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1.
Several sulfolanes such as 3-methylsulfolane, sulfolane, and 3-sulfolene were tested as modifiers in poly(trimethylsilyl methyl methacrylate) (PTMSMMA) and poly(trimethylsilyl propyne) (PMSP) to improve the selectivity of CO2. The gas permeabilities for the PTMSMMA-blend membranes containing high 3-methylsulfolane content were determined on a nonvacuum system in which the membranes started to be measured at their steady states at 30°C; those for all the other membranes were determined in a vacuum system in which those membranes were measured after they reached their unsteady states at 30°C. The PTMSMMA-blend membrane containing 40% 3-methylsulfolane was found to give the best separation of CO2 under the conditions in this study compared to all the PTMSMMA-blend membranes and the others prepared in our work; its ideal separation factors for CO2 over N2 were above 40 and its permeability coefficients of CO2 increased to above 250 Barrer. The modifications of PMSP membranes by impregnating with sulfolane and blending with sulfolene were found to be effective in improving the selectivity for CO2 over N2 for the PMSP membrane. The ideal separation factors for CO2 over N2 for the modified PMSP membranes impregnated with 30% sulfolane and blended with 25% 3-sulfolene were improved to above 10 and 13, respectively. © 1996 John Wiley & Sons, Inc.  相似文献   

2.
Minor components present in polymeric membrane gas separation can have a significant influence on the separation performance. Carbon monoxide and nitric oxide exist in post-combustion gas streams and can therefore influence CO2 transport through membranes designed for that application. Here, the permeability of nitric oxide (NO) through three glassy polymeric membranes (polysulfone, Matrimid 5218 and 6FDA-TMPDA) was determined and found to be less than the CO2 but greater than the N2 permeability in each membrane. This study also investigated the influence of 1000 ppm CO on the mixed gas permeability of CO2 and N2 for two glassy polymeric membranes; polysulfone and 6FDA-TMPDA. For both membranes, CO competitive sorption resulted in a reduction in the measured permeability of CO2 and N2 even though present at only low concentration.  相似文献   

3.
Physical and gas transport properties of hyperbranched polyimide-silica hybrid membranes were investigated. Hyperbranched polyamic acid as a precursor was prepared by polycondensation of a triamine, 1,3,5-tris(4-aminophenoxy) benzene (TAPOB), and a dianhydride, 4,4′-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), and subsequently modified a part of end groups by 3-aminopropyltrimethoxysilane (APTrMOS). The hyperbranched polyimide-silica hybrid membranes were prepared by sol–gel reaction using the polyamic acid, water, and alkoxysilanes. 5% weight-loss temperature of the hybrid membranes increased with increasing silica content, indicating effective crosslinking at polymer-silica interface mediated by APTrMOS moiety. On the other hand, glass transition temperature of the hybrid membranes prepared with methyltrimethoxysilane (MTMS) showed a minimum value at low silica content region, suggesting insufficient formation of three-dimensional Si O Si network compared to the hybrid membranes prepared with tetramethoxysilane (TMOS). CO2, O2, N2, and CH4 permeability coefficients of the hybrid membranes increased with increasing silica content. Especially for TMOS/MTMS combined system, the hybrid membranes showed simultaneous enhancements of gas permeability and CO2/CH4 separation ability. It was concluded that the 6FDA-TAPOB hyperbranched polyimide-silica hybrid membranes have high thermal stability and excellent CO2/CH4 selectivity and are expected to apply to high-performance gas separation membranes. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008  相似文献   

4.
The development of carbon dioxide (CO2) separation technology is crucial for mitigating global climate change and promoting sustainable development. In this study, we successfully synthesized an array of cross-linked poly(vinyl alcohol) (PVA) membranes, xALD-PEG-ALD-c-PVA, with enhanced CO2/N2 separation performance by employing dialdehyde polyethylene glycol (ALD-PEG-ALD) as a cross-linker. The formation of the cross-linked network structure not only inhibits the crystallization of PVA but also disrupts hydrogen bonding and thus increases fractional free volume of PVA chains. Under the synergistic effect of these multiple factors, the cross-linked PVA membranes exhibit a significantly improved CO2 permeability. Moreover, they maintain high CO2/N2 selectivity, attributing to the CO2-philic characteristic of ethylene oxide groups in the cross-linked structure. At the ALD-PEG-ALD content of 1.6 mmol g−1, the xALD-PEG-ALD-c-PVA membrane demonstrates a CO2 permeability of 41.4 barrer and a CO2/N2 selectivity of 57.4 at 2 bar and 25°C. Furthermore, compared with the pristine PVA membrane, xALD-PEG-ALD-c-PVA membranes manifest superior mechanical properties and outstanding separation performance for a CO2/N2 (15/85, vol%) gas mixture. The excellent combination of permeability and selectivity makes xALD-PEG-ALD-c-PVA membranes highly promising for various CO2 separation applications.  相似文献   

