Carbon dioxide capture and release with amine-functionalized (METH)acrylic polymers and systems related thereto

Abstract

Compositions containing amine-functionalized polymers may be configured to promote capture and release of carbon dioxide. Compositions suitable for capturing carbon dioxide from a fluid may comprise an amine-functionalized polymer, and at least one additional moiety configured to promote binding of carbon dioxide by the amine-functionalized polymer or to promote release of carbon dioxide from the amine-functionalized polymer. A proton ionizable group that deprotonates differentially as a function of temperature may comprise at least a portion of the additional moieties. The one or more additional moieties or the amine- functionalized polymer may accomplish one or more of the following to promote binding and release of carbon dioxide: lowering the dielectric constant of water, providing buffering, lowering pKa, providing surfactancy, providing a bound metal, or any combination thereof. The one or more additional moieties may be covalently bonded to the amine-functionalized polymer or blended with the amine-functionalized polymer as a small-molecule additive.

Description

CARBON DIOXIDE CAPTURE AND RELEASE WITH AMINE-FUNCTIONALIZED (METH)ACRYLIC POLYMERS AND SYSTEMS RELATED THERETOCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of U.S. Provisional Application No. 63 / 605,889, filed on December 4, 2023, which is incorporated herein by reference in its entirety.FIELD

[0002] The present disclosure generally relates to contaminant remediation and, more particularly, capture and release of carbon dioxide.BACKGROUND

[0003] There are increasing global efforts to reduce carbon dioxide emissions and even potentially capture excess carbon dioxide from the atmosphere. There is tremendous interest in capturing carbon dioxide directly from the atmosphere, since doing so would enable a truly circular carbon economy. Despite continuing interest in strategies for capturing carbon dioxide, there are still limited options for capturing and subsequently releasing carbon dioxide in an energy-efficient manner. This is particularly true for direct capture of carbon dioxide from the atmosphere, which has a concentration of only approximately 400 parts per million (ppm) (0.04%). This can be problematic for subsequent concentration of the captured carbon dioxide to a carbon dioxide content greater than about 97%, for example, for use or storage.

[0004] Carbon dioxide is released as a combustion byproduct and may also be frequently found in industrial process streams. For example, significant amounts of carbon dioxide are produced during commercial synthesis of ammonia, and carbon dioxide is often found as an acid gas impurity in natural gas streams. Capturing of the carbon dioxide may make the natural gas suitable for an intended use and also protect downstream equipment contacting the natural gas from corrosion and other deleterious effects. Other acid gases, such as hydrogen sulfide, may be captured concurrently using similar capturing agents to those used for capturing carbon dioxide.

[0005] Unless a capturing agent is sacrificial (non-reusable), the carbon dioxide eventually needs to be released to regenerate the capturing agent. To this end, release of captured carbon dioxide may be performed when delivering the carbon dioxide to a desired storage location (e.g., in asubterranean reservoir) or converting the carbon dioxide into a high-value chemical. While a number of strategies for capturing carbon dioxide are known, either in the form of carbonates or carbamates, the excessive energy demand of the release stage renders many of these capturing strategies problematic. Indeed, the energy required to liberate carbon dioxide from some capturing agents may generate nearly as much or even more carbon dioxide than was originally captured. For example, potassium hydroxide is very effective for capturing carbon dioxide in the form of a carbonate species, but calcination of the carbonate species to regenerate carbon dioxide may require an energy input corresponding to release of about 50% or more of the carbon dioxide that was originally captured. In essence, capturing carbon dioxide in this manner takes advantage of favorable kinetic and thermodynamic properties associated with forming a carbonate species, but ignores the penalty of reverting the carbonate species back to carbon dioxide, including the issues associated with high pH and a phase change. Although green energy sources may mitigate this issue to some degree, the energy inefficiency is still excessively high. In addition to an excessive energy demand, the water demand of capturing strategies based upon potassium hydroxide are also rather high.

[0006] Amines are a class of capturing agent that may be used for capturing and subsequently releasing carbon dioxide. Aqueous amine solutions are commonly used in this regard. Water-miscible organic solvents such as glycol ethers and glycol ether alcohols may be used in a similar manner as a carrier for the amine. The capturing chemistry of amines is very sensitive to pH and chemical structure, and the capturing kinetics tend to be slower than for potassium hydroxide and other caustics. To account for the slow capturing kinetics, an amine solution may be recirculated through an absorber tower to capture increasing amounts of carbon dioxide over time. Although amines may be less effective than potassium hydroxide and other caustics for promoting capture of carbon dioxide, the carbon dioxide may be released from amines much more readily.

[0007] Many strategies for capturing carbon dioxide utilize a capturing agent dispersed in aqueous media. However, carbon dioxide has a rather low solubility in aqueous media (<1 wt% solubility, even at a pressure as high as 10 atm), thereby limiting the amount of carbon dioxide that may be captured. Although recirculation of the aqueous fluid may increase the amount of carbon dioxide that is captured, such approaches may increase the time and expense needed to sequester a given quantity of carbon dioxide. Moreover, the composition of the aqueous fluid may change dynamically over time and alter the efficiency with which carbon dioxide undergoes sequestration therein.

[0008] As such, there remain numerous issues associated with carbon dioxide capture and release that have yet to be adequately resolved. The present disclosure addresses these needs and provides related advantages as well.BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure.

[0010] FIGS. 1 A and IB are diagrams of a macroparticulate formed from an epoxide- containing (meth)acrylic polymer or copolymer before and after functionalization, respectively.

[0011] FIGS. 2A and 2B show diagrams of a remediation system employing an amine-functionalized polymer disposed in removable cartridges in a swing bed arrangement.

[0012] FIGS. 3 A and 3B show diagrams of a remediation system employing an amine-functionalized polymer disposed in removable cartridges located upon a movable assembly.

[0013] FIGS. 4A and 4B show diagrams of illustrative movable assemblies containing removable cartridges containing an amine-functionalized polymer.

[0014] FIGS. 5 and 6 are plots of outlet carbon dioxide pressure during uptake as a function of carbon dioxide exposure time for various concentrations of amine-functionalized polymer.

[0015] FIGS. 7 and 8 are plots of outlet carbon dioxide pressure during release as a function of carbon dioxide exposure time for various concentrations of amine-functionalized polymer.

[0016] FIG. 9 is a graph showing the amount of carbon dioxide taken up or released by the amine-functionalized polymer as a function of carbon dioxide exposure time or heating time.

[0017] FIG. 10 is a graph showing the amount of carbon dioxide released by the amine-functionalized polymer as a function of time in the presence of 4-methoxyphenol.DETAILED DESCRIPTION

[0018] The present disclosure generally relates to contaminant remediation and, more particularly, capture and release of carbon dioxide.

[0019] As discussed above, it is presently difficult to capture and release carbon dioxide in an energy-efficient manner. The present disclosure addresses the foregoing difficulties and provides related advantages as well. In particular, the present disclosure provides compositions containing amine-functionalized polymers that may facilitate capturing of carbon dioxide in a desired form, either as a carbonate species or a carbamate (or even as dissolved carbon dioxide), and also promote subsequent release of the carbon dioxide in an energy-efficient manner. More specifically, the present disclosure provides compositions containing amine-functionalized polymers that may capture carbon dioxide in a desired form, wherein compositions may further incorporate one or more additional functionalities configured to promote uptake and ready release of the carbon dioxide at a desired time, wherein the one or more additional functionalities are located upon the amine- functionalized polymer or upon small-molecule additives that may be blended with the amine-functionalized polymer to promote uptake and release of carbon dioxide. That is, the additional functionalities may be present as additional functional groups upon the amine- functionalized polymer, as small-molecule additives blended with the amine-functionalized polymer, or combinations of the foregoing. In addition, combinations of two or more amine- functionalized polymers bearing different types of functionalities (or small-molecule additives blended therewith) may be utilized to promote carbon dioxide uptake and release according to the disclosure herein. Multiple types of additional functionalities may further alternately be covalently bonded to a single amine-functionalized polymer. Selection of the additional functionalities and how the additional functionalities contribute to capture and release of carbon dioxide are discussed hereinafter.

[0020] Amine-functionalized polymers represent a very versatile polymer material for accomplishing the foregoing. At the very least, the amines may promote bonding of carbon dioxide, either as a carbonate species or a carbamate (or even as unbound, dissolved carbon dioxide), depending on the pH and local conditions of the chemical environment where the carbon dioxide capture takes place. The amount and identity of the amines functionalizing the polymer may be selected based upon their affinity and / or selectivity for promoting carbon dioxide sequestration as a carbamate or a carbonate, as well as their ability to modify thelocal pH environment to provide pH matching that is more compatible with sequestration and subsequent release of carbon dioxide, preferably by providing bound carbon dioxide predominantly as a bicarbonate species. The bicarbonate species may arise from a lower pH environment resulting from use of lower basicity amines. Surprisingly, lower-basicity amines may be more effective than are higher-basicity amines for promoting carbon dioxide uptake and release in the disclosure herein. Because amines are weak bases, they may also promote buffering of aqueous solutions used in conjunction with carbon dioxide capture. Other Bronsted acids and Lewis acids or bases may provide buffering in a similar manner. In addition to themselves facilitating capture of carbon dioxide, amines are a chemically reactive group that may be further modified to introduce additional functionalities that may contribute to carbon dioxide capture and release, as described hereinafter.

[0021] The low solubility of carbon dioxide in aqueous fluids is believed to result from mismatch of the dielectric constants of these two media, as well as the surface tension of water as it relates to the phase boundary with gaseous carbon dioxide. While these difficulties may be addressed to some degree by adding water-miscible organic solvents to an aqueous fluid to encourage carbon dioxide uptake, use of even environmentally friendly organic solvents is undesirable from a commercial perspective and contributes to increased operational costs for sequestering carbon dioxide. Moreover, organic solvents tend to evaporate over time and need to be replenished periodically, thereby leading to process complexity. Advantageously, amine-functionalized polymers may be rendered water-soluble through choice of the amine, wherein the water-soluble amine-functionalized polymer may likewise alter the dielectric constant of the aqueous fluid to facilitate increased carbon dioxide solubility but without the risk of evaporation. The water-soluble amine- functionalized polymer may be utilized alone for capturing carbon dioxide or in combination with a water-insoluble amine-functionalized polymer to promote capture of carbon dioxide within the aqueous fluid and at an interface between the aqueous fluid and the waterinsoluble amine-functionalized polymer. Unlike organic solvents and small-molecule additives, water-soluble amine-functionalized polymers do not evaporate to result in variable solubility of carbon dioxide over time. Particular examples of water-soluble amine- functionalized polymers are discussed in more detail below. Advantageously, at least some of the amines that promote water solubility may also be lower-basicity amines, which may be advantageous for the reasons discussed above. Thus, a single type of amine-functionalizedpolymer may be effective to promote lowering of the dielectric constant and lowering of pH to provide advantaged uptake and release of carbon dioxide.

[0022] As indicated above, pH may impact the capture and release of carbon dioxide. The amine-functionalized polymers may incorporate a pH-modifying moiety as an additional functionality that may change the local pH environment under desired conditions to promote release of carbon dioxide in an energy -efficient manner at a desired time. The additional functionality may comprise a proton ionizable group. As a non-limiting example, one or more of the additional functionalities may include a group that differentially ionizes (deprotonates) with temperature, which may alter the local pH environment to promote release of the carbon dioxide. In some examples, the proton ionizable group may have a pKawithin about 1 unit higher (less acidic) than the pKaof a carbon dioxide species being captured. As the acidity increases with temperature (pKabecomes smaller), the proton ionizable group may then facilitate release of the carbon dioxide. Phenols are one example of an additional functionality exhibiting this behavior. Values outside this pKawindow may also be suitable. At higher temperatures, phenols deprotonate more completely and impact the local pH environment to a greater degree. The more acidic pH environment that results may encourage more complete and easier release of carbon dioxide. Essentially, the phenol or a similar proton ionizable group exhibiting similar behavior may allow the temperature at which carbon dioxide release takes place to be tuned through choice of the pKaof the phenol. Additional electron-withdrawing groups or electron-donating groups may be present upon the aromatic ring to further tune the acidity of the phenol, if needed. Phenols may be introduced to the amine-functionalized polymers through an amidation reaction, for example, such as by performing amidation of an amine group of a polyamine-functionalized polymer. Other strategies for introducing bound phenols to an amine-functionalized polymer are also possible and are discussed in further detail herein. Although advantageous when present upon the amine-functionalized polymer, the phenol or similar proton ionizable groups may also be blended with the amine-functionalized polymer as a small molecule additive.

