The Experts below are selected from a list of 4812 Experts worldwide ranked by ideXlab platform
Ahmad Fauzi Ismail - One of the best experts on this subject based on the ideXlab platform.
-
polyaniline in situ modified halloysite nanotubes incorporated asymmetric Mixed Matrix Membrane for gas separation
Separation and Purification Technology, 2014Co-Authors: Surya R Murali, Takeshi Matsuura, Mahesh Padaki, Mohd Sohaimi Abdullah, Ahmad Fauzi IsmailAbstract:Abstract The embodiment of polyaniline in situ modified halloysite nanotubes (PANi–HNTs) on the gas permeation properties of CO2, CH4, O2, and N2 gases in polysulfone (PSf) Membrane has been investigated. Halloysite nanotubes (HNTs) were modified by in situ polymerization of aniline. Asymmetric Mixed Matrix Membranes (MMMs) were synthesized by varying the PANi–HNTs concentrations of 0.5–2.5 wt.% of polymer in the PSf solutions. The MMMs were characterized by SEM, ATR-IR, DSC and XRD. Membrane characterization reveals the structural change of the filler and interaction of PANi with PSf polymer Matrix. The permeance of pure gases and the ideal selectivities were determined using an indigenously built high-pressure gas separation manifold. Increasing the PANi–HNTs incorporation in polymer enhanced the permeance of CO2 from 17.4 to 68.4 GPU, CH4 from 0.8 to 4.8 GPU, O2 from 3.9 to 18.8 GPU and N2 from 0.7 to 3.1 GPU, respectively. The use of PANi–HNTs loaded PSf Membranes provides a means for separation of CO2/CH4, CO2/N2 and O2/N2.
-
asymmetric Mixed Matrix Membrane incorporating organically modified clay particle for gas separation
Chemical Engineering Journal, 2014Co-Authors: A K Zulhairun, Takeshi Matsuura, Mohd Sohaimi Abdullah, Ahmad Fauzi Ismail, Azeman MustafaAbstract:Abstract Asymmetric MMMs were fabricated containing various amount of organically modified clay particle (Cloisite® 15A) with the main intention to investigate the gas permeation behavior of the resultant material combination. The fabricated MMMs were characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM) and pure gas permeation testing. XRD analysis suggested that clay layers crystalline structure was slightly changed upon blending but only limited polymer chain intercalation occurred thus resulted in phase separated clay–polymer composite. The gas permeation properties were evaluated by pure gases: nitrogen, oxygen, methane, and carbon dioxide. The gas permeation rate was observed to be increasing with increasing clay content while the selectivity remained at par to that of unfilled PSF before it declined at 2 wt.% C15A loading due to filler agglomeration as confirmed by FESEM. The best results were obtained at 1 wt.% C15A loading where more than 270% enhancement in O2 and CO2 permeance were observed, with insignificant change in O2/N2 and CO2/CH4 selectivity compared to that of neat PSF.
-
fabrication and characterization of novel pes fe mn binary oxide uf Mixed Matrix Membrane for adsorptive removal of as iii from contaminated water solution
Separation and Purification Technology, 2013Co-Authors: Jamshidi R Gohari, Takeshi Matsuura, Woei Jye Lau, Ahmad Fauzi IsmailAbstract:Abstract In this work, novel ultrafiltration (UF) Mixed Matrix Membranes (MMMs) composed of organic polyethersulfone (PES) and inorganic Fe–Mn binary oxide (FMBO) particles were prepared through a phase inversion process for adsorptive elimination of As(III) from the contaminated water. The Membranes were prepared by casting solutions that consisted of different weight ratios of FMBO to PES, in the range of 0–1.5. The Membranes were then characterized with respect to crystallinity, surface roughness and morphology, using XRD, AFM and SEM, respectively. The pure water flux, hydrophilicity, porosity and As(III) adsorption capacity of the Membranes were also investigated. The increase in FMBO/PES ratio resulted in an increase in Membrane water flux which was attributable to the decreased contact angle, increased number of pores and greater surface roughness. Although skin layer thickness increased while pore size decreased with an increase of FMBO particles loading, the number of pores increased, which overrode the effects of the pore size and the skin layer thickness, contributing to increased water flux. The best performing Membranes prepared from the FMBO/PES ratio of 1.5:1 demonstrated the pure water flux as high as 94.6 L/m2 h at operating pressure of 1 bar and maximum As(III) uptake capacity of around 73.5 mg/g. The continuous UF experiment showed that the PES/FMBO Mixed Matrix Membrane can be potentially utilized for effective removal of As(III) from contaminated groundwater by producing permeate containing
