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Showing 1 to 20 of 31 for “"ion-exchange capacity"”.
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Disposal of Bituminized and Other Low- and Medium-Level Wastes: Waste Characterization and the Retention of Migrating Radionuclides by Steel Corrosion Products
… radioactive waste disposal systems, the sorption characteristics of steel corrosion products were investigated with a special emphasis on competitive sorption between Sr and Na. The corrosion rate of steel exposed to various environments was studied qualitatively and, with some systems, …
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High Temperature Polymers for Proton Exchange Membrane Fuel Cells
Novel proton exchange membranes (PEMs) were investigated that show potential for operating at higher temperatures in both direct methanol (DMFC) and H2/air PEM fuel cells. The need for thermally stable polymers immediately suggests the possibility of heterocyclic polymers bearing appropriate ion …
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Polymer-supported reagents for disinfection of water
… was modified for use in small-scale chlorination of potable water. The resin was synthesized via sulfonyl chloride by modification of the strong acid cation exchange resin, Amberlyst-15. The products obtained after treatment contained -SO2NH2 and -SO 3H groups. The sulfonic acid groups were …
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The effect of metal ion exchange and alkali metal doping on the electrical conductivity of the Faujasite-type zeolite 13X
… was synthesized in the sodium form. Some transition metal cations were introduced into the zeolite framework by ion exchange reactions. These different cationic zeolite forms were doped or impregnated with sodium metal, utilizing the adsorptive properties of the zeolite. An A.C. technique was …
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Synthesis and Characterization of Hydrophilic-Hydrophobic Disulfonated Poly(Arylene Ether Sulfone)-Decafluoro Biphenyl Based Poly(Arylene Ether) Multiblock Copolymers for Proton Exchange Membranes (PEMs)
… block copolymers as proton exchange membranes (PEMs) has become an emerging area of research in recent years. Three series of hydrophilic/hydrophobic, fluorinated/sulfonated multiblock copolymers were synthesized and characterized in this thesis. These copolymers were …
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Layer-by-layer assembly of conducting membranes for photoelectrochemical cells
… transfer of silicon microwire arrays into an ion-conducting, ultrathin polymer membrane. The choice of LbL platform and the properties of the silicon surface control the film morphology, generating either a conformal coating around each wire or a bridging film across the top of the array. …
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Synthesis of anion exchange/activated carbon fiber hybrid materials for aqueous adsorption of toxic hexavalent chromium
… been identified as a carcinogen by ingestion. Unfortunately, it is present in drinking water supplies in United States. An effective, Point-of-Use (POU) based technology to remove Cr(VI) in tap water is urgently needed to protect human beings against this carcinogen. Due to the inadequate …
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Thermally stable ZSM-5 zeolite materials with new microporosities
… from the parent zeolite in an aqueous basic solution. This treatment has the effect to decrease the Si/Al ratio while keeping the zeolite structure almost unmodified. In all cases, we noticed an enhancement of the ion-exchange capacity. This property could be exploited industrially since the …
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Spray coated bentonite/MWCNT composite enzymatic biosensor for uric acid detection
… diagnostics, offering rapid and reliable detection of biological analytes. This study presents the development of an enzymatic uric acid (UA) biosensor based on a nanocomposite of bentonite (BT) and multi-walled carbon nanotubes (MWCNTs) fabricated via spray coating. The composite utilizes the …
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Synthesis and Characterization of Hydrophobic-Hydrophilic Multiblock Copolymers for Proton Exchange Membrane and Segmented Copolymer Precursors for Reverse Osmosis Applications
… materials used in the field of Proton Exchange Membrane Fuel Cells (PEMFCs) and Reverse Osmosis (RO) applications. In particular, wholly aromatic sulfonated poly(arylene ether sulfone)s are of considerable interest in the field of PEMFCs and RO, due to their affordability, high Tg, and …
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Proton Exchange Membrane Fuel Cell Systems Based on Aromatic Hydrocarbon and Partially Fluorinated Disulfonated Poly(Arylene Ether) Copolymers
This dissertation describes the past and recent progress in proton exchange membranes (PEM) for fuel cells. In particular the synthesis and characterization of materials for advanced alternative PEM were studied with an emphasis on structure-property and structure-property-performance …
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Synthesis and Characterization of Multiblock Copolymer Proton Exchange Membranes for High Temperature Fuel Cell Applications
The potential success of a proton exchange membrane (PEM) fuel cell as an alternative energy source depends highly upon the development of high performance PEMs. Typically, state-of-the-art PEMs have been perfluorinated sulfonated ionomer membranes such as Nafion® by DuPont. Although these …
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Solvothermal synthesis and characterisation of novel Gallium-sulphide compounds
… were synthesised under solvothermal conditions. Three-dimensional frameworks, which are analogous to previously reported structures, along with a large number of new hybrid supertetrahedral compounds were produced. Inorganic three-dimensional structures were obtained using dimethylamine as …
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The Influence of Aromatic Disulfonated Random and Block Copolymers' Molecular Weight, Composition,and Microstructure on the Properties of Proton Exchange Membranes for Fuel Cells
… spectroscopy. This allowed for utiliziation of the crude SDCDPS directly in the copolymerization to save money, energy, and time. Three series of tert-butylphenyl terminated disulfonated poly(arylene ether sulfone) copolymers (BPSH35, 6FSH35, and 6FSH48) with controlled molecular …
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Fundamental research of the solvent role in the ionothermal synthesis of microporous materials
… a group of porous materials with many applications in industry including but not limited to detergent builders and catalyst in the oil refining and petrochemical industry, due to their unique properties such as uniform pore size, large surface area and ion-exchange capacity. Researchers are …
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NON-PLATINUM GROUP METAL OXGYEN REDUCTION CATALYSTS AND THEIR MECHANISM IN BOTH ACID AND ALKALINE MEDIA: THE EFFECT OF THE CATALYST PRECURSOR AND THE IONOMER ON OXYGEN REDUCTION
… precursor structure to catalyst activity correlations are made. The donated samples have been divided into three classes based on their precursor; macrocyclic chelates, small molecule, and polymeric precursors. The precursor is one activity-dictating factor among many, but it is one of the most …
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Understanding of Ammonia Transport In Pem Fuel Cells
<p>This dissertation investigated ammonia (NH3) as a fuel contaminant to the anode in Proton Exchange Membrane Fuel Cells (PEMFCs). Since NH3 is fed to the anode in a gas phase and transferred to the cathode, the effect of a contaminant is distributed through MEA and quite complicated. This study …
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Surface chemistry design and characterization of anion exchange and activated carbon fibers for critical contaminants removal
… thesis is devoted to the design and characterization of surface chemistry of materials based on a novel fibrous platform for rapid and selective removal of trace contaminants. The first project is to study activated carbon fiber composites (ACFCs) for removal of NH3 from air. Three series of …
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Anion Exchange Membranes (AEMs), based on Polyamine Obtained by Modifying Polyketone, for Electrochemical Applications
Polymeric anion exchange materials can be key components for forming membranes for use in several electrochemical applications. Polyketones seem particularly promising as materials for making anion exchange membranes (AEMs), not only because the starting monomers, carbon monoxide and ethylene, are …
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Synthesis and characterization of aminated perfluoro polymer electrolytes
… electrolytes have been developed for use in anion exchange membrane fuel cells for years. However, due to the highly corrosive environment within these fuel cells, poor chemical stability of the polymers and low ion conductivity have led to high development costs and thus prevention from …
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