Glycidyl ether modified amine adsorbents, systems including adsorbents, and methods of using adsorbents

Abstract

The present disclosure provides adsorbents and contactors, methods of capturing CO2 using the adsorbents and contactors, structures including the adsorbents, and systems and devices for capturing CO2 using the adsorbents and contactors. In one aspect, the disclosure provides an adsorbent comprising a CO2-philic phase and a carrier. In one aspect, the disclosure provides adsorbents and contactors that include a CO2-philic phase and a carrier, where the CO2-philic phase includes a modified amine polymer that is a reaction product of an amine and a glycidyl ether.

Description

[0001] Priority Claim of Related Applications

[0002] This application claims priority to co-pending U.S. Provisional Application No. 63 / 431,512, filed on December 9, 2022, entitled "SORBENTS, SYSTEMS INCLUDING SORBENTS, AND METHODS USING THE SORBENTS", which is hereby incorporated by reference in its entirety.

[0003] This application also claims priority to co-pending patent application PCT / US2023 / 066670, filed on May 5, 2023, entitled "SUBSTITUTED EPOXIDE MODIFIED SORBENTS, SYSTEMS INCLUDING SORBENTS, AND METHODS USING THE SORBENTS", where PCT / US2023 / 066670 claims priority to U.S. Provisional Application No. 63 / 364,308, filed on May 6, 2022, entitled "SORBENTS, SYSTEMS INCLUDING SORBENTS, AND METHODS USING THE SORBENTS", and PCT / US2023 / 066670 also claims priority to co-pending U.S. Provisional Application No. 63 / 431,512, filed on December 9, 2022, entitled "SORBENTS, SYSTEMS INCLUDING SORBENTS, AND METHODS USING THE SORBENTS", each of which is hereby incorporated by reference in its entirety. Background Art

[0004] Greenhouse gases trap heat in the atmosphere, and carbon dioxide (CO2) is one of the major greenhouse gases. Carbon dioxide is emitted through human-related activities such as transportation, electricity, industry, and agriculture. In particular, burning fossil fuels, solid waste, and trees, as well as manufacturing cement and other materials, all generate CO2 emissions. One way to reduce the amount of CO2 in the atmosphere is to use materials that have an affinity for CO2 to capture CO2. There is a need for materials that can effectively capture CO2. Summary of the Invention

[0005] The present disclosure provides sorbents and contactors, methods of using sorbents and contactors to capture CO2, structures including sorbents, and systems and devices for using sorbents and contactors to capture CO2.

[0006] In one aspect, the present disclosure provides an adsorbent comprising: a CO2-philic phase and a support, wherein the CO2-philic phase comprises a reaction product of an amine and a glycidyl ether. In one aspect, the glycidyl ether may be selected from glycidol, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, hexyl glycidyl ether, octyl glycidyl ether, isopropyl glycidyl ether, tert-butyl glycidyl ether, (R)-phenyl glycidyl ether, allyl glycidyl ether, 1,4-bis(glycidyloxy)benzene, or a mixture thereof. In one aspect, the CO2-philic phase comprises at least one structure selected from the following structures, wherein R x is a substituted group:

[0007]

[0008] wherein R1 is selected from a hydrogen atom, a halogen, a straight-chain or branched-chain alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a benzyl group, a phenol group, or a heteroaryl group, etc., and each R’ is independently selected from a hydrogen atom, an alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a benzyl group, a phenyl group, a phenol group, an amino group, or a heteroaryl group.

[0009] In one aspect, the present disclosure provides a contactor comprising a structure and the adsorbent as described above herein.

[0010] In one aspect, the present disclosure provides a system for capturing CO2 from a gas, optionally the gas is ambient air, the system comprising: a first device configured to introduce the gas into the adsorbent or contactor as described above herein to bind CO2 to the adsorbent; a second device configured to heat the adsorbent containing the bound CO2 to at least a first temperature to release CO2; and a third device configured to collect the released CO2.

[0011] In one aspect, the present disclosure provides a method for capturing CO2 from a gas, optionally the gas is ambient air, the method comprising: introducing ambient air into the adsorbent as described above herein to bind CO2 to the adsorbent; heating the adsorbent to at least a first temperature to controllably release CO2, and collecting CO2 in a CO2 collection device.

[0012] In one aspect, the present disclosure provides a system for implementing the method as described above herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Other aspects of the present disclosure will be more readily understood when reading the detailed description of the different embodiments of the present disclosure described below in conjunction with the accompanying drawings.

[0014] Figure 1A A schematic diagram showing how the amine moiety binds CO2 into a carbamate. Figure 1BSchematic diagram of an adsorbent system composed of a support and a CO₂-philic phase. The support and the CO₂-philic phase together constitute the adsorbent.

[0015] Figure 2 Schematic diagram of a honeycomb monolithic contactor composed of a substrate and an adsorbent coating.

[0016] Figure 3 Shows the evaluation of glycidyl ethers as PEI modifiers.

[0017] Figure 4 Shows the synthetic routes of glycidyl hexyl ether (GHE) and glycidyl octyl ether (GOE).

[0018] Figure 5 Shows the general route of the reaction of PEI with glycidyl ethers.

[0019] Figure 6 Shows the 1 ¹H NMR spectra of PEI (upper figure) and the reaction product of PEI with glycidyl octyl ether (0.5 mol glycidyl ether / mol primary amine in PEI) (lower figure).

[0020] Figure 7A Shows the mass loss curves of mesoporous alumina, unmodified PEI in mesoporous alumina, and the reaction product of PEI and GOE in mesoporous alumina during heating from room temperature to 900 °C under exposure to diluted air; Figure 7B Shows the heat flow (DSC) curves of mesoporous alumina, unmodified PEI in mesoporous alumina, and the reaction product of PEI and GOE in mesoporous alumina during heating from room temperature to 900 °C under exposure to diluted air.

[0021] Figure 8 Shows the instantaneous temperature and mass change curves of the TGA CO₂ adsorption experiments of the improved adsorbents (containing the reaction products of PEI with glycidyl butyl ether (GBE), PEI with glycidyl hexyl ether (GHE), and PEI with glycidyl octyl ether (GOE), all 0.5 mol glycidyl ether / mol primary amine in PEI) at 400 ppm CO₂ (DAC conditions). All adsorbents are loaded in mesoporous alumina. The adsorbent data using unmodified PEI is used as a control, and the results are expressed as amine efficiency (mmol CO₂ / mmol N).

[0022] Figures 9A to 9D Shows the degree of oxidation of PEI over time, which is determined by differential scanning calorimetry (solid line, DSC) as described herein and discussed in the reference publications, and by Figure 9A ( Figure 9B ) 5%, (Figure 9C ) Determined by the loss of amine efficiency (data points, AE) at 30% O2 concentration; Figure 9D ) Degree of oxidation of different PEI pore fillers. Figures 9A to 9D From Nezam et al., ACS Sustainable Chem. Eng., 2021, 9, 8477 - 8486.

[0023] Figure 10 Shows the transient oxidation curves of PEI and modified CO2 adsorbents (containing the reaction products of PEI and glycidyl ethers) at 17% O2, balance N2, and 137.5 °C. All adsorbents are loaded in mesoporous alumina.

[0024] Figure 11 Shows the transient temperature and mass change curves after oxidation treatment at 120 °C and 17% O2 for 3 hours. The data are from TGA CO2 adsorption experiments using modified adsorbents (containing the reaction products of PEI and glycidyl octyl ether (GOE), PEI and glycidyl hexyl ether (GHE), PEI and glycidyl butyl ether (GBE), all 0.5 moles of glycidyl ether per mole of primary amine in PEI) at 400 ppm CO2 (DAC conditions). All adsorbents are loaded in mesoporous alumina. The data of the adsorbent using unmodified PEI are used as a control, and the results are expressed as amine efficiency (mmol CO2 / mmol N).