-
enhanced hydrophilicity and salt rejection study of graphene oxide polysulfone Mixed Matrix Membrane
Desalination, 2013Co-Authors: B M Ganesh, Arun M Isloor, Ahmad Fauzi IsmailAbstract:Abstract Graphene oxide (GO) dispersed polysulfone (PSf) Mixed Matrix Membranes were prepared by wet phase inversion method. The morphology of Membranes was studied using scanning electron microscope (SEM) images. The variation in hydrophilicity was studied by measuring surface wettability and water swelling experiments. The performance of Membranes in terms of pure water flux and salt rejection was studied. SEM images depict enhanced macrovoids, while the contact angle data reveals that, GO incorporated Membrane surface is moderately hydrophilic. Membranes exhibited improved salt rejection after GO doping. Membrane with 2000 ppm GO loading has exhibited maximum of 72% Na2SO4 rejection at 4 bar applied pressure. The salt rejection seems to depend on pH of the feed solution and it has been witnessed that the salt rejection showed an increasing trend with increase in the pH.
-
enhanced hydrophilicity and salt rejection study of graphene oxide polysulfone Mixed Matrix Membrane
Desalination, 2013Co-Authors: B M Ganesh, Arun M Isloor, Ahmad Fauzi IsmailAbstract:Abstract Graphene oxide (GO) dispersed polysulfone (PSf) Mixed Matrix Membranes were prepared by wet phase inversion method. The morphology of Membranes was studied using scanning electron microscope (SEM) images. The variation in hydrophilicity was studied by measuring surface wettability and water swelling experiments. The performance of Membranes in terms of pure water flux and salt rejection was studied. SEM images depict enhanced macrovoids, while the contact angle data reveals that, GO incorporated Membrane surface is moderately hydrophilic. Membranes exhibited improved salt rejection after GO doping. Membrane with 2000 ppm GO loading has exhibited maximum of 72% Na2SO4 rejection at 4 bar applied pressure. The salt rejection seems to depend on pH of the feed solution and it has been witnessed that the salt rejection showed an increasing trend with increase in the pH.
A L Ahmad - One of the best experts on this subject based on the ideXlab platform.
-
interfacial sealing and functionalization of polysulfone sapo 34 Mixed Matrix Membrane using acetate based ionic liquid in post impregnation for co2 capture
Separation and Purification Technology, 2017Co-Authors: N N R Ahmad, Abdul Wahab Mohammad, C P Leo, A L AhmadAbstract:Abstract The CO2 selective ionic liquids (ILs) have been extensively studied in recent years, but their applications are limited by the high viscosity and cost. In this work, acetate-based ionic liquid was used to enhance and functionalize the interface between polysulfone (PSf) and SAPO-34 zeolite in the asymmetric Mixed Matrix Membrane (MMM) prepared via phase inversion. The MMMs were post-modified by immersing the Membranes into carboxylate IL solution (1-butyl-3-methylimidazolium acetate). The effects of IL concentration on the Membrane morphology and separation performance in CO2 separation were studied. Fourier transform infrared spectra and energy-dispersive X-ray spectra showed that the IL was successfully incorporated into MMM. The post-impregnation of the Membrane with IL improved the interface contact between the polymer and zeolite. The interfacial sealing using IL further enhanced the CO2/N2 selectivity of IL-modified MMM, about 818% higher than the CO2/N2 selectivity of unmodified MMM. The maximum selectivity of 39.60 was achieved using PSf Membrane incorporated with 5 wt% of SAPO zeolite loading and modified with 0.4 M of IL. This Membrane also sustained its separation performance even wet gas was fed.
