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1.
CO2-selective Pebax/NaY mixed matrix membranes (MMMs) were prepared by incorporating NaY zeolite into Pebax matrix. The morphology, chemical groups, thermal stability, and microstructure of the MMMs were investigated by scanning electron microscope, Fourier transform infrared spectroscopy, thermogravimetric analysis, and X-ray diffraction, respectively. The effects of zeolite loading amount, permeation temperature and pressure on the CO2/N2 separation performance of the resultant membranes were studied. The as-prepared MMMs are much superior to the pristine Pebax membranes in terms of permeability and selectivity. The CO2 permeability and CO2/N2 selectivity can respectively reach to 131.8 Barrer and 130.8 for MMMs made by the starting materials containing 40 wt % NaY. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48398.  相似文献   

2.
The present study deals with preparing mixed matrix membranes (MMMs), a new polysaccharide-based natural polymer used as a matrix with functionalized carbon nanotubes (FCNTs) and graphene oxide (GO) used as an inorganic filler. This work identified the effect of the inorganic fillers (FCNTs or GO) with naturally occurring polymer for gas separation. The incorporation of fillers improves the gas separation performance of MMMs. In GG/FCNTs MMMs, the selectivities of CO2/N2 and CO2/H2 were enhanced by 55.24% and 57.89%, respectively. Moreover, in GG/GO MMMs, the selectivities of CO2/N2 and CO2/H2 were improved by 99.50% and 50%, respectively. The membrane was characterized by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The SEM analysis of GG/GO MMMs reveals layered structure, and GG/FCNTs MMMs create passages to transport gases. The Universal testing machine (UTM) is used to analyze the mechanical properties of pristine and modified membranes.  相似文献   

3.
Novel facilitated‐transport mixed‐matrix membrane (MMM) were prepared through the incorporation of polydopamine (PDA) microspheres into a poly(amide‐b‐ethylene oxide) (Pebax MH 1657) matrix to separate CO2–CH4 gas mixtures. The Pebax–PDA microsphere MMMs were characterized by Fourier transform infrared spectroscopy, scanning electron microcopy, X‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The PDA microspheres acted as an adhesive filler and generated strong interfacial interactions with the polymer matrix; this generated a polymer chain rigidification region near the polymer–filler interface. Polymer chain rigidification usually results in a larger resistance to the transport of gas with a larger molecular diameter and a higher CO2–CH4 selectivity. In addition, the surface of PDA microspheres contained larger numbers of amine, imine, and catechol groups; these were beneficial to the improvement of the CO2 separation performance. Compared with the pristine Pebax membrane, the MMM with a 5 wt % PDA microsphere loading displayed a higher gas permeability and selectivity; their CO2 permeability and CO2–CH4 selectivity were increased by 61 and 60%, respectively, and surpassed the 2008 Robeson upper bound line. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44564.  相似文献   

4.
In the present study, graphene oxide (GO) was incorporated into poly(vinylidene fluoride) (PVDF) and chemically modified PVDF (M‐PVDF) to prepare mixed matrix membranes (MMMs) for gas separation application. Performed analyses proved appropriate dispersion of exfoliated GO sheets in polymer matrices and sufficient compatibility at the interfacial phases. M‐PVDF based MMMs were thermally and mechanically more stable relative to the PVDF‐based MMMs. The oxygen containing functional groups in M‐PVDF was probably the main reason for this more stability. PVDF/GO MMMs rendered low gas permeability and high selectivity. Both impermeable GO sheets and crystalline phases of PVDF were responsible for such behavior. On the other hand, interestingly gas permeability of M‐PVDF/GO MMMs was enhanced while no substantial decline was recorded in gas selectivity. For instance, He and CO2 permeability was increased 12.46% and 25.89%, respectively, compared to the pure PVDF membrane. This behavior originated from functional groups of M‐PVDF and the interaction of these groups with GO sheets. Since GO often amplified gas barrier properties of polymers, such increscent would be appreciable. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46271.  相似文献   

