Modeling spontaneous formation of precursor nanoparticles in clear-solution zeolite synthesis

• Type: Article in International Scientific Journal
• Date: 2005

Authors

M. Jorge (Author) FEUP; Scott M. Auerbach (Author) Other; P. A. Monson (Author) Other

Journal

Title: Journal of the American Chemical Society

Vol. 127 No. 41

Pages: 14388-14400

ISSN: 0002-7863

Publisher: American Chemical Society

Indexing

ISI Web of Science

Scopus

COMPENDEX

Scientific classification

FOS: Engineering and technology > Chemical engineering

CORDIS: Physical sciences > Chemistry > Molecular chemistry

Other information

Abstract (EN): We present a lattice model describing the formation of silica nanoparticles in the early stages of the clear-solution templated synthesis of silicalite-1 zeolite. Silica condensation/hydrolysis is modeled by a nearest-neighbor attraction, while the electrostatics are represented by an orientation-dependent, short-range interaction. Using this simplified model, we show excellent qualitative agreement with published experimental observations. The nanoparticles are identified as a metastable state, stabilized by electrostatic interactions between the negatively charged silica surface and a layer of organic cations. Nanoparticle size is controlled mainly by the solution pH, through nanoparticle surface charge. The size and concentration of the charge-balancing cation are found to have a negligible effect on nanoparticle size. Increasing the temperature allows for further particle growth by Ostwald ripening. We suggest that this mechanism may play a role in the growth of zeolite crystals.

Language: English

Type (Professor's evaluation): Scientific