[0023] Surfactants may lower the surface tension of an aqueous fluid and possibly promote formation of a foam or similar low-density form in some cases. By incorporating a surfactant at a gas-liquid interface, increased uptake of carbon dioxide may be realized by increasing gas flux. As discussed further below, amine-functionalized polymers may be further chemically modified with additional functionality that may exhibit surfactantproperties. For example, amine-fun ctionalized polymers may be functionalized using a phosphorane or sultone reagent to install a phosphoric acid derivative, such as a phosphoramidate, or sulfonic acid onto the amine-functionalized polymers to provide a reaction product that is sufficiently amphiphilic to provide surfactancy. Other amphiphilic functionalities may be introduced by reacting an amine group within the amine- functionalized polymers as well. For example, amine-functionalized polymers bearing an amphoteric group resembling a phosphatidylcholine head group may be produced through amine functionalization. Although advantageous when present upon the amine- functionalized polymer, a group exhibiting surfactancy may also be blended with the amine- functionalized polymer as a small molecule additive. In some examples, the biosurfactant lecithin may be utilized in this regard.

[0024] Metal ions, particularly transition metal ions, may catalyze uptake of carbon dioxide by the amine-functionalized polymers in some cases. Amine-containing ligands may be utilized to produce the amine-functionalized polymers disclosed herein, wherein the resulting polymer-tethered ligand may bind a metal ion suitable to catalyze carbon dioxide uptake. Examples of suitable ligands and metal ions that may be present within the amine- functionalized polymers are described further below. Although advantageous when present upon the amine-functionalized polymer, the ligand and bound metal may also be blended with the amine-functionalized polymer as a small molecule additive (e.g., as a metal complex). Zinc and coppers ions are non-limiting examples of metal ions that may be suitable to promote uptake and release of carbon dioxide in the disclosure herein.

[0025] Again, it is to be emphasized that the foregoing additional functionalities may be present upon a single amine-functionalized polymer (e.g., multiple additional functionalities upon a single amine-functionalized polymer), blends of amine-functionalized polymers having different additional functionalities, and / or small-molecule additives blended with one or more amine-functionalized polymers to provide the additional functionalities. Depending on their intended function and whether additional functionalities are present thereon, the amine-functionalized polymers may be soluble in aqueous fluids or insoluble in aqueous fluids, and if insoluble in an aqueous fluid, the amine-functionalized polymers may be present in a wide variety of morphological forms, as discussed hereinbelow.

[0026] In non-limiting examples, the additional functionalities for promoting carbon dioxide uptake and release by compositions containing the amine-functionalized polymer(s)may include one or more of a dielectric modifying moiety, a surface tension modifying moiety, a pH-modifying moiety (including acidic groups, basic groups, a buffering moiety, or salts thereof), an amphiphilic (surfactant) moiety, and / or metal ions or a complex thereof, each of which may contribute individually or collectively to promote sequestration and release of carbon dioxide. The amine of the amine-functionalized polymer may fulfill one or more of these roles, or an amine group may be functionalized to introduce a moiety having a specified function that may accomplish one or more of these roles. The additional functionalities may operate in cooperation with one another to promote carbon dioxide capture and release. All of the foregoing additional functionalities and their associated roles may be present in some instances, whereas in other instances not all of the various additional functionalities need to be present to achieve satisfactory carbon dioxide uptake and release. Thus, any combination of the foregoing additional functionalities may be present in the present disclosure. Depending on the pH environment and other environmental parameters, created at least in part by the amine-functionalized polymer and the additional functionalities that are present, carbon dioxide may be sequestered in the form of a carbamate or as a carbonate salt (or even as unbound, dissolved carbon dioxide). Preferably, the amine- functionalized polymer and the additional functionalities may work in cooperation to promote sequestration of the carbon dioxide as a bicarbonate, which may occur in a lower pH environment than occurs with caustics and higher basicity amines.

[0027] The Henderson-Hasselbach Equation (Equation 1) describes the relationship between pKaand pH, wherein pKais the -logio Ka, Kais the acid dissociation constant, [HA] is the concentration of the acid form of a weak acid, and [A‘] is the concentration of the conjugate base of a weak acid. pH = pKa+ logio ([A'] / [HA]) Equation 1In the case of an amine, the free amine is [A‘] and the protonated amine is [HA], A protonated amine is believed to be unavailable for sequestering carbon dioxide. When the concentration of conjugate base equals the acid concentration, the pH is equal to the pKabecause the logio of 1 is 0. Some amines, such as alkanolamines, have pKavalues closer to neutrality than do other amines. Therefore, more free amine is available for sequestering carbon dioxide at lower pH values. For carbon dioxide capture, it is believed that more active sequestration of carbon dioxide may be realized for less basic amines (e.g., amines having apKavalue relatively close to a pH of 7), given that a lower fraction of amine is protonated, thereby resulting in more available free amine for forming a carbamate species. A carbamate form of carbon dioxide may facilitate ready release of the carbon dioxide. In addition, at pH values closer to neutrality, the bicarbonate form of carbon dioxide may be more predominant relative to the carbonate form, which may also facilitate more rapid release of carbon dioxide at a desired time relative to the release rate from the carbonate form. Considerably less hydroxide also forms at lower pH values as well.

[0028] Without being bound by theory or mechanism, the capture and release of carbon dioxide is believed to be facilitated by the pKaof the amine-functionalized polymers. The pKaof carbonate (CO32) is about 9.9 and the pKaof bicarbonate (HCCh ) is about 6.4. As such, any amine with a higher pKawould be expected to exist in equilibrium with carbonate and shift the equilibrium toward carbonate according to Le Chatelier’s principle. Thus, it can be argued that amines with pKavalues greater than carbonate are disadvantageous due to discouraging release of the captured carbon dioxide. In addition, as the pKaof the amines increase, more hydroxide is generated, which is also disadvantageous for energy-efficient thermal or chemical release, since the hydroxide may strongly bond to carbon dioxide as a carbonate species. Since certain amine-functionalized polymers of the present disclosure may have pKavalues that are less than that of carbonate, the equilibrium may be shifted to favor bicarbonate and / or carbamate, which may more easily release captured carbon dioxide at a desired time. Concurrently, and remaining unbound by theory or mechanism, the amine-functionalized polymer may encourage the solubility of carbon dioxide by altering the dielectric constant of water, lowering the surface tension of water, and potentially increasing surface area by controlled foaming. These features may be advantageous regardless of the form of carbon dioxide being sequestered in the water or a similar aqueous fluid since the concentration and mass transfer rate of carbon dioxide may increase in the presence of the amine-functionalized polymer. It is anticipated that other functionalities capable of matching the pKaproperties in this range, regardless of functional group, may function similarly with respect to carbon dioxide binding.

[0029] The amine-functionalized polymers may be in various morphological forms depending on the manner in which the carbon dioxide needs to be captured. The amine- functionalized polymers may be present in the form of particulates (e.g., macroparticulates) or as a coating or layer (polymer layer), either of which may contact a carbon dioxide-containing gas or gas mixture or a carbon dioxide-containing liquid to capture the carbon dioxide therefrom. The particulates or polymer layers may comprise relatively hydrophobic amine-functionalized polymers so that aqueous fluids do not promote dissolution or removal of the particulates or polymer layers. However, the polymer layers may be sufficiently porous to permit free movement of water and gases therethrough. In at least one example, however, amine-functionalized polymers may be rendered water-soluble by choice of the amine functionalization that is present. Such amine-functionalized polymers may be used within a liquid solution or dispersion, including as an aqueous solution, either alone or in combination with other amine-functionalized polymers, to provide additional benefits discussed further herein.

[0030] Moreover, the one or more additional functionalities may be selected such that they undergo reversible chemical modification to promote release of the carbon dioxide in a desired location and at a desired time. The conditions promoting release of the carbon dioxide in the disclosure herein may require considerably less energy input than in current state of the art techniques for capturing and releasing carbon dioxide. Furthermore, once the carbon dioxide has been released, the one or more additional functionalities may be reverted to their original form to again promote capture of additional carbon dioxide. Protonation and deprotonation of the amines may fulfill this role in various examples.

[0031] Thus, the present disclosure provides amine-functionalized polymers, combinations of amine-functionalized polymers, and compositions containing amine- functionalized polymers and small-molecule additives that may be readily “programmed” for promoting sequestration of carbon dioxide (either as a carbamate or a carbonate species) and subsequent release of the carbon dioxide in an energy-efficient manner. Even if the carbon dioxide is not trapped as a sequestered (bound) carbon dioxide species, the amine- functionalized polymers may at the very least promote dissolution of carbon dioxide at a higher concentration than in water alone (in equilibrium with carbonic acid). Ultimately, the form in which the carbon dioxide is sequestered is not critical, as long as the carbon dioxide can be released at a desired time and in an energy-efficient manner. The one or more additional functionalities promoting uptake and release of the carbon dioxide may individually contribute to promoting carbon dioxide uptake and / or release, or multiple additional functionalities may work in cooperation with one another to promote uptake and release. Moreover, the one or more additional functionalities may be selected such that theyundergo reversible chemical modification to promote ready release of the carbon dioxide at a desired location and time, followed by facile reversion to their original form to promote sequestration of additional carbon dioxide. Accordingly, any number (including one or more than one) of the additional functionalities and strategies associated therewith may be utilized in conjunction with promoting carbon dioxide sequestration and release according to the additional description below.

[0032] Suitable amine-functionalized polymers may bear amine-containing side chains. In one example, suitable amine-functionalized polymers may be prepared from polymers bearing electrophilic side chains, particularly oxiranes (epoxides), which have been further reacted with an amine nucleophile. Oxygen, sulfur, phosphorus, selenium or carbon species having a sufficiently nucleophilic lone pair of electrons may also be reacted similarly with the oxirane to promote functionalization according to the disclosure herein, wherein these alterative nucleophiles may introduce an amine tethered to the site of epoxide opening via a spacer group and the nucleophile. Amine nucleophiles, in contrast, may bond the amine either directly at the site of epoxide opening to afford a secondary or tertiary amine or tethered to the site of epoxide opening to afford a primary, secondary, or tertiary amine. Polyamines may also be used to promote epoxide opening, wherein the additional amine groups of the polyamine may undergo further functionalization, as discussed further herein.

[0033] Preferably, the amine-functionalized polymers are obtained by reaction of an amine nucleophile with an epoxide side chain of the polymer. In various examples, the amine-functionalized polymers described herein may be obtained through functionalization of epoxide-containing (meth)acrylic polymers and copolymers with an amine nucleophile under suitable conditions. Suitable (meth)acrylic polymers may include poly(meth)acrylates and poly(meth)acrylamides, a copolymer thereof, or a combination thereof, wherein the (meth)acrylic polymers or copolymers bear an epoxide group. The terms “poly(meth)acrylate” and “poly(meth)acrylamide” encompass any polymer comprising acrylate, methacrylate, acrylamide, and / or methacrylamide monomers, particularly when such monomers are polymerized through their olefinic unsaturation. The term “meth” in parentheses means that a methyl group may or may not be present. If a methyl group is absent, a hydrogen is present in its place.

[0034] More specifically, epoxide-containing (meth)acrylic polymers suitable for undergoing functionalization with an amine nucleophile according to the disclosure hereinmay comprise a glycidyl (meth)acrylate monomer (Compound 1), the corresponding (meth)acrylamide monomer N-(oxiran-2-ylmethyl)(meth)acrylamide (Compound 2), or a copolymer thereof. Variable R is H or a methyl group in both instances.Compound 1 Compound 2

[0035] Optionally, other olefinically unsaturated monomers may also be copolymerized with the foregoing (meth)acrylic monomers, including other (meth)acrylic monomers not bearing an epoxide group. Co-monomers may be included to promote further tailoring of the physical properties of the resulting epoxide-containing (meth)acrylic polymers, including the ability to form crosslinks between adjacent polymer chains, or the amine-functionalized polymers resulting therefrom. In addition, the co-monomers may themselves introduce additional functionalities to promote uptake and release of carbon dioxide according to the disclosure herein or provide a reactive group for introducing such additional functionalities to promote uptake and release of carbon dioxide.

[0036] Other co-monomers that may be copolymerized with the foregoing olefinically unsaturated monomers may include, for example, (meth)acrylic acid, (meth)acrylate esters, (meth)acrylamide, alpha olefins, olefins capable of forming crosslinks between adjacent polymer chains, and the like. Methyl methacrylate and hydroxyethyl methacrylate may be particularly suitable olefinically unsaturated monomers that may be copolymerized with the foregoing. Suitable alpha olefins that may be co-polymerized include, for example, ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene or mixtures thereof. Diene monomers, such as dicyclopentadiene, butadiene, norbornadiene, and similar monomers, may also be copolymerized with any of the foregoing olefinically unsaturated monomers.

