低温离子浓缩交换Ag/Cu-ZSM-5分子筛催化剂的制备及其脱硝性能的评价
|
摘要
结合固相分散法和液相浸渍法的优点,提出一种耗时短、负载量高、分散性和稳定性好的低温离子浓缩交换法,并将其用于Ag/Cu-ZSM-5分子筛催化剂的制备,即在超声波作用下进行低温离子浓缩交换,然后采用微波马弗炉焙烧,使Ag、Cu离子在分子筛的铝羟基和桥联羟基上进行离子交换,并可使更多的离子交换到活性更高的铝羟基上,从而提升了催化剂的脱硝活性和反应空速。通过对催化剂的表征以及脱硝活性的评价,表明:当硅铝比为38、硝酸银和分子筛质量比为0.453、Ag和Cu摩尔量比值为1时,Ag/Cu-ZSM-5催化剂处理NO的效果最佳。在空速为4000~4500 h~(-1)、NO体积含量为2000 ppm(平衡气为N_2)、O_2体积分数为5%、温度为310~440℃的反应条件下,NO的分解率均在45%以上,在反应温度为390℃时,NO的分解率为78.1%。
Combining the advantages of dispersion method and dipping method,a low temperature ion concentration exchange method to prepare Ag/Cu-ZSM-5 molecular sieve catalyst with short time,high load,good dispersibility and good stability was put forward.Under the action of ultrasound,ion concentration exchange at low temperature and microwave roasting can make aluminum hydroxyl and bridged hydroxyl of molecular sieve happen ion exchange,and more metal ions can be exchanged to aluminum hydroxyl with higher activity,thus increasing the denitrification activity of the catalyst and the reaction space velocity.Through the characterization of the catalyst and the De NOx performance.The results show that the decomposition effect of NO of Ag/Cu-ZSM-5 catalyst is best when the silica and alumina ratio is 38,the quality ratio of silver nitrate and molecular sieve is 0.453,the molar ratio of Ag and Cu is 1.Under the reaction condition that the space velocity is 4000-4500 h~(-1),NO volume content is 2000 ppm(the balance gas is N_2),O_2volume fraction is 5%and the temperature is 310-440℃,the decomposition rate of NO can reach above 45%.And at the reaction temperature is 390℃,the decomposition rate of NO can reach 78.1%.
Combining the advantages of dispersion method and dipping method,a low temperature ion concentration exchange method to prepare Ag/Cu-ZSM-5 molecular sieve catalyst with short time,high load,good dispersibility and good stability was put forward.Under the action of ultrasound,ion concentration exchange at low temperature and microwave roasting can make aluminum hydroxyl and bridged hydroxyl of molecular sieve happen ion exchange,and more metal ions can be exchanged to aluminum hydroxyl with higher activity,thus increasing the denitrification activity of the catalyst and the reaction space velocity.Through the characterization of the catalyst and the De NOx performance.The results show that the decomposition effect of NO of Ag/Cu-ZSM-5 catalyst is best when the silica and alumina ratio is 38,the quality ratio of silver nitrate and molecular sieve is 0.453,the molar ratio of Ag and Cu is 1.Under the reaction condition that the space velocity is 4000-4500 h~(-1),NO volume content is 2000 ppm(the balance gas is N_2),O_2volume fraction is 5%and the temperature is 310-440℃,the decomposition rate of NO can reach above 45%.And at the reaction temperature is 390℃,the decomposition rate of NO can reach 78.1%.
引文
[1]Armor J N.Catalytic removal of nitrogen oxides:where are the opportunities[J].Catalysis Today,1995,26(2):99-105.
[2]Iwamoto M,Hamada H.Removal of nitrogen monoxide from exhaust gases through novel catalytic processes[J].Catalysis Today,1991,10(1):57-71.
[3]Nova I,Ciardelli C,Tronconi E,et al.NH3-NO/NO2SCR for diesel exhausts after treatment:mechanism and modelling of a catalytic converter[J].Topics in Catalysis,2007,42(1-4):43-46.
[4]阳鹏飞,周继承,李德华,等.Au/TS-1选择性催化氧化NO性能研究[J].燃料化学学报,2010,38(1):80-84.
[5]陈建孟,Lance H,陈浚,等.自养型生物过滤器硝化氧化一氧化氮[J].环境科学,2003,24(2):1-6.
[6]张国孟,王战科,张光旭,等.H-ZSM-5分子筛吸附-氧化NOx的研究[J].环境科学学报,2017,37(1):89-94.
[7]陈艳平,程党国,陈丰秋,等.Cu-ZSM-5分子筛催化分解及选择性催化还原NO[J].化学进展,2014,26(Z1):248-258.
[8]陈凯歌,陈若愚,唐喆,等.低温等离子改性对Ce/Ti O2-Al2O3脱硝性能的影响[J].硅酸盐通报,2017,36(10):1001-1625.
[9]关乃佳,单学雷,曾翔,等.Cu-ZSM-5/堇青石整体式催化剂上NO的吸附态及分解反应机理[J].催化学报,2001,22(3):245-249.
[10]Zhang Y,Flytzani-Stephanopoulos M.Hydrothermal stability of cerium modified Cu-ZSM-5 catalyst for nitric oxide decomposition[J].Journal of Catalysis,1996,164(1):131-145.
[11]Moretti G,Dossi C,Fusi A,et al.A comparison between Cu-ZSM-5,Cu-S-1 and Cu-mesoporous-silica-alumna as catalysts for NO decomposition[J].Applied Catalysis B:Environmental,1999,20(1):67-73.