5.
The gas permeation properties of H2, He, CO2, O2, and N2 through silicone-coated polyethersulfone (PESf) asymmetric hollow-fiber membranes with different structures were investigated as a function of pressure and temperature and compared with those of PESf dense membrane and silicone rubber (PDMS) membrane. The PESf asymmetric hollow-fiber membranes were prepared from spinning solutions containing N-methyl-2-pyrrolidone as a solvent, with ethanol, 1-propanol, or water as a nonsolvent-additive. Water was also used as both an internal and an external coagulant. A thin silicone rubber film was coated on the external surface of dried PESf hollow-fiber membranes. The apparent structure characteristics of the separation layer (thickness, porosity, and mean pore size) of the asymmetric membranes were determined by gas permeation method and their cross-section morphologies were examined with a scanning electron microscope. The results reveal that the gas pressure normalized fluxes of the five gases in the three silicone-coated PESf asymmetric membranes are nearly independent of pressure and did not exhibit the dual-mode behavior. The activation energies of permeation in the silicone-coated asymmetric membranes may be larger or smaller than those of PESf dense membrane, which is controlled by the membrane physical structure (skin layer and sublayer structure). Permselectivities for the gas pairs H2/N2, He/N2, CO2/N2, and O2/N2 are also presented and their temperature dependency addressed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 837–846, 1997  相似文献   

6.
C/CMS composite membranes derived from poly(furfuryl alcohol) (PFA) polymerized by iodine catalyst were prepared. Gas separation performance was investigated by molecular probe study with pure gases (H2, CO2, O2, N2, and CH4) at 25 °C. The pyrolysis behaviour of PFA was studied by TG and DTG. The surface morphology of C/CMS composite membranes was observed by SEM and HRTEM. The results show a C/CMS composite membrane with uniform and defect-free thin top layer can be prepared by the PFA liquid in only one coating step. The C/CMS composite membranes have excellent gas separation properties for the gas pairs such as H2/N2, CO2/N2, O2/N2 and CO2/CH4, the permselectivities for above gas pairs in same sequence were 124.72, 12.74, 9.12 and 15.91 respectively. Compared to carbon membranes derived from PFA polymerized by acid catalyst, the carbon membranes obtained from PFA polymerized by iodine catalyst have slightly lower permselectivity, but higher permeance.  相似文献   

7.
Summary Plasma-polymerized membranes for gas separation were prepared from 1-(trimethylsilyl)-1-propyne. The permeation data of He, H2 02, N2, CO2, and CH4 through the membranes showed plasma-polymerized 1-(trimethylsilyl)-1-propyne had high permselectivity but low permeability compared with poly[l-(trimethylsilyl)-1-propyne]. This behavior is considered to be due to the crosslinking structure of the plasma-polymerized membrane. The correlation between plasma polymerization conditions and the membrane performance was studied. The optimum condition at which the deposition rate of the plasma polymer is maximized agreed with the optimum value to yield maximum separation factor of gases through the membrane.  相似文献   

8.
Cellulose acetate (CA) is well known glassy polymer used in the fabrication of gas‐separation membranes. In this study, 5,11,17,23‐tetrakis(N‐morpholinomethyl)‐25,26,27,28‐tetrahydroxycalix[4]arene (CL) was blended with CA to study the gas‐permeation behavior for CO2, N2, and CH4 gases. We prepared the pure CA and CA/CL blended membranes by following a diffusion‐induced phase‐separation method. Three different concentrations of CL (3, 10, and 30 wt %) were selected for membrane preparation. The CA/CL blended membranes were then characterized via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and X‐ray diffraction analysis. The homogeneous blending of CL and CA was confirmed in the CA/CL blended membranes by both SEM and AFM analysis. In addition to this, the surface roughness of the CA/CL blended membranes also increased with increasing CL concentration. FTIR analysis described the structural modification in the CA polymer after it was blended with CL too. Furthermore, CL improved the tensile strength of the CA membrane appreciably from 0.160 to 1.28 MPa, but this trend was not linear with the increase in the CL concentration. CO2, CH4, and N2 gases were used for gas‐permeation experiments at 4 bars. With the permeation experiments, we concluded that permeability of N2 was higher in comparison to those of CO2 and CH4 through the CA/CL blended membranes. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39985.  相似文献   

