2 research outputs found
Solvent-Free Synthesis of Zeolites from Solid Raw Materials
As important industrial materials, microporous zeolites
are necessarily
synthesized in the presence of solvents such as in hydrothermal, solvothermal,
and ionothermal routes. We demonstrate here a simple and generalized
solvent-free route for synthesizing various types of zeolites by mixing,
grinding, and heating solid raw materials. Compared with conventional
hydrothermal route, the avoidance of solvents in the synthesis not
only significantly reduces the waste production, but also greatly
increases the yield of zeolite products. In addition, the use of starting
solid raw materials remarkably enhances the synthesis efficiency and
reduces the use of raw materials, energy, and costs
Highly Mesoporous Single-Crystalline Zeolite Beta Synthesized Using a Nonsurfactant Cationic Polymer as a Dual-Function Template
Mesoporous
zeolites are useful solid catalysts for conversion
of bulky molecules because they offer fast mass transfer along with
size and shape selectivity. We report here the successful synthesis
of mesoporous aluminosilicate zeolite Beta from a commercial cationic
polymer that acts as a dual-function template to generate zeolitic
micropores and mesopores simultaneously. This is the first demonstration
of a single nonsurfactant polymer acting as such a template. Using
high-resolution electron microscopy and tomography, we discovered
that the resulting material (Beta-MS) has abundant and highly interconnected
mesopores. More importantly, we demonstrated using a three-dimensional
electron diffraction technique that each Beta-MS particle is a single
crystal, whereas most previously reported mesoporous zeolites are
comprised of nanosized zeolitic grains with random orientations. The
use of nonsurfactant templates is essential to gaining single-crystalline
mesoporous zeolites. The single-crystalline nature endows Beta-MS
with better hydrothermal stability compared with surfactant-derived
mesoporous zeolite Beta. Beta-MS also exhibited remarkably higher
catalytic activity than did conventional zeolite Beta in acid-catalyzed
reactions involving large molecules