Carbon dioxide sorbent molecules, methods of making and uses

Abstract

Embodiments of the present disclosure generally relate to carbon dioxide sorbent molecules and methods for forming carbon dioxide sorbent molecules. Embodiments described herein also generally relate to methods for CO2 absorption and CO2 desorption. In one embodiment, a composition for absorbing or desorbing carbon dioxide is provided. The composition comprises carbon dioxide sorbent molecules. The carbon dioxide sorbent molecule comprises a melamine-formaldehyde adduct or reaction product modified with an organic amine source, the organic amine source being different from melamine.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit and priority of U.S. Provisional Application Serial No. 63 / 535,493, filed August 30, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0003] The embodiments disclosed herein generally relate to carbon dioxide sorbent molecules and methods for forming carbon dioxide sorbent molecules. The embodiments described herein also generally relate to methods for CO2 absorption and CO2 desorption. Background Technology

[0004] Carbon dioxide (CO2) is a major greenhouse gas that contributes significantly to global warming and climate change due to excessive emissions from the combustion of fossil fuels. Direct air capture (which involves the direct extraction of CO2 from the atmosphere) is one strategy for reducing CO2 emissions. In addition, two other options actively being explored for reducing CO2 emissions are carbon capture and storage (CCS) and carbon capture, storage and utilization (CCSU) technologies. A step in many CCS and CCSU technologies involves the reversible binding (absorption and desorption) of CO2 molecules.

[0005] Currently, there are very few technologies available for direct air capture of CO2 using CCSU and CCS. Most conventional direct air capture technologies involve metal hydroxides, such as sodium hydroxide and potassium hydroxide. Metal hydroxides can be cost-effective for CO2 absorption, but the energy cost of desorbing CO2 to generate value-added products is very high. This is because all the water needs to be evaporated before desorbing CO2 at very high temperatures of 800°C–1,200°C. Water evaporation can be avoided by reacting with calcium hydroxide to precipitate calcium carbonate, but this requires a desorption temperature of approximately 840°C.

[0006] Therefore, there is a need for new and improved adsorbents and compositions for capturing and releasing CO2. There is also a need for new and improved methods for capturing and releasing CO2. Summary of the Invention

[0007] Overview

[0008] The embodiments described herein generally relate to carbon dioxide adsorbent molecules and methods for forming carbon dioxide adsorbent molecules. The embodiments described herein also generally relate to methods for CO2 absorption and CO2 desorption. For CO2 absorption and CO2 desorption, the carbon dioxide adsorbent molecules can exist in solution or in a solid state. The embodiments described herein can be superior to conventional CO2 capture technologies. Furthermore, the carbon dioxide adsorbent molecules can be regenerated and recycled after CO2 desorption for further use.

[0009] In one embodiment, a composition for absorbing or desorbing CO2 is provided. The composition comprises a carbon dioxide adsorbent molecule containing a melamine-formaldehyde reaction product modified with an organic amine source, which is different from melamine.

[0010] In another embodiment, a composition for absorbing or desorbing CO2 is provided. The composition comprises a carbon dioxide adsorbent molecule containing a reaction product of glyoxal and an organic amine source containing a urea functional group.

[0011] In another embodiment, a method is provided comprising: contacting a gas stream containing CO2 with a composition containing water, an additive, and carbon dioxide adsorbent molecules as described herein; and precipitating an adsorbent-CO2 complex containing CO2 bound to the carbon dioxide adsorbent molecules. Attached Figure Description

[0012] To gain a more detailed understanding of the features described above in this disclosure, a more specific description of the disclosure, which has been briefly outlined above, can be obtained by referring to embodiments (some of which are shown in the accompanying drawings). However, it should be noted that the drawings illustrate only exemplary embodiments and should not be considered as limiting their scope, allowing for other equally effective embodiments.

[0013] Figure 1 The distortion-free polarization transfer gain method (DEPT) carbon-13 nuclear magnetic resonance of an exemplary carbon dioxide adsorbent molecule is shown. 13 CNMR spectrum.

[0014] Figure 2 It is a superimposed image showing the Fourier transform mid-infrared (FT-MIR) spectrum of CO2 absorbed by an exemplary carbon dioxide adsorbent molecule.

[0015] Figure 3 The carbon-13 nuclear magnetic resonance (NMR) of various materials prepared and used during the synthesis of exemplary carbon dioxide adsorbent molecules using aminoguanidine is shown. 13 C NMR spectrum.

[0016] Figure 4 This is a superimposed graph of thermogravimetric analysis (TGA) data of CO2 bound to an exemplary carbon dioxide adsorbent molecule.

[0017] Figure 5A Data from the outgassing analysis of the glyoxal-bis-iminoguanidine-CO2 comparative example are shown.

[0018] Figure 5B Data from the analysis of the escaping gas of CO2 bound to an exemplary carbon dioxide adsorbent molecule are shown.

[0019] Figure 6 Data on the mass increase of an exemplary carbon dioxide adsorbent as a function of CO2 absorption time are shown.

[0020] Figure 7 Various materials prepared and used during the synthesis of exemplary carbon dioxide adsorbents using guanidine are shown. 13 CNMR spectrum.

[0021] Figure 8 It is a superimposed image showing the FT-MIR spectra of CO2 desorption through an exemplary carbon dioxide adsorbent molecule.

[0022] Figure 9 The FT-MIR spectra of carbon dioxide (top subplot) desorbed from an exemplary carbon dioxide adsorbent molecule and CO2 alone (bottom subplot) are shown.

[0023] Figure 10 A graph of CO2 absorption versus time is shown for a first absorption-desorption cycle of a mixture comprising a carbon dioxide adsorbent and a caustic solution for at least one embodiment of this application.

[0024] The accompanying drawings included herein illustrate various embodiments of this disclosure. It is conceivable that elements and features of one embodiment may be advantageously incorporated into other embodiments without further elaboration. Detailed Implementation

[0025] Detailed instructions

[0026] The embodiments described herein generally relate to carbon dioxide adsorbent molecules and methods for forming carbon dioxide adsorbent molecules. The embodiments described herein also generally relate to methods for CO2 absorption and CO2 desorption. The compositions described herein can overcome the challenges faced by conventional CO2 capture and release technologies, such as direct air capture (DAC) technologies. For example, the compositions described herein can have significantly higher absorption and / or desorption efficiencies compared to conventional DAC technologies and other conventional technologies for CO2 capture and release.

[0027] In summary, and in some embodiments, this disclosure provides compositions comprising carbon dioxide adsorbent molecules and optionally a solvent such as water. During use, the carbon dioxide adsorbent molecules can be used in methods for removing CO2 from a gaseous source. For example, the method may include introducing a gaseous source together with a composition comprising carbon dioxide adsorbent molecules (e.g., aminoguanidine-modified melamine-formaldehyde adduct or guanidine-modified melamine-formaldehyde adduct). The composition may further comprise a solvent such that the composition is in the form of a solution or suspension. Additionally or alternatively, the composition may be in the form of a solid composition. Additionally or alternatively, the composition may be in the form of a saturated substrate or coated substrate comprising carbon dioxide adsorbent molecules. Contact between CO2 and the carbon dioxide adsorbent molecules can result in complexation to form carbonates and / or bicarbonates of the carbon dioxide adsorbent molecules. Complexation can lead to precipitation, and the precipitated salt can be removed from, for example, the solution or suspension. In some embodiments, the precipitated salt can be subjected to heat or other techniques for separating (or releasing) CO2 gas from the precipitated salt, while simultaneously regenerating the carbon dioxide adsorbent molecules. The released CO2 gas can be stored or used in various applications.

[0028] The headings are used for convenience only and do not limit the scope of this disclosure. The embodiments described herein can be combined with other embodiments.

[0029] As used herein, a “composition” may comprise one or more components of the composition, one or more reaction products of two or more components of the composition, and / or a balance of remaining starting components (one or more). The compositions disclosed herein can be prepared by any suitable mixing process.

[0030] As used herein, "carbon dioxide enrichment composition" and "CO2 enrichment composition" refer to compositions in which the relative amount (or concentration) of CO2 after exposure to or contact with CO2 is greater than the relative amount of CO2 in the composition before such exposure or contact. For example, if a composition contains 1% CO2 before exposure to or contact with CO2, then after exposure to or contact with CO2, the composition will contain more than 1% CO2. The CO2 sequestered or captured by one or more components of the composition may be carbonate (CO3-). 2- Salt, bicarbonate (HCO3) - The salt, the reaction product of one or more components of the composition (e.g., urethane), or CO2 physically bound by electrostatic interactions (e.g., van der Waals forces).

[0031] As used herein, “carbon dioxide-depleted composition” and “CO2-depleted composition” refer to compositions in which the relative amount (or concentration) of CO2 after desorption or release of CO2 is less than the relative amount of CO2 in the composition before desorption or release. For example, if the composition contains 1% CO2 before desorption or release of CO2, then the composition will contain less than 1% CO2 before desorption or release.

[0032] In some embodiments, a carbon dioxide adsorbent molecule capable of removing CO2 gas is provided. In some embodiments, the carbon dioxide adsorbent molecule is a formaldehyde-derived molecule. The carbon dioxide adsorbent molecule can be dissolved or suspended in an aqueous solution, or can be used in a solid state.

[0033] In some embodiments, carbon dioxide adsorbent molecules are formed by reacting melamine with formaldehyde and then sulfonating the melamine-formaldehyde reaction product. Sulfonation improves the water solubility of the carbon dioxide adsorbent molecules. In some embodiments, the sulfonated product is then reacted with aminoguanidine. The aminoguanidine group (or other organic amine group) can be used as a functional ligand to scavenge or bind CO2. The CO2 scavenged or bound by the aminoguanidine (or other organic amine group) can be in the form of, for example, carbonates and / or bicarbonates. Guanidine or polyamines can be used instead of aminoguanidine.

[0034] Exposure of the carbon dioxide adsorbent molecule to CO2 gas causes the molecule to precipitate from the solution. The precipitate can be filtered off if necessary. In at least one embodiment, the molecule can be heated to desorb CO2. The embodiments described herein enable CO2 concentration.

[0035] Unlike conventional CO2 absorption technologies, the carbon dioxide adsorbent molecules (and compositions thereof) described herein can achieve rapid CO2 absorption within approximately 30 seconds. The carbon dioxide adsorbent molecules and compositions thereof disclosed herein may have an absorption capacity of approximately 0.001-5.000 moles of CO2 per mole of carbon dioxide adsorbent molecule, although other ranges are also considered.

[0036] Furthermore, the embodiments described herein can achieve desorption at low temperatures (e.g., below about 160°C). In some non-limiting examples, desorption can be performed at a temperature of about 105°C. In other non-limiting examples, the desorption temperature can be from about 120°C to about 130°C.

[0037] Unlike conventional techniques, the carbon dioxide adsorbent molecules described herein can be synthesized using a one-pot method. Furthermore, this synthesis can be solvent-free. Additionally, compared to existing methods, these carbon dioxide adsorbent molecules exhibit improved solubility, allowing for higher concentrations of dissolved active adsorbent. In contrast, conventional adsorbent synthesis consistently uses organic solvents, involves multiple filtrations, and is limited to active concentrations of 1 mM or less.

[0038] Composition

[0039] Embodiments of this disclosure generally relate to compositions for absorbing and / or desorbing CO2. These compositions typically comprise a carbon dioxide adsorbent molecule and one or more optional components. The one or more optional components may comprise a solvent, an additive, or a combination thereof.

[0040] When a solvent is included, the composition can be in the form of a solution or suspension containing the carbon dioxide adsorbent molecule and the solvent. Alternatively or additionally, the carbon dioxide adsorbent molecule can be used in a solid state.

[0041] IA carbon dioxide adsorbent molecules

[0042] In some embodiments, the composition for absorbing, desorbing, or both of CO2 comprises a carbon dioxide adsorbent molecule comprising a reaction product or adduct of (a) melamine, (b) formaldehyde, and (c) an organic amine, wherein the organic amine is different from melamine. In at least one embodiment, the composition comprises a carbon dioxide adsorbent molecule comprising a reaction product or adduct of (a) an organic amine with (b) a reaction product or adduct of melamine and formaldehyde, wherein the organic amine is different from melamine.

[0043] Such a carbon dioxide adsorbent molecule can be represented by formula (IA):

[0044] .

[0045] In formula (IA), A 1 A 2 and A 3 Each of these can be independently a methylene (-CH2-), a dimethylene ether (-CH2-O-CH2-), or other groups.

[0046] In equation (IA), R 1 R 2 and R 3Each of these components can independently be a structural moiety containing functional groups for binding CO2. Such a structural moiety can be referred to as a functional ligand. The binding between the functional group of this structural moiety and CO2 can be physical binding, chemical binding, or a combination thereof. In some embodiments, R... 1 R 2 and R 3 At least one of them can be a functional group capable of solubilizing the carbon dioxide adsorbent molecule, such as a polar, non-ionizable, ionizable, or salt thereof. The inclusion of an ionizable or polar, non-ionizable functional group can help improve the solubility of the carbon dioxide adsorbent molecule, depending on, for example, the type of solvent used, the polarity of the solvent, and / or whether it is an aqueous or organic solvent. In some embodiments, R 1 R 2 and R 3 At least one of them can be a functional group that enables coupling or attachment to a solid support. In the case of including a functional group that enables coupling or attachment (e.g., by chemical bond) to a solid support, the carbon dioxide adsorbent molecule can be readily removed from a liquid-containing system for CO2 absorption or CO2 desorption.

