Method for the preparation of a synthetic faujasite material comprising monodisperse nanoparticles composed of single nanocrystals

Patent metadata

Field	Value
Publication number	US-10919028-B2
Application number	US-201315109059-A
Country	US
Kind code	B2
Filing date	Dec 30, 2013
Priority date	Dec 30, 2013
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

The present invention relates to a method for the preparation of faujasite nanocrystals, to faujasite nanocrystals, to a method for the preparation of a stable colloidal suspension of faujasite nanocrystals, to a stable colloidal suspension of faujasite nanocrystals, and to the use of said faujasite nanocrystals and said stable colloidal suspension of faujasite nanocrystals in various applications.

First claim

The invention claimed is:

1. A method for the preparation of a synthetic faujasite material having monodisperse nanoparticles composed of single nanocrystals, said nanoparticles having a size going from 5 to 400 nm and a silicon to aluminum molar ratio Si/Al going from 1 to 2.5, wherein said method comprises the following steps:
A) separately preparing a clear aqueous aluminate suspension A comprising at least one source of aluminum and at least one source of an alkali metal M1, and a clear aqueous silicate suspension B comprising at least one source of silicon and at least one source of an alkali metal M1, said separate preparations being prepared at 20-25° C.;
B) admixing the clear aqueous aluminate suspension A and the clear aqueous silicate suspension B until a resulting aqueous suspension is obtained, said resulting aqueous suspension being free of organic-templating agents and having the following molar composition:
x 1 M 1 2 O:yAl 2 O 3 :10 SiO 2 :zH 2 O   (I)

in which:
0.1≤y≤5,
20≤z≤400, and preferably 20≤z≤320,
5≤x 1 ≤13;
wherein in step B), the clear aqueous silicate suspension B only is cooled to a temperature of 0° to 5° C., then the clear aqueous aluminate suspension A is added drop wise to the cooled clear aqueous silicate suspension B, while said clear aqueous silicate suspension B is kept at a temperature going from 0° to 5° C. for the duration of the dropwise addition,
C) aging the resulting suspension of step 2) at a temperature going from about 20° C. to about 30° C. to form nuclei;
D) heating the resulting suspension of step 3) at a temperature going from about 40° C. to about 150° C., for a period of time sufficient to produce the desired synthetic faujasite material comprising monodisperse nanoparticles composed of single nanocrystals; and
E) recovering said synthetic faujasite material comprising monodisperse nanoparticles composed of single nanocrystals.

2. The method according to claim 1 , wherein the source of aluminum is aluminum powder.

3. The method according to claim 1 , wherein the source of silicon is colloidal silica.

4. The method according to claim 1 , wherein the source of alkali metal M1 is selected from a source of Na, a source of K and a source of Li.

5. The method according to claim 1 , wherein in step B), the clear aqueous aluminate suspension A and the clear aqueous silicate suspension B are mixed under vigorous mechanical stirring or sonication.

6. The method according to claim 1 , wherein the temperature of step C) is maintained for at least 12 hours.

7. The method according to claim 1 , wherein step E) is performed by filtration, centrifugation or dialysis.

8. The method according to claim 1 , wherein it further comprises the following step:
F) drying the single nanocrystals of synthetic faujasite material obtained in step E).

9. A method for the preparation of a stable colloidal suspension of a synthetic faujasite material having monodisperse nanoparticles composed of single nanocrystals, said method comprising the following steps:
A) preparing a synthetic faujasite material comprising monodisperse nanoparticles composed of single nanocrystals according to the method as defined in claim 1 ; and
B) dispersing in a solvent the synthetic faujasite material comprising monodisperse nanoparticles composed of single nanocrystals of step A).

10. The method according to claim 9 , wherein the solvent is selected from water, acetone and alcohols.

Assignees

• Centre Nat Rech Scient

Inventors

• MINTOVA Svetlana
• Awala Hussein
• Gilson Jean-Pierre
• VALTCHEV Valentin

Classifications

• B01J35/45

  Nanoparticles · CPC title

• B01J35/23

  in a colloidal state · CPC title

• C01B39/20 Primary

  Faujasite type, e.g. type X or Y · CPC title

• C01P2004/62

  Submicrometer sized, i.e. from 0.1-1 micrometer · CPC title

• C01P2004/64

  Nanometer sized, i.e. from 1-100 nanometer · CPC title