共查询到20条相似文献,搜索用时 15 毫秒
1.
Kimiaki Tsutsui Hiroaki Yoshimizu Yoshiharu Tsujita Takatoshi Kinoshita 《应用聚合物科学杂志》1999,73(13):2733-2738
The permeability coefficients of O2, N2, and CO2 gases at 25°C were examined for composite membranes that were prepared by filling poly(ethylene oxide)(PEO) with different molecular weights into a porous membrane. The permeability coefficients of O2, N2, and CO2 were 2 × 10−10 – 4 × 10−10, 5 × 10−11 – 9.5 × 10−11, and 6 × 10−10 – 1 × 10−9 (cm3 STPcm/cm2 s cmHg), respectively. The higher permeability coefficients of CO2 are explained in terms of high solubility of CO2 in filled PEO. The permeability coefficient of CO2 was affected by the degree of crystallinity of PEO in the composite. On the other hand, there was little effect of crystallinity on O2 and N2 permeability coefficients. Some probable relationships between selectivities of O2 to N2 and CO2 to N2 and the degree of crystallinity of PEO were observed. The CO2 gas permeability coefficients of the composite membrane for PEO50000 (Mw = 5 × 104) showed a marked change due to melting or crystallization of PEO. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 2733–2738, 1999 相似文献
2.
Matthias Schulz Ute Pippardt Lutz Kiesel Katrin Ritter Ralf Kriegel 《American Institute of Chemical Engineers》2012,58(10):3195-3202
Ba0.5Sr0.5Co0.8Fe0.2O3‐δ tubes, capillaries, capillary modules, and asymmetric membranes were prepared and tested for oxygen permeation in a dead‐end vacuum operation mode at temperatures up to 850°C. The capillary module was built up by reactive air brazing using seven capillaries and a supply tube. Two machined discs were used as an end cap and as a connector plate. The oxygen permeation behaves according to Wagner at small driving forces, but significant negative deviations were observed for asymmetric membranes and single capillaries at higher ones. This is caused by pressure drops at the vacuum side for single capillaries. The highest oxygen flux was revealed for the capillary module with 175.5 mL(STP)/min at a low‐vacuum pressure of 0.042 bar at 850°C, but the asymmetric membrane showing a little bit higher flux at moderate vacuum pressures above 0.07 bar. © 2012 American Institute of Chemical Engineers AIChE J, 58: 3195–3202, 2012 相似文献
3.
Luolin Yang Zhongwei Cao Yue Zhu Jingyi Wang Bingjie Pang Wenhao Zhang Liming Zhang Shiqing Hu Xuefeng Zhu Weishen Yang 《Ceramics International》2021,47(13):18510-18516
Two capillary membranes, single-phase Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) and dual-phase 75 wt% Ce0.85Sm0.15O1.925 - 25 wt% Sm0.6Sr0.4Cr0.3Fe0.7O3-δ (SDC-SSCF), with dense cross section, were successfully prepared through the plastic extrusion method. The dual-phase capillary membrane shows higher strength compared to the BSCF counterpart, while the two capillary membranes exhibit much higher fracture strength than those of hollow fiber membranes. The oxygen permeation fluxes of both membranes increase with the increase of temperature and flow rate of sweep gas at the ambient pressure, and can be greatly improved by applying high pressures to the feed side. The oxygen permeation flux of BSCF capillary membrane is up to 19.5 mL cm?2 min?1 when 0.5 MPa air was applied to the feed side at 900 °C, which is one order of magnitude higher than that of SDC-SSCF capillary membrane. Thus, both capillary membranes have their own advantages and meet applications under different operation conditions. 相似文献
4.
Laura Bueso Marta Osorio‐Galindo Isabel Alcaina‐Miranda Amparo Ribes‐Greus 《应用聚合物科学杂志》2000,75(11):1424-1433
Novel hydrophobic composite membranes made of crosslinked poly(dimethylsiloxane) and poly(methyl hydrogen siloxane) (PDMS–PMHS) with various amounts of catalyst were prepared. Pervaporation experiments with water–ethanol mixtures revealed that an optimum ratio of catalyst to polymer base existed. Both swelling behavior and dynamic–mechanical properties of these silicone films were studied. The swelling experiments in different mixtures of ethanol and water determined that ethanol is preferentially sorbed and that the membranes are only capable to absorb a limited quantity of solvent. Equilibrium swelling data were also used in combination with the analysis of the viscoelastic relaxation of the swollen samples to obtain the dependence of the dynamic–mechanical properties of the silicone films on the quantity of permeants sorbed into the membrane. It was observed that the permselective parameters were related with the mobility of the chains and the free volume. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1424–1433, 2000 相似文献
5.