[0047] In at least one embodiment, the carbon dioxide adsorbent molecule can be represented by formula (IB):

[0048] .

[0049] In formula (IB), A 1 A 2 and A 3 Each of these groups can independently be methylene (-CH2-), dimethylene ether (-CH2-O-CH2-), or other groups. In formula (IB), R 1 R 2 and R 3 Each of them can be used with R in equation (IA). 1 R 2 and R 3 Same. In formula (IB), m can be an integer from 1 to 1,000, for example 1 to 100, for example 1 to 10. Formula (IB) contains a melamine-formaldehyde polymer or resin core, R 1 R 2 and R 3 It is chemically coupled with it.

[0050] Unless otherwise specified or the context clearly indicates otherwise, the implementation of formula (IA) described herein is applicable to the implementation of formula (IB).

[0051] As further described below, the core of formula (IA) can be formed by the reaction of melamine with formaldehyde or its derivatives. The core of formula (IA) is represented by formula (II-A):

[0052]

[0053] In formula (II-A), the wavy bond represents a bond with an R group (e.g., R...). 1 R 2 and R 3 The connection of ) . A in formula (II-A) 1 A 2 and A 3 As stated above.

[0054] Returning to equation (IA), and in some implementations, R of equation (IA) 1 R 2 and R 3 Each of the R groups can independently be hydrogen, an unsubstituted hydrocarbon group, a substituted hydrocarbon group, or a functional group containing at least one element from Groups 13-17 of the periodic table. When the R group is a functional group containing at least one element from Groups 13-17, the R group can be a halogen (F, Cl, Br, or I), O, N, Se, Te, P, As, Sb, S, B, Si, Ge, Sn, Pb, etc., for example, C(O)R. C(S)NR 2. C(O)OR NR 2. OR 、SeR TeR PR 2. AsR 2. SbR 2. SR SO x (where x = 2 or 3), BR 2. SiR 3. GeR 3. SnR 3. PbR 3rd grade, of which R It is independently hydrogen or an unsubstituted hydrocarbon group, or at least one heteroatom of which has been inserted into the unsubstituted hydrocarbon group.

[0055] R of formula (IA) 1 R 2 and R 3Each of the elements can independently have any suitable number of carbon atoms, such as 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 5 carbon atoms, or 1 to 4 carbon atoms. In some embodiments, R of formula (IA) 1 R 2 and R 3 The number of carbon atoms in each of these equations can be independently 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20. Each of these numbers may be preceded by the phrases “about,” “at least about,” “less than about,” or “greater than about,” and any of these numbers may be used alone to describe an open range or in combination to describe a closed range. R in equation (IA) 1 R 2 and R 3 Each of these can be independently linear or branched, saturated or unsaturated, cyclic or acyclic, aromatic or non-aromatic. Regarding saturation, R in equation (IA) 1 R 2 and R 3 Each of them can be independently fully saturated, partially unsaturated, or completely unsaturated.

[0056] In some instances, R of equation (IA) 1 R 2 or R 3 One or more of these can be unsubstituted hydrocarbon groups. An "unsubstituted hydrocarbon group" refers to a group consisting only of hydrogen and carbon atoms. Illustrative but non-limiting examples of unsubstituted hydrocarbon groups include alkyl groups having 1-20 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl and tert-butyl, pentyl, hexyl, heptyl, octyl, ethyl-2-hexyl, isooctyl, nonyl, n-decyl, isodecyl or isomers thereof; alicyclic groups having 3-20 carbon atoms, such as cyclopentyl or cyclohexyl; aromatic groups having 6-20 carbon atoms, such as phenyl or naphthyl; or any combination thereof.

[0057] In some implementations, R of formula (IA) 1 R 2 or R 3 One or more of these can be substituted hydrocarbon groups. A "substituted hydrocarbon group" refers to an unsubstituted hydrocarbon group in which at least one hydrogen atom is replaced by at least one heteroatom or heteroatom-containing group, such as one or more elements from groups 13-17 of the periodic table, for example, halogens (F, Cl, Br, or I), O, N, Se, Te, P, As, Sb, S, B, Si, Ge, Sn, Pb, etc., such as C(O)R. C(S)NR 2. C(O)OR NR 2. OR 、SeR TeR PR 2. AsR 2. SbR 2. SR SO x (where x = 2 or 3), BR 2. SiR 3. GeR 3. SnR 3. PbR 3rd grade, of which R It is independently hydrogen or an unsubstituted hydrocarbon group, or at least one heteroatom of which has been inserted into the unsubstituted hydrocarbon group.

[0058] As used herein, references to R groups, alkyl groups, substituted alkyl groups, hydrocarbon groups, or substituted hydrocarbon groups (e.g., butyl) without specifying a particular isomer clearly disclose all isomers (e.g., n-butyl, isobutyl, sec-butyl, and tert-butyl). For example, a reference to an R group having four carbon atoms clearly discloses all its isomers. When a compound is described herein without specifying a particular isomer, enantiomer, or diastereomer, for example, in the form of a chemical formula or chemical name, the description is intended to include every isomer and enantiomer of the described compound (alone or in any combination).

[0059] IA1. R group as an organic amine group

[0060] In some implementations, R of formula (IA) 1 R 2 or R 3One or more of these can be organic amine groups. The organic amine group may be derived from an organic amine source used during the formation of the carbon dioxide adsorbent molecule. The organic amine group (and / or organic amine source) may include or be derived from any suitable amine, such as primary amines, secondary amines, tertiary amines, polyamines, imines, aminocarboxamidine, polyimines, Schiff bases, amines capable of forming imines, amines capable of forming Schiff bases, or combinations thereof. Aminocarboxamidine includes guanidine. The organic amine group (and / or organic amine source) may include or be derived from any suitable amino acid (e.g., alanine, arginine, asparagine, aspartic acid, cysteine, glutamine, glutamic acid, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine), or any suitable polypeptide formed from two or more amino acids.

[0061] In at least one embodiment, R of formula (IA) 1 R 2 and R 3 Each of these can independently be an organic amine group represented by formula (III-A), (III-B), (III-C), (III-D), or (III-E):

[0062]

[0063] or .

[0064] In formula (III-A)-(III-E), the wavy bond represents the connection between the R group in formula (IA) and the NH group of the amine in formula (IA), or the connection between the R group in formula (IA) and the carbon of the dimethylene ether (-CH2-O-CH2-) in formula (IA). That is, the wavy bond represents the connection between the R group in formula (IA) and the NH group of the amine in formula (IA) and the carbon of the dimethylene ether (-CH2-O-CH2-). 1 A 2 and / or A 3 The connection.

[0065] As described above, the carbon dioxide adsorbent molecule may contain both a methylene group and a dimethylene ether that connects an R group and an amine NH group.

[0066] Formula (III-A) is an aminoguanidine group, Formula (III-B) is a guanidine group, Formula (III-C) is an amidoyl urea group, Formula (III-D) is a diethylenetriamine group, and Formula (III-E) is a polyethyleneimine (PEI) group.

[0067] The organic amine groups of formulas (III-D) and (III-E) can be used to serve as both a CO2 capture structural part and a tail structure to promote solubility.

[0068] In equation (III-E), n can be an integer from about 1 to about 500, for example from about 1 to about 250, for example from about 1 to about 25.

[0069] The organic amine group may come from an organic amine source used during the formation of the carbon dioxide adsorbent molecule.

[0070] In some implementations, R of formula (IA) 1 R 2 and R 3 Each of these can be a salt of an organic amine group. The organic amine salt group may contain a positively charged nitrogen atom and a counter anion. The counter anion of the organic amine salt group may contain at least one element from Groups 13-17 of the periodic table, such as halogens (F, Cl, Br, or I), O, N, P, S, B, etc. In some instances, the salt is a chloride salt, bromide salt, phosphate salt, sulfate salt, aminosulfonic acid (SO3NH2) salt, bicarbonate salt, or carbonate salt. In some instances, the counter anion may be selected from the group consisting of: F... – Cl – ,Br – and I – BF4 – CF3CO2 – BCl4 – BBr4 – BI4 – NO3 – NO2 – ClO4 – IO3 – ClO3 – BrO3 – ClO2 – ,OCl – ,OBr – CN – OCN – SCN – KMnO4 – HSO4 – HSO3 – SO3 2– H2PO4 – OH – CH3CO2 – HCO2 – HCO3 – CO3 2–H3CC6H4SO2 – F3CSO3 – CH3SO3 – C7H5O2 – C3H5O3 – (CH3(CH2)3)2HPO4 – and (C6H5)4B – wait.

[0071] For equation (IA) R 1 R 2 or R 3 Illustrative but non-limiting examples of useful organic amine salt groups may include aminoguanidine salts (e.g., HCl salts, phosphates, sulfates, bicarbonates, etc.) or guanidine salts (e.g., HCl salts, phosphates, sulfates, aminosulfonates, carbonates, etc.).

[0072] IA2. R group as an ionizable functional group (or its salt)

[0073] As described above, and in some embodiments, R of formula (IA) 1 R 2 and R 3 At least one of them can be an ionizable functional group or a salt thereof. The ionizable functional group (or its salt) can help dissolve the carbon dioxide adsorbent molecule.

[0074] The ionizable functional group can exist as an ion, a salt, or a combination thereof. The ionizable functional group (or its salt) differs from the organic amine and melamine. The ionizable functional group or its salt can be derived from the ionizable functional group source or salt source used during the formation of the carbon dioxide adsorbent molecule.

[0075] For equation (IA) R 1 R 2 or R 3 Illustrative but non-limiting examples of useful ionizable functional groups (or their salts) may be represented by formula (IV-A), formula (IV-B), or combinations thereof:

[0076] or .

[0077] As shown, Z in formulas (IV-A) and (IV-B) is the R group of formula (IA). In formulas (IV-A) and (IV-B), the wavy bond represents the connection between the R group of formula (IA) (which is "Z" in IV-A / IV-B) and the NH group of the amine in formula (IA), or the connection between the R group of formula (IA) and the carbon of the dimethylene ether (-CH2-O-CH2-) in formula (IA). That is, the wavy bond represents the connection between the R group of formula (IA) and the NH group of the amine in formula (IA) and the carbon of the dimethylene ether (-CH2-O-CH2-). 1 A 2 and / or A 3 The connection.

[0078] In formulas (IV-A) and (IV-B), Z is a functional group containing at least one element from groups 13-17 of the periodic table (e.g., N, P, O, S, or combinations thereof). In some instances, Z contains sulfate, sulfonate, carboxylic acid, phosphate, phosphonate, or combinations thereof. In some instances, Z contains -SO3H, -OSO3H, -CO2H, -OPO3R. 2. -PO3R 2. Hydrocarbon groups substituted with -SO3H, -OSO3H, -CO2H, and -OPO3R 2-substituted hydrocarbon groups, with -PO3R 2-substituted hydrocarbon groups, or combinations thereof, wherein each R Independently, it is hydrogen or a hydrocarbon group (e.g., alkyl). In some embodiments, the group represented by formula (IV-A) or (IV-B) may be in anionic form (e.g., -SO3). - ).

[0079] Formula (IV-B) represents the salt. The anion of formula (IV-B) is represented by Z. - The cation (X) in formula (IV-B) can be monatomic or polyatomic. Monatomic cations may include alkali metals (e.g., Li, Na, K, Rb, and Cs), alkaline earth metals (e.g., Be, Mg, Ca, Sr, and Ba), transition metals (e.g., Fe, Zn, Mn), or combinations thereof. Polyatomic cations may include, for example, ammonium (NR... 4 + , where each R Independently hydrogen, hydrocarbon group (e.g., alkyl), pyridine (or a combination thereof).

[0080] The ionizable functional group may be derived from an ionizable functional group source used during the formation of the carbon dioxide adsorbent molecule. The salt of the ionizable functional group source may be derived from a salt source used during the formation of the carbon dioxide adsorbent molecule. Alternatively or additionally, the ionizable functional group may be prepared and then the ionizable functional group may be made into a salt.

[0081] In some implementations, the carbon dioxide adsorbent molecule does not contain ionizable functional groups or salt groups.

[0082] IA3. R group as a polar, non-ionizable functional group

[0083] As described above, and in some embodiments, R of formula (IA) 1 R 2 and R 3 At least one of them can be a polar, non-ionizable functional group. This polar, non-ionizable functional group (or its salt) can help dissolve the carbon dioxide adsorbent molecule.

[0084] The polar, non-ionizable functional group is different from the ionizable functional group (or its salt), the organic amine, and the melamine. The polar, non-ionizable functional group can be derived from a source of polar, non-ionizable functional groups used during the formation of the carbon dioxide adsorbent molecule.

[0085] For equation (IA) R 1 R 2 or R 3 An illustrative but non-limiting example of a useful polar, non-ionizable functional group can be represented by equation (IV-C):

[0086] .

[0087] As shown, Z′ in formula (IV-C) is the R group of formula (IA).

