830. The thermal dehydration of silica xerogel promoted by alkaline-earth chlorides

1962 ◽  
pp. 4265 ◽  
Author(s):  
N. Henry ◽  
R. A. Ross
Keyword(s):  
Alkaline Earth ◽  
Thermal Dehydration ◽  
Silica Xerogel ◽  
Alkaline Earth Chlorides

Diffusion of alkali and alkaline earth chlorides through a parchment-supported silver iodide membrane

1972 ◽  
Vol 25 (9) ◽  
pp. 1837 ◽  
Author(s):  
Beg M Aijaz ◽  
S Pratap
Keyword(s):  
Silver Iodide ◽  
Alkaline Earth ◽  
Diffusion Rate ◽  
Activation Parameters ◽  
Weak Field ◽  
Thermodynamic Quantities ◽  
Constant Flow ◽  
Ion Hydration ◽  
Diffusion Rates ◽  
Alkaline Earth Chlorides

Diffusion rates of KCl, NaCl, LiCl, BaCl2, CaCl2, and MgCl2 through a parchment-supported silver iodide membrane have been measured at various temperatures using a constant flow method. Activation energies and various Eyring activation parameters for the diffusion of these electrolytes have also been evaluated. The diffusion rate sequences obtained are KCl > NaCl > LiCl and BaCl2 > CaCl2 > MgCl2 and they point towards the weak field strength of the membrane fixed charged groups. Diffusion coefficients and the various Eyring activation parameters have been related to the ionic hydrated sizes and the various thermodynamic quantities of ionic hydration thus emphasizing the importance of ion hydration in diffusion across the membrane.

Structure of Zirconia Nanoparticles used for Pillaring of Clay

2001 ◽  
Vol 703 ◽  
Author(s):  
V. A. Sadykov ◽  
T. G. Kuznetsova ◽  
V. P. Doronin ◽  
T. P. Sorokina ◽  
D. I. Kochubei ◽  
...  
Keyword(s):  
Alkaline Earth ◽  
Nitrogen Adsorption ◽  
Structural Features ◽  
Concentration Addition ◽  
X Ray ◽  
Oxygen Anions ◽  
Nitrogen Adsorption Isotherms ◽  
Alkaline Earth Chlorides ◽  
Zirconium Concentration ◽  
Zirconia Nanoparticles

ABSTRACTSAXS and EXAFS were applied to study genesis of polynuclear zirconium hydroxyspecies in pillaring solutions as dependent upon the zirconium concentration, addition of alkaline-earth chlorides and aging. After the montmorillonite clay pillaring, the structure of zirconium nanopillars was characterized by applying X-ray structural analysis, UV-Vis, FTIRS of adsorbed CO and nitrogen adsorption isotherms. Main pillaring species appear to be nanorods comprised of several Zr4 tetramers. Basic structural features of the tetramers are preserved in zirconia nanoparticles fixed between alumosilicate layers in pillared clays. In calcined samples, those nanoparticles contain only bridging hydroxyls and/or oxygen anions responsible for bonding within pillars and between pillars and clay sheets.

Sign in / Sign up

Export Citation Format

Share Document