共查询到12条相似文献,搜索用时 93 毫秒
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在TMEDA(四甲基乙基二胺)-Na2O-SiO2-Al2O3-H2O体系(I),Na2O-K2O-Al2O3-SiO2-H2O-HCO3^--CO3^2^-体系(II)及Py(吡啶)-PrNH2(正丙胺)-HF-SiO2-H2O体系(III)中, 分别合成了纯相FER沸石及FER硅沸石。用粉末XRD, FT-IR, 29Si MAS NMR及TG/DTA等表征其结构性质, 并用超微量电子真空吸附天平测定这些沸石样品对正己烷, 甲醇和水的吸附等温线。结果表明: 各体系合成的样品虽然结晶度高, 呈现出FER沸石的典型结构特征, 但由于它们的组成和晶格微结构不同, 热稳定性与吸附性质有明显的差异。在(I)体系中合成的FER沸石层错缺陷少, 晶格完美, 正己烷与甲醇的吸附量可达到理论值, 结构破坏温度为1190℃。红外精细谱及29Si MAS NMR高分辨谱证明FER硅沸石具有十分完美的骨架结构。由于晶胞收缩, 它对正己烷与甲醇吸附量略低于理论值, 并呈现出高度的疏水性。它的结构破坏温度高于1300℃。在(II)体系中合成的FER型沸石结构缺陷多, 沸石孔中的钾离子不易被质子完全交换。它的正己烷与甲醇吸附量均较低, 而水的吸附量相对较高。吸附现象表明, 正己烷和甲醇都被吸附于FER沸石的十元环主孔道中, 分压较高时, 甲醇可通过八元环进入小笼, 而水的吸附性质则主要与各样品的Si-OH缺陷及骨架中的阳离子含量有关。 相似文献
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An observation of palladium membrane formation on a porous stainless steel substrate by electroless deposition 总被引:4,自引:0,他引:4
Zhongliang Shi Shanqiang Wu Jerzy A Szpunar Mustapha Roshd 《Journal of membrane science》2006,280(1-2):705-711
The membranes made of palladium and its alloys are used for the extraction of high quality hydrogen from a mixture of gases. Most of recent research is focused on the development technologies for depositing a durable ultra-thin palladium membrane on a porous substrate in order to assure a good mechanical support and maximize the flux of hydrogen permeation. The formation of a palladium membrane deposited on a porous stainless steel substrate by an electroless process is recorded and described in this paper. The palladium deposition progress around the pore area at the surface of the substrate in the initial stages is illustrated. A bridge model is presented to describe the membrane formation around the pore area of the substrate. This model, together with the micrographs showing the deposition progress on the pore areas, will lead to the control of the deposition process for a membrane fabrication as well as the design and modification of a substrate. 相似文献
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MFI型沸石分子筛,由于其具有较宽合成条件、合适均的一孔径、可修饰和改 性的骨架和孔道系统,高的热稳定性、水热稳定性、化学稳定性和机械强度,不仅 广泛应用于传统的催化和分离领域,而且也广泛地应用于膜的制备。由于MFI型沸 石晶体体型和晶内孔道系统 的各向异性,控制晶体在载体表面的定向生长对于膜 分离、膜催化、膜传感等都极其重要的。文献中报道的c轴取向MFI型沸石膜层的制 备方法有:(1)晶体在强电场作用下在载体表面上进行定向排 列,然后在排列好 的晶体间喷镀或电镀一层金属膜;(2)在有刻蚀槽的微结构硅片表面进行组装; (3)水热合成法;(4)晶种层的二次生长法等。 相似文献