共查询到20条相似文献,搜索用时 875 毫秒
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陶瓷微滤膜载体作为无机膜的基础,对于膜层的制备和无机膜的使用稳定性都有着重要影响。要制备性能良好的无机膜,首先必须要有髙质量耐酸碱性能良好的陶瓷微滤膜载体。本文采用干压成型法,对Al2O3-SiO2-TiO2体系样品进行了烧结性能、抗折强度和耐酸碱腐蚀的研究。研究结果表明,以96%的?-Al2O3(粒径20μm )为骨料,添加3%的硅溶胶以及1%的二氧化钛的微滤膜载体在1400益烧成,可获得具有较髙的抗折强度及良好的耐酸碱性能的样品。 相似文献
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以粒径为0.3~0.4 μm的α-Al2O3为原料,通过悬浮液真空抽吸法,制备出平均孔径约为70 nm的完整无缺陷的片状α-Al2O3支撑体;以仲丁醇铝为前驱体,采用颗粒溶胶路线制备出稳定的Boehmite溶胶,以此溶胶采用浸浆法,在制备的α-Al2O3支撑体上制备出完整无缺陷的γ-Al2O3中孔膜,并考察了烧成温度对γ-Al2O3中孔膜性能的影响。结果表明,本文制备出的γ-Al2 O3膜的孔径约为3 nm,对PEG的截留分子量为2800~5300,纯水渗透通量为11.5~25.9 L.m-2.h-1[7.6×105 Pa,(14±1)℃]。说明在孔径为70 nm左右的载体上直接制备孔径为3 nm的完整的中孔膜是可行的。 相似文献
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Marco Facciotti Vittorio Boffa Giuliana Magnacca Lars Bjerg Jørgensen Peter Kjær Kristensen Ali Farsi Katja König Morten Lykkegaard Christensen Yuanzheng Yue 《Ceramics International》2014
Porous SiC based materials present high mechanical, chemical and thermal robustness, and thus have been largely applied to water-filtration technologies. In this study, commercial SiC microfiltration tubes with nominal pore size of 0.04 μm were used as carrier for depositing thin aluminum oxide (Al2O3) ultrafiltration membranes. These ultrafiltration membranes were obtained by coating, drying and calcination of a colloidal suspension of boehmite particles. After calcination, the membrane material consisted of nanosized γ-Al2O3 crystallites and had a narrow pore size distribution with average pore size of 5.5 nm. Membrane thickness was tuned by repeating the coating of boehmite sol. By doing so, we were able to reduce the defect density on the membrane surface, as evidenced by SEM analysis and by the significant reduction of water permeance after depositing the second γ-Al2O3 layer. After five times coating, a 5.6 µm thick γ-Al2O3 layer was obtained. This membrane shows retention of ~75% for polyethylene glycol molecules with Mn of 8 and 35 kDa, indicating that, despite their intrinsic surface roughness, commercial SiC microfiltration tubes can be applied as carrier for thin ultrafiltration membranes. This work also indicates that an improvement of the commercial SiC support surface smoothness may greatly enhance permeance and selectivity of γ-Al2O3 ultrafiltration membranes by allowing the deposition of thinner defect-free layers. 相似文献
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Al2O3 hollow fibres with different asymmetric macrostructures, i.e. various thickness ratios between a finger-like layer and a sponge-like layer, have been prepared by a phase inversion/sintering technique. Such asymmetric hollow fibres are used as substrates on which Pd membrane is deposited directly by an electroless plating (ELP) technique without any pre-treatment on substrate surface. Influences of the substrate macrostructure on hydrogen permeation through the Pd/Al2O3 composite membranes have been investigated both experimentally and theoretically. The hydrogen permeation through the Pd/Al2O3 composite membranes was not only determined by the Pd membrane thickness, but also by the macrostructural parameters of the substrate, such as effective porosity, mean pore size and pore size distribution etc. The thinner the Pd membrane, the higher the effective porosity is required to alleviate the substrate effect on the hydrogen permeation. Also, the deviation of the pore size is suggested to be around 1.2 for the further improved hydrogen permeation through the composite hollow fibre membranes. 相似文献
