共查询到20条相似文献,搜索用时 78 毫秒
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真空原位水热合成法快速合成A型分子筛膜 总被引:2,自引:0,他引:2
采用真空原位水热法在管状αAl2O3基膜上快速合成了A型分子筛膜;采用XRD和SEM方法表征了膜的性质;研究了真空度对A型分子筛膜性能的影响。在外加真空作用下,分子筛晶粒可以均匀、快速地迁移到基膜表面形成分子筛膜,从而可以在较短时间里合成均匀、连续的分子筛膜。 相似文献
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MCM-48介孔分子筛的合成研究 总被引:23,自引:0,他引:23
利用水热法合成了MCM-48介孔分子筛,通过IR,TG-DTA,XRD,TEM,N2吸附等方法对产物进行了表征,并系统地研究了晶化温度、晶化时间、凝胶组成等对合成MCM-48介孔分子筛的影响 相似文献
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以δ-氧化铝为基底和铝源, 使用离子热基底自转晶法, 在[EMIm]Br离子液体中合成了AEL磷酸铝分子筛膜. 采用X射线(XRD)和扫描电镜(SEM)等方法对所得的AEL分子筛膜进行了表征, 研究了合成条件对膜的影响. 研究发现在氢氟酸和磷酸离子液体混合溶液中一步反应可以合成c轴高度取向的AEL分子筛膜, 在氢氟酸和磷酸离子液体溶液中分别顺序两步反应可以合成无取向的AEL分子筛膜. 离子热基底自转晶法分子筛膜的形成符合固相转化机理, 氟离子可以促进分子筛膜的生长, 并影响分子筛膜的取向. 相似文献
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等离子体辅助合成分子筛膜及其催化性能的研究 总被引:1,自引:0,他引:1
首次将等离子体技术应用于分子筛膜的制备,研究了以微波等离子体处理基材表面分子筛膜前驱体辅助水热反应合成支撑β型分子筛膜.利用XRD、SEM、XPS、BET、TPD表征了分子筛膜的物相、形貌、孔结构、表面元素组成和表面酸性,并通过甲醇与异丁烯液相反应体系实验考察了分子筛膜的催化性能.结果表明,等离子体处理能有效改善分子筛膜前驱体在基材表面的分散状况,减小了分子筛膜晶体的尺度,使晶体大小均匀,形成的膜致密、牢固.与采用常规方法合成的分子筛膜相比,等离子体辅助合成的分子筛膜对甲醇与异丁烯的反应有更好的催化活件. 相似文献
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钒硅MCM—41沸石分子筛微波合成与表征 总被引:5,自引:0,他引:5
以溴代十六烷基吡啶(CPBr)为模板剂,硅溶胶为硅源,用微波辐射的方法成功地合成出了高结晶度的中孔杂原子VMCM-41分子筛,探讨了微波反应釜压力、微波晶化时间、老化时间等合成因素的影响,确定了合适的配比范围及合成条件。利用XRD、TEM、IR等方法对VMCM-41中孔分子筛的结构作了表征,结果表明钒已进入分子筛骨架 相似文献
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荷电膜的膜电位研究进展 总被引:1,自引:0,他引:1
膜电位的测定是表征荷电膜的传递现象的重要参数之一。本文简要介绍了膜电位理论基础,包括T. M. S.理论和不可逆热力学理论。分别阐述了关于离子交换膜、双极膜、两性膜以及复合膜的膜电位的最新进展,并提出今后的发展方向。 相似文献
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Zeolite X membranes were investigated by in-situ hydrothermal synthesis on porous ceramic tubes precoated with zeolite X seeds or precursor amorphous aluminosilicate, and porous α-Al2O3 ceramic tubes with a pore size of 50 200 nm were employed as supports. Zeolite X crystals were synthesized by the classic method and mixed into deionized water as a slurry with a concentration of 0.2 0.5wt%, having a range of crystal sizes from 0.2 to 2μm. Crystal seeds were pressed into the pores near the inner surface of the ceramic tubes, and crystallization took place at 95℃ for 24-96 h. It was also investigated that Boehmite sol added with zeolite X seeds was precoated on ceramic supports to form a layer of γ-Al2O3 by heating, and hydrothermal crystallization could then take place to prepare the zeolite membranes on the composite ceramic tubes. The crystal species were characterized by XRD, and the morphology of the supports subjected to crystallization was characterized by SEM. The composite zeolite membranes have zeolitic top-layers with a thickness of 10-25 μm, and zeolite crystals can be intruded into pores of the supports as deeply as 100μm. The experimental results indicate that the precoating of zeolitic seeds on supports is beneficial to crystallization by shortening the synthesis time and improving the membrane strength. The resulting zeolite X membrane shows permselectivity to tri-n-butylamine((C4H9)3N) over perfluro-tributyl-amine ((C4Fg)3N), and a permeance ratio of 57 for ((C4Hg)3N to (C4F9)3N could be reached at 350℃. Permeances of BZ, EB and TIPB through the zeolite membrane were also measured and were found to slightly increase with temperature. 相似文献
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PREPARATIONOFSILICALITE┐1ANDZSM┐5ZEOLITE/CERAMICCOMPOSITEMEMBRANESZhangLixiong,JiaMengdong,MinEnze(ResearchInstituteofPetrole... 相似文献
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Zhongqiang Xu Qingling Chen Guanzhong LuShanghai Research Institute of Petrochemical Technology Shanghai ChinaInstitute of Industrial Catalysis East China University of Science Technology Shanghai China 《天然气化学杂志》2002,(Z2)
Zeolite X membranes were investigated by in-situ hydrothermal synthesis on porous ceramic tubes precoated with zeolite X seeds or precursor amorphous aluminosilicate, and porous α-Al2O3 ceramic tubes with a pore size of 50-200 nm were employed as supports. Zeolite X crystals were synthesized by the classic method and mixed into deionized water as a slurry with a concentration of 0.2-0.5wt%, having a range of crystal sizes from 0.2 to 2μm. Crystal seeds were pressed into the pores near the inner surface of the ceramic tubes, and crystallization took place at 95℃ for 24-96 h. It was also investigated that Boehmite sol added with zeolite X seeds was precoated on ceramic supports to form a layer of r-Al2O3 by heating, and hydrothermal crystallization could then take place to prepare the zeolite membranes on the composite ceramic tubes. The crystal species were characterized by XRD, and the morphology of the supports subjected to crystallization was characterized by SEM. The composite zeolite membranes hav 相似文献
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A model of the composite membrane consisting of the catalytic layer (CL) and the nanofiltration layer (NFL) is presented. It has been found that applying NFL on the permeate side of CL it is possible to enhance substantially the conversion of substrate into the product. The best performance is obtained for high retention of substrate and low of product. At higher values of volume flow and/or longer catalytic path the retention degree of product becomes negligible. The presence of NFL enhances the influence of distribution of the reaction rate constant, k, on the conversion ratio. Comparing to k = constant the positive effect is obtained if k increases along the catalytic pore, whereas negative—if k decreases. 相似文献