Silk fibroin/chitosan (SF/CS) blend membranes were prepared and characterized by infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy. It was found that SF and CS were compatible in the blend membranes and that the membranes were dense without microscopic phase separation. Swelling experiments showed that the swelling ratio of the blend membranes increased with CS content and reached the highest value when CS content was 70 wt%. Experiments indicated that the permeability coefficient of K+ through the blend membrane was 2–4 times higher than that of pure CS membrane, and 10 times higher than that of pure SF membrane. The permeation rate of K+ increased linearly with CS content in the blend membrane for the lower concentration feeding solution. For different metal ions, the permeability through SF/CS blend membranes was in the sequence K+ > Ca2+ > Cd2+ > Pb2+ > Cu2+ > Ni2+. Copyright © 2006 Society of Chemical Industry 相似文献
6.
The permeation of potassium chloride through γ-irradicated nylon-6 membranes grafted with acrylic acid (AA) was investigated. The permeability of potassium chloride increases with increasing levels grafting in the membrane. It was found that the theory of permeation of electrolyte through ionic membranes (derived from the phenomenological equation) was applicable to the permeation of potassium chloride through AA-grafted membrane with high levels of grafting. The effective concentration of fixed charge determined by the Donnan membrane equilibrium exhibited almost the same value in the grafted membrane regardless of the levels of grafting. It was found that a tortuosity factor was dominant through affecting the permeation of KCI through the membrane. This may be considered as an interference factor in a homogeneous membrane. 相似文献
7.
In this work, a new polydimethylsiloxane (PDMS) membrane was synthesized and its sorption, diffusion, and permeation properties were investigated using H2, N2, O2, CH4, CO2, and C3H8 as a function of pressure at 35°C. PDMS, as a rubbery membrane, was confirmed to be more permeable to more condensable gases such as C3H8. The synthesized PDMS membrane showed much better gas permeation performance than others reported in the literature. Based on the sorption data of this study and other researchers' works, some valuable parameters such as Flory‐Huggins (FH) interaction parameters, χ, etc., were calculated and discussed. The concentration‐averaged FH interaction parameters of H2, N2, O2, CH4, CO2, and C3H8 in the synthesized PDMS membrane were estimated to be 2.196, 0.678, 0.165, 0.139, 0.418, and 0.247, respectively. Chemical similarity of O2, CH4, and C3H8 with backbone structure of PDMS led to lower χ values or more favorable interactions with polymer matrix, particularly for CH4. Regular solution theory was applied to verify correctness of evaluated interaction parameters. Local effective diffusion coefficient of C3H8 and CO2 increased with increasing penetrant concentration, which indicated the plasticization effect of these gases over the range of penetrant concentration studied. According to high C3H8/gas ideal selectivity values, the synthesized PDMS membrane is recommended as an efficient membrane for the separation of organic vapors from noncondensable gases. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
8.
以苯酚为模型污染物,以氢氧化钠溶液为萃取液,利用平板复合膜[聚二甲基硅氧烷(PDMS)/聚偏氟乙烯(PVDF)]构造渗透萃取体系,系统地研究了该体系渗透萃取含酚水溶液的传质过程与特性。探讨了料液与萃取液的浓度及流量、运行温度等操作条件及活性层厚度对渗透萃取传质性能的影响。结果表明,pH>13时,总传质系数Kov不随萃取液流量及浓度变化而变化;苯酚的液膜传质系数kf与膜面流动Reynolds数Re0.46呈正比,传质通量与温度符合Arrhenius方程。在苯酚初始浓度5.0~15.0 g8226;L-1范围内,Kov为定值。活性皮层厚度为4、6、8 μm的膜扩散传质系数分别为15.0×10-7、9.9×10-7及7.5×10-7m8226;s-1(323.2 K),较均质膜提高了2~4倍。苯酚在复合膜中的传质仍属膜阻控制的传质。 相似文献
9.
