Dissertations / Theses: 'Membrane-based separation'

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Henderson, J. S. "Combined microfiltration and membrane-based affinity separation." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325959.

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Banchik, Leonardo David. "Advances in membrane-based oil/water separation." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108950.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 117-124).
Oil is a widespread pollutant from oil spills to industrial oily wastewater in the oil and gas, metalworking, textile and paper, food processing, cosmetics, and pharmaceutical industries. A wastewater of particular concern is produced water, an oily waste stream from hydrocarbon extraction activities. Worldwide, over 2.4 billion US gallons of produced water is generated every day. Membrane technologies have emerged as the preferred method for treating these wastewaters; this has allowed operators to reclaim and reuse fresh water for potable, industrial, and agricultural use and to meet waste discharge regulations. Yet, despite their technological predominance, membranes can become severely fouled and irreversibly damaged when bulk and small stabilized oil droplets, emulsions, are present in intake streams. In this thesis, we seek to mitigate these deleterious effects through several means. First we seek to better understand fouling by oil-in-water emulsions on conventional polymeric ultrafiltration membranes. We investigate the decrease in water production over time using model and actual produced water samples with varying solution zeta potentials and make meaningful recommendations to operators based on our observations. Next, we develop a robust multifunctional membrane which can in one step degrade organic pollutants and separate bulk and surfactant-stabilized oil/water mixtures while achieving high fluxes, high oil rejection, and high degradation efficiencies. Finally, we investigate the potential of novel in-air hydrophilic/oleophobic microfiltration and reverse osmosis membranes for their anti-oil fouling performance relative to conventional hydrophilic/oleophilic membranes. Contrary to claims in literature of superior performance, we find that in-air oleophobicity does not aid in underwater anti-fouling due to surface reconstruction of mobile perfluoroalkyl chains in the presence of water. Based on these observations, we discuss opportunities for future research on oil anti-fouling membranes using fluorinated moieties.
by Leonardo David Banchik.
Ph. D.

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Zhou, Yi. "Membrane-Based Gas Separation For Carbon Capture." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1595254659184073.

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Lin, Han. "GRAPHENE OXIDE-BASED MEMBRANE FOR LIQUID AND GAS SEPARATION." University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1595260029225206.

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Bissett, Hertzog. "Membrane based separation of nitrogen, tetrafluoromethane and hexafluoropropylene / Bissett, H." Thesis, North-West University, 2012. http://hdl.handle.net/10394/6999.

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Pure fluorocarbon gases can be sold for up to 30 USD/kg, if they were manufactured locally. Due to the absence of local demand, South Africa at present has less than 0.3 % of the fluorochemical market and most fluoro–products used in the South African industry are currently imported. The depolymerisation of waste polytetrafluoroethylene (PTFE or Teflon) filters in a nitrogen plasma reactor results in the mixture of gases which includes N2, CF4 and C3F6. An existing challenge entails the separation of these gases, which is currently attained by an energy intensive cryogenic distillation process. Both the small energy requirements as well as the small process streams required, make a membrane separation an ideal alternative to the current distillation process. Based on our research groups existing expertise in the field of zeolite membranes, it was decided to investigate the separation capability of zeolite (MFI, NaA, NaY, and hydroxysodalite) coated tubular ceramic membranes for the separation of the above mentioned gases. The separation study was subdivided into adsorption studies as well as single and binary component studies. CxFy gas adsorption on MFI zeolites. Tetrafluoromethane (CF4) and hexafluoropropylene (C3F6) were adsorbed on zeolite ZSM–5 and silicalite–1 to help explain permeation results through zeolite membranes. According to the obtained data, the separation of CF4 and C3F6 would be possible using adsorption differences. The highest ideal selectivities (~ 15) were observed at higher temperatures (373 K). While the CF4 adsorption data did not fit any isotherm, the heat of adsorption for C3F6 adsorbed on ZSM–5 and silicalite–1 was calculated as –17 and –33 kJ/mol respectively. Single gas permeation. A composite ceramic membrane consisting of a ceramic support structure, a MFI intermediate zeolite layer and a Teflon AF 2400 top layer was developed for the separation of N2, CF4 and C3F6. The adsorption properties of the Teflon AF 2400 sealing layer was investigated. A theoretical selectivity, in terms of the molar amount of gas adsorbed, of 26 in favour of the C3F6 vs CF4 was calculated, while the N2 adsorption remained below the detection limit of the instrument. While the ideal N2/CF4 and N2/C3F6 selectivities for the MFI coated support were either near or below Knudsen, it was 5 and 8 respectively for the Teflon coated support. Ideal selectivities improved to 86 and 71 for N2/CF4 and N2/C3F6 when using the composite ceramic membrane, while CF4/C3F6 ideal selectivities ranged from 0.9 to 2, with C3F6 permeating faster though the composite ceramic membrane. Zeolite based membrane separation. Inorganic membranes (?–alumina support, NaA, NaY, hydroxysodalite, MFI) and composite membranes (Teflon layered ceramic and composite ceramic membrane) were synthesized and characterized using the non–condensable gases N2, CF4 and C3F6. For the inorganic membranes either near or below Knudsen selectivities were obtained during single gas studies, while higher selectivities were obtained for the composite membranes. Subsequently, the MFI, hydroxysodalite and both composite membranes were chosen for binary mixture separation studies. The membranes exhibited binary mixture permeances in the order Teflon layered ceramic > hydroxysodalite > MFI > composite ceramic, which was comparable to the single gas permeation results. The highest separation for N2/CF4 (4) and N2/C3F6 (2.4) was obtained with the composite ceramic membrane indicating that the Teflon layer was effective in sealing non–zeolitic pore in the intermediate zeolite layer. The aim of this project was met successfully by investigating a method of fluorocarbon gas separation by zeolite based membranes using various inorganic and composite membranes with single and binary mixtures.
Thesis (Ph.D. (Chemistry))--North-West University, Potchefstroom Campus, 2012.

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Williams, Rhodri John. "Methanoanthracene-based polymers of intrinsic microporosity for membrane applications." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28924.

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Polymers were synthesised containing the methanoanthracene (MA), methanopentacene (MP) and benzomethanoanthracene (BzMA) units to investigate their properties as gas separation membranes. For each monomer type, polymers were successfully synthesised using Tröger’s base (TB) chemistry and cast as free standing films from low-boiling point solvents. Gas permeability tests revealed high selectivities for most of the technologically significant gas pairs. Most interestingly, MA/dimethylethanoanthracene co-polymer, MP-TB and BzMT-TB polymers all show a high degree of selectivity in the separation of a number of technologically significant gas pairs when compared to other state-of-the-art polymers. In particular MP-TB has very high selectivity for the N2/O2 gas pair. Synthetic routes to MP-TB and BzMA-TB involve fewer steps and are significantly cheaper to implement compared to other state of the art TB polymers and high performance PIMs that provide data above the Robeson upper bounds due to their high permeability and selectivity. Co-polymers of MA were synthesised in 1:1, 4:1 and 9:1 ratios. Gas permeability data demonstrated that properties correlate with the monomer composition. Results indicate that inclusion of methano-bridged units into the polymers increased the rigidity of polymer chains, leading to smaller pore widths and improved selectivities compared to polymers such made from more flexible structural units. The first chapter of this thesis introduces the concepts of microporosity, permeability and membrane separation, and describes a number of polymers that have demonstrated properties of interest for separating gas mixtures. Chapter two describes the synthesis and gas permeability data of MA-TB polymer and a series of copolymers incorporating MA. Chapter 3 describes the synthesis of polymers containing the MP structural unit and describes the performance of MP-TB as a membrane for gas separation. Chapter 4 describes a number of polymers synthesised using the BzMA structural unit and chapter 5 reports the synthesis of a number of larger units derived from BzMA including benzomethanotetracene, benzomethanopentacene and dibenzomethanopentacene. Permeability data for TB polymers synthesised from BzMA-type monomers is reported in these chapters.

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Masciola, David A. "Development of a membrane resistance based modeling framework for comparison of ultrafiltration processes." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1651.

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Thesis (M.S.)--West Virginia University, 2000.
Title from document title page. Document formatted into pages; contains xxxvi, 252 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 249-252).

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Lin, Zhihao. "Second order fiber optic chemical sensors based upon membrane separation and spectroscopic detection /." Thesis, Connect to this title online; UW restricted, 1994. http://hdl.handle.net/1773/11588.

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Wang, Qiang. "Development and Characterization of Ethanol-Compatibilized PPO-Based EPMM Membranes." Thesis, Université d'Ottawa / University of Ottawa, 2011. http://hdl.handle.net/10393/20170.

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Emulsion polymerized mixed matrix (EPMM) membranes is a new category of membranes, which incorporate silica-based inorganic nanoparticles dispersed in continuous phase of an organic polymer. The uniqueness of the EPMM membranes comes from the fact that they may combine otherwise incompatible inorganic and organic phases. This is achieved by the synthesis of the inorganic nanoparticles from a silica precursor in a stable emulsion, in which an aqueous phase is dispersed in a continuous phase of the polymer solution. More specifically, the silica precursor soluble in the polymer solution polymerizes in contact with the aqueous phase, and consequently the latter acts as finely dispersed micro reactors. The objective of this work was to optimize the previously developed protocol for the synthesis of poly (2,6-dimethyl-1,4pheneylene oxide) (PPO) based EPMM membranes, and to characterize their physical and gas transport properties. In particular, the effects of inorganic loading and the membrane post-treatment protocol on the permeability and selectivity of the membranes were of interest. However, the results showed that the obtained permeation and separation were virtually not affected by the theoretical Si loading and the post-treatment protocol. Moreover, in comparison to the base PPO membranes, the observed O2 permeability and the O2/N2 permselectivity have generally decreased. The differential scanning calorimetry (DSC) analysis of the synthesized membranes showed an important scatter of the glass transition temperatures (Tg) of the EPMM membranes with the values generally lower than the Tg of the base PPO. Moreover, the inductively coupled plasma mass spectrometry (ICP-MS) showed the silica content in selected EPMM membranes to be far below the expected theoretical level. This, in combination with the 29Si nuclear magnetic resonance (29Si NMR) results, showed that most of the already low silica content comes from the unreacted silica source (tetraethylorthosilicate) and have led to the second phase of the project in which a modified synthesis protocol has been developed. The major differences of the modified protocol compared to the original one include the replacement of a surfactant, 1-octanol, by ethanol and using greater concentrations of the reactants. To study the effect of different parameters involved in the synthesis protocol, a Gravimetric Powder experiment, in which the inorganic polymerization is carried out in an emulsion with a pure solvent rather than a polymer solution, has been designed. The Gravimetric Powder experiments have confirmed polymerization of tetraethylorthosilicate (TEOS) in the emulsion system. Using the conditions, which resulted in the maximum production of the polymerized TEOS in the Gravimetric Powder experiments, one set of new EPMM membranes has been synthesized and characterized. The new EPMM membranes have the Tg of 228.2oC, which is distinctly greater compared to the base PPO, and contain one order of magnitude more of silica compared to the old EPMM membranes. More importantly, the 29Si NMR analysis has proven that the silica content in the new EPMM membranes originates from the reacted rather than unreacted TEOS. Interestingly, the observed conversion of TEOS in the new EPMM membranes, exceeding 20%, is greater than the largest conversion in the Gravimetric Powder experiments. The oxygen permeability in the new EPMM membrane of 33.8 Barrer is more than twice that of the base PPO membrane. Moreover, this increase in O2 permeability is associated with a modest increase in the O2/N2 permselectivity (4.75 versus 4.67).