[0037] Still other examples of monomers that may be copolymerized with any of the foregoing monomers include, for example, 2-hydroxy ethyl methacrylate (HEMA), 3- (trimethoxysilyl)propyl methacrylate (TSPMA), polyethylene glycol) dimethacrylate (poly- EGMA), diethyleneglycol dimethacrylate, tri-(ethylene glycol) dimethacrylate, 2-acetoacetoxyethyl methacrylate (AAEMA), tris[2-(acryloxy)ethyl] isocyanurate, methyl methacrylate, and zinc methacrylate.

[0038] Illustrative glycidyl methacrylate (GMA) copolymers that may be formed in the disclosure herein include, for example, GMA-HEMA, GMA-TSPMA, GMA-poly- EGMA, GMA-AAEMA, GMA-ASEMA-HEMA, and GMA-AAEMA-TSPMA. Some of these GMA copolymers are configured to undergo crosslinking during and / or after polymerization, either through a crosslinking reaction of their side chains or by incorporating a dangling olefinic unsaturation from a first polymer chain into a second polymer chain as the second polymer chain forms. Any of these GMA copolymers may undergo reaction with an amine nucleophile according to the disclosure herein to form an amine-functionalized polymer that may be exploited in various ways.

[0039] In another specific example, a (meth)acrylic copolymer may be formed from a reaction mixture comprising glycidyl methacrylate, diethyleneglycol dimethacrylate, and tris(2-(acrylolyloxy)ethyl)isocyanurate, wherein the latter two reagents are capable of introducing crosslinks between adjacent polymer chains. Such (meth)acrylic polymers may comprise about 99 wt. % or greater of the glycidyl methacrylate, with the balance of the copolymer being comprised by the two crosslinking agents.

[0040] The epoxide group in the foregoing polymers and copolymers may be functionalized with an amine nucleophile to form various amine-functionalized polymers suitable for use in the disclosure herein. Amine nucleophiles suitable for functionalizing epoxide-containing (meth)acrylic polymers and copolymers in the disclosure herein are not believed to be particularly limited. Non-limiting examples include primary alkyl amines, secondary alkyl amines, polyamines, alkanolamines (e.g., monoalkanolamines and dialkanolamines), and the like. Mixtures of amines, including any combination of primary, secondary, and tertiary amines in a given molecule may also be present. Primary amines may open the epoxide to form a secondary amine at the site of oxidative opening, and secondary amines may open the epoxide to form a tertiary amine at the site of oxidative opening. Some examples of suitable amines may be ligands containing an amine nucleophile, such as, for example, C2-C8 alkylenediamines (e.g., ethylenediamine, 1,3 -propanediamine, 1,4- butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, and the like) or aminopoly carboxylic acids (e.g., iminodiacetic acid, glutamic acid diacetic acid, methylglycine diacetic acid, and the like). Natural or synthetic amino acids may similarlypromote epoxide opening to form an amine-functionalized polymer. In an alternative approach, natural or synthetic amino acids may also be introduced to an amine-functionalized polymer through amidation chemistry, commonly with the amino group of the amino acid in protected form while being reacted with the amine-functionalized polymer. Such ligands may have selectivity for divalent metal ions, particularly alkaline earth metal ions or divalent transition metal ions, or transition metal ions of other valences, wherein the metal-binding capabilities may be retained following epoxide opening and covalent bonding of the ligand to the polymer. In some examples, the metal that is bonded to the ligand may be selected to catalyze the uptake or release of carbon dioxide. Examples include transition metals such as zinc or copper.

[0041] Polyamines, including straight-chain polyamines, branched polyamines, and cyclic polyamines, may also be reacted with the epoxide-containing (meth)acrylic polymers and copolymers to form amine-functionalized polymers suitable for use in the present disclosure. As used herein, the term “polyamine” refers to any compound comprising two or more amine groups, more particularly a diamine, a triamine, a tetraamine, or a pentaamine, any of which may be straight-chain, branched, or cyclic. Particular examples of polyamines that may be suitable for use in the disclosure herein include, for example, diethylenetriamine, triethylenetetraamine, tetraethylenepentaamine, tris(2-aminoethyl)amine, 1,1,1- tris(aminomethyl)methane, 1,1,1 -tri s(aminomethyl)ethane, N,N’- bis(aminoethyl)ethylenediamine, and the like. In another example, a linear or branched polyethyleneimine (polyaziridine) polymer may comprise a polyamine nucleophile that is reacted with the epoxide-containing (meth)acrylic polymer or copolymer.

[0042] In still other examples, an amine nucleophile may be selected to promote solubility of the amine-functionalized polymer in an aqueous fluid. Alkanolamine (amino alcohol) nucleophiles, for instance, may be utilized to promote at least partial solubility or dispersibility of the amine-functionalized polymers in an aqueous fluid. Illustrative examples of suitable alkanolamines may include, but are not limited to, ethanolamine, diethanolamine, N-methylethanolamine, and the like. Other suitable alkanolamines may include, for example, 1,3-propanolamine, l-amino-2-propanol, 2-amino-l -propanol, 2-amino-l,3-propanediol, 3- amino-l,2-propanediol, or any N-alkylated variant of these alkanolamines. As mentioned above, alkanolamines tend to be less basic amines and may facilitate carbon dioxide sequestration in the manner described above. Small-molecule amines may likewise promotepH matching / lower to facilitate advantaged capture and release of carbon dioxide in the manner discussed herein.

[0043] One or more of the amine groups in diamine or polyamine nucleophiles may undergo further functionalization following epoxide opening, such as to introduce an additional functionality effective to promote capture and release of carbon dioxide according to the disclosure herein. Ligands may be further modified before or after epoxide opening for similar reasons as well. Ligands modified through further functionalization may retain their original metal-binding selectivity, or exhibit a different selectivity profile following functionalization. In particular examples, an unreacted amine group from a C2-C8 alkylenediamine or a polyamine (e.g., tris(aminoethyl)amine or N,N’- bis(aminoethyl)ethylenediamine) may undergo further functionalization after a first amine group has reacted with the side-chain epoxide. A ligand may also be constructed in situ by reacting an amine group with a suitable reagent to construct the ligand following opening of the epoxide ring.

[0044] Supramolecular receptors such as crown ethers, porphyrins, cryptands, calixarenes, hexasubstituted benzenes (see U.S. Patent 11,267,773) and the like may similarly be reacted with the epoxide-functionalized polymers via an amine nucleophile or by reacting a complementary functionality upon the supramolecular receptor with an unreacted amine upon the amine-functionalized polymer. Structures of suitable supramolecular receptors will be familiar to one having ordinary skill in the art. Metal ions bound to a supramolecular receptor may similarly aid in promoting carbon dioxide sequestration as discussed herein.

[0045] Accordingly, epoxide-containing (meth)acrylic polymers suitable for undergoing functionalization according to the disclosure herein may be produced from an epoxide-containing (meth)acrylate monomer and have a structure represented by Compound 3 belowCompound 3 wherein x is a positive integer of about 5 or greater (molecular weight may be about 5,000 to about 1,000,000, typically about 10,000 to about 400,000), or about 100 or greater, or about 500 or greater or about 1000 or greater; R is H or methyl, and Z is O, S, Se, NH or PH. Particularly suitable examples of variable Z are O or NH. In more particular embodiments, a suitable (meth)acrylic polymer for undergoing functionalization according to the disclosure herein may be poly(glycidyl methacrylate) (R=Me, Z=O). Although the description herein may be directed primarily to poly(glycidyl methacrylate) polymers and copolymers and functionalization thereof, it is to be appreciated that alternative (meth)acrylic polymers bearing an epoxide group may undergo similar functionalization and find use in various situations. As a particular example, (meth)acrylic polymers and copolymers bearing an N- (oxiran-2-ylmethyl)(meth)acrylamide monomer (Compound 2) may be employed under highly basic conditions that may lead to ester hydrolysis in the corresponding amine- functionalized poly(glycidyl methacrylate) polymers. Introduction of crosslinkable monomers and / or crosslinking of polyamines through the epoxide groups may further tailor the properties of the polymers as well.

[0046] At least a portion of the epoxide groups in the epoxide-containing (meth)acrylic polymer or copolymer may undergo opening with the amine nucleophile when forming the reaction product. The fraction of epoxide groups undergoing opening may be determined by the reaction conditions and the amount of amine nucleophile supplied to the epoxide-containing (meth)acrylic polymer or copolymer, which may be in a first polymerization state prior to being functionalized and in a second polymerization state after being functionalized with the nitrogen nucleophile. After functionalization, the polymer or copolymer comprising the reaction product may have a random distribution of nucleophile-functionalized monomers (obtained by epoxide ring opening) and epoxide-functionalized monomers that have not undergone a ring-opening reaction. The polymer may be further crosslinked in the first polymerization state or while forming the second polymerization state. Compound 4 shows an illustrative formula representing the structure of an amine- functionalized (meth)acrylic polymer after functionalization with an amine nucleophile, specifically poly(glycidyl methacrylate) or a variant thereof functionalized with iminodiacetic acid, wherein the sum of y plus z is greater than or equal to x and the other variables are defined as above. Variable y represents the mole fraction of unfunctionalized (meth)acrylic monomers and variable z represents the mole fraction of functionalized (meth)acrylic monomers. The mole fraction of functionalized (meth)acrylic monomers may range from about 1 mol. % to about 99 mol. %, or about 10 mol. % to about 90 mol. %, or about 20 mol. % to about 50 mol. %. The foregoing ranges are not limited to functionalizations conducted with iminodiacetic acid, and other amine nucleophiles may be incorporated in similar ranges.Compound 4It is to be appreciated that the functionalized poly(glycidyl methacrylate) represented by the structure shown in Compound 4 is illustrative in nature. Other functionalized poly(glycidyl methacrylate) polymers or copolymers prepared via epoxide opening with different amine nucleophiles will have corresponding structures. For example, the structure represented by Compound 5 is the corresponding reaction product formed when poly(glycidyl methacrylate) or the amide analog thereof and ethylenediamine undergo a reaction with one another.Compound 5Polymers having a structure represented by Compound 5 and similar polymers formed by reaction with a polyamine may be further functionalized as described in more detail below. Further crosslinking through epoxide ring opening with the pendant amine group in Compound 5 and similar polyamine-functionalized polymers may occur with any of these polymers in some instances as well.

[0047] Amine-functionalized polymers prepared by opening epoxide groups within a (meth)acrylic polymer or copolymer with a linear polyamine and further functionalizing unreacted amine groups (e.g., with an electrophile) may have a structure represented by Compound 6 belowCompound 6 wherein G is a C2-C8 spacer group and J and J are selected from H or an additional functionality that may promote uptake and release of carbon dioxide, provided that J and J are not both H. J and / or J’ may be introduced by reacting an electrophile with the unreacted primary amine group. Additionally, J and / or J’ may be introduced through use of carbon dioxide as a protecting group. By protecting one or more amines of the polyamine in the foregoing manner, a more reactive unprotected amine may react with the epoxide group. The carbon dioxide protecting groups may then be removed and the resulting free amine may be further functionalized, if desired. By protecting the one or more amines in the foregoing manner, crosslinking between adjacent polymer chains may be avoided. Although not shown, it is to be appreciated that the secondary amine group in Compound 6 (arising from the amine group that opened the epoxide) may also undergo electrophilic functionalization in a similar fashion in certain instances. Particular examples of J and J’ are described further below.

[0048] In more specific embodiments, G is C2-C8 alkylene group, introduced from a C2-C8 alkylenediamine, as shown by the structure represented by Compound 7 belowCompound 7 wherein p is an integer ranging from 2 to 8, and the other variables are defined as above, specifically wherein J and J’ are not both H and the secondary amine may be optionally functionalized with J or J’ in some instances. In particular examples, p may be 2 or 3.