Zi‐Yong Zhang 《应用聚合物科学杂志》2003,90(4):1038-1044
A novel silicone polymer membrane with facilitated oxygen transport properties was prepared by using 11‐alkene acid cobalt, a silicone rubber containing vinyl groups of 5 mol %, a hydrogen‐containing silicon oil, and chlorine platinum acid. The solution casting and the vulcanization were carried out simultaneously at room temperature. Investigation showed that PO 2 increased and PN 2 did not change with decreasing gas pressure difference. This facilitated oxygen transport behavior was contributed by a polymeric cobalt complex formed from carboxylic groups and cobaltous ions in the membrane to result in the simultaneous increase of both PO 2 and αO 2/N 2 under lower gas pressure difference. For example, the PO 2 and αO 2/N 2 of the membrane containing 11‐alkene acid cobalt of 2.5 wt% were 750 Barrer and 3.09 under a gas pressure difference of 0.05 mPa. As much as 5 wt% 11‐alkene acid cobalt could be added to the membranes; PO 2 and αO 2/N 2 increased to 802 Barrer and 3.34 respectively when the membrane contained 11‐alkene acid cobalt of 5 wt %. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1038–1044, 2003 相似文献
10.
以六甲基二硅氮烷为改性剂,采用湿法工艺对纳米Si O2进行表面疏水化改性,制备了用于离子迁移谱仪进样的纳米Si O2增强硅橡胶膜,考察了加热温度与反应时间对纳米Si O2的改性效果,研究了改性纳米Si O2与硅橡胶的相容性、纳米Si O2掺杂硅橡胶膜的厚度及拉伸性能。结果表明,在疏水化改性反应中,随着加热温度的升高或反应时间的延长,纳米Si O2表面羟基数下降,比表面积减小,最佳加热温度为120℃,反应时间为4 h;随着反应时间的延长,改性纳米Si O2与硅橡胶的混合液透光度增大,说明纳米Si O2与硅橡胶的相容性提高;以聚苯乙烯为基底材料,采用溶剂挥发工艺制得纳米Si O2掺杂硅橡胶膜的拉伸强度随着纳米Si O2掺杂量的增加而增大,当纳米Si O2与硅橡胶掺杂质量比为30∶100时,可制得厚为2~5μm的最薄硅橡胶膜。 相似文献
11.
Cristina Tablet Gerd Grubert Haihui Wang Thomas Schiestel Michael Schroeder Bernd Langanke Jü rgen Caro 《Catalysis Today》2005,104(2-4):126-130
The first oxygen permeation data of a dense hollow fiber perovskite membrane based on BaCoxFeyZrzO3 − δ are reported. The hollow fiber was prepared by a phase inversion process. Dense fibers were obtained with the following typical geometries: outer diameter, 800–900 μm; inner diameter, 500–600 μm; length, 30 cm. The O2-permeation through the hollow fiber perovskite membrane was studied in a high-temperature gas permeation cell under different operation conditions. The increase of the helium gas flow rate reduces the oxygen partial pressure (pO2) on the core side and a higher oxygen permeation flux is observed. High oxygen flux of 0.73 m3 (O2)/(m2 (membrane) h) was achieved at 850 °C under the operation parameters Fair (shell side) = 150 ml/min and FHe (core side) = 30 ml/min. The oxygen partial pressure dependence of the O2 permeation flux indicated an interplay of both surface reaction and bulk diffusion as rate limiting steps. During 5 days of permeation a high and stable oxygen flux was observed. X-ray diffraction patterns of fresh and spent membranes after the permeation measurements revealed that no degradation after oxygen permeation appears. 相似文献
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Satoshi Kitaoka Tsuneaki Matsudaira Daisuke Yokoe Takeharu Kato Masasuke Takata 《Journal of the American Ceramic Society》2017,100(7):3217-3226
The oxygen permeability of polycrystalline mullite wafers, serving as a model environmental barrier coating layer on SiC fiber‐reinforced SiC matrix composites, was evaluated at temperatures above 1673 h with an oxygen tracer gas (18O2). Oxygen permeation occurred by grain‐boundary (GB) diffusion of oxygen from the high oxygen partial pressure (high‐Po 2) surface to the low‐Po 2 surface, with simultaneous GB diffusion of aluminum in the opposite direction. This GB interdiffusion of both oxygen and aluminum proceeded without acceleration or retardation, maintaining the Gibbs‐Duhem relationship. Oxygen permeation related to the GB diffusion of silicon was negligibly small compared to that generated by aluminum GB diffusion, resulting in decomposition of the mullite near the low‐Po 2 surface. The GB diffusion coefficients for oxygen in the vicinity of the high‐Po 2 surface were determined directly from the SIMS‐18O line profiles along individual GBs, as assessed from cross sections of the exposed wafer. The coefficients thus obtained were comparable to those determined in the absence of an oxygen potential gradient and those calculated from an oxygen permeation trial under the assumption of nearly ionic conductivity. 相似文献
14.
