Apparatus, system, and method for co2 capture

Abstract

Embodiments of the present disclosure provide for apparatus, systems, and methods for CO2 capture. The apparatus, systems, and methods for CO2 capture use contactors comprising a sorbent, a substrate, and one or more dopants associated with the substrate.

Description

WGS Docket No.: Z1034.70005WQ00APPARATUS, SYSTEM, AND METHOD FOR CO2 CAPTURECROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No.63 / 778,943, entitled “APPARATUS, SYSTEM, AND METHOD FOR CO2CAPTURE,” filed March 27, 2025, the contents of which are incorporated herein in their entirety.FIELD OF THE INVENTION

[0002] Exemplary embodiments of the present disclosure relate to apparatus, systems and methods to capture CO2.BACKGROUND

[0003] Carbon capture and storage methods to reduce greenhouse gas emissions have become an area of increasing importance. Of particular interest are direct air capture (DAC) methods, which remove CO2 from the atmosphere and gas mixtures and may be used to address specific emission sources, such as cars and planes.

[0004] Many DAC technologies rely on solid contactors with sorbents as a medium to perform the separation of CO2 from the air or other gas mixtures. These sorbents are applied in temperature swing processes, where at low temperature CO2 binds to the sites within them, and then at high temperature the CO2 is released into a concentrated product that may be sequestered or sold. Many DAC sorbents utilize amines to bind CO2 in this manner.

[0005] Amines that are used to bind CO2 in DAC may slowly oxidize in air from ambient oxygen. This effect is exacerbated in process cycles that raise the temperature of the contactor to remove bound CO2, thereby creating accelerated oxidative degradation that reduces the lifetime of the contactors.SUMMARY

[0006] The purpose and advantages of the disclosed subject matter will be set forth in and are apparent from the description that follows, as well as will be learned by practice of the disclosed subject matter. Additional advantages of the disclosed subject matter may be realized and-1- 15083520.1WGS Docket No.: Z1034.70005WQ00attained by the devices particularly pointed out in the written description and claims hereof, as well as from the appended drawings.

[0007] A primary object of the present disclosure is to provide a contactor with increased lifetime, such as by reducing the oxidative degradation of sorbent materials. For example, some embodiments of the present disclosure are directed to methods of incorporating dopants into and / or onto the substrate of a contactor to alter the surface, structure, and / or electronic properties of the substrate that a sorbent interacts with.

[0008] Some embodiments of the disclosure are directed to a CCb-capturing contactor. In some embodiments, the CCb-capturing contactor comprises a sorbent, a substrate, and one or more dopants associated with the substrate. In some embodiments, the one or more dopants include a metal oxide, metal hydroxide, metal nitrate, metal phosphate, metal hydride, metal nitrite, metal phosphite, or combinations thereof. In some embodiments, the one or more dopants include lithium, sodium, potassium, silicon, titanium, phosphorus, cesium, magnesium, calcium, strontium, barium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or combinations thereof. In some embodiments, the one or more dopants are incorporated within the substrate, on a surface of the substrate, or both. In some embodiments, the one or more dopants are incorporated into the substrate. For example, the substrate comprises a scaffold and a sorbent retainer coated onto a surface of the scaffold, wherein the one or more dopants are included in the sorbent retainer. Alternatively, or additionally, for example, the one or more dopants are included in a formulation that is extruded to form the substrate.

[0009] Some embodiments of the disclosure are directed to a method of making a contactor for CO2 capture. In some embodiments, the method comprises contacting a surface of a substrate or a formulation of the substrate with a solution of one or more dopants. In some embodiments, the method further comprises removing excess liquid of the solution. In some embodiments, the method further comprises incorporating a sorbent with the substrate. In some embodiments, the method further comprises heating the substrate. In some embodiments, the substrate is heated before incorporating the sorbent with the substrate.

[0010] Some embodiments of the disclosure are directed to a method of capturing CO2 from a gas (e.g., a gas mixture). In some embodiments, the method comprises introducing the gas to a contactor, the contactor including a sorbent, a substrate, and one or more dopants associated with-2- 15083520.1WGS Docket No.: Z1034.70005WQ00the substrate. In some embodiments, the method further comprises, after introducing the gas to the contactor, heating the contactor to release captured CO2. In some embodiments, the method further comprises collecting the released CO2.

[0011] Some embodiments of the disclosure are directed to a system for capturing CO2 from a gas. In some embodiments, the system comprises a first device configured to introduce the gas to a contactor, the contactor including a sorbent, a substrate, and one or more dopants associated with the substrate. In some embodiments, the system further comprises a second device configured to heat the contactor to release captured CO2. In some embodiments, the system further comprises a third device configured to collect the released CO2.

[0012] It is to be understood that both the foregoing general description and the following detailed description and drawings are examples and are provided for purpose of illustration and not intended to limit the scope of the disclosed subject matter in any manner.The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the embodiments of the disclosed subject matter. Together with the description, the drawings serve to explain the principles of the disclosed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The subject matter of the application will be more readily understood from the following detailed description when read in conjunction with the accompanying drawings, in which:

[0014] FIG. 1 illustrates a contactor with a sorbent-impregnated honeycomb monolith substrate, according to some embodiments of the disclosure;

[0015] FIG. 2 illustrates oxidation curves for alumina substrates including PEI, according to some embodiments of the disclosure;

[0016] FIG. 3 illustrates rates of oxidation of alumina substrates including PEI as a function of dopant surface coverage, according to some embodiments of the disclosure;

[0017] FIG. 4 illustrates rates of oxidation of substrates including PEI as a function of dopant electronegativity, according to some embodiments of the disclosure.DETAILED DESCRIPTION-3- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0018] Embodiments of the present disclosure provide for novel and cost-effective apparatus, systems, and methods for CO2 capture. For example, embodiments disclosed herein include novel contactors used for CO2 capture and systems and methods of using the disclosed contactors to capture CO2. The apparatus, systems, and methods of the present disclosure may be advantageous since there is an improvement in the oxidative stability and lifetime of the contactors.

[0019] In certain embodiments, a contactor used for CO2 capture comprises a sorbent and a substrate that may hold the sorbent for CO2 capture. It should be appreciated that the CO2 capture may be accomplished via adsorption and / or absorption.

[0020] The sorbent can be disposed on the surface of the substrate, and / or within pores of the substrate, and / or on exterior surface of the substrate or any combination thereof. The sorbent can be, for example, a coating on the surface of the substrate, a monolayer on the surface of the substrate, a self-assembled monolayer on the surface of the substrate, a bulk phase within the pores of the substrate, and the like. The substrate may include a sorbent retainer that immobilizes the sorbent within the contactor (e.g., as described below). The substrate may also include a scaffold that provides physical structure to the contactor.

[0021] In certain embodiments, the sorbent has one or more CO2 binding moieties which may interact with CO2 during CO2 capture. In certain embodiments, the CCh-adsorbed (and / or absorbed) sorbent may be processed to remove the bound CO2 and reused for CO2 capture, the process of which may be referred to as sorbent regeneration. Sorbent regeneration uses thermal energy, pressure, and / or vacuum to restore the capture capacity of sorbents used for carbon capture, such as by raising the temperature of the CCh-adsorbed (and / or absorbed) sorbent to facilitate the removal of bound CO2. It thus may be advantageous to improve the stability of the sorbent during the sorbent regeneration process. It also may be advantageous to improve the stability of the sorbent to conditions relevant to storage of the sorbents when they are not being utilized in a process or plant.

[0022] During the sorbent regeneration process, desorbed CO2 may be present at different concentrations with respect to oxygen, and the presence of oxygen at elevated temperatures may impact the stability of the sorbent. Separately, evaluating the oxidative stability of the sorbent with air may be a useful way to evaluate the shelf life of the sorbent when it is stored at ambient conditions.-4- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0023] In certain embodiments, the oxidative stability of the sorbent may be improved by treating the substrate and associating one or more dopants with the substrate. Contactors with the sorbent and the treated substrate may have increased stability to oxidative degradation, and thereby have a longer commercial lifetime than contactors without the improvement.

[0024] In certain embodiments, a contactor is activated (e.g., for use in CO2 capture applications) when it contains the sorbent within the volume and / or upon the surface of pores (e.g., macropores, mesopores, and / or micropores) of the substrate at a specific loading. The specific loading of the sorbent may be dependent on the pore volume (e.g., macropore, mesopore, and / or micropore volume) of the substrate, and the specific loading may be expressed as a percentage of the pore volume occupied by the sorbent. The specific loading of the sorbent may be different when the contactor is deployed in a particular climate or environment.

