Fe-ZSM-5@SiO2的制备
毕业论文关键字 核壳分子筛 Fe-ZSM-5分子筛 ZSM-5 水热法
Title Syntheses of Fe-ZSM-5@SiO2 Core-Shell Zeolite .
Abstract Fe-ZSM-5 zeolite with different crystal sizes were synthesized using hydrothermal method．The effects of dosage of H2O ,alkalinity and crystallization time on the crystallinity were examined．The samples were characterized by XRD and SEM．The results indicated that the high relative crystallinity of Fe-ZSM-5 zeolite can only be synthesized with the high alkalinity，the less amount of H2O．Fe-ZSM-5@silicalite core-shell composite zeolite were synthesized by different methods．First,The obtained nano Fe-ZSM-5 zeolite was used as a core material，then its surface was pretreated with polydimethyldiallylammonium chloride(PDDA)，and finally secondary crystallization in the silicalite crystallization system . secondly, the core-shell zeolite was directly synthesized with secondary growth in crystallization system.The products were characterized by X-ray diffraction(XRD)，scanning electron microscopy (SEM)，transmission electron microscopy(TEM)，IR and denitrification activity test.The results demonstrated that the Fe-ZSM-5@ silicalite core-shell composite zeolite was synthesized．
Keywords core-shell zeolite Fe-ZSM-5 zeolite ZSM-5 hydrothermal method
目次
1引言1
1.1分子筛的发展..1
1.2ZSM-5分子筛1
1.3纳米级ZSM-5分子筛的合成.2
1.4核壳材料.3
1.5分子筛核壳材料.5
1.6本课题研究内容与意义.7
2实验部分.9
2.1主要试剂与仪器.9
2.2实验步骤..10
2.3表征..11
2.4Fe-ZSM-5@SiO2核壳结构分子筛的脱硝活性测试12
3结果与讨论.12
3.1Fe-ZSM-5分子筛样品的表征分析12
3.2Fe-ZSM-5@SiO2核壳结构的性能分析..20
结论..25
致谢..26
参考文献27
1 引言 1.1 分子筛的发展 分子筛是结晶态的硅酸盐或硅铝酸盐，由硅氧四面体或铝氧四面体通过氧桥键相连而形成分子尺寸大小(通常为 0.3～2.0 nm)的孔道和空腔体系[1]。分子筛具有高的比表面积、规整的微孔结构、可调的骨架结构以及可控的化学性能等特点，被广泛的应用于催化、离子交换和分离等领域[2]。1972 年，美国Mobile公司合成出 ZSM-5 分子[3]。1977 年 Flanigen 等人不加铝源，合成了不含铝的全硅沸石，即“Silicalite” [4]。随着分子筛合成的深入，可将13 种元素如Li，B，Mg，Si，Fe，Ga，Zn等主族金属和过渡金属及非金属元素引入骨架，取代铝或硅。因此根据骨架元素，可将分子筛分为六类：AlPO4-n，SAPO-n，MeAPO-n与 MeASO-n（Me=Fe，Mg，Mn，Zn，Co 等），ElAPO-n 与 ElAPSO-n（El=Ba,Ga，Ge，Li 等）[4]。1988 年，Davis 等成功合成出第一个有十八元环的圆形孔口的磷酸铝VPI-5 (1.27nm×l.27nm) [5]。 1992 年，Mobil公司以表面活性剂为模板剂， 合成了介孔M41S[6]，包括 MCM-41、MCM-48和 MCM-50等介孔材料。