-
modification of gas selective sapo zeolites using imidazolium ionic liquid to develop polysulfone Mixed Matrix Membrane for co2 gas separation
Microporous and Mesoporous Materials, 2017Co-Authors: N N R Ahmad, Abdul Wahab Mohammad, C P Leo, A L AhmadAbstract:Abstract Ionic liquids (ILs) with high CO 2 solubility and selectivity have been extensively studied in recent years to improve the performance of CO 2 separation Membranes. The progress in the development of supported IL Membranes, polymerized IL Membrane, polymer/IL gel Membranes and Membrane gas absorption using IL is limited by the high viscosity and price of ILs. In this work, the gas selective SAPO-34 zeolite was modified using [emim][TF 2 N] IL before the zeolites were incorporated into polysulfone (PSf) asymmetric Membrane which was prepared by phase inversion. The main objective of this work is to study the effects of immersion duration on the IL-functionality of zeolite, Membrane morphology and gas separation properties of PSf/SAPO-34 zeolite Mixed Matrix Membrane. The incorporation of IL into the SAPO zeolite was confirmed by energy dispersive X-ray analysis. This analysis also proved the well dispersion of SAPO-34 particles with IL modification for 6 h due to the improved polymer/filler interface morphology as shown by scanning electron microscopy analysis. The gas separation test further revealed that the Membrane containing SAPO-34 modified with IL for 6 h showed a great enhancement in both CO 2 /CH 4 and CO 2 /N 2 selectivity (approximately 486% and 232% respectively) over the unmodified Mixed Matrix Membrane.
-
a cellulose acetate multi walled carbon nanotube Mixed Matrix Membrane for co2 n2 separation
Journal of Membrane Science, 2014Co-Authors: A L Ahmad, Zeinab Abbas Jawad, Sharif Hussein Sharif ZeinAbstract:Abstract Carbon dioxide (CO 2 ) emissions have been rising indiscriminately and are becoming a major contributor to Earth's greenhouse effect. One of the most promising means of separating the hazardous CO 2 gas is to develop a cost effective and high-performance CO 2 separation Membrane. From the wide range of Membrane materials available, Mixed Matrix Membrane (MMM) technology has shown the most promising results. In this study, MMMs were synthesized from cellulose acetate (CA) with multi-walled carbon nanotubes (MWCNTs) using the wet phase inversion technique. The results shown that MMMs with functionalized MWCNTs (MWCNTs-F) demonstrated the enhance permeance and selectivity towards the separation of CO 2 /nitrogen (N 2 ). Thus, different loadings of MWCNTs-F into MMM were further investigated to interpret the physical morphologies and functionalities of MMMs, which enable the separation of CO 2 /N 2 in a specific manner. Gas permeation measurements showed excellent MMM performances in terms of permeance and selectivity at 0.1 wt% loadings of MWCNTs-F. This superior performance was due to the homogeneous dispersion between the MWCNTs-F and the CA Matrix, which increased the sufficient free volumes between the polymer chains and enlarged the polymer/nanofiller interface, as confirmed by the X-ray diffraction results.
-
preparation of pvdf tio2 Mixed Matrix Membrane and its evaluation on dye adsorption and uv cleaning properties
Chemical Engineering Journal, 2012Co-Authors: H P Ngang, Boon S Ooi, A L Ahmad, S O LaiAbstract:Abstract In this study, the polyvinylidene fluoride (PVDF)–Titanium dioxide (TiO 2 ) Mixed-Matrix Membranes were prepared via phase inversion technique. The properties of PVDF–TiO 2 Mixed-Matrix Membranes were characterized based on pore size distribution, Membrane porosity, field emission scanning electron microscope (FESEM) and photocatalytic behavior. The hydrophilicity of the Mixed-Matrix Membrane was enhanced and resulted in the improved pure water permeability (392.81 ± 10.93 l/m 2 h bar) compared to that 76.99 ± 4.87 l/m 2 h bar of the neat Membrane. The neat and Mixed-Matrix Membranes were further investigated in terms of filtration, adsorption and UV-cleaning properties based on methylene blue (MB) solution. Mixed-Matrix Membranes showed excellent removal efficiency (∼99%) when sodium dodecyl sulfate (SDS) was introduced into the MB feed solution. The produced Mixed-Matrix Membrane shows some slight photocatalytic properties improvement as FTIR results reviewed that the cleavage of C N bonding due to MB adsorption reduced more significantly with the presence of TiO 2 NPs and ultraviolet (UV) light irradiation. The UV-cleaning properties of the Mixed-Matrix Membrane were further proved by the 100% flux recovery ratios (FRRs) for Mixed-Matrix Membrane, suggesting that the embedded TiO 2 NPs was photocatalytically active and able to degrade the adsorbed MB in the Membrane.