[0025] The contactor may be structured or unstructured. Unstructured contactors may not have a specific form factor at standard conditions, but are capable of retaining a sorbent for use in CO2 capture applications (e.g., unstructured contactors may include fibrous materials or fluidized beds). Structured contactors may have a specific form factor and may be formed into a solid body at standard conditions. In some embodiments, structured contactors take the form of a solid body, wherein the solid body may comprise predominantly of the sorbent retainer with optionally other components that allow the structured contactors to remain a stable body at standard conditions. In some embodiments, structured contactors include a coating of the sorbent retainer on a scaffold, whereby the scaffold has a different composition than the coating and provides mechanical stability to the coating.

[0026] In some embodiments, the sorbent contains CO2 binding molecules with CO2 binding moieties. In some embodiments, the CO2 binding molecules may be an amine or an amine polymer. The amine or amine polymer may contain primary amines, secondary amines, tertiary amines, or a mixture of any combination of primary, secondary, and / or tertiary amines. The amine polymer may be branched, hyperbranched, dendritic, or linear. In some embodiments, the CO2 binding moieties are the amine moieties on the amine molecule or polymer. The amine moieties may interact with CO2 to form carbamate, carbonate, or bicarbonate species.

[0027] Primary amines have the chemical structure NH2R1, secondary amines have the chemical structure NHR1R2, and tertiary amines have the chemical structure NR1R2R3, wherein-5- 15083520.1WGS Docket No.: Z1034.70005WQ00R1, R2, and R3are the same or different and independently selected from substituted or unsubstituted, isomeric or non-isomeric, straight or branched, acyclic or cyclic alkyl groups.

[0028] Linear amine polymers contain only primary amines, secondary amines, or both primary and secondary amines. The ratio of secondary to primary amines may be about 0.5 to 10,000. The linear amine polymer may have a molecular weight of about 100 to 100,000 g / mol, about 200 to 30,000 g / mol, or about 600 to 5,000 g / mol.

[0029] Branched amine polymers contain any number of primary, secondary, and tertiary amines. The ratio of primary, secondary, and tertiary amines may be about 10:80:10 to 60:10:30, about 60:30:10 to 30:50:20, or about 45:45:10 to 35:45:20. The chemical structures of branched amine polymers may vary greatly and may be very complex. The branched amine polymer may have a molecular weight of about 100 to 100,000 g / mol, about 200 to 30,000 g / mol, or about 600 to 5,000 g / mol.

[0030] Dendritic amine polymers contain only primary and tertiary amines, wherein groups of repeat units are arranged in a manner that is necessarily symmetric in at least one plane through the center (e.g., core) of the molecule, and wherein each polymer branch is terminated by a primary amine, and each branching point is a tertiary amine. The core or central linkage is the same as the branching amines (e.g., ethylenimine core and ethylenimine branches, propylenimine core and propylenimine branches). The ratio of primary to tertiary amines may be about 1 to 3. The dendritic amine polymer may have a molecular weight of about 100 to 100,000 g / mol, about 200 to 30,000 g / mol or about 280 to 3,000 g / mol.

[0031] Hyperbranched amine polymers have structures resembling dendritic amine polymer but contain defects in the form of secondary amines (e.g., linear subsections as would exist in a branched polymer), in such a way that provides a random structure instead of a symmetric structure. In a hyperbranched structure, the ratio of primary to secondary to tertiary may be about 65:5:30 to 30:10:60. The hyperbranched amine polymer may have a molecular weight of about 100 to 100,000 g / mol, about 200 to 30,000 g / mol or about 600 to 10,000 g / mol.

[0032] The amine polymer may be a polymer or copolymer of polyethylenimine (PEI), polypropylenimine, polyallylamine, polyvinylamine, polyglycidylamine, polystyrene-divinylbenzene polymer functionalized with amines such as alkylbenzylamine moieties, or other amine polymers, where each may be branched, hyperbranched, dendritic, linear, or a mixture thereof.-6- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0033] The size (e.g., length, molecular weight), amount (e.g., number of distinct amine polymers), and / or type of amine polymer may be selected based on the desired characteristics of the porous structure of the substrate e.g., CO2 absorption, regenerative properties, oxidative stability, loading, and the like).

[0034] In some embodiments, the CO2 binding molecules of the sorbent may be present on and / or within the substrate in a variety of ways. For example, the CO2 binding molecules may be applied or incorporated to form a layer of the sorbent on a substrate, such as on the surface of pores of the substrate and / or within pores of the substrate. In certain embodiments, independent of or used in combination with other embodiments such as those described above, the CO2 binding molecules may be used to form a part of or all of the sorbent, where the sorbent functions as described herein. Various combinations are contemplated and are part of the present disclosure. Additional ways in which to apply, use, or incorporate the sorbent are described herein and below.

[0035] As described herein, the contactor used for CO2 capture may include a sorbent and a substrate. In certain embodiments, the contactor may include one or more dopants associated with the substrate. The dopants may be present within the bulk of the substrate, on the surface of the substrate, or both within the bulk of the substrate and on the surface of the substrate. The surface may be the surface of pores and / or other surfaces that the sorbent contacts or interacts with. In some embodiments, the substrate is physically impregnated with the sorbent, while in other embodiments, the sorbent is covalently bonded to the surface of the substrate. When the sorbent is covalently bonded to the surface of the substrate, the sorbent may be bonded or not bonded to a dopant site on the surface of the substrate.

[0036] In certain embodiments, the amount of dopant that is incorporated into and / or onto the substrate is not less than 0.5% by weight of the substrate, not less than 1% by weight of the substrate, not less than 1.5% by weight of the substrate, not less than 2% by weight of the substrate, and not greater than 10% by weight of the substrate (e.g., 0.5 to 10%, 1 to 10%), not greater than 8% by weight of the substrate (e.g., 0.5 to 8%, 1.5 to 8%), not greater than 5% by weight of the substrate (e.g., 5 to 10%, 5 to 8%), not greater than 2.5% by weight of the substrate (e.g., 0.5 to 2.5% or 1 to 2.5%), or not greater than 1% by weight of the substrate (e.g., 0.5 to 1%) and all ranges covered therein.-7- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0037] In certain embodiments, the amount of dopant that is incorporated into and / or onto the substrate is not less than or equal to 0.5 monolayers, not less than 1 monolayer, not less than 2.5 monolayers, not less than 5 monolayers, not less than 10 monolayers, and not greater than 5 monolayers, not greater than 10 monolayers, not greater than 15 monolayers, not greater than 20 monolayers and all ranges covered therein (e.g., 0.5 to 20 monolayers, 0.5 to 5 monolayers, 1 to 20 monolayers, 2.5 to 15 monolayers, 2.5 to 20 monolayers, 5 to 10 monolayers, 10 to 20 monolayers, and the like). A monolayer of coverage is defined as the surface area of the substrate associated with dopants being equal to the surface area of the substrate.

[0038] In some embodiments, the dopants are metal elements. In some embodiments, the dopants are metal salts having a Pauling electronegativity less than 2.5, less than 2.2, less than 2, less than 1.5, or less than 1.35. In certain embodiments, the metal elements may include lithium, sodium, potassium, silicon, titanium, cesium, magnesium, calcium, strontium, barium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or combinations thereof. In some embodiments, the dopants are metal oxides or hydroxide compounds (as described herein).

[0039] In some embodiments, the dopants include phosphorus. In some embodiments, the dopants can include salts of ammonium phosphates, sodium phosphates, potassium phosphate, calcium phosphate, magnesium phosphate, or combinations thereof. In some embodiments, the dopants include phosphoric acid, ammonium phosphate, phosphorus pentoxide, sodium phosphite, or combinations thereof.

[0040] Not intending to be bound by theory, the incorporation of dopants into and / or onto the substrate may alter the surface, structure, and / or electronic properties that the sorbent interacts with, resulting in a contactor that is more robust to oxidative conditions (e.g., thereby increasing the lifetime of the contactor). For example, the dopants may alter the surface chemistry and / or electronic properties of the substrate, resulting in a greater number of basic sites and a smaller number of acidic sites on the surface of and / or within the substrate. As another example, the dopants may be introduced into the lattice matrix of the substrate, thus altering its acidity.

