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1.
近年来,将金属-有机骨架材料(MOFs)和膜基材料结合,制备新型MOFs分离膜成为膜领域研究的热点之一。由于MOFs具有类似分子筛结构和空间拓扑结构,在分离、催化等方面具有潜在的应用前景。沸石咪唑框架材料(ZIFs)作为MOFs中重要分支之一,因其具有优异的热稳定性和化学稳定性被应用于膜分离。本工作重点阐述了原位生长、界面反扩散、逐层组装、二次生长、气相沉积和微流体处理等方法制备ZIFs多晶膜和杂化膜,并系统介绍了ZIFs复合膜在染料与重金属离子去除、气体分离、天然气净化、生物医药和电化学传感中的应用。最后,总结了ZIFs复合膜制备过程中存在的问题和挑战,并对ZIFs复合膜未来研究的方向提出了展望。 相似文献
2.
Synthesis of zeolitic imidazolate frameworks (ZIF)‐8 membrane and its process optimization study in separation of CO2 from natural gas 下载免费PDF全文
Li Sze Lai Yin Fong Yeong Kok Keong Lau Azmi Mohd Shariff 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2017,92(2):420-431
3.
采用二次生长法在α-Al2O3载体上制备超薄型ZIF-8膜,研究了多种轻分子气体以及混合气体CO2/N2的渗透分离性能。通过SEM和XRD表征了ZIF-8晶种层的晶种涂布状态,以及ZIF-8晶体膜的生长覆盖度和晶膜厚度。研究结果表明:采用低浓度的晶种悬浮液通过浸润式连续多次涂布法,有利于获得晶种层厚度均匀且覆盖度高的超薄均匀ZIF-8晶种层,经过二次生长后所得ZIF-8膜的覆盖度高、厚度均匀且较薄,仅约为8.8 μm;在所测试范围内的CO2/N2混合气体中,此ZIF-8膜对CO2具有优先选择透过性,其对CO2/N2的渗透分离因子随温度的升高而降低,随渗透压力的增加而增加,在298 K、406 kPa和CO2组分含量为50%时,该分离因子能达到6,显著超过Knudsen扩散的分离系数。 相似文献
4.
《Carbon》2014
The preparation, characterization and CO2 uptake performance of N-doped porous carbon materials and composites derived from direct carbonization of ZIF-8 under various conditions are presented for the first time. It is found that the carbonization temperature has remarkable effect on the compositions, the textural properties and consequently the CO2 adsorption capacities of the ZIF-derived porous materials. Changing the carbonization temperature from 600 to 1000 °C, the composites and the resulting porous carbon materials possess a tuneable nitrogen content in the range of 7.1–24.8 wt%, a surface area of 362–1466 m2 g−1 and a pore volume of 0.27–0.87 cm3 g−1, where a significant proportion of the porosity is contributed by micropores. These N-doped porous composites and carbons exhibit excellent CO2 uptake capacities up to 3.8 mmol g−1 at 25 °C and 1 bar with a CO2 adsorption energy up to 26 kJ mol−1 at higher CO2 coverages. The average adsorption energy for CO2 is one of the highest ever reported for any porous carbon materials. Moreover, the influence of textural properties on CO2 capture performance of the resulting porous adsorbents has been discussed, which may pave the way to further develop higher efficient CO2 adsorbent materials. 相似文献
5.
Microwave synthesis of tubular zeolitic imidazolate framework ZIF-8 membranes for CO2/CH4 separation
The separation of CO2/CH4 is reported in detail by using zeolitic imidazolate framework (ZIF-8) membrane which was prepared on 3-aminopropyltriethoxysilane modified Al2O3 tube through microwave heating synthesis. Attributed to the preferential adsorption affinity of CO2 over CH4 and a narrow pore window of 0.34 nm, the ZIF-8 membrane shows high separation performances for the separation of CO2/CH4 mixtures. For the separation of equimolar CO2/CH4 mixture at 100°C and 2 bar feed (1 bar permeate) pressure, a CO2 permeance of 1.02 × 10?8 mol/m2· s· Pa and a CO2/CH4 selectivity of 6.8 are obtained, which is promising for CO2 separation. 相似文献
6.
