The synthesis and sodium-silver ion exchange of sodalites

Aluminosilicate sodalites of three different types--chlorosodalite, basic sodalite, and oxalate sodalite--have been synthesized in their sodium forms using hydrothermal synthesis. The syntheses were investigated in terms of their relative rates of crystallization and final crystallinities using powder X-ray diffraction. These sodalites were subsequently loaded with silver by aqueous ion exchange. The exchange was studied primarily by monitoring the solution phase. Rate of exchange and equilibrium behavior have been established over the temperature range of 25-80°C for all three types. Extreme selectivity toward silver over sodium was observed, with little dependence on temperature. Both sodium and silver sodalites were characterized by powder diffraction, and crystallographic data for silver sodalites have been derived using Rietveld refinement. Electron micrographs of sodalites have been used for investigations of crystallite morphology and size. Silver sodalites have been observed to manifest various optical properties including photochromic, barochromic, thermochromic, and fluorescent behavior.

Keywords:

• Chlorosodalite
• Basic Sodalite
• Oxalate Sodalite
• Synthesis
• Silver Ion Exchange