A Method for the Cost-Effective Preparation of Organofunctional, Mesostructure Molecular Sieves for Toxic, Heavy Metal Ion Trapping and Heterogeneous Catalysis
The ability to create lower cost, industrial strength catalytic materials with desired pore sizes and with a chemically modified surface of organic groups can improve efficiency and selectivity in existing industrial processes that modify vast volumes of fluid. Template agents (usually organic molecules or ions) direct the crystallization of the zeolite including resulting pore size and shape.
Description of Technology
The innovation described in this invention relates to the development of sodium silicate hydrolysis chemistry in the presence of a surfactant that allows the silica to be incorporated into the framework of an organofunctional mesostructure. The use of sodium silicate hydrolysis is less expensive than using tetraethylorthosilicate (TEOS), which is an expensive alkoxide. The resulting structure is suitable for use as a heavy metal ion-trapping agent or as a heterogeneous catalyst.
- Lower cost: Use of sodium silicate as silica source is less expensive than TEOS.
- Enhanced catalysis and trapping: Tunable porosity to optimize catalysis of a given fluid's dynamics and composition. Can filter or trap metal ions in aqueous solutions.
- Enhanced selectivity: Over 20% of silica framework surface is functionalized with selected organic functional groups for directed catalysis.
- Greater stability: Framework is steam stable and organofunctional groups are more stable than similar surface modifications introduced by grafting techniques.
- Integrable: Uses conventional processing.
Catalytic applications benefit from large reaction surfaces and molecular channels. Industrial catalysis is becoming important in the conversion of large molecules and in petroleum refinement as oil quality is becoming more diverse.
Other applications include molecular sieve for separations by particle size and/or chemical properties, as an adsorbent, or as a trap for metals.
The invention is ready for a pilot production scale-up effort.
US 7166265 (issued Jan 23, 2007)
Thomas Pinnavaia, Jainisha Shah, Seong-Su Kim
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Michigan State University