Akon Higuchi Toshihiro Agatsuma Shigeyuki Uemiya Toshinori Kojima Keishin Mizoguchi Ingo Pinnau Kazukiyo Nagai Benny D. Freeman 《应用聚合物科学杂志》2000,77(3):529-537
Fullerene‐dispersed membranes were homogeneously prepared under the conditions in which a 10 wt % polystyrene solution containing 1 wt % fullerene was dried under a reduced pressure of 50 cmHg at room temperature. The fullerene membranes prepared with 1,2‐dichlorobenzene were found to have the darkest color, and showed no evidence of fullerene crystals in their photomicrographs. UV‐visible and infrared absorption spectra of the fullerene membranes showed fullerene bands, which indicated that the fullerene was homogeneously dispersed in the membranes. The permeability coefficients of pure nitrogen, oxygen, carbon dioxide, ethane, and ethylene were found to increase significantly in the fullerene membranes compared to those in the polystyrene membranes, although the ideal separation factors for oxygen/nitrogen and ethylene/ethane in the fullerene membranes (i.e., 4.3 and 1.7, respectively) were slightly less than the separation factors in the polystyrene membranes. The permeability increase originated from the increase in diffusion coefficients in the fullerene membranes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 529–537, 2000 相似文献
15.
In this study, poly(dimethyl siloxane) (PDMS)/poly(vinylidene fluoride) (PVDF), poly(phenyl methyl siloxane) (PPMS)/PVDF, poly(ethoxy methyl siloxane) (PEOMS)/PVDF, and poly(trifluropropyl methyl siloxane) (PTFMS)/PVDF composite membranes were prepared. The different functional compositions of these membranes were characterized by Fourier transform infrared spectroscopy. The surfaces and sections of these membranes were investigated by scanning electron microscopy. The hydrophobicity at the membrane surface was assessed with contact angle measurement. Swelling experiments were carried out to investigate the swelling behavior of these membranes. The composite membranes prepared in this study were used in the pervaporation separation of ethanol/water mixtures, and their separation performances were compared. The results show that the separation performances of these membranes were strongly related to the silicone rubber components and composition, the total fluxes decreased in the following order: PDMS > PPMS > PEOMS > PTFMS. The separation factor followed the following order: PPMS > PEOMS > PDMS > PTFMS (5 wt % ethanol at 40°C). In addition, the effects of the feed temperature (40–70°C) and feed composition (5–20 wt %) on the separation efficiency were investigated experimentally. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
16.
Oxygen permeation characteristics of sol‐gel derived barium‐substituted strontium ferrite membranes
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Shivendra Kumar Jaiswal Jitendra Kumar 《Journal of the American Ceramic Society》2017,100(4):1306-1312
The pervoskite‐type oxides have received attention due to their potential applications in catalysis, solid oxide fuel cells, gas sensors, and gas separable membranes. In view of their importance in oxygen separation from air, BaxSr1?xFeO3?δ (0≤x≤1.0) samples have been synthesized by sol‐gel process and investigated with regard to phase(s), oxygen permeation, and electrical conductivity. These compounds possess at room temperature, a perovskite‐type cubic, mixture of rhombohedral and hexagonal, and hexagonal phase(s) depending upon the composition 0≤x≤0.94, x=0.96‐0.98, and x=1.0, respectively. The barium incorporation causes initially enhancement but decrease in electrical conductivity above x=0.94. Above 800°C, all the compositions exhibit a stable cubic phase. The compacts made in the form of discs serve as stable oxygen permeable membranes displaying flux density () of ~2.45‐3.58 mL/cm2.min at 1000°C. A good correlation has been demonstrated between the oxygen permeation and the electrical conductivity data. The maximum values of and conductivity correspond to BaxSr1?xFeO3?δ (x=0.94) with a perovskite‐type cubic structure. Hence, this membrane is quite suitable for oxygen separation technology. 相似文献
17.