[0041] The present disclosure provides for methods of making a substrate for a contactor of CO2 capture, wherein the substrate includes or is otherwise associated with dopants. In general, conventional methods of making the substrate use an acidic component (e.g., citric acid, formic acid, acetic acid, nitric acid, or phosphoric acid) in the peptization of a powder to form a stable-8- 15083520.1WGS Docket No.: Z1034.70005WQ00slurry, paste, or other precursor mixture for the substrate at low pH. The inventors of the present invention unexpectedly discovered that the oxidative stability of the contactor may be improved by making the substrate using, for example, a basic component. The basic component may include, for example, solutions containing metal oxide, metal hydroxide, metal nitrate, metal phosphate, metal hydride, metal nitrite, metal phosphite, or combinations thereof.

[0042] The basic component may include solutions including metal oxide compounds such as lithium oxide, sodium oxide, potassium oxide, silica, titania, rubidium oxide, cesium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, yttrium oxide, lanthanum oxide, praseodymium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, or combinations thereof.

[0043] The basic component may include solutions including hydroxide compounds such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, lanthanum hydroxide, cerium hydroxide, and combinations thereof. In certain embodiments, the basic component may include solutions containing hydroxide compounds such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, lanthanum hydroxide, cerium hydroxide, and combinations thereof.

[0044] The basic component may include solutions including nitrate salts such as lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, barium nitrate, yttrium nitrate, lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, terbium nitrate, dysprosium nitrate, holmium nitrate, erbium nitrate, thulium nitrate, ytterbium nitrate, lutetium nitrate, and combinations thereof. In certain embodiments, the basic component may include solutions containing nitrate salts such as lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, calcium nitrate, strontium nitrate, barium nitrate, lanthanum nitrate, cerium nitrate, and combinations thereof.

[0045] The basic component may include solutions including nitrite salts such as sodium nitrite, potassium nitrite, calcium nitrite, and combinations thereof.-9- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0046] The basic component may include solutions including carbonate salts such as lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, yttrium carbonate, lanthanum carbonate, cerium carbonate, praseodymium carbonate, neodymium carbonate, samarium carbonate, europium carbonate, gadolinium carbonate, terbium carbonate, dysprosium carbonate, holmium carbonate, erbium carbonate, thulium carbonate, ytterbium carbonate, and combinations thereof. In certain embodiments, the basic component may include solutions containing carbonate salts such as lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, cesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, lanthanum carbonate, cerium carbonate, and combinations thereof.

[0047] The basic component may include solutions including phosphate salts such as lithium phosphate, sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate, strontium phosphate, barium phosphate, lanthanum phosphate, and combinations thereof. In certain embodiments, the basic component may include solutions containing phosphate salts such as lithium phosphate, sodium phosphate, potassium phosphate, calcium phosphate, strontium phosphate, barium phosphate, lanthanum phosphate, and combinations thereof. In certain embodiments, the basic component may include solutions containing metal hydrides such as lithium borohydride, sodium hydride, potassium hydride, calcium hydride, or other metal hydrides and combinations thereof.

[0048] In some embodiments, the basic component is used together with other components to form a stable slurry, paste, or other precursors.

[0049] In certain embodiments, the methods of making a contactor for CO2 capture include creating a precursor material containing a dispersed mixture (e.g., a paste or slurry including one or more types of materials as described herein and below like ceramics, metal, metal oxide, plastic, and the like). In certain embodiments, a substrate may be made from the precursor materials via methods such as extruding, molding, or printing (e.g., by additive manufacturing). In some other embodiments, a coating made from the precursor material may be disposed into a scaffold and / or onto a scaffold. Optionally, the methods may also include drying the substrate by exposing the substrate with the coating on it to a temperature of not greater than 150 °C. The prepared substrate as described herein may be calcined, such as by exposing the substrate to a temperature of about 1200 °C or less.-10- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0050] In certain embodiments, the substance of the contactor may be modified to include dopants within and / or on the surface of the substrate. For example, the method includes contacting a surface (e.g., a surface that contacts the sorbent and / or the gas including the CO2) of the substrate with a dopant-containing solution (e.g., immersing the substrate into an aqueous solution including one or more dopants). For example, the dopant-containing solution may include metal oxide, metal hydroxide, metal nitrate, metal phosphate, metal hydride, metal nitrite, metal phosphite, metal carbonate, or combinations thereof.

[0051] In some embodiments, the substance of the contactor may be manufactured to include dopants on and / or within the substrate. For example, the method includes adding one or more dopants (e.g., in a dopant-containing solution) into a sorbent retainer formulation (e.g., a washcoat formulation) and coating the sorbent retainer formulation onto a scaffold (e.g., the scaffold and the sorbent retainer together forming the substrate). In some embodiments, after coating the sorbent retainer onto the scaffold, the substrate is heated. In some embodiments, after heating the substrate, a sorbent is incorporated. In some embodiments, the method includes adding one or more dopants into a formulation that is extruded, molded, or printed (e.g., by additive manufacturing) to form the substrate.

[0052] It should be appreciated that other methods may be used to associate one or more dopants with a substrate (e.g., with the sorbent retainer of the substrate). For example, the one or more dopants may be associated with a substrate (and / or the sorbent retainer of the substrate) through incipient wetness impregnation, atomic layer deposition, atomic vapor deposition, precipitation (or coprecipitation), sol-gel, decomposition (e.g., of single source precursors), and / or microwave irradiation methods.

[0053] The dopant-containing solution may include hydroxide salts such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, lanthanum hydroxide, cerium hydroxide, and / or combinations thereof. In certain embodiments, the dopant-containing solution may include hydroxide salts such as lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, lanthanum hydroxide, cerium hydroxide, and combinations thereof.

[0054] The dopant-containing solution may include nitrate salts such as lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, magnesium nitrate, calcium nitrate,-11- 15083520.1WGS Docket No.: Z1034.70005WQ00strontium nitrate, barium nitrate, yttrium nitrate, lanthanum nitrate, cerium nitrate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, terbium nitrate, dysprosium nitrate, holmium nitrate, erbium nitrate, thulium nitrate, ytterbium nitrate, lutetium nitrate, and / or combinations thereof. In certain embodiments, the dopant-containing solution may include nitrate salts such as lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, cesium nitrate, calcium nitrate, strontium nitrate, barium nitrate, lanthanum nitrate, cerium nitrate, and combinations thereof.

[0055] The dopant-containing solution may include phosphate salts such as lithium phosphate, sodium phosphate, potassium phosphate, magnesium phosphate, calcium phosphate, strontium phosphate, barium phosphate, lanthanum phosphate, and combinations thereof. In certain embodiments, the dopant-containing solution may include phosphate salts such as lithium phosphate, sodium phosphate, potassium phosphate, calcium phosphate, strontium phosphate, barium phosphate, lanthanum phosphate, and combinations thereof. The dopant-containing solution may also include metal hydrides such as lithium borohydride, sodium hydride, potassium hydride, calcium hydride, or other metal hydrides.

[0056] The dopant-containing solution may be used to incorporate one or more types of dopants onto the surface or otherwise within the pores (e.g., macropores, mesopores, and / or micropores) of the substrate. In certain embodiments, the solvent in the dopant-containing solution may be evaporated to leave the dopants or dopant-containing compounds on or within the surface of the substrate. In certain embodiments, the dopant-containing substrate may be calcined at high temperature (e.g., above 200 °C, above 400 °C, above 600 °C) to further incorporate the dopants onto the surface or within the matrix of the substrate.

[0057] In certain embodiments, the sorbent may be incorporated into the dopant-associated substrate to form an active contactor (e.g., for use in CO2 capture applications). In certain embodiments, the dopants may be incorporated into the substrate in the same step as the sorbent by using a solution containing both dopants and the sorbent.

[0058] In certain embodiments, the substrate may be made of one or more types of materials such as ceramic, metal, metal oxide, plastic, cellulose, carbon, a zeolite, a metal organic framework (MOF), a porous organic framework (POF), a covenant organic framework (COF), a polymers of intrinsic microporosity (PIM), a polymer, a fibrous cellulose, fiberglass, boron--12- 15083520.1WGS Docket No.: Z1034.70005WQ00nitride fiber, and the like. In certain embodiments, the substrate may be made of materials that also include the sorbent.