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在毛细过滤和薄膜形成机理的基础上,采用化学工程实验与模型化方法,对浸浆成型法制备多孔α-Al2O3陶瓷膜过程中,膜厚与影响因素之间的关系进行了理论分析和实验研究. 结果表明:膜厚受到制膜液粉体浓度、制膜液黏度、粉体粒径大小、载体纯水渗透性能以及涂膜过程中浸浆时间和载体提升速度等因素的影响. 通过膜厚与影响因素间的数学模拟,建立了膜厚控制模型. 并以ZrO2粉体为原料,采用相同方法制备ZrO2陶瓷膜对模型进行了验证,模拟计算值与实测值基本一致. 相似文献
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Ruixia Shi Yaru Shang Yan Zhang Peng Wang Aiyu Zhang Ping Yang 《Ceramics International》2018,44(4):3741-3750
The ultrafine α-Al2O3 powder has been successfully synthesized via two-step hydrolysis of aluminum isopropoxide. The effects of synthesis parameters on the α-Al2O3 were investigated. The experimental results indicated that the concentration of aluminum isopropoxide, water bath temperature, the molar ratio of aluminum isopropoxide to isopropanol and aluminum isopropoxide to deionized water greatly affect the amount of nuclei and the microstructure of α-Al2O3. Additionally, the water bath temperature affects the rate of nucleation and growth of crystals. Transmission electron microscopy (TEM) images display that the well-dispersed α-Al2O3 powder with particle size about 100 nm was obtained via the method after calcination at 1200 °C for 1 h. The coalescence of crystal particles led to the formation of vermicular α-Al2O3 particles. The X-ray diffraction (XRD) and Fourier transform infrared spectra (FTIR) analysis demonstrated the possible phase transition process of α-Al2O3. The scanning electron microscopy (SEM) images of samples calcined at various temperatures showed the microstructure transformation. Brunauer-Emmett-Teller (BET) surface area and mean pore size of the samples varied with the calcination temperature. The addition of cetylrimethylammonium bromide (CTAB) has impacts on the phase transformation of α-Al2O3. 相似文献
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分别以吡咯烷和正丁胺为模板剂,在多孔α-Al2O3陶瓷管(3~5 μm)外表面上原位直接合成出ZSM-35型沸石膜,XRD、SEM对沸石膜进行表征和单组分气体H2、N2 和C3H8的渗透性能测试表明:所合成出的沸石膜表面连续完整,晶粒之间互锁生长,沸石膜的厚度约为12~18 μm,具有典型的ZSM-35沸石结构,不同的模板剂对沸石膜的表面形态影响较大;经不同焙烧温度处理的沸石膜, 随着处理温度增高, 沸石膜表面晶粒的排列沿(h 0 0)取向性明显增强;所合成的沸石膜在室温下单组分气体H2、N2和C3H8渗透率达到10-6数量级,H2/N2 和H2/C3H8理想分离因数均超过Knudsen扩散. 相似文献
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H2O2沉淀铝酸钠溶液法制备大孔容纳米γ-Al2O3纤维粒子 总被引:5,自引:1,他引:5
采用H2O2沉淀铝酸钠溶液和乙醇分散并洗涤沉淀相结合的方式成功地制备出了大孔容纳米γ-Al2O3纤维.运用XRD、FT-IR、TG-DSC、TEM、BET和压汞法对比研究了水洗和乙醇分散并洗涤两种沉淀处理方式对产物结构、形貌和织构性质的影响.结果表明,乙醇洗涤产物γ-Al2O3纤维的直径约为10 nm,长度约在100 nm以上,孔容和比表面分别为2.23 ml8226;g-1和222.0 m28226;g-1,而水洗γ-Al2O3的二次粒子无固定形状,孔容和比表面仅为0.37 ml8226;g-1和162.3 m28226;g-1.乙醇洗涤时形成的CH3CH2O—基不仅使γ-Al2O3前驱物拟薄水铝石晶粒定向生长成纤维,还阻止了相邻颗粒表面之间因Al—O—Al键形成而产生的硬团聚. 相似文献
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以FeCrAl合金薄片为基体,Pt-Sn-Li/γ-Al2O3为活性涂层,制备了Pt-Sn-Li/Al2O3/FeCrAl金属基复合载体负载型催化剂。采用XRD、SEM、TPR等手段对催化剂进行了表征,并在微型固定床反应器中考察了不同反应温度、液时空速和氢/烃摩尔比下对长链烷烃脱氢的催化性能。结果表明,将活性浆料直接涂覆于焙烧后的金属薄片上制得的催化剂有良好的结合性能,经超声波振荡后涂层脱落率小于2%。当Pt-Sn-Li/γ-Al2O3活性涂层涂覆到FeCrAl金属基体后复合载体Al2O3/FeCrAl与活性成分的相互作用明显增强。催化反应性能评价表明,较高的反应温度有利于长链烷烃脱氢过程,但温度过高时将加速催化剂积炭失活。较低的空速有利于十二烷的转化,但进一步减小空速将造成十二烯的选择性明显降低。减小氢/烃摩尔比虽然有利于提高十二烷的转化率,但进一步减小氢/烃摩尔比也将加速催化剂积炭失活。 相似文献
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采用浸渍法制备了RuO2/γ-Al2O3催化剂,以苯酚为目标有机物重点研究了进水pH值和温度对RuO2/γ-Al2O3催化剂组分溶出和活性的影响.结果表明,催化剂在降解苯酚过程中存在着组分溶出现象,随着进水溶液pH值降低催化剂组分溶出量增加,且在进水为酸性时苯酚去除率高于碱性时的去除率.反应温度升高,催化剂组分溶出量降低,苯酚去除率增加.采用在负载型RuO2/γ-Al2O3催化剂中掺杂Ce和Zr的方法对抑制催化剂组分溶出进行了初步研究,发现掺杂Ce和Zr后有效地降低了RuO2/γ-Al2O3催化剂组分的溶出,且提高了催化剂的活性. 相似文献