共查询到18条相似文献,搜索用时 222 毫秒
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沸石/炭分子筛复合膜具有较优良的气体分离效果,是一种非常有发展潜力的膜材料。本研究分别用纳米Beta分子筛和Beta沸石纳米团聚体合成了Beta沸石/炭复合膜,结果表明,Beta沸石纳米团聚体所制备的复合膜的气体分离性能优于纳米Beta分子筛所制备的复合膜。 相似文献
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沸石分子筛是一种具有规则孔道结构的硅铝酸盐晶体,在气体吸附分离、工业催化、重金属离子污染治理等领域被广泛应用。传统沸石分子筛的水热合成常以含硅、铝的化工产品以及有机模板剂为原料,不仅价格昂贵,且污染环境。因此,开展以天然黏土为原料绿色合成沸石分子筛的相关研究,将廉价的天然黏土资源转化成高附加值的化工产品,具有重要的研究意义与经济效益。从天然黏土活化工艺、黏土基沸石合成工艺技术及相关机理等方面介绍了黏土基沸石分子筛的研究进展,重点综述了黏土基沸石分子筛作为工业固体酸催化剂、气体吸附分离反应器及重金属吸附剂的应用,并对黏土基沸石分子筛的未来发展趋势进行了展望。 相似文献
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合成了纳米Beta沸石,并采用X射线衍射(XRD)、透射电镜(TEM)、比表面(BET)、程序升温脱附(NH3-TPD)以及吡啶-红外光谱(Py-IR)等方法对其结构和酸性进行了表征。比较了纳米Beta和常规大晶粒Beta沸石的催化性能,对纳米Beta沸石催化烷基化的关键参数进行了优化。结果表明:在硅铝物质的量比为25~30时,所合成的纳米Beta沸石具有较高的结晶度,晶粒尺寸在20 nm左右。同常规Beta沸石相比,纳米Beta沸石具有更大的BET比表面积和孔容,其比表面积可达600 m2/g,总孔容达0.42 cm3/g,介孔和大孔贡献超过50%。纳米Beta沸石具有较高的总酸量和B酸含量。作为苯和丙烯的烷基化催化剂,纳米Beta沸石具有更好的反应稳定性和选择性。在苯烯比3.0,反应温度150~160℃的条件下,异丙苯选择性可达89%,杂质正丙苯含量可降到极低水平。在工业试验中,纳米Beta沸石也表现出良好的综合性能,催化剂的稳定性和选择性优于同类Beta沸石催化剂。 相似文献
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采用纳米组装法,在酸性条件下,以Beta沸石微晶为原料,P123和正丁醇为介孔导向剂,合成出Beta-KIT-6介微孔复合材料。分析了合成过程中Beta-KIT-6介孔有序度不同的原因。探索了正丁醇用量、HCl浓度、Beta沸石微晶质量分数对介微孔复合材料Beta-KIT-6介孔有序度的影响。结果表明:当正丁醇和TEOS摩尔比为1.5,正丁醇和P123质量比为100,HCl浓度为0.75 mol/L,Beta/P123质量比为88时,所合成的介微孔复合材料具有较好的介孔有序度。 相似文献
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Weimin Zhang Bo Qin Wenxi Li Kaige Hou Yanze Du Jinghong Ma Ruifeng Li 《化学工程与技术》2020,43(11):2224-2232
A hierarchical Beta zeolite has been successfully mass-prepared hydrothermally and dynamically in a pilot-scale autoclave by an economical and simple process with low-cost raw materials. The characterization results indicated that the pilot-scale hierarchical Beta zeolite has the same textural, structural, and acidic properties like the bench-scale sample. Moreover, the catalyst composed of the pilot-scale hierarchical H-Beta zeolite showed higher activity and selectivity to the middle distillate than that containing microporous Beta zeolite in catalytic hydrocracking of vacuum gas oil (VGO) evaluated by an industrial pilot installation in running of 3000 h, due to the increased accessibility and the reduction of diffusion constraint of large molecules to acid sites in the Beta zeolite framework. 相似文献
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Qian MIAO Zhihui ZHOU Jianhua YANG Jinming LU Shiwei YAN Jinqu WANG 《Frontiers of Chemical Engineering in China》2009,3(1):8-11
In this work, zeolite NaA was successfully synthesized by a hydrothermal method using kaolin as a combined source for silica
and alumina. Zeolite NaA with high static water adsorption was synthesized from the low-cost raw material, kaolin, and the
reaction parameters were optimized. Metakaolin was obtained by calcining kaolin at temperatures ranged from 953 K to 1173
K. The synthesis mixture was pre-crystallized at 343 K and crystallized at 373 K successively. Zeolite NaA was obtained, which
was confirmed by SEM, XRD and the water adsorption analysis. The optimized metakaolinization temperature was found at 973
K. The influence of Na2O/SiO2 molar ratio, pre-crystallization time and seed on the crystallization of NaA zeolite was investigated. A thorough mixing
of metakaolin and NaOH solution was favourable for the nucleation/crystallization rate. The obtained NaA zeolite under the
optimized conditions shows excellent crystallinity and static water adsorption of 28.0 wt-%, which was higher than 25.9 wt-%
of the commercial NaA zeolite. Kaolin was suggested to be a feasible and economical raw material for the practical industrial
applications for NaA zeolite. 相似文献
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通过水热合成法制备4A沸石分子筛,在4A沸石分子筛上制备了金属有机骨架(MIL-53)/4A沸石复合材料,研究了原材料配比、晶化时间和晶化温度对复合材料结构的影响,得到了制备复合材料结构的最佳实验条件:4A与对苯二甲酸摩尔比例为0.8:1,晶化时间为10 h,晶化温度为443 K.利用X射线衍射(XRD)、扫描电子显微镜(SEM)、傅里叶红外光谱(FTIR)、氮气吸附对该复合材料进行表征,并对该材料吸附水蒸气性能进行了测试.结果表明该复合材料具有微孔的孔道结构,并具有较好的亲水性. 相似文献
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A novel method for the modification of carbon membranes was developed by zeolite growth on the surface of porous carbon tubes using a hydrothermal synthesis method and carbon-zeolite composite membranes were successfully obtained. Zeolite seeds for the zeolite growth were introduced to the inner surface of the tubes by using a slip-casting technique in 1 wt.% seed ethanol solution and continuous and highly intergrown zeolite layers on the seeded tubes were formed by subsequent hydrothermal synthesis. Different types of zeolite layers can be grown on porous carbon tubes by using different types of zeolite seeds. Without zeolite seeds, a zeolite layer could not be formed on the carbon surface. SEM, XRD and pure gas permeation characterization indicates that the carbon-zeolite membranes are continuous and defect-free. 相似文献
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BETA zeolite nanowire synthesis under non-hydrothermal conditions using carbon nanotubes as template
The properties of carbon nanotubes, used as a nanometric template and as a reactor for the synthesis of BETA zeolite, have been investigated. The confinement effect of the carbon nanotubes, induced by the high aspect ratio of the tubes could be effectively used for the synthesis of one-dimensional nanowire zeolitic materials under non-hydrothermal macroscopic conditions. Zeolite material is easily recovered by combustion of the nanotubes. The average sizes of the zeolite particles are about 20 nm. The BETA zeolite was successfully used as a catalyst for benzoylation of anisol. The zeolite catalyst exhibits a high activity compared to a commercial BETA, essentially due to its high external surface area. 相似文献
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