球状活性炭担载MnO_x-CeO_2和尿素的低温无氨脱硝行为研究
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摘要
以MnO_x-CeO_2为活性组分、以尿素为还原剂,制备了球形活性炭(SAC)担载MnO_x-CeO_2和尿素的复合催化剂,利用扫描式电子显微镜-能谱仪(SEM-EDS)、X射线衍射(XRD)和低温N_2吸附-脱附等对催化剂的物理化学结构进行了表征,考察了该催化剂在低温(30-90℃)和没有氨气情况下对NO的选择性催化还原(SCR)性能。结果表明,在30-50℃的反应温度下,炭载体的微孔孔容仍是NO吸附与氧化的主要活性位点;而在70-90℃的反应温度下,锰铈金属氧化物成为NO吸附与氧化的主要活性位点,从而提高了催化剂的SCR反应活性。当反应温度为90℃、空速为6000 h~(-1)、NO和O_2浓度分别为0.05%和20%时,担载8%Mn(锰铈物质的量比为1∶1)和10%尿素的催化剂的NO_x稳态脱除率可达85.6%,实现了在低温、无氨状况下的高效脱硝。
A complex catalyst was prepared by loading MnO_x-CeO_2 and urea on spherical activated carbon( SAC) for the selective catalytic reduction( SCR) of NO at lowtemperature( 30-90 ℃) in the absence of ammonia. The complex catalyst was characterized by scanning electron microscopy-energy dispersive spectrum( SEM-EDS),X-ray diffraction( XRD),and N+2 sorption. The results showthat at 30-50 ℃,the micropores of SAC acts as the main active sites for NO adsorption and reaction,whereas at 70-90 ℃,MnO_x-CeO_2 turns to be the main active sites for NO adsorption and reaction; the urea-SCR activity is enhanced by MnO_x-CeO_2 in a wide temperature range. Over the complex catalyst loaded with 8% Mn( the mole ratio of Mn to Ce is 1) and 10%urea,the steady conversion of NO_x reaches 85.6% in the absence of ammonia,under the conditions of 90 ℃,0.05% NO,20% O_2 and a space velocity of 6000 h~(-1).
A complex catalyst was prepared by loading MnO_x-CeO_2 and urea on spherical activated carbon( SAC) for the selective catalytic reduction( SCR) of NO at lowtemperature( 30-90 ℃) in the absence of ammonia. The complex catalyst was characterized by scanning electron microscopy-energy dispersive spectrum( SEM-EDS),X-ray diffraction( XRD),and N+2 sorption. The results showthat at 30-50 ℃,the micropores of SAC acts as the main active sites for NO adsorption and reaction,whereas at 70-90 ℃,MnO_x-CeO_2 turns to be the main active sites for NO adsorption and reaction; the urea-SCR activity is enhanced by MnO_x-CeO_2 in a wide temperature range. Over the complex catalyst loaded with 8% Mn( the mole ratio of Mn to Ce is 1) and 10%urea,the steady conversion of NO_x reaches 85.6% in the absence of ammonia,under the conditions of 90 ℃,0.05% NO,20% O_2 and a space velocity of 6000 h~(-1).
引文
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[14]LIU X J,LIANG X Y,LIU C J,ZHAN L,QIAO W M,LING L C.Pitch spheres stabilized by HNO3oxidation and their carbonization behavior[J].New Carbon M ater,2010,25(1):29-34.
[15]黄增斌,李翠清,王振,徐胜美,冯凌波,王虹,宋永吉,张伟.不同分子筛负载锰铈催化剂的低温NH3-SCR脱硝性能[J].燃料化学学报,2016,44(11):1388-1393.(HUANG Zeng-bin,LI Cui-qing,WANG Zhen,XU Sheng-mei,FENG Ling-bo,WANG Hong,SONG Yong-ji,ZHANG Wei.Performance of M n-Ce catalysts supported on different zeolites in the NH3-SCR of NOx[J].J Fuel Chem Technol,2016,44(11):1388-1393.)
