Novel Zeolite-polyurethane membrane for environmental applications and gas separations (original) (raw)
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Separation of C3H8 and C2H6 from CH4 in polyurethane–zeolite 4Å and ZSM-5 mixed matrix membranes
Separation and Purification Technology, 2015
In this research, the effects of Zeolite 4Å and ZSM-5 on the separation of C 2 H 6 and C 3 H 8 from CH 4 through polyurethane/zeolite mixed matrix membranes (MMM) are evaluated. Physical properties of synthesized polyurethane and polyurethane/zeolite MMM were investigated by FTIR, XRD, TGA and SEM analyses. Results indicate that phase separation of hard and soft segments in polyurethane would be increased by adding butanediamine (BDA) chain extender in polymer due to the generation of more hydrogen bonds between hard segment domains. The obtained SEM micrographs confirm that the Zeolite is distributed in the polymer matrix homogenously. The results of gas permeation represent that permeability and selectivity of Hydrocarbons are increased by increasing the urea groups in the polymer structure. Moreover, the obtained results of gas permeation of polyurethane-zeolite (4Å) membranes indicate an increase in the permeability of Methane, with the reduction in C 2 H 6 /CH 4 and C 3 H 8 /CH 4 selectivity by increasing the Zeolite 4Å up to 10 wt%. In addition, the results of the gas permeation of polyurethanezeolite (ZSM-5) MMM indicate a significant increment in permeability and selectivity of all Hydrocarbons. The permeability of Propane and its selectivity over Methane is increased from 64.8 Barrer and 2.6 into 117.2 Barrer and 3.64 in with 20 wt% filled PU-ZSM 5 MMM, respectively.
Modified Zeolite/Polysulfone Mixed Matrix Membrane for Enhanced CO2/CH4 Separation
Membranes, 2021
In recent years, mixed matrix membranes (MMMs) have received worldwide attention for their potential to offer superior gas permeation and separation performance involving CO2 and CH4. However, fabricating defect-free MMMs still remains as a challenge where the incorporation of fillers into MMMs has usually led to some issues including formation of undesirable interfacial voids, which may jeopardize the gas separation performance of the MMMs. This current work investigated the incorporation of zeolite RHO and silane-modified zeolite RHO (NH2–RHO) into polysulfone (PSf) based MMMs with the primary aim of enhancing the membrane’s gas permeation and separation performance. The synthesized zeolite RHO, NH2–RHO, and fabricated membranes were characterized by X-ray diffraction (XRD) analysis, Fourier transform infrared-attenuated total reflection (FTIR-ATR), thermogravimetric analysis (TGA) and field emission scanning election microscopy (FESEM). The effects of zeolite loading in the MMMs ...
Journal of Membrane Science, 2001
Faujasite type zeolite membranes were synthesized on porous ceramic alumina supports by using direct (in situ) and secondary (seeded) growth methods. In the secondary growth method a seed layer of ZSM-2 nanocrystals (prepared according to a report by Schoeman et al. J. Colloid Interface Sci. 1995, 170, 449-456) was deposited on the surface of the support before the hydrothermal growth. For both in situ and secondary growth, the mixture composition was 4.17 Na 2 O:1.0 Al 2 O 3 :10 TEA (triethanol ammonium):1.87 SiO 2 :460 H 2 O. X-ray diffraction (XRD), scanning electron microscopy (SEM), and electron microprobe analysis (EPMA), indicate well intergrown 5-30 m thick FAU films with Si/Al ∼1-1.5. The separation of saturated/unsaturated hydrocarbon mixtures is demonstrated over a range of temperatures (40-160 • C). The mixtures examined (and the corresponding equimolar mixture separation factors) are benzene/cyclohexane (160), benzene/n-hexane (144), toluene/n-heptane (45), propylene/propane (6.2), and ethylene/methane (8.4). In all cases, the membranes are unsaturated hydrocarbon permselective. With equimolar feed mixtures (5 kPa/5 kPa benzene/cyclohexane) and in the temperature range 65-160 • C, the membranes exhibit separation factor of 20-160 with the benzene flux in the range 10 −4 -10 −3 mol m −2 s −1 . Decreasing the total feed partial pressure (0.31/0.31 kPa benzene/cyclohexane) reduces both separation factor (12) and benzene flux. Similar trend is observed when the benzene/cyclohexane ratio in the feed mixture (0.5/9.5 kPa benzene/cyclohexane) is reduced. A sorption diffusion model based on the Stefan-Maxwell formulation has also been employed to show that the benzene/cyclohexane separation can mainly be attributed to differences of their adsorption properties.