[0088] In formula (IV-C), the wavy bond represents the connection between the R group in formula (IA) and the NH group of the amine in formula (IA), or the connection between the R group in formula (IA) and the carbon of the dimethylene ether (-CH2-O-CH2-) in formula (IA). That is, the wavy bond represents the connection between the R group in formula (IA) and the NH group of the amine in formula (IA) and the carbon of the dimethylene ether (-CH2-O-CH2-). 1 A 2 and / or A 3 The connection.

[0089] In formula (IV-C), Z′ is a functional group containing at least one element from Groups 13-17 of the periodic table (e.g., a halogen (e.g., F, Cl, Br, or I), N, P, O, S, or combinations thereof). In some instances, Z′ contains a hydroxyl group (-OH), a ketone, an ester, an amide, a carbamate, a urethane, a halogen, or a combination thereof. Additionally or alternatively, Z′ may contain a substituted hydrocarbon group, such as those described above.

[0090] The polar, non-ionizable functional group may originate from a source of polar, non-ionizable functional groups used during the formation of the carbon dioxide adsorbent molecule. In some embodiments, the carbon dioxide adsorbent molecule does not contain a polar, non-ionizable functional group.

[0091] IA4. R group, used to bind to solid supports, or as carbon dioxide adsorbent molecules embedded or dispersed within a matrix.

[0092] In some implementations, R of formula (IA) 1 R 2 or R 3 At least one of them can be a functional group capable of coupling, binding, or otherwise attaching carbon dioxide adsorbent molecules to a solid support. In such embodiments, the functional group can be a reactive functional group, such as an olefin, methacrylate, hydroxymethyl alcohol, silane, aminosilane, aldehyde, or ketone. These reactive functional groups can react with reactive functional groups on the solid support. In some embodiments, R of formula (IA) 1 R 2 and R 3 At least one of them may represent a solid support, a solid phase, a support matrix, or a combination thereof.

[0093] The solid support, solid phase, support matrix, or combination thereof may include particles, beads, fibers, films, polymers, powders, foams, or combinations thereof. In some embodiments, the carbon dioxide adsorbent molecules may be chemically coupled (chemically bonded) to the solid support, solid phase, or support matrix.

[0094] Additionally or alternatively, the carbon dioxide adsorbent molecules may be physically coupled to a solid support, solid phase, or support matrix. Alternatively or alternatively, the carbon dioxide adsorbent molecules may be embedded in and / or dispersed within a solid support, solid phase, or support matrix.

[0095] The beads may be composed of materials such as sand, ceramics, glass, polymers, cellulose, inorganic, organic, and / or bio-based substrates. The beads may be hollow or filled. The beads may be coated. The beads may be of any suitable size. In some embodiments, the beads are coated with carbon dioxide adsorbent molecules. In at least one embodiment, the beads contain reactive functional groups chemically coupled to form the carbon dioxide adsorbent molecules.

[0096] The fiber may be composed of materials such as ceramics, glass, polymers, cellulose, inorganic, organic, and / or bio-based substrates. The fiber may be coated. The fiber may have any suitable size or length. In some embodiments, the fiber is coated with carbon dioxide adsorbent molecules. In at least one embodiment, the fiber contains reactive functional groups to chemically couple and form the carbon dioxide adsorbent molecules.

[0097] The film containing the carbon dioxide adsorbent molecules can be placed on a flexible or rigid surface. The film containing the carbon dioxide adsorbent molecules can be placed on a silicon wafer. The film can have any suitable size or length.

[0098] In some embodiments, the membrane can be prepared by using a concentrated solution of carbon dioxide adsorbent molecules or by diluting the carbon dioxide adsorbent molecules in water to form a solution, and then spraying the solution onto a substrate. For example, a solution containing carbon dioxide adsorbent molecules can be spin-coated and coupled onto a silicon wafer, and then dried. The membrane can then be used to absorb CO2. After CO2 absorption, the membrane can be exposed to a voltage, for example, to promote CO2 desorption.

[0099] Additionally or alternatively, the solid composition may comprise a powder containing the carbon dioxide adsorbent molecules. Here, the carbon dioxide adsorbent molecules may be cured under any suitable conditions, such as environmental, thermal, chemical, coalescence, or catalytic conditions, and then ground into a powder. In some embodiments, the carbon dioxide adsorbent molecules may be coupled to a polymer and cured using a catalyst via heating. In some embodiments, the powder may be arranged as an adsorbent medium bed, for example, in the form of a tube, membrane, or other bed.

[0100] Additionally or alternatively, the solid composition may comprise a foam, and the foam may contain the carbon dioxide adsorbent molecules. The foam may comprise a dispersion of liquid and air and / or bubbles. The carbon dioxide adsorbent molecules may be in the liquid phase of the foam, may be present within the bubbles of the foam, or a combination thereof. In some embodiments, the foam may be prepared by first dispersing the carbon dioxide adsorbent molecules in a liquid medium. The reinforced liquid may be formulated into a foam containing closed-cell and / or open-cell bubbles, wherein the size of the foam pores is any suitable size, such as nanometers, micrometers, millimeters, centimeters, or combinations thereof. The foam may be cured under any suitable conditions such as environmental conditions, thermal conditions, chemical conditions, or catalytic conditions. Here, the carbon dioxide adsorbent molecules are dispersed within a matrix.

[0101] IA5. Exemplary carbon dioxide adsorbent molecules

[0102] Illustrative but non-limiting examples of the carbon dioxide adsorbent molecule may include one or more of the following:

[0103]

[0104]

[0105] For carbon dioxide adsorbent molecules represented by formulas (VA) to (VE), each X + It can be independently a monatomic or polyatomic cation, such as those mentioned above, such as Na, K, and pyridine. Ammonium or alkylammonium. In formulas (VE), (VJ), (VO), (VP), and (VQ), each of x, y, and z is independently an integer from about 1 to about 500, for example from about 1 to about 250, for example from about 1 to about 25.

[0106] The carbon dioxide adsorbent molecules represented by formulas (VA) to (VE) are bifunctionalized carbon dioxide adsorbent molecules linked by melamine-formaldehyde. Formulas (VA) to (VE) are, respectively, the reaction products (or adducts) of melamine-formaldehyde reaction products with aminoguanidine (as shown by bis-aminoguanidine in formula (VA)), guanidine (as shown by bis-guanidine in formula (VB)), amidourea (as shown by bis-amidinylurea in formula (VC)), diethylenetriamine (as shown by bis-diethylenetriamine in formula (VD)) or polyethyleneimine (as shown by bis-PEI in formula (VE)).

[0107] The carbon dioxide adsorbent molecules represented by formulas (VK) to (VO) are trifunctionalized carbon dioxide adsorbent molecules linked by melamine-formaldehyde. Formulas (VK) to (VO) are, respectively, the reaction products (or adducts) of melamine-formaldehyde reaction products with aminoguanidine (as shown by tri-aminoguanidine in formula (VK)), guanidine (as shown by tri-guanidine in formula (VL)), amidourea (as shown by tri-amidourea in formula (VM)), diethylenetriamine (as shown by tri-diethylenetriamine in formula (VN)) or polyethyleneimine (as shown by tri-PEI in formula (VO)).

[0108] The carbon dioxide adsorbent molecules represented by formulas (VP) and (VQ) are trifunctionalized carbon dioxide adsorbent molecules linked by melamine and formaldehyde. Formula (VP) is the reaction product (or adduct) of melamine-formaldehyde with aminoguanidine and PEI. Formula (VQ) is the reaction product (or adduct) of melamine-formaldehyde with guanidine and PEI.

[0109] In some implementations, carbon dioxide adsorbent molecules represented by formula (IA) can be used for the sequestration of CO2.

[0110] Various other carbon dioxide adsorbent molecules may also be considered. Some of these carbon dioxide adsorbent molecules are described elsewhere in this document, for example, in the “variants” of the synthesis described below.

[0111] IB Optional components of the composition

[0112] As described above, the compositions disclosed herein (e.g., compositions for absorbing CO2, desorbing CO2, or both) may comprise one or more optional components. These optional components may comprise solvents, additives, or combinations thereof.

[0113] Solvents useful for the compositions described herein may include aqueous solvents, organic solvents, or combinations thereof. Aqueous solvents may be selected from the group consisting of: water, distilled water, deionized water, ultrapure water, and combinations thereof. Organic solvents may be selected from the group consisting of: halogenated solvents, alcohol solvents, alkyl carbonate solvents, ketone solvents, hydrocarbon solvents, ester solvents, ether solvents, and combinations thereof. Halogenated solvents may be selected from the group consisting of: dichloromethane, chloroform, and combinations thereof. Alcohol solvents may be selected from the group consisting of: ethanol (EtOH), methanol, isopropanol, n-propanol, n-butanol, isobutanol, sec-butanol, pentanol (e.g., n-pentanol, isopentanol, and sec-pentanol), and combinations thereof. Alkyl carbonate solvents may be selected from the group consisting of: dimethyl carbonate, diethyl carbonate, dipropyl carbonate, and combinations thereof. Ketone solvents may include acetone. Hydrocarbon solvents may be selected from the group consisting of: hexane, pentane, cyclohexane, benzene, toluene, and combinations thereof. Ester solvents may include ethyl acetate. The ether solvent may be selected from the group consisting of: dimethyl ether, diethyl ether, tetrahydrofuran, dipropylene glycol dimethyl ether, methyl tert-butyl ether, glycol ether, and combinations thereof. Other solvents such as dimethylformamide, acetonitrile, N-methyl-2-pyrrolidone, dimethyl sulfoxide, or combinations thereof may also be used.

[0114] In some instances, the solvent comprises an aqueous solvent, is substantially composed of an aqueous solvent, or is composed of an aqueous solvent.

[0115] Mixtures of aqueous solvents and mixtures of organic solvents may be used. Mixtures of one or more aqueous solvents and one or more organic solvents may be used. The aqueous solvent or organic solvent may be considered as an alternative additive. For example, a relatively small amount of aqueous solvent may be used relative to the organic solvent. As another example, a relatively small amount of organic solvent may be used relative to the aqueous solvent.

[0116] The compositions described herein may further include additives. Additives may be used, for example, to improve the efficiency of the composition in absorbing or capturing CO2, increase the capacity of the composition in absorbing or capturing CO2, increase the rate at which the composition absorbs or captures CO2, or a combination thereof. Efficiency can be improved by adjusting the pH of the composition.

[0117] Illustrative but non-limiting examples of additives may include cyanuric acid, glycine, amino acids, diethylenetriamine (DETA), monoethanolamine (MEA), diethanolamine (DEA), 2-(diethylamino)ethanol (DEEA), N,N-dimethylcyclohexylamine (DMCA), 1,4-butanediamine (BDA), N-methyl-1,3-propanediamine, various liquid amines, organically dissolved amines, water-soluble amines, β-amino alcohols, serine alcohols, trihydroxyaminomethane (TRIS), and metal hydroxides (e.g., NaOH, KOH, Mg(OH)2). Ca(OH)2, Al(OH)2, Fe(OH)2), soluble metal salts (e.g., CuCl2, CuSO4, Cu(NO3)2, FeCl2, FeCl3, FeSO4, MgCl2, MgSO4), two-phase solvents (e.g., ionic liquids and various alcohols), lipophilic amines, polyethyleneamines (which may be branched or linear and have a weight-average molecular weight of about 100 g / mol to about 100,000 g / mol, e.g., PEI), amine-modified cellulose or chitin-based materials, sulfolane, metal-organic frameworks, or combinations thereof, etc.

[0118] Cyanuric acid can, for example, increase the capacity of the carbon dioxide adsorbent molecule to bind CO2. Glycine, for example, can, for example, increase the CO2 capture rate.

[0119] Metal-organic frameworks (MOFs) are inorganic-organic frameworks that can, for example, improve the capacity and / or efficiency of CO2 absorption. MOFs contain both a metal and an organic ligand. It is conceivable that the CO2 adsorbent molecule described herein may be in the form of a metal-organic framework, wherein the CO2 adsorbent molecule is an organic ligand. Additionally or alternatively, MOFs separate from the CO2 adsorbent molecule may be considered. Here, for example, a CO2 adsorbent molecule such as SMFG (described in the examples) can retain approximately 3 moles of CO2 per mole of adsorbent before saturation. The MOF acts like a bowl that can be filled with CO2, but it can also be filled with nitrogen (N2), so selectivity can be an issue. This can be attributed to the fact that most MOFs act more as mechanical or physical binders. Coupling SMFG (or other CO2 adsorbent molecules) to an MOF can help improve selectivity and capacity.

[0120] A suitable mixture of additives can be used in the compositions described herein.

[0121] Additionally or alternatively, and in some embodiments, CO2 capture or absorption can be enhanced by higher humidity conditions, controlled air or gas flow rates, or combinations thereof.

[0122] Compositions for absorbing, desorbing, or combining thereof for CO2 can be prepared by any suitable method. For example, the carbon dioxide adsorbent molecule can be appropriately mixed with optional solvents, optional additives, or combinations thereof.

[0123] Methods for forming carbon dioxide adsorbent molecules

[0124] Embodiments of this disclosure also generally relate to methods for forming carbon dioxide adsorbent molecules. The methods for synthesizing carbon dioxide adsorbent molecules can be carried out in any suitable reactor.

[0125] Unlike conventional techniques, this carbon dioxide adsorbent molecule can be prepared in an aqueous environment and in a one-pot reaction setup. The synthesis may also be solvent-free and produce less waste compared to current synthesis outlined in the literature. The product of this synthesis could be precipitated and concentrated (under vacuum) and then reconstituted in water for CO2 capture.