[0025] Figure 12 Shows the transient temperature and mass change curves after oxidation treatment at 137 °C, 21% O2 humidified with 50% relative humidity for 3 hours. The data are from TGA CO2 adsorption experiments using modified adsorbents (containing the reaction products of PEI and glycidyl octyl ether (GOE), PEI and glycidyl hexyl ether (GHE), PEI and glycidyl butyl ether (GBE), all 0.5 moles of glycidyl ether per mole of primary amine in PEI) at 400 ppm CO2 (DAC conditions). All adsorbents are loaded in mesoporous alumina. The data of the adsorbent using unmodified PEI are used as a control, and the results are expressed as amine efficiency (mmol CO2 / mmol N).

[0026] Figure 13 Shows the structure of glycidyl ethers that can react with amines to form an improved CO2 - philic phase. Detailed Description of the Invention

[0027] Embodiments of the present disclosure provide adsorbents (also referred to herein as "an adsorbent" or "adsorbents"), contactors, methods of using the adsorbents and contactors to capture CO2, structures comprising the adsorbents, and systems and devices for using the adsorbents and contactors to capture CO2. In one aspect, the present disclosure provides an adsorbent comprising a CO2-philic phase (e.g., a modified amine polymer that is a reaction product of an amine and a glycidyl ether) and a support. The methods, systems, adsorbents, and contactors of the present disclosure may be superior to current technologies because they are relatively more robust and reduce the cost of capturing CO2, particularly from ambient air. In one aspect, the present disclosure provides an adsorbent having an improved CO2-philic phase (e.g., a modified amine polymer that is a reaction product of an amine and a glycidyl ether), the improved CO2-philic phase having enhanced antioxidant properties.

[0028] Before describing the present disclosure in more detail, it is to be understood that the present disclosure is not limited to the particular embodiments described, as such may, of course, vary. It should also be understood that the 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 defined only by the appended claims.

[0029] Where a numerical range is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit, between the upper and lower limits of that range, and any other stated value or intervening value in that stated range, is encompassed within the present disclosure. The upper and lower limits of these smaller ranges may independently be included in the smaller ranges and are also encompassed within the present disclosure, subject to any specifically excluded limitation in the stated range. When the stated range includes one or both of the limit values, ranges excluding either or both of those included limit values are also included in the present disclosure.

[0030] All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs, unless otherwise defined. Although any methods and materials similar or equivalent to those described herein can also be used in the practice or testing of the present disclosure, the preferred methods and materials are described herein.

[0031] As will be apparent to those of ordinary skill in the art upon reading the present disclosure, each of the individual embodiments described and illustrated herein has discrete components and features that can be readily separated from or combined with the features of any of the other several embodiments without departing from the scope or spirit of the present disclosure. Any of the described methods can be performed in the order of events described or in any other order that is logically possible.

[0032] Unless otherwise indicated, embodiments of the present disclosure will employ techniques in chemistry, materials science, mechanical engineering, and the like, all of which are within the skill of the art.

[0033] The following examples are put forward to provide a complete disclosure and description to those of ordinary skill in the art on how to implement the methods disclosed and claimed herein and use the detectors disclosed and claimed herein. Efforts have been made to ensure the accuracy of numbers (e.g., amounts, temperatures, etc.), but some errors and deviations should be taken into account. Unless otherwise indicated, parts are by volume, temperature is in °C, and pressure is at or near atmospheric pressure. Standard temperature and pressure are defined as 20 °C and 1 atmosphere.

[0034] Before describing the embodiments of the present disclosure in detail, it should be understood that unless otherwise indicated, the present disclosure is not limited to specific materials, reagents, reaction materials, manufacturing processes, etc., as they can vary. It should also be understood that the terms used herein are only for the purpose of describing specific embodiments and not for limiting. In the present disclosure, where logically possible, different step sequences can also be performed.

[0035] It must be noted that, 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 a plurality of compounds. In this specification and the subsequent claims, many terms will be mentioned, and unless there is an obvious contrary intention, these terms will be defined to have the following meanings.

[0036] Discussion

[0037] The present disclosure provides adsorbents (also referred to herein as "an adsorbent" or "adsorbents"), contactors, methods for using the adsorbents and contactors to capture CO2, structures including the adsorbents, and systems and devices for using the adsorbents and contactors to capture CO2. In one aspect, the present disclosure provides an adsorbent that includes a CO2-philic phase and a support. The present disclosure relates to various types of adsorbents and structures that will be described hereinafter and herein.

[0038] In one aspect, the present disclosure provides an adsorbent and a contactor that include a CO₂-philic phase and a support, wherein the CO₂-philic phase includes a modified amine polymer that is a reaction product of an amine and a glycidyl ether, and the reaction product is also described herein. In one aspect, the modified amine polymer maintains a high CO₂ capacity relative to an unmodified amine polymer. In one aspect, compared to an adsorbent produced with an unmodified amine polymer, an adsorbent having a modified amine polymer loses less of its ability to capture CO₂ after exposure to oxidation, resulting in an improved CO₂-philic phase with a longer commercial lifespan relative to a CO₂-philic phase that has not been reacted with a glycidyl ether.

[0039] In one aspect, compared to similar modified amine polymers modified by reaction with an epoxide or a non-oxygen-containing group, a modified amine polymer modified by reaction with a glycidyl ether will exhibit stronger hydrophilicity and higher polarity. By regulating the hydrophilicity and polarity of the CO₂-philic phase, the stability, production performance, and energy consumption requirements of the adsorbent during the CO₂ adsorption process can be balanced. Different CO₂ adsorption processes may require adsorbents with different hydrophilicities and polarities to achieve optimal results.

[0040] A structured support, also referred to as a shaped support or a structure, refers to a support that has been shaped into a structure that is solid under standard conditions. The support can also be unstructured and have a powdery consistency under standard conditions. When referring to a support without mention of structure, shaping, being shaped, or structured, it can refer to either a structured or an unstructured support.

[0041] A structured support can take the form of a homogeneous solid (i.e., mainly composed of the support but also containing components that allow it to maintain a stable body under standard conditions) or as a coating on a substrate, where the substrate has a different composition from the coating and provides mechanical stability to the coating.

[0042] In the process of removing CO₂ from a gas stream such as ambient air, it is useful to utilize a structured support having a CO₂-philic phase as a contactor. The contactor provides a geometry for the CO₂-philic phase such that considerations such as pressure drop, production rate, and / or mass transfer rate can be optimized. An active support or an active structured support refers to a support or a structured support that contains a CO₂-philic phase at a specific loading within the volume of its mesopores and / or on its surface. The specific loading of the CO₂-philic phase is determined by the mesopore volume of the support or structured support itself and is expressed as the percentage of the mesopore volume occupied by the CO₂-philic phase. The specific loading level applied to the support needs to be precisely controlled, as it may vary when the active support, structured support, or contactor (i.e., the adsorbent) is different, or when the active support, structured support, or contactor (i.e., the adsorbent) is deployed in a specific climate or environment.

[0043] The pro-CO2 phase contains a CO2-binding molecule. The CO2-binding molecule contains a CO2-binding moiety. In one aspect, when the pro-CO2 phase is loaded onto a porous support material (such as to form an efficient CO2 adsorbent), the CO2-binding molecule can be an amine or an amine polymer, such as the modified amines described herein. The amine or amine polymer (e.g., for forming the modified amine and / or the modified amine itself) can contain primary amines, secondary amines, tertiary amines, or a mixture of any combination of primary, secondary, and tertiary amines. The amine polymer can be branched, hyperbranched, dendritic, or linear. The CO2-binding moiety is the amine moiety on the amine molecule or polymer (e.g., the modified amine). The amine moiety can interact with CO2 to form a carbamate, carbonate, or bicarbonate species. Figure 1A A schematic diagram showing how the amine moiety binds CO2 into a carbamate is shown.

[0044] A primary amine is defined as having the chemical structure -NH2R 1 , where R 1 is an alkyl group, such as CH2 or CH3. A secondary amine is defined as having the chemical structure -NHR 1 R 2 , where R 1 and R 2 are independently selected from alkyl groups, such as CH2 or CH3. A tertiary amine is defined as having the chemical structure -NR 1 R 2 R 3 , where R 1 , R 2 and R 3 are independently selected from alkyl groups, such as CH2 or CH3.