[0049] In some embodiments, the unreacted amine group of a polyamine- functionalized amine-functionalized polymer may be reacted with a phosphorane, specifically an oxazaphospholidine 2-oxide or a phosphorodiamidate, to form a structure represented by Compound 8. G may be a C2-C8 alkylene in particular examples.Compound 8The group bonded to the pendant amine group may serve as a surfactant mimic to facilitate uptake and release of carbon dioxide. In addition, the group bonded to the pendant amine group may promote binding of iron or barium as well. Scheme 1 below shows the manner in which an amine-functionalized polymer may be reacted with a phosphorane to promote sequestration of carbon dioxide according to the disclosure herein. R’ is H or a C1-C30 hydrocarbyl group. If the corresponding poly amine-functionalized polymer is functionalized in a similar manner to that depicted in Scheme 1, a product having a structure corresponding to Compound 8 may be realized. It is to be appreciated that the product structures depicted in Compound 8 and in Scheme 1 may be fluxional with the alcohol group resulting from epoxide opening and / or the alcohol group appended to the phosphoramide nitrogen potentially bonding to the phosphorus center.Scheme 1

[0050] The phosphorane reagent in Scheme 1 and similar analogues may be conveniently prepared by reacting a phosphorus oxyhalide with an amino alcohol, preferably in the presence of a tertiary amine base, such as tri ethylamine. Suitable phosphorus oxyhalides may include, for example, phosphorus oxychloride, phosphorus oxybromide, or any combination thereof. Suitable amino alcohols may include any alkanolamine or N- alkylalkanolamine, such as ethanolamine, 1,3 -propanolamine, l-amino-2-propanol, 2-amino- 1 -propanol, or any N-alkylated variant of these alkanolamines. Suitable N-alkyl substitutions for N-alkylated variants may include, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, isopentyl, hexyl, isohexyl, and the like. Cycloalkyl groups, such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, substituted variants thereof, and the like, are also encompassed by the term alkyl and may suitably substitute the amine group of the phosphorane reagent as well. The phosphorane reagent may have a trigonal bipyramidal geometry or distorted variant thereof and exist as a plurality of axial and equatorial isomers in equilibrium between open- and closed-chain forms, as illustrated in Scheme 1. Such phosphorane reagents may exhibit electrophilic reactivity toward alcohols, phenols, and primary or secondary amines, thereby affording multiple routes for a reaction to occur.

[0051] Other types of functional groups may also be reacted with the amine to introduce a group that is sufficiently amphiphilic to provide surfactancy. Illustrative examples may include phosphates, amphoteric compounds having a head group similar tothat of phosphatidylcholine, carboxylates, boronates, sulfates, sulfonates, selenides, selenates, and the like. In another example, amine-functionalized polymers bearing tethered ammonium phosphates or ammonium sulfates may function simultaneously to provide surfactancy and alter the dielectric constant of an aqueous fluid in a desired manner. Lecithin may also be combined with the amine-functionalized polymers described herein as a smallmolecule additive to provide surfactancy. Other conventional cationic, anionic, zwitterionic, or neutral surfactants may also be used, if desired.

[0052] In some embodiments, the unreacted amine group of a polyamine- functionalized amine-functionalized polymer may be reacted with a sultone to form a structure represented by Compound 9. G may be a C2-C8 alkylene in particularCompound 9 examples. In Compound 9, R is H, an alkyl group (e.g., a C1-C12 alkyl group) or (CH2)nCH2CH2SO3H, and n is an integer ranging from 0 to 2, preferably 1 or 2. The sulfonic acid group tethered to the pendant amine group may serve as a surfactant mimic to facilitate uptake and release of carbon dioxide. In addition, the sulfonic acid group tethered to thependant amine group may promote binding of barium ions as well. Scheme 2 below shows the manner in which an amine-functionalized polymer may be reacted with a sultone to promote sequestration of carbon dioxide according to the disclosure herein. R’ is H or a Ci- C30 hydrocarbyl group. If the corresponding polyamine-functionalized polymer is functionalized in a similar manner to that depicted in Scheme 2, a product having a structure corresponding to Compound 9 may be realized.

[0053] In non-limiting examples, suitable sultone reagents used in Scheme 2 may be prepared by cyclization of haloalkanesulfonic acids, hydroxyalkanesulfonic acids, sulfonation of alkenes with sulfur trioxide, or other methods familiar to persons having ordinary skill in the art. 1,3-propanesultone, for example, may be synthesized by reacting allyl alcohol with sodium bisulfite under acid-catalyzed conditions.

[0054] Another compound suitable for binding iron may be obtained by reacting a polyamine-functionalized polymer with a catechol or catechol derivative bearing a carboxylic acid to afford an amide bond. In particular, the phenolic hydroxyl groups upon the catechol may be protected as acetate esters, for example, or another suitable protecting group while reacting with the carboxylic acid with the amine to form the amide bond. The acetate esters or other protecting group may be removed following formation of the amide bond to liberate the free catechol. Alternately, the acetate esters or alternative protecting groups may undergo in situ removal when bonding a metal ion. An illustrative amine-functionalized polymerbearing a pendant catechol may have a structure represented by Compound 10 below. It is to be appreciated that the phenolic hydroxyl groups need not necessarily be located at the 2 and 3 positions of the aromatic ring and may also be suitably located at the 3 and 4 positions. Moreover, additional phenolic hydroxyl groups and / or optional functionality may be present upon the aromatic ring.Compound 10

[0055] Other phenolic compounds may be coupled to an amine-functionalized polymer in a similar fashion. Compound 11 is representative of the structure of an amine- functionalized polymer containing a tethered phenol.In Compound 11, the phenol may be located at any position of the aromatic ring, and Q represents optional functionality that may be present upon the aromatic ring. The position of the phenol and the presence of optional functionality may tailor the acidity of the phenol, which may, in turn, determine the extent to which the phenol deprotonates at a given temperature. For example, electron-withdrawing groups (e.g., nitro or halogen) may increase the acidity of the phenol, and electron-donating groups (e.g., alkoxy or alkyl) may decrease the acidity of the phenol. Thus, the particular phenol structure may be selected to such that the phenol deprotonates at a desired temperature to promote release of carbon dioxide at a desired temperature.

[0056] Alternately, an aminophenol may be utilized for introducing an amine-linked phenol to the epoxide-containing (meth)acrylic polymer or copolymer, wherein the amine directly promotes opening of the epoxide. The amine may be an aromatic amine or an aliphatic amine linked to the aromatic ring of the phenol by a spacer group. Illustrativephenol-containing amine-functionalized polymers in accordance with the foregoing may have structures represented by Compounds 12A and 12B below.Variables Q, Z, y, and z are defined as above. Variable L is an aliphatic space group, such as a C1-C4 alkylene group, for example. In some examples, L may be a methylene group.

[0057] Another approach for introducing a phenol to the epoxide-containing (meth)acrylic polymer or copolymer may involve utilizing one phenol group of a catechol as a nucleophile to promote opening of at least a portion of the epoxide groups in the epoxide- containing (meth)acrylic polymer or copolymer. The phenol may be present alone upon the resulting functionalized (meth)acrylic polymer or copolymer, or present in combination with one or more amine groups if both a phenol nucleophile and an amine nucleophile are utilized to promote epoxide opening. Alternately, a phenol-functionalized (meth)acrylic polymer or copolymer may be utilized in combination with an amine-functionalized polymer or copolymer described above. An illustrative phenol-functionalized polymer obtained by nucleophilic opening of a side-chain epoxide with a catechol may have a structure represented by Compound 13 below.Variables Q, Z, y, and z are defined as above. Again, electron-withdrawing groups or electron-donating groups may alter the acidity of the phenol as needed.

[0058] Still another compound that may exhibit surfactancy or pH-modifying effects may be obtained by reacting 2-methylthioimidazoline with an amine group of a polyamine.Compound 14 is representative of the types of structures that may be obtained. The amidate group of Compound 14 may bind sulfate anions, and a similar effect may be realized with carbonate or bicarbonate ions in some cases.Compound 14

[0059] Additional amine-functionalized polymers having further amphiphilic functionalization sufficient to provide surfactancy may be produced as well. Compound 15 below has a zwitterionic head group inspired by that present in phosphatidylcholine. This compound may be produced by reacting poly(glycidyl methacrylate) with the mono- phosphoramidate of ethylenediamine and then quatemizing the resulting secondary amine with an alkylating agent. Other synthetic approaches for synthesizing such polymers may also be envisioned.Compound 15

[0060] Phosphonate-functionalized amine-functionalized polymers are another type of amine-functionalized polymer that may provide surfactancy in the disclosure herein. Phosphonate functionalization may take place by further reacting an electrophilic brominated phosphonate diester (e.g., 2-bromoethylphosphonate diethyl ester) with an amine- functionalized polymer, followed by removal of the alcohol component of the phosphonate esters to reveal the corresponding phosphonic acid. Any of the amine-functionalized polymers described herein may undergo such further functionalization to introduce a phosphonate. Phosphonate functionalization may therefore be present in combination with any of the additional functionalities described herein.

[0061] Quaternary ammonium-functionalized amine-functionalized polymers are another type of amine-functionalized polymer that may provide surfactancy in the disclosure herein. In non-limiting examples, introduction of a quaternized nitrogen atom may take place by reacting aminocholine with poly(glycidyl methacrylate). Other synthetic approaches for synthesizing such polymers may also be envisioned.

[0062] Again, it is to be appreciated that functionalization of the secondary amine in any of Compounds 6-15, although not shown, may occur in conjunction with functionalization of the primary amine. In addition, the primary amine may be functionalized with multiple occurrences of the functionalizing species in some instances. Moreover, Compounds 6-15 show structures derived from a single primary amine. It is to be appreciated that precursors having two or more primary amine groups may be prepared similarly and undergo functionalization in accordance with the disclosure above. Compound 16 below shows a representative structure having two primary amines, formed by reacting a dendritic polyamine, such as tris(aminoethyl)amine, with the epoxide-containing (meth)acrylic polymer or copolymer.The primary amine groups or a portion thereof may be further functionalized to introduce an additional functionality that may promote sequestration and release of carbon dioxide, such as the particular examples discussed above.

[0063] In at least some examples, such as when an alkanolamine is used for epoxide opening, the amine-functionalized polymers may be soluble in aqueous fluids. As such, another suitable morphological form for the amine-functionalized polymers in the disclosure herein is an aqueous solution or dispersion of the amine-functionalized polymer. Such water- soluble amine-functionalized polymers may be effective for carbon dioxide sequestrationalone or utilized in combination with solid-form amine-functionalized polymers, such as macroparticulates or polymer layers, to cooperatively promote carbon dioxide capture and release as well. Compounds 17A and 17B below show representative structures formed by reacting an alkanolamine (diethanolamine or ethanolamine, respectively,) with the epoxide- containing (meth)acrylic polymer or copolymer.Compound 17B

[0064] The amine-functionalized polymers may be in various morphological forms to promote capturing of carbon dioxide according to the disclosure herein. In non-limiting examples, the amine-functionalized polymers may be in the form of macroparticulates, coatings or layers (collectively referred to as polymer layers), or the like. The term “macroparticulate” refers to any particulate material having an average size of about 1 mm or more, or about 5 mm or more, or about 10 mm or more in size. Macroparticulates may represent a readily handled form of the amine-functionalized polymers. Polymer layers containing the amine-functionalized polymers may be particularly suitable for flow-through applications for capturing carbon dioxide, either from a gas or gas mixture containing carbon dioxide or from a carbon dioxide-containing fluid. Macroparticulates may likewise be utilized in flow-through applications, such as when constrained within a cartridge, bag, or similar container. Additional description of suitable macroparticulates and how the amine- functionalized polymers may be formed and manipulated to form macroparticulates, or coatings or layers is provided hereinafter.

[0065] Glycidyl methacrylate (Compound 1) and similar (meth)acrylic monomers bearing a side chain epoxide group may be polymerized and rendered into a form suitable for undergoing further functionalization with an amine nucleophile according to the disclosure herein. Depending on the manipulations taking place, the further functionalization may result in formation of a macroparticulate, a polymer layer, or a polymer solution, any of which may be utilized in conjunction with capturing carbon dioxide, as described further below. In each case, glycidyl methacrylate or a similar (meth)acrylic monomer may be polymerized to a first polymerization state (e.g., through a living polymerization reaction or a free radical polymerization reaction) that is a solid polymer product capable of being further manipulated. For example, the solid polymer product may be isolated and rendered into a predetermined shape or a surface layer suitable for undergoing further functionalization. Other polymerization techniques may also be suitable to achieve the first polymerization state. The solid polymer product in the first polymerization state may be crosslinked during the living polymerization reaction, or the polymer may be further crosslinked with a crosslinking agent thereafter, particularly during functionalization with the nitrogen nucleophile or after functionalization with the nitrogen nucleophile has taken place. Specifically, the polymer isolated in the first polymerization state may be rendered into the form of a dense bodyhaving a predetermined shape, such as a disk, sphere, extrudate, coating, or similar structure. The structure obtained after rendering the polymer into a desired shape in the first polymerization state is solid, although some minor voids may be present depending on manufacturing or processing inconsistencies. Advantageously, the predetermined shape provided at this juncture may be varied according to particular process needs, such that a range of macroparticulate structures of any desired size may be produced once further functionalization with an amine nucleophile has taken place. Advantageously, a profile of the predetermined shape rendered at the pre-functionalization stage may be largely maintained following functionalization with an amine nucleophile, except volume expansion and a corresponding decrease in the density may occur in some instances. That is, functionalization with an amine nucleophile may promote an increase in size and / or other morphological changes of the pre-functionalization shape to afford an increased size and decreased density, while still maintaining the overall appearance of the predetermined shape following functionalization. An internal cavity may form within the macroparticulates under some functionalization conditions. Spherical pre-functionalization shapes may be formed by rolling the (meth)acrylic polymer or copolymer in the first polymerization state into a substantially spherical shape before undergoing further functionalization. Polymer layers may be formed by casting the (meth)acrylic polymer or copolymer onto a surface or evaporating a solution of the (meth)acrylic polymer or copolymer onto a surface, either before or after functionalization with the amine nucleophile takes place.

