نتایج جستجو برای: Nanocrystalline Sodalite
تعداد نتایج: 10750 فیلتر نتایج به سال:
a facile effective stirring aging at room temperature prior to conventional hydrothermal treatment was employed in the template-free synthesis of micro- and nano-crystalline sodalites with two different initial gel compositions. the effect of initial si/al molar ratio, naoh concentration and stirring aging time were investigated on the morphology and particle size of the...
A facile effective stirring aging at room temperature prior to conventional hydrothermal treatment was employed in the template-free synthesis of micro- and nano-crystalline sodalites with two different initial gel compositions. The effect of initial Si/Al molar ratio, NaOH concentration and stirring aging time were investigated on the morphology and particle size of the...
Nanocrystalline NaNO3 enclathrated microporous material with intermediate structure (INT) between the well known zeolites sodalite (SOD) and cancrinite (CAN) can be prepared from aluminosilicate gels under addition of high amounts of NaOH and NaNO3 using low temperature conditions (333 K) within reaction periods of 1 96 h. The nanocrystalline products were characterized by X-ray powder diffract...
Temperature-dependent EPR data of potassium-electro-sodalite (PES), K8[Al6Si6O24](e-)2, are consistent with the occurrence of an antiferromagnetic phase transition at 71±2 K. PES is a Mott insulator which contains an unpaired electron in every sodalite cage. The same transition in sodium-electro-sodalite occurs at a considerably lower temperature (42 K), indicating that the exchange interaction...
A B S T R A C T: The K~mpf & Schwertmann (1982) procedure for concentrating iron oxides in soil clays by dissolution of kaolin and gibbsite by boiling for 1 h in 5 M NaOH may not dissolve all kaolin, and also results in the precipitation of sodalite. For the complete dissolution of kaolin in kaolin-rich soil clays a boiling time of 2 h in 5 M NaOH was required. The large amounts of sodalite pro...
The hydrothermal formation of sodium hydroxyborate enclathrated sodalite synthesized from an initial ternary mixture of mullite, cristobalite and corundum has been investigated. Depending on temperature and pressure the compound Na7-5[AlSi04]6[B(0H)4]1.5 • 2H20 could be synthesized in form of polycrystalline powder as well as in form of single crystals. The kinetics of the sodalite growth could...
Cancrinite, sodalite, and zeolite A have been found to form upon contacting hyperalkaline simulated tank waste (STW) with vadose zone sediments from the Hanford Reservation. Here, soluble silica and STW are used to study mineral formation and transformation. Two Hanford sediment fractions (diameters <50 and >50 lm instead of soluble silica) are also used as silica sources for comparison. A seri...
Optical properties of silver Ag(n) nanoclusters are demonstrated to be dependent on their size, structure and charge state. It is found that when being contained in the sodalite cavity of LTA zeolite the tetradecanuclear hexacation silver cluster Ag14(6+) is stable. Its lower-lying states and optical spectrum are theoretically determined using the quantum chemical TD-DFT method. Its ground stat...
in this study, a sodalite nanozeolite was synthesized and characterized by x-ray diffraction (xrd) and scanning electronic microscopy (sem). following the morphology evolution of the sodalite nanozeolite in the sem images illustrates the formation of the spherical particle with a size between 60 and 80 nm. then, carbon paste electrode (cpe) was modified by sodalite nanozeolite and ni2+ ions. th...
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