-
preparation and characterization of pvdf tio2 Mixed Matrix Membrane via in situ colloidal precipitation method
Desalination, 2012Co-Authors: Yeit Haan Teow, A L Ahmad, Jitkang Lim, Boon S OoiAbstract:Abstract In this study, titanium dioxide (TiO2) nanoparticles (NPs) were incorporated into polyvinylidene fluoride (PVDF) Membrane to produce a Mixed Matrix Membrane via phase inversion and colloidal precipitation method. In order to avoid agglomeration and to maintain the stability of NPs in the coagulation bath, NPs were dispersed in the bath via sonication and peptization. The Membrane surface morphology and distribution pattern of NPs on the Membrane surface were observed by field emission scanning electron microscopy. It was found that the NP size and distribution of NPs on the Membrane surface were affected to a very great extent by the type of solvent used in the dope formulation and concentration of TiO2 in the coagulation bath. Membrane prepared using N-methyl-2-pyrrolidone (NMP) as solvent has smaller surface particles and narrower particle size distribution compared to N-N-dimethylacetamide (DMAc) and N,N-dimethyl formamide (DMF) due to the hydrophobic/hydrophilic interactions between NPs and polymer solution. However, the pore size of Membrane prepared using NMP was relatively big, thus resulted in poorer humic acid (HA) rejection. PVDF/TiO2 Mixed Matrix Membrane using DMAc as solvent with 0.01 g/L of TiO2 in the coagulation bath exhibited extraordinary permeability (43.21 L/m2 h) with superior retention properties (98.28%) of humic acid.
William J. Koros - One of the best experts on this subject based on the ideXlab platform.
-
enhanced co2 ch4 separation performance of a Mixed Matrix Membrane based on tailored mof polymer formulations
Advanced Science, 2018Co-Authors: Yang Liu, Chen Zhang, Gongping Liu, Wulin Qiu, Valeriya Chernikova, Zhijie Chen, Youssef Belmabkhout, Osama Shekhah, Mohamed Eddaoudi, William J. KorosAbstract:Membrane-based separations offer great potential for more sustainable and economical natural gas upgrading. Systematic studies of CO2/CH4 separation over a wide range of temperatures from 65 °C (338 K) to as low as -40 °C (233 K) reveals a favorable separation mechanism toward CO2 by incorporating Y-fum-fcu-MOF as a filler in a 6FDA-DAM polyimide Membrane. Notably, the decrease of the temperature from 308 K down to 233 K affords an extremely high CO2/CH4 selectivity (≈130) for the hybrid Y-fum-fcu-MOF/6FDA-DAM Membrane, about four-fold enhancement, with an associated CO2 permeability above 1000 barrers. At subambient temperatures, the pronounced CO2/CH4 diffusion selectivity dominates the high permeation selectivity, and the enhanced CO2 solubility promotes high CO2 permeability. The differences in adsorption enthalpy and activation enthalpy for diffusion between CO2 and CH4 produce the observed favorable CO2 permeation versus CH4. Insights into opportunities for using Mixed-Matrix Membrane-based natural gas separations at extreme conditions are provided.
-
high performance zif 8 6fda dam Mixed Matrix Membrane for propylene propane separations
Journal of Membrane Science, 2012Co-Authors: Chen Zhang, Ying Dai, J R Johnson, Oguz Karvan, William J. KorosAbstract:Abstract We report significantly enhanced propylene/propane (C 3 H 6 /C 3 H 8 ) selectivity in Mixed Matrix Membranes fabricated using 6FDA-DAM polyimide and a zeolitic imidazolate framework (ZIF-8). Equilibrium isotherms and sorption kinetics of C 3 H 6 and C 3 H 8 at 35 °C were studied on a 200 nm commercially available ZIF-8 sample produced by BASF. Mixed Matrix dense films were formed with 6FDA-DAM and 200 nm BASF ZIF-8 particles. SEM imaging showed generally good adhesion between the ZIF-8 and 6FDA-DAM without the need for surface-treating ZIF-8. Pure gas permeation showed significantly enhanced Mixed Matrix ZIF-8/6FDA-DAM Membrane C 3 H 6 /C 3 H 8 separation performance over the pure 6FDA-DAM Membrane performance. A C 3 H 6 permeability of 56.2 Barrer and C 3 H 6 /C 3 H 8 ideal selectivity of 31.0 was found in ZIF-8/6FDA-DAM Mixed Matrix Membrane with 48.0 wt% ZIF-8 loading, which are 258% and 150% higher than the pure 6FDA-DAM Membrane, respectively for permeability and selectivity. Permeation properties of C 3 H 6 and C 3 H 8 in ZIF-8 were back-calculated by the Maxwell model for composite permeability using pure gas permeation data, leading to a C 3 H 6 permeability of 277 Barrer and C 3 H 6 /C 3 H 8 selectivity of 122. Mixed gas permeation also verified that selectivity enhancements were achievable in Mixed gas environment by ZIF-8.
