نتایج جستجو برای: hydrothermal crystallization
تعداد نتایج: 39763 فیلتر نتایج به سال:
In this investigation we synthesized NaX-Nanozeolite by hydrothermal crystallization conditions.These nanoparticles were prepared at different conditions in a temperature controlled shaker. Thesynthesized zeolites were characterized by instrumental analysis methods, such as X-raydiffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) andtransmission electron microscopy (...
Perlite or pearl stone is a natural glass which has formed by rapid cooling of viscous lava or magma. Perlite is mainly composed of silica, aluminum, potassium and sodium. In this experiment, perlite was used as a low-cost source of Si and Al to synthesis of sodalite zeolite using the alkaline hydrothermal treatment. A statistical Taguchi design of experiments was employed to evaluate the effec...
The crystallizatio n of mic roporous material SAPO-37 was studied under hydrothermal synthesis (HTS) and dry gel conversion (DGC) conditions. The evolution of the intermediate phases as a function of crystallization time was followed by several techniques including PXRD , SEM, AFM, and solid-state NMR. For DGC, SAPO-37 crystallizes from a semi-crysta lline layered precursor containing large por...
Abstract: Nano pore Mordenite membranes were prepared on the outer surface of ceramic tubular tubes via hydrothermal synthesis and evaluated for dehydration pervaporation of water unsymmetrical dimethylhydrazine UDMH mixtures. Highly water-selective mordenite membranes were prepared and the optimum reaction condition was found to be 24 h crystallization time and 170 °C crystallization temperatu...
An alumino-silicate zeolite, Linde Type-A (LTA) has been prepared from aluminium powder and sodium metasilicate by hydrothermal process. The zeolite was characterized by FTIR and X-ray diffraction (XRD) analysis and by measuring the surface acidity using KOH as adsorbate. The surface acidity of LTA zeolite varied greatly with varying synthesized conditions such as crystallization temperature, c...
vanadium silicates such as v-al-analcime, v-analcime, v-magediite and v-zsm-11 were synthesized using vanadium pentoxide or vanadyl sulfates. vanadium silicates with analcime structure with and without aluminum (v-al-analcime, v-analcime) were prepared as pure phase by hydrothermal crystallization from a gel with molar composition of (1 sio2; 0.2 v2o5; 1 na2o; 0.034 al2o3; 35.7 h2o) and (1 sio2...
The previously unobserved chair conformation of C-methylcalix[4]resorcinarene has been found in three different supramolecular solids, prepared by hydrothermal synthesis. The existence of the chair, crown and flattened cone conformations of C-methylcalix[4]resorcinarene demonstrates the dependence of the molecular conformation upon the templating molecules, and upon the specifics of the crystal...
The Thermal Emission Spectrometer (TES) on the Mars Global Surveyor spacecraft has detected deposits of coarse-grained, gray crystalline hematite in Sinus Meridiani, Aram Chaos, and Vallis Marineris. We argue that the key to the origin of gray hematite is that it requires crystallization at temperatures in excess of about 100 ◦C. We discuss thermal crystallization (1) as diagenesis at a depth o...
[1] Abstract: Analysis of crystal size distributions (CSD) of plagioclase in gabbros from the Oman ophiolite indicates that cooling rates in the lower crust beneath a mediumto fast-spreading oceanic ridge did not vary smoothly with depth. Cooling rates in the upper half of the gabbro section were approximately 1.5–2 times faster than in the lower half of the gabbro section during igneous crysta...
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