Samira Mosleh Ghader Khanbabaei Mohammadreza Mozdianfard Mahmood Hemmati 《Iranian Polymer Journal》2016,25(12):977-990
Mixed matrix membranes (MMMs) are gaining increasing interest in academic and industrial research due to their combined, desirable properties of both polymers and organic/inorganic filler as important materials. In this work, synthesized zeolitic imidazolate framework (ZIF-8) suspension (10–50 wt%) was directly incorporated into a [poly (amide-b-ethylene oxide) Pebax® 1657] matrix in order to improve the gas separation performance of the membrane. Dynamic light scattering (DLS) analysis showed an average diameter of 77.4 nm for the prepared nanoparticles. The transparent membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffractometry (XRD). These indicated excellent dispersion of nanoparticles, which was achieved by ultrasonication before casting the solution. Incorporation of ZIF-8 as filler in the polymer matrix led to improved thermal and mechanical stability of the membranes. This was confirmed by TGA and tensile analyses, indicating good contacts provided at the polymer/filler interfaces. The effect of ZIF-8 loading (up to 50 wt%) on membrane performance was investigated and it showed an optimum loading of 30 %. Single gas (CO2, N2 and CH4) permeation tests revealed rapid, enhanced permeability of the nanocomposite membranes without significant changes in selectivity (compared to those of the pristine polymeric membrane). The permeability increases for CO2, CH4 and N2 in the optimum Pebax® 1657/ZIF-8 (30 wt%) membrane were found in the stated order as 111, 88 and 99 %. The study revealed that Pebax® 1657/ZIF-8 membranes displayed better gas permeation properties compared to those of Pebax® 1657. 相似文献
7.
Ihtisham Ul Haq Tao Wang Ao-Shuai Zhang Heng Mao Rehan Khan Li-Hao Xu Zhi-Ping Zhao 《American Institute of Chemical Engineers》2021,67(4):e17114
1,3-Butadiene (BD) is a petrochemical-based volatile organic compound, extensively used for the manufacture of synthetic rubber. There is no method reported for its recovery from nitrogen mixture. Herein, for the first time, BD is efficiently recovered by gas separation through facile and novel mixed-metal ZIF-8 based mixed matrix membranes (MMMs). Addition of Ni-ZIF-8 nanoparticles in PDMS matrix, significantly improved the penetrant-membrane interactions and the solution-diffusion properties of BD. Positron annihilation lifetime spectroscopy analysis showed that the well dispersion of Ni-ZIF-8 in PDMS enhanced the free volume of membrane and created efficient continuous paths for BD diffusion. Then, 15 wt% Ni-ZIF-8 MMM exhibited the BD permeance of 323 GPU and the BD/N2 ideal selectivity of 19.5, which were 60 and 81% higher than pure PDMS membrane, respectively. The simultaneous enhancement of BD permeance and BD/N2 ideal selectivity indicated that Ni-ZIF-8 was an effective filler applied in MMMs for efficient BD recovery. 相似文献
8.
Jiaqi Liu Xuan Tang Xiaowu Liang Luogang Wu Feifei Zhang Qi Shi Jiangfeng Yang Jinxiang Dong Jinping Li 《American Institute of Chemical Engineers》2022,68(5):e17589
Various adsorbents for CH4/N2 separation were developed to enrich low-concentration coal-mine methane. Most are hydrophilic and cannot treat moist coal-mine methane. We report for the first time a microporous zeolitic imidazolate framework Co(dcIm)2 (TUT-100) with superhydrophobic properties for CH4/N2 separation. The CH4 adsorption capacity and CH4/N2 selectivity were as high as 45.29 cm3/cm3 and 6.3 (298 K, 1 bar), respectively, which results from the suitable SOD cage size (0.80 nm). The H2O adsorption was lower than 6.3 cm3/g at 298 K and near saturated pressure due to the hydrophobic group Cl. Breakthrough experiments were carried out to indicate the significant potential for CH4/N2 adsorption separation in a humid environment. The adsorption behavior of the gas mixture on the TUT-100 was investigated by the Grand Canonical Monte Carlo method and coupled with the experimental data. 相似文献
9.
Hailong Wang Neng Li Zhongbo Hu Thomas D. Bennett Xiujian Zhao Wai-Yim Ching 《Journal of the American Ceramic Society》2019,102(8):4602-4611
The amorphous zeolitic imidazolate frameworks (a-ZIFs) models and its analogues (with 918 or 810 atoms, respectively) are constructed based on a larger continuous random network (CRN) model of amorphous SiO2 (a-SiO2) model. The atomic, electronic, and dielectric properties of these structures, which possess different metal nodes and organic linkers, are investigated by well-defined density functional theory (DFT) calculations. The results suggest that all a-ZIFs have ultra-low dielectric constants and a large energy loss function (ELF), which suggests that they may be good candidates for electromagnetic absorptive materials. Most important, these a-ZIFs models offer a base-line model for other amorphous ZIFs for further research on models containing vacancies, defects, doping or under high pressure or high temperature. 相似文献
10.
《Catalysis communications》2007,8(5):789-794
An LTA membrane has been crystallized inside a porous ceramic tube and applied to synthesis of methanol from carbon dioxide and hydrogen in a zeolite membrane reactor (ZMR). The results obtained with the ZMR were compared with those gained from one traditional reactor (TR) used under the same operating conditions. CO2 conversion obtained with the ZMR at 210 °C reached 17% under conditions where the equilibrium value without zeolite membrane (TR) is equal to about 6%. 相似文献
11.