-
Mixed Matrix Membranes using carbon molecular sieves: I. Preparation and experimental results
Journal of Membrane Science, 2003Co-Authors: William J. Koros, Stephen J. MillerAbstract:Abstract Carbon molecular sieves (CMSs) have been incorporated into two different polymer matrices to form Mixed Matrix Membrane films for gas separations. The CMSs were formed by pyrolysis of a polyimide (Matrimid ® ) precursor to a final temperature of 800 °C. The CMS Membrane films have an intrinsic CO 2 /CH 4 selectivity of 200 with a CO 2 permeability of 44 Barrers and an O 2 /N 2 selectivity of 13.3 with an O 2 permeability of 24 Barrers at 35 °C. The pyrolyzed CMS materials were ball-milled into fine particles, ranging in size from submicron to 2 μm, prior to dispersal in casting solvent. Mixed Matrix films comprising high CMS particle loadings (up to 35 wt.%) dispersed within two polymer matrices (Matrimid ® 5218 and Ultem ® 1000) were successfully formed from flat-sheet solution casting. For Ultem ® –CMS Mixed Matrix Membrane films, pure gas permeation tests show enhancements by as much as 40% in CO 2 /CH 4 selectivity over the intrinsic CO 2 /CH 4 selectivity of the pure Ultem ® polymer Matrix. Likewise, for Matrimid ® –CMS Mixed Matrix films, enhancements by as much as 45% in CO 2 /CH 4 selectivity were observed. Similar enhancements were observed when these Mixed Matrix Membrane films were examined for the O 2 /N 2 separation (8 and 20% for the Ultem ® –CMS and Matrimid ® –CMS Mixed Matrix films, respectively). Effective permeabilities of the fast-gas penetrants (O 2 and CO 2 ) through the Mixed Matrix Membranes were also significantly enhanced over the intrinsic permeabilities of the Ultem ® and Matrimid ® polymer matrices. These encouraging selectivity and permeability enhancements confirm that Mixed Matrix Membrane behavior is achievable with CMS particles.
-
Mixed Matrix Membrane materials with glassy polymers part 2
Polymer Engineering and Science, 2002Co-Authors: Rajiv Mahajan, William J. KorosAbstract:Analysis presented in Part 1 of this paper indicated the importance of optimization of the transport properties of the interfacial region to achieve ideal Mixed Matrix materials. This insight is used in this paper to guide Mixed Matrix material formation with more conventional gas separation polymers. Conventional gas separation materials are rigid, and, as seen earlier, lead to the formation of an undesirable interphase under conventional casting techniques. We show in this study that if flexibility can be maintained during Membrane formation with a polymer that interacts favorably with the sieve, successful Mixed Matrix materials result, even with rigid polymeric materials. Flexibility during Membrane formation can be achieved by formation of films at temperatures close to the glass transition temperature of the polymer. Moreover, combination of chemical coupling and flexibility during Membrane formation produces even more significant improvements in Membrane performance. This approach leads to the formation of Mixed Matrix material with transport properties exceeding the upper bound currently achieved by conventional Membrane materials. Another approach to form successful Mixed Matrix materials involves tailoring the interface by use of integral chemical linkages that are intrinsically part of the chain backbone. Such linkages appear to tighten the interface sufficiently to prevent “nonselective leakage” along the interface. This approach is demonstrated by directly bonding a reactive polymer onto the sieve surface under proper processing conditions.