5.
In order to facilitate CO2 transport in Pebax-based membranes, graphene oxide (GO)/core shell ZIF-8@ZIF-67 nanocomposites were loaded in Pebax copolymer to improve CO2 permeability and selectivity. The 0.5 wt% GO doped core shell ZIF-8@ZIF-67, which gave highest CO2 adsorption capacity of 1.12 mmol/g, was used as nanocomposite. The incorporated GO/core shell ZIF enhanced CO2 adsorption via unsaturated metal sites (Zn-O or Co-O), because O atoms in GO substituted for N atoms coordinated with Zn and Co single atoms in core shell ZIF-8@ZIF-67. Positron annihilation lifetime spectroscopy indicated that GO-templated core shell ZIF nanocomposites generated extra free volume and provided low-resistance channels to facilitate CO2 transport. Fourier transform infrared spectroscopy analysis revealed that hydrogen bonds were generated between Pebax polymer chains and GO-templated core shell ZIF which improved swelling resistance and reduced interface defects. Therefore, Pebax-based MMMs loaded with 5 wt% GO/core shell ZIF-8@ZIF-67 exhibited optimum CO2 permeability (173.2 barrers) and ideal selectivity of CO2/N2 (61.9) and CO2/H2 (11.6), which were 99.7%, 66.4%, and 20.8% higher than Pebax membranes and surpass Robeson 2008 upper bound. The tensile strength increased by 17.6% to 28.8 MPa and elongation at break increased by 7.61%–554.6% when pure Pebax membranes were incorporated with 2.5 wt% GO/core shell ZIF-8@ZIF-67.  相似文献   

6.
Modified ultra-porous ZIF-8 particles were used to prepare novel ZIF-8/Pebax 1657 mixed matrix membranes (MMMs) on PES support for separation of CO2 from CH4 using spin coating method. TEM and SEM were used to characterize modified ZIF-8 particles. SEM was also used to investigate the morphology of synthesized MMMs. The MMMs with thinner selective layer showed higher CO2 permeability and lower CO2/CH4 selectivity in permeation tests compared to MMMs with thicker selective layer. The plasticization was recognized as the main reason for rise in CO2 permeability and drop in CO2/CH4 selectivity of thinner MMMs. The gas sorption results showed that the high permeability of CO2 in MMMs is mainly due to the high solubility of this gas in MMMs, leading to high CO2/CH4 solubility selectivity for MMMs. The fractional free volume and void volume fraction of MMMs increased as the thickness of membrane decreased. Applying higher mixed feed pressures and permeation tests temperatures resulted in increase in CO2 permeability and decrease in CO2/CH4 selectivity. At highest testing temperature (60 °C), the CO2 permeability of synthesized MMMs with thinner selective layer remarkably increased.  相似文献   

7.
With MOFs of Cu3(BTC)2 and ZIF‐8 as the dispersed phases and four polyimides with CO2 permeabilities ranging from 1.36 to 564 barrer as the continuous phase, the influence of metal organic frameworks on the gas‐separation properties of mixed‐matrix membranes (MMMs) was investigated. The results show that the gas permeabilities of all of the prepared MMMs greatly increased and even largely exceeded the predicted value of the Bruggeman model; for example, with the same Cu3(BTC)2 loading of 21.3 vol %, the O2 permeability increase rate of our prepared Cu3(BTC)2/Matrimide 5218‐20 MMMs was 2.26 times, whereas that predicted by the Bruggeman model was only 1.05 times. In addition, when the gas permeability of the polymeric phase was far lower than the dispersed phase of ZIF‐8 or Cu3(BTC)2 compared with ZIF‐8, which had a particle size (R) around 150 nm, Cu3(BTC)2 of 5–15 µm showed a little better enhancing effect on the gas‐permeation performance of the MMMs. In addition to the properties of the dispersed and continuous phases, we speculated that the ratio between R of the dispersed phase to the membrane thickness (L) played an important role for MMMs; the larger R/L was, the greater the gas permeability of the MMMs was. This speculation was initially evidenced by the ZIF‐8/ODPA/TMPDA‐20 MMMs with different Ls. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45728.  相似文献   

8.
Graphene oxide (GO)‐polyether block amide (PEBA) mixed matrix membranes were fabricated and the effects of GO lateral size on membranes morphologies, microstructures, physicochemical properties, and gas separation performances were systematically investigated. By varying the GO lateral sizes (100–200 nm, 1–2 μm, and 5–10 μm), the polymer chains mobility, as well as the length of the gas channels could be effectively manipulated. Among the as‐prepared membranes, a GO‐PEBA mixed matrix membrane (GO‐M‐PEBA) containing 0.1 wt % medium‐lateral sized (1–2 μm) GO sheets showed the highest CO2 permeation performance (CO2 permeability of 110 Barrer and CO2/N2 mixed gas selectivity of 80), which transcends the Robeson upper bound. Also, this GO‐PEBA mixed matrix membrane exhibited high stability during long‐term operation testing. Optimized by GO lateral size, the developed GO‐PEBA mixed matrix membrane shows promising potential for industrial implementation of efficient CO2 capture. © 2016 American Institute of Chemical Engineers AIChE J, 62: 2843–2852, 2016  相似文献   