[0059] The metal oxide substrate may be selected from cordierite, alumina (e.g., y-alumina, 9-alumina, 6-alumina), cordierite-a-alumina, silica, aluminosilicates, zirconia, germania, magnesia, titania, hafnia, silicon nitride, zircon mullite, spodumene, alumina- silica magnesia, zircon silicate, sillimanite, magnesium silicates, zircon, petalite, and combinations thereof. In embodiments where the metal oxide contains a formal charge, the charge may be balanced by appropriate counter-ions, such as cations of NR4, Na, K, Ca, Mg, Li, H, Rb, Sr, Ba, Cs or anions including phosphate, phosphite, sulfate, sulfate, nitrate, nitrite, chloride, bromide, carbonate, and the like. In certain embodiments, metal oxides may contain acid, base, and neutral sites on their surfaces, and dopants may alter the amount and strength of the acid and base sites on the surfaces.

[0060] The polymer substrate may be a polymer and / or copolymer of polyolefin(s), polyester(s), polyurethane(s), polycarbonate(s), polyetheretherketone(s), polyphenylene oxide(s), polyether sulfone(s), melamine(s), polyamide(s), polyvinylbenzene, polystyrene-divinylbenzene, polyurethane, polyacrylates, polystyrenes, polyacrylonitriles, polyimides, polyfurfural alcohol, phenol furfuryl alcohol, melamine formaldehydes, resorcinol formaldehydes, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurates, polyacrylamides, various epoxies, agar, and agarose, or combinations thereof.

[0061] The substrate may be porous (e.g., macroporous, mesoporous, microporous, or mixtures thereof (e.g., a macroporous surface may include mesopores and / or micropores; within one or more of the macropores, a mesoporous surface may include micropores, and so on)). The pores may extend through the porous structure or porous layer or only extend to a certain depth. In certain embodiments, the macropores of the porous structure may have pores having a diameter of about 100 nm to 10,000 nm, a length of about 500 nm to 100,000 nm and a volume of 0.2-1 cc / g. In certain embodiments, the mesopores of the porous structure may have pores having a diameter of about 5 nm to 100 nm, a length of about 10 nm to 10,000 nm, and a volume of 0.1-2 cc / g. In certain embodiments, the micropores of the porous structure may have pores having a diameter of about 0.5 to 5 nm, a length of about 0.5 nm to 1000 nm and a volume of about 0.1-1 cc / g.-13- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0062] The substrate may be porous and have a porosity (e.g., a percentage of pore space) of at least 90%, at least 85%, at least 80%, at least 75%, at least 70%, at least 65%, at least 60%, at least 55%, at least 50%, at least 45%, at least 40%, at least 35%, at least 30%, or about 30 to 90%, In certain embodiments, the substrate may have a surface area of 1 m2 / g or more, 10 m2 / g or more, 100 m2 / g or more, 150 m2 / g or more, 200 m2 / g or more, or 250 m2 / g or more, 500 m2 / g or more, 1000 m2 / g or more.

[0063] The substrate may have a porous structure, which may include a structure having pores inside or in its surface or a structure having a porous layer or coating on the surface of the structure, in which case the structure itself may or may not be porous. In certain embodiments, the sorbent may be physically impregnated in the internal pores of the porous structure of the substrate and not covalently bonded to the internal surface of the pores of the porous structure, may be grafted (e.g., covalently bonded directly or indirectly) to the internal surface of the pores of the porous structure, or a combination thereof. In certain embodiments, the sorbent may be covalently bonded (e.g., directly to the surface or via a linker group) to the surface of the substrate, which may include the internal surface of the pores of the porous structure. In regard to the sorbent being physically impregnated in the pores of the porous structure and not covalently bonded to the internal surface of the pores of the porous structure, the sorbent may be confined within the pores of the porous structure, but not bonded to the surface. In certain embodiments, the sorbent is present in a plurality of pores of the porous structure, wherein the sorbent has a loading of about 10% to 75% by weight of the substrate, determined by thermogravimetric analysis (TGA).

[0064] In certain embodiments, the substrate may include a surface layer on the surface of the pores of the substrate that may bond with the sorbent. The surface layer may include organically modified moieties (e.g., substituted alkyl groups, amines, thiols, phosphines, and the like) on the surface of the substrate, which the sorbent may be covalently bonded to directly and / or indirectly. The substrate may be carbon based, and the carbon-based substrate may have one or more of the following groups within or on the surface of the substrate: alkyl groups, amines, thiols, phosphines, and the like.

[0065] In certain embodiments, the sorbent and the substrate may form 100% of the contactor or less than 100% (e.g., each combination of ranges between about 10%, about 20%, about 30%, about 40%, about 50% and about 60%, about 70%, about 80%, about 90%, about 99%, such as-14- 15083520.1WGS Docket No.: Z1034.70005WQ00about 10-99%, about 10 to 80%, about 10 to 50%, about 50 to 99%, about 50 to 90%, about 50 to 80%), where a sufficient amount of the sorbent is on the surface of the contactor to adsorb (and / or absorb) the desired amount of CO2. The contactor may have a structure of a honeycomb, a laminate sheet, a foam, fibers, minimal surface solids, powder trays, pellets, powder, and the like or a combination of two or more of the foregoing.

[0066] The contactor may be porous and have a porosity of at least 90%, at least 85%, at least 80%, at least 75%, at least 70%, at least 65%, at least 60%, or about 60 to 90%. The porosity of the contactor may be comprised of macropores, mesopores, and / or micropores.

[0067] In some embodiments, the substrate of the contactor may be comprised entirely of the sorbent retainer when, for example, the precursor material for the substrate is titania, alumina, silica, or a combination thereof. When the substrate is comprised entirely of the sorbent retainer, it may be formed by extrusion, molding, 3D printing, and the like. The substrate may additionally comprise a scaffold. In other embodiments, the substrate may include a porous scaffold and may also include a porous sorbent retainer as a coating (e.g., a washcoat) applied on some or all parts of the porous scaffold, where the sorbent may be present in the pores of one or both of the porous scaffold and the porous coating. The scaffold may be porous and able to retain a sorbent (e.g., when the precursor material is titania, alumina, silica, or a combination thereof) or may have relatively low porosity (e.g., when the precursor material is extruded cordierite, corrugate fiberglass, an engineered material such as pleated metal or MOF / COF, or a combination thereof). The scaffold may be extruded, machined (e.g., corrugated fiberglass) or engineered (e.g., MOF).

[0068] In some embodiments, the porous coating of the sorbent retainer is a foam such as a polymeric foam (e.g., polyurethane foam, a polypropylene foam, a polyester foam, and the like), a metal foam, or a ceramic foam. The porous coating may include a metal-oxide layer (e.g., a foam). The metal-oxide layer may be, e.g., silica or alumina on the surface of the substrate. The porous coating may be present on the surface of the scaffold, within the pores or voids of the scaffold, or a combination thereof. The porous coating may be about 50 pm to 1500 pm thick and the pores may be of the dimension described above and herein.

[0069] The substrate may be made of a ceramic material such as cordierite, alumina e.g., y-alumina, 0-alumina, 6-alumina), cordierite-a-alumina, silica, aluminosilicates, zirconia, germania, magnesia, titania, hafnia, silicon nitride, zircon mullite, spodumene, alumina- silica-15- 15083520.1WGS Docket No.: Z1034.70005WQ00magnesia, zircon silicate, sillimanite, magnesium silicates, zircon, petalite, and combinations thereof. In some embodiments, the substrate may be made of metal or metal oxide, wherein the metal may be aluminum, titanium, stainless steel, a Fe-Cr alloy, or a Cr-Al-Fe alloy, or combinations thereof. In cases where the metal oxide materials contain formal charges, the charge may be balanced by appropriate counter-ions, such as cations of NR4, Na, K, Ca, Mg, Li, H, Rb, Sr, Ba, Cs, and the like, or anions including phosphate, phosphite, sulfate, sulfate, nitrate, nitrite, carbonate, chloride, bromide and the like.

[0070] The substrate may be made of a plastic material comprising a polymer and / or copolymer of polyolefin(s), polyester(s), polyurethane(s), polycarbonate(s), polyetheretherketone(s), polyphenylene oxide(s), polyether sulfone(s), melamine(s), polyamide(s), polyvinylbenzene, polystyrene-divinylbenzene, polyurethane, polyacrylates, polystyrenes, polyacrylonitriles, polyimides, polyfurfural alcohol, phenol furfuryl alcohol, melamine formaldehydes, resorcinol formaldehydes, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurates, polyacrylamides, various epoxies, agar, and agarose, or combinations thereof.