[0045] A linear amine polymer can be defined as containing only primary amines, secondary amines, or both primary and secondary amines. The ratio of secondary amines to primary amines can be from about 0.5 to 10,000. In one aspect, the molecular weight of the linear amine polymer can be from about 100 g / mol to 100,000 g / mol, from about 200 to 30,000 g / mol, or from about 600 g / mol to 5,000 g / mol.

[0046] Branched amine polymers can be defined as containing any number of primary, secondary, and tertiary amines, which do not overlap with linear amine polymers or dendrimeric amine polymers. The ratio of primary, secondary, and tertiary amines can be from about 10:80:10 to 60:10:30, from about 60:30:10 to 30:50:20, or from about 45:45:10 to 35:45:20. As will be understood by those skilled in the art, the chemical structure of branched amine polymers can vary widely and can be very complex. In one aspect, the molecular weight of the branched amine polymer can be from about 100 g / mol to 100,000 g / mol, from about 200 g / mol to 30,000 g / mol, or from about 600 g / mol to 5,000 g / mol.

[0047] Dendrimeric amine polymers can be defined as containing only primary and tertiary amines, wherein the repeating unit groups are arranged in a manner that must be symmetric in at least one plane passing through the molecular center (core), wherein each polymer branch is terminated by a primary amine, and wherein each branching point is a tertiary amine. The core or central bond is the same as that of the branched amine (e.g., ethyleneimine core and ethyleneimine branches, propyleneimine core and propyleneimine branches). The ratio of primary amines to tertiary amines can be from about 1 to 3. In one aspect, the molecular weight of the dendrimeric amine polymer can be from about 100 g / mol to 100,000 g / mol, from about 200 g / mol to 30,000 g / mol, or from about 280 to 3,000.

[0048] Hyperbranched amine polymers can be defined as having a chemical structure similar to that of dendrimeric amine polymers, but containing defects in the form of secondary amines (e.g., linear subparts present in the branched polymer), in such a way as to provide a random chemical structure rather than a symmetric chemical structure. Hyperbranched amine polymers do not overlap with branched amine polymers or dendrimeric polymers. In the hyperbranched chemical structure, the ratio of primary, secondary, and tertiary amines can be from about 65:5:30 to 30:10:60. In one aspect, the molecular weight of the hyperbranched amine polymer can be from about 100 g / mol to 100,000 g / mol, from about 200 g / mol to 30,000 g / mol, or from about 600 g / mol to 10,000 g / mol.

[0049] In one aspect, linear, hyperbranched, and branched amine polymers have secondary amines, while dendrimeric amines do not, which may be advantageous because secondary amines bind strongly to CO2.

[0050] In one aspect, the amine polymer can be polyethyleneimine, polypropyleneimine, polyallylamine, polyvinylamine, polyglycidylamine, a polystyrene-divinylbenzene polymer partially functionalized with an amine such as alkylbenzylamine, or other amine polymers, each of which can be branched, hyperbranched, dendrimeric, or linear.

[0051] In one embodiment, the size (e.g., length, molecular weight), amount (e.g., number of different amine polymers), and / or type of the amine polymer can be selected based on the desired properties of the porous support (e.g., CO2 absorption, regeneration performance, oxidation stability, loading, etc.).

[0052] In one aspect, the modified amine polymer can include a primary amine, a secondary amine, a tertiary amine, or a mixture of any combination of primary, secondary, and tertiary amines, each of which is defined as above. The modified amine polymer can be branched, hyperbranched, dendritic, or linear, each of which is defined as above.

[0053] In one aspect, the glycidyl ether reacted with the amine can include one or more of the following: glycidol, glycidyl methyl ether, glycidyl ethyl ether, glycidyl butyl ether, glycidyl hexyl ether, glycidyl octyl ether, glycidyl isopropyl ether, tert-butyl glycidyl ether, (R)-glycidyl phenyl ether, allyl glycidyl ether, or 1,4-bis(glycidyloxy)benzene.

[0054] In one aspect, prior to the reaction, the modified amine polymer can be a primary amine or a secondary amine to form a secondary amine or a tertiary amine. Exemplary structures are shown below, where R x is a substituted group:

[0055]

[0056] In one aspect, R1 can be a hydrogen atom, a halogen, a straight-chain or branched-chain alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a benzyl group, a phenol group, a heteroaryl group, etc., and combinations thereof. In one aspect, R1 can be a straight-chain or branched-chain alkyl group or a haloalkyl group. In one aspect, R1 can be an aryl group, a benzyl group, a phenol group, or a heteroaryl group. In one aspect, each R' can independently be selected from a hydrogen atom, an alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a benzyl group, a phenyl group, a phenol group, an amine group (e.g., alkyleneimine (C2 to C8) such as ethyleneimine and propyleneimine), a heteroaryl group, etc., and combinations thereof. In one aspect, each R' can independently be selected from an alkyl group or a haloalkyl group. In one aspect, each R' can independently be selected from an aryl group, a benzyl group, a phenyl group, a phenol group, or a heteroaryl group. In one aspect, each R' can independently be selected from an amine group (e.g., alkyleneimine (C2 to C8) such as ethyleneimine and propyleneimine).

[0057] In one aspect, the modification of the amine polymer by reaction with the glycidyl ether reduces the total number of primary amines in the modified amine polymer system.

[0058] In one aspect, the modified amine polymer can be a modified polyethyleneimine, a modified polypropyleneimine, a modified polyallylamine, a modified polyvinylamine, a modified polyglycidylamine, a modified polystyrene-divinylbenzene polymer partially functionalized with an amine such as an alkylbenzylamine, or other modified amine polymers, where each modified amine polymer can be branched, hyperbranched, dendritic, or linear.

[0059] In one aspect, the fraction of the modified amine as described herein can be from about 0.001 to 1, or from about 0.01 to 1, or from about 0.1 to 1, or from about 0.5 to 1 of the total primary and secondary amines in the amine polymer, or the fraction can be from about 0.01 to 0.5 of the amines in the amine polymer, where a fraction of 1 means all are primary and secondary amines.

[0060] While not intending to be bound by theory, the CO2-philic phase modified by reaction with a glycidyl ether allows for the reasonable introduction of substituents on the amine polymer to adjust the properties of the CO2-philic phase. For example, large substituents such as phenyl or substituted phenyl can be used to sterically block oxygen attack during the oxidation reaction. In addition, the substituent groups can also be used to chemically stabilize the amine polymer against oxidation. Chemical stabilization can be achieved by introducing electron-donating or electron-withdrawing substituents on the amine polymer. The amount, type, and combination of the modifiers can be adjusted and varied to obtain the desired properties of the CO2-philic phase. Adjusting the CO2-philic phase can result in one or a combination of the following improvements in the CO2 adsorbent: increased lifetime due to a reduced oxidation degradation rate, increased amine efficiency of the adsorbent, increased CO2 swing capacity of the adsorbent during the adsorption / desorption process, increased equilibrium capacity of the adsorbent.

[0061] In one aspect, it may be advantageous to improve the stability of the CO2-philic phase under the process conditions associated with the use of the adsorbent in the CO2 separation process, particularly during adsorbent regeneration (the process cycle of raising the adsorbent temperature to remove the bound CO2). It is also advantageous to improve the stability of the CO2-philic phase under the conditions associated with adsorbent storage when the adsorbent is not in use in a process or equipment. An adsorbent having a CO2-philic phase is valuable, which has improved stability for process conditions including adsorbent regeneration, storage, or both process conditions including adsorbent regeneration and storage.

[0062] Evaluating the oxidation stability of materials in an environment containing oxygen and CO2 is useful because during the regeneration process, at elevated temperatures, in addition to oxygen, the desorbed CO2 is also present at different concentrations and can affect the stability of the materials. Additionally, evaluating the oxidation stability of materials containing only oxygen (air) is an effective method for assessing the shelf life of materials when stored under environmental conditions.