[0126] An illustrative but non-limiting reaction diagram for the synthesis of carbon dioxide adsorbent molecules is shown in Scheme 1. Scheme 1 is a non-limiting illustration of a one-pot synthesis that can be used to form carbon dioxide adsorbent molecules.

[0127] Option 1

[0128]

[0129] Although not shown in Scheme 1, a similar one-pot synthesis can be performed to achieve the purpose in which the dimethylene ether (-CH2-O-CH2-) bridges R 1 R 2 or R 3 One or more carbon dioxide adsorbent molecules coupled to melamine NH3. This synthesis can form a mixture of products comprising carbon dioxide adsorbent molecules having methylene bridges, dimethylene ether bridges, or combinations thereof.

[0130] In Scheme 1, (A) is melamine; (B) is a formaldehyde source; (C) is the reaction product of melamine and formaldehyde, i.e., melamine-formaldehyde or hydroxymethylated melamine; (D) represents a precursor material containing an ionizable functional group or a salt thereof (e.g., an ionizable functional group source, a salt source, or a polar non-ionizable functional group); (E) is the reaction product of (C) and (D), such as monosubstituted hydroxymethylated melamine; (F) represents a precursor material containing an organic amine (e.g., an organic amine source); and (G) is a non-limiting example of a carbon dioxide adsorbent molecule.

[0131] In some embodiments, operation 102 of scheme 1 includes reacting a mixture comprising melamine (represented by (A), a formaldehyde source (represented by (B)), and a catalyst to form the melamine-formaldehyde reaction product (represented by (C)). In some embodiments, the molar ratio of formaldehyde to melamine may be about 3:1. The catalyst may be a base catalyst, such as NaOH. The mixture used in operation 102 may also contain a solvent, such as water. In some embodiments, the reaction conditions of operation 102 may include reacting under alkaline conditions (e.g., setting the pH of the mixture to about 10.5 to 11) and heating the mixture at about 80°C for about 2 hours.

[0132] Besides formaldehyde, paraformaldehyde ((CH2O)) n Formalin (an aqueous solution of formaldehyde) can be used as a formaldehyde source. Alternatively or alternatively, formalin (an aqueous solution of formaldehyde) can be used as a formaldehyde source. Other aldehydes and ketones may also be considered.

[0133] Operation 104 of Scheme 1 may include reacting a mixture comprising the melamine-formaldehyde reaction product represented by (C) and an ionizable functional group source, or salt source, or organic amine source (in the form of, for example, the structures given in formulas (VK) to (VQ)) to form a reaction product represented by (E). The mixture may contain one or more additional components, such as solvents, other components, etc., depending, for example, on the reactants of Operation 104. The solvent may be water or an organic solvent. The reaction conditions of Operation 104 may depend on the ionizable functional group source, salt source, or organic amine source used. In some instances, the ionizable functional group source or salt source comprises sodium metabisulfite (Na₂S₂O₅). When sodium metabisulfite is used, the reaction conditions of Operation 104 may include reacting under alkaline conditions (e.g., setting the pH of the mixture to about 10.5-11) and heating the mixture at about 80°C for about 1 hour. Furthermore, when Na₂S₂O₅ is used, the reaction product (E) may be represented by formula (E-1):

[0134]

[0135] Operation 106 of Scheme 1 may include a non-limiting example of reacting a mixture comprising a reaction product represented by (E) and an organic amine source represented by (F) to form a carbon dioxide adsorbent molecule represented by formula (G). The mixture may contain one or more additional components, such as solvents, other components, etc., depending, for example, on the reactants of Operation 106. The solvent may be water or an organic solvent. The conditions and molar ratios of Operation 106 may depend on the reactants used in Operation 106. In some instances, the molar ratio of the organic amine source represented by (F) to the reaction product represented by (E) may be about 2:1. Various organic amine sources may be used, for example, according to the desired R group. Such R groups (e.g., R...) 1 and R2 As described above. In some embodiments, the organic amine source may comprise aminoguanidine (or a salt thereof), guanidine (or a salt thereof), amidourea (or a salt thereof), diethylenetriamine, PEI, or combinations thereof. Other organic amine sources may comprise amino acids (or salts thereof), polypeptides (or salts thereof), etc.

[0136] When using aminoguanidine hydrochloride (CAS No.: 1937-19-5), the reaction conditions of Operation 106 may include heating the reaction mixture at about 65°C to about 70°C for about 1.5 hours, and adjusting the pH from about 8.3 to about 7.4 during the reaction. Here, the pH may drift during the reaction. For example, adding aminoguanidine HCl lowers the pH to about 8.3, but as the material reacts, the pH drifts further down throughout the reaction until it reaches about 7.4. Furthermore, when using aminoguanidine hydrochloride as the organic amine source represented by (F), the carbon dioxide adsorbent molecule represented by (G) can be represented by formula (G-1):

[0137]

[0138] A 1 A 2 and A 3 As described above, as shown in formula (G-1), aminoguanidine can be coupled to melamine via a methylene bridge (-CH2-) and / or via a dialysyl ether (-CH2-O-CH2-) bridge. As also shown in formula (G-1), a salt group (or an ionizable functional group or a polar, non-ionizable functional group) can be coupled to melamine via a methylene bridge (-CH2-) or via a dialysyl ether (-CH2-O-CH2-) bridge.

[0139] In some embodiments, the ionizable functional group, its salt, or a polar non-ionizable group is coupled via a methylene bridge, and the organic amine is coupled via a methylene bridge or a dimethylene ether bridge.

[0140] Several variants of the synthesis for forming carbon dioxide adsorbent molecules are considered. These variants can be used to form different carbon dioxide adsorbent molecules that can be used in compositions for absorbing and / or desorbing CO2. Non-limiting variants may include one or more of the following variants:

[0141] Variant 1 Operation 104 is omitted, so that the carbon dioxide adsorbent molecule contains 3 organic amine groups.

[0142] Variant 2 Different organic amine sources can be used.

[0143] Variant 3First, aminoguanidine (AG) is reacted with formaldehyde (H₂CO) at a molar ratio of approximately 1:1 (HCHO:AG), at a pH of approximately 10⁻¹¹, and at a temperature of approximately 50°C to approximately 95°C to form a hydroxymethylated -AG reaction product. Then, melamine is added and reacted with the hydroxymethylated -AG at a molar ratio of approximately 1:1 to approximately 3:1 (hydroxymethylated -AG:melamine) at a temperature of approximately 40°C to approximately 95°C. The pH can be adjusted to pH = 5-10 to promote faster condensation. Solvents such as methanol, ethanol, or additional water can be added to improve solubility. Hydroxymethyl sulfonation may or may not be omitted. The final pH adjustment may or may not be omitted. Other organic amine sources and / or combinations of organic amine sources besides aminoguanidine (AG) can be used.

[0144] Variant 4 Melamine can be omitted to facilitate the direct condensation of AG with formaldehyde at a molar ratio of about 1:1 to about 2:1 (AG:HCHO) at a high pH, ​​followed by adjusting the pH to a lower level to further promote condensation. Here, the reaction product does not contain melamine. The reaction product does contain a formaldehyde source. This formaldehyde source can be a methylene bridge (-CH2-) or a dialysyl ether (-CH2-O-CH2-) bridge connecting AG to AG. The reaction product of this variant can be represented by formula (H-1) or (H-2), respectively, where the dashed arrows point to the methylene bridge of formula (H-1) and the dialysyl ether bridge of formula (H-2):

[0145]

[0146] Other organic amine sources and / or combinations of organic amine sources, besides aminoguanidine (AG) sources, may be used so that one or more different organic amine groups may be linked together via methylene bridges or dimethylene ether bridges.

[0147] Variant 5 Different monofunctional or polyfunctional nuclei or nuclear precursors can be used to replace the melamine-formaldehyde "nucleus". The "ligand" can be coupled to the nucleus. The nucleus and ligand molecule can be represented by formula (VI):

[0148] Nucleo-(ligand)q (VI)

[0149] Where: q in formula (VI) is the number of ligands bound to the nucleus. Here, the ligands (e.g., organic amine groups, ionizable functional groups (or their salts), or polar, non-ionizable functional groups, or combinations thereof) can be coupled to:

[0150] (a) Contains a core of polymeric amino and / or polymeric phenolic species. The organic amine group, ionizable functional group (or its salt), polar non-ionizable functional group, or combination thereof may be coupled to the polymeric amino and / or polymeric phenolic species via monoaldehyde, polyaldehyde, monoketone and / or polyketone as an organic amine.

[0151] (b) A core comprising a partially oxidized material having varying degrees of aldehyde and / or ketone functionality. The organic amine group, ionizable functional group (or its salt), polar non-ionizable functional group, or a combination thereof may be coupled to the core via aldehyde and / or ketone functionality.

[0152] (c) A nucleus containing a monocarboxylic acid species and / or a polycarboxylic acid species. The organic amine group, an ionizable functional group (or its salt), a polar non-ionizable functional group, or a combination thereof, may be coupled to the nucleus by condensation of the amine with the monocarboxylic acid or polycarboxylic acid species (through the elimination of water).

[0153] (d) A nucleus containing monohalogenated and / or polyhalogenated species. The organic amine group, ionizable functional group (or its salt), polar non-ionizable functional group, or combination thereof, may be coupled to the nucleus via the addition of the amine to the active site of the halocarbon, leading to the elimination of the halogen.

[0154] (e) A core comprising a monoepoxide species, a polyepoxide species, a monoglycidyl ether, and / or a polyglycidyl ether. The organic amine group, an ionizable functional group (or a salt thereof), a polar non-ionizable functional group, or a combination thereof may be coupled to the core via a reaction with the cyclic carbon of the epoxide (in Markovnikov or anti-Markovnikov addition).

[0155] (f) A nucleus containing a monoisocyanate species or a polyisocyanate species. The organic amine group, an ionizable functional group (or its salt), a polar non-ionizable functional group, or a combination thereof may be coupled to the nucleus by the isocyanate functional group to produce the resulting mono or polycarbamate species.

[0156] (g) A core comprising monoalkyl carbonate species, polyalkyl carbonate species, and / or polycyclic carbonate species. The organic amine group, ionizable functional group (or its salt), polar non-ionizable functional group, or a combination thereof, may be coupled to the core, for example, via a bis(dialkyl carbonate) route. This reaction can also be understood as a modified transurethanization, also known as transcarbamoylation. Ultimately, this may involve the reaction of a nucleophilic amine with an alkyl carbonate to produce an amide and eliminate the resulting alcohol such as MeOH, EtOH, or phenol. This reaction is more energy-efficient than the direct amide synthesis of amines and carboxylic acids.

[0157] (h) contains a combination of one or more of (a)-(g).

[0158] In some non-limiting examples, the "core" to which the organic amine group, ionizable functional group (or its salt), or combination thereof can be coupled may comprise phenol, urea, its derivatives, or combinations thereof. Here, depending on the starting material, the linkage between the organic amine group, ionizable functional group (or its salt), or combination thereof may be methylene, dimethylene ether (-CH2-O-CH2-), amide, urethane, as an RCN bond, or combinations thereof. For example, the core may comprise phthalic acid, isocyanate, and / or other polyacids instead of melamine-formaldehyde to link the organic amine group.

[0159] Further variants of the materials listed above may include various substituted linear or branched aliphatic, linear or branched cycloaliphatic, monoalkenyl or polyalkenyl species, as well as various substituted monoaromatic or polyaromatic species. Mixtures of these species may exist in aqueous or solvent-based environments.

[0160] Any suitable variants may be considered for combination with other variants to form alternative variants and alternative carbon dioxide adsorbent molecules.

[0161] The various carbon dioxide adsorbent molecules and their compositions described herein, whether in solution or solid form, are applicable to a wide range of applications, including but not limited to direct air capture (DAC) for carbon capture and storage (CCS) and / or carbon capture, storage and utilization (CCSU).

[0162] Methods for capturing and releasing CO2

[0163] Embodiments of this disclosure also generally relate to methods for capturing (absorbing) and / or releasing (desorbing) CO2 using the compositions described herein. During absorption and / or desorption, one or more components of the composition may be present as ions (one or more). The absorption and desorption methods can be carried out in any suitable reactor.

[0164] Typically, methods for absorbing CO2 may include introducing a CO2-containing gas stream or gas source together with the composition described herein; and forming a CO2-enriched composition. In some embodiments, the composition contains a solvent such as water or other suitable solvent. Additionally or alternatively, the composition contains solid carbon dioxide adsorbent molecules. Additives may be incorporated into the composition if desired.

[0165] In some embodiments, the CO2 enrichment composition comprises CO2 bound to the carbon dioxide adsorbent molecule. In some embodiments, the bound CO2 may be carbonate (CO3-). 2- ), bicarbonate (HCO3) -In at least one embodiment, the CO2 bound to the carbon dioxide adsorbent molecule is in the form of a salt. The salt may comprise a cation containing the carbon dioxide adsorbent molecule; and an anion containing carbonate (CO3) ions. 2- ), bicarbonate (HCO3) - (or combinations thereof). The salt may optionally contain cations such as sodium, potassium, or ammonium.