-
Mixed Matrix Membrane materials with glassy polymers part 1
Polymer Engineering and Science, 2002Co-Authors: Rajiv Mahajan, William J. KorosAbstract:Mixed Matrix materials comprising molecular sieve entities embedded in a polymer Matrix can economically increase Membrane permselectivity, thereby addressing a key challenge hindering the widespread use of Membrane-based gas separations. Prior work has clarified the importance of proper selection of the dispersed sieve phase and the continuous Matrix phase based on their intrinsic transport properties. Proper material selection for the two components, while necessary, is not sufficient since the interfacial contact zone appears to be equally important to achieve optimum transport properties. Specifically, it was found that chemical coupling of the sieve to the polymer can lead to better macroscopic adhesion but to even poorer transport properties than in the absence of the adhesion promoter. This counterintuitive behavior may be attributed to a nanometric region of disturbed packing at the polymer sieve interphase. The poor properties are believed to result from “leakage” of gas molecules along this nanometric interface. The Maxwell model was modified to take into account these complexities and to provide a first order quantification of the nanometric interphase. The analysis indicates that optimization of the transport properties of the interfacial region is key to the formation of ideal Mixed Matrix materials. This approach is used in the second part of this paper to form successful Mixed Matrix Membrane materials.
May-britt Hägg - One of the best experts on this subject based on the ideXlab platform.
-
development of dual layer of zif 8 pebax 2533 Mixed Matrix Membrane for co2 capture
Journal of Membrane Science, 2014Co-Authors: Vajiheh Nafisi, May-britt HäggAbstract:Abstract A new kind of self-supported dual layer Mixed Matrix Membrane was developed in this work using ZIF-8 as inorganic filler in PEBAX-2533 polymer Matrix. The developed dual layer flat sheet Mixed Matrix Membrane was characterized to investigate the morphology of organic-based and inorganic-based layer. The gas separation properties of the Mixed Matrix Membranes were tested using single gases CO2, CH4, N2, and O2 and a mixture of CO2 and N2 in dry and humidified conditions. The permeability of all examined gases increased as the inorganic filler content increased in the Matrix Membranes, and specifically it increased dramatically for CO2 in all cases, single feed gas and dry and humidified Mixed gas. The CO2/N2 selectivity decreased slightly from 33.8 for the pure PEBAX Membrane to 32.3 for the Mixed Matrix Membrane with 35% ZIF-8 loading, while more significant drop in CO2/N2 selectivity was observed in experiments using Mixed gases.
-
gas separation properties of zif 8 6fda durene diamine Mixed Matrix Membrane
Separation and Purification Technology, 2014Co-Authors: Vajiheh Nafisi, May-britt HäggAbstract:Abstract Mixed Matrix Membranes of ZIF-8 as inorganic filler in polymer Matrix of synthesized 6FDA-durene diamine was developed in this work. Pure gas permeation for the gases CO 2 , CH 4 , N 2 , and O 2 and Mixed gas of CO 2 /N 2 was carried out at 2 and 6 bar for single gas and 2.6 bar for Mixed gas using the Mixed Matrix Membrane of ZIF-8/6FDA-durene diamine in different inorganic filler loading. The homogenous dispersion of ZIF-8 particles in polymer confirmed by SEM result in dramatic increase in gas permeability for all tested gases and significant increase in CO 2 permeability from 1468 Barrer to 2185 Barrer corresponding to pure polymer Membrane and 30 wt% loaded ZIF-8 Mixed Matrix Membrane at 2 bar feed gas pressure, respectively. However a loss in both CO 2 /N 2 and CO 2 /CH 4 selectivity was observed. Incorporation of inorganic fillers in Membrane results in increment of decomposition temperature of Mixed Matrix Membranes while no significant change in T g was observed.