Journal of Industrial and Engineering Chemistry
Polymeric membrane technology has received extensive attention in the field of gas separation, recently. However, the tradeoff between permeability and selectivity is one of the biggest problems faced by pure polymer membranes, which greatly limits their further application in the chemical and petrochemical industries. To enhance gas separation performances, recent works have focused on improving polymeric membranes selectivity and permeability by fabricating mixed matrix membranes (MMMs). Inorganic zeolite materials distributed in the organic polymer matrix enhance the separation performance of the membranes well beyond the intrinsic properties of the polymer matrix. This concept combines the advantages of both components: high selectivity of zeolite molecular sieve, and mechanical integrity as well as economical processability of the polymeric materials. In this paper gas permeation mechanism through polymeric and zeolitic membranes, material selection for MMMs and their interacti...
Amine-functionalized zeolite FAU/EMT-polyimide mixed matrix membranes for CO2/CH4 separation
Journal of Membrane Science, 2011
This study describes the preparation, characterization and application of mixed matrix membranes (MMMs) made from as-synthesized FAU/EMT intergrowth zeolites grafted with 3aminopropylmethyldiethoxysilane (APMDES) as the inorganic phase and as-synthesized 6FDA-ODA polyimide as the organic phase. The amine grafting reaction was carried out under four different conditions in order to obtain zeolites having various amounts of amine groups grafted on their external surface. The percentage of aminegrafted on zeolites as well as the adsorption capacity for CO 2 of the samples have been measured for comparison. XRD, BET, and TG were performed to characterize the grafted zeolites. Finally, the grafted zeolites were incorporated in a 6FDA-ODA polyimide matrix, MMMs were casted and CO 2 /CH 4 gas separation tests were performed. MMMs were also characterized using ATR-FTIR, and SEM. The obtained results showed that at 25 wt.% zeolite in MMM and optimum grafting conditions, both the permeability and selectivity are increased compared to neat polyimide membrane.
The Volatile organic Compounds (VOCs) emitted in onshore and offshore facilities have been a major source of concern in the oil and gas industry. The compounds emitted are harmful to the environment and they constitute significant economic value that should not be wasted. The presence of inert gases which serve as blanket during the loading and offloading operations has led to some issues with the present technology. These gases are studied and the use of membrane technology for the recovery of these gases is explored. This work looks critically at the use of modified Y-type Zeolite membrane for the separation of CO2, He, C3H8, CH4, N2 and O2, with the aim of achieving high selectivity for the hydrocarbons and subsequent recovery of hydrocarbon gases under varying conditions; at temperatures of 298K, 373K, 473K and 573K and pressure ranges between about 0 - 2 x105 Pa. The Porous α-Al2O3 support was synthesised by a dip-coating process for zeolite membrane. Permeation test was carried out with the zeolite membrane and the flux of all the gases increased linearly as the gauge pressure increases. The positive activation energy values obtained for the hydrocarbons and carbon dioxide validated the high quality characteristics of zeolite membrane. The main transport mechanism governing the flow of the gases was molecular sieving. The high selectivity value of methane over gases at high temperatures validated the high thermal stability property of Y-type zeolite membrane structure at high temperature. The morphology of the modified zeolite membrane was observed with Scanning electron microscope. The elemental composition of the modified zeolite membrane was obtained using Energy Dispersive X-ray analysis. Silicon was found to be present in the result of the modified membrane; this indicated the presence of zeolite after modification. The surface area, pore volume and pore diameter of the membrane computed from the gas pressures using the Barrett, Joyner and Halenda (BJH) model from the Nitrogen physisorption measurement were given as 11.018m2/g, 0.168cc/g and 3.035nm respectively. The modified zeolite membrane was detected to be a micro-porous one.