论文研究了甲基硅橡胶膜(PDMS)和乙烯基硅橡胶膜(PVMS)对一元羧酸的渗透萃取效果,建立了有机物结构参数与膜渗透萃取效果的关系。研究发现,PVMS膜比PDMS膜对一元羧酸有较好的萃取效果。结合一元羧酸结构参数与硅橡胶膜结构,对渗透萃取效果进行分析。结果表明:对于硅橡胶膜,随着有机物辛醇-水分配系数(Kow或P)、分子摩尔体积(Vm)、分子极化率(a)的增大,固有溶解度(S)的减小,一元羧酸的萃取率依次升高;经线性回归拟合分析,辛醇-水分配系数(Kow或P)与硅橡胶膜萃取率有良好的相关性(R2均在0.96以上);分子摩尔体积(Vm)对硅橡胶膜萃取率表现出一定的相关性(R2均在0.81以上);偶极矩(u)并未有表现出明显的规律性。 相似文献
18.
Masaaki Teramoto Nobuaki Ohnishi Nao Takeuchi Satoru Kitada Hideto Matsuyama Norifumi Matsumiya Hiroshi Mano 《Separation and Purification Technology》2003,30(3):215-227
A novel facilitated transport membrane for gas separation using a capillary membrane module is proposed in which a carrier solution is forced to permeate the membrane. Both a feed gas and a carrier solution are supplied to the lumen side (high pressure side, feed side) of the capillary ultrafiltration membrane and flow upward. Most of the carrier solution which contains dissolved solute gas, CO2 in the present case, permeates the membrane to the permeate side (low pressure side, shell side), where the solution liberates dissolved gas to form a lean solution. The lean solution is circulated to the lumen side. This type of capillary membrane module was applied to the separation of CO2 from model flue gases consisting of CO2 and N2. Monoethanolamine (MEA), diethanolamine (DEA) and 2-amino-2-methyl-1-propanol (AMP) were used as carriers or absorbents of CO2. The feed side pressure was atmospheric and the permeate side was evacuated at about 10 kPa. CO2 in the feed gas was successfully concentrated from 5–15% to more than 98%. The CO2 permeance was as high as 2.7×10−4 mol m−2 s−1 kPa−1 (8.0×10−4 cm3 cm−2 s−1 cmHg−1) when the CO2 mole fraction in the feed was 0.1 and temperature was 333 K. The selectivity of CO2 over N2 was in the range from 430 to 1790. The membrane was very stable over a discontinuous one-month testing period. 相似文献
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有机硅纳米杂化改性环氧胶的研制和应用 总被引:1,自引:0,他引:1
通过溶胶-凝胶法制备了纳米有机硅溶胶。用透射电镜和红外光谱表征和分析了纳米粒子的形态和粒径,粒径为30-70nm。制备了用活性稀释剂糠醛和丙酮及有机硅纳米杂化改性的环氧胶。研究了胶液的初始黏度、渗透性、力学强度、弹性模量、粘接性、表面疏水性和防腐蚀性能。实验结果表明,环氧树脂含量、有机硅溶胶、硅烷偶联剂等对改性环氧胶的这些性能有显著影响,改性环氧胶双组分混合液的初始黏度可低至1.1mPa·s,渗透性强,固结体抗压强度高达40.8-81.5MPa,弹性模量为1.3-2.1×10^3MPa,剪切粘接强度5.1-11.9MPa,防水抗渗性及防腐蚀耐候性良好,可应用于灌浆防水加固补强、工业地坪涂料和防腐蚀涂料等多种用途。 相似文献