[16]闫东杰,玉亚,黄学敏,刘树军,刘颖慧.SO2对Mn-Ce/Ti O2低温SCR催化剂的毒化作用研究[J].燃料化学学报,2016,44(2):232-238.(YAN Dong-jie,YU Ya,HUANG Xue-min,LIU Shu-jun,LIU Ying-hui.Poisoning effect of SO2on M n-Ce/Ti O2catalysts for NO reduction by NH3at low temperature[J].J Fuel Chem Technol,2016,44(2):232-238.)
[17]张华伟,陈江艳,赵可,牛庆欣,王力.Mn/Ce掺杂改性半焦对模拟煤气中单质汞的脱除性能研究[J].燃料化学学报,2016,44(4):394-400.(ZHANG Hua-wei,CHEN Jiang-yan,ZHAO Ke,NIU Qing-xin,WANG Li.Removal of vapor-phase elemental mercury from simulated syngas using semi-coke modified by M n/Cedoing[J].J Fuel Chem Technol,2016,44(4):394-400.)
[18]杨晓燕,沈伯雄,马宏卿,刘亭,左琛.前驱物对Mn-Ce/Ti-PILC低温SCR脱硝的影响[J].燃料化学学报,2012,40(1):119-123.(YANG Xiao-yan,SHEN Bo-xiong,MA Hong-qing,LIU Ting,ZUO Chen.Study on the effect of Mn-Ce/Ti-PILC on low temperature SCR activity prepared w ith different precursors[J].J Fuel Chem Technol,2012,40(1):119-123.)
[19]WANG J T,WANG M,LI W C,QIAO W M,LONG D H,LING L C.Application of polyethylenimine-impregnated solid adsorbents for direct capture of low-concentration CO2[J].AICh E J,2015,61(3):972-980.
[2]ZHANG X,LI X G,WU J S,YANG R C,ZHANG Z H.Selective catalytic reduction of NO by ammonia on V2O5/Ti O2catalyst prepared by sol-gel method[J].Catal Lett,2009,130(1):235-238.
[3]袁从慧,刘华彦,卢晗锋,李玉芳,陈银飞.催化氧化-还原吸收法脱除工业含湿废气中NOx[J].环境工程学报,2008,2(9):1207-1212.(YUAN Cong-hui,LIU Hua-yan,LU Han-feng,LI Yu-fang,CHEN Yin-fei.Catalytic oxidation-reductive absorption process for NOxremoval in humid w aste gas[J].Chin J Environ Eng,2008,2(9):1207-1212.)
[4]SHIRAHAMA N,MOCHIDA I,KORAI Y,CHOI K H,ENJOJI T,SHIMOHARA T,YASUTAKE A.Reaction of NO2in air at room temperature w ith urea supported on pitch based activated carbon fber[J].Appl Catal B:Environ,2004,52(3):173-179.
[5]SHIRAHAMA N,MOCHIDA I,KORAI Y,CHOI K H,ENJOJI T,SHIMOHARA T,YASUTAKE A.Reaction of NO with urea supported on activated carbons[J].Appl Catal B:Environ,2005,57(4):237-245.
[6]WANG Z,WANG Y L,LONG D H,MOCHIDA I,QIAO W M,ZHAN L,LIU X J,YOON S H,LING L C.Kinetics and mechanism study of low-temperature selective catalytic reduction of NO w ith urea supported on pitch-based spherical activated carbon[J].Ind Eng Chem Res,2011,50(10):6017-6027.
[7]WANG Z,WANG Y L,WANG D J,CHEN Q J,QIAO W M,ZHAN L,LING L C.Low-temperature selective catalytic reduction of NO w ith urea supported on pitch-based spherical activated carbon[J].Ind Eng Chem Res,2010,49(14):6317-6322.
[8]ZHANG W J,RABIEI S,BAGREEV A,ZHUANG M S,RASOULI F.Study of NO adsorption on activated carbons[J].Appl Catal B:Environ,2008,83(1/2):63-67.
[9]MIYAWAKI J,SHIMOHARA T,SHIMOHARA N,YASUTAKE A,YOSHIKAWA M,MOCHIDA I,YOON S H.Removal of NOxfrom air through cooperation of the Ti O2photocatalyst and urea on activated carbon fiber at room temperature[J].Appl Catal B:Environ,2011,110:273-278.