In the recent years, zeolite T has been demonstrated as a potential materials for adsorption, catalysis, pervaporation as well as gaseous separation processes. However, the reported literature on the application of zeolite T as inorganic filler for the fabrication of mixed matrix membranes (MMMs) in CO 2 /CH 4 separation is not available. Therefore, in the present work, different loadings of zeolite T particles are embedded in 6FDA-durene polyimide. The morphology and structural properties of the resultant membranes were investigated using different analytical tools and the performance of the membranes in CO 2 and CH 4 gases separation were tested. The results showed that CO 2 permeability of 843.6 Barrer and CO 2 /CH 4 ideal selectivity of 19.1 were obtained using 1 wt% loaded zeolite T/6FDA-durene MMM, which were 80% and 172% higher than the CO 2 permeability and CO 2 /CH 4 ideal selectivity attained using pristine 6FDA-durene. Besides, the membrane showed improvement in CO 2 plasticization resistant up to 20 bar as compared to pristine 6FDA-durene membrane, which showed only 5 bar. Overall, zeolite T/6FDA-durene mixed matrix membranes fabricated in this work exhibited significant enhancement in CO 2 /CH 4 separation, which makes them an attractive candidate for industrial gas separation especially for natural gas purification.
INTERNATIONAL JOURNAL OF AUTOMOTIVE AND MECHANICAL ENGINEERING, 2018
Mixed matrix membranes (MMMs) comprising of unfunctionalized and aminefunctionalized T-type zeolite and 6FDA-based polyimide matrix were formulated. The physicochemical properties of the membranes were examined by FESEM, EDX, TGA and DSC. FESEM images showed that the enhancement of polymer-zeolite adhesion in MMM embedded with amine-functionalized T-type zeolite is trivial in comparison with MMM loaded with unfunctionalized T-type zeolite. From permeation test, permeability of CO2 of 858 Barrer and selectivity of CO2/CH4 of 22.5 was obtained using MMM incorporated with amine-functionalized T-type zeolite, whereas MMM incorporated with unfunctionalized T-type zeolite displayed permeability of CO2 of 844 Barrer and selectivity of CO2/CH4 of 19.1. Thus, selection of another suitable aminefunctionalization group might be required in later works to further improve MMM performance in capturing CO2 from CH4.
Ceramic-zeolite composite membranes and their application for separation of vapor/gas mixtures
Journal of Membrane Science, 1994
Ceramic-zeolite composite membranes were prepared by in-situ synthesis of a thin ( _ 10 pm) polycrystalline silicalite-1 layer on the inner surface of an alumina membrane tube. The inner surface is a y-alumina coating that has 5-nm diameter pores. X-ray diffraction verified the presence of a pure silicalite phase in the layer, and SEM showed that individual silicalite crystals had grown together to form a continuous silicalite-1 layer. The addition of silicalite to the alumina membrane decreased the Nz permeance by a factor of 5, but it decreased the n-C4Hu, permeance by a factor of 190, and n-C.,H10 appeared to adsorb on the membrane. At room temperature, the permeante ratio of n-C4H,,-,/i-C4Hlo was one for the alumina membrane, but it was 3 for the zeolite membrane. Methanol was separated from HZ and from CH4 at 373 K and pressures from 110 to 1100 kPa by preferentially permeating CH30H through the zeolite membrane. For some conditions the CH30H/H2 separation factor was greater than 1000, and the CHsOH/CH4 separation factor was 190. Apparently, CH30H adsorbs and blocks the pores for H2 or CH4 permeation.
STUDY OF PERMEATION OF GASES THROUGH CERAMIC SUPPORTED POLYMERIC AND ZEOLITE MEMBRANES
2 from various effluent gas mixtures. Membrane operations are recognized as feasible and economical operations over conventional technologies for gas separation due to a higher flexibility to tolerate fluctuations in feed composition and flow rate. In this present work Hydroxy Ethyl Cellulose (HEC) membrane prepared on Silicon carbide (SiC) tube and ZSM-5 membrane casted on α-Al 2 O 3 tube support is used to study the permeation characteristics of various gases. Pour and decanting technique is used to coat HEC membrane on SiC tube whereas seed growth hydrothermal technique is used to prepare ZSM-5 zeolite membrane. Scanning electron microscope (SEM) and X-ray diffraction techniques (XRD) are used to characterize the membranes. Single component permeation experiments are conducted for measurement of permeability coefficients which are essential for understanding and designing the membrane modules. Both the membranes have shown good permeation characteristics for all the gases. Ideal selectivity values are calculated from the pure component permeances.