9.
The development of desirable chemical structures and properties in nanocomposite membranes involve steps that need to be carefully designed and controlled. This study investigates the effect of adding multiwalled nanotubes (MWNT) on a Kapton–polysulfone composite membrane on the separation of various gas pairs. Data from Fourier transform infrared spectroscopy and scanning electron microscopy confirm that some studies on the Kapton–polysulfone blends are miscible on the molecular level. In fact, the results indicate that the chemical structure of the blend components, the Kapton–polysulfone blend compositions, and the carbon nanotubes play important roles in the transport properties of the resulting membranes. The results of gas permeability tests for the synthesized membranes specify that using a higher percentage of polysulfone (PSF) in blends resulted in membranes with higher ideal selectivity and permeability. Although the addition of nanotubes can increase the permeability of gases, it decreases gas pair selectivity. Furthermore, these outcomes suggest that Kapton–PSF membranes with higher PSF are special candidates for CO2/CH4 separation compared to CO2/N2 and O2/N2 separation. High CH4, CO2, N2, and O2 permeabilities of 0.35, 6.2, 0.34, and 1.15 bar, respectively, are obtained for the developed Kapton–PSF membranes (25/75%) with the highest percentage of carbon nanotubes (8%), whose values are the highest among all the resultant membranes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43839.  相似文献   

10.
The effects of NH3‐plasma and N2‐plasma treatment on rubbery polypropylene (PP) membrane upon permeation behavior for CO2, O2, and N2 were investigated from their permeability measurements. The NH3‐plasma and N2‐plasma treatment on PP membranes could increase both the permeability coefficient for CO2 and the ideal separation factor for CO2 relative to N2. For O2 transport, both the permeability coefficient for O2 and the ideal separation factor for O2 relative to N2 also increased. NH3‐plasma and N2‐plasma treatment on PP membranes possibly brings about an augmentation of permeability for CO2 and permselectivity of CO2 relative to N2 simultaneously, but unfortunately the plasma‐treated PP membrane does not reach the level of CO2 separation membrane. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007  相似文献   

11.
Gas separation process is an effective method for capturing and removing CO2 from post-combustion flue gases. Due to their various essential properties such as ability to improve process efficiency, polymeric membranes are known to dominate the market. Trade-off between gas permeability and selectivity through membranes limits their separation performance. In this study, solution casting cum phase separation method was utilized to create polyethersulfone-based composite membranes doped with carbon nanotubes (CNTs) and silico aluminophosphate (SAPO-34) as nanofiller materials. Membrane properties were then examined by performing gas permeation test, chemical structural analysis and optical microscopy. While enhancing membranes CO2 permeance, SAPO-34 and CNTs mixture improved their CO2/N2 selectivity. By carefully adjusting membrane casting factors such as filler loadings. Using Taguchi statistical analysis, their carbon capture efficiency was improved. The improved mixed-matrix membrane with loading of 5 wt% CNTs and 10 wt% SAPO-34 in PES showed highly promising separation performance with a CO2 permeability of 319 Barrer and an ideal CO2/N2 selectivity of 12, both of which are within the 2008 Robeson upper bound. A better mixed-matrix membrane with outstanding CO2/N2 selectivity and CO2 permeability was produced as a result of the synergistic effect of adding two types of fillers in optimized loading.  相似文献   

