia[J].Catalysis Today,2012,185(1):284-289.
[9]WAN Y P,ZHAO W R,TANG Y,et al.Ni-Mn bi-metal oxide catalysts for the low temperature SCR removal of NO with NH3[J].Applied Catalysis B:Environmental,2014,148(6):114-122.
[10]孙科,刘伟,王岳军,等.Ce-Mn/TiO2低温SCR脱硝催化剂成型工艺中添加剂的影响实验研究[J].环境污染与防治,2013,35(11):37-41.
[11]王宽岭,王学海,刘忠生.Mn-Fe-Ce/Al2O3/堇青石催化剂低温NH3-SCR脱硝性能研究[J].当代化工,2015(9):2057-2060.
[12]林涛,徐海迪,李伟,等.整体式Mn-Fe/ZrO2-TiO2催化剂的制备及在低温NH3-SCR反应中的性能[J].高等学校化学学报,2009,30(11):2240-2246.
[13]KIM Y J,KWON H J,HEO I,et al.Mn-Fe/ZSM5as a lowtemperature SCR catalyst to remove NOxfrom diesel engine exhaust[J].Applied Catalysis B:Environmental,2012,126(38):9-21.
[14]ZHANG X,JI L Y,ZHANG S C,et al.Synthesis of a novel polyaniline-intercalated layered manganese oxide nanocomposite as electrode material for electrochemical capacitor[J].Journal of Power Sources,2007,173(2):1017-1023.
[15]冯云桑.Co-Ce氧化物对Mn/TiO2系低温脱硝催化剂结构与性能的影响[D].镇江:江苏科技大学,2013.
[2]LU B H,JIANG Y,CAI L L,et al.Enhanced biological removal of NOxfrom flue gas in a biofilter by Fe(Ⅱ)Cit/Fe(Ⅱ)EDTAabsorption[J].Bioresource Technology,2011,102(17):7707-7712.
[3]赵毅,万敬敏,刘凤,等.Fe(Ⅱ)(DMPS)2用于烟气脱硫脱硝的研究[J].江苏环境科技,2010,18(增刊1):7-9.
[4]李伟,吴成志,马碧瑶,等.半胱氨酸亚铁溶液吸收一氧化氮的研究[J].中国环境科学,2005,25(3):306-309.
[5]吴春华,柏源,李忠华,等.Fe(Ⅱ)EDTA溶液络合吸收燃煤烟气NO性能研究[J].电力科技与环保,2013,29(1):16-18.
[6]LONG R Q,YANG R T,CHANG R.Low temperature selective catalytic reduction(SCR)of NO with NH3over Fe-Mn based catalysts[J].Chemical Communications,2002,5(5):452-453.
[7]THIRUPATHI B,SMIRNIOTIS P G.Nickel-doped Mn/TiO2as an efficient catalyst for the low-temperature SCR of NOwith NH3:catalytic evaluation and characterizations[J].Journal of Catalysis,2012,288(4):74-83.
[8]SULTANA A,SASAKI M,HAMADA H.Influence of support on the activity of Mn supported catalysts for SCR of NO with ammonia[J].Catalysis Today,2012,185(1):284-289.
[9]WAN Y P,ZHAO W R,TANG Y,et al.Ni-Mn bi-metal oxide catalysts for the low temperature SCR removal of NO with NH3[J].Applied Catalysis B:Environmental,2014,148(6):114-122.
[10]孙科,刘伟,王岳军,等.Ce-Mn/TiO2低温SCR脱硝催化剂成型工艺中添加剂的影响实验研究[J].环境污染与防治,2013,35(11):37-41.
[11]王宽岭,王学海,刘忠生.Mn-Fe-Ce/Al2O3/堇青石催化剂低温NH3-SCR脱硝性能研究[J].当代化工,2015(9):2057-2060.
[12]林涛,徐海迪,李伟,等.整体式Mn-Fe/ZrO2-TiO2催化剂的制备及在低温NH3-SCR反应中的性能[J].高等学校化学学报,2009,30(11):2240-2246.
[13]KIM Y J,KWON H J,HEO I,et al.Mn-Fe/ZSM5as a lowtemperature SCR catalyst to remove NOxfrom diesel engine exhaust[J].Applied Catalysis B:Environmental,2012,126(38):9-21.
[14]ZHANG X,JI L Y,ZHANG S C,et al.Synthesis of a novel polyaniline-intercalated layered manganese oxide nanocomposite as electrode material for electrochemical capacitor[J].Journal of Power Sources,2007,173(2):1017-1023.
[15]冯云桑.Co-Ce氧化物对Mn/TiO2系低温脱硝催化剂结构与性能的影响[D].镇江:江苏科技大学,2013.