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Næss, Live Nova. "Pd-based Membranes for Hydrogen Separation - Membrane Structure and Hydrogen Sorption and Permeation Behavior." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20867.

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Efficient separation of hydrogen from gas mixtures is a truly enabling technology for hydrogen as an energy carrier. Palladium(Pd)-based membranes are 100% selective to hydrogen, but need to be made thin, yet without defects in order for the technology to be applicable. The motivation for this work has been to examine solubility properties and surface topography for Pd-based membranes, and further elucidate the influence these parameters have on the overall hydrogen permeation capabilities. Extremely thin, defect-free Pd-alloy membranes supplied by SINTEF Materials and Chemistry were investigated in this study.Thin Pd/Ag23wt.% free standing films of thickness 4 μm and 8 μm were inves- tigated before and after heat treatment in air at 300 C. A revealing trend of increased flux resulting from this heat treatment was observed. Surface topogra- phy studies by atomic force microscopy (AFM) showed a correlating increase in surface roughness as a result of the heat treatment. In addition, surface topogra- phy investigation was performed on a hydrogen stabilized 8 μm thick Pd/Ag23wt.% membrane. High increase in roughness was detected on feed side whereas minimal roughness alteration was observed on permeate side of the membrane. Equilibrium sorption measurements of H2 in Pd/Ag23wt.% films of various thick- nesses (2.2-10 μm) were performed at 300 C, 350 C and 400 C to the measure the film’s solubility properties. A pronounced temperature dependence was observed for all membranes, that is, high solubility at low temperatures and vice versa for high temperatures. This is consistent with theory and previously reported solu- bility results. A thickness dependence for the H2 solubility was observed in the equilibrium sorption results. Thinner membranes showed better solubility capa- bilities than the thicker ones. Surface characterization showed increasing surface roughness on growth side on these as-grown films in correspondence with augmen- tation in film thickness. The correlative surface roughness and solubility alterations related to thickness indicate a plausible membrane bulk structural dependence of the solubility.Finally, sorption equlibrium measurements on very thin Pd alloy films, ∼2 μm, of Pd/Ag23wt.%, Pd/Au5at.% and Pd/Y5at.% were carried out at 300 C, 350 C and 400 C. All three palladium-alloys showed decreasing solubility properties for in- creasing temperature. The Pd/Ag23wt.% membrane showed the highest solubility capabilities, succeeded closely by the Pd/Y5at.% membrane, while the Pd/Au5at.% membrane was not comparably capable to ad-/absorb H2 gas. This is concluded as a result of unequal lattice expansion effects the different alloying elements exert in a pure Pd lattice.The hydrogen permeation is a complex function of many parameters. In this work parameters such as, hydrogen pressure, temperature, material composition, mem- brane thickness and surface structure have demonstrated their influence on the membranes solubility and/or permeation abilities.

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Escorihuela, Roca Sara. "Novel gas-separation membranes for intensified catalytic reactors." Doctoral thesis, Universitat Politècnica de València, 2019. http://hdl.handle.net/10251/121139.

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[ES] La presente tesis doctoral se centra en el desarrollo de nuevas membranas de separación de gases, así como su empleo in-situ en reactores catalíticos de membrana para la intensificación de procesos. Para este propósito, se han sintetizado varios materiales, como polímeros para la fabricación de membranas, catalizadores tanto para la metanación del CO2 como para la reacción de síntesis de Fischer-Tropsch, y diversas partículas inorgánicas nanométricas para su uso en membranas de matriz mixta. En lo referente a la fabricación de las membranas, la tesis aborda principalmente dos tipos: orgánicas e inorgánicas. Con respecto a las membranas orgánicas, se han considerado diferentes materiales poliméricos, tanto para la capa selectiva de la membrana, así como soporte de la misma. Se ha trabajado con poliimidas, puesto que son materiales con temperaturas de transición vítrea muy alta, para su posterior uso en reacciones industriales que tienen lugar entre 250-300 ºC. Para conseguir membranas muy permeables, manteniendo una buena selectividad, es necesario obtener capas selectivas de menos de una micra. Usando como material de soporte otro tipo de polímero, no es necesario estudiar la compatibilidad entre ellos, siendo menos compleja la obtención de capas finas. En cambio, si el soporte es de tipo inorgánico, un exhaustivo estudio de la relación entre la concentración y la viscosidad de la solución polimérica es altamente necesario. Diversas partículas inorgánicas nanométricas se estudiaron para favorecer la permeación de agua a través de los materiales poliméricos. En segundo lugar, en cuanto a membranas inorgánicas, se realizó la funcionalización de una membrana de paladio para favorecer la permeación de hidrógeno y evitar así la contaminación por monóxido de carbono. El motivo por el cual se dopó con otro metal la capa selectiva de la membrana metálica fue para poder emplearla en un reactor de Fischer-Tropsch. Con relación al diseño y fabricación de los reactores, durante esta tesis, se desarrolló el prototipo de un microreactor para la metanación de CO2, donde una membrana polimérica de capa fina selectiva al agua se integró para evitar la desactivación del catalizador, y a su vez desplazar el equilibrio y aumentar la conversión de CO2. Por otro lado, se rediseñó un reactor de Fischer-Tropsch para poder introducir una membrana metálica selectiva a hidrogeno y poder inyectarlo de manera controlada. De esta manera, y siguiendo estudios previos, el objetivo fue mejorar la selectividad a los productos deseados mediante el hidrocraqueo y la hidroisomerización de olefinas y parafinas con la ayuda de la alta presión parcial de hidrógeno.
[CAT] La present tesi doctoral es centra en el desenvolupament de noves membranes de separació de gasos, així com el seu ús in-situ en reactors catalítics de membrana per a la intensificació de processos. Per a aquest propòsit, s'han sintetitzat diversos materials, com a polímers per a la fabricació de membranes, catalitzadors tant per a la metanació del CO2 com per a la reacció de síntesi de Fischer-Tropsch, i diverses partícules inorgàniques nanomètriques per al seu ús en membranes de matriu mixta. Referent a la fabricació de les membranes, la tesi aborda principalment dos tipus: orgàniques i inorgàniques. Respecte a les membranes orgàniques, diferents materials polimèrics s'ha considerat com a candidats prometedors, tant per a la capa selectiva de la membrana, així com com a suport d'aquesta. S'ha treballat amb poliimides, ja que són materials amb temperatures de transició vítria molt alta, per al seu posterior ús en reaccions industrials que tenen lloc entre 250-300 °C. Per a aconseguir membranes molt permeables, mantenint una bona selectivitat, és necessari obtindre capes selectives de menys d'una micra. Emprant com a material de suport altre tipus de polímer, no és necessari estudiar la compatibilitat entre ells, sent menys complexa l'obtenció de capes fines. En canvi, si el suport és de tipus inorgànic, un exhaustiu estudi de la relació entre la concentració i la viscositat de la solució polimèrica és altament necessari. Diverses partícules inorgàniques nanomètriques es van estudiar per a afavorir la permeació d'aigua a través dels materials polimèrics. En segon lloc, quant a membranes inorgàniques, es va realitzar la funcionalització d'una membrana de pal¿ladi per a afavorir la permeació d'hidrogen i evitar la contaminació per monòxid de carboni. El motiu pel qual es va dopar amb un altre metall la capa selectiva de la membrana metàl¿lica va ser per a poder emprar-la en un reactor de Fischer-Tropsch. En relació amb el disseny i fabricació dels reactors, durant aquesta tesi, es va desenvolupar el prototip d'un microreactor per a la metanació de CO2, on una membrana polimèrica de capa fina selectiva a l'aigua es va integrar per a així evitar la desactivació del catalitzador i al seu torn desplaçar l'equilibri i augmentar la conversió de CO2. D'altra banda, un reactor de Fischer-Tropsch va ser redissenyat per a poder introduir una membrana metàl¿lica selectiva a l'hidrogen i poder injectar-lo de manera controlada. D'aquesta manera, i seguint estudis previs, el objectiu va ser millorar la selectivitat als productes desitjats mitjançant el hidrocraqueix i la hidroisomerització d'olefines i parafines amb l'ajuda de l'alta pressió parcial d'hidrogen.
[EN] The present thesis is focused on the development of new gas-separation membranes, as well as their in-situ integration on catalytic membrane reactors for process intensification. For this purpose, several materials have been synthesized such as polymers for membrane manufacture, catalysts for CO2 methanation and Fischer-Tropsch synthesis reaction, and inorganic materials in form of nanometer-sized particles for their use in mixed matrix membranes. Regarding membranes manufacture, this thesis deals mainly with two types: organic and inorganic. With regards to the organic membranes, different polymeric materials have been considered as promising candidates, both for the selective layer of the membrane, as well as a support thereof. Polyimides have been selected since they are materials with very high glass transition temperatures, in order to be used in industrial reactions which take place at temperatures around 250-300 ºC. To obtain highly permeable membranes, while maintaining a good selectivity, it is necessary to develop selective layers of less than one micron. Using another type of polymer as support material, it is not necessary to study the compatibility between membrane and support. On the other hand, if the support is inorganic, an exhaustive study of the relation between the concentration and the viscosity of the polymer solution is highly necessary. In addition, various inorganic particles were studied to favor the permeation of water through polymeric materials. Secondly, as regards to inorganic membranes, the functionalization of a palladium membrane to favor the permeation of hydrogen and avoid carbon monoxide contamination was carried out. The membrane selective layer was doped with another metal in order to be used in a Fischer-Tropsch reactor. Regarding the design and manufacture of the reactors used during this thesis, a prototype of a microreactor for CO2 methanation was carried out, where a thin-film polymer membrane selective to water was integrated to avoid the deactivation of the catalyst and to displace the equilibrium and increase the CO2 conversion. On the other hand, a Fischer-Tropsch reactor was redesigned to introduce a hydrogen-selective metal membrane and to be able to inject it in a controlled manner. In this way, and following previous studies, the aim is to enhance the selectivity to the target products by hydrocracking and hydroisomerization the olefins and paraffins assisted by the presence of an elevated partial pressure of hydrogen.
I would like to acknowledge the Spanish Government, for funding my research with the Severo Ochoa scholarship.
Escorihuela Roca, S. (2019). Novel gas-separation membranes for intensified catalytic reactors [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/121139
TESIS

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Xue, Jian [Verfasser]. "Investigation of membrane reactors based on dense mixed-conducting ceramics for separation and catalysis process / Jian Xue." Hannover : Technische Informationsbibliothek (TIB), 2016. http://d-nb.info/1127247492/34.

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Ungerer, Maria Johanna. "Separation of tantalum and niobium by solvent extraction / M.J. Ungerer." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9850.

