Mechanism of Zeolite A Nanocrystal Growth from Colloids at Room Temperature
Svetlana Mintova,
1,3
Norman H. Olson,
2
Valentin Valtchev,
3
Thomas Bein
1*
The formation and growth of crystal nuclei of zeolite A from clear
solutions at room temperature were studied with low-dose, high-resolution transmission electron microscopy in field emission mode
and with in situ dynamic light scattering. Single zeolite A crystals
nucleated in amorphous gel particles of 40 to 80 nanometers within 3 days at room temperature. The resulting nanoscale single crystals (10 to 30 nanometers) were embedded in the amorphous gel particles. The gel
particles were consumed during further crystal growth at room
temperature, forming a colloidal suspension of zeolite A nanocrystals
of 40 to 80 nanometers. On heating this suspension at 80°C,
solution-mediated transport resulted in additional substantial crystal
growth.
1 Department of Chemistry,
2 Department of Biology, Purdue University, West
Lafayette, IN 47907, USA.
3 Central Laboratory of
Mineralogy and Crystallography, Bulgarian Academy of Sciences, 92 Rakovski Street, 1000 Sofia, Bulgaria.
*
To whom correspondence should be addressed. E-mail:
tbein{at}chem.purdue.edu