[0063] As described above, the CO₂-philic phase (e.g., CO₂-binding molecules) can be homogeneous or heterogeneous. When the CO₂-philic phase is heterogeneous, the CO₂-binding molecules can exist in a variety of ways. For example, the CO₂-binding molecules can be applied or incorporated to form a layer of the CO₂-philic phase on a support, such as on the pore surface of the support. On the other hand, when used independently or in combination with other aspects such as those described above, the CO₂-binding molecules can be used to form part or all of the support, where the CO₂-philic phase functions as described herein. Various combinations are contemplated and are part of the present disclosure. Other ways of uniformly and / or non-uniformly applying, using, or incorporating the CO₂-philic phase are described herein and below.

[0064] As described herein, the adsorbent comprises a CO₂-philic phase (e.g., CO₂-binding molecules) and a support. The support comprises a surface (e.g., a surface that can be exposed to a gas containing CO₂ and / or can interact with the CO₂-philic phase during normal use). The surface can be the surface of a pore and / or other surface with which the CO₂-philic phase contacts or interacts.

[0065] In one aspect, the CO₂-philic phase (e.g., CO₂-binding molecules) can be disposed on and / or within the support to form an adsorbent. The CO₂-philic phase can be disposed on the surface of the support, and / or within the pores of the support, and / or on the outer surface of the support, or any combination thereof. In one aspect, the CO₂-philic phase can be a coating on the surface of a porous material, a monolayer on the surface of a porous material, a self-assembled monolayer on the surface of a porous material, a bulk phase within the pores of a porous material, a coating on the outer surface of a porous material, etc.

[0066] In one aspect, the support can be made of one or more types of materials, such as ceramics, metals, metal oxides, plastics, cellulose, carbon, zeolites, metal-organic frameworks (MOFs), porous organic frameworks (POFs), covalent organic frameworks (COFs), polymers of intrinsic microporosity (PIMs), polymers, fibrous cellulose, fiberglass, boron nitride fibers, etc. On the other hand, the support can be made of a material that also includes the CO₂-philic phase.

[0067] The metal oxide support can be selected from cordierite, alumina (such as γ-alumina, θ-alumina, δ-alumina), cordierite-α-alumina, silica, aluminosilicate, zirconia, germanium oxide, magnesia, titanium dioxide, hafnium oxide, silicon nitride, zircon mullite, spodumene, alumina-silica magnesia, zirconium silicate, sillimanite, magnesium silicate, zircon, petalite, and combinations thereof. In the case where the oxide contains a formal charge, the charge can be balanced by a suitable counterion, 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, etc. The metal oxide can contain dopants, such as zirconium, iron, tin, silicon, titanium, and combinations thereof. It is well known that metal oxides can contain acidic, basic, and neutral sites on their surface, and dopants can change the number and strength of acidic and basic sites on the surface.

[0068] In one aspect, the polymer support can be polyolefin, polyester, polyurethane, polycarbonate, polyetheretherketone, polyphenylene ether, polyethersulfone, melamine, polyamide, polyvinylbenzene, polystyrene-divinylbenzene, polyurethane, polyacrylate, polystyrene, polyacrylonitrile, polyimide, polyfurfural alcohol, phenol furfural, melamine formaldehyde, resorcinol formaldehyde, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurate, polyacrylamide, various epoxy resins, agar, and agarose, or combinations thereof.

[0069] The support can be porous (e.g., macroporous, mesoporous, microporous, or mixtures thereof (e.g., where the macroporous surface can include mesopores and / or micropores within one or more macropores, where the mesoporous surface can include micropores, etc.)). In one aspect, the porous structure is mesoporous. The pores can extend through the porous structure or porous layer, or only extend to a certain depth. The macropores of the porous structure can have pores with 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. The mesopores of the porous structure can have pores with 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. The micropores of the porous structure can have pores with a diameter of about 0.5 nm to 5 nm, a length of about 0.5 nm to 1000 nm, and a volume of about 0.1 - 1 cc / g.

[0070] The support can be porous, and the porosity is 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%. In some embodiments, the surface area of the support can be about 1 m 2 / g or greater, about 10 m 2 / g or greater, about 100 m 2 / g or greater, about 150 m 2 / g or greater, about 200 m 2 / g or greater, or about 250 m 2 / g or greater, about 500 m 2 / g or greater, about 1000 m 2 / g or greater.

[0071] In one embodiment, the CO2-philic phase (e.g., a CO2-binding molecule) can be physically impregnated in the internal volume pores of the porous structure without covalently binding to the inner surface of the pores of the porous structure, can be grafted (e.g., directly or indirectly covalently bound) to the inner surface of the pores of the porous structure, or a combination thereof. In one embodiment, the CO2-philic phase (e.g., a CO2-binding molecule) can be covalently bound (e.g., directly to the surface or through a linking group) to the surface of the material, which can include the inner surface of the pores of a porous layer or a porous structure. In one aspect, the covalent binding can be achieved using techniques known in the art for binding adsorbents. Given that the CO2-philic phase (e.g., a CO2-binding molecule) is physically impregnated in the pores of the porous structure and not covalently bound to the inner surface of the pores of the porous structure, the CO2-philic phase can be confined within the pores of the carrier but not bound to the surface. In yet another embodiment, the CO2-philic phase (e.g., a CO2-binding molecule) is present in a plurality of pores (internal volume) of the porous structure (the "porous structure" can include a structure having pores on its surface or a structure having a porous layer or coating on the surface of the structure (where the structure itself can be or can not be porous)), wherein the loading amount of the CO2-philic phase is about 10% to 75% of the weight of the carrier. Regarding the loading amount, the loading amount is determined by thermogravimetric analysis (TGA).

[0072] In one embodiment, the carrier can include a surface layer on the surface of the carrier pores, which can combine with the CO2-philic phase. In one aspect, the surface layer can include organic modified moieties (e.g., alkyl, amine, thiol, phosphine, etc.) on the surface of the material (e.g., the outer surface and / or inner surface of the pores). In one embodiment, the surface layer can include surface alkyl, amine, thiol, phosphine, etc., and the CO2-philic phase can be directly covalently bound and / or indirectly covalently bound (e.g., covalently bound to a linker covalently bound to the material). In one embodiment, the surface layer can include an organic polymer having one or more of the following groups: alkyl, amine, thiol, phosphine, etc. In another embodiment, the structure can be a carbon carrier, wherein the carbon carrier can include one or more of the following groups: alkyl, amine, thiol, phosphine, etc.

[0073] In one embodiment, the specific loading of the CO₂-philic phase can be about 10% to 100% of the mesopore volume of the support, or the specific loading can be about 30% to 90% of the mesopore volume of the support, or the specific loading can be about 40% to 80% of the mesopore volume of the support, or the specific loading can be about 50% to 70% of the mesopore volume of the support.

[0074] The methods for making structured supports, shaped supports or structures described above and herein can be used to make any of the structures listed in this paragraph and the following paragraphs. An adsorbent comprising a CO₂-philic phase and a support can be formed or applied to the structure. In one aspect, the CO₂-philic phase and the support can form 100% or less than 100% of the structure (e.g., each combination between about 10%, about 20%, about 30%, about 40%, about 50% and about 60%, about 70%, about 80%, about 90%, about 99%, such as about 10% to 99%, about 10% to 80%, about 10% to 50%, about 50% to 99%, about 50% to 90%, about 50% to 80%), where there is a sufficient amount of adsorbent on the surface of the structure to absorb the desired amount of CO₂. In one aspect, the structure can be a honeycomb, laminate, foam, fiber, minimal surface solid, powder tray, pellet, powder, etc. or a combination of two or more of the foregoing.

[0075] In one aspect, the pores of the structure can consist of macropores, mesopores, and / or micropores. In one aspect, the CO₂-philic phase is mainly (e.g., about 40% to 100% or about 50% to 90%, or about 60% to 80%) located within the mesopores of the structure.

