One-step method for the synthesis of high silica content zeolites in organic-free media

Patent metadata

Field	Value
Publication number	US-10407312-B2
Application number	US-201515511776-A
Country	US
Kind code	B2
Filing date	Sep 17, 2015
Priority date	Sep 17, 2014
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

In an embodiment, the present disclosure pertains to a composition comprising a zeolite with high silica content. In some embodiments, the silica to aluminum ratio (SAR) for the zeolite is 2:1. In some embodiments, the zeolite comprises Zeolite HOU-2 (LTA-type). In some embodiments, the silica to aluminum ratio (SAR) for the zeolite is >3. In some embodiments, the zeolite comprises Zeolite HOU-3 (FAU type). In some embodiments, the zeolite is synthesized using a one-step method. In some embodiments, the zeolite is synthesized without the use of an organic structure-directing agent (OSDA). In some embodiments, the zeolite is synthesized without the use of post-synthesis dealumination. In some embodiments, the zeolite is synthesized without the use crystal seeds. In some embodiments, the zeolite is used in commercial ion exchange. In some embodiments, the zeolite is used for catalysis reaction. In some embodiments, the zeolite is highly thermostable.

First claim

What is claimed is:

1. A one-step organic-free method for the synthesis of LTA-type zeolites comprising:
preparing a zeolite growth solution comprising an alumina source and a hydroxide source;
adding a silica source to the zeolite growth solution to form an initial gel mixture;
crystallization of the initial gel mixture;
collecting products formed; and
isolating the zeolites formed from the crystalline products, wherein the synthesis of the zeolites is without the use of organic structure-directing agents, wherein the synthesis of the zeolite is without the use of crystal seeds, wherein the silicon-to-hydroxide ratio in the initial gel mixture is greater than about 1 and less than about 1.5, and wherein the synthesized zeolite has a silicon-to-aluminum ratio of at least 2:1.

2. The method of claim 1 further comprising adding a cation as an extra-framework counterion in the zeolite growth solution.

3. The method of claim 2 , wherein the extra-framework cation is an alkali metal.

4. The method of claim 2 , wherein the extra-framework cation is Na + .

5. The method of claim 1 , wherein the alumina source is selected from a the group consisting of aluminum sulfate, aluminum isopropoxide, aluminum metal, alumina, natural Al 2 O 3 containing clays and minerals, sodium aluminate, and zeolites using crystal phase transformation to LTA.

6. The method of claim 1 , wherein the alumina source is sodium aluminate.

7. The method of claim 1 , wherein the hydroxide source is sodium hydroxide.

8. The method of claim 1 , wherein the silica source is selected from the group consisting of fumed silica, sodium silicate, tetraethylorthosilicate (TEOS), colloidal silica, natural silicon dioxide-containing clays and minerals, or zeolites.

9. The method of claim 1 , wherein the silica source is colloidal silica.

10. The method of claim 9 , wherein the colloidal silica has a size ranging from about 8 nm to about 25 nm.

11. The method of claim 1 , wherein the step of crystallization of the initial gel mixture comprises heating the initial gel mixture at temperatures ranging from about 25° C. to about 290° C. for at least 1 day.

12. The method of claim 1 , wherein the zeolites are synthesized without the use of post-synthesis dealumination.

13. The method of claim 1 , wherein the zeolites have a cubic morphology.

14. The method of claim 1 , wherein the zeolites have a spheroidal morphology.

15. The method of claim 1 , wherein the size of the zeolites ranges from about 1 nm to about 5 μm.

16. A one-step organic-free method for the synthesis of FAU-type zeolites comprising:
preparing a zeolite growth solution comprising an alumina source and a hydroxide source;
adding a silica source to the zeolite growth solution to form an initial gel mixture;
heating the initial gel mixture from about 25° C. to about 140° C.;
collecting products formed; and
isolating the zeolites formed from the crystalline products, wherein the synthesis of the zeolites is without the use of organic structure-directing agents, wherein the synthesis of the zeolite is without the use of crystal seeds, wherein the silicon to hydroxide ratio in the initial gel mixture is at least 1.5, and wherein the synthesized zeolite has a silicon-to-aluminum ratio of at least 3:1.

17. The method of claim 16 further comprising adding a cation as an extra-framework counterion in the zeolite growth solution.

18. The method of claim 17 , wherein the extra-framework cation is an alkali metal.

19. The method of claim 18 , wherein the extra-framework cation is Na + .

20. The method of claim 16 , wherein the method further comprises incorporation of a rare earth metal in the synthesized zeolite.

21. The method of claim 16 , wherein the alumina source is selected from a the group consisting of aluminum sulfate, aluminum isopropoxide, aluminum metal, alumina, natural Al 2 O 3 containing clays and minerals, sodium aluminate, and zeolites using crystal phase transformation to LTA.

22. The method of claim 16 , wherein the alumina source is sodium aluminate.

23. The method of claim 16 , wherein the hydroxide source is sodium hydroxide.

24. The method of claim 16 , wherein the silica source is selected from the group consisting of fumed silica, sodium silicate, tetraethylorthosilicate (TEOS), colloidal silica, natural silicon dioxide-containing clays and minerals, or zeolites.

25. The method of claim 16 , wherein the silica source is colloidal silica.

26. The method of claim 25 , wherein the colloidal silica has a size ranging from about 8 nm to about 25 nm.

27. The method of claim 16 , wherein the silica is fumed silica.

28. The method of claim 16 , wherein the step of crystallization of the initial gel mixture comprises heating the initial gel mixture initial gel mixture at a temperature of at least 100° C. for at least 1 day.

Assignees

• Univ Houston System

Inventors

• Conato Marlon T
• Oleksiak Matthew D
• Rimer Jeffrey D

Classifications

• C01P2004/38

  cube-like · CPC title

• C01B39/46 Primary

  Other types characterised by their X-ray diffraction pattern and their defined composition {(C01B39/023, C01B39/026, C01B39/06 take precedence)} · CPC title

• C01P2004/61

  Micrometer sized, i.e. from 1-100 micrometer · CPC title

• B01J39/14

  Base exchange silicates, e.g. zeolites · CPC title

• B01J37/0072

  Preparation of particles, e.g. dispersion of droplets in an oil bath · CPC title