[0166] In some embodiments, the method for capturing CO2 includes contacting a gas stream or gas source containing CO2 with carbon dioxide adsorbent molecules (or a combination thereof) and precipitating a complex containing CO2 bound to the carbon dioxide adsorbent molecules. In some embodiments, the composition contains a solvent such as water or other suitable solvent. Additionally or alternatively, the composition contains solid carbon dioxide adsorbent molecules. Additives may be incorporated into the composition if desired.

[0167] In some embodiments, the complex comprises CO2 bound to the carbon dioxide adsorbent molecule. The bound CO2 may be carbonate (CO3-). 2- ), bicarbonate (HCO3) - In at least one embodiment, the CO2 bound to the carbon dioxide adsorbent molecule is in the form of a salt. The salt may comprise a cation containing the carbon dioxide adsorbent molecule; and an anion containing carbonate (CO3) ions. 2- ), bicarbonate (HCO3) - (or combinations thereof). The salt may optionally contain cations such as sodium, potassium, or ammonium.

[0168] During the absorption operation, the carbon dioxide adsorbent molecules can bind CO2 directly from the air under ambient conditions by bubbling air through a solution containing any suitable amount of carbon dioxide adsorbent molecules. Additionally or alternatively, ambient air can be passed over a solid adsorbent containing carbon dioxide adsorbent molecules under ambient air conditions. Absorption conditions may include ambient conditions or elevated temperature conditions, such as temperatures below about 120°C, for example, temperatures below about 110°C. Absorption conditions may optionally include a high humidity environment.

[0169] In some embodiments used for CO2 absorption, the carbon dioxide adsorbent molecule can be used in a flue gas environment.

[0170] The CO2 absorbed, captured, or stored by the methods described herein can bind to the carbon dioxide adsorbent molecule in any suitable manner (e.g., through physical binding, chemical binding, or a combination thereof). In some instances, the absorbed, captured, or stored CO2 can exist in various forms. In some embodiments, the bound CO2 can be carbonate (CO3-). 2- ), bicarbonate (HCO3) - (or combinations thereof). Here, and in some instances, and after the carbon dioxide adsorbent molecule is exposed to CO2, a complex comprising the carbon dioxide adsorbent molecule and CO2 can be formed, wherein the complex may comprise carbonate and / or bicarbonate anions (from CO2) and a cation of the carbon dioxide adsorbent molecule. Additionally or alternatively, and in some instances, the complex may comprise carbonate and / or bicarbonate anions (from CO2) and a cation of the carbon dioxide adsorbent molecule, as well as monovalent cations such as sodium, potassium, or ammonium. The complex may be a salt.

[0171] Additionally or alternatively, carbon dioxide can form chemical bonds with the carbon dioxide adsorbent molecule. Such chemical bonds may include urethane (urethane) bonds, depending on, for example, the capture conditions. Additionally or alternatively, carbon dioxide can physically bind with the carbon dioxide adsorbent molecule, for example, through electrostatic interactions such as van der Waals forces.

[0172] CO2 encapsulated by one or more components of the composition described herein may be carbonate (CO3-) 2- Salt, bicarbonate (HCO3) - The salt, the reaction product of one or more components of the composition (e.g., urethane), or CO2 physically bound by electrostatic interactions (e.g., van der Waals forces), or combinations thereof.

[0173] After capturing CO2 using the methods described herein, CO2 can be desorbed or released. In some embodiments, the CO2 enrichment composition or a complex containing CO2 bound to the carbon dioxide adsorbent molecule can be subjected to desorption conditions to remove CO2 and regenerate the carbon dioxide adsorbent molecule. Desorption conditions may include heat, acidic conditions, alkaline conditions, hydrolysis, electrolysis, electromagnetic radiation, ion exchange, increased pressure, vacuum pressure, or combinations thereof. In at least one embodiment, the desorption conditions are heat, vacuum pressure, or combinations thereof. Desorption of CO2 from the CO2 enrichment composition or a complex containing CO2 bound to the carbon dioxide adsorbent molecule can form a CO2-depleted composition.

[0174] Compared to conventional techniques (e.g., metal hydroxides), desorption can occur at low temperatures, such as about 30°C to about 250°C, 50°C to about 225°C, about 75°C to about 200°C, about 100°C to about 175°C, about 110°C to about 160°C, less than about 160°C, or about 120°C to about 130°C, or about 100°C to about 120°C, such as about 105°C, or about 40°C to about 160°C, although other values ​​are also considered. Any of the above figures can be used alone to describe an open range or in combination to describe a closed range.

[0175] Furthermore, the embodiments described herein can achieve low-temperature desorption, for example, below about 160°C. In some non-limiting examples, desorption can be carried out at a temperature of about 105°C. In other non-limiting examples, the desorption temperature can be from about 120°C to about 130°C.

[0176] In some implementations, the removed CO2 may be isolated for storage, converted into chemicals or feedstocks, or combinations thereof, and used for other purposes. Applications and uses are further described below.

[0177] The embodiments disclosed herein also typically relate to the application or use of the embodiments. For example, the carbon dioxide adsorbent molecules and / or compositions thereof described herein, whether in solution or solid form, can be used for carbon capture and storage (CCS) and / or carbon capture, storage and utilization (CCSU).

[0178] Illustrative but non-limiting applications or uses include: direct air capture; CO2 capture from flue gas emissions; desorption of CO2 and subsequent reaction with calcium hydroxide solution to prepare calcium carbonate (CaCO3) for carbon capture and storage (CCS); enhanced oil recovery (EOR) for CCSU; desorption and concentration of CO2 for reaction with a metal catalyst for methanol production, which can be used to prepare formaldehyde useful in various technologies such as adhesives (CCSU); desorption and concentration of CO2 to synthesize alkyl carbonates, which can be used in polyurethane technology (CCSU); use as a flame retardant or flame retardant additive (CCSU); use as an agricultural amendment, as a gaseous CO2 or soil additive (CCSU); or use as a concrete additive to prevent CO2 release during curing (CCS). Other applications are also considered.

[0179] The embodiments described herein offer various advantages. Unlike conventional techniques, the carbon dioxide adsorbent molecules described herein can be synthesized in an aqueous environment and in a one-pot reaction configuration. The synthesis may also exclude filtration operations. The synthesis may also be solvent-free and generate less waste compared to current synthesis outlined in the literature. In some embodiments, the product of the synthesis can be precipitated and concentrated (under vacuum) to obtain 100% solids, and then reconstituted in water.

[0180] Furthermore, compared to some materials currently available on the market (such as metal hydroxide scavengers like NaOH and KOH), the carbon dioxide adsorbent molecules described herein are capable of desorbing CO2 at relatively low temperatures. In contrast, these metal hydroxide scavengers require a significant energy investment to completely boil away the water, followed by temperatures in the range of 900°C to 1,000°C to desorb CO2.

[0181] The following embodiments are provided to provide those skilled in the art with a complete disclosure and illustration of how to implement and use embodiments of this disclosure, and are not intended to limit the scope of embodiments of this disclosure. Efforts have been made to ensure the accuracy of the figures used, but some experimental errors and biases should be taken into account.

[0182] Example

[0183] Example 1: Synthesis of carbon dioxide adsorbent molecules

[0184] Scheme 2 is a non-limiting one-pot synthesis that can be used to form carbon dioxide adsorbent molecules. In this non-limiting embodiment, the carbon dioxide adsorbent molecule is the reaction product of aminoguanidine and melamine-formaldehyde adduct.

[0185] Option 2

[0186]

[0187] Here, a mixture containing melamine (A-1), formaldehyde (B-1), and NaOH is reacted at 80°C for 2 hours to form a melamine-formaldehyde adduct or reaction product (C-1). This operation is an example of operation 102. The reaction is carried out at a pH of 10.5-11, with a molar ratio of formaldehyde to melamine of 3:1.

[0188] A mixture comprising a melamine-formaldehyde adduct or reaction product (C-1) and sodium metabisulfite (Na₂S₂O₅) is reacted at 80°C for 1 hour to form a monosubstituted melamine-formaldehyde reaction product (E-1). This operation is an example of operation 104. Na₂S₂O₅ is an example of an ionizable functional group source or salt source. The use of Na₂S₂O₅ helps to maintain the pH range without causing the decomposition of the melamine-formaldehyde adduct.

[0189] A mixture comprising a monosubstituted melamine-formaldehyde reaction product (E-1) and aminoguanidine (F-1) is reacted at a temperature of 65°C to 70°C for 1.5 hours to form a product mixture comprising an exemplary carbon dioxide adsorbent molecule (G-1a). This operation is an example of operation 106. Aminoguanidine is an example of an organic amine source. For this reaction, aminoguanidine hydrochloride (aminoguanidine-HCl) is used. The molar ratio of aminoguanidine to the substituted melamine-formaldehyde reaction product is 2:1. During the reaction, the pH is allowed to drift from 8.3 to 7.4 to promote the reaction.

[0190] It has been found that product mixtures containing the exemplary carbon dioxide adsorbent molecule (G-1a) may also contain exemplary carbon dioxide adsorbent molecules (G-1b), exemplary carbon dioxide adsorbent molecules (G-1c), their ions, or combinations thereof:

[0191]

[0192] .

[0193] Therefore, and in some instances, exemplary carbon dioxide adsorbent molecules (sulfonated melamine-formaldehyde-aminoguanidine (SMFG)) contain one or more of G-1a, G-1b, G-1c or their ions, as shown below:

[0194]

[0195] Among them: A 1 It is CH2 or CH2OCH2; and A 2 It is CH2 or CH2OCH2.

[0196] Figure 1 DEPT- of product SMFG is shown. 13 CNMR. DEPT- was performed on the final product. 13CNMR experiments were conducted to help elucidate the structural identity of the SMFG adduct. The sample was pulsed at 45°, 90°, and 135°. As seen in the 135° pulse sequence, almost every carbon shift was inverse, producing a negative peak. The pulse sequence at 45° yielded in-phase chemical shifts, producing positive peaks, while the pulse sequence at 90° showed in-phase chemical shifts, but significantly attenuated. Chemical shifts between approximately 45 ppm and approximately 140 ppm should have disappeared in the 90° spectrum. Their incomplete disappearance is likely due to instrument tuning. The overall spectrum suggests that the linker may contain a methylene carbon (-CH2-), and, according to the literature, appears to be consistent with a dimethylene ether linker (-CH2-O-CH2-) in the range of approximately 60–75 ppm, although the true methylene linker (-CH2-) is observable in the range of 40–60 ppm. Regarding… Figure 1 The products SMFG shown in the bottom subplot are chemically assigned as follows: D6-DMSO (approximately 40 ppm); sulfonated hydroxymethyl (approximately 56 ppm); bicarbonate carbon (approximately 156 ppm); hydroxymethylated aminoguanidine (approximately 159 ppm); and the reaction product of hydroxymethylated melamine (approximately 167 ppm).

[0197] A chemical shift of approximately 140 ppm occurs after the addition of aminoguanidine and after the synthesis is complete. Here, the peak initially appears at approximately 140 ppm in stage 3 (after aminoguanidine) (see [link to previous text]). Figure 3 (as discussed in the previous section), and then shifted to about 138 ppm in stage 4. D6-DMSO had a chemical shift of about 40 ppm, and the internal standard (pyrazine) had a chemical shift of about 145 ppm.

[0198] Another exemplary carbon dioxide adsorbent molecule, melamine-formaldehyde-guanidine (MFG), was synthesized in a similar manner. Sulfonation was not performed, and guanidine was used as the organic amine. This organic amine source could be guanidine carbonate (guanidine-CO3). 2- (salts) and / or guanidine hydrochloride (guanidine-HCl). MFG is represented by G-2:

[0199] .

[0200] Product mixtures containing the exemplary carbon dioxide adsorbent molecule (G-2) may also contain carbon dioxide adsorbent molecules having methylene bridges, dimethylene ether bridges, or combinations thereof.

[0201] The active molecules (the exemplary carbon dioxide adsorbent molecule) can bind CO2 directly from the air under ambient conditions by bubbling air through an activated solution of variable concentration. Additionally, ambient air can pass over the solid adsorbent under ambient or extreme conditions at temperatures below approximately 110°C and in the presence of high humidity. The material can also be used in flue gas environments.

[0202] Example 2: CO2 absorption and CO2 desorption

[0203] 2.A. SMFG carbon dioxide adsorbent molecule

[0204] Figure 2 This is a superimposed image of the Fourier transform mid-infrared (FT-MIR) spectra of CO2 absorption via SMFG. The spectra have been normalized and baseline corrected. The superimposed image includes the SMFG reaction precipitate formed at the end of the reaction (sample S1-1), the precipitate formed by bubbling CO2 through the SMFG solution (sample S1-2), and the precipitate formed once the filtrate comes into contact with the wash water (sample S1-3). Commercially available aminoguanidine bicarbonate from Sigma Aldrich was used as a control (sample S1-4). The asymmetric stretching of carbonate CO2 by [the following data is missing from the original text] is at approximately 1270 cm⁻¹. -1 Approximately 1400cm -1 The part in brackets indicates that the carbon dioxide adsorbent molecule bound to CO2 can exist as a carbon dioxide adsorbent molecule-CO2 complex. When bound to an aminoguanidine adduct, the bound CO2 in the complex can be, for example, HCO3-. - and / or CO3 2- It exists in the form of [unclear]. Overall, the results indicate that CO2 is absorbed by SMFG, as shown by the stretching and contraction of carbonate (CO).