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Niobium (Nb) and tantalum (Ta) are found in the same group (VB) of the periodic table of elements and therefore have similar chemical properties, which is the reason why they are difficult to separate. They are usually found together in various minerals of which the most important are columbite ((Fe, Mn, Mg)(Nb, Ta)2O6) and tantalite ((Fe, Mn)(Nb, Ta)2O6). Several methods have been used to separate Nb and Ta. Most methods use very high concentrations of hydrofluoric acid (HF) and sulphuric acid (H2SO4) as the aqueous phase, tributyl phosphate (TBP) as the extractant and methyl isobutyl ketone (MIBK) as the organic phase. High extraction can be achieved, but the reagents used are hazardous. With the increasing demand of both pure Ta and Nb, as well as stricter environmental requirements, a need exists to develop a more efficient and safer technique to separate Ta and Nb. In this project the focus was on the solvent extraction (SX) of Ta and Nb with the possible application in a membrane-based solvent extraction (MBSX) process. For this purpose, eight different extractants were investigated, namely the cation exchangers di-iso-octyl-phosphinic acid (PA) and di-(2-ethylhexyl)-phosphoric acid (D2EHPA), the neutral solvating extractant 2-thenoyl-trifluoro- acetone (TTA), and the anion exchangers Alamine 336, Aliquat 336, 1-octanol, 2-octanol and 3-octanol. The extractant to metal ratio was varied from 0.1:1 to 10:1, while cyclohexane was used as diluent and 3% v/v 1-octanol was used as modifier for the organic phase. In addition, four different acids, hydrochloric acid (HCl), nitric acid (HNO3), sulphuric (H2SO4) and perchloric acid (HClO4), were used at different concentrations to determine the best combination for extraction. First, fluoride salts of Ta and Nb (Ta(Nb)F5) were tested and the optimum results showed that the highest extraction was obtained with PA and D2EHPA, irrespective of the type of acid used. Similarly, irrespective of the acid used, extraction with PA and D2EHPA increased with increasing acid concentration, followed by Alamine 336, Aliquat 336 and then TTA and the octanols. Extraction values of 97% Ta at 15 mol/dm3 and 85% Nb between 12 and 15 mol/dm3 were obtained. Although extraction of both Ta and Nb was achieved with all the acids tested, only H2SO4 showed sufficient separation (log D = 3) of the two metals in the 0 to 2 mol/dm3 acid range and 15 mol/dm3 for PA and D2EHPA, respectively. Precipitation, probably due to hydrolysis of the metals, occurred in the absence of acid when using Alamine 336, Aliquat 336 and TTA. The octanols showed the least amount of extraction of Ta and Nb, irrespective of the acid investigated. The optimum extraction was achieved with an E/M ratio of 3:1 of PA and D2EHPA as the extractant and 10 mol/dm3 H2SO4 in the aqueous phase. The NH4Ta(Nb)F6 salt solution was investigated using the optimum conditions for maximum extraction obtained from the Ta(Nb)F5 experiments, i.e. 4 mol/dm3 H2SO4 with an E/M ratio above 3:1 for the extractant PA and 4 mol/dm3 H2SO4 with an E/M ratio of 20:1 for the extractant D2EHPA. Kinetic equilibrium for PA was reached after 10 minutes and for D2EHPA after 20 minutes. The highest extraction of Ta (100%) above 3 mol/dm3 H2SO4 and Nb (54%) at 8 mol/dm3 with the highest separation factor of 4.7 with PA was achieved, followed by the 100% extraction of Ta above 5 mol/dm3 and 40% Nb at 10 mol/dm3 with the highest separation factor of 4.9 in D2EHPA. Although the aim of this study was the extraction and separation of Ta and Nb, the recovery or back extraction of the metals from the organic phase, as well as the membrane-based solvent extraction (MBSX) was briefly investigated. From the preliminary results obtained it became apparent that further research into the different aspects, including the type of stripping agent used, stripping agent concentration, effect of Ta to Nb ratio and different sources of Ta and Nb is needed to obtain the optimum conditions for the MBSX process and the subsequent recovery of Ta and Nb.
Thesis (MSc (Chemistry))--North-West University, Potchefstroom Campus, 2013.

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Ma, Rui. "Development and experimental validation of a CFD model for Pd-based membrane technology in H2 separation and process intensification." Digital WPI, 2018. https://digitalcommons.wpi.edu/etd-dissertations/544.

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Syngas production and hydrogen separation technologies are very mature, and also extremely important for energy and chemical industries. Furthermore, these processes are the most expensive elements for many applications such as hydrogen production from renewable sources. Enhancing or intensifying these very mature technologies is very challenging, but would have tremendous impact on the performance and economics of many processes. Traditional Integrated Gasification Combined Cycle (IGCC) for syngas production need to include a carbon capture process in order to regulate their carbon dioxide emission as more and more countries and regions have implemented carbon tax policy. Integration of this process with Pd membrane has long been considered a key component to make it more feasible. With these two technologies combined together, we can produce high purity hydrogen while capturing carbon dioxide and toxic gases from the syngas product. Besides, although manufacturing the membrane reactor is expensive, after considering the carbon tax factor, it actually is more economically preferable compare with the traditional Pressure Swing Adsorption (PSA) process. Most research on Pd membrane technology has been conducted at lab scale; nonetheless, the contribution of a palladium membrane technology to economic and societal development requires its commercialization, diffusion and utilization. To generate enough incentives for commercialization, it is necessary to demonstrate the scalability and robustness of the membranes in industrial settings. Consequently, a multitube membrane module suitable for IGCC system was designed and manufactured and sent to National Carbon Capture Center (NCCC) for testing. This work developed a Computational Fluid Dynamics (CFD) model for the module and validated the model utilizing the pilot-scale experimental data generated under industrial conditions. The model was then up-scaled and used to determine the intrinsic phenomena of palladium membrane scale up. This study reveals the technical/engineering requirements for the effective design of large-scale multitube membrane modules. Mass transfer limitations and concentration polarization effects were studied quantitatively with the developed model. Methods for diminishing the concentration polarization effect were proposed and tested through the simulations such as i) increasing convective forces and ii) designing baffles to create gas recirculation. For scaled-up membrane modules, mass transfer limitation is an important parameter to consider as large modules showed severe concentration polarization effects. IGCC systems produce H2 from coal combustion; other ways of H2 production include steam-reforming processes, using natural gas or bio-ethanol as the reactant. The product contains a mixture of H2, CH4, CO, CO2 and steam. Thus, steam-reforming processes are often followed by a Pressure Swing Adsorption (PSA) unit in order to obtain pure hydrogen. Palladium membrane, on the other hand, can be integrated with steam-reforming processes and achieve the simultaneous production and purification of H2 in a single unit by reaching process intensification. Higher H2 production rate can be reached by process intensification as one of the products H2 is constantly being removed. Temperature control is a very important topic in steam reforming processes, as the reaction is overall highly endothermic; although implementing an in-unit membrane improves H2 production rate, it also makes the temperature control more difficult as the reaction equilibrium is altered by the removal of one of the products H2. Hereby, an experimental study of catalytic membrane reactor (CMR) was carried out along with both isothermal and non-isothermal CFD simulations that are validated by the experimental data in order to visualize the temperature distribution inside the reactor and understand the influence of the operating conditions including temperature, pressure and the sweep gas flow patter on the permeate side.

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15

Yoo, Suk Joon. "Organic-inorganic nanocomposite membranes from highly ordered mesoporous thin films for solubility-based separations." [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1070.

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16

Shehu, Habiba. "Innovative hydrocarbons recovery and utilization technology using reactor-separation membranes for off-gases emission during crude oil shuttle tanker transportation and natural gas processing." Thesis, Robert Gordon University, 2018. http://hdl.handle.net/10059/3129.

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The increase in greenhouse gas (GHG) concentrations in the atmosphere, as well as the high rate of depletion of hydrocarbon-based resources have become a global concern. A major source of emissions of hydrocarbon vapours occur during loading and offloading operations in crude oil shuttle tanker transportation. The emitted gases have a typical composition of 60 % N2, 10 % CO2, 5% O2, 5 % C3H8, 10% CH4, 5% C2H6 and 5 % higher hydrocarbons. As a result, various methods aimed to add value to GHG to produce valuable fuels and chemical feedstock are being developed. This work incorporates the use of silica, polyurethane/zeolite and y-type zeolite membrane on an alumina support to selectively permeate methane and carbon dioxide from inert gases and higher hydrocarbons. The recovered gas is upgraded by dry reforming reactions employing rhodium/alumina membrane incorporated into a shell and tube reactor. Mixed gas permeation tests have been carried out with the permeate and feed gases sent to the online gas chromatograph (GC) equipped with a mass spectrometry (MS) detector and an automated 6-port gas sampling valve with a 30 mm HP- Plot Q column. The question is what mesoporous membrane can be highly selective for the separation of methane and carbon dioxide from inert gases and higher hydrocarbons, and what is the effect of temperature and feed gas pressure on the conversion of separated gases? Characterisation of the modified membranes was carried out using nitrogen physisorption measurements and showed the hysteresis isotherms corresponding to type IV and V, which is indicative of a mesoporous membrane. The surface area and the pore size were determined using the Barrett, Joyner, Halenda (BJH) desorption method, which showed the silica membrane had a larger surface area (10.69 m2 g-1) compared to zeolite (0.11 m2 g-1) and polyurethane/zeolite membrane (0.31 m2 g-1). Fourier Transform Infrared spectroscopy, Scanning Electron Microscope and Energy Dispersive X-ray Analysis confirmed the asymmetric deposition of silica, polyurethane, rhodium and zeolite crystals in the matrix of the alumina support. Single gas permeation tests showed that the synthesised y-type zeolite membrane at 293 K had a CH4/C3H8 selectivity of 3.11, which is higher than the theoretical value of 1.65. The permeating CH4 and C3H8 flux at 373 K and a pressure of 1 x 105 Pa was 0.31 and 0.11 mol s-1 m-2 respectively proving that zeolite has molecular sieving mechanism for separation of methane and propane. The silica membrane exhibited higher effectiveness for the separation of CO2 than the other membranes. For methane dry reforming using a supported rhodium membrane, an increase of the reaction temperature from 973 K to 1173 K showed an increase in conversion rate of CO2 and CH4 from less than 20% to over 90% while increasing the gas hourly space velocity (GHSV) did not have a noticeable effect. The study revealed the high potential of the zeolite and rhodium membrane for gas separation and dry reforming reactions concept in creating value-added carbon-based products from CO2 and CH4.

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Aspelund, Matthew Thomas. "Membrane-based separations for solid/liquid clarification and protein purification." [Ames, Iowa : Iowa State University], 2010. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3403071.

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18

Bissadi, Golnaz. "The Effect of Surfactant and Compatibilizer on Inorganic Loading and Properties of PPO-based EPMM Membranes." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23565.