[0071] The substrate may be formed using materials disclosed herein without the sorbent or using the materials disclosed herein with the sorbent already incorporated. When formed without the sorbent, the sorbent may be incorporated into the substrate through an impregnation, grafting, or other functionalization technique.

[0072] In certain embodiments, the contactor may have a honeycomb structure such as a honeycomb monolith structure that includes channels. The honeycomb structure may have a regular, corrugated structure. The honeycomb structure may have a length and width on the order of centimeters to meters while the thickness may be on the order of millimeters to centimeters or more. In some embodiments, the honeycomb structure may be a flow-through substrate comprising open channels defined by walls of the channels. The channels may have about 50 to about 900 cells per square inch. The channels may be polygonal (e.g., square, triangular, hexagonal, octagonal) sinusoidal, circular, or the like, in cross-section. Along the length of the channel, the channel length may have a configuration that is straight, zig-zag, skewed, or herringbone in shape. The length of the channel may be 1 mm to 10s or 100s of cm or more. The channels may have walls that are perforated or louvered. In certain embodiments, the sorbent may be disposed in the pores of the honeycomb structure and / or in the pores of a porous layer on-16- 15083520.1WGS Docket No.: Z1034.70005WQ00the surface of the honeycomb structure. The honeycomb structure may have a geometric void fraction, otherwise known as the open face area, of between 0.3 to 0.95 or about 0.5 to 0.9.

[0073] The honeycomb structure may comprise an inlet end, an outlet end, and inner channels extending from the inlet end to the outlet end. In certain embodiments, the honeycomb structure comprises a multiplicity of cells extending from the inlet end to the outlet end, the cells being defined by intersecting cell or channel walls.

[0074] In certain embodiments, the contactor with the honeycomb structure may be made of ceramic. The sorbent may be coated or otherwise immobilized on the inside of the pores of the ceramic honeycomb structure and / or within a porous layer on the surface of the ceramic honeycomb structure. The porous coating may include a metal-oxide layer such as silica or alumina on the surface of the substrate. The metal-oxide layer may be mesoporous and / or macroporous. The honeycomb monolith may have a depth of 3 inches to 10 feet or about 3 and 24 inches.

[0075] The contactor may have a structure of laminate sheets. Laminate sheets may contain a one-dimensional wall structure, whereby sheets are stacked upon one another with space in between each sheet such that gas may flow between the sheets.

[0076] The contactor may have a foam structure. Foam structures may have an irregular channel structure surrounded by an irregular solid structure. The solid structure is interconnected such that the foam structure is self- standing.

[0077] The contactor may have a structure of a plurality of fibers. Fiber structures may have high aspect ratio, and in gas contacting applications the fiber structures may be arranged in a regular array amongst one another when supported at least on one end of the fiber. The fibers may be solid or hollow.

[0078] The contactor may have a structure of a minimal surface solid. Minimal surface solids are often used in packing for distillation and absorption systems to increase contact area with a material and a fluid. Minimal surface solids may have zero mean surface area and include shapes such as gyroids. Gyroids may be sinusoidal, for example.

[0079] The contactor may have a structure of a powder tray. Trays hold loose powder or pellets in powder tray structures to form a structured contactor without the materials forming a self-standing structure by themselves. Powder trays may be arranged in stacked layers to form sheets, thereby forming a structure similar to a laminate. These stacked layers may be created-17- 15083520.1WGS Docket No.: Z1034.70005WQ00using flexible sheets, stiff sheets, or other flat surface that is mounted on a stiff frame structure. Powders may be loose, free flowing solids with small characteristic particle diameter to provide a powdery consistency. Pellets are beads, balls, or other compacted structures used to provide structure and surface area to sorbents.

[0080] The contactor may have a structure of particle volumes. Particle volumes may be contained by one or more walls such that gas may pass through them while keeping the particles contained. Particle volumes may be arranged relative to other particle volumes such as to approximate a honeycomb, fiber, or other structures with a solid body.

[0081] The contactor is an efficient embodiment for capturing CO2 from ambient air or other gas mixtures (e.g., flue gas, exhaust gas, natural gas, or other gases containing CO2) because it may be engineered to provide high surface area and low pressure drop for the air processing. Contactors may take the forms of a honeycomb, a laminate sheet, a foam, fibers, minimal surface solids, powder trays, pellets, powder, and the like described above or a combination of two or more of the foregoing.

[0082] In certain embodiments, the contactor described above may be used in methods of capturing CO2 from ambient air or other gas mixtures (e.g., flue gas, exhaust gas, natural gas, or other gases containing CO2). The method may include introducing the ambient air to the contactor, heating the contactor (e.g., about 10 to 200° C above the regular contactor temperature to adsorb and / or absorb the CO2) to at least a first temperature to controllably release the CO2; and collecting the CO2 in a CO2 collection device. The temperature increase in the contactor may be performed by contacting the contactor with a gas at elevated temperature, contacting the contactor with a fluid at an elevated temperature, contacting the contactor with a heat exchanger with hot fluid or gas running through it by heating the walls of the container, vessel, or other containment device that contains the contactor, or by contacting the contactor with steam (e.g., the steam may be at a temperature between 60 to 200° C, and be saturated or superheated). The method may be implemented using the system described below.

[0083] In certain embodiments, systems and devices may be used for capturing CO2 from ambient air or other gas mixtures (e.g., flue gas, exhaust gas, natural gas, or other gases containing CO2, optionally mixed with ambient air). In some embodiments, the system includes a first device configured to introduce the ambient air or other gas mixture to the contactor, where the contactor includes those described herein. In some embodiments, the contactor is exposed to-18- 15083520.1WGS Docket No.: Z1034.70005WQ00the ambient air or other gas mixture for a period of time (e.g., minutes or hours). In certain embodiments, the contactor is a honeycomb monolith that has an open face area of between 0.3-0.95 of the total face area. The first device is configured to deliver the ambient air, for example, to the honeycomb monolith at a velocity of between 0.25-10 m / s. In some embodiments, the system includes a second device configured to heat the contactor containing adsorbed and / or absorbed CO2 after the desired amount of time to at least a first temperature (e.g., about 40 to 200° C, about 50 to 200° C, or about 60 to 200° C) to release the CO2. The second device of the system may operate to desorb CO2 by the contactor. The second device may include components to support temperature swing, pressure swing, steam swing, concentration swing, combinations thereof, or other dynamic processes to desorb the CO2. The steam swing process may include exposing the contactor to steam, where the temperature of the steam is about 60° C to 150° C and the pressure of the steam is about 0.2 bara to 5 bara. A third device is configured to collect the released CO2. The systems may be operated so that the contactor adsorbs (and / or absorbs) and desorbs the CO2 in an efficient and cost-effective manner.EXAMPLES

[0084] The following examples are merely illustrative of the presently disclosed subject matter and they should not be considered as limiting the scope of the subject matter in any way. Unless indicated otherwise, parts are parts by volume, temperature is in °C, and pressure is at or near atmospheric. Standard temperature and pressure are defined as 20 °C and 1 atmosphere.Schematic of a contactor with a sorbent-impregnated honeycomb monolith substrate

[0085] FIG. 1 shows one embodiment of a contactor with a honeycomb monolith substrate. FIG. 1 illustrates the primary geometrical features of an extruded honeycomb monolith scaffold (e.g., of cordierite), having straight, flowthrough channels surrounded on all sides by walls for low pressure drop gas flow. FIG. 1 schematically shows a washcoat of the sorbent retainer (e.g., porous alumina) applied to the walls of the scaffold. As shown in FIG. 1, a sorbent (e.g., PEI) is impregnated within the washcoat.Preparation of a powder substrate including dopants and polyethylenimine (PEI)

[0086] Mesoporous powder substrate (alumina) was modified with different dopants (salts of K, Na, Ca, Mg, Rb, Cs, La) using an incipient wetness impregnation technique. The incipient wetness impregnation technique leverages capillary action to draw precursor solution into a porous substrate. To this end, the pore volume of each substrate is determined first via N2-19- 15083520.1WGS Docket No.: Z1034.70005WQ00physisorption. For example, the pore volume of an alumina substrate is measured to be 0.87 mL / g. Set amounts of nitrate precursors (KNO3, NaNO3, Ca(NO3)2-4 H2O, Mg(NO3)2-4 H2O, RbNO3, CsNO3, and La(NO3)3-6 H2O, respectively) containing the desired metal element was then dissolved in a measured amount of water corresponding to the specific pore volume of each powder substrate. For example, if 2 grams of doped alumina substrate is to be prepared, a solution with a total volume of 1.72 mL (0.87*2) is obtained. For a 5wt% K-doped alumina substrate, 0.259 g of KNO3 would be dissolved in the 1.72 mL of water, yielding 0.1 g of potassium (KNO3 is 38.6% K by mass) in the solution. The dissolved metal salt solution was added dropwise to the powder substrate with vigorous mechanical agitation to ensure all solution was rapidly drawn into the pores via capillary action. After addition of the metal salt solution, the impregnated powders were dried for 2 h at 120 °C followed by calcination for >8h at 550 °C.