[0076] In one aspect, the structure can consist entirely of an adsorbent or can comprise another substrate material, such as a ceramic, metal, metal oxide, plastic, or another material. The structure can be a porous substrate or can include a porous coating on some or all parts of the porous substrate, where the CO₂-philic phase can be present in the pores of one or both of the porous substrate and the porous coating.

[0077] When the structure consists entirely of an adsorbent (e.g., a CO₂-binding molecule and a support), it can be formed by, for example, extrusion, molding, 3D printing, etc. The structure can be formed using a support material without a CO₂-philic phase or using a support that has already been combined with a CO₂-philic phase. When formed without using a CO₂-philic phase, the CO₂-philic phase can be incorporated into the structure by impregnation, grafting, or other functionalization techniques.

[0078] In a specific aspect, the carrier material can be applied to the substrate as a porous coating (also known as a "washcoat") on the substrate surface. In one embodiment, the porous coating can be a foam, such as a polymer foam (e.g., polyurethane foam, polypropylene foam, polyester foam, etc.), a metal foam, or a ceramic foam. The porous coating can include a metal oxide layer (e.g., a foam). For example, the metal oxide layer can be silica or alumina on the substrate surface. The porous coating can be present on the surface of the substrate, within the pores or voids of the substrate, or a combination thereof. The thickness of the porous coating can be from about 50 μm to 1500 μm, and the pore size can be as described above and herein.

[0079] In one aspect, the carrier material, substrate, and / or structure can be made of a ceramic substrate, such as cordierite, alumina (e.g., γ-alumina, θ-alumina, δ-alumina), cordierite-α-alumina, silica, aluminosilicate, zirconia, germanium oxide, magnesia, titanium dioxide, hafnium oxide, silicon nitride, zircon mullite, spodumene, alumina-silica magnesia, zirconium silicate, sillimanite, magnesium silicate, zircon, petalite, and combinations thereof. The metal or metal oxide structure can be aluminum, titanium, stainless steel, an Fe-Cr alloy, or a Cr-Al-Fe alloy. In the case where the oxide contains a formal charge, the charge can be balanced by appropriate counterions, 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, etc.

[0080] In one aspect, the carrier material, substrate, and / or structure can be made of a plastic substrate, which can be made of polyolefin, polyester, polyurethane, polycarbonate, polyetheretherketone, polyphenylene ether, polyethersulfone, melamine, polyamide, polystyrene divinylbenzene, polyurethane, polyacrylate, polystyrene, polyacrylonitrile, polyimide, polyfurfuryl alcohol, phenol furfuryl alcohol, melamine formaldehyde, resorcinol formaldehyde, cresol formaldehyde, phenol formaldehyde, polyvinyl alcohol dialdehyde, polycyanurate, polyacrylamide, various epoxy resins, agar, and agarose, or combinations thereof.

[0081] In one embodiment, the structure may be a honeycomb structure, such as a honeycomb monolith including channels. The honeycomb structure may have a regular corrugated structure. The length and width of the honeycomb monolith may be on the order of centimeters to meters, while the thickness may be on the order of millimeters to centimeters or more. In one aspect, the honeycomb monolith does not have a fiber size. In other words, the honeycomb structure may be a flow-through substrate including open channels defined by channel walls. The channels may have from about 50 to about 900 cells per square inch. The cross-section of the channels may be polygonal (e.g., square, triangular, hexagonal, octagonal), sinusoidal, circular, etc. Along the length of the channels, the channel length may have a straight, zigzag, skewed, or chevron configuration. The length of the channels may be from 1 millimeter to several tens or hundreds of centimeters or longer. The channels may have perforated or louvered walls. In one aspect, the adsorbent may be disposed in the pores of the honeycomb structure and / or in the pores of a porous layer on the surface of the honeycomb structure. The geometric porosity (also referred to as the open area) of the honeycomb structure may be from 0.3 to 0.95 or about 0.5 to 0.9.

[0082] In one embodiment, the honeycomb structure may include an inlet end, an outlet end, and internal channels extending from the inlet end to the outlet end. In some embodiments, the honeycomb includes a plurality of cells extending from the inlet end to the outlet end, the cells being defined by intersecting cell or channel walls.

[0083] In one aspect, the honeycomb structure and / or substrate may be ceramic (e.g., of the type sold under the trademark by Corning), which may be used with an adsorbent in accordance with the principles of the present disclosure. The adsorbent may be coated or otherwise fixed within the pores of the ceramic honeycomb structure and / or within a porous layer on the surface of the ceramic honeycomb structure. In one aspect, the porous coating may include a metal oxide layer on the substrate surface, such as silica or alumina. In one embodiment, the metal oxide layer may be mesoporous and macroporous. The depth of the honeycomb monolith may be from 3 inches to 10 feet, or about 3 to 24 inches.

[0084] In one aspect, the structure may be a laminate. A laminate is a structure including a one-dimensional wall structure, whereby the plates are stacked on top of each other with a space between each plate such that gas can flow between the plates.

[0085] In one aspect, the structure may be a foam. A foam is a structure having an irregular channel structure surrounded by an irregular solid structure. The solid structures are interconnected such that the foam material is self-supporting.

[0086] In one aspect, the structure can be multiple fibers. Fibers are structures with a high aspect ratio and, in gas contact applications, can be arranged in a regular array with respect to each other when supported at least at one end of the fiber. The fibers can be solid or hollow.

[0087] In one aspect, the structure can be a minimal surface solid. Minimal surface solids are structures often used in the packing of distillation and absorption systems to increase the contact area with materials and fluids. A minimal surface solid refers to a geometric shape with a zero average surface area, including shapes such as surfaces of revolution. For example, the surface of revolution can be sinusoidal.

[0088] In one aspect, the structure can be a powder tray. A powder tray is a structure in which the tray holds loose powder or pellets of the adsorbent of the present invention to form a structured contactor, while the material itself does not form a self - supporting structure. The powder trays can be arranged in stacked layers to form a plate, thereby forming a structure similar to a laminate. These layers can be formed using flexible plates, rigid plates, or other planes mounted on a rigid frame structure. The powder is a loose, free - flowing solid with a small characteristic particle diameter to provide a powdery consistency. The pellets are beads, spheres, or other dense structures used to provide structure and surface area for the adsorbent.

[0089] In one aspect, the structure can be a sorbent particle volume. The sorbent particle volume can be contained by one or more walls such that gas can pass through them while keeping the sorbent contained. The sorbent particle volumes can be arranged relative to other sorbent particle volumes, for example, similar to a honeycomb, fibers, or other structured contactors with solids.

[0090] In one aspect, an adsorbent in the form of a contactor (e.g., the structure) is an effective embodiment of an effective method for capturing CO2 from ambient air or other gas mixtures (e.g., flue gas, exhaust gas, natural gas, or other CO2 - containing gases) because the structured contactor or contactor can be designed to provide a high surface area and low pressure drop for air treatment. The contactor can be in the form of the aforementioned honeycomb, laminate, foam, fiber, minimal surface solid, powder tray, pellet, powder, or a combination of two or more of the foregoing forms.

[0091] Embodiments of the adsorbent and the structure have now been described, and details of the systems and methods of the present disclosure are provided. The present disclosure provides a method for capturing CO2 from ambient air or other gas mixtures (e.g., flue gas, exhaust gas, natural gas, or other CO2-containing gases). The method includes introducing ambient air into an adsorbent (e.g., a structure); heating the adsorbent (e.g., about 10 °C to 200 °C above the temperature of a conventional adsorbent for CO2 absorption) to at least a first temperature to controllably release CO2; and collecting the CO2 in a CO2 collection device. The temperature increase in the adsorbent can be effected by contacting the adsorbent with a gas at an elevated temperature, contacting the adsorbent with a fluid at an elevated temperature, contacting the adsorbent with a heat exchanger through which a hot fluid or gas flows, by heating the walls of a container, vessel, or other enclosed device containing the adsorbent, or by contacting the adsorbent with steam (e.g., the temperature of the steam can be between 60 °C and 200 °C and can be saturated or superheated). In one aspect, the method can be implemented using the system described below.

