低温无氧锯末炭负载Fe/Fe_3C催化剂的烟气脱硝实验
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摘要
以杨木木屑和硝酸铁为原料,制备低成本多孔负载型炭材料,是通过一个简单的工艺一步完成了炭化、活化以及负载的过程,形成了多孔碳以及纳米零价铁和碳化铁。采用XRD、BET、SEM、工业元素分析等分析手段,对多孔碳上负载的活性组分进行了表征,结果表明:锯末炭上负载的硝酸铁经过热还原被转化为零价铁,700℃时发生固体渗碳现象形成了Fe_3C,Fe_3C在750℃时发生分解。用硝酸铁活化木屑制备的炭材料载体的比表面积和孔容分别为125. 649m~2/g和0. 169cm~3/g,发达的介孔结构为活性组分在多孔碳表面的高度分散提供了条件。该催化剂具有高效的低温无氧脱硝活性,280℃条件下最高脱硝效率可达100%且避免了载体炭损耗,XRD表明零价Fe在催化还原NO的过程中被氧化为Fe_3O_4,导致催化剂活性降低。
The low-cost porous loaded carbon materials were prepared from poplar sawdust and ferric nitrate. Through a simple process step to complete the process of carbonization and activation as well as the load,the formation of the porous carbon nano zero-valent iron and iron carbide,and XRD,BET,SEM analysis,industrial elements such as the load on the way to the porous carbon had been used to characterize the active component,the results show that the load on the sawdust charcoal ferric nitrate reduction after heat into zero-valent iron,solid carburizing phenomenon formed Fe3 C in 700℃,but Fe3 C can decompose instability in 750℃. The specific surface area and pore volume of the porous carbon obtained by activating wood chips with ferric nitrate were 125. 649m2/g and 0. 169cm3/g,respectively. The well-developed mesoporous structure provided conditions for the high dispersion of active components on the surface of porous carbon. The catalyst has the efficient anaerobic denitration activity,low temperature 280℃ under the condition of the highest denitration efficiency can reach 100%and avoid the carrier carbon loss,XRD indicates that zero-valent Fe in the process of catalytic reduction of NO is oxidized to Fe3O4 which reduced the catalytic activity of catalysts.
The low-cost porous loaded carbon materials were prepared from poplar sawdust and ferric nitrate. Through a simple process step to complete the process of carbonization and activation as well as the load,the formation of the porous carbon nano zero-valent iron and iron carbide,and XRD,BET,SEM analysis,industrial elements such as the load on the way to the porous carbon had been used to characterize the active component,the results show that the load on the sawdust charcoal ferric nitrate reduction after heat into zero-valent iron,solid carburizing phenomenon formed Fe3 C in 700℃,but Fe3 C can decompose instability in 750℃. The specific surface area and pore volume of the porous carbon obtained by activating wood chips with ferric nitrate were 125. 649m2/g and 0. 169cm3/g,respectively. The well-developed mesoporous structure provided conditions for the high dispersion of active components on the surface of porous carbon. The catalyst has the efficient anaerobic denitration activity,low temperature 280℃ under the condition of the highest denitration efficiency can reach 100%and avoid the carrier carbon loss,XRD indicates that zero-valent Fe in the process of catalytic reduction of NO is oxidized to Fe3O4 which reduced the catalytic activity of catalysts.
引文
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[2]何昭文,张旺,张荻.功能Fe3C的制备及其性能研究进展[J].材料导报A:综述篇,2012,26(5):21-26.
[3] LLN-GMEZ M. J.,RAYMUNDO-PIERO E.,GARCA-GARCA A.,et al. Catalytic NOx reduction by carbon supporting metals[J]. Applied Catalysis B:Environmental,1999,20(4):267-275.
[4] Jin Sun Cha,et al. The low-temperature SCR of NO over rice straw and sewage sludge derived char[J].Chemical Engineering Journal,2010,156:321-327.
[5] LI Xianchun,DONG Zhen,et al. Catalytic reduction of NO using iron oxide impregnated biomass and lignite char for flue gas treatment[J]. Fuel Processing Technology,2016,148:91-98.
[6]印安冬,邓文义,马璟宸等.污泥热解炭脱除NO特性[J].化工学报,2018,69(6):2655-2663.
[7] Teng H S,Suuberg E M,Chemisorptions of nitricoxide on char(Ⅰ):Reversible nitric-oxide sorption[J]. J. Phys. Chem.,1993,97(2):478-483.
[8] Teng H S,Suuberg E M,Chemisorptions of nitricoxide on char(Ⅱ):Irreversible carbon oxide formation[J]. Ind. Eng. Chem. Res.,1993,32(3):416-423.
[9] S. Ismadji*,Y. Sudaryanto,S. B. Hartono,et al.Activated carbon from char obtained from vacuum pyrolysis of teak sawdust:pore structure development and characterization[J]. Bioresource Technology,2005,96:1364-1369.
[10] U. Jansson,E. Lewin. Sputter deposition of transition-metal carbide films-A critical review from a chemical perspective. Thin Solid Films[J]. 2013,536:1-24.
[11] LLN-GMEZ M. J.,Linares-Solano A.,et al.NO Reduction by Activated Carbons. 7. Some Mechanistic Aspects of Uncatalyzed and Catalyzed Reaction[J]. Energy&Fuels,1996,10,158-168.
[12] LLN-GMEZ M J,LINARES-SOLANO A,RADOVIC L R. NO reduction by activated carbons(2):Catalytic effect of potassium[J]. Energy&Fuels,1995,9(1):97-103.