[0205] Figure 3 Various materials produced and used during the synthesis of SMFG 13 A stacked image of C NMR spectra. Figure 3 The synthesis process is illustrated in the figure, including: hydroxymethylation of melamine (stage 1); sulfonation of hydroxymethylated melamine to form sulfonated melamine-formaldehyde (SMF) (stage 2); co-reaction of aminoguanidine-HCl with SMF (stage 3); and the final product SMFG at pH 10 (stage 4). Figure 3 of 13 The chemical shifts of carbon atoms in the C NMR spectra (indicated by arrows) are shown in Table 1.

[0206] Table 1

[0207]

[0208] Regarding substituted and unsubstituted melamine (as well as hydroxymethylated and sulfonated melamine) 13 The C10 NMR spectrum shows no dramatic shifts in the peaks at approximately 167 and 168 ppm. This is likely due to the fact that these carbon environments (-C=N-; imine) are "locked" within the triazine ring structure and are only slightly affected by substituents on adjacent amines. These chemical shift values ​​correspond only to carbons in the ring and not to the hydroxymethyl group itself.

[0209] Overall, 13 C10 NMR data confirmed that the reaction of melamine and formaldehyde produces hydroxymethylated melamine, confirmed the sulfonation of hydroxymethylated melamine, and confirmed that the reaction of aminoguanidine with SMF forms SMFG carbon dioxide adsorbent molecules.

[0210] TGA was performed to characterize the absorbed CO2. Figure 4 TGA data for SMFG-CO2 (sample S2-1), aminoguanidine bicarbonate (sample S2-2) are shown as controls, and glyoxal-bis-iminoguanidine-CO2 (GBIG-CO2; sample S2-3) is shown as a reference. Figure 4 The results shown were obtained by testing samples under atmospheric conditions using a heating ramp method from 25°C to 300°C at a rate of 5°C / min. Table 2 shows the percentage of mass loss from the TGA experiment and the theoretical percentage of mass loss for samples S2-1, S2-2, and S2-3. SMFG-CO2 (sample S2-1) has an unknown hydration state. GBIG-CO2 (sample S2-3) has a 4-hydration state, which is GBIG-CO2·4H2O.

[0211] Table 2

[0212]

[0213] Overall, Figure 4The results shown in Table 2 indicate that CO2 is adsorbed onto the exemplary carbon dioxide adsorbent molecules. When comparing the percentage mass loss of SMFG with the aminoguanidine bicarbonate and GBIG references, molecular weight should be considered. The higher molecular weight of SMFG compared to both GBIG and aminoguanidine bicarbonate results in a lower total mass loss with CO2 evacuation. This data also indicates the presence of decomposition of the aminoguanidine bicarbonate and GBIG references. Here, the reference material GBIG appears to decompose at approximately 245 °C, and aminoguanidine bicarbonate appears to decompose at approximately 200 °C. Melamine itself begins to decompose at approximately 300 °C. Although decomposition of SMFG is difficult to characterize (as TGA shows a very gentle downward slope), decomposition of SMFG is likely to occur at approximately 245 °C. In any case, the decomposition temperature of SMFG (likely around 245 °C) is higher than the desorption temperature.

[0214] Figure 5A and Figure 5B Data for the analysis of escape gases from GBIG-CO2 and SMFG-CO2 are shown separately. Carbon dioxide was desorbed from SMFG-CO2 at atmospheric pressure using a heating ramp method from 25°C to 300°C at a rate of 5°C / min. The escaped gas was then passed through FT-IR to detect the presence of CO2. Figure 5B This indicates that CO2 has been thermally desorbed from the newly synthesized SMFG molecules. Compared to GBIG, the newly synthesized SMFG material shows an improved degree of CO2 escape. Overall, the results demonstrate that CO2 can be desorbed from the SMFG-CO2 complex.

[0215] Figure 6 Data showing the change in mass increase of an exemplary carbon dioxide adsorbent molecule over CO2 absorption time according to at least one embodiment of this disclosure are presented. For Figure 6 The data shown were used to conduct the following experiment: 42.16 g of a 9.98% SMFG solution was transferred to a collision sampler, and CO2 gas was purged through a porous glass aerosphere. The CO2 gas reacted with the SMFG to form a precipitate within 30 seconds. Table 3 shows the selected data for the experiment.

[0216] Table 3

[0217]

[0218] like Figure 6 As shown in Table 3, after approximately 5 minutes of exposure to CO2 gas, the mass of SMFG acquired was approximately 1.48 g. This result is associated with approximately 0.35 g of CO2 per 1 gram of SMFG adsorbent and approximately 3.3 moles of CO2 per 1 mole of SMFG adsorbent. The theoretical molecular weight of the SMFG adsorbent is calculated to be approximately 414.38 g / mol. Figure 6The results shown also demonstrate the excellent efficiency of the SMFG adsorbent. The reduction in mass obtained is likely due to water evaporation.

[0219] 2.B. MFG carbon dioxide adsorbent molecules

[0220] A guanidine derivative (MFG, G-2, 4.7 wt%) was used in this example. The solution appeared clear before exposure to CO2. After exposure to CO2, the solution became cloudy, indicating precipitation and CO2 binding to the adsorbent MFG.

[0221] Figure 7 It refers to the various materials produced and used during the synthesis of MFG (G-2). 13 A superimposed C NMR spectrum. It shows the various stages of synthesis, including: the hydroxymethylation stage involving melamine hydroxymethylation (Stage 1); guanidine-CO3... 2- The co-reaction of salt with hydroxymethylated melamine, t = 0 h (stage 2); the co-reaction of guanidine-HCl salt with hydroxymethylated melamine, t = 2 h (stage 3); and the final product MFG after distillation (stage 4). The spectrum of stage 2 shows the reaction of guanidine bicarbonate with hydroxymethylated melamine at t = 0 h. The carbonate was acidified with excess formic acid to decompose the carbonate into CO2 and the pH was adjusted to a lower level to promote the condensation of hydroxymethylated melamine into guanidine. Figure 7 of 13 The approximate chemical shifts of carbon atoms in the C NMR spectra (indicated by arrows) are shown in Table 4.

[0222] Table 4

[0223]

[0224] on the whole, 13 C10 NMR data confirmed that the reaction of melamine and formaldehyde produces hydroxymethylated melamine, and also confirmed that the reaction of guanidine with hydroxymethylated melamine forms MFG carbon dioxide adsorbent molecules.

[0225] Figure 8This is a superimposed FT-MIR spectrum showing the desorption of CO2 by an exemplary carbon dioxide adsorbent molecule (MFG, G-2). For this experiment, CO2 was desorbed from the MFG-CO2 complex at 105 °C under full vacuum. Sample S3-1 refers to the MFG before CO2 capture (MFG at time (t) = 0 min), and sample S3-2 refers to the CO2 bound to the MFG-CO2 complex, and sample S3-3 refers to the MFG obtained after heating the MFG-CO2 complex at 105 °C under full vacuum (MFG reactivation). Sample S3-4 refers to the guanidine-carbonate control used as a reference for bound CO2. Sample S3-5 refers to the guanidine-HCl control used as a reference for no CO2 binding. The carbonate CO asymmetric stretching was observed at approximately 1350 cm⁻¹. -1 Approximately 1400cm -1 The line at the point is enclosed in brackets.

[0226] At time 0 minutes, MFG was not yet exposed to CO2 (sample S3-1). Upon exposure to CO2, an MFG-CO2 complex was formed (sample S3-2). MFG was regenerated after thermal desorption (sample S3-3). Overall, the results indicate that CO2 can be absorbed by the CO2 adsorbent molecules described herein. The results also show that the CO2 adsorbent molecules described herein can be regenerated by subjecting the complex containing CO2 bound to the CO2 adsorbent molecules to desorption conditions. As shown, the desorption conditions can be mild and can be carried out at low temperatures. Overall, the CO2 adsorbent molecules described herein are recyclable and can be reused for further CO2 capture and release.

[0227] Figure 9 The FT-MIR spectra of carbon dioxide desorbed from the MFG-CO2 complex (top subplot) and CO2 alone (bottom subplot) are shown. For Figure 9 The data shown in the top subplot involves acidifying the MFG-CO2 complex, performing headspace sampling, and then injecting that headspace into an FT-MIR. The reference FT-MIR spectrum for CO2 (bottom subplot) is obtained from the National Institute of Standards and Technology (NIST) of the U.S. Department of Commerce. The spectra shown in the top and bottom subplots are not on the same scale.

[0228] Acidification of the MFG-CO2 complex leads to the release (desorption) of CO2, such as from approximately 2350 cm⁻¹. -1 The absorption peaks at the specified locations indicate that CO2 can be desorbed from complexes containing CO2 bound to the carbon dioxide adsorbent molecules of this disclosure.

[0229] Example 3. Evaluation of carbon dioxide adsorbent molecules

[0230] Table 5 shows a comparison of exemplary carbon dioxide adsorbent molecules and comparative adsorbents. SMFG was prepared as an approximately 10% solid solution (sample S4-1), and MFG as a 4.7% solid solution (sample S4-2). Comparative examples include a 0.01 M solution of 1,3,5-benzenetris(iminoguanidine) (BTIG, sample S4-3), a 30% monoethanolamine (MEA) solution (sample S4-4), a 1 M sodium hydroxide (NaOH) aqueous solution (sample S4-5), 2,6-pyridine-bis(iminoguanidine) (sample S4-6), and a melamine-formaldehyde (MF) nanoporous network (sample S4-7).

[0231] Table 5

[0232]

[0233] Overall, the data in Table 5 demonstrate that the embodiments of this disclosure are significantly superior to conventional CO2 adsorbents. For example, while the comparative examples (samples S4-3 to S4-7) show that a maximum of 1.46 moles of CO2 can be absorbed per mole of adsorbent, it has been determined that the exemplary SMFG adsorbent can absorb more than twice that amount (sample S4-1: 3.31 moles of CO2 per mole of MFG adsorbent) and the exemplary MFG adsorbent can absorb more than three times that amount (sample S4-2: 3.89-4.94 moles of CO2 per mole of MFG adsorbent).

[0234] The exact number of moles of CO2 per gram of adsorbent depends on the molecular weight of the adsorbent. For example, 1 gram of SMFG is approximately 0.0025 moles, while 1 gram of NaOH is 0.025 moles. Using NaOH as an adsorbent (10 times the molar amount) only achieves about 1.4 times more CO2 absorption than SMFG. Overall, smaller molar amounts of SMFG and MFG perform more work than conventional adsorbents. It is also noted that BTIG (Comparative Example 1) is a trichelate ligand, where CO2 can complex with three guanidine binding portions, while SMFG and MFG contain only two ligands that can bind or complex CO2.

[0235] Example 4: CO2 capture: Adsorbent recyclability

[0236] The recyclability of the adsorbent was tested in multiple carbon dioxide gas absorption-desorption cycles. For this example, the adsorbent was prepared according to the following procedure: glyoxal (40% aqueous solution, Sigma Aldrich, CAS No. 107-22-2) and amidourea sulfate (TCI, CAS No. 591-01-5) were reacted in ethanol at 65°C for 4 hours in a 2:1 molar ratio. The reactants were washed with ethanol and diethyl ether and dried to obtain the resulting carbon dioxide adsorbent molecules as a white solid powder. The synthesized adsorbent comprises a mixture of the following substances:

[0237] and .

[0238] 32g of the synthesized adsorbent molecules were mixed with water to form an aqueous solution of approximately 12% by weight. Free base was prepared by adding 50% by weight caustic solution (NaOH) to displace all sulfate ions from the adsorbent molecules and make them usable for carbon capture. The addition of the caustic solution dissolved the adsorbent molecules in water. Sufficient caustic solution was added to achieve a pH of 12-13 before bubbling with a pure CO2 gas stream. The liquid free base was transferred to a collision sampler connected to a CO2 cylinder.

[0239] Absorption-desorption cycle 1

[0240] Absorption 1: Pure CO2 was bubbled at approximately 0.45 standard liters per minute (SLPM), and the mass increase was monitored every 10 minutes. Bubbling was stopped once no further mass increase was observed. Part of the CO2 was absorbed by the adsorbent and part by the caustic solution. The adsorbent molecules and caustic solution absorbed CO2 within 2-3 minutes of bubbling to form a white, cloudy slurry in the water. A total of approximately 7.94 g of CO2 was absorbed during the total bubbling time of 74 minutes. Figure 10 Theoretically, each adsorbent molecule has two active sites for CO2 absorption. The slurry was filtered, and the residue was washed with water and dried in ambient air to obtain 15.96 g of adsorbent-CO2 complex as a solid coarse powder, light beige in color. TGA-MIR confirmed a weight loss of approximately 29.4% (originating from the combination of water and CO2) when the adsorbent-CO2 complex was exposed to a temperature ramp. TGA data also indicated that the weight loss began at approximately 62 °C, and the maximum loss occurred between approximately 90 °C and approximately 100 °C.

[0241] Desorption 1: 8 g of the adsorbent-CO2 complex was placed in a vacuum oven at 80°C under full vacuum (-42 cmHg). A 25.25% weight loss of the adsorbent-CO2 complex was observed after 28 minutes in the vacuum oven, providing a yield of approximately 5.98 g after desorption. For the absorption-desorption experiment, complete desorption was not performed (until a 29.4% weight loss was observed).