[0092] The present disclosure provides systems and devices for capturing CO2 from ambient air or other gas mixtures that require CO2 removal (e.g., flue gas, exhaust gas, natural gas, or other CO2-containing gases). Generally, the system includes a first device configured to introduce ambient air or other gas mixture into an adsorbent or a contactor, where the adsorbent or contactor includes those described herein. The adsorbent is exposed to the ambient air or other gas mixture for a period of time (e.g., several hours). In a particular aspect, the adsorbent is a honeycomb monolith having an open surface area of 0.3 to 0.95. The first device is configured to deliver the ambient air to the honeycomb monolith at a velocity of 0.25 m / s to 10 m / s. After a desired time, a second device is configured to heat the adsorbent containing the bound CO2 to at least a first temperature to release the CO2. The second device of the system can desorb the CO2 from the adsorbent. The second device can include components that support temperature swing, pressure swing, steam swing, concentration swing, combinations thereof, or other dynamic processes to desorb the CO2. In one embodiment, the steam swing process can include exposing the adsorbent 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 system can be operated such that the adsorbent absorbs and desorbs CO2 in an effective and cost-effective manner.

[0093] Embodiment

[0094] Removing CO2 from ambient air through engineered chemical processes, also known as direct air capture (DAC), is emerging as an important environmental technology for mitigating climate change. DAC is a technology that can provide negative emissions by removing CO2 from the atmosphere. However, current DAC technologies are expensive, which limits their application. Therefore, there is a need to improve DAC technologies. Many DAC technologies rely on solid adsorbent materials as the medium for separating CO2 from air. These adsorbents are typically applied in temperature swing processes, in which, at low temperatures, CO2 in the air binds to sites within them, and then, at high temperatures, the CO2 is released into a concentrated product that can be sequestered or sold as a product. Many DAC adsorbents use amines to bind CO2 in this way. Certain amine types can effectively bind CO2 at low concentrations (e.g., the concentration found in air (400 ppm)).

[0095] While some amine types are effective in binding CO2 from ambient air, they are slowly oxidized by ambient oxygen in air. This effect is exacerbated in the process cycle of raising the adsorbent temperature to remove the bound CO2, thereby accelerating oxidative degradation and shortening the lifespan of the CO2 adsorbent. Therefore, there is a need for adsorbents with improved oxidative stability that can effectively remove CO2 from ambient air.

[0096] Some adsorbents used in the DAC process are composite materials that contain a CO2-philic phase (e.g., CO2-binding molecules) distributed in or within a solid material, and the solid material provides a surface area for it. The CO2-philic phase can be grafted onto the solid surface, physically impregnated into the pores of the solid material, or physically loaded onto the surface of the solid material. The CO2-philic phase of these adsorbents can be an amine or other molecule capable of binding CO2. In some cases, the amine can be a polymeric amine, such as polyethyleneimine, polypropyleneimine, polyallylamine, polyvinylamine, polybutylamine, etc. These polymeric amines can be linear, branched, hyperbranched, dendritic, or take some other macromolecular form. In other cases, the amine can be a small molecule, such as TEPA, TPTA, etc. In other cases, the amine can be an aminosilane. The solid support material can be a metal oxide, carbon, metal, or other structure that can provide a sufficient surface area for the CO2-philic phase to be deposited, allowing for useful CO2 adsorption and desorption capacity and kinetics. In this way, the solid support material is functionalized with the CO2-philic phase to produce a composite adsorbent.

[0097] The adsorbent can be formed or incorporated into a macrostructure or contactor to provide advantages in applications such as DAC. Such a structure can be a honeycomb monolith, laminate, pellet, or other structure that can provide a high geometric surface area for air or CO2-containing gas to effectively contact the adsorbent so that CO2 can bind to the adsorbent.

[0098] The adsorbent can be used in the process of capturing CO2 from air or various other gas streams such as flue gas, natural gas, etc. These processes are referred to as "CO2 capture processes". The CO2 capture process can utilize temperature swing, concentration swing, pressure swing, stripping or other swing techniques to remove the CO2 that has been bound to the surface of the adsorbent.

[0099] The development of improving CO2 adsorbents using polyethyleneimine is relatively less, especially for DAC applications.

[0100] Now that the embodiments of the present disclosure have been described, generally speaking, the following examples describe some additional embodiments of the present disclosure. Although the embodiments of the present disclosure are described in conjunction with these examples and the corresponding text and drawings, it is not intended to limit the embodiments of the present disclosure to these descriptions. On the contrary, it is intended to cover all substitutions, modifications, and equivalents included within the spirit and scope of the embodiments of the present disclosure.

[0101] Example: Schematic diagram showing an adsorbent having a support material and a CO2-philic phase

[0102] Figure 1B The main components of the adsorbent system are shown. The adsorbent system consists of a support material and a CO2-philic phase. In the schematic diagram shown, a single CO2-philic phase is shown combined with a single support. The shown CO2-philic phase is polyethyleneimine (PEI). A known adsorption product of CO2 and PEI is ammonium carbamate. Mesoporous alumina is shown as the support.

[0103] Example: Schematic diagram of a honeycomb monolith structure containing an adsorbent support coating

[0104] Figure 2 An embodiment of a honeycomb monolith contactor is shown. The adsorbent support coating consists of a support and a CO2-philic phase. This example shows a cordierite substrate, an alumina support, and a PEI CO2-philic phase. Figure 2 The main geometric feature of the honeycomb monolith is shown - a straight through-channel formed by circumferential walls enclosing it. Figure 2 The carrier coating on the wall is schematically shown. The carrier coating consists of an adsorbent. The adsorbent contains a support material and a CO2-philic phase (such as PEI).

[0105] Example: Evaluation of glycidyl ether as a modifier for polyethyleneimine (PEI)

[0106] The effect of reducing the oxidation rate when various glycidyl ethers are incorporated into the support after reacting with PEI was evaluated. For the glycidyl ethers and their drawing numbers, see Figure 3 .

[0107] Example: Synthesis of Glycidyl Hexyl Ether (GHE) and Glycidyl Octyl Ether (GOE)

[0108] Since commercial glycidyl hexyl ether and glycidyl octyl ether are not available as starting materials, they need to be synthesized by themselves. Figure 4 The synthetic routes of these two compounds are shown. To prepare GHE and GOE, 1-hexanol or 1-octanol was added to the reaction bottle and heated to 40°C, and KOH and tetrabutylammonium hydrogen sulfate (TBAHS) were added to maintain the temperature in the range of 38°C to 42°C. The solution was stirred for 30 minutes, epichlorohydrin was added dropwise, and the reaction was stirred for 12 hours at 42°C. After the reaction was completed, the product was extracted with n-hexane and finally purified by reduced pressure distillation at 80 mTorr vacuum and 60°C.

[0109] Example: Preparation of an improved CO2-philic phase comprising the reaction product of polyethyleneimine (PEI) and a glycidyl ether

[0110] Branched polyethyleneimine (PEI, molecular weight 800) was purchased from SigmaAldrich. The glycidyl ethers used are listed in Figure 3 The general scheme for the reaction of PEI with glycidyl ether is as follows: Figure 5 As shown. PEI is dissolved in a methanol solution, and then a single glycidyl ether is added at a ratio of 0.5 mol of glycidyl ether per mol of primary amine in PEI. The mixture is stirred and reacted at room temperature or 80°C for 12 hours under argon protection to allow the glycidyl ether to react with PEI. The solvent is then evaporated and the modified PEI is dried in vacuo.

[0111] The reaction product of PEI and glycidyl ether is then dispersed in methanol and homogeneously mixed. The mesoporous alumina is then added to the reaction product / methanol dispersion of PEI and glycidyl ether. The solvent is removed by rotary evaporation after stirring for 12 hours, and then vacuum dried for 12 hours. The mass ratio of alumina and the reaction product of PEI and glycidyl ether is controlled to achieve 40% to 80% filling of the reaction product of PEI and glycidyl ether in the mesoporous alumina. The resulting composite adsorbent is in powder form.