12.
The present work reports the effect of various organically functionalized polyhedral oligomeric silsesquioxane (POSS) particles on the gas transport properties (N2, O2, and CO2 molecules) in poly(vinyl alcohol) (PVA) membranes. The incorporation of polyethylene glycol-POSS (PEG-POSS), octa-tetramethylammonium-POSS (Octa-TMA-POSS) and m-POSS (Octa-TMA-POSS molecule was modified using cetyltrimethyl ammonium bromide) led to the enhancement in CO2 separation performance of PVA, among which, PEG-POSS exhibited highest CO2 separation due to the dipole-quadrupolar interaction of CO2 with ethylene oxide group in POSS. Octa-TMA-POSS and m-POSS reduced the O2 and N2 permeability of the PVA membrane due to the reduction in the number of permeating pathways as compared to pure PVA. Free volume of the membranes was evaluated by positron annihilation lifetime spectroscopic (PALS) and coincidence Doppler broadening measurements. PALS confirms the increase in polymer free volume in PVA/POSS system due to the presence of rigid and spherical POSS molecule, which could enter in the polymer chain and provide viable pathway for molecular transport. Maxwel–Wagner–Sillar and Higuchi models were applied for the theoretical prediction of permeability of the fabricated membranes.  相似文献   

13.
Gas transport through interfacially formed poly(N,N-dimethylaminoethyl methacrylate) membranes was investigated. The membrane performance for the separation of binary CO2/N2, CO2/CH4 and CO2/H2 mixtures was studied, and the coupling effects between the permeating species were evaluated by comparing the permeance of individual components in the mixture with their pure gas permeance. For the permeation of these binary gas mixtures, the presence of CO2 was shown to influence the permeation of the other components (i.e., N2, H2 and CH4), whereas the permeation of CO2 was not affected by these components. In consideration that water vapor is often encountered in applications involving CO2 separation, the presence of water vapor on the membrane permselectivity was also studied. When hydrated, the membrane was shown to be more permeable to CO2, while the membrane selectivity did not change significantly. Unlike membranes based on size-sieving of penetrant molecules, the present membranes exploit the favorable interactions between the hydrophilic quaternary amines in the membrane and CO2, especially in the presence of water vapor in the feed.  相似文献   

14.
Membranes obtained from polymers, quaternized poly[3-(N′,N′-dimethyl) aminopropylacrylamide-co-acrylonitrile]s, showed selective separation of water from aqueous ethanol solution by pervaporation. The separation factor toward water reached over 15,000. Membrane performance showed a good correlation to membrane polarity. Differential scanning calorimetric melting endotherms of the water-swollen membranes were studied to clarify the state of water in the membranes. The results suggested that there are two states of water in the membrane: bound and free. The higher the fraction of bound water in the membrane, clearly, the more preferentially was water permeated.  相似文献   

15.
Asymmetric polysulfone (PSF) gas separation membranes were prepared at different conditions such as non‐solvent concentration, evaporation time (ET) and coagulation bath temperature (CBT). In addition, effects of low‐pressure DC glow discharge plasma on the characteristics of PSF membranes were investigated. PSF membranes both before and after plasma treatment were characterized by several techniques, including contact angle measurement, scanning electron microscope (SEM), dynamic mechanical thermal analysis (DMTA), and atomic force microscopy (AFM). Furthermore, the performance of membranes was evaluated in terms of permeability of CO2, CH4, O2, and N2 gases. The ideal selectivity of CO2/CH4 and O2/N2 and surface free energy was calculated. Results showed that the EtOH concentration, ET and CBT affect the morphology of PSF membranes. For membranes prepared from a casting solution consisting of PSF 26.0, NMP 28.0, THF 28.0, and EtOH 18.0 wt % and ET for 3 min, the maximum selectivity of untreated membrane is about 69.76 and 12.59 for CO2/CH4 and O2/N2, respectively. After plasma treatment, the ideal selectivity is receded; however, the CO2/CH4 is still higher than 40.41 at pressure of 5 bars. Finally, preparation conditions and DC glow discharge plasmas have significant effects on the characteristics of the PSF membranes and result in an increase of the gas permeation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42116.  相似文献   