[0242] Absorption-desorption cycle 2

[0243] 5.77 g of regenerated adsorbent was added to water to prepare an aqueous slurry of approximately 12 wt%. 50 wt% caustic solution was added to dissolve the regenerated adsorbent. CO2 was bubbled at approximately 0.45 SLPM for 76 minutes, with a total CO2 absorption of approximately 3.4 g. The solution became turbid within 1 minute of bubbling. The slurry was filtered, and the resulting residue was washed with water and dried in ambient air to obtain 4.18 g of adsorbent-CO2 complex in powder form. TGA data for the adsorbent-CO2 complex showed that desorption began again at approximately 62 °C, but the maximum weight loss shifted slightly to the right and occurred between 100 °C and 110 °C. A 28% weight loss was observed after 46 minutes in a vacuum oven (at 80 °C and -42 cmHg).

[0244] Absorption-desorption cycle 3

[0245] The same process as described in the previous cycle was performed. Here, the regenerated adsorbent obtained from cycle 2 was converted into free alkali before CO2 bubbling. The slurry was filtered, and the resulting residue was washed with water and dried in ambient air to obtain an adsorbent-CO2 complex in powder form. Further absorption-desorption cycles can then be performed.

[0246] The embodiments described herein generally relate to carbon dioxide adsorbent molecules and methods for forming carbon dioxide adsorbent molecules. The embodiments described herein also generally relate to methods for CO2 absorption and CO2 desorption. For CO2 absorption and CO2 desorption, the carbon dioxide adsorbent molecules can be in solution form or in a solid state. The embodiments described herein are superior to conventional CO2 capture technologies. Furthermore, the carbon dioxide adsorbent molecules can be regenerated and recycled for further use after CO2 desorption.

[0247] Implementation Plan List

[0248] This disclosure provides for the following and other aspects, each of which may be considered to optionally include any alternative implementation:

[0249] Clause 1. A composition for absorbing or desorbing carbon dioxide (CO2), the composition comprising a carbon dioxide adsorbent molecule comprising a melamine-formaldehyde adduct or reaction product modified with an organic amine source, the organic amine source being different from the melamine.

[0250] Clause 2. A composition for absorbing or desorbing carbon dioxide (CO2), the composition comprising: a carbon dioxide adsorbent molecule comprising a reaction product of: (a) an organic amine source; and (b) a reaction product of melamine and formaldehyde, wherein the organic amine source is different from the melamine.

[0251] Clause 3. A composition for absorbing or desorbing carbon dioxide (CO2), the composition comprising a carbon dioxide adsorbent molecule, the carbon dioxide adsorbent molecule comprising:

[0252] The core comprises polymeric amino species, polymeric phenolic species, partially oxidized materials with aldehyde functionality, partially oxidized materials with ketone functionality, monocarboxylic acid species, polycarboxylic acid species, monohalogenated species, polyhalogenated species, monoepoxide species, polyepoxide species, monoglycidyl ether, polyglycidyl ether, monoisocyanate species, or polyisocyanate species, monoalkyl carbonate species, polyalkyl carbonate species, or combinations thereof; and

[0253] One or more ligands chemically bonded to the nucleus, at least one of the one or more ligands comprising an organic amine group.

[0254] Clause 4. The composition of any of the preceding clauses, wherein the carbon dioxide adsorbent molecule further comprises an ionizable functional group, its salt, a polar non-ionizable functional group, or a combination thereof, wherein the ionizable functional group, its salt, and the polar non-ionizable functional group are different from the melamine and the organic amine source.

[0255] Clause 5. The composition of any of the preceding clauses further comprises an aqueous solvent, an organic solvent, or a combination thereof.

[0256] Clause 6. The composition of any of the preceding clauses further comprises one or more additives.

[0257] Clause 7. The composition of any of the preceding clauses, wherein the carbon dioxide adsorbent molecule is represented by formula (IA):

[0258]

[0259] in:

[0260] A 1 A 2 and A 3Each of them is independently CH2 or CH2OCH2; and

[0261] R of formula (IA) 1 R 2 and R 3 Each of them is independently hydrogen, an unsubstituted hydrocarbon group, a substituted hydrocarbon group, or a functional group containing at least one element from Groups 13-17 of the periodic table.

[0262] Clause 8. The composition of Clause 7, wherein R of formula (IA) 1 R 2 Or R 3 One or more of them are organic amine groups.

[0263] Clause 9. The composition of Clause 8, wherein:

[0264] When one or more R of equation (IA) 1 R 2 Or R 3 When the group is an organic amine group, the organic amine group is selected from the group consisting of: primary amines, secondary amines, tertiary amines, polyamines, imines, carbamates, polyimides, Schiff bases, amines capable of forming imines, amines capable of forming Schiff bases, amino acids, polypeptides, or combinations thereof; and

[0265] When R of equation (IA) 1 R 2 Or R 3 When two or more of the components are organic amine groups, each organic amine group may be the same or different.

[0266] Clause 10. A composition of any one of Clauses 7-9, wherein:

[0267] R of formula (IA) 1 R 2 Or R 3 At least one of them is an ionizable functional group, its salt, or a polar non-ionizable functional group; and

[0268] The ionizable functional group, its salt, or the polar non-ionizable functional group are different from the melamine and the organic amine group.

[0269] Clause 11. The composition of Clause 10, wherein the ionizable functional group comprises sulfate, sulfonate, phosphate, phosphonate, carboxylic acid, or a combination thereof.

[0270] Clause 12. The composition of any one of Clauses 10 or 11, wherein the salt of the ionizable functional group comprises:

[0271] The anion of the ionizable functional group; and

[0272] The cation includes alkali metals, alkaline earth metals, transition metals, ammonium, alkylammonium, and pyridine. , or a combination thereof.

[0273] Clause 13. The composition of any of the preceding clauses, wherein the carbon dioxide adsorbent molecule comprises one or more of the following:

[0274]

[0275]

[0276]

[0277] Where: each X + When present, it is independently an alkali metal, alkaline earth metal, transition metal, ammonium, alkylammonium, or pyridine. , or a combination thereof.

[0278] Clause 14. The composition of any of the preceding clauses, wherein the carbon dioxide adsorbent molecule comprises one or more of the following:

[0279]

[0280] or

[0281]

[0282] Where: X + When present, it is an alkali metal, alkaline earth metal, transition metal, ammonium, alkylammonium, or pyridine. , or combinations thereof; and each x, y, and z in the formula is independent when it exists.

[0283] Clause 15. A method for forming carbon dioxide adsorbent molecules, the method comprising:

[0284] Hydroxymethylated melamine is formed by reacting a first mixture containing melamine and a formaldehyde source.

[0285] A second mixture comprising the hydroxymethylated melamine and an ionizable functional group source, a salt group source, a polar non-ionizable functional group source, or a combination thereof, is reacted to form a monosubstituted hydroxymethylated melamine, wherein the ionizable functional group source, the salt group source, and the polar non-ionizable functional group source are different from the melamine; and

[0286] The hydroxymethylated melamine containing the monosubstituted melamine is reacted with an organic amine source to form a carbon dioxide adsorbent molecule, the organic amine source being different from the melamine, the ionizable functional group source, the salt group source, and the polar non-ionizable functional group source.

[0287] Clause 16. The method of Clause 15, wherein the carbon dioxide adsorbent molecule comprises any one of the carbon dioxide adsorbent molecules of Clauses 1-14.

[0288] Clause 17. The method of any one of Clauses 15 or 16, wherein the carbon dioxide adsorbent molecule comprises:

[0289]

[0290] Its ions, or combinations thereof,

[0291] Where: each X + Independently classified as alkali metal cations, alkaline earth metal cations, transition metal cations, ammonium cations, alkylammonium cations, pyridine cations Cations, cationic species, or combinations thereof.

[0292] Clause 18. A method for forming carbon dioxide adsorbent molecules, the method comprising:

[0293] Hydroxymethylated melamine is formed by reacting a first mixture containing melamine and a formaldehyde source; and

[0294] A second mixture containing the hydroxymethylated melamine and an organic amine source is reacted to form a carbon dioxide adsorbent molecule, wherein the organic amine source is different from the melamine.

[0295] Clause 19. The method of Clause 18, wherein the carbon dioxide adsorbent molecule comprises any one of the carbon dioxide adsorbent molecules of Clauses 1-14.

[0296] Clause 20. The method of any one of Clauses 18 or 19, wherein the carbon dioxide adsorbent molecule comprises:

[0297]

[0298] Its ions, or combinations thereof.

[0299] Clause 21. A method for capturing carbon dioxide (CO2), comprising:

[0300] A gas stream or gas source containing CO2 is introduced together with a composition containing carbon dioxide adsorbent molecules, the carbon dioxide adsorbent molecules containing organic amine groups; and

[0301] A CO2-enriched composition is formed.

[0302] Clause 22. The method of Clause 21, wherein the CO2 enrichment composition comprises CO2 bound to the carbon dioxide adsorbent molecule.

[0303] Clause 23. The method of Clause 22, wherein the CO2 bound to the carbon dioxide adsorbent molecule is carbonate (CO3-). 2- ), bicarbonate (HCO3) - (or combinations thereof).

[0304] Clause 24. The method of any one of Clauses 22 or 23, wherein the CO2 bound to the carbon dioxide adsorbent molecule is in the form of a salt, the salt comprising: a cation comprising the carbon dioxide adsorbent molecule; and an anion comprising carbonate (CO3) ions. 2- ), bicarbonate (HCO3) - ), or combinations thereof.

[0305] Article 25. The method of any one of Articles 21-24, further comprising:

[0306] CO2 is removed from the CO2 enrichment composition by subjecting it to heat, acidic conditions, alkaline conditions, hydrolysis, electrolysis, electromagnetic radiation, ion exchange, increased pressure, vacuum pressure, or a combination thereof; and

[0307] Regenerate the carbon dioxide adsorbent molecules.

[0308] Clause 26. The method of Clause 25, wherein removing CO2 from the CO2 enrichment composition comprises subjecting the CO2 enrichment composition to heat, wherein subjecting the CO2 enrichment composition to heat the CO2 enrichment composition at a temperature of about 40°C to about 250°C.

[0309] Clause 27. The method of Clause 26, wherein the temperature is from about 40°C to about 160°C.

[0310] Article 28. The method of any one of Articles 25-27, wherein the removed CO2 is isolated for storage, converted into a chemical substance or feedstock, or a combination thereof.

[0311] Clause 29. A method for capturing carbon dioxide (CO2), comprising:

[0312] Contacting a gas stream or gas source containing CO2 with a composition containing carbon dioxide adsorbent molecules, the carbon dioxide adsorbent molecules containing organic amine groups; and

[0313] This causes the complex containing CO2 bound to the carbon dioxide adsorbent molecule to precipitate.

[0314] The method of Clause 30 and Clause 29, wherein the CO2 bound to the carbon dioxide adsorbent molecule is carbonate (CO3-). 2- ), bicarbonate (HCO3)- (or combinations thereof).

[0315] Clause 31. The method of any one of Clauses 29 or 30, wherein the CO2 bound to the carbon dioxide adsorbent molecule is in the form of a salt, the salt comprising:

[0316] A cation, the cation comprising the carbon dioxide adsorbent molecule; and

[0317] Anion, which contains carbonate (CO3) 2- ), bicarbonate (HCO3) - ), or combinations thereof.

[0318] Article 32. The methods of any one of Articles 29-31, further include:

[0319] CO2 is removed from the complex by subjecting it to heat, acidic conditions, alkaline conditions, hydrolysis, electrolysis, electromagnetic radiation, ion exchange, increased pressure, vacuum pressure, or a combination thereof; and

[0320] Regenerate the carbon dioxide adsorbent molecules.

[0321] Clause 33. The method of Clause 32, wherein removing CO2 from the complex includes subjecting the complex to heat, wherein subjecting the adsorbent-CO2 complex to heat the complex at a temperature of about 40°C to about 250°C.

[0322] Clause 34. The method of Clause 33, wherein the temperature is from about 40°C to about 160°C.

[0323] Article 35. The method of any one of Articles 29-34, wherein the removed CO2 is isolated for storage, converted into a chemical substance or feedstock, or a combination thereof.

[0324] Clause 36. A composition for absorbing or desorbing CO2, comprising: a carbon dioxide adsorbent molecule comprising a melamine-formaldehyde reaction product modified with an organic amine source, the organic amine source being different from melamine.

[0325] The composition of Clause 37. Clause 36, wherein the carbon dioxide adsorbent molecule further comprises an ionizable functional group, a polar non-ionizable functional group, or a combination thereof, which are combined with the melamine-formaldehyde reaction product, the ionizable functional group and the polar non-ionizable functional group being different from melamine and the organic amine source.

[0326] Clause 38. A composition of any one of Clauses 36 or 37, wherein the organic amine source comprises a primary amine, a secondary amine, a tertiary amine, an imine, a carbamate, a Schiff base, or a combination thereof.

[0327] Clause 39. The composition of any one of Clauses 36-38 further comprises a solvent.

[0328] Compositions of Clause 40 and Clause 39, wherein the solvent comprises water, an organic solvent, or a combination thereof.

[0329] The composition of Clause 41. Clause 40, wherein the organic solvent comprises an alcohol solvent.