[0066] Suitable techniques for forming a polymer layer may comprise dissolving or emulsifying the amine-functionalized polymer (e.g., an amine-functionalized (meth)acrylic polymer or copolymer) in a solvent to provide a coating formulation, and applying the coating formulation to a substrate. Alternately, the amine-functionalized polymer may be directly molded, cast, or extruded, for example, to provide a surface layer without depositing the polymer on a base substrate. When used, suitable base substrates may include, but are not limited to, other polymers, ceramics, wood, metals, glass, and the like.

[0100] When disposed as a polymer layer, the amine-functionalized (meth)acrylic polymers may have a layer thickness of about 100 nm or greater, particularly about 1 micron or greater. Optionally, an article comprising a polymer layer may be formed substantially from the amine-functionalized, in which case the polymer layer thickness may be much greater. Articles comprising a polymer layer of the present disclosure may include, but arenot limited to, those in which inline sequestration of carbon dioxide may be desirable, such as within a pipeline, engine, tower, or the like.

[0067] Free radical polymerization, solution polymerization, suspension polymerization, or emulsion polymerization may also be suitable for forming epoxide- containing (meth)acrylic polymers or copolymers in the first polymerization state. Such epoxide-containing (meth)acrylic polymers or copolymers may similarly be formed into a predetermined shape and undergo functionalization with an amine nucleophile according to the disclosure herein. Suitable conditions for conducting such alternative polymerization techniques will be familiar to one having ordinary skill in the art.

[0068] In a non-limiting embodiment, poly(glycidyl methacrylate) and similar epoxide-containing (meth)acrylic polymers and copolymers suitable for use in the disclosure herein may be obtained by living polymerization, which affords a dangling reactive intermediate upon a terminus of the polymer chain. Suitable living polymerization conditions for (meth)acrylic monomers may include Cu(I) mediation in the presence of a suitable radical initiator, such as AIBN or ethyl 2-bromo-2-methylpropanoate. It is also to be appreciated that suitable Cu(I) active species may be produced in situ by oxidation or reduction of Cu(0) or Cu(II) respectively. If left unquenched, the dangling reactive intermediate may undergo further polymerization when exposed to more olefinic monomer or another entity suitable for reacting with the reactive intermediate. In living-polymerized poly(glycidyl methacrylate) and similar (meth)acrylic polymers or copolymers, the dangling reactive intermediate may undergo further polymerization when functionalizing the polymer initially obtained in a first polymerization state (pre-functionalization), thereby affording a second polymerization state after functionalization with the amine nucleophile has taken place. That is, poly(glycidyl methacrylate) or similar (meth)acrylic polymers and copolymers obtained by living polymerization may undergo additional polymerization (e.g., between two dangling reactive intermediates or unpolymerized (meth)acrylic monomers) when undergoing further functionalization with an amine nucleophile according to the disclosure herein. Postfunctionalization curing by heating or UV light exposure may also be performed. Dangling reactive intermediates may lead to crosslinking between adjacent polymer chains as well. Crosslinking occurring through polyamine nucleophiles may also take place, such as by reacting an epoxide from a first polymer chain with an amine group of a polyamine upon a second polymer chain. As such, the poly(glycidyl methacrylate) or similar (meth)acrylicpolymers and copolymers may be polymerized to the first polymerization state, where the polymer may still be easily manipulated into a desired, predetermined shape, and then undergo further curing before, concurrently with, or after being further functionalized with an amine nucleophile according to the disclosure herein. Optionally, small-molecule additives for promoting capturing of carbon dioxide may be blended with the polymer in the first polymerization state. The second polymerization state formed during curing or functionalization may represent a higher molecular weight than does that of the first polymerization state. Although living polymerization may be advantageous for practicing the disclosure herein, it is to be appreciated that epoxide-containing poly(glycidyl methacrylate) and similar (meth)acrylic polymers and copolymers obtained through other radical polymerization techniques may also be suitable for use in the disclosure herein.

[0069] In a specific example, glycidyl methacrylate may be polymerized under living polymerization conditions in the presence of a catalytic amount of copper (I) bromide, a catalytic amount of N-(pyridine-2-ylmethylene)butan-l -amine (ligand for Cu(I)), and a catalytic amount of azobisisobutyronitrile (AIBN). A second polymerization state may be reached while or after forming the reaction product.

[0070] It is to be appreciated that at least some of the amine-functionalized polymers described herein may be formed in an alternative manner. In the above description, an epoxide-containing polymer or copolymer is first formed and then reacted with an amine nucleophile to form an amine-functionalized polymer, wherein a free amine within the amine-functionalized polymer may then be further functionalized. Alternately, an appropriate epoxide-containing monomer may first be functionalized with an amine nucleophile to form an amine-functionalized monomer, which may then undergo polymerization and subsequent further functionalization. Scheme 3 below shows such an alternative approach for forming polymers functionalized with an alkanolamine (residual epoxide groups and / or co-monomers, if present, are not shown).Scheme 3

[0071] In some examples, the amine-functionalized polymers may be present in the form of a macroparticulate. The macroparticulates may provide a significant quantity of amines upon the surface and within the interior of the macroparticulates to promote sequestration of carbon dioxide in a desired form. Additional functionalities configured to promote carbon dioxide sequestration in a desired way may be introduced to the macroparticulates or other morphological form of the amine-functionalized polymers, either by reacting with an amine tethered to the site of epoxide opening, an amine at the site of epoxide opening, with a hydroxyl group at the site of epoxide opening, or through reaction with residual epoxide groups in the amine-functionalized polymer. Similarly, surfaces containing the amine-functionalized polymers may undergo functionalization for use in a similar manner. Small-molecule additives for promoting carbon dioxide sequestration may be blended with an epoxide-containing (meth)acrylic polymer or copolymer that is subsequently processed to form a macroparticulate or polymer coating, or the small-molecule additives may be introduced within the polymer matrix after amine functionalization has taken place.

[0072] Spherical macroparticulates may be particularly advantageous to afford high packing efficiencies for confining large quantities of macroparticulates into a small treatmentvolume. For example, spherical macroparticulates may afford high packing densities in cartridges or filter pods suitable for use in the methods and systems disclosed herein, as discussed further hereinbelow. Although the macroparticulates may be advantageously substantially spherical, it is to be appreciated that they may possess microscopic surface roughness, and moreover, macroparticulates having any shape may be used for promoting capture and release of carbon dioxide according to the disclosure herein. Advantageously, the relatively large size of the macroparticulates used herein may facilitate a rather high degree of porosity in a packed bed, thereby providing relatively little flow resistance for sequestration of carbon dioxide from gaseous or fluid streams.

[0073] To form macroparticulates or a related morphological form of the amine- functionalized polymers, an epoxide-containing polymer may be optionally blended with one or more small-molecule additives and formed into a predetermined shape or deposited as a polymer layer. Following reaction with an amine nucleophile, the predetermined shape may be maintained. Small-molecule additives may introduce additional functionalities that may promote capture and release of carbon dioxide, such as a pH-modifying moiety (including acid groups, basic groups, a buffering moiety, or salts thereof), an amphiphilic (surfactant) moiety, and / or metal ions.

[0074] In non-limiting examples, small-molecule additives may contribute additional functionality to an amine-functionalized polymer, rather than the additional functionalities being covalently bonded to the polymer. For example, a surfactant, a metal ion catalyst, a chelating agent, and a buffer and dielectric modifier may be combined to promote capture and release of carbon dioxide. In at least one example, the surfactant may be phosphatidyl choline or other phospholipids found in lecithin, the metal ion catalyst may be zinc, the chelating agent may be tris(2-aminoethyl)amine, and the buffer and dielectric modifier may be triethanolamine. Compositions such as these may reversibly bind and release carbon dioxide at a pH of about 8.

[0075] The reaction of the epoxide-containing polymer or copolymer may take place in the presence of a suitable base. Suitable bases for reacting the amine nucleophile with the epoxide group may include tertiary amine bases, such as but not limited to, trimethylamine, triethylamine, N,N-diisopropylethylamine (Hiinig’s base), 2,2,6,6-tetramethylpiperidine, 1,8- diazabicyclo[5.4.0]undec-7-ene (DBU), l,5-diazabicyclo[4.3.0]non-5-ene (DBN), 4- dimethylaminopyridine (DMAP) and the like. When the epoxide opening is conducted in thepresence of suitable tertiary amine bases, the polymer may undergo a morphological change in some cases. During functionalization with an amine nucleophile, a macroparticulate having a predetermined shape may undergo expansion to afford a larger macroparticulate volume. Under certain reaction conditions, a hollow cavity may result in the interior of macroparticulates, for example. Predetermined shapes such as solid disks, tubes, or spheres may undergo functionalization according to the disclosure herein, optionally with expansion and morphological changes, to afford a reaction product having a specified internal structure formed by self-assembly. Polymer layers may undergo expansion as well.

[0076] FIGS. 1 A and IB show diagrams of a macroparticulate before and after functionalization with an amine nucleophile, respectively. FIG. 1 A shows macroparticulate 100 having diameter D before undergoing functionalization and expansion. FIG. IB shows macroparticulate 101 formed from macroparticulate 100 according to the disclosure herein. As shown, macroparticulate 101 has an expanded diameter D’ and internal cavity 104 has formed therein. Depending on the reaction conditions, internal cavity 104 may or may not form.

[0077] Macroparticulates produced according to the disclosure herein may be formed from a pre-functionalization, extruded shape having a diameter of about 1.5 mm to about 2.5 mm, typically about 2.25 mm. Spherical post-functionalization shapes formed from such extrudates (after rolling in a pre-functionalization spherical shape) may have an effective diameter ranging from about 5.5 mm to about 11 mm, or about 6.2 mm to about 8.6 mm, or about 6.2 mm to about 10.5 mm, or about 6 mm to about 6.5 mm, or about 6.5 mm to about 7.0 mm, or about 7.0 mm to about 7.5 mm, or about 7.5 mm to about 8.0 mm, or about 8.0 mm to about 8.5 mm, or about 8.5 mm to about 9.0 mm, or about 9.0 mm to about 9.5 mm, or about 9.5 mm to about 10.0 mm, or about 10.0 mm to about 10.5 mm, or about 10.5 mm to about 11.0 mm. Depending on shape, non-spherical shapes may have effective diameters (cross-sectional dimensions) ranging from about 5.0 mm to about 11.5 mm, or about 5.0 mm to about 6.0 mm, or about 6.0 mm to about 7.0 mm, or about 7.0 mm to about 8.0 mm, or about 8.0 mm to about 9.0 mm, or about 9.0 mm to about 10.0 mm, or about 10.0 mm to about 11.0 mm.

[0078] Crosslinking of the poly(glycidyl methacrylate) or similar (meth)acrylic polymers and copolymers may occur in conjunction with forming the macroparticulates in the second polymerization state, or crosslinking may occur after the macroparticulates in thesecond polymerization state have been formed. Still further alternately, crosslinking may occur in the course of forming the first polymerization state, with nucleophilic functionalization of the crosslinked (meth)acrylic polymer or copolymer resulting in formation of the second polymerization state.

[0079] The amine-functionalized polymers of the present disclosure may provide a large contact area for promoting capture of carbon dioxide, either in the form of macroparticulates, a polymer layer, or similar construct, any of which may be disposed within a continuous flow line from which carbon dioxide may be collected. Macroparticulates may be particularly advantageous in this regard since they may be readily removed and replaced to provide continuous sequestration of carbon dioxide. To promote ready removability, the macroparticulates may be housed in a suitable cartridge or similar storage medium, such as a filter pod.

[0080] Once the amine-functionalized polymer has become laden with carbon dioxide, the carbon dioxide may be decomplexed from the polymer, optionally after removing the polymer from the source of carbon dioxide undergoing treatment according to the disclosure herein. Environmental conditions may be changed to promote release of the carbon dioxide in an energy-efficient manner. For example, a less favorable binding environment for carbon dioxide may be created, thereby facilitating release of carbon dioxide from the amine-functionalized polymer. In one example, the temperature of the amine- functionalized polymer may be increased to promote deprotonation of a phenol or other proton ionizable group to change the local pH environment for promoting release of carbon dioxide. The deprotonation may occur at different pH values depending on the pKaof the phenol that is present. An acid or base may similarly be added to the amine-functionalized polymer to promote release of carbon dioxide at a desired time. In another example, a metal ion may be removed from the amine-functionalized polymer and / or the metal ion may undergo complexation in a different manner to make carbon dioxide binding less favorable. Once no longer laden with carbon dioxide, the amine-functionalized polymers may be reused for conducting further sequestration of carbon dioxide.

