نتایج جستجو برای: surfactant coated alumina
تعداد نتایج: 78500 فیلتر نتایج به سال:
This contribution presents the production of polymer-coated iron oxide magnetic nanoparticles carrying functional groups on their surface and their basic characterization. The preparation of polymer-coated nanoparticles was carried out by a two-step process. In the first step, magnetite (Fe3O4) nanoparticles were prepared by a co-precipitation method from the solutions of FeCl2.4H2O and FeCl3.6...
The esterification activity of microbial lipase (triacyl glycerol hydrolase, E.C. 3.1.1.3) in water-organic biphasic solvent system has been investigated. The lipase produced from Rhizopus arrhizus NCM997 strain by solid-state fermentation, using rice bran as substrate, exhibited novel capability of catalyzing esterification reaction. The partially purified lipase was coated with nonionic surfa...
1. Introduction Mesoporous materials with ordered arrays of uniform nanochannels of a controllable size have wide-ranging applications, one of which is membrane separation. In order to be used as a membrane for size-exclusive separation of molecules, it is necessary to synthesize a defect-free structure with continuous nanoporosity. Mesoporous silica and porous anodic alumina have been extensiv...
in this study, preparation of nano-sized gamma alumina with high specific surface area and high yield by thereaction between aluminum nitrate and sodium carbonate, without using any surfactant is reported. bohemite (aluminum oxyhydroxide) was prepared as a precursor by strict control of ph and reaction temperature. the gel produced was purified by washing followed by centrifugation. the specifi...
In this paper, the effect of the material and distance of the substrate on the characteristics of gamma alumina nanopowder coated by plasma spray method are investigated. For this purpose alumina nanopowder were coated on the two types of stainless steel and Pyrex glass substrates using a plasma torch. Morphological characteristics of the prepared nanolayer are studied by investigating the scan...
Mesoporous templated MCM-48 silica was prepared using a C16 surfactant as template. The MCM-48 powders and thin films were characterized by different techniques. Two types of porous supports were used, namely macroporous α-alumina and silicon microsieves. The supported MCM-48 layers were applied as liquid permeable membranes in pressure-driven nanofiltration and electric field-mediated ion tran...
Monolithic ceramics have been fabricated from coated green fibers to create fibrous microstructures. The fibrous monoliths consist of high aspect ratio polycrystalline regions (cells) of a primary phase separated by thin secondphase regions (cell boundaries) designed to improve fracture resistance. The cells are the remnants of the green fiber which consists of ceramic powder and a polymer bind...
The reaction of formaldehyde with β-diketones (Hantzsch reaction) has been often employed for derivatizing formaldehyde to the fluorescent compounds.1,2 Among βdiketones, 5,5-dimethyl-1,3-cyclohexanedione (dimedone, Fig. 1) seems to be the most promising because of the strong fluorescence intensity and stability of the formed compound. Recently, we developed a method for concentrating trace hyd...
The desorption behavior of cationic-nonionic surfactant mixtures, tetradecyltrimethylammonium chloride (TTAC) and pentadecylethoxylated nonyl phenol (NP-15), at the alumina-water interface was studied. It has been found that while nonionic NP-15 itself does not adsorb at alumina-water interface, it will do so with cationic TTAC preadsorbed at the interface. During the desorption process, howeve...
A novel process of fabricating various oxide nanostructures on glass substrates is described. Transparent porous alumina films ( 6–150 nm) were first formed in acid solutions by anodization of aluminum layers sputter-deposited on a glass plate coated with a tin-doped indium oxide film. The porous alumina structures after pore-widened were then used as a host or a template in a sol–gel process t...
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