[0087] The calcined dopant-modified substrate was subsequently impregnated with PEI. The resulting composite contactors were of a powdery consistency.Preparation of a substrate with honeycomb channel structure with dopants and PEI

[0088] Alumina substrates with a honeycomb channel structure were modified with different dopants (salts of K, Ca, Mg) by immersing the substrate in an aqueous solution containing a set amount of dissolved nitrate precursor (KNO3, Ca(NOs)2-4 H2O, and Mg(NOs)2-4 H2O, respectively). The concentration of the solution was set to give the target amount of dopant in the volume corresponding to the pore volume of the substrate. When the pores were completely occupied with the dopant precursor solution, the solvent was removed. To remove the excess of solvent, the honeycomb channels were cleared out using an air knife and the substrate was then dried at 120 °C and calcined at 550 °C for lOh. The dopant-modified substrate was subsequently impregnated with PEI (e.g., to create an activated contactor).Characterization of the contactors and testing in CO2 adsorption processes

[0089] Chemical characterization was carried out to confirm the properties of dopant-modified contactors, including whether the sorbent was successfully incorporated into the pores of a dopant-modified porous substrate as detailed below.

[0090] N2 physisorption experiments were carried out on the contactors comprising dopant-modified porous substrates with and without the sorbent to characterize the porosity and surface area of the contactors. TGA burnoff experiments were carried out on the contactors comprising the sorbent and dopant-modified porous substrate to characterize the total quantity of organic-20- 15083520.1WGS Docket No.: Z1034.70005WQ00matters present in the contactors. Samples were heated under diluted air to 900° C and their mass loss tracked. Total organic content was taken as the mass loss over each temperature interval, after removing the contribution of CO2 and H2O lost at lower temperatures.

[0091] Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) was used to estimate the weight percentage of the dopants incorporated into the dopant-modified substrate. The EDS system consisted of a detector connected to a scanning electron microscope. EDS spectra were obtained at a 15 kV accelerating voltage and a working distance of 10 nm to maximize signal to the detector. The weight percentages of each element were computed from the spectra using analysis software.

[0092] Fractional coverage of the porous substrate by the dopants was estimated using the measured surface area of each unmodified substrate. The weight percent loading of the dopants was converted to surface area using the atomic radius of the dopant. Coverage was estimated by dividing the area occluded by the dopants by the total surface area of the porous substrate. This value exceeded unity for some higher weight loadings of the dopants, likely corresponding to multilayer formation of the dopants on the porous substrate.

[0093] Contactors comprising dopant-modified porous substrate and sorbent were tested for CO2 adsorption in a TGA to simulate the gas contacting step of a direct air capture process. The contactors were first treated in N2 at 100°C to desorb any bound H2O and CO2 before being equilibrated at 30° C under humidified N2. Then, the gas concentration was switched isothermally to contain humidified 400 ppm CO2 balanced by N2 and the mass change was recorded. To humidify the N2 and the 400 ppm CO2 balanced by N2 gases, the gas was saturated with water vapor at a dew point of 6-8 °C by sparging the gas stream in a water bath held at the corresponding temperature. Under these humid conditions, it is assumed that no additional water is adsorbed between switching from a humidified N2 stream to a humidified CO2 and N2 stream, and thus the mass gain of the material corresponds to the adsorption of CO2 and therefore may be used to measure the total quantity and rate of CO2 adsorption onto the materials.

[0094] Various contactors were characterized for CO2 adsorption using this method. The contactors were evaluated on two bases, i) CO2capacity, mmol of CO2adsorbed per mol of sorbent present, and ii) amine efficiency, mmol of CO2adsorbed per mol of nitrogen in PEI present in sample. The unit performance of CO2 capacity is useful to show bulk contactor-21- 15083520.1WGS Docket No.: Z1034.70005WQ00performance, and unit performance of amine efficiency is useful to evaluate the performance of the amine polymer itself and take into account changes to the bulk composition of the contactor. Table 1. Properties and performance of improved contactors created with PEI in doped alumina substrate.Amine Sorbent Dopant LoadingPore Volume Organic Efficiency Efficiency (wt% to aluminaDopant Salt (mL / g, before Loading (mol (mmol substrate before PEIPEI loading) (wt%) C02 / mol CO2 / g loading)N) sorbent) Mg 3.5 0.80 34.7 0.22 5.12 Ca 4.2 0.80 28.5 0.24 5.58 K 3.3 0.83 34.1 0.21 4.88 Na 2.1 0.83 28.6 0.24 5.58 None - 0.87 37.6 0.22 5.12 (unmodifiedAI2O3)

[0095] Table 1 provides the physical properties and CO2 adsorption properties of the contactors comprising PEI and the doped alumina substrate, as well as the properties of the contactors comprising PEI and alumina substrate without doping. The amine efficiency for doped substrate is relatively unchanged. The data from the table shows that there are no negative impacts to the amine efficiency of alumina doped substrate.Testing of oxidative stability

[0096] The oxidative stability of the contactors was evaluated by tracking the heat flow evolved from the contactors using a differential scanning calorimetry (DSC) tool during exposure to isothermal oxidative conditions. The contactors were first treated in inert gas at 100 °C to desorb any bound H2O and CO2 before being equilibrated at either 137.5 or 162.5 °C under inert gas for 60 minutes. The gas was then isothermally switched to a mixture of 17% O2 and 83% N2, or a mixture of 17% O2, 20% CO2, and 63% N2, and held until the reaction finished (gas concentrations given as mol%). This isothermal, oxidative environment was maintained for a specific amount of time to measure the heat flow and mass loss. To prevent any further oxidation, the sample was then cooled under N2 to room temperature. During these experiments,-22- 15083520.1WGS Docket No.: Z1034.70005WQ00for each oxidative condition, the DSC measures the incremental heat flux, which increases, levels out, and then decreases to zero. The oxidation was considered complete when the integrated heat flow over 10 min changed less than ±0.01% of the total integrated heat. To determine the extent of oxidation as a function of time, DSC data were converted from the base unit of mW / mg sorbent to W / g PEI using the PEI loading measured by TGA burnoff. DSC data were corrected for drift by applying an offset, determined by the heat flow value when the DSC curve approached a horizontal line. The total heat evolved was calculated by integrating heat flow over time. The extent of oxidation from DSC was calculated by dividing the integral heat flow curve by the total heat evolved. This method has been previously calibrated with the loss in amine efficiency as being a method of tracking the chemical reaction rate of oxidative degradation in-situ. Further details on this method and its validation are discussed in the following papers: Nezam et al, ACS Sustainable Chem. Eng., 2021, 9, 8477-8486, and Racicot et al, J. Phys. Chem. C, 2022, 126, 8807-8816, which is incorporated herein by reference.

[0097] FIG. 2 illustrates oxidation curves of alumina substrates (in powder form) comprising PEI, the testing of which was conducted in the presence of 17% O2 at 137.5 °C. FIG. 2 shows that Mg or Na doped alumina substrates do not greatly impact the oxidation rate of PEI when being compared with the undoped substrates, while the Ca or K doped alumina substrates slow the oxidation rate of PEI, with K doped substrate providing the greatest reduction in oxidation rate.