-
preparation and characterization of polyvinyl acetate zeolite 4a Mixed Matrix Membrane for gas separation
Journal of Membrane Science, 2013Co-Authors: Jamil Ahmad, May-britt HäggAbstract:Abstract The demand and consumption of fossil fuels have increased in the past and continue to increase in future. The combustion of these fossil fuels produce various harmful gases i.e CO 2 , SO 2 , H 2 S etc. that pose potential threat to the environment. Currently the development of new Membrane materials is the focus of research in Membrane based gas separation. Pure PVAc and PVAc/4A Mixed Matrix Membranes were prepared using dichloromethane as a solvent and the solution casing method. The resulting Membranes were characterized by optical microscope, FESEM, DSC, TGA, XRD and single gas permeation. Optical microscope was used to find out the initial thickness of Membranes that ranges from 70 μm to 90 μm. Zeolite 4A particles upto 35 wt% were homogenously dispersed within the polymer without aggregation as shown by the FESEM results. The addition of 4A particles have improved the thermal stability of PVAc in the resulting MMMs as depicted by an increase in the glass transition temperature ( T g ) and TGA results. In single gas permeation, the effects of zeolite 4A loading, operating temperature and pressure on the separation properties were investigated. The obtained results show that the addition of zeolite 4A up to 25 wt% has increased the selectivity of gas pairs O 2 /N 2 , H 2 /N 2 and CO 2 /N 2 by 25%, 37% and 70% respectively with a corresponding decrease in their permeability. Temperature increase from 30 °C to 50 °C has a positive effect on permeabilities with a maximum of (1.19)×3.348×10 −19 kmol m/(m 2 s Pa) (barrer) for O 2 , (17.55)×3.348×10 −19 kmol m/(m 2 s Pa) (barrer) for H 2 and (9.35)×3.348×10 −19 kmol m/(m 2 s Pa) (barrer) for CO 2 and a negative effect on their selectivity over N 2 . As the pressure is increased from (2)×100,000 Pa (bars) to 8×100,000 Pa (bars), permeability of H 2 almost remains constant and slightly increases for O 2 . Permeability of N 2 and CO 2 is decreased and increased respectively leading to increased selectivity of CO 2 /N 2 as well as H 2 /N 2 and O 2 /N 2 . The obtained results are consistent with the reported literature data.
Chen Zhang - One of the best experts on this subject based on the ideXlab platform.
-
enhanced co2 ch4 separation performance of a Mixed Matrix Membrane based on tailored mof polymer formulations
Advanced Science, 2018Co-Authors: Yang Liu, Chen Zhang, Gongping Liu, Wulin Qiu, Valeriya Chernikova, Zhijie Chen, Youssef Belmabkhout, Osama Shekhah, Mohamed Eddaoudi, William J. KorosAbstract:Membrane-based separations offer great potential for more sustainable and economical natural gas upgrading. Systematic studies of CO2/CH4 separation over a wide range of temperatures from 65 °C (338 K) to as low as -40 °C (233 K) reveals a favorable separation mechanism toward CO2 by incorporating Y-fum-fcu-MOF as a filler in a 6FDA-DAM polyimide Membrane. Notably, the decrease of the temperature from 308 K down to 233 K affords an extremely high CO2/CH4 selectivity (≈130) for the hybrid Y-fum-fcu-MOF/6FDA-DAM Membrane, about four-fold enhancement, with an associated CO2 permeability above 1000 barrers. At subambient temperatures, the pronounced CO2/CH4 diffusion selectivity dominates the high permeation selectivity, and the enhanced CO2 solubility promotes high CO2 permeability. The differences in adsorption enthalpy and activation enthalpy for diffusion between CO2 and CH4 produce the observed favorable CO2 permeation versus CH4. Insights into opportunities for using Mixed-Matrix Membrane-based natural gas separations at extreme conditions are provided.
-
relationship between Mixed and pure gas self diffusion for ethane and ethene in zif 8 6fda dam Mixed Matrix Membrane by pulsed field gradient nmr
Journal of Membrane Science, 2016Co-Authors: Robert Mueller, Ryan P Lively, Chen Zhang, Venkatachalam Hariharan, Sergey VasenkovAbstract:Abstract Pulsed field gradient (PFG) NMR was applied to study self-diffusion of an ethane/ethene mixture and the corresponding pure gases in a Mixed-Matrix Membrane (MMM) formed by dispersing ZIF-8 particles in 6FDA-DAM polymer. In addition to the MMM, diffusion measurements of the pure gases were also carried out for the Membrane constituents, i.e. ZIF-8 particle bed and the pure polymer film. PFG NMR studies were performed at a high magnetic field of 17.6 T using large magnetic field gradients up to 30 T/m. The former allowed achieving sufficiently large signal-to-noise ratios, while the latter enabled diffusivity measurements to be performed for molecular displacements smaller than the size of ZIF-8 particles. As a result, the gas self-diffusivities for the diffusion inside the ZIF-8 particles dispersed in the MMM and for the diffusion inside the surrounding polymer Matrix could be obtained separately. For each gas, the diffusivities inside the ZIF-8 and polymer phases of the MMM were found to be smaller than the corresponding diffusivities in the neat ZIF-8 particle bed and pure polymer film. This observation is explained by the reduced framework flexibility of ZIF-8 and the polymer chain rigidification in the MMM. The ethane and ethene diffusivities in the MMM loaded with the ethane/ethene mixture were compared with the corresponding diffusivities in the MMM loaded with a single gas. It was found that the presence of another gas component in the ZIF-8 particles dispersed in the MMM does not change the self-diffusivity inside the particles for both gases. At the same time, the self-diffusivity of the faster-diffusing sorbate (ethene) in the polymer phase of the MMM was reduced by co-adsorption of the slower-diffusing sorbate (ethane) in the MMM. The analytical expression proposed in our previous work for the long-range diffusivity in MMMs was validated for gas mixtures and pure gases based on the experimental data reported in this work.
