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Showing 1 to 20 of 23 for “"Xerogels."”.
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The effect of the catalyst on the formation of RF xerogels
… of catalyst and sol pH. In this study organic xerogels were prepared using the pre described poly-condensation method, however, a wide range of base catalysts (Na₂CO₃, K₂CO₃, NaHCO₃, KHCO₃, NaOH, KOH, CaCO₃, SrCO₃, BaCO₃ and (NH₄)₂CO₃) were employed, at varying concentrations, with all other …
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Novel amorphous silica and silica xerogels for the adsorption of organic pollutants from water
… novel amorphous silica Quartzene and on silica xerogels, synthesised by a low cost and environmentally friendly synthesis, inspired from the work of Bangi, Rao A.P., Hirashima and Rao A.V. [1]. All adsorbents used in this study were also characterised by SEM, FTIR and BET analysis. The full …
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Development of novel formulations for mucosal delivery of protein based drugs
… lyophilised chitosan and thiolated chitosan xerogels have been developed for potential delivery of proteins via the buccal mucosa. Membrane dialysis to eliminate sodium acetate (NaAc) and annealing during lyophilisation cycle (developed by differential scanning calorimetry; DSC) were critical …
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Synthese und Charakterisierung von ferroelektrischen Xerogelen
… by special drying methods yielding so called xerogels or aerogels. In this research a focus was set on the synthesis of LiTaO3, LiNbO3 and KNbO3 using lithium-, tantalum,- niobium,- and potassiumethoxide as starting materials. The wet gels are dried at 40°C-50°. During the drying the gels …
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Development of nitrogen doped resorcinol-formaldehyde gels for carbon capture
Resorcinol-Formaldehyde (RF) xerogels are organic materials that have been widely studied due to their industrially relevant characteristics, such as high surface areas, suitable pore size and pore volume on which target species can be adsorbed; additionally, RF gels have significant potential to …
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Structure and performance of carbon xerogel molded emitters for micropropulsion applications
… tips. This study investigates the use of carbon xerogels for electrospray applications due to their exceptional properties such as large surface to volume ratio, robustness and pore uniformity. The substrates are created through a synthesis route which is advantageous for reproducibility. Single …
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Development and research of porous alumina xerogel membranes for electrospray propulsion applications
… section specifically focusses on cast alumina xerogels (porosities less than 90% typically around 40-50%) and briefly investigates a manufacturing procedure. The main problem facing the performance of these extractor membranes is the consistency of their geometry and porosity given the …
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ΜΕΛΕΤΗ ΕΠΙΦΑΝΕΙΑΚΩΝ ΙΔΙΟΤΗΤΩΝ ΚΑΙ ΚΑΤΑΛΥΤΙΚΗΣ ΔΡΑΣΤΙΚΟΤΗΤΑΣ ΠΑΡΑΣΚΕΥΑΣΜΑΤΩΝ ΥΔΡΟΞΕΙΔΙΩΝ ΤΟΥ ΑΡΓΙΛΙΟΥ
… OF WATER BY ORGANIC SOLVENTS LEADS TO XEROGELS WITH A HIGH SPECIFIC SURFACE AREA AND POROSITY, TENSION OF THE SOLVENT THAN THAT OF THE WATER. THE SURFACE PROPERTIES STUDIED WERE: MORPHOLOGICAL STRUCTURE, SPECIFIC SURFACE AREA, POROSITY,PORE SIZE DISTRIBUTION AND ADSORPTION CAPACITY. THE …
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BISMUTH-FUNCTIONALIZED SORBENTS FOR RADIOIODINE CAPTURE
… were performed to remove oil from silica xerogels. TEOS precursor gave isolated but larger pores while TEOS + MTMS precursor gels gave finer and interconnected pores. As a result of finer pore structure gels made with TEOS+MTMS have a higher surface area of 1068 ± 113 m2g-1. Bismuth …
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Carboxylate metallogels - an adventure in supramolecular chemistry
… gels were ca. 95-99% solvent. The creation of xerogels, by oven or freeze drying, allowed for better characterisation. The response of the gel to stimuli was explored and they were shown to interact with their environment. Dyes bromocresol green and methyl orange were both sorbed, in different …
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Intrinsic and Extrinsic Catalysis in Zirconium-based Metal-Organic Frameworks
… through synthesis modification. MOF powders and xerogels were prepared and characterized to highlight the desirable properties obtained through the gelation process. The materials were compared in the hydrolysis of DMNP and significant enhancement was observed for UiO-66 and NU-1000 xerogels. …
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Use of a quartz crystal microbalance to investigate the mechanical stability of silica xerogel membranes for volatile iodine capture
… integrity of the tested materials. Silica-based xerogels, prepared through sol-gel processing using only tetraethoxysilane (TEOS), TEOS with oil as porogen, TEOS with bismuth nanoparticles, and TEOS with both. The technique subjected the adsorbents to a gas stream and used adhesive-coated quartz …
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Characterisation and modification of hydrogel polymers
… of hydrogel polymers in their dehydrated state (xerogels) involves such techniques as elemental analysis, pyrolysis gas liquid chromatography, infra-red spectroscopy, density determination and surface characterisation by contact angle measurements. The characterisation of some commercially …
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NOVEL SYNTHETIC METHODS AND APPLICATIONS OF POROUS MATERIALS: AEROGEL FOAMS, METALLIC AEROGELS, AMORPHOUS AND GRAPHITIC CARBON AEROGELS
… powders. The process of making aerogels-via-xerogels allows to speed-up the solvent exchange process and bypasses supercritical fluid drying, resulting in time, energy, and materials efficient methodology. At their best, these carbon aerogels have high BET surface area (up to 1934 …
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Xerogel-Sequestered Transition Metal Catalysts for the Oxidation of Aqueous Halides with Hydrogen Peroxide: Toward a New Generation of Marine Antifouling Materials
… albeit only under acidic conditions. Active xerogels incorporating transition metals have been prepared to catalyze the oxidation of both bromide and chloride with H2O2 at the pH of seawater – the first evidence of chloride oxidation under oceanic conditions. Biological assays performed with …
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High temperature SO2 chemisorption on model systems. Implications for in-plume processes.
… were conducted on model Ca-aluminosilicate xerogels and on glasses with chemical compositions of common ash types. The materials were characterised using bulk and surface-sensitive techniques to gain insight into the mechanisms of scavenging and the reaction products formed. SO2 …
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Engineering ionic liquid ion sources for ion beam applications
… porous carbon based on resorcinol-formaldehyde xerogels is introduced as an emitter substrate. The target pore sizes and emitter geometries to attain the PIR are obtained through analytical estimates. The carbon xerogel can be shaped to the required micron-sized geometry through mechanical …
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Squaramide- and Urea-based Supramolecular Gels: Characterization and Environmental Applications
… The internal morphology of the corresponding xerogels was examined using transmission electron microscopy (TEM), while small-angle X-ray scattering (SAXS) was performed on wet gel samples to avoid drying artifacts. To further investigate the potential crystalline nature of the materials, …
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