[12]Prvulescu V I,Grange P,Delmon B.NO decomposition over physical mixtures of Cu-ZSM-5 with zeolites or oxides[J].Applied Catalysis B Environmental,2001,33(3):223-237.
[13]姜慧超,王一迪,赵朝成,等.Cu-ZSM-5催化剂直接催化分解NO的试验研究[J].石油炼制与化工,2015,46(3):43-47.
[14]郭锡坤,陈庆生,张俊豪,等.Cu/Al2O3催化剂的改性及其对NO选择性还原的催化性能[J].催化学报,2005,26(12):1104-1108.
[15]曲虹霞,钟秦,邓选英.Ce3+(La3+)改性Cu-ZSM-5催化剂分解NO活性的研究[J].中国环境科学,2006,26(4):395-399.
[16]石川,宋志民,付迎,等.Ni2+改性的Cu-ZSM-5催化分解NO的性能[J].环境科学,2000,21(6):24-27.
[17]万家义,余林,陈豫.Cu-M/ZSM-S(M=Ce,La,Ag)催化剂的表征及其对NO直接分解催化活性的研究[J].化学研究与应用,1999,11(1):11-15.
[18]薛全民,张永春.钴铜改性的ZSM-5对低浓度NO吸附性能的研究[J].环境科学,2004,25(6):63-65.
[19]阳鹏飞,周继承,任文明.微波固相法制备Cu/ZSM-5催化剂及其催化性能[J].南华大学学报,2010,24(3):64-69.
[20]罗羽裳,张天芳,杨凌云,等.微波辐照离子交换法制备Cu-ZSM-5和Cu-ZSM-11[J].离子交换与吸附,2016,32(6):568-576.
[21]刘士豪,刘会轩,张光旭,等.离子交换制备Cu-ZSM-5催化剂的方法[P].中国专利:201711364463.6.
[2]Iwamoto M,Hamada H.Removal of nitrogen monoxide from exhaust gases through novel catalytic processes[J].Catalysis Today,1991,10(1):57-71.
[3]Nova I,Ciardelli C,Tronconi E,et al.NH3-NO/NO2SCR for diesel exhausts after treatment:mechanism and modelling of a catalytic converter[J].Topics in Catalysis,2007,42(1-4):43-46.
[4]阳鹏飞,周继承,李德华,等.Au/TS-1选择性催化氧化NO性能研究[J].燃料化学学报,2010,38(1):80-84.
[5]陈建孟,Lance H,陈浚,等.自养型生物过滤器硝化氧化一氧化氮[J].环境科学,2003,24(2):1-6.
[6]张国孟,王战科,张光旭,等.H-ZSM-5分子筛吸附-氧化NOx的研究[J].环境科学学报,2017,37(1):89-94.
[7]陈艳平,程党国,陈丰秋,等.Cu-ZSM-5分子筛催化分解及选择性催化还原NO[J].化学进展,2014,26(Z1):248-258.
[8]陈凯歌,陈若愚,唐喆,等.低温等离子改性对Ce/Ti O2-Al2O3脱硝性能的影响[J].硅酸盐通报,2017,36(10):1001-1625.
[9]关乃佳,单学雷,曾翔,等.Cu-ZSM-5/堇青石整体式催化剂上NO的吸附态及分解反应机理[J].催化学报,2001,22(3):245-249.
[10]Zhang Y,Flytzani-Stephanopoulos M.Hydrothermal stability of cerium modified Cu-ZSM-5 catalyst for nitric oxide decomposition[J].Journal of Catalysis,1996,164(1):131-145.
[11]Moretti G,Dossi C,Fusi A,et al.A comparison between Cu-ZSM-5,Cu-S-1 and Cu-mesoporous-silica-alumna as catalysts for NO decomposition[J].Applied Catalysis B:Environmental,1999,20(1):67-73.
[12]Prvulescu V I,Grange P,Delmon B.NO decomposition over physical mixtures of Cu-ZSM-5 with zeolites or oxides[J].Applied Catalysis B Environmental,2001,33(3):223-237.
[13]姜慧超,王一迪,赵朝成,等.Cu-ZSM-5催化剂直接催化分解NO的试验研究[J].石油炼制与化工,2015,46(3):43-47.
[14]郭锡坤,陈庆生,张俊豪,等.Cu/Al2O3催化剂的改性及其对NO选择性还原的催化性能[J].催化学报,2005,26(12):1104-1108.
[15]曲虹霞,钟秦,邓选英.Ce3+(La3+)改性Cu-ZSM-5催化剂分解NO活性的研究[J].中国环境科学,2006,26(4):395-399.
[16]石川,宋志民,付迎,等.Ni2+改性的Cu-ZSM-5催化分解NO的性能[J].环境科学,2000,21(6):24-27.
[17]万家义,余林,陈豫.Cu-M/ZSM-S(M=Ce,La,Ag)催化剂的表征及其对NO直接分解催化活性的研究[J].化学研究与应用,1999,11(1):11-15.
[18]薛全民,张永春.钴铜改性的ZSM-5对低浓度NO吸附性能的研究[J].环境科学,2004,25(6):63-65.
[19]阳鹏飞,周继承,任文明.微波固相法制备Cu/ZSM-5催化剂及其催化性能[J].南华大学学报,2010,24(3):64-69.
[20]罗羽裳,张天芳,杨凌云,等.微波辐照离子交换法制备Cu-ZSM-5和Cu-ZSM-11[J].离子交换与吸附,2016,32(6):568-576.
[21]刘士豪,刘会轩,张光旭,等.离子交换制备Cu-ZSM-5催化剂的方法[P].中国专利:201711364463.6.