摘要
以四乙基氢氧化铵为模板剂,研究了低模硅比条件下β沸石的合成规律.发现晶种和模板剂之间存在明显的协同导向作用.但碱源对晶种和模板剂的导向作用以及β沸石产物有明显影响.以NaOH为碱源时,晶种的作用主要是缩短晶化诱导期,而模板剂的作用主要是提高晶体生长速率.以氨水为碱源时,晶种和模板剂对缩短诱导期和提高晶体生长速率都有贡献.总的来说,以NaOH为碱源时凝胶的晶化速率较快.但是β沸石产物的硅铝比很低,且晶粒度较大,团聚体比较紧密.相比之下,以氨水为碱源有利于提高β沸石的硅铝比.同时,所合成的β沸石晶粒度小,外表面积大,团聚体中介孔较多.
The synthesis of zeolite β in the condition of low TEAOH/SiO2 ratio was investigated. Results show that the synergistic effect existed between seed and template in terms of structure-directing synthesis. However, signifi- cant influence of alkali source on the effects of template and seed, and the property of zeolite β products was ob- served. When NaOH was used as alkali source, the structure-directing effect of seed was mainly reflected by short- ening the induction period while that of template was mainly reflected by improving the growth rate of crystals. However, when ammonia solution was used as alkali source, seed and template were found all favoring the nuclea- tion and crystal growth. Although NaOH-containing gel showed faster crystallization rate, it produced zeolite β with lower SiO2/Al2O3 ratio and dense aggregates which were composed of larger crystals. In contrast, the ammonia so- lution containing gel could produce zeoliteβ with much higher SIO2/Al2O3 ratio and mesopore-enriched aggregates which were composed of smaller crystals.
出处
《分子催化》
EI
CAS
CSCD
北大核心
2013年第5期429-438,共10页
Journal of Molecular Catalysis(China)
关键词
四乙基氢氧化铵
低模硅比
Β沸石
氨水
硅铝比
tetraethylammonium hydroxide
low TEAOH/SiO2 ratio
zeolite β
ammonia solution
SiO2/Al2O3 ratio