The design of polyimide-based pseudo-interpenetrating polymer networks (IPNs) is proposed to tailor the molecular structure of polymeric precursors for fabricating carbon molecular sieve membranes (CMSMs). To demonstrate the feasibility of this concept, pseudo-IPNs comprising of poly(2,3,5,6-phenylene-2,2′-bis(3,4-carboxylphenyl)hexafluoropropane) diimide (6FDA–TMPDA) and 2,6-bis(4-azidobenzylidene)-4-methylcyclohexanone (azide) are used to fabricate CMSMs. The gas transport properties of CMSMs are dependent on the azide loading and heat treatment temperature. During the pyrolysis, two competing processes of pore evolution from the released gases and molecular transformation are occurring simultaneously. The creation of pores determines the structural morphology of the CMSM at a low pyrolysis temperature of 550 °C while the molecular rearrangement is the governing factor for carbonization at an elevated temperature of 800 °C. The CMSMs prepared at 550 °C display good CO2/N2 separation performance. The 6FDA–TMPDA/azide (90–10) CMSM pyrolyzed at 550 °C shows a CO2 permeability of 9290 ± 170 Barrer and an ideal CO2/N2 selectivity of 26.0 ± 0.8. CMSMs with high CO2/CH4 selectivity can be fabricated by carbonization at 800 °C. The 6FDA–TMPDA/azide (70–30) CMSM prepared at 800 °C has a CO2 permeability of 280 ± 7.0 Barrer and CO2/CH4 selectivity of 164 ± 6.0. The CMSMs derived from polyimide/azide pseudo-IPNs exhibit potential use in pre- and post-combustion CO2 capture. 相似文献
12.
聚醚砜酮基炭膜的制备及其气体分离性能 总被引:1,自引:0,他引:1
采用浸渍涂膜法,以商用聚醚砜酮(PPESK)为前驱体制备了管式复合炭膜,考察了涂膜次数、改性剂及其加入量对所制备炭膜的气体分离性能的影响.结果表明,随着涂膜次数增多,气体分子的渗透速率逐渐减小而选择性呈增大趋势;加入改性剂后的复合炭膜渗透速率和分离系数均有不同程度的提高,表明改性剂不仅改善了涂膜液与支撑体之间的复合效果、减少涂膜次数,同时也促进了气体渗透速率的提高.利用扫描电镜对复合炭膜的微观形貌进行观测,可以看出,复合炭膜由支撑体和分离膜层2部分组成.膜表面很致密均匀,无明显缺陷,分离层薄而均一,厚度在5μm左右,且与支撑体结合紧密. 相似文献
13.
《Gas Separation & Purification》1993,7(3):147-149
The influence of different coating procedures on the transport and separation properties of composite gas separation membranes was studied. The composite membrane (CM) comprises a coating material (silicone rubber) in occluding contact with an asymmetric polysulfone flat membrane (AM). Permeabilities, ideal separation factors and structure of the CM were found to depend strongly on the evaporation time, volume and concentration of the coating solutions. Gas permeation experiments (H2, N2, CO2, CH4) indicated that gas permeabilities decreased rapidly with an increasing amount of coating. A maximum in the H2/N2, H2/CH4 ideal separation factor was reached as the amount of coating was increased. Scanning electron microscopy (SEM) studies revealed the presence of a dense isotropic layer of coating material above an anisotropic layer comprised of a mixture of polysulfone nodules and silicone material. The results showed that the CM prepared with a concentration of 6% silicone solution and contact time of 1 min has the best gas separation performance. 相似文献
14.
15.
A. V. Orlov S. G. Kiseleva G. P. Karpacheva V. V. Teplyakov D. A. Syrtsova L. E. Starannikova T. L. Lebedeva 《应用聚合物科学杂志》2003,89(5):1379-1384
Composite films based on the polyvinyltrimethylsilane (PVTMS) with polyaniline (PANI) coating were obtained by borderline polymerization of aniline. The obtained coating was shown to differ from the polymer forming in the reaction mixture bulk both in chemical structure and morphology. Ratio and concentration of the reagents, mixing rate, reaction time, and condition of support surface were among the investigated factors affecting the growth and quality of PANI coating. The gas separation characteristics of composite membranes, as affected by the process conditions and the type of PANI, were investigated. It is shown that the proposed method provides a means for obtaining composite membranes that combine high selectivity, especially in O2/N2, He/CH4, and CO2/CH4 separation, with permeability higher than that of known composite materials. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1379–1384, 2003 相似文献
16.