[0081] Release of carbon dioxide from the amine-functionalized polymer may be conducted under static conditions or under continuous flow conditions. Static release of carbon dioxide from the amine-functionalized polymer laden with carbon dioxide may be conducted by heating the amine-functionalized polymer or contacting amine-functionalizedpolymer with a reagent for a period of time and collecting carbon dioxide as it is liberated. The period of time may vary depending upon the extent of release needed, the type of reagent or temperature being employed, and the like. More desirably, carbon dioxide may be removed by subjecting the amine-functionalized polymer to a flow condition suitable to promote release of the carbon dioxide, such as an inert gas heated above a threshold temperature for promoting release of the carbon dioxide. In other examples, a steam flow may be utilized to promote release of the carbon dioxide. As the steam flow transfers heat to the amine-functionalized polymer, the carbon dioxide may be released and the steam may condense to water. A gas providing the flow condition may carry the released carbon dioxide away from the amine-functionalized polymer so that further sequestration of carbon dioxide can subsequently occur. In another example, pellets may be heated without a carrier gas. As the CO2 is released, the gas maybe released through a check valve into a compressible chamber for later delivery of a concentrated stream.

[0082] Continuous sequestration of carbon dioxide may take place by exposing macroparticulates (e.g., in a bed or cartridge) or a polymer layer to a fluid containing carbon dioxide. Cartridges may come in many forms and include any structure capable of containing the macroparticulates over a time during which the macroparticulates are in contact with the fluid. As non-limiting examples, cartridges may be made of a rigid material, such as plastic, that is machined or molded to allow fluid access to the interior of the cartridge, or paper or cloth socks, bags, or the like may be used to contain the macroparticulates. Cartridges of any type may be refillable or disposable. The fluid containing carbon dioxide, such as combustion exhaust or natural gas, may be flowed through the bed or cartridge(s) of macroparticulates multiple times until a desired carbon dioxide level is reached and / or until the amine-functionalized polymer becomes saturated with carbon dioxide. The fluid containing carbon dioxide may be circulated through the amine-functionalized polymer in some cases, if desired. Although such flow-through processes may be advantageous, particularly for treating large fluid volumes, it is to be appreciated that the separation principles described herein may be applicable to batch-type processes as well.

[0083] The absorption efficiency of this material is unexpected. Due to the nature of the construction, the materials also adsorb neutral hydrocarbons such as natural gas and related products. Like carbon dioxide, other reactive gases can be captured, then reversibly release in a concentrated stream. These include water vapor, ammonia, hydrogen sulfide andsulfur dioxide. In general for remediation purposes, the ability to customize the surface to match the target, a stream of vapor, or gas including mixtures of organic compounds such as carboxylic acids, carboxylic acid derivatives, acid chlorides, amines, amides, anhydrides, ethers and organic suflides, organic selenides, phosphorous containing organics is also contemplated. This could also include mixed streams of water, water vapor, liquid hydrocarbons, gaseous hydrocarbons and could include reactive gases like NH3, SO2 and H2S. Further, such an application could include preprocessing a natural gas stream to remove unwanted contaminants that could lower the heating value of the incoming stream. Alternatively, this could treat the product mixture output from an combustion process.

[0084] To facilitate continuous separation processes, a first portion of amine- functionalized polymer may be placed in contact with a gas stream or fluid in need of removal of carbon dioxide therefrom, and a second portion of amine-functionalized polymer may be placed in latent fluid communication with the gas stream or fluid. Once the first portion becomes saturated or laden with carbon dioxide, the second portion may be placed in fluid communication with the gas stream fluid and the first portion may be separated and regenerated. Such latent fluid communication may be readily achieved when macroparticulates are housed in one or more removable cartridges that are disposed within or in latent fluid communication with the continuous flow. Suitable configurations for achieving such latent fluid communication are described further below. While the description below is directed to configurations for placing macroparticulates in latent fluid communication with a continuous flow, it is to be appreciated that polymer layers containing the compositions of the present disclosure may be configured similarly.

[0085] Remediation systems of the present disclosure incorporating the concepts described hereinabove may include those capable of continuously processing a fluid containing carbon dioxide. Particular implementations of the remediation systems may comprise: a continuous flow line configured to receive a substance in need of contaminant remediation (e.g., a fluid containing carbon dioxide); a composition containing an amine- functionalized polymer, such as a plurality of macroparticulates of the present disclosure, located within the continuous flow line; and optionally, at least one detector configured to interrogate the substance in need of contaminant remediation and / or the amine-functionalized polymer within the continuous flow line. In some embodiments, the remediation systemsmay further comprise a first interrogation zone upstream of the amine-functionalized polymer; and a second interrogation zone downstream of the amine-functionalized polymer.

[0086] The amine-functionalized polymer may comprise a plurality of macroparticulates, which may be housed in one or more removable cartridges when disposed within the continuous flow line. Accordingly, particular remediation systems of the present disclosure may comprise: a continuous flow line configured to receive a substance in need of contaminant remediation; one or more removable cartridges disposed within the continuous flow line, the one or more removable cartridges containing a plurality of macroparticulates; and a detector configured to interrogate the substance in need of contaminant remediation and / or the plurality of macroparticulates within the continuous flow line. The remediation systems may further comprise a first contaminant interrogation zone upstream of the one or more removable cartridges; and a second contaminant interrogation zone downstream of the one or more removable cartridges. One or more detectors may be configured for interrogating the substance in each contaminant interrogation zone. The one or more cartridges may be removable without disrupting a flow of the substance in need of contaminant remediation through the continuous flow line. In further particular embodiments, contaminant-laden amine-functionalized polymer not within the continuous flow, but in latent fluid communication therewith, may themselves be exposed to conditions suitable to promote decomplexation or removal of a contaminant (e.g., carbon dioxide) from the amine-functionalized polymer. Thus, particular embodiments may employ at least a first portion of amine-functionalized polymer located within a continuous flow containing at least one contaminant, and a second portion of amine-functionalized polymer in latent fluid communication with the continuous flow containing the at least one contaminant, wherein the second portion of amine-functionalized polymer in latent fluid communication with the continuous flow is exposed to conditions suitable for promoting removal of carbon dioxide. The contaminant may comprise carbon dioxide in the disclosure herein.

[0087] Alternative remediation systems of the present disclosure may incorporate macroparticulates that are not housed in a removable cartridge. The remediation systems may circulate a substance in need of contaminant remediation through a packed bed of the macroparticulates (e.g., in a filter pod) or freely circulate the macroparticulates within a continuous flow line to promote removal of carbon dioxide from a fluid. When free macroparticulates become saturated with carbon dioxide, the macroparticulates may beremoved for decomplexation of carbon dioxide therefrom. Swing bed configurations for free macroparticulates in a packed bed within a continuous flow line, similar to those discussed below for macroparticulates housed in a removable cartridge, may be employed to allow continuous processing of a substance to take place for promoting removal of carbon dioxide therefrom. Accordingly, such remediation systems may comprise a continuous flow line configured to receive a substance in need of carbon dioxide removal; one or more amine- functionalized polymers (such as in the form of macroparticulates) disposed within the continuous flow line, in sequence and / or parallel; and optionally, a detector configured to interrogate the substance in need of carbon dioxide removal and / or the amine-functionalized polymer within the continuous flow line. The amine-functionalized polymer may be in the form of a packed bed of macroparticulates or the macroparticulates may freely circulate in the continuous flow line. The systems are operable to promote removal of carbon dioxide in the continuous flow line without disrupting a flow through the continuous flow line. Polymer layers containing the amine-functionalized polymers may be similarly configured.

[0088] The remediation systems of the present disclosure may employ a plurality of removable cartridges, which may comprise two or more cartridges configured to sequester a particular contaminant of interest. When two or more cartridges containing macroparticulates of a particular type are present in the remediation systems, at least one of the two or more cartridges may be disposed in the continuous flow line and at least one of the two or more cartridges may be in latent fluid communication with the continuous flow line. Particular configurations may include those in which the two or more cartridges are disposed in a swing bed configuration within the continuous flow line or the two or more cartridges are arranged upon a movable assembly in fluid communication with the continuous flow line. Movable assemblies may include those capable of moving linearly, rotationally, or in a loop. Further disclosure is provided hereinafter in reference to the drawings. By maintaining at least one cartridge in latent fluid communication with the continuous flow line, processing of the substance in need of carbon dioxide removal may take place continuously without disrupting flow while replacing a cartridge that has become laden with carbon dioxide and the amine- functionalized polymer therein needs to be regenerated. Polymer layers containing the amine-functionalized polymers may be similarly configured.

[0089] FIG. 2A shows a diagram of a remediation system of the present disclosure in which multiple cartridges are arranged in a swing bed configuration. As shown, remediationsystem 200 includes continuous flow line 202 having inlet end 204 and outlet end 206. A substance in need of carbon dioxide removal enters continuous flow line 202 through inlet end 204 and proceeds to optional contaminant interrogation zone 210, in which the substance may be spectrophotometrically assayed using spectrophotometer 212. It is to be appreciated that non-spectrophotometric assays may also take place within optional contaminant interrogation zone 210, such as pH measurement or electrochemical assays, for example. In non-limiting examples, spectrophotometric assays may take place using appropriate dyes for UV / Vis, fluorescence, and luminescence detection. All or part of a bed comprising the amine-functionalized polymers may be doped with the dye so that an operator knows when to change the bed and / or when the conditions associated with capturing carbon dioxide have changed. This enables real-time monitoring of the chemical process to aid efficient operation.

[0090] After optionally being assayed in contaminant interrogation zone 210, the substance then proceeds to remediation section 218, which includes one or more amine- functionalized polymers and optional small-molecules configured for sequestering and subsequently releasing carbon dioxide. In the configuration shown in FIG. 2A, the amine- functionalized polymer is housed in two removable cartridges 220a and 220b that are arranged in a swing bed configuration. In a swing bed configuration, only one of removable cartridges 220a and 220b have substance flowing therethrough at a given point in time. For example, substance may be flowing through removable cartridge 220a, and line 230 may be shut off to preclude flow through removable cartridge 220b. Though not shown, a continuous flow of a reagent suitable for promoting carbon dioxide decomplexation may be flowed through removable cartridge 220b in preparation for return thereof to continuous flow line 202. Although a swing bed configuration may be desirable to allow uninterrupted flow through continuous flow line 202, it is to be appreciated that removable cartridges 220a and 220b may also be operated in parallel in some instances. Further, polymer layers containing the amine-functionalized polymers may be similarly configured.

[0091] Optionally, the condition of the amine-functionalized polymer in removable cartridge 220a or 220b may be monitored using spectrophotometer 222a or 222b, respectively.

[0092] When the amine-functionalized polymer in removable cartridge 220a has become saturated with carbon dioxide, system 200 may automatically divert the continuousflow through branch line 230 to removable cartridge 220b. Manual diversion of the continuous flow may also take place in some cases. Upon being remediated in removable cartridge 220b, the remediated substance may return to continuous flow line 210 for further analysis, as described hereinafter. While flow is being diverted to removable cartridge 220b, removable cartridge 220a may be replaced, either automatically under the direction of remediation system 200 or manually, or inline regeneration thereof may take place, as discussed above. Although FIG. 2A has depicted removable cartridges 220a and 220b as being substantially the same size, it is to be appreciated that they may also be different in size. For example, removable cartridge 220a may be a larger, primary cartridge and removable cartridge 220b may be a smaller, secondary cartridge of sufficient size to support continuous flow during a brief replacement time or regeneration period for removable cartridge 220a.

[0093] After exiting remediation section 218, the substance proceeds to optional contaminant interrogation zone 214, wherein the contaminant profile of the substance may be evaluated a second time using spectrophotometer 216.

[0094] If the fluid has been satisfactorily remediated, as determined by the analyses taking place in contaminant interrogation zone 214, the fluid may proceed through continuous flow line 202 and exit via outlet end 206. If satisfactory remediation has not taken place (e.g., if carbon dioxide levels in the substance have not been reduced below a threshold concentration), system 200 may automatically divert the continuous flow through recirculation line 240 to a location upstream of remediation section 218, after which the substance may pass through one of removable cartridges 220a or 220b to promote further removal of carbon dioxide therefrom.

[0095] Although FIG. 2 A has shown a single remediation section 218 containing two removable cartridges 220a and 220b, it is to be appreciated that additional system configurations may include those having multiple remediation sections 218. The multiple remediation sections 218 may be arranged in parallel or in series. For example, FIG. 2B shows a diagram of remediation system 201 of the present disclosure in which two swing bed arrangements of removable cartridges are configured in parallel.