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Hybrid membranes represent a promising alternative to the limitations of organic and inorganic materials for high productivity and selectivity gas separation membranes. In this study, the previously developed concept of emulsion-polymerized mixed matrix (EPMM) membranes was further advanced by investigating the effects of surfactant and compatibilizer on inorganic loading in poly(2,6-dimethyl-1,4-phenylene oxide) (PPO)-based EPMM membranes, in which inorganic part of the membranes originated from tetraethylorthosilicate (TEOS). The polymerization of TEOS, which consists of hydrolysis of TEOS and condensation of the hydrolyzed TEOS, was carried out as (i) one- and (ii) two-step processes. In the one-step process, the hydrolysis and condensation take place in the same environment of a weak acid provided by the aqueous solution of aluminum hydroxonitrate and sodium carbonate. In the two-step process, the hydrolysis takes place in the environment of a strong acid (solution of hydrochloric acid), whereas the condensation takes place in weak base environment obtained by adding excess of the ammonium hydroxide solution to the acidic solution of the hydrolyzed TEOS. For both one- and two-step processes, the emulsion polymerization of TEOS was carried out in two types of emulsions made of (i) pure trichloroethylene (TCE) solvent, and (ii) 10 w/v% solution of PPO in TCE, using different combinations of the compatibilizer (ethanol) and the surfactant (n-octanol). The experiments with pure TCE, which are referred to as a gravimetric powder method (GPM) allowed assessing the effect of different experimental parameters on the conversion of TEOS. The GPM tests also provided a guide for the synthesis of casting emulsions containing PPO, from which the EPMM membranes were prepared using a spin coating technique. The synthesized EPMM membranes were characterized using 29Si nuclear magnetic resonance (29Si NMR), differential scanning calorimetry (DSC), inductively coupled plasma mass spectrometry (ICP-MS), and gas permeation measurements carried out in a constant pressure (CP) system. The 29Si NMR analysis verified polymerization of TEOS in the emulsions made of pure TCE, and the PPO solution in TCE. The conversions of TEOS in the two-step process in the two types of emulsions were very close to each other. In the case of the one-step process, the conversions in the TCE emulsion were significantly greater than those in the emulsion of the PPO solution in TCE. Consequently, the conversions of TEOS in the EPMM membranes made in the two-step process were greater than those in the EPMM membranes made in the one-step process. The latter ranged between 10 - 20%, while the highest conversion in the two-step process was 74% in the presence of pure compatibilizer with no surfactant. Despite greater conversions and hence the greater inorganic loadings, the EPMM membranes prepared in the two-step process had glass transition temperatures (Tg) only slightly greater than the reference PPO membranes. In contrast, despite relatively low inorganic loadings, the EPMM membranes prepared in the one-step process had Tgs markedly greater than PPO, and showed the expected trend of an increase in Tg with the inorganic loading. These results indicate that in the case of the one-step process the polymerized TEOS was well integrated with the PPO chains and the interactions between the two phases lead to high Tgs. On the other hand, this was not the case for the EPMM membranes prepared in the two-step process, suggesting possible phase separation between the polymerized TEOS and the organic phase. The latter was confirmed by detecting no selectivity in the EPMM membranes prepared by the two-step process. In contrast, the EPMM membranes prepared in the one-step process in the presence of the compatibilizer and no surfactant showed 50% greater O2 permeability coefficient and a slightly greater O2/N2 permeability ratio compared to the reference PPO membranes.

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Sen, Deger. "Polycarbonate Based Zeolite 4a Filled Mixed Matrix Membranes: Preparation, Characterization And Gas Separation Performances." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609348/index.pdf.

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Developing new membrane morphologies and modifying the existing membrane materials are required to obtain membranes with improved gas separation performances. The incorporation of zeolites and low molecular-weight additives (LMWA) into polymers are investigated as alternatives to modify the permselective properties of polymer membranes. In this study, these two alternatives were applied together to improve the separation performance of a polymeric membrane. The polycarbonate (PC) chain characteristics was altered by incorporating p-nitroaniline (pNA) as a LMWA and the PC membrane morphology was modified by introducing zeolite 4A particles as fillers. For this purpose, pure PC and PC/pNA dense homogenous membranes, and PC/zeolite 4A and PC/pNA/zeolite 4A mixed matrix membranes (MMM) were prepared by solvent-evaporation method using dichloromethane as the solvent. The pNA and zeolite 4A concentrations in the casting solutions were changed between 1-5% (w/w) and 5-30% (w/w), respectively. Membranes were characterized by SEM, DSC, and single gas permeability measurements of N2, H2, O2, CH4 and CO2. They were also tested for their binary gas separation performances with CO2/CH4, CO2/N2 and H2/CH4 mixtures at different feed gas compositions. DSC analysis of the membranes showed that, incorporation of zeolite 4A particles into PC/pNA increased the glass transition temperatures, Tg, but incorporation of them to pure PC had no effect on the Tg, suggesting that pNA was a necessary agent for interaction between zeolite 4A and PC matrix. The ideal selectivities increased in the order of pure PC, PC/zeolite 4A MMMs and PC/pNA/zeolite 4A MMMs despite a loss in the permeabilities with respect to pure PC. A significant improvement was achieved in selectivities when the PC/pNA/zeolite 4A MMMs were prepared with pNA concentrations of 1 % and 2 % (w/w) and with a zeolite loading of 20 % (w/w). The H2/CH4 and CO2/CH4 selectivities of PC/pNA (1%)/zeolite 4A (20%) membrane were 121.3 and 51.8, respectively, which were three times higher than those of pure PC membrane. Binary gas separation performance of the membranes showed that separation selectivities of pure PC and PC/pNA homogenous membranes were nearly the same as the ideal selectivities regardless of the feed gas composition. On the other hand, for PC/zeolite 4A and PC/pNA/zeolite 4A MMMs, the separation selectivities were always lower than the respective ideal selectivities for all binary gas mixtures, and demonstrated a strong feed composition dependency indicating the importance of gas-membrane matrix interactions in MMMs. For CO2/CH4 binary gas mixture, when the CO2 concentration in the feed increased to 50 %, the selectivities decreased from 31.9 to 23.2 and 48.5 to 22.2 for PC/zeolite 4A (20%) and PC/pNA (2%)/zeolite 4A (20%) MMMs, respectively. In conclusion, high performance PC based MMMs were prepared by blending PC with small amounts of pNA and introducing zeolite 4A particles. The prepared membranes showed promising results to separate industrially important gas mixtures depending on the feed gas compositions.

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20

Li, Pei. "Synthesis of Room Temperature Ionic Liquid Based Polyimides for Gas Separations." University of Toledo / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1270655120.

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21

Landaverde, Alvarado Carlos Jose. "Sorption, Transport and Gas Separation Properties of Zn-Based Metal Organic Frameworks (MOFs) and their Application in CO₂ Capture." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/73214.

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Adsorption, separation and conversion of CO₂ from industrial processes are among the priorities of the scientific community aimed at mitigating the effects of greenhouse gases on the environment. One of the main focuses is the capture of CO₂ at stationary point sources from fossil fuel emissions using porous crystalline materials. Porous crystalline materials can reduce the energy costs associated with CO₂ capture by offering high adsorption rates, low material regeneration energy penalties and favorable kinetic pathways for CO₂ separation. MOFs consist of polymeric inorganic networks with adjustable chemical functionality and well-defined pores that make them ideal for these applications. The objective of this research was to test the potential for CO₂ capture on Zn-based MOFs by studying their sorption, transport and gas separation properties as adsorbents and continuous membranes. Three Zn-based MOFs with open Zn-metal sites were initially studied. Zn4(pdc)4(DMF)2•3DMF (1) exhibited the best properties for CO₂ capture and was investigated further under realistic CO₂ capture conditions. The MOF exhibited preferential CO₂ adsorption based on a high enthalpy of adsorption and selectivity of CO₂ over N₂ and CH₄. Sorption dynamics of CO₂ indicated fast adsorption and a low activation energy for sorption. Diffusion inside the pores is the rate-limiting step for diffusion, and changes in the process temperature can enhance CO₂ separation. Desorption kinetics indicated that CO₂ has longer residence times and lower activation energies for desorption than N₂ and CH₄. This suggests that the selective adsorption of CO₂ is favored. MOF/Polymer membranes were synthesized via a solvothermal method with structural defects sealed by a polymer coating. This method facilitates the permeation measurements of materials that cannot form uniform-defect-free layers. The membrane permeation of CO₂, CH₄, N₂ and H₂ exhibited a linear relation to the inverse square root of the molecular weight of the permanent gases, indicating that diffusion occurs in the Knudsen regime. Permselectivity was well-predicted by the Knudsen model with no temperature dependence, and transport occurs inside the pores of the membrane. MOF (1) exhibits ideal properties for future applications in CO₂ capture as an adsorbent.
Ph. D.

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22

Karatay, Elif. "Effect Of Preparation And Operation Parameters On Performance Of Polyethersulfone Based Mixed Matrix Gas Separation Membranes." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12610831/index.pdf.

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ABSTRACT EFFECT OF PREPARATION AND OPERATION PARAMETERS ON PERFORMANCE OF POLYETHERSULFONE BASED MIXED MATRIX GAS SEPARATION MEMBRANES Karatay, Elif M.Sc., Department of Chemical Engineering Supervisor : Prof. Dr. Levent Yilmaz Co-supervisor : Assoc. Prof. Dr. Halil Kalipç
ilar August 2009, 126 pages Membrane processes have been considered as promising alternatives to other competing technologies in gas separation industry. Developing new membrane morphologies are required to improve the gas permeation properties of the membranes. Mixed matrix membranes composing of polymer matrices and distributed inorganic/organic particles are among the promising, developing membrane materials. In this study, the effect of low molecular weight additive (LMWA) type and concentration on the gas separation performance of neat polyethersulfone (PES) membranes and zeolite SAPO-34 containing PES based mixed matrix membranes was investigated. Membranes were prepared by solvent evaporation method and annealed above the glass transition temperature (Tg) of PES in order to remove the residual solvent and erase the thermal history. They were characterized by single gas permeability measurements of H2, CO2, and CH4 as well as scanning electron microscopy (SEM), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). Various LMWAs were added to the neat PES membrane at a concentration of 4 wt %. Regardless of the type, all of the LMWAs had an anti-plasticization effect on PES gas permeation properties. 2-Hydroxy 5-Methyl Aniline, HMA, was selected among the other LMWAs for parametric study on the concentration effect of this additive. The incorporation of SAPO-34 to PES membranes increased the permeabilities of all gases with a slight loss in selectivities. However, the addition of HMA to PES/SAPO-34 membranes increased the ideal selectivities well above the ideal selectivities of PES/HMA membranes, while keeping the permeabilities of all the gases above the permeabilities of both pure PES and PES/HMA membranes.

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23

Tarun, Cynthia. "Techno-Economic Study of CO₂ Capture from Natural Gas Based Hydrogen Plants." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2837.

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As reserves of conventional crude oil are depleted, there is a growing need to develop unconventional oils such as heavy oil and bitumen from oil sands. In terms of recoverable oil, Canadian oil sands are considered to be the second largest oil reserves in the world. However, the upgrading of bitumen from oil sands to synthetic crude oil (SCO) requires nearly ten times more hydrogen (H₂) than the conventional crude oils. The current H₂ demand for oil sands operations is met mostly by steam reforming of natural gas. With the future expansion of oil sands operations, the demand of H₂ for oil sand operations is likely to quadruple in the next decade. As natural gas reforming involves significant carbon dioxide (CO₂) emissions, this sector is likely to be one of the largest emitters of CO₂ in Canada.