16.
Miscible blend membranes containing 10 wt % PEG of low molecular weight 200, 600, 2000, and 6000, and 10 wt %, 20 wt %, 30 wt %, 40 wt %, 50 wt %, and 60 wt % of molecular weight 20,000 were prepared to investigate the effect of PEG on gas permeabilities and selectivities for CO2 over N2 and CH4. The permeabilities of CO2, H2, O2, CH4, and N2 were measured at temperatures from 30 to 80°C and pressures from 20 cmHg to 76 cmHg using a manometric permeation apparatus. It was determined that the blend membrane, which contained 10% PEG 20,000, exhibited higher permeability for CO2 and higher permselectivity for CO2 over N2 and CH4 than those of the membranes that contained 10% PEG of the molecular weight ranging from 200 to 6000. The high PEG 20,000 content blend membranes showed remarkable permeation properties such that the permeability coefficients of CO2 and the ideal separation factors for CO2 over N2 reached above 200 barrer and 22, respectively, at 70°C and 20 cmHg. Based on the data of gas permeability coefficients, time lags, and characterization of the membranes, it is proposed that the apparent solubility coefficients of all CA and PEG blend membranes for CO2 were lower than those of the CA membrane. However, almost all of the blend membranes containing PEG 20,000 showed higher apparent diffusivity coefficients for CO2, resulting in higher permeability coefficients of CO2 than those of the CA membrane. It is attributed to the high diffusivity selectivities of CA and PEG 20,000 blend membranes that their ideal separation factors for CO2 over N2 were higher than those of the CA membrane in the temperature range from 50 to 80°C, even though the ideal separation factors of all CA and PEG blend membranes for CO2 over CH4 became lower than those of the CA membrane over nearly the full temperature range from 30 to 80°C. © 1995 John Wiley & Sons, Inc.  相似文献   

17.
Copolyimides were synthesized from 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 4‐aminophenyl ether (ODA) with 4‐aminophenyl sulfone (DDS), 4,4′‐methylenedianiline (MDA), 4,4′‐bis(3‐aminophenoxy)diphenyl sulfone (BADS), 4,4′‐bis(3‐aminophenoxy) benzophenone (BABP), and 2,6‐bis(3‐aminophenoxyl) benzonitrile (DABN) as the third monomer. Surface free energies and interfacial free energies were calculated for comparison of the membrane hydrophilicity. Gas permeation was carried out with N2, O2, H2, He, and CO2, and the moiety contributions to membrane selectivity were calculated. DDS and BADS moieties contribute negatively to the selectivities toward O2/N2, H2/N2, and He/N2, and the DABN moiety is favorable for improving CO2/N2 selectivity. Water permeation and dehydration of isopropanol were performed, and the linear moiety contribution method was applied to study the effects of the monomer structures on the temperature and feed concentration dependencies of the permeation flux. The steric effects of DDS and BADS moieties, as well as the interactions of BABP and DABN moieties with water, account for the differences in pervaporation properties of the membranes. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers  相似文献   

18.
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   

19.
The effects of NH3‐plasma and N2‐plasma treatments on rubbery polyethylene (PE) membranes on the permeation behavior for carbon dioxide (CO2), O2, and N2 were investigated with permeability measurements. The NH3‐plasma and N2‐plasma treatments on PE membranes increased both the permeation coefficient for CO2 and the ideal separation factor for CO2 with respect to N2. For O2 transport, both the permeation coefficient for O2 and the ideal separation factor for O2 with respect to N2 were increased. NH3‐plasma and N2‐plasma treatments on polymer membranes possibly bring about an augmentation of permeability and permselectivity simultaneously. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 383–387, 2006  相似文献   

20.
Studies were conducted on transport properties and separation performance of date pit/polysulfone composite membranes for CO2, CH4, N2, He, and H2 gases. Date seeds were obtained and processed into powder. Asymmetric flat sheet membrane was prepared by solvent casting method with 2–10 wt % date pit powder. Membrane characterization was done using high pressure gas permeation, X‐ray diffraction, thermogravimetric, and scanning electron microscope analyses. The separation performance and the plasticization resistance property were evaluated in terms of gas permeability, selectivity, and plasticization pressure, respectively. Time dependent performance properties were evaluated up to a pressure of 40 bar for 75 days. Results obtained showed the highest selectivity values of 1.54 (He/H2), 3.637 (He/N2), 2.538 (He/CO2), 2.779 (He/CH4), 3.179 (H2/N2), 3.907 (H2/CO2), 1.519 (CH4/N2), 1.650 (CO2/N2), and 1.261 (CO2/CH4) at 10 bar and 35 °C feed pressure and temperature, respectively. The resulting composite membrane showed about 39.50 and 66.94% increase in the selectivity of He/N2 and CO2/CH4, respectively, as compared to the pure polysulfone membrane. Thus, the membrane composites possess some potentials in membrane gas separation. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43606.  相似文献   

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