[0098] FIG. 3 illustrates the maximum rate of oxidation of alumina substrates (in powder form) as a function of the dopant surface coverage. The dashed horizontal line represents the observed oxidation rate at 137.5 °C of PEI in unmodified alumina substrates, and the solid vertical line corresponds to a fractional coverage of 1 (e.g., a single monolayer of dopants on the alumina surface). The figure shows that almost all dopants at any surface coverage reduce the maximum rate of oxidation as compared to undoped alumina. Additionally, the dopant efficacy appears to be higher with a high dopant coverage (e.g., greater than 1 monolayer), as shown in FIG. 3 with further reduced maximum rate of oxidation.Rate of oxidation of dopant-associated contactors as a function of metal electronegativity

[0099] FIG. 4 illustrates the maximum rate of oxidation of the contactors comprising PEI and doped alumina substrate as a function of Pauling electronegativity. FIG. 4 shows a correlation between decreasing electronegativity and a reduction in the maximum rate of oxidation of PEI.-23- 15083520.1WGS Docket No.: Z1034.70005WQ00FIG. 4 also shows that increasing surface coverage of the dopants further reduces the maximum rate of oxidation.Preparation of potassium-doped sorbent retainers

[0100] Potassium-doped sorbent retainer formulation (e.g., washcoat formulation) samples were made with a total solution weight of 250 g. 2.5 wt% boehmite (8.7 g) was added to 65.5 wt% DI H2O (164 mL) and stirred until complete dispersal solvation. A 32 wt% alumina formulation was then added in small increments to the aqueous solutions. The pH of the slurry was frequently checked and acetic acid was added to decrease the pH to 4.5, when the pH surpassed ca. 5.2. Once all sorbent retainer was added, a potassium salt (e.g., KNO3, KOH, or KCH3COO; 3.5 wt% K+) was added as a solid. Given the high basicity, the K-salt was added in small increments while measuring the pH. Once the pH increased past ca. 5.2, the pH was adjusted back down to 4.5 with acetic acid. This was repeated until all potassium (3.5 wt% K+) was added. Once all components were added to the formulation, an ‘initial’ pH was recorded. The formulation was then stirred for 2 h for equilibration. A ‘final’ pH value and viscosity were recorded. If the formulation pH was significantly higher than 4.5, small increments of acetic acid were added to lower the pH and the formulation was stirred for an addition 30-60 min to reequilibrate. An aliquot of the sorbent retainer formulation was dried at 120 °C overnight and then calcined at 550 °C / 4 h soak / 2 °C / min ramp.Preparation of an inactive contactor (not including sorbent) including doped sorbent retainer

[0101] The doped sorbent retainer formulation was poured over a scaffold (cordierite), ensuring that the sorbent retainer formulation volume was at least 0.5” over the top of the scaffold. The scaffold was submerged in the slurry for 5 mins after which extra slurry was removed. The scaffold was air knifed until no more sorbent retainer formulation was removed from the scaffold channels.* * *

[0102] Therefore, according to the above, some embodiments of the disclosure are directed to a CO2-capturing contactor. In some embodiments, the CO2-capturing contactor comprises a sorbent, a substrate, and one or more dopants associated with the substrate.

[0103] Additionally, or alternatively, in some embodiments, the one or more dopants include a metal oxide, metal hydroxide, metal nitrate, metal phosphate, metal hydride, metal nitrite, metal carbonate, metal phosphite, or combinations thereof.-24- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0104] Additionally, or alternatively, in some embodiments, the one or more dopants include a salt of metal that has a Pauling electronegativity of less than 2.2.

[0105] Additionally, or alternatively, in some embodiments, the one or more dopants include a salt of lithium, sodium, potassium, silicon, titanium, phosphorus, cesium, magnesium, calcium, strontium, barium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or combinations thereof.

[0106] Additionally, or alternatively, in some embodiments, the one or more dopants is a salt of potassium.

[0107] Additionally, or alternatively, in some embodiments, the one or more dopants are present within the substrate, on a surface of the substrate, or both.

[0108] Additionally, or alternatively, in some embodiments, the one or more dopants are incorporated into the substrate.

[0109] Additionally, or alternatively, in some embodiments, the substrate comprises a scaffold and a sorbent retainer coated onto a surface of the scaffold, and wherein the one or more dopants are included in the sorbent retainer.

[0110] Additionally, or alternatively, in some embodiments, the one or more dopants are included in a formulation that is extruded, molded, or printed to form the substrate.

[0111] Additionally, or alternatively, in some embodiments, the one or more dopants are associated with the substrate by contacting a surface of the substrate with a solution including the one or more dopants.

[0112] Additionally, or alternatively, in some embodiments, the sorbent is an amine.

[0113] Additionally, or alternatively, in some embodiments, the amine is physically impregnated into pores of the substrate.

[0114] Additionally, or alternatively, in some embodiments, the amine is physically impregnated onto a surface of the substrate.

[0115] Additionally, or alternatively, in some embodiments, the amine is covalently bonded to a surface of the substrate.

[0116] Additionally, or alternatively, in some embodiments, the sorbent is an amine polymer.-25- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0117] Additionally, or alternatively, in some embodiments, the amine polymer is a polymer or copolymer of polyethylenimine, polypropylenimine, polyallylamine, polyvinylamine, polyglycidylamine, polystyrene- divinylbenzene polymer functionalized with amine, or a mixture thereof.

[0118] Additionally, or alternatively, in some embodiments, the amine polymer is polyethylenimine.

[0119] Additionally, or alternatively, in some embodiments, the amine polymer may be branched, hyperbranched, dendritic, linear, or a mixture thereof.

[0120] Additionally, or alternatively, in some embodiments, the one or more dopants have a weight of not greater than 10% by weight of the substrate.

[0121] Additionally, or alternatively, in some embodiments, the one or more dopants have a weight of not less than 0.5% by weight of the substrate.

[0122] Additionally, or alternatively, in some embodiments, the one or more dopants have an amount of from 0.5 monolayers to 30 monolayers.

[0123] Additionally, or alternatively, in some embodiments, the substrate comprises one or more materials selected from ceramic, metal, metal oxide, plastic, cellulose, carbon, a zeolite, a metal organic framework (MOF), a porous organic framework (POF), a covenant organic framework (COF), a polymer of intrinsic microporosity (PIM), a polymer, a fibrous cellulose, fiberglass, boron-nitride fiber, or a combination thereof.

[0124] Additionally, or alternatively, in some embodiments, the substrate is one of a titania substrate, an alumina substrate, and a silica substrate.

[0125] Additionally, or alternatively, in some embodiments, the one or more dopants are incorporated into the substrate via incipient wetness impregnation.

[0126] Additionally, or alternatively, in some embodiments, the contactor has a structure selected from a honeycomb, a laminate sheet, a foam, fibers, a minimal surface solid, powder trays, pellets, or a combination thereof.

[0127] According to the above, some embodiments of the present disclosure are directed to a method of capturing CO2 from a gas. In some embodiments, the method comprises introducing the gas to a contactor, the contactor including a sorbent, a substrate, and one or more dopants associated with the substrate. In some embodiments, the method further comprises, after-26- 15083520.1WGS Docket No.: Z1034.70005WQ00introducing the gas to the contactor, heating the contactor to release captured CO2. In some embodiments, the method further comprises collecting the released CO2.

[0128] Additionally, or alternatively, in some embodiments, the one or more dopants comprise a metal salt or a metal oxide.

[0129] Additionally, or alternatively, in some embodiments, the one or more dopants are present within the substrate, on a surface of the substrate, or both.

[0130] Additionally, or alternatively, in some embodiments, the contactor has a structure selected from a honeycomb, a laminate sheet, a foam, fibers, a minimal surface solid, powder trays, pellets, or a combination thereof.

[0131] According to the above, some embodiments of the present disclosure are directed to a system for capturing CO2 from a gas. In some embodiments, the system comprises a first device configured to introduce the gas to a contactor, the contactor including a sorbent, a substrate, and one or more dopants associated with the substrate. In some embodiments, the system further comprises a second device configured to heat the contactor to release the captured CO2. In some embodiments, the system further comprises a third device configured to collect the released CO2.

[0132] Additionally, or alternatively, in some embodiments, the one or more dopants comprise a metal salt or a metal oxide.

[0133] Additionally, or alternatively, in some embodiments, the one or more dopants are present within the substrate, on a surface of the substrate, or both.