[10]LU P,ZENG Z,LI C T,ZENG G M,GUO J,JIANG X,ZHAI Y B,FAN X P.Room temperature removal of NO by activated carbon fibres loaded w ith urea and La2O3[J].Environ Technol,2012,33(11):1029-1036.
[11]ZENG Z,LU P,LI C T,ZENG G M,JIANG X,ZHAI Y B,FAN X P.Selective catalytic reduction(SCR)of NO by urea loaded on activated carbon fiber(ACF)and Ce O2/ACF at 30℃:The SCR mechanism[J].Environ Technol,2012,33(11):1331-1337.
[12]JIANG X,LU P,LI C T,ZENG Z,ZENG G M,HU L P,MAI L,LI Z.Experimental study on a room temperature urea-SCR of NO over activated carbon fibre-supported Ce O2-Cu O[J].Environ Technol,2013,34(5):591-598.
[13]崔华飞,李彩亭,路培,彭敦亮,郭静,陈玲.ACF负载金属氧化物及尿素低温去除NO[J].环境科学,2010,31(11):2575-2581.(CUI Hua-fei,LI Cai-ting,LU Pei,PENG Dun-liang,GUO Jing,CHEN Ling.Reaction of NO with metal oxides and urea supported on activated carbons at low temperature[J].Environ sci,2010,31(11):2575-2581.)
[14]LIU X J,LIANG X Y,LIU C J,ZHAN L,QIAO W M,LING L C.Pitch spheres stabilized by HNO3oxidation and their carbonization behavior[J].New Carbon M ater,2010,25(1):29-34.
[15]黄增斌,李翠清,王振,徐胜美,冯凌波,王虹,宋永吉,张伟.不同分子筛负载锰铈催化剂的低温NH3-SCR脱硝性能[J].燃料化学学报,2016,44(11):1388-1393.(HUANG Zeng-bin,LI Cui-qing,WANG Zhen,XU Sheng-mei,FENG Ling-bo,WANG Hong,SONG Yong-ji,ZHANG Wei.Performance of M n-Ce catalysts supported on different zeolites in the NH3-SCR of NOx[J].J Fuel Chem Technol,2016,44(11):1388-1393.)
[16]闫东杰,玉亚,黄学敏,刘树军,刘颖慧.SO2对Mn-Ce/Ti O2低温SCR催化剂的毒化作用研究[J].燃料化学学报,2016,44(2):232-238.(YAN Dong-jie,YU Ya,HUANG Xue-min,LIU Shu-jun,LIU Ying-hui.Poisoning effect of SO2on M n-Ce/Ti O2catalysts for NO reduction by NH3at low temperature[J].J Fuel Chem Technol,2016,44(2):232-238.)
[17]张华伟,陈江艳,赵可,牛庆欣,王力.Mn/Ce掺杂改性半焦对模拟煤气中单质汞的脱除性能研究[J].燃料化学学报,2016,44(4):394-400.(ZHANG Hua-wei,CHEN Jiang-yan,ZHAO Ke,NIU Qing-xin,WANG Li.Removal of vapor-phase elemental mercury from simulated syngas using semi-coke modified by M n/Cedoing[J].J Fuel Chem Technol,2016,44(4):394-400.)
[18]杨晓燕,沈伯雄,马宏卿,刘亭,左琛.前驱物对Mn-Ce/Ti-PILC低温SCR脱硝的影响[J].燃料化学学报,2012,40(1):119-123.(YANG Xiao-yan,SHEN Bo-xiong,MA Hong-qing,LIU Ting,ZUO Chen.Study on the effect of Mn-Ce/Ti-PILC on low temperature SCR activity prepared w ith different precursors[J].J Fuel Chem Technol,2012,40(1):119-123.)
[19]WANG J T,WANG M,LI W C,QIAO W M,LONG D H,LING L C.Application of polyethylenimine-impregnated solid adsorbents for direct capture of low-concentration CO2[J].AICh E J,2015,61(3):972-980.
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