[0112] Example: Characterization of Improved CO2-Affinic Phases and CO2 Adsorbents

[0113] Chemical characterization was performed to confirm the nature of the support and the improved CO2-philic phase. Further chemical characterization was performed to confirm that these CO2-philic phases were successfully incorporated into the pores of the mesoporous support, thereby producing an improved CO2 adsorbent.

[0114] PEI and the materials obtained by reacting PEI with various glycidyl ethers 1 H NMR experiments were performed to characterize the properties of the obtained materials.

[0115] FTIR experiments were conducted on the adsorbent containing the improved CO₂-philic phase and mesoporous support to characterize the properties of the adsorbent.

[0116] TGA burnout experiments were carried out on the adsorbent composed of the improved CO₂-philic phase and mesoporous support to characterize the total amount of organic matter present in the adsorbent. The sample was heated to 900 °C in diluted air, and its mass loss was tracked. After removing the influence of CO₂ and H₂O lost at lower temperatures, the total organic matter content was taken as the mass loss in this temperature range.

[0117] N₂ physical adsorption experiments were performed on the blank mesoporous support and the adsorbent containing the improved CO₂-philic phase and mesoporous support to characterize the porosity and pore filling of the adsorbent.

[0118] Example: HNMR spectra of PEI and the improved CO₂-philic phase generated by the reaction of PEI with glycidyl ether 1 HNMR spectra

[0119] Figure 6 Show the HNMR spectra of PEI (upper figure) and the reaction product of PEI and glycidyl octyl ether (0.5 moles of glycidyl ether per mole of primary amine in PEI) (lower figure). After the glycidyl ether was functionalized with PEI, a new peak was introduced at 3.8 ppm, which corresponds to the tertiary carbon atom substituted by two CH₂ groups and one hydroxyl group. This peak indicates that the glycidyl ether has undergone ring-opening and the reaction between PEI and glycidyl ether is complete. The triplet at 0.89 ppm is the methyl group at the end of the alkyl chain, and the peaks in the range of 2.4 ppm to 3 ppm come from the methylene CH₂ on the PEI chain. 1 HNMR spectra

[0120] Example: TGA burnout experiments

[0121] Figure 7 shows the mass loss curve and the heat flow (DSC) curve of the material during exposure to diluted air while the temperature was raised from room temperature to 900 °C. This figure shows that both the original PEI and the modified PEI adsorbent lost a large amount of mass during the experiment, which is due to the combustion of the organic components in the material under oxidative conditions.

[0122] Example: Tests during the CO₂ adsorption process

[0123] The adsorbent produced with the improved CO₂-philic phase was tested for CO₂ adsorption in a TGA at 400 ppm CO₂ and 30 °C to simulate the gas contact step in a direct air capture process. The adsorbent was first treated at 100 °C in an inert gas to desorb any bound H₂O and CO₂. Then, the gas concentration was isothermally switched to contain 400 ppm CO₂ with the balance being He, and the mass change was recorded.

[0124] This method was used to characterize the CO2 adsorption of various improved adsorbents and compare them with a benchmark PEI-based adsorbent. The adsorbents were evaluated based on two metrics: i) CO2 capacity (mmol of CO2 adsorbed per mol of adsorbent present); ii) amine efficiency (mmol of CO2 adsorbed per mol of N in the PEI or glycidyl ether-modified PEI present in the sample). The former performance unit can be used to demonstrate the performance of the overall adsorbent, while the second performance unit helps to evaluate the performance of the amine polymer itself and takes into account the variations in the overall composition of the adsorbent.

[0125] Example: CO2 adsorption of PEI and improved CO2-philic phases loaded on mesoporous alumina at 400 ppm CO2.

[0126] Figure 8 Shown is a comparison of the transient TGA adsorption curves of adsorbents produced from improved CO2-philic phases (using reaction products of PEI with butylene oxide, PEI with hexylene oxide, and PEI with octylene oxide, all at 0.5 mol glycidyl ether / mol primary amine in PEI) and adsorbents produced from unmodified PEI under DAC conditions. While each adsorbent was able to adsorb CO2 at DAC concentrations, the amine efficiency appeared to decrease with increasing epoxy ether chain length.

[0127] Example: Oxidation stability test

[0128] The oxidation stability of the materials was investigated by two methods. The first method was to measure the CO2 capacity of the adsorbent after exposing it to an isothermal oxidation environment for a certain period of time, following the method described above. The adsorbent was exposed to two different oxidation environments: one containing dry O2 and the other containing moist O2. In both cases, the adsorbent was first treated in an inert gas at 100 °C to desorb any bound H2O and CO2, and then equilibrated in (dry / moist) inert gas at the target temperature for 60 minutes. For the dry experiment: the adsorbent was first equilibrated in dry inert gas at 120 °C, and then the gas was switched isothermally to a 17% O2 mixture and held at 120 °C for 3 hours to partially oxidize the sample. For the moist experiment: the adsorbent was first equilibrated in inert gas at 137 °C and 50% relative humidity, and then the gas was switched isothermally to a 21% O2 mixture at 50% relative humidity and 137 °C and held for 3 hours to partially oxidize the sample.

[0129] Another method for evaluating the oxidative stability of adsorbents is to use DSC to track the heat flow released by the material under isothermal oxidation conditions. Here, the adsorbent is first treated at 100 °C in an inert gas to desorb any bound H2O and CO2, and then equilibrated at 137.5 °C in an inert gas for 60 minutes. The gas is then isothermally switched to a 17% O2 mixture and held for 14 hours. This isothermal oxidation environment is maintained for a specific amount of time to measure the heat flow and mass loss. To prevent any further oxidation, the sample is then cooled to room temperature under N2. In these experiments, for each oxidation condition, DSC measures the increment of the heat flux, which increases, stabilizes, and then drops to zero. Oxidation is considered complete when the change in the integrated heat flow within 10 minutes is less than ±0.01% of the total integrated heat. To determine the relationship between the degree of oxidation and time, the DSC data is converted from the basic unit of mW / mg adsorbent to W / g PEI using the PEI loading measured by TGA burnout. The drift of the DSC data is offset-corrected by determining the heat flow value when the DSC curve approaches the horizontal line. The total heat released is calculated by integrating the heat flow over time. The degree of oxidation by DSC is calculated by dividing the integrated heat flow curve by the total heat released. This method has been calibrated previously with the loss of amine efficiency as a method for in-situ tracking the chemical reaction rate of oxidative degradation, as shown in Figure 9. More details about this method and its validation will be 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. This paper is incorporated herein by reference.

[0130] Figure 10Shows the oxidation degree curves obtained by DSC heat flow measurement of the modified CO2 adsorbents (containing the reaction products of PEI with glycidyl methyl ether (GME), the reaction products of PEI with glycidyl ethyl ether (GEE), the reaction products of PEI with glycidyl butyl ether (GBE), the reaction products of PEI with glycidyl hexyl ether (GHE), and the reaction products of PEI with glycidyl octyl ether (GOE), at 0.5 mol glycidyl ether / mol primary amine in PEI) under isothermal oxidation conditions of 137.5 °C and 17% O2 for 14 hours, and compares with the test of the unmodified PEI adsorbent under the same conditions. It can be seen that the adsorbents of all reaction products of PEI with glycidyl ethers have better oxidation stability than the unmodified PEI adsorbent. It can also be seen that the modification effects of different glycidyl ethers are different, and the improvement of oxidation stability shows the following trend: PEI-0.5GHE > PEI-0.5GBE > PEI-0.5GOE > PEI-0.5GEE ≈ PEI-0.5GME > PEI. The data indicate that increasing the glycidyl ether chain length can improve the oxidation stability within a certain threshold, and may tend to level off or start to decline after exceeding this threshold. The data show that glycidyl ether is an effective modifier for improving the oxidation stability of amine polymer adsorbents.