[0096] Other system configurations include those in which multiple removable cartridges are arranged upon a movable assembly. Movable assemblies include those that may move the removable cartridges rotationally, laterally, or in a continuous loop.

[0097] FIG. 3 A shows a diagram of a remediation system of the present disclosure in which multiple removable cartridges containing one or more amine-functionalized polymers, such as in the form of macroparticulates, are arranged upon a movable assembly. As shown, remediation system 300 includes continuous flow line 302 having inlet end 304 and outlet end 306. A substance in need of carbon dioxide removal enters continuous flow line 302 through inlet end 304 and proceeds to optional contaminant interrogation zone 310, in which the substance may be spectrophotometrically assayed using spectrophotometer 312. It is to be appreciated that non-spectrophotometric assays may also take place within optional contaminant interrogation zone 310, such as pH measurement or electrochemical assays, for example.

[0098] After being optionally assayed, the fluid then proceeds to remediation section 318, which may include one or more amine-functionalized polymers suitable for promoting uptake and release of carbon dioxide according to the disclosure herein. Monitoring of the amine-functionalized polymers may optionally take place with spectrophotometer 322. Two suitable configurations for movable assembly 320 are shown in FIGS. 4A and 4B, which are described in further detail below. Any cartridges upon movable assembly 320 that are not located within continuous flow line 302 may undergo regeneration with a separate continuous flow of reagent suitable for promoting decomplexation of carbon dioxide. Polymer layers containing the amine-functionalized polymers may be similarly configured.

[0099] When the amine-functionalized polymer has become laden with carbon dioxide, system 300 may operate movable assembly 320 (z.e., by rotation or lateral movement) to insert a fresh cartridge into continuous flow line 302. The spent cartridge may then be regenerated to recover the carbon dioxide therefrom. Movable assembly 320 may contain pairs of cartridges, so as not to disrupt the continuous flow through continuous flow line 302.

[0100] After exiting remediation section 318, the substance proceeds to optional contaminant interrogation zone 314, wherein the contaminant profile of the substance may be evaluated a second time using spectrophotometer 316. Analysis of the fluid may take placein a manner similar to that described above for optional contaminant interrogation zone 310. If the substance has been satisfactorily remediated, the substance may proceed through continuous flow line 302 and exit via outlet end 306. If satisfactory remediation has not taken place (e.g., if carbon dioxide concentrations in the substance have not been reduced below a threshold concentration), system 300 may automatically divert the continuous flow through recirculation line 340 to a location upstream of remediation section 318, after which the substance may again pass through remediation section 318 again to promote further removal of carbon dioxide therefrom.

[0100] Although FIG. 3 A has shown a single remediation section 318 containing removable cartridges, it is to be appreciated that additional system configurations may include those having multiple remediation sections 318. Each remediation section 318 may contain a movable assembly 320. The multiple remediation sections containing multiple removable cartridges may be arranged in parallel or in series. For example, FIG. 3B shows a diagram of remediation system 301 of the present disclosure in which two movable assemblies 320 containing removable cartridges are configured in parallel along branch line 330.

[0101] FIG. 4A shows a diagram of a movable assembly that is positionable by rotational motion. As shown, movable assembly 400 may include disk 401, which contains removable cartridges 402a-h. Removable cartridges 402a-h may include matched pairs (e.g., 402a, b; 402c, d; 402e,f and 402g, h), each matched pair containing similar types of macroparticulates, thereby allowing a replacement cartridge to be rotated into place once the functionalized macroparticulates in a first cartridge have become saturated with a contaminant. By having removable cartridges in matched pairs, continuous fluid flow may be maintained while remediating a particular contaminant of interest. Although FIG. 4A has depicted 8 removable cartridges 402a-h, it is to be appreciated that more or fewer removable cartridges may be present in other system configurations. It also is to be appreciated that removable cartridges 402a-h need not necessarily be arranged in matched pairs.

[0102] FIG. 4B shows a diagram of a movable assembly that is linearly positionable by lateral motion. As shown, movable assembly 450 may include strip 451, which contains removable cartridges 452a-f. Removable cartridges 452a-f may include matched pairs (e.g., 452a, b; 452c, d; and 452e,f), each matched pair containing similar types of macroparticulates, thereby allowing a replacement cartridge to be moved into place once the macroparticulatesin a first cartridge have become saturated with a contaminant. By having removable cartridges in matched pairs, continuous flow may be maintained while remediating a particular contaminant of interest. Although FIG. 4B has depicted 6 removable cartridges 452a-f, it is to be appreciated that more or fewer removable cartridges may be present in particular system configurations. It also is to be appreciated that removable cartridges 452a-f need not necessarily be arranged in matched pairs.

[0103] Alternative flow through configurations include those in which amine- functionalized polymers are disposed in parallel or series packed beds or polymer layers without being housed in a removable cartridge. In swing bed and similar configurations, carbon dioxide sequestration and de-complexation may take place without disrupting the continuous flow. Contaminant-laden macroparticulates in latent fluid communication with the continuous flow of the substance in need of carbon dioxide removal may be regenerated with a continuous flow of a reagent suitable for promoting release of carbon dioxide from the amine-functionalized polymer.

[0104] Embodiments disclosed herein include:

[0105] Embodiment 1. A composition comprising: an amine-functionalized polymer; and at least one additional moiety configured to promote binding of carbon dioxide by the amine-functionalized polymer or to promote release of carbon dioxide from the amine- functionalized polymer.

[0106] Embodiment 2. The composition of Embodiment 1, wherein the at least one additional moiety comprises a proton ionizable group.

[0107] Embodiment 3. The composition of Embodiment 2, wherein the proton ionizable group comprises a phenol.

[0108] Embodiment 4. The composition of any one of Embodiments 1-3, wherein the amine-functionalized polymer is a reaction product of an amine nucleophile and an epoxide- containing (meth)acrylic polymer or copolymer.

[0109] Embodiment 5. The composition of any one of Embodiments 1-4, wherein the at least one additional moiety is covalently bonded to the amine-functionalized polymer,present upon a small-molecule blended with the amine-functionalized polymer, or any combination thereof.

[0110] Embodiment 6. The composition of any one of Embodiments 1-5, wherein the amine-functionalized polymer comprises an epoxide-opening reaction product of an amine nucleophile, wherein the amine nucleophile is a polyamine, an alkanolamine, a ligand, or any combination thereof.[OHl] Embodiment 7. The composition of Embodiment 6, wherein the amine nucleophile is an alkanolamine selected from the group consisting of monoethanolamine, diethanolamine, and any combination thereof.

[0112] Embodiment 8. The composition of Embodiment 6, wherein the amine nucleophile is a polyamine.

[0113] Embodiment 9. The composition of Embodiment 8, wherein a first amine group of the polyamine promotes nucleophilic attack on an epoxide, and a second amine group of the polyamine is further functionalized with the at least one additional moiety.

[0114] Embodiment 10. The composition of any one of Embodiments 1-9, wherein multiple additional moieties are covalently bonded to the amine-functionalized polymer.

[0115] Embodiment 11. The composition of any one of Embodiments 1-9, wherein multiple amine-functionalized polymers are present in combination and each bear a different additional moiety.

[0116] Embodiment 12. The composition of any one of Embodiments 1-11, wherein a small-molecule is blended with the amine-functionalized polymer and provides the additional moiety.

[0117] Embodiment 13. The composition of any one of Embodiments 1-12, wherein the at least one additional moiety comprises a surfactant, a metal ion, or any combination thereof.

[0118] Embodiment 14. The composition of any one of Embodiments 1-13, wherein the composition is a polymer layer.

[0119] Embodiment 15. The composition of any one of Embodiments 1-13, wherein the composition is a plurality of macroparticulates.

[0120] Embodiment 16. The composition of any one of Embodiments 1-15, wherein each of the at least one additional moieties are covalently bonded to the amine-functionalized polymer; wherein the amine-functionalized polymer a) lowers a dielectric constant of an aqueous fluid and / or provides buffering to an aqueous fluid, b) contains a group providing pKa matching, c) contains a proton ionizable group whose acidity increases with temperature, d) provides surfactancy, e) provides a bound metal ion having catalytic properties, or any combination thereof.

[0121] Embodiment 17. A method comprising: exposing the composition of any one of Embodiments 1-16 to a fluid containing carbon dioxide; sequestering at least a portion of the carbon dioxide upon the amine-functionalized polymer as a carbamate, a carbonate, or any combination thereof to form a carbon dioxide-laden polymer; and separating the carbon dioxide-laden polymer from the fluid containing carbon dioxide.

[0122] Embodiment 18. The method of Embodiment 17, further comprising: removing at least a portion of the carbon dioxide form the carbon dioxide-laden polymer.

[0123] Embodiment 19. The method of Embodiment 18, wherein at least a portion of the at least one additional moieties undergoes deprotonation to promote removal of the carbon dioxide from the carbon dioxide-laden polymer.

[0124] Embodiment 20. The method of any one of Embodiments 17-19, wherein the fluid containing carbon dioxide comprises carbon dioxide gas, a gas mixture containing carbon dioxide, an aqueous carbon dioxide solution, or any combination thereof.

[0125] To facilitate a better understanding of the disclosure herein, the following examples of various representative embodiments are given. In no way should the following examples be read to limit, or to define, the scope of the invention.EXAMPLESMacroparticulate formation

[0126] Illustrative polymerization conditions. An isopropyl alcohol solution of 0.01033 M CuBr and 3.127 M glycidyl methacrylate was prepared. The total solution volume was 125 mL prior to polymerization. A catalytic amount of the n-butyl imine of 2- pydridinecarboxaldehyde (N-(pyridinyl-2-ylmethylene)butan-l -amine) was added as a ligand for Cu(I), followed by addition of a catalytic amount of azobisisobutyronitrile (AIBN) as a radical polymerization initiator (2: 1 molar ratio of ligand to Cu(I), 0.0066 equivalents of Cu(I) per mole of glycidyl methacrylate, and 0.005 g AIBN / g glycidyl methacrylate).

[0127] The entire reaction volume was stirred at 60-85°C and monitored for signs of polymerization. The polymerization reaction was allowed to continue until the reaction mixture could no longer be stirred effectively, as determined when the magnetic stir bar would no longer spin (approximately 40 minutes at 85°C). The increase in viscosity is indicative that polymerization to a first polymerization state occurred. Heating was discontinued when the reaction mixture could no longer be stirred effectively.

[0128] The polymer was precipitated by addition of 50-100 mL of methanol to the reaction mixture. The supernatant liquid was then decanted, and the polymer was redissolved in dichloromethane. The dichloromethane solution was then washed with an aqueous EDTA solution (0.2 M) to remove residual copper from the polymer. After EDTA extraction was performed, the polymer was again precipitated by addition of methanol (2-2.5 times the volume of the amount of di chloromethane present). Following precipitation, the polymer solids were squeezed to remove excess solvent.

[0129] Alternately, the polymerization reaction may be quenched by oxidation of Cu(I) to Cu(II), followed by dilution / precipitation with acetonitrile to isolate the polymer.

[0130] The polymer solids were then cut to size, optionally following extrusion, or rolled directly into substantially spherical balls. Curing at room temperature was then allowed to take place for 12 hours.

[0131] After preparation, the spheres were placed in a freezer to keep them from sticking together. When ready to conduct a functionalization reaction, a quantity of spheres was removed from the freezer, weighed, and functionalized as described below.

[0132] Illustrative Functionalization Conditions. A weighed quantity of trimethylamine (2.5 equivalents relative to the amount of glycidyl methacrylate calculatedbased upon the pre-weighed amount of polymer comprising the spheres) was combined with a quantity of ethanol (50 mL ethanol per 0.75 g of spheres) containing 0.50 equivalents of iminodiacetic acid (IDA) (relative to the amount of glycidyl methacrylate calculated based upon the pre-weighed amount of polymer comprising the spheres). Prior to addition of the spheres, the mixture was stirred under nitrogen until the IDA dissolved (15-20 minutes).

[0133] Once the IDA was fully dissolved, the pre-weighed quantity of poly(glycidyl methacrylate) spheres was removed from the freezer and combined with the reaction mixture. The reaction mixture was then heated for 5 hours at 74°C or at the reflux temperature of ethanol (78°C). As the reaction mixture was heated, the spheres expanded from their original size and a cavity formed inside the spheres. After 5 hours, the reaction medium was removed by decantation, and the functionalized macroparticulates were set aside to dry.CO2 Binding and Release

[0134] A three-neck round-bottom flask was charged with an amine or amine- functionalized polymer, along with other components, and the fluid was stirred at a rate slow enough to minimize surface turbulence. By minimizing disturbance of the surface, the exposed surface area at the fluid-gas interface above the surface may be determined. Flux was determined by dividing the carbon dioxide concentration within the fluid per unit (surface) area-time.