In the current H₂ plants, CO₂ emissions originate from two sources, the combustion flue gases from the steam reformer furnace and the off-gas from the process (steam reforming and water-gas shift) reactions. The objective of this study is to develop a process that captures CO₂ at minimum energy penalty in typical H₂ plants.

The approach is to look at the best operating conditions when considering the H₂ and steam production, CO₂ production and external fuel requirements. The simulation in this study incorporates the kinetics of the steam methane reforming (SMR) and the water gas shift (WGS) reactions. It also includes the integration of CO₂ capture technologies to typical H₂ plants using pressure swing adsorption (PSA) to purify the H₂ product. These typical H₂ plants are the world standard of producing H₂ and are then considered as the base case for this study. The base case is modified to account for the implementation of CO₂ capture technologies. Two capture schemes are tested in this study. The first process scheme is the integration of a monoethanolamine (MEA) CO₂ scrubbing process. The other scheme is the introduction of a cardo polyimide hollow fibre membrane capture process. Both schemes are designed to capture 80% of the CO₂ from the H₂ process at a purity of 98%.

The simulation results show that the H₂ plant with the integration of CO₂ capture has to be operated at the lowest steam to carbon (S/C) ratio, highest inlet temperature of the SMR and lowest inlet temperatures for the WGS converters to attain lowest energy penalty. H₂ plant with membrane separation technology requires higher electricity requirement. However, it produces better quality of steam than the H₂ plant with MEA-CO₂ capture process which is used to supply the electricity requirement of the process. Fuel (highvale coal) is burned to supply the additional electricity requirement. The membrane based H₂ plant requires higher additional electricity requirement for most of the operating conditions tested. However, it requires comparable energy penalty than the H₂ plant with MEA-CO₂ capture process when operated at the lowest energy operating conditions at 80% CO₂ recovery.

This thesis also investigates the sensitivity of the energy penalty as function of the percent CO₂ recovery. The break-even point is determined at a certain amount of CO₂ recovery where the amount of energy produced is equal to the amount of energy required. This point, where no additional energy is required, is approximately 73% CO₂ recovery for the MEA based capture plant and 57% CO₂ recovery for the membrane based capture plant.

The amount of CO₂ emissions at various CO₂ recoveries using the best operating conditions is also presented. The results show that MEA plant has comparable CO₂ emissions to that of the membrane plant at 80% CO₂ recovery. MEA plant is more attractive than membrane plant at lower CO₂ recoveries.

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White, Jeremy Clayton. "Sensing, Separations and Artificial Photosynthetic Assemblies Based on the Architechture of Zeolite Y and Zeolite L." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1237641440.

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25

Wu, Hong. "Sulfate radical based ceramic catalytic membranes for water treatments." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2020. https://ro.ecu.edu.au/theses/2382.

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The discharge of antibiotics into natural aquatic environment without proper treatments results in the propagation of antibiotics-resistant strains. Effective remediation technologies are therefore urged to remove those emerging contaminants from water. However, antibiotics are difficult to be degraded through a traditional biological treatment because they would deactivate the effective bacteria used in the process. Advanced oxidation processes (AOPs) using highly reactive oxygen species (ROS) such as hydroxyl radicals ( OH) and sulfate radicals (SO4 •− • ) have been widely employed as an efficient way for antibiotics degradation owing to the high oxidation ability, non-selectivity and low cost. However, the recovery of the suspended catalysts after use is the biggest obstacle for the wide application. Meantime, membrane separation has also been extensively applied as a promising wastewater treatment technology with the advantages of long-term operation, low energy consumption and high yield of production. The membrane fouling is, however, a critical issue restricting the widespread application of membrane. For addressing above-mentioned issues, with extensive technological and scientific endeavours, this PhD study focused on the development of novel integration technology of AOPs and membrane separation for antibiotics degradation. In this research, heterogeneous AOPs processes coupled with independent membrane separation unit for suspended catalysts recovery were studied. Moreover, metal oxide based-catalytic membrane for concurrent AOPs and membrane separation were investigated. Firstly, boron, nitrogen co-doped carbon nanotubes supported FeOOH (FeOOH@BNC) was synthesized for the degradation of sulfamethoxazole (SMX) by Fenton-like reaction. The as-synthesized FeOOH@BNC showed an excellent performance in SMX removal (Chapter 3). Secondly, boron, nitrogen co-doped nanotubes (BNC) were developed. The BNC nanotubes with a high specific area, abundant active sites, and controllable N–B–C structures demonstrated prominent peroxymonosulfate (PMS) activation ability towards 4-hydroxylbenzoic acid (HBA) degradation (Chapter 4). It was also found that both FeOOH@BNC and BNC suspended catalysts in the treated solution can be well recovered via membrane filtration (Chapter 3 and 4). Finally, two metal oxide-based catalytic ceramic membranes (Co3O4@CM and MnO2@CM) were prepared via a simple one-step ball-milling method with a high temperature sintering. The as-prepared Co3O4@CM and MnO2@CM composite catalytic membranes were characterized and tested for the degradation of aqueous HBA solution by SR-AOPs procedure. It was found that the composite membranes showed excellent HBA removal efficiencies, good reusability and high anti-fouling performances (Chapter 5 and 6). Mechanistic studies, e.g. materials chemistry, generation of reactive radicals, and degradation pathways, were also carried out. The developed catalysts, catalyst membranes, and the combined processes as well as the mechanistic studies are expected to provide significant contributions in terms of both technology and scientific knowledge to remediation of emerging contaminants.

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26

Zhang, Wenrui. "Synthesis and Characterization of Toughened Thermally Rearranged Polymers, Poly(2,6-Dimethylphenylene-oxide) Based Copolymers and Polymer Blends for Gas Separation Membranes." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/86363.

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Thermally rearranged (TR) polymers have outstanding gas separation properties, but are limited in their industrial application due to being mechanically brittle. A series of low volume fraction of a poly(arylene ether sulfone) (PAES) block was introduced into the TR precursor polyhydroxyimide (PI) chain to improve mechanical properties without compromising gas transport properties. The multiblock copolyhydroxyimide incorporated the PAES in systematically varied amounts and copolymerized it with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride and 3,3’-dihydroxy-4,4’-diaminobiphenyl. Before thermal rearrangement, the PI-co-PAES precursors exhibited much more improved mechanical properties (tensile stress and strain at break) than those of homo polyimide precursor. After thermal rearrangement, tensile stress and strain at break of all TR copolymers decreased comparing to their corresponding precursors, but improved comparing to the homo TR polymer. Poly(phenylene oxide) (PPO) based copolymers (Chapter 4) and polymer blends (Chapter 5) were also studied for use as gas separation membranes. The polymer materials were cast into films, then crosslinked in the solid state with UV light. The ketone and benzylic methyl groups crosslinked upon exposure to UV light. For the study of PPO copolymers, copolymers were prepared by polycondensation of a difunctional PPO oligomer with 4,4’-difluorobenzophenone or 1,3-bis(4-fluorobenzoyl)benzene respectively. This study offers a means for fabrication of membrane films, fibers or composites, as well as tuning of gas transport properties through crosslinking in the solid state. While for the study of PPO polymer blends, PPO polymers with Mn’s from 2000-22,000 g/mole were synthesized and blended with a poly(arylene ether ketone) derived from bisphenol A and difluorobenzophenone (BPA-PAEK). The crosslinked blends had improved gas selectivities over their linear counterparts. The 90/10 wt/wt 22k PPO/BPA PAEK crosslinked blends gained the most O2/N2 selectivity and maintained a high permeability.
Ph. D.

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27

Zhang, Chengda. "SYNTHESES OF PEG/ALKYL-BASED IMIDAZOLIUM/PYRIDINIUM IONIC LIQUIDS AND APPLICATIONS ON H2S ABSORPTION& SYNTHESES OF POLYSULFONE BASED FUNCTIONALIZED IMIDAZOLIUM IONIC POLYMERS AND APPLICATIONS ON GAS SEPARATION." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1797.

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The synthesis method for PEG/alkyl-based imidazolium/pyridinium ionic liquids was studied. Four steps were used to fabricate the membranes: polymerization, chloromethylation, linkage of the polymers with the pendent groups and membrane cast. Permeabilities and CO2/N2 selectivity of two membranes were examined and each showed remarkable CO2/N2 selectivity. CO2 permeability of the [PSM-MIM][Cl] membrane is better than that of the [PSM-MEIM][Cl] membrane, which is due to the steric hindrance of the methoxyethyl group. The syntheses of PEG/alkyl-based imidazolium/pyridinium ionic liquids (IL) were studied. PEG-based ILs were demonstrated to have better H2S solubilities than the alkyl-based ILs. H2S solubilities of the imidazolium ILs and pyridinium ILs were compared. The anion effects on H2S solubilities have been investigated, while the temperature effects on H2S solubilities will need to be studied in the near future.

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28

Cakal, Ulgen. "Natural Gas Purification By Zeolite Filled Polyethersulfone Based Mixed Matrix Membranes." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611206/index.pdf.

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This research investigates the effect of feed composition on the separation performance of pure polyethersulfone (PES) and different types of PES based mixed matrix membranes (MMMs) in order to develop high performing membranes for CO2/CH4 separation. MMMs were prepared by solvent evaporation method using PES as the polymer matrix with SAPO-34 particles as fillers, and 2-hydroxy 5-methyl aniline (HMA) as the low molecular weight additive. Four types of membranes were used throughout the study, namely pure PES membrane, PES/HMA (4, 10%w/w) membrane, PES/SAPO-34 (20%w/w) MMM, PES/SAPO-34 (20%w/w)/HMA (4, 10%w/w) MMM. The effect of CO2 composition on the performance of the membranes was investigated in detail with a wide feed composition range changing between 0 and 100%. In addition to separating CO2/CH4 binary gas mixtures, the separation performances of these membranes were determined by measuring single gas permeabilities at 35º
C, with a feed pressure of 3 bar. Moreover, the membranes were characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermal gravimetric analyzer (TGA). The separation selectivities of all types of membranes generally observed to be independent of feed composition. The composition independency of these membranes eliminates the need of investigating at which feed gas composition the prepared membranes are best performing for practical applications. PES/SAPO-34/HMA MMMs with HMA loading of 10% and SAPO-34 loading of 20% demonstrated the highest separation selectivity of about 40, and the ideal selectivity of 44, among the used membranes.

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Gonciaruk, Aleksandra. "Graphene and triptycene based porous materials for adsorption applications." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/graphene-and-triptycene-based-porous-materials-for-adsorption-applications(932755b9-1600-4f64-8683-00844645a58b).html.