-
relationship between long range diffusion and diffusion in the zif 8 and polymer phases of a Mixed Matrix Membrane by high field nmr diffusometry
Journal of Membrane Science, 2015Co-Authors: Robert Mueller, Suihua Zhang, Ryan P Lively, Chen Zhang, Sergey VasenkovAbstract:Abstract Pulsed field gradient (PFG) NMR is applied to resolve different modes of ethene self-diffusion inside a Mixed-Matrix Membrane (MMM) consisting of ZIF-8 particles embedded in 6FDA–DAM polymer: (i) diffusion inside the ZIF-8 particles, (ii) diffusion inside the surrounding polymer Matrix, and (iii) diffusion under conditions of an exchange between the particles and the polymer over length scales smaller than and comparable with the Membrane thickness. This resolution is achieved using C-13 PFG NMR studies at a high magnetic field of 17.6 T and large magnetic field gradients up to 30 T/m. C-13 PFG NMR was also applied to measure ethene diffusion in the constituent components used in the MMM formation: a bed of ZIF-8 particles and a pure 6FDA–DAM polymer. It is shown that the comparison of all the measured diffusion data elucidates details of sorbate diffusion and diffusion mediated exchange dynamics between the ZIF-8 particles and the polymer in the MMM. An exchange model is applied to connect the long-range diffusivity measured for displacements larger than the size of ZIF-8 particles in the MMM with the diffusivities measured inside the ZIF-8 particles and the polymer.
-
high performance zif 8 6fda dam Mixed Matrix Membrane for propylene propane separations
Journal of Membrane Science, 2012Co-Authors: Chen Zhang, Ying Dai, J R Johnson, Oguz Karvan, William J. KorosAbstract:Abstract We report significantly enhanced propylene/propane (C 3 H 6 /C 3 H 8 ) selectivity in Mixed Matrix Membranes fabricated using 6FDA-DAM polyimide and a zeolitic imidazolate framework (ZIF-8). Equilibrium isotherms and sorption kinetics of C 3 H 6 and C 3 H 8 at 35 °C were studied on a 200 nm commercially available ZIF-8 sample produced by BASF. Mixed Matrix dense films were formed with 6FDA-DAM and 200 nm BASF ZIF-8 particles. SEM imaging showed generally good adhesion between the ZIF-8 and 6FDA-DAM without the need for surface-treating ZIF-8. Pure gas permeation showed significantly enhanced Mixed Matrix ZIF-8/6FDA-DAM Membrane C 3 H 6 /C 3 H 8 separation performance over the pure 6FDA-DAM Membrane performance. A C 3 H 6 permeability of 56.2 Barrer and C 3 H 6 /C 3 H 8 ideal selectivity of 31.0 was found in ZIF-8/6FDA-DAM Mixed Matrix Membrane with 48.0 wt% ZIF-8 loading, which are 258% and 150% higher than the pure 6FDA-DAM Membrane, respectively for permeability and selectivity. Permeation properties of C 3 H 6 and C 3 H 8 in ZIF-8 were back-calculated by the Maxwell model for composite permeability using pure gas permeation data, leading to a C 3 H 6 permeability of 277 Barrer and C 3 H 6 /C 3 H 8 selectivity of 122. Mixed gas permeation also verified that selectivity enhancements were achievable in Mixed gas environment by ZIF-8.