Aerogel sorbents

• US 9,931,612 B2
• Filed: 11/25/2015
• Issued: 04/03/2018
• Est. Priority Date: 04/28/2012
• Status: Active Grant

• Current Assignee: Aspen Aerogels, Incorporated
• Original Assignee: Aspen Aerogels, Incorporated
• Inventors: Begag, Redouane, Rhine, Wendell E, Dong, Wenting
• Primary Examiner(s): Soliman, Haytham
• Application Number:
  US14/951,795
• Publication Number:
  US 20160074831A1
• Time in Patent Office: 860 Days
• Field of Search: 423228, 556424, 556413
• CPC Class Codes: B01D 2253/20 Organic adsorbents
• CPC Class Codes: B01D 2253/25 Coated, impregnated or composite adsorbents
• CPC Class Codes: B01D 2257/504 Carbon dioxide
• CPC Class Codes: B01D 53/02 by adsorption, e.g. preparative gas chromatography solid sorbent compositions B01J20/00, preparation of inorganic compounds or elements C01
• CPC Class Codes: B01D 53/62 Carbon oxides
• CPC Class Codes: B01J 20/103 comprising silica
• CPC Class Codes: B01J 20/22 comprising organic material
• CPC Class Codes: B01J 20/28011 Other properties, e.g. density, crush strength
• CPC Class Codes: B01J 20/28047 Gels
• CPC Class Codes: B01J 20/28059 being less than 100 m2/g
• CPC Class Codes: B01J 20/28061 being in the range 100-500 m2/g
• CPC Class Codes: B01J 20/28071 being less than 0.5 ml/g
• CPC Class Codes: B01J 20/28073 being in the range 0.5-1.0 ml/g
• CPC Class Codes: B01J 20/28076 being more than 1.0 ml/g
• CPC Class Codes: B01J 20/28083 being in the range 2-50 nm, i.e. mesopores
• CPC Class Codes: B01J 20/3085 Chemical treatments not covered by groups B01J20/3007 - B01J20/3078
• CPC Class Codes: B01J 20/3248 the functional group or the linking, spacer or anchoring group as a whole comprising at least one type of heteroatom selected from a nitrogen, oxygen or sulfur, these atoms not being part of the carrier as such
• CPC Class Codes: B01J 20/3272 Polymers obtained by reactions otherwise than involving only carbon to carbon unsaturated bonds
• CPC Class Codes: Y02A 50/20 Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
• CPC Class Codes: Y02C 20/40 of CO2

Abstract

The current invention describes methods and compositions of various sorbents based on aerogels of various silanes and their use as sorbent for carbon dioxide. Methods further provide for optimizing the compositions to increase the stability of the sorbents for prolonged use as carbon dioxide capture matrices.

Claims

1. An amine-functionalized hydrophobic silica aerogel comprising a silica network, at least one hydrophobic element covalently bound to the silica network, and at least one alkylamino group covalently bound to the silica network;

wherein the hydrophobic element is a monoalkylsilane or a dialkylsilane.

2. The aerogel of claim 1, wherein the hydrophobic element is a monoalkylsilane.

3. The aerogel of claim 2, wherein the alkylamino group is a mono, di, tri, or poly amine-containing group.

4. The aerogel of claim 2, wherein the alkylamino group is selected from the group consisting of:

3-aminopropyl;

N-(2-aminoethyl)-3-aminopropyl;

propyldiethylene triamino;

aminophenyl;

N-3-([amino(polypropylenoxy])-amino-propyl; and

polyethyleneimino.

5. The aerogel of claim 2 wherein the monoalkylsilane comprises methylsilane, ethylsilane, propylsilane, or phenylsilane.

6. A carbon dioxide capture sorbent comprising the amine-functionalized hydrophobic silica aerogel of claim 2, wherein the aerogel comprises at least an open pore accessible to carbon dioxide.

7. The sorbent of claim 6, wherein the density of the aerogel is between 0.01 and 0.6 g/cc.

8. The sorbent of claim 6, wherein alkylamino groups comprise 5 wt % to 70 wt % of the amine-functionalized hydrophobic silica aerogel.

9. The sorbent of claim 6, wherein the carbon dioxide capture rate of the amine-functionalized hydrophobic silica aerogel is between 0.08 gram and 0.5 gram of carbon dioxide per gram of the aerogel in the sorbent.

10. The sorbent of claim 6, wherein the sorbent has no more than a 20% degradation in capture rate after exposing the sorbent to temperatures up to 130°

C. through up to 500 capture-regeneration cycles.

11. The sorbent of claim 6, wherein the hydrophobic silica aerogel has a moisture content of less than 10 wt %.

12. The amine-functionalized hydrophobic silica aerogel of claim 1, produced by the following process:

hydrolyzing at least a monoalkylalkoxysilane or a dialkylalkoxysilane, reacting the hydrolyzed monoalkylalkoxysilane or dialkylalkoxysilane with at least a hydrolyzed aminosilane to form a gel, and drying the resulting gel to obtain an aerogel.

13. The aerogel of claim 12, wherein the alkylalkoxysilane is selected from the group consisting of methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldiethoxysilane, diethyldimethoxysilane, and a combination thereof.

14. The aerogel of claim 12, wherein the aminosilane comprises mono, di, tri or poly amine groups.

15. The aerogel of claim 12, wherein the aminosilane is selected from the group consisting of 3-aminopropylmethyldiethoxysilane, 3-aminopropyl-triethoxysilane (APTES), 3-aminopropyl-trimethoxysilane (APTMS), N-(2-aminoethyl)-3-aminopropyltriethoxysilane (AE-APTES), N-(2-aminoethyl)-3-aminopropyl-trimethoxysilane (AE-APTMS), p-aminophenyltrimethoxysilane, N-3-([amino(poly-propyleneoxy])-amino-propyl-trimethoxy-silane (aminoether), (3-trimethoxylsilylpropyl)-diethylenetriamine (TMS-DETA), trimethoxy-silane modified polyethyleneimine and a combination thereof.

16. The amine-functionalized hydrophobic silica aerogel of claim 1, produced by the following process:

hydrolyzing and condensing at least a monoalkylalkoxysilane or a dialkylalkoxysilane, forming a gel, reacting the gel with at least an amine or amine containing compound, and drying the resulting gel to obtain an aerogel;

wherein the aerogel comprises at least an open pore accessible to carbon dioxide.

17. The amine-functionalized hydrophobic silica aerogel of claim 1, produced by the following process:

surface-treating a wet gel or an aerogel prepared from a monoalkylalkoxysilane or a dialkylalkoxysilane with an amine or an amine containing compound.

18. The aerogel of claim 17 where the amine containing compound is selected from tetraethylenepentamine (TEPA), polyethyleneimine (PEI) or combinations thereof.

19. The sorbent of claim 6, wherein the sorbent has no more than a 10% degradation in capture rate after exposing the sorbent to temperatures up to 130°

C. through up to 500 capture-regeneration cycles.

20. The sorbent of claim 6, wherein the sorbent has no more than a 10% degradation in capture rate after exposing the sorbent to temperatures up to 130°

C. through up to 1000 capture-regeneration cycles.