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There were three main driving forces behind this thesis: global concern over climate change mainly due to uncontrolled carbon dioxide (CO2) emissions, the excitement over the discovery of graphene and its versatile potential, and the potential to design three-dimensional (3D) or two-dimensional (2D) structures, in our case using unique triptycene molecule. We examined two polymeric materials for CO2 adsorption and suggested simple design of disordered carbons suitable for gas adsorption studies. The approach in each task was to examine structural and adsorption properties of materials using detailed atomistic modelling employing Monte Carlo and Molecular Dynamics techniques and where possible provide experimental measurements to validate the simulations. The thesis is presented as a collection of papers and the work can be divided into three independent projects. The aim of the first project is to utilize graphene as an additive in polymer composites in order to increase separation between the polymer chains increasing available surface area. The matrix used is a polymer of intrinsic microporosity (PIM-1), which possess large surface area and narrow nano-sized ( > 2nm) pore distribution attractive for gas separation membrane applications. Adding a filler can reduce aging of the polymer, and enhance permeability across the membrane, often to the expense of loosing selectivity. Therefore, we investigated the packing of PIM-1 chains in presence of discrete 2D graphene platelets and 3D graphene-derived structures and its effect on composite structure and adsorption properties. We found that additives do not alter structural polymer properties at the molecular level preserving the same adsorption capacity and affinity. Potential permeability increase would benefit from the retention of selectivity in the material. Building on design philosophy of materials with intrinsic microporosity we continued further investigation of 3D graphene-derived structures. The idea is that highly concave molecules or polymer chains pack inefficiently creating microporous materials with sufficient surface area for gas adsorption. 3D propeller-like structures were derived from graphene arms connected through the rigid triptycene and other types of cores. The resulting structures created a large amount of micropores and showed similar CO2/CH4 selectivity to activated carbons reported in the literature. It was shown that rigid triptycene core leads to more open structures. The model was also applied to model commercially available activated carbon to predict n- perfluorohexane adsorption. The fitting to experimental structural information proved to be challenging due to trial and error nature of the approach. Nevertheless, the simple packing procedure and diverse structure design have a great potential to serve as a virtual model for porous carbons that possess pore complexity and does not require any previous experimental data to be build on. The last project concerns CO2 adsorption and selectivity over CH4 and N2 in recently reported triptycene-based polymer. The triptycene shape polymer can form a porous 2D network that can be exfoliated into free-standing sheets and potentially used as a membrane. Sheets stack in the bulk material forming anisotropic channel pores. Additionally it contains fluoro- functional groups, which are known to have a high CO2 affinity. We explored pore structure and chemistry of stacked material for gas adsorption and predicted comparable capacity and CO2 selectivity to other microporous covalent materials such as activated carbons and PIMs. The CH4/N2 selectivity was similar to currently most selective material belonging to MOF family. We showed that fluoro-group have a positive effect on CO2 affinity, however predictions are sensitive to the charges of fluorine atoms assigned by different methods.

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30

Lin, Chien-Cheng, and 林建程. "Fabrication of Palladium-based Alloy Membrane and Cermet Membrane for Hydrogen Separation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/36955360646747466363.

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碩士
國立交通大學
材料科學與工程學系所
101
We fabricate a Pd-based alloy membrane on a porous alumina tube via a sequential electroless deposition technique. The membrane enables the separation of hydrogen from a mixture of hydrogen and carbon dioxide at elevated temperature. A buffer layer is adopted to reduce the surface roughness. The calcination temperature causes the alumina to form different phases, among which the γ-Al2O3 is suitable for the electroless deposition process. During the electroless deposition process, all the metals except copper are homogeneously formed. The permeability of H2 and the selectivity of H2/CO2 are very low because of the intrinsic leakage. We also fabricate a cermet composite membrane composed of a hydrogen transporting metal (Pd) and a proton-conducting ceramic (BaCe0.4Zr0.4Gd0.1Dy0.1O3-x, BCZGD). The BCZGD proton-conducting perovskite powders are synthesized via a combustion method. The Pd-BCZGD cermet membrane is then fabricated by pressing a mixture of the Pd and BCZGD powders at equal volume, followed by sintering at 1450°C for 15 h in air. The properties of the Pd-BCZGD membrane are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal gravimetric analysis (TGA). The element map on the membrane surface and cross-section demonstrate that the Pd is uniformly-distributed in the perovskite phase. The XRD indicates characteristic peaks to metallic Pd and BCZGD perovskite phases. TGA confirms that the cermet membrane is chemically stable against CO2. Lastly, the flux from a gas chromatography (GC) are determined as a function of temperature and under different feed gas hydrogen pressures. The leakage rate of He through the cermet membrane is only 0.01 mol% so the separation ratio of H2 and CO2 is large.

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31

Alhazmi, Abdulrahman. "Tröger’s Base Ladder Polymer for Membrane-Based Hydrocarbon Separation." Thesis, 2017. http://hdl.handle.net/10754/623653.

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The use of polymeric membranes for natural gas separation has rapidly increased during the past three decades, particularly for carbon dioxide separation from natural gas. Another valuable application is the separation of heavy hydrocarbons from methane (fuel gas conditioning), more importantly for remote area and off-shore applications. A new potential polymeric membrane that might be utilized for natural gas separations is a Tröger’s base ladder polymer (PIM-Trip-TB-2). This glassy polymeric membrane was synthesized by the polymerization reaction of 9, 10-dimethyl-2,6 (7) diaminotriptycene with dimethoxymethane. In this research, the polymer was selected due to its high surface area and highly interconnected microporous structure. Sorption isotherms of nitrogen (N2), oxygen (O¬2), methane (CH4), carbon dioxide (CO2), ethane (C2H6), propane (C3H8), and n-butane (n-C4H10) were measured at 35 °C over a range of pressures using a Hiden Intelligent Gravimetric Analyzer, IGA. The more condensable gases (C2H6, CO2, C3H8, and n-C4H10) showed high solubility due to their high affinity to the polymer matrix. The permeation coefficients were determined for various gases at 35 °C and pressure difference of 5 bar via the constant-pressure/variable-volume method. The PIM-Trip-TB-2 film exhibited high performance for several high-impact applications, such as O2/N2, H2/N2 and H2/CH4. Also, physical aging for several gases was examined by measuring the permeability coefficients at different periods of time. Moreover, a series of mixed-gas permeation tests was performed using 2 vol.% n-C4H10/98 vol.% CH4 and the results showed similar transport characteristics to other microporous polymers with pores of less than 2 nm. The work performed in this research suggested that PIM-Trip-TB-2 is suitable for the separation of: (i) higher hydrocarbons from methane and (ii) small, non-condensable gases such as O2/N2 and H2/CH4.

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32

Damle, Shilpa C. "Membrane based separations of carbon dioxide and phenol under supercritical conditions." Thesis, 2004. http://hdl.handle.net/2152/1912.

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33

Yuan, Shao Hsuan, and 袁紹軒. "Core-Shell Zeolitic Imidazolate Framework Based Mixed Matrix Membrane for Gas Separation." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/7s6h2p.

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碩士
國立中央大學
化學工程與材料工程學系
107
Zeolitic imidazolate framework (ZIF) is a promising material in membrane technology for gas separation. In our work, ZIF-8 and ZIF-67 were synthesized in the form of core-shell structure (ZIF-67@ZIF-8) by the seed mediated growth method. ZIF-67@ZIF-8 nanocrystals present higher surface area, gas uptake and thermal stability in comparison with the core (ZIF-67). ZIF fillers were added into 6FDA-DAM with the proper solvent to fabricate mixed matrix membranes (MMMs). In order to realize the mechanism of the core-shell structure, the preparation of membrane plays an important role to obtain defect-free nanocomposite by the colloidal solution, priming method and annealing treatment. The well-dispersed core-shell ZIFs nanocomposites provide more microporous pathways for gas separation. The result of MMMs demonstrates a remarkable hydrogen permeability and the slight enhancement of selectivities against N2 and CH4. The highest performance of ZIF-67@ZIF-8 MMM surpasses the 2008 Robeson’s upper bound for H2/CH4. This effect of core-shell structure can be observed in glassy as well as rubbery polymer.

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34

Wang, Shunyu. "A study of a novel membrane-based liquid-gas contactor /." 2005.

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35

Chih-Lung, Chen, and 陳志隆. "The Pore Structure and the Separation Properties of Silicon-Carbon Based Inorganic Membrane." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/34578132918467293475.

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36

(5930732), Xiaoli Liu. "Performance analysis for a membrane-based liquid desiccant air dehumidifier: experiment and modeling." Thesis, 2019.

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Liquid desiccant air dehumidification (LDAD) is a promising substitute for the conventional dehumidification systems that use mechanical cooling. However, the LDAD system shares a little market because of its high installation cost, carryover problem, and severe corrosion problem caused by the conventional liquid desiccant. The research reported in this thesis aimed to address these challenges by applying membrane technology and ionic liquid desiccants (ILDs) in LDAD. The membrane technology uses semi-permeable materials to separate the air and liquid desiccants, therefore, the solution droplets cannot enter into the air stream to corrode the metal piping and degrade the air quality. The ILDs are synthesized salts in the liquid phase, with a large dehumidification capacity but no corrosion problems. In order to study the applicability and performance of these two technologies, both experimental and modeling investigations were made as follows.

In the study, experimental researches and existing models on the membrane-based LDAD (MLDAD) was extensively reviewed with respects of the characteristics of liquid desiccants and membranes, the module design, the performance assessment and comparison, as well as the modeling methods for MLDAD.

A small-scale prototype of the MLDAD was tested by using ILD in controlled conditions to characterize its performance in Oak Ridge National Lab. The preliminary experimental results indicated that the MLDAD was able to dehumidify the air and the ILD could be regenerated at 40 ºC temperature. However, the latent effectiveness is relatively lower compared with conventional LDAD systems, and the current design was prone to leakage, especially under the conditions of high air and solution flow rates.

To improve the dehumidification performance of our MLDAD prototype, the two-dimensional numerical heat and mass transfer models were developed for both porous and nonporous membranes based on the microstructure of the membrane material. The finite element method was used to solve the equations in MATLAB. The models for porous and nonporous membranes were validated by the experimental data available from literature and our performance test, respectively. The validated models were able to predict the performance of the MLDAD module and conduct parametric studies to identify the optimal material selection, design, and operation of the MLDAD.

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37

Damle, Shilpa C. Johnston Keith P. Koros William J. "Membrane based separations of carbon dioxide and phenol under supercritical conditions." 2004. http://repositories.lib.utexas.edu/bitstream/handle/2152/1912/damlesc042.pdf.

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38

Li, Meng-Han, and 李孟翰. "Electroless Deposition of Palladium-based Alloy Membrane on an Alumina Support for Hydrogen Separation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/58281581332870732235.

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碩士
國立交通大學
材料科學與工程學系
100
In this work, we attempt to fabricate a Pd-based alloy membrane on an alumina support via a sequential electroless deposition technique. The membrane enables the separation of hydrogen from a mixture of hydrogen and carbon dioxide at elevated temperature. We use commercial ceramic paste as a sealing material in which the debindering and sintering temperatures are identified as 600 and 1150 degree Celsius, respectively. From GC results, after proper sealing we attain desirable air tightness at 600 degree Celsius. The electroless deposition is conducted on a flat alumina disk initially in order to determine suitable processing parameters for targeted alloy composition. Materials characterization such as phase, composition, and morphology are carried out. The PdAg and PdAgCu membranes show homogenous single phase, and the surface maintains nicely after annealing at 600 degree Celsius. However, the PdAgCuNi membrane behaves differently because of phase separation between Cu and Ni. The roughness is found to increase in PdAgCu and PdAgCuNi as the deposition progresses, a fact that is attributed to the homogenous nucleation of Cu during electroless plating. The expected ratio for Pd-based alloy membrane can be controlled and estimated after careful weight determination. In addition, we successfully prepare PdAgCuNi alloy membrane on a porous alumina tube after proper sealing and the hydrogen permeation test will be performed shortly.

