Sorbent and method for carbon dioxide capture and recovery
A functionalized carbon dioxide sorbent of a functionalized graphene oxide (fGO) substrate having substitution sites substituted with a functional group. The functional groups can be secondary or tertiary amines, a phosphate, a sulfonate or magnetite. The sorbent can have a binder intermixed with the fGO substrate, in the form of pellets, using a hydroxyethyl cellulose binder. A method using the functionalized sorbent provided captures a CO 2 from a flue gas, by passing the flue gas containing moisture and a concentration of CO 2 across the sorbent packed bed of the functionalized sorbent to adsorb selectively a portion of CO 2 in the flue gas onto the fGO of the sorbent. The captured CO 2 can be desorbed from the sorbent by exposure to a fluid at elevated temperature and/or reduced pressure conditions sufficient to desorb the CO 2 , and separating and concentrating the desorbed CO 2 from the fluid. The functional moieties can be at least one of a primary and secondary amine, and a secondary function group of tertiary amines, phosphates, sulfonates and/or magnetite.
1 . A method for capturing selectively carbon dioxide from a flue stream, the method comprising the steps of:
a. providing a functionalized carbon dioxide sorbent that comprises a functionalized graphene oxide substrate having a plurality of substitution sites substituted with a plurality of functional groups, wherein the plurality of functional groups include (i) at least one of a primary amine and a secondary amine, and (ii) a tertiary amine;
b. passing a flue gas containing moisture and a concentration of carbon dioxide (CO 2 ) across the sorbent; and
c. adsorbing selectively a portion of CO 2 in the flue gas onto the fGO of the sorbent to reduce the concentration of the CO 2 content of the flue gas, and generating a partially-saturated sorbent comprising adsorbed CO 2 .
2 . The method according to claim 1 wherein the flue gas containing a concentration of carbon dioxide (CO 2 ) is introduced into the packed bed of the sorbent at a temperature of about 40-80° C.
3 . The method according to claim 2 wherein the temperature of the fluid exposed to the partially-saturated sorbent is about 70-125° C. to at least partially desorb CO 2 from the partially-saturated sorbent.
4 . The method according to claim 3 , further including a step of exposing the partially-desorbed sorbent to a vacuum of about 0.1 bar or less to extract a further portion of CO 2 remaining on the sorbent.
5 . The method according to claim 1 wherein the sorbent is in the form of a pellet.
6 . The method according to claim 5 wherein the sorbent pellet comprises a binder intermixed with the functionalized graphene substrate.
7 . The method of claim 1 , for releasing the captured carbon dioxide, further including the steps of:
d. exposing the partially-saturated sorbent to a fluid at conditions of temperature and pressure sufficient, to desorb the adsorbed CO 2 from the partially-saturated sorbent into the fluid; and
e. separating and concentrating the desorbed CO 2 from the fluid.
8 . The method according to claim 1 wherein the plurality of functional groups further include one or more of a phosphate, a sulfonate, a nitrile, a hydroxyl, and magnetite.
9 . The method according to claim 1 wherein the weight range of oxygen in the graphene oxide is from 5% to 50%.
10 . A method for capturing selectively carbon dioxide from a flue stream, the method comprising the steps of:
a. providing a packed bed of a functionalized carbon dioxide sorbent that comprises a functionalized graphene oxide (fGO) substrate having a plurality of substitution sites substituted with a plurality of functional groups, wherein the plurality of functional groups include (i) at least one of a primary amine and a secondary amine, and (ii) a tertiary amine;
b. passing a flue gas containing moisture and a concentration of carbon dioxide (CO 2 ) across the sorbent; and
c. adsorbing selectively a portion of CO 2 in the flue gas onto the fGO of the sorbent to reduce the concentration of the CO 2 content of the flue gas, and generating a partially-saturated sorbent comprising adsorbed CO 2 .
11 . The method according to claim 10 wherein the plurality of functional groups further include one or more of a phosphate, a sulfonate, a nitrile, a hydroxyl, and magnetite.
12 . The method according to claim 11 wherein the flue gas containing a concentration of carbon dioxide (CO 2 ) is introduced into the packed bed of the sorbent at a temperature of about 40-80° C.
13 . The method according to claim 12 wherein the temperature of the fluid exposed to the partially-saturated sorbent is about 70-125° C. to at least partially desorb CO 2 from the partially-saturated sorbent.
14 . The method according to claim 13 , further including a step of exposing the partially-desorbed sorbent to a vacuum of about 0.1 bar or less to extract a further portion of CO 2 remaining on the sorbent.
15 . The method according to claim 10 wherein the sorbent is in the form of a pellet.
16 . The method according to claim 15 wherein the sorbent pellet comprises a binder intermixed with the functionalized graphene substrate.
17 . The method of claim 10 , for releasing the captured carbon dioxide, further including the steps of:
d. exposing the partially-saturated sorbent to a fluid at conditions of temperature and pressure sufficient, to desorb the adsorbed CO 2 from the partially-saturated sorbent into the fluid; and
e. separating and concentrating the desorbed CO 2 from the fluid.
18 . The method according to claim 10 wherein the weight range of oxygen in the graphene oxide is from 5% to 50%.