摘要
以粉煤灰为原料合成分子筛不仅可以实现粉煤灰的高附加值利用,还可促进商用高硅分子筛的绿色低成本合成.但是粉煤灰基分子筛的催化性能和水热稳定性尚有待提高.本文以粉煤灰的活化产物方沸石(ANA)为原料,通过转晶反应和离子交换制备了Cu-SSZ-13分子筛,通过外加晶种和调控前驱体pH值实现分子筛的纳米化和Al落位调控.详细研究了其模拟柴油车尾气选择性催化还原氮氧化物性能和水热稳定性.当溶液pH值为13.5,晶种添加量为0.1%时,合成的Cu-SSZ-13分子筛具有最佳的脱硝性能和水热稳定性,该样品在220℃时NO转换率达到100%,并维持到550℃,N_(2)O生成量小于0.002%.老化处理后,晶种添加量为0.1%的样品的脱硝性能衰减幅度最小,在200℃时NO转化率达到80%,并维持到500℃,N_(2)O生成量小于0.0025%.添加晶种可将分子筛晶粒尺寸从1μm降至150 nm,且相比于其他晶种含量和pH值制备的样品,具有更有序的骨架结构和成对Al,[Z_(2)Cu^(Ⅱ)]物种含量更高,使其水热稳定性更加优异.本文不仅开辟了一种以工业固废原料合成具有优异脱硝和水热稳定性的高硅SSZ-13的方法,并为合成纳米尺度分子筛和调控Al落位提供了新策略.
The development of synthesis methods to make zeolite using the fly ash from coal combustion will not only revalorize the coal combustion waste but also lower the cost of production of commercial zeolites.The key to making zeolite from coal combustion fly ash is to ensure hydrothermal stability for catalyst support use.In this paper,we synthesized zeolite Cu-SSZ-13 from coal fly ash-derived analcime via interzeolite transformation and ion exchange.The Al placement was adjusted by manipulating the pH value of the precursor and varying the amount of SSZ-13 seeding.Thus,nanoscale zeolite Cu-SSZ-13 was synthesized and tested by the removal of NOx from a stimulated exhaust of diesel engines.The experiments showed that the Cu-SSZ-13 made from the precursor solution of pH 13.5 and seeding of 0.1% had the highest NO conversion,lowest N_(2)O yield,and best hydrothermal stability.The NO conversion rate reached 100% at 220~550℃.The N_(2)O yield was below 20×10^(-6).After hydrothermal aging treatment,the NO conversion was still maintained at over 80%at 200~500℃ and the N2O yield was below 25×10^(-6).Characterization showed that adding seed can reduce the crystal size from over 1μm to 150 nm or below.The sample synthesized under the optimized conditions had a more highly ordered framework,more paired Al atoms in the building rings,and more[Z_(2)Cu^(II)]species,compared with samples made under other conditions.
作者
王兵
廖香
何光耀
任卫国
甘皓天
尹瑞琦
李静
韩丽娜
黄张根
吕鹏
鲍卫仁
常丽萍
王建成
WANG Bing;LIAO Xiang;HE Guangyao;REN Weiguo;GAN Haotian;YIN Ruiqi;LI Jing;HAN Lina;HAUNG Zhanggen;LÜPeng;BAO Weiren;CHANG Liping;WANG Jiancheng(State Key Laboratory of Clean and Efficient Coal Utilization,Taiyuan University of Technology,Taiyuan 030024;Key Laboratory of Coal Science and Technology,Ministry of Education,Taiyuan University of Technology,Taiyuan 030024;Chemical Engineering and Technology,Taiyuan University of Technology,Taiyuan 030024;College of Materials Science and Engineering,Taiyuan University of Technology,Taiyuan 030024;State Key Laboratory of Coal Conversion,Institute of Coal Chemistry,Chinese Academy of Sciences,Taiyuan 030001;State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering,School of Chemistry and Chemical Engineering,Ningxia University,Yinchuan 750021)
出处
《环境科学学报》
CAS
CSCD
北大核心
2023年第8期301-313,共13页
Acta Scientiae Circumstantiae
基金
国家自然科学基金(No.21978195,22206148,51820105006)
煤转化国家重点实验室开放课题(No.J20-21-309)
宁夏大学省部共建煤炭清洁高效利用与绿色化工国家重点实验室开放课题(No.2022-K58)。
关键词
粉煤灰再利用
Cu-SSZ-13分子筛
转晶
水热稳定性
选择性催化还原
revalorization of fly ash from coal combustion
zeolite Cu-SSZ-13
interzeolite transformation
hydrothermal stability
selective catalytic reduction
