نتایج جستجو برای: gamma alumina
تعداد نتایج: 133827 فیلتر نتایج به سال:
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 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 fol...
Introduction Nanocrystalline gamma-phase (γ) alumina is among many polytypes of alumina that find extensive applications as a catalyst and catalytic supports. The most useful properties these aluminas provide as catalyst supports are high surface area and welldefined porosity. These properties result primarily from the nano-scale crystalline character of the alumina. The problem is that both th...
The influence of NaNO2, HNO3 and H2SO4 on the structure and morphology of gamma-alumina was investigated by XRD, BET, SEM and FT-IR spectroscopy. Selected amounts of NaNO2, HNO3 and H2SO4 were added to a solution of aluminum isopropoxide (as a precursor for the boehmite synthesis). The boehmite samples were calcined at 350 and 600 ℃ to form the semi-crystalline high surface area gamma-Al2O3. Th...
heavy metals, as gamma alumina nanoparticles pollutants, in water resources. Therefore, the purpose of this paper was to evaluate the removal of copper (II) ions from aqueous solutions using gamma alumina nanoparticles as a adsorbent. Batch adsorption studies carried out to study various parameters included contact time, initial concentration of copper (II) ions, pH, and gamma alumina nanoparti...
Mesoporous gamma-alumina granules, which are known as a common catalyst support in industrial applications were synthesized via the sol gel-oil drop method having a diameter of 1-2 mm. The effect of calcination temperature (450 and 750 °C) on the properties of gamma alumina granules were studied and the functionality of 20 wt% iridium catalyst on the alumina granules for hydrazine decomposition...
Abstract Introduction:Fluoride is one of the essential elements for human health and presence of its acceptable value prevents from tooth decay but excessive absorption of fluorine into the body cause many chronic problems such as flourosis. The aim of this study was to evaluate the effect of &alpha-Alumina and &gamma -Alumina on removal of fluoride from water. Methods: This experimental ...
supported vanadia catalyst was successfully synthesized using wet impregnation of gamma-alumina to study propane oxidative dehydrogenation (pod). the prepared catalysts were characterized with xrd, bet, and tpr tests. in a broad temperature range (340 to 630°c), effects of vanadia loading (2.7, 5.4, and 9 wt%) and propane to oxygen ratio (3/1 to 1/3) were investigated on propane conversion as w...
the mono-metallic and bi-metallic catalysts have been prepared by impregnating with solutions containing a compound of h2ptcl6,wo3 and 1ml hcl (0.1 mol). it should be noted that the catalysts’ activity and selectivity have been determined under these conditions : 450-5000c ,and 15-25atm by h2. for converting n-heptane , the molar ratio h2/c7h16 is 5 , and lhsv is 1.5ml/h. it has been proved tha...
bimetallic pt-v supported by gamma-alumina is used to observe the changes of nheptanewhen passed over this catalyst. the pt concentration was kept constant at0.1wt% while the concentration of the vanadium was 0.5wt%. the activity andselectivity of catalyst have been determined under conditions at 450-500 degreescentigrade and 15-30 attn. the experimental results show that the addition of second...
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