نتایج جستجو برای: Nanocrystalline Sodalite

تعداد نتایج: 10750  

Journal: :chemistry of solid materials 2015
s. m. pourali a. samadi-maybodi

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. Samadi-Maybodi, S. M. Pourali

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...

Journal: :Acta Crystallographica Section A Foundations of Crystallography 2010

2011
J.-Ch. Buhl S. Cramm

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...

2000
VOJISLAV I. SRDANOV

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...

1991
Balwant Singh R J Gilkes

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...

2013
W. Hoffmann

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...

2005
Kholoud Mashal James B. Harsh Markus Flury Andrew R. Felmy

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...

Journal: :Physical chemistry chemical physics : PCCP 2013
Ngo Tuan Cuong Hue Minh Thi Nguyen Minh Tho Nguyen

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...

Journal: :iranian journal of hydrogen & fuel cell 2015
seyed karim hassaninejad-darzi fereshte yousefi

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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