This work describes the enhanced mechanical properties of composite polydimethylsiloxane/poly(methyl methacrylate) (PDMS/PMMA)/multi-walled carbon nanotubes (MWCNTs) nanofiber membrane and its application in the phenol separation from saline wastewater. MWNCTs with varied content were immobilized in the membrane matrix using electric field of electrospinning. The neat PDMS/PMMA and composite PDMS/PMMA/MWCNTs membranes were characterized by scanning electron microscopy, universal testing machine, contact angle measurement, 3D automatic optical profiler, and pore size analyzer. Results indicated that tensile strength of composite PDMS/PMMA/MWNCTs membrane was drastically increased six times with a water contact angle (WCA) of 163.3° due to increased roughness parameters compared to neat membrane. However, porosity and fiber diameter of PDMS/PMMA/MWCTs membrane decreased with the increase of MWCNTs content. Moreover, phenol extraction efficiency of PDMS/PMMA/MWNCTs membrane was found to be 34.5% higher than neat one with similar salt rejection efficiency of 99.97%. The stability of MWCNTs in the membrane matrix was confirmed by the cross-sectional morphology, which indicated the robust and novel design of membrane. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47123. 相似文献
17.
Carbon molecular sieve membranes for gas separation prepared using poly(phenylene oxide) (PPO) as precursor have been examined. The PPO precursor was modified by introducing a trimethylsilyl (TMS) substituent and its effect on the gas transport property of the resulting carbon membrane was examined. TMS-substituted PPO (TMSPPO) was prepared in a high yield by a simple one-step reaction, and its carbon membrane was successfully fabricated. The modification improved the gas permeability of the resulting membrane which also exhibited excellent O2/N2 and CO2/CH4 separation performance comparable to those of polyimide-derived carbon membranes. From the analysis of the microstructure of the TMSPPO carbon membranes, it is believed that the TMS groups improve gas diffusivity by increasing the micropore volume. 相似文献
18.
Weisheng Yu Kaiyu Zhang Jianjun Zhang Xian Liang Xiaolin Ge Zijuan Ge Chengpeng Wei Wanjie Song Tongwen Xu Liang Wu 《American Institute of Chemical Engineers》2022,68(8):e17731
Precise control over the micromorphology of polyelectrolytes is the primary step toward understanding the structure–morphology–property relationships, ultimately determining the mass transfer characteristics. We report a novel polyolefin-scaffolded proton-exchange membrane (PEM) with the sectional installation of dipole–dipole interactions for this task. Experimental and theoretical investigations demonstrate that such noncovalent interactions drive the desired aggregation of ionic chains to form the hydrated two-dimensional (2D) ionic nanochannels. Micromorphology studies visualize the resultant lamellar topological morphology consisting of orderly arranged hydrophilic ionic and nonionic nanophases. The resulting membrane exhibits excellent proton conductivity (176–273 mS cm−1 at the temperature ranges from 30°C to 80°C) and H2/O2 fuel cell performance (especially at the lower relative humidity, the maximum power density is doubled that of commercial Nafion 212 at 40% relative humidity). Overall, we developed a promising design of the polyelectrolyte microstructure precise regulation for efficient ion conduction. 相似文献
19.
Mahdi Niknam Shahrak Morteza Niknam Shahrak Akbar Shahsavand Nasser Khazeni Xiaofei Wu Shuguang Deng 《中国化学工程学报》2017,25(5):595-601
Reliable estimation of the pore size distribution(PSD) in porous materials such as metal–organic frameworks(MOFs) and zeolitic imidazolate frameworks(ZIFs) is crucial for accurately assessing adsorption capacity and corresponding selectivity. In this study, the so-called zeolitic imidazolate framework-7(ZIF-7) is successfully synthesized via relatively fast and convenient microwave technique. The morphology and structure of the obtained MOF were characterized by XRD, SEM and N_2 and CO_2adsorption/desorption isotherms at 77 K and0 °C respectively. Then, to determine the PSD of the fabricated MOF, carbon dioxide isotherms are experimentally measured at various temperatures up to atmospheric pressure. Afterward, the experimental CO_2 isotherms data are utilized in two recently proposed in-house algorithms of SHN1 and SHN2 to extract the true PSD of manufactured ZIF-7. The obtained results revealed that median pore diameter of the fabricated ZIF-7 is estimated around 0.404 nm and 0.370 nm by using CO_2 isotherms at 273 K and 298 K respectively. These values are in good agreement with the real pore diameter of 0.42 nm. Moreover, experimental data of water adsorption isotherms over four different MOFs, borrowed from literature, are employed to illustrate further effectiveness of the above algorithms on successful determination of the corresponding pore size distributions. All predicted PSDs are proved to be in good agreement with those obtained from independent methods such as topology and morphology studies. 相似文献
20.
Mirzaei Ahmad Navarchian Amir H. Tangestaninejad Shahram 《Iranian Polymer Journal》2020,29(6):479-491
Iranian Polymer Journal - Gas separation membranes with enhanced performance were developed by the introduction of nanosized palladium particles. In this study, gas separation performance of... 相似文献