9.
A series of poly(amide‐co‐poly(propylene glycol)) (PA‐PPG) random copolymers with different content of PPG were designed by polycondensation reaction. These random copolymers were blended up to 60% with commercially available Pebax 2533. The blend membranes were characterized by Fourier‐transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscope (SEM). Gas permeation properties of these blend membranes were investigated using five single‐gases (CO2, H2, O2, CH4, and N2) at different temperature of 25–55°C and 1.0 atm. The impacts of content of PA‐PPG with different PPG content and operating temperature on CO2 separation properties of Pebax/PA‐PPG blend membranes were studied. The results showed that CO2 permeability gradually increased with the increasing operating temperature, whereas CO2 permeability gradually decreased with the increase in content of PA‐PPG. CO2/N2 selectivity gradually increased with the increase in content of PA‐PPG. In particular, Pebax/PA‐PPG (50)–60% displayed excellent CO2 and O2 separation properties (PCO2 = 79.7 Barrer and PO2 = 13.6 Barrer, CO2/N= 34.7 and O2/N= 5.9) at 25°C and 1.0 atm. POLYM. ENG. SCI., 59:E14–E23, 2019. © 2018 Society of Plastics Engineers  相似文献   

10.
This study investigated the effect of annealing time and temperature on gas separation performance of mixed matrix membranes (MMMs) prepared from polyethersulfone (PES), SAPO‐34, and 2‐hydroxy 5‐methyl aniline (HMA). A postannealing period at 120°C for a week extensively increased the reproducibility and stability of MMMs, but for pure PES membranes no post‐annealing was necessary for stable and reproducible performance. The effect of operation temperature was also investigated. The permeabilities of H2, CO2, and CH4 increased with increasing permeation temperature from 35°C to 120°C, yet CO2/CH4 and H2/CH4 selectivities decreased. PES/SAPO‐34/HMA ternary and PES/SAPO‐34 binary MMMs exhibited the highest ideal selectivity and permeability values at all temperatures, respectively. For H2/CO2 pair, when temperature increased from 35°C to 120°C, selectivity increased from 3.2 to 4.6 and H2 permeability increased from 8 to 26.5 Barrer for ternary MMM, demonstrating the advantage of using this membrane at high temperatures. The activation energies were in the order of CH4 > H2 > CO2 for all membranes. PES/SAPO‐34/HMA membrane had activation energies higher than that of PES/SAPO‐34 membrane, suggesting that HMA acts as a compatibilizer between the two phases. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40679.  相似文献   

11.
In this study, mixed matrix membranes (MMMs) were prepared using commercially available poly(ether‐b‐amide) (Pebax2533) as polymer matrix and organically modified montmorillonite (OMMt) as filler with the aim of investigating their gas permeation properties. The prepared membranes were characterized by Fourier‐transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscope (SEM), thermal gravimetric analysis, and tensile strength analyses. Gas permeation properties of all the prepared membranes were evaluated at different pressures and clay loadings. Results of FTIR and SEM confirmed the appropriate adhesion between polymer and nanoclays so that no void formation was observed in the polymer/clay interface. XRD results showed that in low loading, clay dispersion occurred as exfoliated‐intercalated and at high loading as intercalated‐phase separated. Results of gas permeation test showed that by adding layered and impermeable clay particles to the polymer matrix, the permeation of soluble CO2 gas reduced by 28% for the highest clay loading. By increasing of pressure from 2 to 6 bar, CO2/CH4 permselectivity increased at all nanoclay loadings. The highest CO2/CH4 selectivity was obtained for 6 wt % clay MMM at all pressures, while the highest CO2/H2 selectivity was achieved for neat polymer at 6 bar. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45302.  相似文献   

12.
The packing pattern of two-dimensional (2D) sheet-like fillers in membranes is relatively random, leading to the unfavorable permeability from tortuous diffusion pathway. A new strategy that using prestructured materials with uniform channels as fillers was proposed. In this work, Ti3AlC2 is etched to prepare multilayered MXene (m-MXene), the channels aggregate as a whole unit, ensure the impossibility of ineffective packing compared with traditional individual sheets, largely facilitating the selective permeation. Then, the m-MXene/Poly (amide-6-b-ethylene oxide) (Pebax) MMMs are synthesized. SEM images demonstrate the accordion shaped structure of filler, which is the multi-channels laminates. Furthermore, the results of gas permeation test exhibit enhanced performance of m-MXene/Pebax MMMs. MMM with 0.5 wt.% m-MXene behaved best, CO2 permeability of 86.22 Barrer as well as CO2/N2 selectivity of 104.85, transcending the Robeson upper bound (2008). Having distinct enhancement for CO2 separation, the m-MXene/Pebax MMMs in this work offer prospective practical applications.  相似文献   