[0135] For carbon dioxide binding, the fluid was maintained at 25°C, and a 400 ppm CO2 in air standard gas mixture was exposed to the solution through a gas dispersion tube situated above the fluid. For carbon dioxide release, the fluid and absorbed carbon dioxide were heated at 100°C while flowing an argon or nitrogen stream as a carrier gas over the fluid at 300 seem. Heating was conducted by immersing the three-neck round bottom flask in an oil bath. A temperature of 80°C was reached within 20 minutes, and the final temperature was approximately 85-90°C depending on heating time. Any condensate from the fluid was trapped and returned using a water condenser.

[0136] The outlet concentration of carbon dioxide was monitored using a NDIR sensor commercially available from CO2Meter. The sensor was protected from moisture by using a drying column containing calcium chloride. The outlet concentration was used to determine the amount of carbon dioxide captured or released under various conditions.Small Molecule Amine Studies

[0137] Initial studies were conducted on aqueous solutions of small-molecule amines. Diethanolamine (pKa= 8.88) and diethylamine (pKa= 10.98) were dissolved in water at a concentration of 1 M, and the carbon dioxide fluxes at various pH values were determined. Measurements were conducted at 25°C. A I M aqueous KOH solution was also measured for comparison. Results are summarized in Table 1. In Table 1, [B] represents the concentration of unprotonated amine (or hydroxide) and [BH] represents the concentration of protonated amine conjugate acid (or H2O). J is the carbon dioxide flux (concentration / area»time).Table 1Flux is related to the transport efficiency and capture rate of the carbon dioxide. As shown, the alkanolamine reached achieved high carbon dioxide flux values at a pH value just above the pKavalue, and considerably lower carbon dioxide flux occurred below. At the same pH values where the alkanolamine achieved significant carbon dioxide flux values, the corresponding amine, in contrast, was much less effective due to extensive protonation of the amine nitrogen. At the pH values where the alkanolamine achieves effective carbon dioxide binding, the concentration of hydroxide remains small and is not believed to promote carbonate formation. This feature may account for the more ready release of carbon dioxide taking place from the alkanolamine.

[0138] In addition, the flux values for the alkanolamine were at least within an order of magnitude of KOH, but at a far lower pH value. The high flux values demonstrate that alkanolamines may facilitate a high capture rate for carbon dioxide that is at least somewhat comparable to KOH. It is to be understood that the flux values are not representative of the maximum amount of carbon dioxide that may be captured by each fluid, but rather how efficiently carbon dioxide may be captured under specified conditions.

[0139] Next, the alkanolamine solution was further modified with additional components to determine their effect on uptake of carbon dioxide. For these experiments, the pH was held constant at a value of approximately 9. Results are summarized in Table 2.Table 2Comparing Entries 2 and 3, it can be seen that including zinc acetate in combination with lecithin increased the carbon dioxide flux. When both zinc acetate and lecithin were present in a 1 M diethanolamine solution, an increase carbon dioxide flux was realized in Entry 4 in comparison to Entry 1.Alkanolamine Functionalized (Meth)acrylate Polymer Studies

[0140] Poly(glycidyl methacrylate) was functionalized with diethanolamine in the manner generally described above. The diethanolamine was added at a 1 : 1 stoichiometric ratio with respect to epoxide groups present in the polymer. Thereafter, the resulting amine- functionalized polymer was dissolved at various concentrations in water, and the outlet concentration of carbon dioxide was measured as a function of exposure time at 25°C. Carbon dioxide release rates were thereafter measured as a function of time at 80°C. The carbon dioxide uptake and release rates for a 0.0059 M KOH solution were also measured as a control.

[0141] FIGS. 5 and 6 are plots of outlet carbon dioxide pressure as a function of carbon dioxide exposure time for various concentrations of amine-functionalized polymer. As shown, the outlet pressure rapidly dropped upon exposing the amine-functionalized polymer solution to the carbon dioxide. Lower outlet pressures (more carbon dioxide absorption) were realized with increasing amine concentrations. Table 3 summarizes the amount of carbon dioxide captured by each amine solution and the capture efficiency. The amount of carbon dioxide represents the integrated concentration measured over time. Capture efficiency is the ratio of measured carbon dioxide at the outlet to carbon dioxide provided to the amine-functionalized polymer.Table 3The data shown in FIG. 6 is a separate replicate of that provided in FIG. 5. As shown in FIG. 6, the KOH solution more strongly adsorbed carbon dioxide than did either of the amine- functionalized polymer solutions.

[0142] FIGS. 7 and 8 are plots of outlet carbon dioxide pressure as a function of carbon dioxide exposure time for various concentrations of amine-functionalized polymer. As shown, rapid release of carbon dioxide was realized upon heating the amine- functionalized polymer. The data shown in FIG. 8 is a separate replicate of that provided in FIG. 7. As shown in FIG. 8, the KOH solution, in contrast, did not afford ready release of carbon dioxide under the same conditions at which release occurred from the amine- functionalized polymers. Thus, although the KOH solution provided somewhat better uptake of carbon dioxide relative to the amine-functionalized polymer, the overall performance was poorer due to the less-effective release rate.

[0143] FIG. 9 is a graph showing the amount of carbon dioxide taken up or released by the amine-functionalized polymer as a function of carbon dioxide exposure time or heating time. As shown, uptake of carbon dioxide was somewhat faster than release.

[0144] As shown in FIG. 10, heating may be used to promote release of the captured carbon dioxide. Heating in the presence of a phenol may also be utilized to further stimulate release of the captured carbon dioxide. FIG. 10 is a graph showing the amount of carbon dioxide released by the amine-functionalized polymer as a function of time in the presence of 4-methoxyphenol. As shown, carbon dioxide was released more rapidly in the presence of the phenol. Heating was performed at 80°C.Air Capture Test

[0145] To a cylindrical glass tube with a volume 4 cubic inches was added 40 grams of pellets prepared according to the macroparticle formulation above (Illustrative polymerization conditions) in

[0126] that had been functionalized with diethylenetriamine. Ambient air at a flow rate of 2 liters per minute (L / min) was measured for CO2 at the inlet and the outlet after passing over the pellets. FIG. 11 shows the change in concentration versus time. The data show removal of greater than 98% CO2 over most of the test duration. The cycles were when the instrument was switched to bypass mode showing the rate of capture.Uncatalyzed Thermal Release

[0146] Pellets from the air capture test above in the same glass tube were then subjected to heating (see FIG. 12). Using a heating wrap with a thermocouple to control temperature, heat was applied to the pellets at a flow rate of 2 L / min of argon as a carrier gas. Under these conditions, even with dilution by argon, the release of CO2 exceeded ambient air concentrations which indicate that the pellets concentrated and stored carbon dioxide until the appropriate amount of heat was applied.Fluorescent indicators

[0147] To demonstrate self-indicating pellets could be prepared to respond selectively to carbon dioxide, two dyes (A and B) were prepared using a Knoevenagel type condensation. These compounds could be attached covalently or noncovalently. It is presumed from experimental data that the compounds once impregnated into the pellet material did not readily leach off regardless of solvent or condition. These compounds would color shift to a longer visible wavelength once CO2 was absorbed. For example, in the pellet material, one dye turned orange, but when CO2 was absorbed, they turned yellow. This wasvisible to the unaided human eye, but also fluorescence was observed under black light at 365 nm.Macroparticles v. KOH

[0148] To demonstrate comparable efficacy against KOH, an industry standard carbon dioxide capture agent, several solution based formulations and polymer formulations were subjected to identical conditions. Formulations 2-4 show modifying surfactant, pH, buffer and catalyst improved performance with systematic control of variables. Formulations 5 and 6 show polymer prepared by the above methods and reacted with diethylamine, diethanolamine and diethylenetriamine. This is a solution based test from water.Thermal Release from 1-006

[0149] After achieving flux similar to KOH, 1-006 was subjected to heating and the CO2 concentration was monitored. Under these conditions, rapid thermal release at 80 °Cwas demonstrated and is illustrated in FIG. 13. This is in stark contrast to calcining methods that can approach 800 °C to achieve the same result.Catalytic Release

[0150] To demonstrate the rate of release can be accelerated with a thermally triggered catalyst when the pKa matches at temperature, the rate of release was plotted versus control (see FIG. 14).

[0151] Unless otherwise indicated, all numbers expressing quantities and the like in the present specification and associated claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the embodiments of the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claim, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0152] One or more illustrative embodiments incorporating various features are presented herein. Not all features of a physical implementation are described or shown in this application for the sake of clarity. It is understood that in the development of a physical embodiment incorporating the embodiments of the present invention, numerous implementation-specific decisions must be made to achieve the developer's goals, such as compliance with system-related, business-related, government-related and other constraints, which vary by implementation and from time to time. While a developer's efforts might be time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in the art and having benefit of this disclosure.

[0153] While various systems, tools and methods are described herein in terms of “comprising” various components or steps, the systems, tools and methods can also “consist essentially of’ or “consist of’ the various components and steps.

[0154] As used herein, the phrase “at least one of’ preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of’ allows a meaning thatincludes at least one of any one of the items, and / or at least one of any combination of the items, and / or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and / or at least one of each of A, B, and C.

[0155] Therefore, the disclosed systems, tools and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope of the present disclosure. The systems, tools and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and / or any optional element disclosed herein. While systems, tools and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the systems, tools and methods can also “consist essentially of’ or “consist of’ the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the elements that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.

Claims

WHAT IS CLAIMED IS:

1. A composition comprising: an amine-functionalized polymer; and at least one additional moiety configured to promote binding of carbon dioxide by the amine-functionalized polymer or to promote release of carbon dioxide from the amine-functionalized polymer.

2. The composition of claim 1, wherein the at least one additional moiety comprises a proton ionizable group.

3. The composition of claim 2, wherein the proton ionizable group comprises a phenol.

4. The composition of any one of claims 1-3, wherein the amine-functionalized polymer is a reaction product of an amine nucleophile and an epoxide-containing (meth)acrylic polymer or copolymer.

5. The composition of any one of claims 1-4, wherein the at least one additional moiety is covalently bonded to the amine-functionalized polymer, present upon a smallmolecule blended with the amine-functionalized polymer, or any combination thereof.

6. The composition of any one of claims 1-5, wherein the amine-functionalized polymer comprises an epoxide-opening reaction product of an amine nucleophile, wherein the amine nucleophile is a polyamine, an alkanolamine, a ligand, or any combination thereof.

7. The composition of claim 6, wherein the amine nucleophile is an alkanolamine selected from the group consisting of monoethanolamine, diethanolamine, and any combination thereof.

8. The composition of claim 6, wherein the amine nucleophile is a polyamine.

9. The composition of claim 8, wherein a first amine group of the polyamine promotes nucleophilic attack on an epoxide, and a second amine group of the polyamine is further functionalized with the at least one additional moiety.

10. The composition of any one of claims 1-9, wherein multiple additional moi eties are covalently bonded to the amine-functionalized polymer.

11. The composition of any one of claims 1-9, wherein multiple amine-functionalized polymers are present in combination and each bear a different additional moiety.

12. The composition of any one of claims 1-11, wherein a small-molecule is blended with the amine-functionalized polymer and provides the additional moiety.

13. The composition of any one of claims 1-12, wherein the at least one additional moiety comprises a surfactant, a metal ion, or any combination thereof.

14. The composition of any one of claims 1-13, wherein the composition is a polymer layer.

15. The composition of any one of claims 1-13, wherein the composition is a plurality of macroparticulates.

16. The composition of any one of claims 1-15, wherein each of the at least one additional moieties are covalently bonded to the amine-functionalized polymer; wherein the amine-functionalized polymer a) lowers a dielectric constant of an aqueous fluid and / or provides buffering to an aqueous fluid, b) contains a group providing pKamatching, c) contains a proton ionizable group whose acidity increases with temperature, d) provides surfactancy, e) provides a bound metal ion having catalytic properties, or any combination thereof.

17. A method comprising: exposing the composition of any one of claims 1-16 to a fluid containing carbon dioxide; sequestering at least a portion of the carbon dioxide upon the amine-functionalized polymer as a carbamate, a carbonate, or any combination thereof to form a carbon dioxide-laden polymer; and separating the carbon dioxide-laden polymer from the fluid containing carbon dioxide.

18. The method of claim 17, further comprising: removing at least a portion of the carbon dioxide form the carbon dioxide-laden polymer.

19. The method of claim 18, wherein at least a portion of the at least one additional moieties undergoes deprotonation to promote removal of the carbon dioxide from the carbon dioxide-laden polymer.

0. The method of any one of claims 17-19, wherein the fluid containing carbon dioxide comprises carbon dioxide gas, a gas mixture containing carbon dioxide, an aqueous carbon dioxide solution, or any combination thereof.

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