Direct air capture (DAC) carbon dioxide (CO2) sequestration methods and systems
Methods of sequestering carbon dioxide (CO 2 ) are provided. Aspects of the methods include contacting an aqueous capture liquid, such as an aqueous capture ammonia, with a direct air capture (DAC) generated gaseous source of CO 2 under conditions sufficient to produce an aqueous carbonate liquid, such as an aqueous ammonium carbonate. The aqueous carbonate liquid is then combined with a cation source under conditions sufficient to produce a solid CO 2 sequestering carbonate. Also provided are systems configured for carrying out the methods.
1. A method of sequestering CO 2 from a gaseous source of CO 2 , the method comprising:
a) contacting an aqueous capture ammonia with a direct air capture (DAC) generated gaseous source of CO 2 under conditions sufficient to produce an aqueous carbonate;
b) combining a cation source and the aqueous carbonate under conditions sufficient to produce a CO 2 sequestering carbonate and an aqueous ammonium salt; and
c) regenerating aqueous capture ammonia by contacting the aqueous ammonium salt with an alkalinity source, wherein the regenerated aqueous capture ammonia comprises ammonia and water; and
d) producing the aqueous carbonate using the regenerated aqueous capture ammonia;
to sequester CO 2 from the gaseous source of CO 2 .
2. The method according to claim 1 , wherein regenerating the aqueous capture ammonia from the aqueous ammonium salt comprises distillation.
3. The method according to claim 2 , wherein the distillation comprises heating the aqueous ammonium salt in the presence of the alkalinity source.
4. The method according to claim 1 , wherein the alkalinity source is produced by dissolving a geomass.
5. The method according to claim 4 , wherein the geomass comprises demolished, recycled or returned concrete.
6. The method according to claim 4 , wherein the dissolving of geomass comprises employing microwave energy.
7. The method according to claim 1 , wherein the cation source comprises an alkaline earth metal cation.
8. The method according to claim 7 , wherein the cation source is a source of divalent cations.
9. The method according to claim 8 , wherein the divalent cations comprise alkaline earth metal cations.
10. The method according to claim 9 , wherein the divalent alkaline earth metal cations are selected from the group consisting of Ca 2+ and Mg 2+ , and combinations thereof.
11. The method according to claim 1 , wherein the method comprises producing a CO 2 gaseous product.
12. The method according to claim 11 , wherein the CO 2 gaseous product is purified.
13. The method according to claim 1 , wherein the method comprises conveying the regenerated aqueous capture ammonia to the DAC generated gaseous source of CO 2 .
14. A method of sequestering CO 2 from a gaseous source of CO 2 , the method comprising:
a) contacting an aqueous capture liquid comprising ammonia and water with a direct air capture (DAC) generated gaseous source of CO 2 ;
b) regenerating the aqueous capture liquid using an alkalinity source; and
c) recycling the regenerated aqueous capture liquid by conveying the regenerated capture liquid to the DAC generated gaseous source of CO 2 ;
to sequester CO 2 from the gaseous source of CO 2 .