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39

Yung-Liang, Lai, and 賴勇良. "Removal of Toxic Dissolved Organics from Aqueous Streams Using Surfactant-Based Membrane Separation System." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/03103228499051560957.

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碩士
國立屏東科技大學
環境工程與科學系
88
Industrial wastewater often contains high toxic organic compounds. Waste Streams containing high concentration of those organic compounds may be harmful to the environment. Traditional treatment methods used to separate soluble organics from aqueous streams require phase change which results in high energy requirement. Those methods including ion complexation, adsorption, ion exchange, or chemical oxidation are usually followed by some combination of filtration, extraction, or distillation. Those methods have many disadvantages and cost much money. Therefore, economic purification may becomes a requirement in the future development of many industrial process. Micellar-enhanced ultrafiltration （MEUF）is becoming increasingly important for industrial application. This technology generally requires less energy than traditional methods, and has the advantage to utilize the surfactants that are innocuous and low toxicity. The objective of this study concentrates on two experimential sections. The first study is focus on the feasibility of efficient surfactant/organics molar ratio (S/O ratio) and membrane sizes to separate of organic solutes（phenol and o-cresol）from an aqueous stream using cationic surfactant（CPC）.The second study is to investigate the adsorption mechanism using mass balance and binding isotherm to determine the binding capacity and separation efficiency. The results from the ultrafiltration experiments show that （1）pure CPC（20mM） micelles is effectively retained by membrane pore size of MWCO=1K, 5K, 10K, the rejection ratio is ranged from 92~96% ;（2）CPC is not effectively retained by membrane at S/O ratio =1, because most of CPC exists in monomer form,the rejection ratio is ranged from 20~30% ;（3）the rejection ratio increased with increasing surfactant concentration, S/O ratio = 10 is optimal operating condition ;（4）the rejection of pure phenol and o-cresol can not be retained by three different membrane pore size ;（5）the rejection ratio of organics increased with S/O ratio ; （6）the rejection of o-cresol is higher than that of phenol at the same S/O ratio,because o-cresol has a hydrophobic methyl group which can increase its solubility in micelles ;（7）in diafiltration experiments, the rejection of phenol and o-cresol is 23.4 % and 29.7 %, respectively ; and (8)binding ratio of o-cresol (4.5) is greater than phenol (0.8).

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40

Tsai, Yen-Chang, and 蔡延璋. "Synthesis of Dense Palladium-based Cermet Membrane for H2 and CO2 Separation at Elevated Temperature." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/65429592605676242204.

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碩士
國立交通大學
材料科學與工程學系所
103
A cermet composite consisting of palladium and BaCe0.4Zr0.4Gd0.1Dy0.1O3-x (BCZGD) is fabricated by mixing palladium and BCZGD powders in a ball mill, followed by pressing and sintering at 1450°C for 24 h in air. The Pd-BCZGD cermet demonstrates impressive hydrogen permeation flux in a mixture of hydrogen and carbon dioxide at elevated temperature. Material characterization including scanning electron microscopy (SEM), X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA) are performed. XRD patterns indicate pure phases of fcc palladium and perovskite BCZGD. SEM images and element mapping suggest a homogeneous mixture of cermet without noticeable defect and phase segregation. TGA results confirm stability of the cermet against carbon dioxide without chemical decomposition. The hydrogen permeation flux is determined via a gas chromatography from 400 to 700°C at various hydrogen concentration gradients. We record a hydrogen flux of 1.25 cm3 min-1 cm-2 in 50% hydrogen and 50% carbon dioxide at 700°C, with a selectivity of H2/CO2 approaching infinity.

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41

Wei-ZeSyu and 許偉澤. "Numerical study on hydrogen permeation and polarization in Pd-based membrane tubes for hydrogen separation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/50151202351021681138.

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碩士
國立成功大學
機械工程學系碩博士班
100
The influence of concentration polarization and separation efficiency for hydrogen through palladium-based membrane was investigated by simulation. According the numerical results, how the concentration polarization affecting H2 permeation and finding out the optimized conditions to refer to experiment are mentioned in this study. There are two parts in this study. In the first part of this research, a model base on the experimental equipment is constructed. Four important parameters which are the pressure difference, H2 molar fraction, Reynolds number, and membrane permeance affecting H2 permeation proceed a extensive survey. The predictions indicate that increasing pressure difference or membrane permeance facilitates H2 permeation rate; concentration polarization is thus triggered. Alternatively, when Reynolds number or H2 molar fraction decreases along with a higher permeance, the deviation of plug flow reactor (PFR) from continuous stirred tank reactor (CSTR) grows, even though H2 permeation rate declines. From the obtained results, it is concluded that the H2 permeation rate can be predicted by Sieverts’ law if the H2 permeation ratio is no larger than 30%. In the second part of this research, the sweep gas is added into the membrane tube to seek the influences of flow pattern and sweep gas on hydrogen permeation and polarization. The predicted results suggest that the counter-current mode are able to give the better performance of hydrogen separation compared to the co-current mode, and complete hydrogen recovery can be achieved if the flow rate of feed gas is low to a certain extent. However, lower flow rates of feed gas and sweep gas will trigger serious concentration polarization on the membrane surface. The transport of feed gas into the membrane tube from the lumen side or the shell side is flexible. The optimum Reynolds number of sweep gas in accordance with the Reynolds number of feed gas can be correlated by an arc tangential function which is able to provide a reference for the operation of hydrogen separation by controlling sweep gas.

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42

LI, Yu-Min, and 李煜閔. "Synthesis, characterization of Solvent-based and Water-based electroactive polyurethane elastomer membrane and their application in Gas separation and pervaporation." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/57vv4u.

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碩士
中原大學
化學研究所
102
In this study, the electroactive amine-capped aniline trimer (ACAT) was incorporated into solvent-based and waterborne polyurethane (PU) to give several electroactive PU membranes, which with high mechanical strength, better air permeability, simultaneously. For the synthesis of ACAT, aniline was reacted with 4,4-Aminodiphenylamine followed by characterized by Fourier transform infrared spectroscopy (FTIR), proton-nuclear magnetic resonance (1H NMR) spectroscopy and mass spectrometry (ESI-TOF-MASS). Subsequently, for the preparation of electroactive waterborne polyurethane (WPU) membrane, WPU pre-polymer was first prepared by reacting poly-ε-caprolactone (PCL) with 2,2-dimethylol propionic acid (DMPA) and cyclohexyl isocyanate (H12DMI). Secondly, the electroactive WPU was prepared by incorporating with ACAT. Moreover, for the preparation of electroactive solvent-based polyurethane membrane (SPU), the polyurea acrylate prepolymer was prepared by using isophorone diisocyanate (IPDI) reacting with a polyether diol (PTMG), following by introducing the ACAT into polymer to yield the electroactive SPU membrane. Mechanical strength of electroactivity, optical properties, thermal properties, surface wettability and permeability of PU membrane was studied by using a circulating apparatus (CV), a universal tensile testing machine, differential scanning calorimetry (DSC), thermal gravimetric analysis (TGA), contact angle meter (contact angle) and gas permeability analyzer (GPA), respectively. It should be noted that the selectivity of pervaporation for electroactive WPU and SPU membrane was increased as compared to that of non-electroactive PU membranes.

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43

Dumee, Ludovic. "Carbon-nanotube-based membranes for water desalination by membrane distillation." Thesis, 2011. https://vuir.vu.edu.au/19366/.

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This work investigates ways to fabricate composite macro-structures made of carbon nanotubes in combination with polymers and metals to enhance membrane lifespan and performance. Carbon nanotube Buckypapers were used as a template to engineer composite structures. The new materials have been thoroughly characterized for their thermal, structural and performance characteristics. The permeation and adsorption of gas and water vapor, as well as the membranes’ performance in desalination by direct contact membrane distillation, were tested and compared with polymeric benchmarks.

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44

Wang, Chun-Ju, and 王俊茹. "The separation of PBI based on molecular weight&The effect of molecular weight upon PBI membrane properties." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/91944167594103797582.

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碩士
元智大學
化學工程與材料科學學系
98
The effect of molecular weight upon polybenzimidazole (PBI) membrane properties has been investigated. PBI was synthesized by polymerization of 3,3-diaminobenzidine and isophthalic acid with a molar ratio of 1:1. The structure of PBI was determined by FTIR. The obtained polymer was then fractionated by dissolving in various solvent at temperatures 30◦C The weight-averaged molecular weights of 1.24×104, 8.85×104, 2.91×105, and 3.81×105 g /mol were obtained. PBI membranes have been prepared with different molecular weights. The acid uptake and mechanical strength were studied for the pristine PBI membranes and PBI membranes before and after being doped with phosphoric acid. The acid doping level of PBI membrane was increased with increasing the molecular weight PBI. High molecular weights of the PBI membrane improve the mechanical strength. After being doped with phosphoric acid, the mechanical strength of the membranes became poor.

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45

Chowdhury, Mohammad Hassan Murad. "Simulation, Design and Optimization of Membrane Gas Separation, Chemical Absorption and Hybrid Processes for CO2 Capture." Thesis, 2011. http://hdl.handle.net/10012/6430.

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Coal-fired power plants are the largest anthropogenic point sources of CO2 emissions worldwide. About 40% of the world's electricity comes from coal. Approximately 49% of the US electricity in 2008 and 23% of the total electricity generation of Canada in 2000 came from coal-fired power plant (World Coal Association, and Statistic Canada). It is likely that in the near future there might be some form of CO2 regulation. Therefore, it is highly probable that CO2 capture will need to be implemented at many US and Canadian coal fired power plants at some point. Several technologies are available for CO2 capture from coal-fired power plants. One option is to separate CO2 from the combustion products using conventional approach such as chemical absorption/stripping with amine solvents, which is commercially available. Another potential alternative, membrane gas separation, involves no moving parts, is compact and modular with a small footprint, is gaining more and more attention. Both technologies can be retrofitted to existing power plants, but they demands significant energy requirement to capture, purify and compress the CO2 for transporting to the sequestration sites. This thesis is a techno-economical evaluation of the two approaches mentioned above along with another approach known as hybrid. This evaluation is based on the recent advancement in membrane materials and properties, and the adoption of systemic design procedures and optimization approach with the help of a commercial process simulator. Comparison of the process performance is developed in AspenPlus process simulation environment with a detailed multicomponent gas separation membrane model, and several rigorous rate-based absorption/stripping models. Fifteen various single and multi-stage membrane process configurations with or without recycle streams are examined through simulation and design study for industrial scale post-combustion CO2 capture. It is found that only two process configurations are capable to satisfy the process specifications i.e., 85% CO2 recovery and 98% CO2 purity for EOR. The power and membrane area requirement can be saved by up to 13% and 8% respectively by the optimizing the base design. A post-optimality sensitivity analysis reveals that any changes in any of the factors such as feed flow rate, feed concentration (CO2), permeate vacuum and compression condition have great impact on plant performance especially on power consumption and product recovery. Two different absorption/stripping process configurations (conventional and Fluor concept) with monoethanolamine (30 wt% MEA) solvent were simulated and designed using same design basis as above with tray columns. Both the rate-based and the equilibrium-stage based modeling approaches were adopted. Two kinetic models for modeling reactive absorption/stripping reactions of CO2 with aqueous MEA solution were evaluated. Depending on the options to account for mass transfer, the chemical reactions in the liquid film/phase, film resistance and film non-ideality, eight different absorber/stripper models were categorized and investigated. From a parametric design study, the optimum CO2 lean solvent loading was determined with respect to minimum reboiler energy requirement by varying the lean solvent flow rate in a closed-loop simulation environment for each model. It was realized that the success of modeling CO2 capture with MEA depends upon how the film discretization is carried out. It revealed that most of the CO2 was reacted in the film not in the bulk liquid. This insight could not be recognized with the traditional equilibrium-stage modeling. It was found that the optimum/or minimum lean solvent loading ranges from 0.29 to 0.40 and the reboiler energy ranges from 3.3 to 5.1 (GJ/ton captured CO2) depending on the model considered. Between the two process alternatives, the Fluor concept process performs well in terms of plant operating (i.e., 8.5% less energy) and capital cost (i.e., 50% less number of strippers). The potentiality of hybrid processes which combines membrane permeation and conventional gas absorption/stripping using MEA were also examined for post-combustion CO2 capture in AspenPlus®. It was found that the hybrid process may not be a promising alternative for post-combustion CO2 capture in terms of energy requirement for capture and compression. On the other hand, a stand-alone membrane gas separation process showed the lowest energy demand for CO2 capture and compression, and could save up to 15 to 35% energy compare to the MEA capture process depending on the absorption/stripping model used.