[0134] Additionally, or alternatively, in some embodiments, the contactor has a structure selected from a honeycomb, a laminate sheet, a foam, fibers, a minimal surface solid, powder trays, pellets, or a combination thereof.

[0135] According to the above, some embodiments of the present disclosure are directed to a method of making a contactor for CO2 capture. In some embodiments, the method comprises contacting a surface of a substrate or a formulation of the substrate with a solution of one or more dopants. In some embodiments, the method further comprises removing excess liquid of the solution. In some embodiments, the method further comprises incorporating a sorbent with the substrate.

[0136] Additionally, or alternatively, in some embodiments, the one or more dopants comprise a metal salt.-27- 15083520.1WGS Docket No.: Z1034.70005WQ00

[0137] Additionally, or alternatively, in some embodiments, the one or more dopants are present within the substrate, on a surface of the substrate, or both.

[0138] Additionally, or alternatively, in some embodiments, the method further comprises heating the substrate.

[0139] Additionally, or alternatively, in some embodiments, the substrate is heated before incorporating the sorbent with the substrate.

[0140] In addition to the various embodiments depicted and claimed, the disclosed subject matter is also directed to other embodiments having other combinations of the features disclosed and claimed herein. As such, the particular features presented herein can be combined with each other in other manners within the scope of the disclosed subject matter such that the disclosed subject matter includes any suitable combination of the features disclosed herein. The foregoing description of specific embodiments of the disclosed subject matter has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosed subject matter to those embodiments disclosed.

[0141] The terms used in this specification generally have their ordinary meanings in the art, within the context of this subject matter and in the specific context where each term is used.

[0142] As used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a compound” includes mixtures of compounds.

[0143] The term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can mean within three or more than three standard deviations, per the practice in the art. Alternatively, “about” can mean a range of up to 20%, preferably up to 10%, more preferably up to 5%, and more preferably still up to 1% of a given value. Also, particularly with respect to systems or processes, the term can mean within an order of magnitude, preferably within five-fold, and more preferably within two-fold, of a value.

[0144] Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is encompassed within the disclosure. The upper and lower limits of these smaller ranges-28- 15083520.1WGS Docket No.: Z1034.70005WQ00may independently be included in the smaller ranges and are also encompassed within the disclosure, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the disclosure.

[0145] Terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present disclosure will be limited only by the appended claims. Unless otherwise indicated, the present disclosure is not limited to particular materials, reagents, reaction materials, manufacturing processes, or the like, as such can vary. Steps of methods disclosed in the present disclosure can be executed in different sequences where it is logically possible.-29- 15083520.1

Claims

WGS Docket No.: Z1034.70005WQ00CLAIMSWhat is claimed is:

1. A C02-capturing contactor, comprising a sorbent, a substrate, and one or more dopants associated with the substrate.

2. The CO2-capturing contactor of claim 1, wherein the one or more dopants include a metal oxide, metal hydroxide, metal nitrate, metal phosphate, metal hydride, metal nitrite, metal phosphite, metal carbonate, or combinations thereof.

3. The CO2-capturing contactor of claim 1, wherein the one or more dopants include a salt of metal that has a Pauling electronegativity of less than 2.2.

4. The CO2-capturing contactor of claim 1, wherein the one or more dopants include a salt of lithium, sodium, potassium, silicon, titanium, cesium, magnesium, calcium, strontium, barium, yttrium, lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or combinations thereof.

5. The CO2-capturing contactor of claim 1, wherein the one or more dopants is a salt of potassium.

6. The CO2-capturing contactor of claim 1, wherein the one or more dopants are present within the substrate, on a surface of the substrate, or both.

7. The CO2-capturing contactor of claim 1, wherein the one or more dopants are incorporated into the substrate.

8. The CO2-capturing contactor of claim 7, wherein the substrate comprises a scaffold and a sorbent retainer coated onto a surface of the scaffold, and wherein the one or more dopants are included in the sorbent retainer.WGS Docket No.: Z1034.70005WQ009. The C02-capturing contactor of claim 7, wherein the one or more dopants are included in a formulation that is extruded, molded, or printed to form the substrate.

10. The CO2-capturing contactor of claim 1, wherein the one or more dopants are associated with the substrate by contacting a surface of the substrate with a solution including the one or more dopants.

11. The CO2-capturing contactor of claim 1, wherein the sorbent is an amine.

12. The CO2-capturing contactor of claim 11, wherein the amine is physically impregnated into pores of the substrate.

13. The CO2-capturing contactor of claim 11, wherein the amine is physically impregnated onto a surface of the substrate.

14. The CO2-capturing contactor of claim 11, wherein the amine is covalently bonded to a surface of the substrate.

15. The CO2-capturing contactor of claim 1, wherein the sorbent is an amine polymer.

16. The CO2-capturing contactor of claim 15, wherein the amine polymer is a polymer or copolymer of polyethylenimine, polypropylenimine, polyallylamine, polyvinylamine, polyglycidylamine, polystyrene- divinylbenzene polymer functionalized with amine, or a mixture thereof.

17. The CO2-capturing contactor of claim 15, wherein the amine polymer is polyethylenimine.

18. The CO2-capturing contactor of claim 15, wherein the amine polymer may be branched, hyperbranched, dendritic, linear, or a mixture thereof.WGS Docket No.: Z1034.70005WQ0019. The C02-capturing contactor of claim 1, wherein the one or more dopants have a weight of not greater than 10% by weight of the substrate.

20. The CO2-capturing contactor of claim 1, wherein the one or more dopants have a weight of not less than 0.5% by weight of the substrate.

21. The CO2-capturing contactor of claim 1, wherein the one or more dopants have an amount of from 0.5 monolayers to 30 monolayers.

22. The CO2-capturing contactor of claim 1, wherein the substrate comprises one or more materials selected from ceramic, metal, metal oxide, plastic, cellulose, carbon, a zeolite, a metal organic framework (MOF), a porous organic framework (POF), a covenant organic framework (COF), a polymer of intrinsic microporosity (PIM), a polymer, a fibrous cellulose, fiberglass, boron-nitride fiber, or a combination thereof.

23. The CO2-capturing contactor of claim 1, wherein the substrate is one of a titania substrate, an alumina substrate, and a silica substrate.

24. The CO2-capturing contactor of claim 1, wherein the one or more dopants are incorporated into the substrate via incipient wetness impregnation.

25. The CO2-capturing contactor of claim 1, wherein the contactor has a structure selected from a honeycomb, a laminate sheet, a foam, fibers, a minimal surface solid, powder trays, pellets, or a combination thereof.

26. A method for capturing CO2 from a gas, comprising:introducing the gas to a contactor, the contactor including a sorbent, a substrate, and one or more dopants associated with the substrate;after introducing the gas to the contactor, heating the contactor to release captured CO2; andcollecting the released CO2.WGS Docket No.: Z1034.70005WQ0027. The method of claim 26, wherein the one or more dopants comprise a metal salt or a metal oxide.

28. The method of claim 26, wherein the one or more dopants are present within the substrate, on a surface of the substrate, or both.

29. The method of claim 26, wherein the contactor has a structure selected from a honeycomb, a laminate sheet, a foam, fibers, a minimal surface solid, powder trays, pellets, or a combination thereof.

30. A system for capturing CO2 from a gas, comprising:a first device configured to introduce the gas to a contactor, the contactor including a sorbent, a substrate, and one or more dopants associated with the substrate;a second device configured to heat the contactor to release captured CO2; and a third device configured to collect the released CO2.

31. The system of claim 30, wherein the one or more dopants comprise a metal salt.

32. The system of claim 30, wherein the one or more dopants are present within the substrate, on a surface of the substrate, or both.

33. The system of claim 30, wherein the contactor has a structure selected from a honeycomb, a laminate sheet, a foam, fibers, a minimal surface solid, powder trays, pellets, or a combination thereof.

34. A method of making a contactor for CO2 capture, comprising:contacting a surface of a substrate or a formulation of the substrate with a solution of one or more dopants;removing excess liquid of the solution; andincorporating a sorbent with the substrate.

35. The method of claim 34, wherein the one or more dopants comprise a metal salt or aWGS Docket No.: Z1034.70005WQ00metal oxide.

36. The method of claim 34, wherein the one or more dopants are present within the substrate, on a surface of the substrate, or both.

37. The method of claim 34, further comprising heating the substrate.

38. The method of claim 37, wherein the substrate is heated before incorporating the sorbent with the substrate.

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