13.
《Polymer Composites》2017,38(7):1363-1370
Mixed matrix membranes offer major advantages in gas separation processes due to desirable properties found in both organic and inorganic membranes. In this study, a novel mixed matrix membrane was prepared for such application by incorporating iron benzene‐1,3,5‐tricarboxylate (Fe‐BTC) into the poly(amide‐6‐b‐ethylene oxide) (Pebax1657) polymer. Membranes with various loadings of 5, 10, and 20 wt% Fe‐BTC in the polymer matrix were fabricated to investigate the effect of filler loading on the membrane performance. Membranes, prepared by solution‐casting were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared, X‐ray diffraction, and tensile test. Pure gas separation of CO2, CH4, and N2 and ideal gas selectivity of CO2/CH4 and CO2/N2 were performed and permeation tests were carried out under 4, 8, and 12 bar pressures. Results show that adding Fe‐BTC into the Pebax1657 matrix improved both permeability and selectivity of the filled membranes. For instance, 10 wt% loading of Fe‐BTC into the Pebax1657 matrix led to CO2 permeability increase of 49% as well as CO2/CH4 and CO2/N2 selectivities enhancements of about 36% and 16%, respectively. POLYM. COMPOS., 38:1363–1370, 2017. © 2015 Society of Plastics Engineers  相似文献   

14.
Enhancing the performance of gas separation membranes is one of the major concerns of membrane researchers. Thus, in this study, poly(ether-block-amide) (Pebax)/polyetherimide (PEI) thin-film composite membranes were prepared and their CO2/CH4 gas separation performance was investigated by means of pure and mixed gases permeation tests. To improve the properties of these membranes, halloysite nanotubes (HNT) were added to Pebax layer at different loadings of 0.5, 1, 2, and 5 wt % to form Pebax-HNT/PEI membranes. Scanning electron microscopy, gas sorption, X-ray diffraction, Fourier-transform infrared, and differential scanning calorimetry tests were also performed to investigate the impact of HNT on structure and properties of prepared membranes. Results showed that both CO2/CH4 selectivity and CO2 permeance increased by adding HNT to Pebax layer up to 2 wt %. By increasing HNT loading to 5 wt %, the CO2/CH4 selectivity decreased from 32 to 18, while CO2 permeance increased from 3.25 to 4.2 GPU. Pebax/PEI and Pebax-HNT/PEI membranes containing 2 wt % of HNT were tested using CO2/CH4 gas mixtures at different feed CO2 concentrations and feed pressure of 4 bar. The results showed that with increasing CO2 concentration from 20 to 80 vol %, CO2/CH4 selectivity of Pebax/PEI composite membranes increased by 19%, while, in Pebax-HNT/PEI membrane, CO2/CH4 selectivity decreased by 40%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48860.  相似文献   

15.
Poly(N‐vinyl‐γ‐sodium aminobutyrate‐co‐sodium acrylate) (VSA–SA)/polysulfone (PS) composite membranes were prepared for the separation of CO2. VSA–SA contained secondary amines and carboxylate ions that could act as carriers for CO2. At 20°C and 1.06 atm of feed pressure, a VSA–SA/PS composite membrane displayed a pure CO2 permeation rate of 6.12 × 10?6 cm3(STP)/cm2 s cmHg and a CO2/CH4 ideal selectivity of 524.5. In experiments with a mixed gas of 50 vol % CO2 and 50 vol % CH4, at 20°C and 1.04 atm of feed pressure, the CO2 permeation rate was 9.2 × 10?6 cm3 (STP)/cm2 s cmHg, and the selectivity of CO2/CH4 was 46.8. Crosslinkages with metal ions were effective for increasing the selectivity. Both the selectivity of CO2 over CH4 and the CO2 permeation rate had a maximum against the carrier concentration. The high CO2 permeation rate originated from the facilitated transport mechanism, which was confirmed by Fourier transform infrared with attenuated total reflectance techniques. The performance of the membranes prepared in this work had good stability. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 275–282, 2006  相似文献   