[0131] Figure 11 Shows the CO2 absorption curves expressed in amine efficiency (mmol CO2 / mmol N) after oxidation treatment under dry conditions, for exploring the relative oxidation stability of the adsorbents. Figure 11 Indicates that compared with unmodified PEI (see Table 1 below), each adsorbent containing modified PEI can maintain a higher amine efficiency (compared to its initial value). This shows that the modification of PEI forms an improved CO2-philic phase with stronger antioxidant degradation ability, thus providing a more stable adsorbent for the DAC process.

[0132] Figure 12 Shows the CO2 adsorption curves expressed in amine efficiency (mmol CO2 / mmol N) after oxidation treatment under wet conditions, for exploring the relative oxidation stability of each adsorbent. Figure 12 Indicates that compared with unmodified PEI (see Table 1), each adsorbent containing modified PEI can maintain a higher amine efficiency (compared to the initial value). This shows that the modification of PEI forms a CO2-philic phase with stronger antioxidant degradation ability, thus providing a more stable adsorbent for the DAC process.

[0133] Table 1: Characteristics and performance of adsorbents produced using PEI and PEI modified with glycidyl ether.

[0134]

[0135]

[0136] Table 1 shows the physical properties of the fresh samples, the CO2 adsorption performance, and the CO2 adsorption performance of the samples after oxidation treatment under dry and wet conditions. This table shows the performance of adsorbents containing PEI and the reaction products of PEI with glycidyl ethers GME, GEE, GBE, GHE, and GOE (at 0.5 moles of glycidyl ether per mole of primary amine in PEI). Whether in a dry or wet environment, the loss of amine efficiency after oxidation of the unmodified PEI adsorbent is significantly higher than that of the PEI adsorbents reacted with glycidyl ethers.

[0137] Examples:

[0138] Figure 13 Shows the structures of glycidyl ethers that can react with amines to form an improved CO2-philic phase.

[0139] It should be noted that ratios, concentrations, amounts, and other numerical data may be expressed in the form of ranges herein. It should be understood that such range forms are used for convenience and brevity and should, therefore, be interpreted in a flexible manner to include not only the explicitly recited values as the limits of the range but also all individual values or sub-ranges subsumed within that range as if each value and sub-range were explicitly recited. For illustration, a concentration range of "about 0.1% to about 5%" should be interpreted to include not only the explicitly recited concentrations of about 0.1 wt% to about 5 wt% but also the individual concentrations (e.g., 1%, 2%, 3%, and 4%) and sub-ranges (e.g., 0.5%, 1.1%, 2.2%, 3.3%, and 4.4%) within the indicated range. In one embodiment, "about 0" may refer to 0, 0.001, 0.01, or 0.1. In one embodiment, the term "about" may include conventional rounding according to the significant figures of the numerical value. Additionally, the phrase "about 'x' to 'y'" includes "about 'x' to about 'y'".

[0140] It should be emphasized that the above-described embodiments of the present disclosure are merely exemplary embodiments that are possible and are set forth merely to clearly understand the principles of the present disclosure. Many variations and modifications can be made to the above-described embodiments of the present disclosure without materially departing from the spirit and principles of the present disclosure. All such modifications and variations are intended to be included within the scope of the present disclosure.

Claims

1. An adsorbent, comprising: A CO2-philic phase and a support, wherein the CO2-philic phase comprises a reaction product of an amine and a glycidyl ether.

2. The adsorbent according to claim 1, wherein the amine is an amine polymer.

3. The adsorbent according to claim 2, wherein the amine polymer is branched, hyperbranched, dendritic or linear.

4. The adsorbent according to claim 3, wherein the amine polymer is one of polyethyleneimine, polypropyleneimine, polyallylamine, polyvinylamine, polyglycidylamine or an amine-functionalized polystyrene-divinylbenzene polymer.

5. The adsorbent according to claim 1, wherein the CO2-philic phase is homogeneous.

6. The adsorbent according to claim 1, wherein the CO2-philic phase is heterogeneous.

7. The adsorbent according to claim 1, wherein the fraction of the amine modified by reaction with the glycidyl ether is about 0.001 to 1 of the total primary and secondary amines in the amine polymer, where a fraction of 1 means that all amines are primary and secondary amines.

8. The adsorbent according to claim 1, wherein the fraction of the amine modified by reaction with the glycidyl ether is about 0.01 to 0.5 of the total primary and secondary amines in the amine polymer, where a fraction of 1 means that all amines are primary and secondary amines.

9. The adsorbent according to claim 2, wherein the amine is physically impregnated into the pores of the support.

10. The adsorbent according to claim 2, wherein the amine is physically impregnated onto the surface of the support.

11. The adsorbent according to claim 2, wherein the amine is covalently bonded to the surface of the support.

12. The adsorbent according to claim 1, wherein the glycidyl ether is selected from: glycidol, methyl glycidyl ether, ethyl glycidyl ether, butyl glycidyl ether, hexyl glycidyl ether, octyl glycidyl ether, isopropyl glycidyl ether, tert-butyl glycidyl ether, (R)-phenyl glycidyl ether, allyl glycidyl ether, 1,4-bis(glycidyloxy)benzene or a mixture thereof.

13. The adsorbent according to claim 1, wherein the CO2-philic phase comprises at least one structure selected from the following structures, where R x is a substituted group: Wherein R1 is selected from a hydrogen atom, a halogen, a straight-chain or branched alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a benzyl group, a phenol group or a heteroaryl group, and each R' is independently selected from a hydrogen atom, an alkyl group, an alkoxy group, a haloalkyl group, an aryl group, a benzyl group, a phenyl group, a phenol group, an amine group or a heteroaryl group.

14. The adsorbent according to claim 1, wherein the support is a ceramic, metal, metal oxide, plastic, cellulose, carbon, zeolite, metal-organic framework (MOF), porous organic framework (POF), covalent organic framework (COF), intrinsically microporous polymer (PIM), polymer, fibrous cellulose, glass fiber or boron nitride fiber.

15. A contactor, comprising a structure and the adsorbent according to any one of claims 1 to 14.

16. The contactor according to claim 15, wherein the structure is selected from a honeycomb, a laminate, a foam, a fiber, a minimal surface solid, a powder tray, a pellet or a combination thereof.

17. A system for capturing CO2 from a gas, optionally the gas is ambient air, the system comprising: A first device configured to introduce a gas to the adsorbent or contactor according to any one of claims 1 to 16 to bind CO2 to the adsorbent; A second device configured to heat the adsorbent containing the bound CO2 to at least a first temperature to release the CO2; and A third device configured to collect the released CO2.

18. The system according to claim 17, wherein after heating, the adsorbent is regenerated such that the adsorbent is capable of absorbing CO2 from the gas.

19. The system according to claim 17, wherein the adsorbent is in the form of: honeycomb, laminate, foam, fiber, minimum surface solid, powder tray, pellet, and combinations thereof.

20. The system according to claim 19, wherein the open face area of the honeycomb is about 0.3 to 0.

95.

21. The system according to claim 20, wherein the gas approaches the honeycomb at a velocity of about 0.25 m / s to 10 m / s.

22. The system according to claim 20, wherein the system is configured to operate to remove CO2 from ambient air, wherein the ambient air has a low concentration of CO2.

23. A method for capturing CO2 from a gas, optionally the gas is ambient air, the method comprising: Introducing the ambient air to the adsorbent according to any one of claims 1 to 16 to bind CO2 to the adsorbent; Heating the adsorbent to at least a first temperature to controllably release the CO2; and Collecting the CO2 in a CO2 collection device.

24. The method according to claim 23, wherein heating the adsorbent regenerates the adsorbent such that the adsorbent is capable of absorbing CO2 from ambient air.

25. The method according to claim 23, wherein the adsorbent is heated by contacting the adsorbent with steam.

26. The method according to claim 23, wherein the method is configured to operate to remove CO2 from ambient air, wherein the ambient air has a low concentration of CO2.

27. The method according to claim 23, wherein the adsorbent is in the form of: honeycomb, laminate, foam, fiber, minimum surface solid, powder tray, pellet, and combinations thereof.

28. A system for implementing the method according to any one of claims 23 to 27.

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