[0330] Clause 42. The composition of any one of Clauses 36-41 further comprises an additive.

[0331] The composition of Clause 43. Clause 42, wherein the additive comprises a metal hydroxide.

[0332] Clause 44. A composition of any one of Clauses 36-43, wherein the carbon dioxide adsorbent molecule is represented by formula (IA):

[0333]

[0334] in:

[0335] A in formula (IA) 1 A 2 and A 3 Each of them is independently CH2 or CH2OCH2;

[0336] R of formula (IA) 1 and R 2 Each of the following is an organic amine, which comprises:

[0337]

[0338] or ,

[0339] The wavy key in equations (III-A) to (III-E) represents the key with A. 1 Or A 2 The connection; and

[0340] R of formula (IA) 3 It is an organic amine of formula (III-A) to (III-E), an ionizable functional group or a polar non-ionizable functional group.

[0341] The composition of Clause 45. Clause 44, wherein: when R of formula (IA) 3 When the functional group is ionizable, the ionizable functional group is selected from the group consisting of: sulfate, sulfonate, phosphate, phosphonate, carboxylic acid, and combinations thereof; when R of formula (IA) 3When the functional group is a polar, non-ionizable functional group, the polar, non-ionizable functional group is a hydroxyl group (-OH); or a combination thereof.

[0342] Clause 46. A composition of any one of Clauses 36-43, wherein the carbon dioxide adsorbent molecule comprises one or more of the following:

[0343]

[0344]

[0345]

[0346]

[0347] Where: each X in equations (VA) to (VD) + Independently classified as alkali metal cations, alkaline earth metal cations, transition metal cations, ammonium cations, alkylammonium cations, pyridine cations Cations, or combinations thereof.

[0348] Clause 47. A composition of any one of Clauses 36-43, wherein the carbon dioxide adsorbent molecule comprises one or more of the following:

[0349] or

[0350]

[0351] Among them: A 1 and A 2 Each of them is independently CH2 or CH2OCH2.

[0352] Clause 48. A composition for absorbing or desorbing CO2, the composition comprising: a carbon dioxide adsorbent molecule comprising a reaction product of glyoxal; and an organic amine source comprising a urea functional group.

[0353] The composition of Clause 49. Clause 48, wherein the organic amine source comprises amidourea.

[0354] Clause 50. A composition of any one of Clauses 48 or 49, wherein the carbon dioxide adsorbent molecule comprises one or more of the following:

[0355] or .

[0356] The composition of any one of the provisions of Clause 51. Clause 48-50 further comprises a solvent, an additive, or a combination thereof.

[0357] Clause 52. A method comprising:

[0358] Contact a stream of gas containing CO2 with a composition containing water, optional additives, and carbon dioxide adsorbent molecules represented by formula (IA):

[0359]

[0360] in:

[0361] A in formula (IA) 1 A 2 and A 3 Each of them is independently CH2 or CH2OCH2;

[0362] R of formula (IA) 1 and R 2 Each of the following is an organic amine, which comprises:

[0363]

[0364] or ,

[0365] The wavy key in equations (III-A) to (III-E) represents the key with A. 1 Or A 2 The connection; and

[0366] R of formula (IA) 3 It is an organic amine of formula (III-A) to (III-E), with an ionizable functional group or a polar, non-ionizable functional group; and

[0367] The adsorbent-CO2 complex containing CO2 bound to the carbon dioxide adsorbent molecule is precipitated.

[0368] Clause 53. The method of Clause 52 further includes:

[0369] CO2 is desorbed from the adsorbent-CO2 complex by subjecting it to heat, acidic conditions, alkaline conditions, hydrolysis, electrolysis, electromagnetic radiation, ion exchange, increased pressure, vacuum pressure, or a combination thereof; and

[0370] Regenerate the carbon dioxide adsorbent molecules.

[0371] Clause 54. The method of Clause 53, wherein desorbing CO2 from the adsorbent-CO2 complex comprises subjecting the adsorbent-CO2 complex to heat, wherein subjecting the adsorbent-CO2 complex to heat the adsorbent-CO2 complex at a temperature of about 40°C to about 250°C.

[0372] Clause 55. The method of Clause 54, wherein the adsorbent-CO2 complex is heated at a temperature of about 40°C to about 160°C.

[0373] Clause 56. The method of any one of Clauses 52-55, wherein an additive is present and it comprises a metal hydroxide.

[0374] Clause 57. A method comprising:

[0375] A stream of gas containing CO2 is contacted with a composition comprising water, optional additives, and carbon dioxide adsorbent molecules, the carbon dioxide adsorbent molecules comprising one or more of the following:

[0376] or ;and

[0377] The adsorbent-CO2 complex containing CO2 bound to the carbon dioxide adsorbent molecule is precipitated.

[0378] The methods of Clause 58 and Clause 57 further include:

[0379] CO2 is desorbed from the adsorbent-CO2 complex by subjecting it to heat, acidic conditions, alkaline conditions, hydrolysis, electrolysis, electromagnetic radiation, ion exchange, increased pressure, vacuum pressure, or a combination thereof; and

[0380] Regenerate the carbon dioxide adsorbent molecules.

[0381] Clause 59. The method of Clause 58, wherein desorbing CO2 from the adsorbent-CO2 complex includes subjecting the adsorbent-CO2 complex to heat, wherein subjecting the adsorbent-CO2 complex to heat at a temperature of about 40°C to about 250°C, for example about 40°C to about 160°C.

[0382] Article 60. A method of any of Articles 57-60, wherein an additive is present and it comprises a metal hydroxide.

[0383] As can be seen from the foregoing general description and specific aspects, while the forms of the described aspects have been illustrated and described, various modifications may be made without departing from the spirit and scope of this disclosure. Therefore, this disclosure is not intended to be limited thereto. Similarly, the term "comprising" is considered synonymous with the term "including." Likewise, whenever the transitional phrase "comprising" is used before a composition, element, or group of elements, it should be understood that we also consider it to be the same composition or group of elements for which the transitional phrases "consistently composed of," "composed of," "selected from," or "is" are used before stating the composition, element, or groups of elements, and vice versa; for example, the terms "comprising," "consistently composed of," or "composed of" also include the product of a combination of elements listed after the term.

[0384] For the purposes of this disclosure, and unless otherwise specified, all numerical values ​​in this detailed description and the claims herein are values ​​indicated by “about” or “approximately”, and take into account experimental errors and biases as would be expected by those skilled in the art. For the sake of brevity, only certain ranges are explicitly disclosed herein. However, any lower limit may be combined with any upper limit to describe a range not explicitly stated, and any lower limit may be combined with any other lower limit to describe a range not explicitly stated, and in the same manner, any upper limit may be combined with any other upper limit to describe a range not explicitly stated. For example, the description of the numerical range 1-5 includes subranges 1-4, 1.5-4.5, 1-2, and other ranges. As another example, the numerical range 1-5 such as 2-4 includes subranges 1-4 and 2-5, and other ranges. Furthermore, a range includes each point or individual value between its endpoints, even if not explicitly stated. For example, the description of the numerical range 1-5 includes the digits 1, 1.5, 2, 2.75, 3, 3.80, 4, 5, and other digits. Therefore, each point or individual value can be used as its own lower or upper bound in combination with any other point or individual value or any other lower or upper bound to record a range that is not explicitly stated.

[0385] As used herein, the indefinite articles “a” or “an” mean “at least one…” unless otherwise specified or the context clearly indicates otherwise. For example, an aspect containing “carbon dioxide adsorbent molecules” includes an aspect containing one, two or more carbon dioxide adsorbent molecules, unless otherwise specified or the context clearly indicates that it contains only one carbon dioxide adsorbent molecule.

[0386] Although the foregoing addresses aspects of this disclosure, other and further aspects of this disclosure may be devised without departing from its essential scope, which is defined by the appended claims.

Claims

1. A composition for absorbing or desorbing CO2, the composition comprising: A carbon dioxide adsorbent molecule comprising a melamine-formaldehyde reaction product modified with an organic amine source, which is different from melamine.

2. The composition of claim 1, wherein the carbon dioxide adsorbent molecule further comprises an ionizable functional group, a polar non-ionizable functional group, or a combination thereof, which are combined with the melamine-formaldehyde reaction product, the ionizable functional group and the polar non-ionizable functional group being different from melamine and the organic amine source.

3. The composition of any one of claims 1 or 2, wherein the organic amine source comprises a primary amine, a secondary amine, a tertiary amine, an imine, a carbamate, a Schiff base, or a combination thereof.

4. The composition of any one of claims 1-3, further comprising a solvent.

5. The composition of claim 4, wherein the solvent comprises water, an organic solvent, or a combination thereof.

6. The composition of claim 5, wherein the organic solvent comprises an alcohol solvent.

7. The composition of any one of claims 1-5, further comprising an additive.

8. The composition of claim 7, wherein the additive comprises a metal hydroxide.

9. The composition of any one of claims 1-8, wherein the carbon dioxide adsorbent molecule is represented by formula (IA): in: A in formula (IA) 1 A 2 and A 3 Each of them is independently CH2 or CH2OCH2; R of formula (IA) 1 and R 2 Each of the following is an organic amine, which comprises: or , The wavy key in equations (III-A) to (III-E) represents the key with A. 1 Or A 2 The connection; and R of formula (IA) 3 It is an organic amine of formula (III-A) to (III-E), an ionizable functional group or a polar non-ionizable functional group.

10. The composition of claim 9, wherein: When R of equation (IA) 3 When the functional group is ionizable, the ionizable functional group is selected from the group consisting of the following: sulfate, sulfonate, phosphate, phosphonate, carboxylic acid, and combinations thereof; When R of equation (IA) 3 When the functional group is a polar, non-ionizable functional group, then the polar, non-ionizable functional group is a hydroxyl group (-OH); or Its combination.

11. The composition of any one of claims 1-8, wherein the carbon dioxide adsorbent molecule comprises one or more of the following: in: Each X in equations (VA) to (VD) + It can be independently classified as an alkali metal cation, alkaline earth metal cation, transition metal cation, ammonium cation, alkylammonium cation, or pyridine cation. Cations, or combinations thereof.

12. The composition of any one of claims 1-8, wherein the carbon dioxide adsorbent molecule comprises one or more of the following: or in: A 1 and A 2 Each of them is independently CH2 or CH2OCH2.

13. A composition for absorbing or desorbing CO2, the composition comprising: A carbon dioxide adsorbent molecule, which comprises the reaction products of the following substances: Glyoxal; and Organic amine sources containing urea functional groups.

14. The composition of claim 13, wherein the organic amine source comprises amidourea.

15. The composition of any one of claims 13 or 14, wherein the carbon dioxide adsorbent molecule comprises one or more of the following: or .

16. The composition of any one of claims 13-15, further comprising a solvent, an additive, or a combination thereof.

17. A method comprising: Contact a stream of gas containing CO2 with a composition containing water, optional additives, and carbon dioxide adsorbent molecules represented by formula (IA): in: A in formula (IA) 1 A 2 and A 3 Each of them is independently CH2 or CH2OCH2; R of formula (IA) 1 and R 2 Each of the following is an organic amine, which comprises: or , The wavy key in equations (III-A) to (III-E) represents the key with A. 1 Or A 2 The connection; and R of formula (IA) 3 It is an organic amine of formula (III-A) to (III-E), with an ionizable functional group or a polar, non-ionizable functional group; and The adsorbent-CO2 complex containing CO2 bound to the carbon dioxide adsorbent molecule is precipitated.

18. The method of claim 17, further comprising: CO2 is desorbed from the adsorbent-CO2 complex by subjecting it to heat, acidic conditions, alkaline conditions, hydrolysis, electrolysis, electromagnetic radiation, ion exchange, increased pressure, vacuum pressure, or a combination thereof; and Regenerate the carbon dioxide adsorbent molecules.

19. The method of claim 18, wherein desorbing CO2 from the adsorbent-CO2 complex comprises subjecting the adsorbent-CO2 complex to heat, wherein subjecting the adsorbent-CO2 complex to heat the adsorbent-CO2 complex at a temperature of about 40°C to about 250°C.

20. The method of claim 19, wherein the adsorbent-CO2 complex is heated at a temperature of about 40°C to about 160°C.

21. The method of any one of claims 17-20, wherein an additive is present and the additive comprises a metal hydroxide.

22. A method comprising: A stream of gas containing CO2 is contacted with a composition comprising water, optional additives, and carbon dioxide adsorbent molecules, the carbon dioxide adsorbent molecules comprising one or more of the following: or ;and The adsorbent-CO2 complex containing CO2 bound to the carbon dioxide adsorbent molecule is precipitated.

23. The method of claim 22, further comprising: CO2 is desorbed from the adsorbent-CO2 complex by subjecting it to heat, acidic conditions, alkaline conditions, hydrolysis, electrolysis, electromagnetic radiation, ion exchange, increased pressure, vacuum pressure, or a combination thereof; and Regenerate the carbon dioxide adsorbent molecules.

24. The method of claim 23, wherein desorbing CO2 from the adsorbent-CO2 complex comprises subjecting the adsorbent-CO2 complex to heat, wherein subjecting the adsorbent-CO2 complex to heat the adsorbent-CO2 complex at a temperature of about 40°C to about 250°C.

25. The method of any one of claims 22-24, wherein an additive is present and the additive comprises a metal hydroxide.

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