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46

Gu, Zu-Chiang, and 谷祖強. "Synthesis and properties of crosslinkable phosphinated low-dielectric polyphenylene oxide for high frequency communication and lignin-based high rigid gas separation membrane." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/28361880909374513783.

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47

(8715135), Siddhi-Santosh Hate. "DISSOLUTION AND MEMBRANE MASS TRANSPORT OF SUPERSATURATING DRUG DELIVERY SYSTEMS." Thesis, 2020.

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Supersaturating drug delivery systems are an attractive solubility enabling formulation strategy for poorly soluble drugs due to their potential to significantly enhance solubility and hence, bioavailability. Compendial dissolution testing is commonly used a surrogate for assessing the bioavailability of enabling formulations. However, it increasingly fails to accurately predict in vivo performance due its closed-compartment characteristics and the lack of absorptive sink conditions. In vivo, drug is continually removed due to absorption across the gastrointestinal membrane, which impacts the luminal concentration profile, which in turn affects the dissolution kinetics of any undissolved material, as well as crystallization kinetics from supersaturated solutions. Thus, it is critical to develop an improved methodology that better mimics in vivo conditions. An enhanced approach integrates dissolution and absorption measurements. However, currently-used two-compartment absorptive apparatuses, employing a flat-sheet membrane are limited, in particular by the small membrane surface area that restricts the mass transfer, resulting in unrealistic experimental timeframes. This greatly impacts the suitability of such systems as a formulation development tool. The goal of this research is two-fold. First, to develop and test a high surface area, flow-through, absorptive dissolution testing apparatus, designed to provide in vivo relevant information about formulation performance in biologically relevant time frames. Second, to use this apparatus to obtain mechanistic insight into physical phenomenon occurring during formulation dissolution. Herein, the design and construction of a coupled dissolution-absorption apparatus using a hollow fiber membrane module to simulate the absorption process is described. The hollow fiber membrane offers a large membrane surface area, improving the mass transfer rates significantly. Following the development of a robust apparatus, its application as a formulation development tool was evaluated in subsequent studies. The dissolution-absorption studies were carried out for supersaturated solutions generated via anti-solvent addition, pH-shift and by dissolution of amorphous formulations. The research demonstrates the potential of the apparatus to capture subtle differences between formulations, providing insight into the role of physical processes such as supersaturation, crystallization kinetics and liquid-liquid phase separation on the absorption kinetics. The study also explores dissolution-absorption performance of amorphous solid dispersions (ASDs) and the influence of resultant solution phase behavior on the absorption profile. Residual crystalline content in ASDs is a great concern from a physical stability and dissolution performance perspective as it can promote secondary nucleation or seed crystal growth. Therefore, the risk of drug crystallization during dissolution of ASDs containing some residual crystals was assessed using absorptive dissolution measurements and compared to outcomes observed using closed-compartment dissolution testing. Mesoporous silica-based formulations are another type of amorphous formulations that are gaining increased interest due to higher physical stability and rapid release of the amorphous drug. However, their application may be limited by incomplete drug release resulting from the adsorption tendency of the drug onto the silica surface. Thus, the performance of mesoporous silica-based formulations was also evaluated in the absorptive dissolution testing apparatus to determine the impact of physiological conditions such as gastrointestinal pH and simultaneous membrane absorption on the adsorption kinetics during formulation dissolution. Overall, the aim of this research was to demonstrate the potential of the novel in vitro methodology and highlight the significance of a dynamic absorptive dissolution environment to enable better assessment of complex enabling formulations. In vivo, there are multiple physical processes occurring in the gastrointestinal lumen and the kinetics of these processes strongly depend on the absorption kinetics and vice-a-versa. Thus, using this novel tool, the interplay between solution phase behavior and the likely impacts on bioavailability of supersaturating drug delivery systems can be better elucidated. This approach and apparatus is anticipated to be of great utility to the pharmaceutical industry to make informed decisions with respect to formulation optimization.

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48

Peters, Mark George Dominic. "Developing a novel theory for the synthesis and design of membrane-based separations." Thesis, 2009. http://hdl.handle.net/10539/6862.

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A novel approach for the design and synthesis of membrane separation systems has been developed. The theory is shown to be applicable to both batch and continuous membrane operations, and has been formulated in such a way that it is valid for any type of membrane. In this thesis, however, only vapour permeation and pervaporation membranes are incorporated for illustration purposes. The method, which employs a graphical technique, allows one to calculate and visualise the change in composition of the retentate. An integral part of the approach was the derivation of the Membrane Residue Curve Map (M-RCM), and the related differential material balance which describes it. By definition, this plot shows the change, in time, of the retentate composition in a batch still. However, it has been shown that the M-RCM is applicable to conventional continuously-operated membrane units, as well as infinite reflux membrane columns. Finite reflux columns and cascades have been examined by using column sections (CS): any column, or arrangement, no matter how complex, can be broken down into smaller units, namely CS. The development of the Difference Point Equation (DPE) for non-constant flow allowed one to generate, and interpret, profiles for individual CS’s, which can ultimately be connected to form a membrane column arrangement. The profiles, which are more complex than those obtained in the M-RCM, exhibit a unique behavior. Since there is varying flow, the reflux is continually changing, orientating the profile so as to seek a stable node that is “mobile”. Thus, the movement of CS profile is dictated by the location and direction of the pinch point locus. Finally, having membrane permeators examined in an analogous manner to other separation methods, allows for easy synthesis and design of combinations of different processes. Hybrid distillation-membrane systems are analyzed by incorporating CS’s and the appropriate DPE’s which describe each. Investigating the arrangement as a thermally-coupled column introduces a novel way of synthesizing hybrids. Regions of feasibility, which are dictated by the relevant pinch point loci of each separation method, are ultimately sought.

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Alhazmi, Banan O. "Interfacially Polymerized Thin-Film Composite Membranes Based on Biophenolic Material for Liquid Separation." Thesis, 2020. http://hdl.handle.net/10754/664380.

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Abstract: The aim of this research is to fabricate thin-film composite (TFC) membranes using a synthetic derivative of plant-based phenols, as a non-toxic building block for interfacial polymerization. Classical interfacially polymerized composite membranes are heavily integrated in reverse osmosis and nanofiltration applications for water and wastewater treatment and most recently for chemical and pharmaceutical industries. Implementing sustainable practices in membrane fabrication by exploiting greener alternatives to conventional chemicals can directly reduce hazardous waste and ultimately lower the global energy and environmental burdens. In this study, allyl gallate was chosen as a monomer to form selective thin films by the interfacial reaction with trimesoyl chloride on top of an asymmetrically porous polyacrylonitrile support. The advantage of the unreacted allyl groups is that they can be in the future used as post-functionalization sites. The highly volatile organic phase solvents were additionally replaced by an isoparaffinic fluid, commercially known as Isopar G. The chemical composition and morphology of the membrane was evaluated using solid-state 13C NMR, FTIR, and SEM. The optimized membrane resulted in a permeance of 12±2 and 48±14 L m-2 h-1 bar-1 for respectively pure water and methanol with a rejection in the nanofiltration range.

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Hazazi, Khalid. "High-Performance Carbon Molecular Sieve Gas Separation Membranes Based on a Carbon-Rich Intrinsically Microporous Polyimide Precursor." Thesis, 2018. http://hdl.handle.net/10754/627771.

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The objective of this study was to investigate the transport properties and the microstructure of CMS membranes derived from a carbon-rich intrinsically microporous polyimide precursor. CMS membranes were prepared by a heat treatment of the polyimide precursor using a well-defined heating protocol in a horizontal tube furnace up to 1000 °C. A nitrogen purge was kept inside the furnace to remove all the evolved by-products as the precursor started to decompose and carbonize. The microstructures of the carbon molecular sieve membranes (CMSMs) were examined using wide-angle x-ray diffraction, Raman spectra, N2 adsorption and CO2 adsorption. The average interlayer spacing (d002) between the graphite plates was estimated using the data obtained by the WXRD. The average d002 decreased as a result of increasing the pyrolysis temperature; average d002 distances for CMS prepared at 700 and 1000 °C were estimated to be 0.40 to 0.38 nm, respectively. Raman spectra confirmed the progressive structural ordering as heat-treatment temperature increased. A substantial decrease in the intensity of the D band was observed as a function of pyrolysis temperature, indicating a decrease in the disordered structure. Graphitic structure and turbostratic carbon coexist in the as-prepared carbon membranes, of which the microcrystal size La and the stacking height Lc were increasing as a function of pyrolysis temperature. N2 adsorption showed a remarkable increase in the BET surface area as a function of pyrolysis temperature. BET surface areas for the pristine and CMSs prepared at 700 to 900 °C were in the range of 650 to 680 m2/g with a remarkable shift in the pore size distribution toward the ultra- microporous region. CO2 adsorption was used to estimate the surface area for pores with sizes of less than 1 nm. Surface areas were observed to increase from 350 m2/g at 500 °C to 857 m2/g at 800 °C, and then started dropping slightly from 857 to 650 m2/g at 800 to 1000 °C, respectively. This is believed to be caused by pore shrinkage effect being severe after 800 °C, which caused some pores to be hard to spot by the CO2 adsorption technique. The transport properties of the pristine and CMS membranes were tested using pure gases He, H2, N2, CH4, CO2, and O2. From the pristine to SBFDA-DMN-700°C, the selectivity increased significantly, with a massive loss in the permeability except for He and H2. From SBFDA-DMN- 700 °C to 900 °C, a substantial increase in selectivity with a moderate decline in permeability was observed. Beyond 900 °C, the permeability again decreased moderately, but a tremendous increase in the selectivity for N2/CH4, CO2/CH4, and H2/CH4 was observed.

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