Electrochemical capture of Lewis acid gases

Patent metadata

Field	Value
Publication number	US-11219858-B2
Application number	US-202017005250-A
Country	US
Kind code	B2
Filing date	Aug 27, 2020
Priority date	Aug 28, 2019
Publication date	Jan 11, 2022
Grant date	Jan 11, 2022

Abstract

Methods, apparatuses, and systems related to electrochemical capture of Lewis acid gases from fluid mixtures are generally described. Certain embodiments are related to electrochemical methods involving selectively removing a first Lewis acid gas from a fluid mixture containing multiple types of Lewis acid gases (e.g., a first Lewis acid gas and a second Lewis acid gas). Certain embodiments are related to electrochemical systems comprising certain types of electroactive species having certain redox states in which the species is capable of binding a first Lewis acid gas but for which binding with a second Lewis acid gas is thermodynamically and/or kinetically unfavorable. The methods, apparatuses, and systems described herein may be useful in carbon capture and pollution mitigation applications.

First claim

What is claimed is:

1. An electrochemical apparatus, comprising:
a chamber comprising a negative electrode in electronic communication with an electroactive species, the chamber constructed to receive a fluid mixture;
wherein, in at least one conductive medium, the electroactive species has:
an oxidized state; and
at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with a second Lewis acid gas comprising one or more species chosen from carbon dioxide, nitrogen oxides, R 3 B, or R 2 S is thermodynamically and/or kinetically unfavorable at at least one temperature, wherein each R is independently H, branched or unbranched C1-C8 alkyl, aryl, cyclyl, heteroaryl, or heterocyclyl.

2. The electrochemical apparatus of claim 1 , wherein the electroactive species is present in a liquid within the electrochemical apparatus.

3. The electrochemical apparatus of claim 1 , wherein the electroactive species is immobilized on the negative electrode.

4. The electrochemical apparatus of claim 1 , wherein the electroactive species comprises one or more organic species chosen from optionally-substituted quinone, optionally-substituted thiolate, an optionally-substituted bipyridine, an optionally-substituted phenazine, and an optionally-substituted phenothiazine.

5. The electrochemical apparatus of claim 1 , wherein in the at least one reduced state the electroactive species comprises a moiety having a pK a that is greater than or equal to the pK a of the first Lewis acid gas and less than the pK a of carbon dioxide.

6. The electrochemical apparatus of claim 1 , wherein the first Lewis acid gas is a gas chosen from sulfur dioxide (SO 2 ), sulfur oxides (SO x ), nitrogen oxides (NO x ), R 2 S, carbonyl sulfide (COS), R 3 B, boron trifluoride (BF 3 ), or a combination thereof, wherein each R is independently H, branched or unbranched C1-C8 alkyl, aryl, cyclyl, heteroaryl, or heterocyclyl.

7. The electrochemical apparatus of claim 1 , wherein R 2 S is hydrogen sulfide (H 2 S).

8. The electrochemical apparatus of claim 1 , wherein R 3 B is a borane.

9. The electrochemical apparatus of claim 8 , wherein the borane is BH 3 .

10. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is thermodynamically unfavorable at at least one temperature.

11. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is kinetically unfavorable at at least one temperature.

12. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is thermodynamically unfavorable at at least one temperature greater than or equal to 223 K.

13. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is kinetically unfavorable at at least one temperature greater than or equal to 223 K.

14. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is thermodynamically unfavorable at at least one temperature greater than or equal to 223 K and less than or equal to 573 K.

15. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is kinetically unfavorable at at least one temperature greater than or equal to 223 K and less than or equal to 573 K.

16. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is thermodynamically unfavorable at at least one temperature greater than or equal to 223 K and less than or equal to 373 K.

17. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is kinetically unfavorable at at least one temperature greater than or equal to 223 K and less than or equal to 373 K.

18. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is thermodynamically unfavorable at 298 K.

19. The electrochemical apparatus of claim 1 , wherein the electroactive species has at least one reduced state in which the electroactive species is capable of bonding with a first Lewis acid gas, but for which a reaction with carbon dioxide is kinetically unfavorable at 298 K.

20. The electrochemical apparatus of claim 1 , wherein the negative electrode is part of an electrochemical cell comprising the negative electrode and a positive electrode.

21. The electrochemical apparatus of claim 20 , wherein the negative electrode comprises an electroactive composite layer comprising the electroactive species.

22. The electrochemical apparatus of claim 20 , wherein the electroactive species is a first electroactive species, and the positive electrode comprises a second electroactive species.

23. The electrochemical apparatus of claim 1 , further comprising the conductive medium.

24. The electrochemical apparatus of claim 1 , wherein the conductive medium comprises a non-volatile electrolyte.

25. The electrochemical apparatus of claim 1 , wherein the conductive medium comprises a liquid.

26. The electrochemical apparatus of claim 1 , wherein the conductive medium comprises a room temperature ionic liquid.

27. The electrochemical apparatus of claim 1 , wherein the electrochemical apparatus comprises a plurality of the chambers fluidically connected in series.

28. A method, comprising:
applying a potential difference across an electrochemical cell;
exposing a fluid mixture comprising a first Lewis acid gas and a second Lewis acid gas to the electrochemical cell; and
removing an amount of the first Lewis acid gas from the fluid mixture during and/or after the applying the potential difference;
wherein the method involves removing from the fluid mixture essentially none or less than or equal to 10% of the second Lewis acid gas present in the fluid mixture by mole percent.

29. The method of claim 28 , wherein the first Lewis acid gas is a gas chosen from sulfur dioxide (SO 2 ), sulfur oxides (SO x ), nitrogen oxides (NO x ), R 2 S, carbonyl sulfide (COS), R 3 B, boron trifluoride (BF 3 ), or a combination thereof,

Assignees

• Massachusetts Inst Technology

Inventors

• Voskian Sahag
• Hatton Trevor Alan
• Halliday Cameron G

Classifications

• F23J2215/50

  Carbon dioxide · CPC title

• F23J2215/20

  Sulfur; Compounds thereof · CPC title

• F23J2215/10

  Nitrogen; Compounds thereof · CPC title

• F23J15/02

  of purifiers, e.g. for removing noxious material (traps for solid residues F23J3/04) · CPC title

• C25B11/085

  Organic compound · CPC title