16.
The application of thin‐film composite mixed‐matrix membranes (TFC‐MMMs) for gas separation is widely considered as an efficient separation technology. The principal methods for the preparation of TFC‐MMMs are dip‐coating, phase inversion, and interfacial polymerization comprising different types of support layers. These methods influence the CO2 permeation over the selective and support layers. A comprehensive review is provided for capturing new details of progress achieved in developing TFC‐MMMs with detailed performance of gas separation in the previous few years. Various preparation techniques of TFC‐MMMs and their effect on the gas separation performance of the prepared membranes are described.  相似文献   

17.
Nowadays, mixed matrix membranes (MMMs) have considered by many researchers to overcome the problems of polymeric membranes. In addition, molecular dynamics (MD) and Monte Carlo (MC) simulation Methods are suitable tools for studying transport properties and morphology in MMMs. For this purpose, in this study using material studio 2017 (MS) software, the transport properties of CO2, CH4 and N2 in Pebax, Psf neat Pebax/Psf composite and Pebax/Psf composite filled with ZIF-90 particles have been investigated. By adding Psf to Pebax matrix, the selectivity of CO2/CH4 and CO2/N2 gases has significantly increased. In addition, adding ZIF-90 particles to the Pebax/Psf composite increased the permeability of CO2, CH4 and N2 compared to neat and composite membranes. The morphological properties of the membranes, such as the fractional free volume (FFV), radial distribution function (RDF), glass transition temperature (TG), X-ray diffraction (XRD) and equilibrium density have calculated and acceptable results have obtained.  相似文献   

18.
In this work, hydrogen (H2) permeation fluxes through 230 nm‐thick graphene oxide (GO) membrane deposited on porous YSZ hollow fiber were measured and correlated to an explicit H2 permeation model. H2 fluxes through such GO‐YSZ hollow fiber membrane increased from 4.83 × 10?8 mol cm?2 s?1 to 2.11 × 10?7 mol cm?2 s?1 with temperature rise from 20 to 100 °C. The activation energy of H2 permeation was determined by the linear regression of the experimental data and was applied in the theoretical calculations. The model predictions fit well the temperature dependent and the argon sweep gas flow rate dependent H2 fluxes data. Using the derived permeation model, the effects of vacuum pressure at lumen side and H2 partial pressure at shell side, membrane area, and GO membrane film thickness on the membrane performance were simulated and discussed to provide insights for practical applications. © 2018 American Institute of Chemical Engineers AIChE J, 64: 2711–2720, 2018  相似文献   

19.
To construct rapid C3H8 transport pathways in polymer matrix, alkyl chain‐functionalized graphene oxide (GO) was prepared via grafting octadecylamine (ODA) molecules and then embedded into polydimethylsiloxane (PDMS) matrix to obtain high‐efficiency mixed matrix membranes (MMMs). The incorporation of alkyl chains contributes to lowering the surface energy of GO nanosheets and providing higher affinity with PDMS matrix. Additionally, the alkyl chains on the surface of ODA‐functionalized GO nanosheets (ODA‐GO) are in favor of C3H8 adsorption, thus conferring continuous and specific transport pathways for C3H8. The optimized membrane with ODA‐GO loading of 0.3 wt% exhibits the C3H8 permeance of 1897 GPU and the C3H8/N2 ideal selectivity of 67, which are 50.2 and 72.5% higher than those of bare PDMS membrane, respectively. The simultaneous enhancement of C3H8 permeance and C3H8/N2 ideal selectivity indicates that ODA‐GO is an effective filler applied in MMMs for C3H8 recovery. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3501–3510, 2017  相似文献   

20.
Poly(l ‐lactic acid) (PLLA) ‐ 20% (w/w) and Cu3(BTC)2 metal organic framework (MOF) based mixed matrix membranes (MMMs) were fabricated by a vertical corotating twin screw microcompounder followed by an injection molding process. Water vapor, CO2, O2, and selected aroma mass transfer properties of PLLA and PLLA MMMs were evaluated. The CO2/O2 perm‐selectivity of PLLA (αCO2/O2) MMMs increased from 7.6 to 10.3 with the incorporation of 20% Cu3(BTC)2 MOF. Gravimetric permeability studies of trans‐2‐hexenal performed at 23°C and 50% RH indicated that permeability coefficient of PLLA MMMs increased by around 60% as compared to regular PLLA film. However, no changes in mass transfer rates were observed for acetaldehyde. Furthermore, the thermal processing parameters as well as the presence of MOF did not show any significant effect on the molecular weight of the PLLA matrix nor on the crystalline structure of the Cu3(BTC)2 MOF, which was confirmed by both gel permeation chromatography and X‐ray diffraction studies. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42764.  相似文献   

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