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Showing 1 to 20 of 25 for “"silicas"”.
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The development of nano-sized silicas as analytical tools
… m2 g-1. The properties of synthesized sub-micron silicas have been investigated using various techniques.<br/>One of the main aims of this work was to use the nanoscavengers for the analytical recovery of trace analytes from water. Nanoscavengers were prepared by chemically modifying mesoporous …
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Protein Thermal Stabilization and Delivery via Adsorption onto Porous Silicas
… that the adsorption of IpaD and Lf onto silicas is best fit by the Langmuir model. Silica pore size was determined to be a key factor in protein adsorption. If pores are less than 15 nm, adsorption is negligible. If the pores are between 15-25 nm, then monolayer coverage is achieved and …
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Development of Mesoporous Silicas, Responsive Polymer Microgels, and Related Nanocomposites
… describes the research work on the synthesis of silicas with spherical mesopores. Chapter 2 is focused on the synthesis of large-pore FDU-12 silicas at room temperature by using surfactants with large hydrophilic blocks and relatively small hydrophobic blocks (such as Pluronic F108 …
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Hydrogen Storage in Metal Fragments grafted Silicas and Chromium Hydrazide Gels
Hexagonally-packed mesoporous silicas (HMS) grafted with low-valent titanium, vanadium, and chromium organometallic fragments possessing oxidation states between (II) and (IV) were synthesized, tested for their hydrogen storage capacities, and characterized by XRD, nitrogen adsorption, XPS, and EA. …
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Direct liquid crystal templating of mesoporous silica
… with the development of ordered<br/>mesoporous silicas by direct templating from lyotropic liquid crystal phases of the<br/>surfactants Pluronic PI23, Pluronic F127, CTAB and Brij 78. The factors affecting the<br/>regularity, morphology, pore diameter and wall thickness of the templated …
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Flexible and Versatile Soft Templates for Mesoporous Silicas and Organosilicas Based on Pluronic Block Copolymer Surfactants and their Mixtures
… such as 2-D hexgonal ordered mesoporous silicas (SBA-15) as well as single-micelle-templated silica and organosilica nanotubes and nanospheres using triblock copolymer surfactants and their mixtures in the presence of a swelling agent. The introductory section, Chapter 1, will address the …
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Inorganic/organic hybrid polymers
… strands: the synthesis of organically modified silicas; the preparation of vinyl containing silsesquioxanes based on the hydrolysis of cyclohexyltrichlorosilane or propylmethacrylatepolysiloxane; the synthesis of latexes by co-polymerisation of either N-Isopropylacrylamide (NIPAM) or styrene …
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PEO-PPO-PEO Surfactant Mixtures as Templates for Silicas With Very Large Cylindrical Mesopores at Ambient Temperature and With Helical Mesopores at Sub-Ambient Temperature
… herein concerns the synthesis of mesoporous silicas through a surfactant-templating method. The approach taken involved the use of a mixed surfactant system of two poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) surfactants, with one of the copolymers containing a much larger …
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Understanding Functional Silica Additives for HDPE Composite Materials
… of the chemistry of Aerosil® grade pyrogenic silicas mainly A200, R8200, R9200, and R812S. Then, the work focused on the assessment of the processing characteristics, properties, and performance of the HDPE upon incorporation of the silicas. Thermogravimetric analysis (TGA), <sup>1</sup>H …
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Studies of tartaric acid modified nickel supported catalysts for enantioselective hydrogenation reactions
… the use of different types of ordered mesoporous silicas as supports of tartaric‐acid nickel in the aforementioned reaction. Even though the techniques of metal deposition explored did not allow incorporation of Ni in the internal surface of the materials, it was found that the morphology of the …
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Silica mesocellular foam and carbon nanofoam for fine chemical synthesis and separation
… and was extended to other non-ordered porous silicas. The S-MCF particles were engineered into a reverse- phase chromatographic column and achieved good separation ability for a mixture of aryl ketones. By relating chromatographic performance to S-MCF surface silanol chemistry, an improved …
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Hydrated silica on Mars: Global comparison and in-depth analysis at Antoniadi Crater
… This analysis reveals that Martian hydrated silicas exhibit a range of crystalline structures, from noncrystalline (opal-A or hydrated glass) to crystalline (quartz), implying a range in the maturity of these silica deposits. However, bulk SiO2 abundances show less diversity, with most …
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Thermodynamic and transport properties of self-assembled monolayers from molecular simulations
… properties of OMMs, in particular, porous silicas. A molecular study of structural and surface properties of a silica material with a 5 nm pore size, modified via chemical bonding of organosilanes with a range of sizes (C4, C8 and C18) is presented. Grand canonical MC simulations are …
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The role of colloidal phase in the measurement of pollutants in natural waters
… the laboratory. Artificial colloidal sols of the silicas in water were investigated to see how their filtration, employing a sequential filtration of a water sample through 1.6 (or 8 µm) and 0.1 µm cut-off filters, influenced a measurement of arsenic. The content of the filters after filtration …
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Functionalization of Metal Oxide Surfaces through Chemical Reactions and Physical Adsorption
… focused on metal oxides and functionalized silicas in acetone. Characterization of the adsorption was performed by solution UV/Vis, solid-state reflectance UV/Vis/NIR, and elemental analysis. Additional mechanistic studies focused on the role of Lewis acid/base interactions between the …
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Characterising Adsorption and Mass Transfer in Porous Media
… investigations on porous oxides; in particular silicas and aluminas commonly used as catalyst supports. The techniques used are demonstrated to be capable of acquiring information relevant to the performance of heterogeneous catalysts and adsorbents across the hierarchy of length scales relevant …
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Processi di desolforazione mediante l'utilizzo di adsorbenti e catalizzatori solidi
… compound is presented here. Pure SBA-15 and silicas, as well as Al-modified SBA-15 and MAS-5, were used as supports, due to the well known structural and textural stability of such mesoporous materials under the HDS reaction conditions. Transition metal oxides were added by wetness …
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