Reinforced adsorbent fibers and uses

Abstract

The reinforced porous sorbent fibers include reinforcing yarns partially or completely embedded in a fibrous sorbent component that includes an active sorbent, such as a polyamine, inorganic particle sorbent, or amine-modified inorganic particle sorbent, dispersed in a porous polymer matrix. In certain examples, the yarn-reinforced sorbent fibers have attractive CO2 adsorption / desorption performance, good tensile mechanical strength, and / or flexibility.

Description

[Technical Field]

[0001] Related Applications This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 63 / 483,827, filed February 8, 2023, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Background of the Invention Carbon capture, utilization and storage (CCUS) generally refers to a range of technologies that are believed to play a key role in meeting global energy and climate goals. For example, these technologies are considered by many to be essential for keeping global temperature rise below 1.5 degrees Celsius (°C).

[0003] CCUS involves capturing CO2 from dilute gas streams such as flue gas, air, etc. In the case of flue gas, the CO2 concentration ranges from 8 to 14% by volume, while in the case of ambient air, the CO2 concentration is approximately 450 ppm. Currently, the upfront costs of capturing CO2 from various streams are over 80% of the total CCUS cost. In the case of direct air capture, the upfront costs for CO2 capture are nearly 99% of the total CCUS cost.

[0004] The primary method for CO2 capture involves aqueous amine-based solvent systems such as Econamine FG+, KS-1, Oase Blue, and Cansolv. However, these amine-based systems suffer from high energy losses from solvent regeneration (due to boiling and condensing 70% of the water). Another significant energy penalty is the energy consumed to pump large amounts of viscous solvent during solvent circulation. Furthermore, solvent-based systems suffer from water and solvent losses, requiring large amounts of water and solvent to be replenished. Furthermore, solvent loss itself contributes to global emissions and is a potential health hazard. A discussion of the drawbacks associated with these techniques can be found in review articles such as DJ Heldebrant, PK Koech, V. Glezakou, R. Rousseaau, D. Malhotra, and D.C. Cantu, "Water-lean solvents for post-combustion CO2 capture: fundamentals, uncertainties, opportunities, and outlook," Chem. Rev., 2017, 117, 9594; and S. Zeng, X. Zhang, L. Bai, X. Zhang, H. Wang, J. Wang, D. Bao, M. Li, X. Liu, and S. Zhang, "Ionic liquid based CO2 capture systems: structure, interaction and process," Chem. Rev., 2017, 117, 9625.

[0005] Solid adsorbents, such as metal organic frameworks (MOFs), diamine-appended MOFs, covalent organic frameworks (COFs), zeolites, porous silica, and porous polymer powders, have attracted significant attention because they can potentially achieve high adsorption efficiencies with much less energy consumption. Conventional solid adsorbents are typically synthesized in the form of crystalline powders with crystallite size scales ranging from nanometers to hundreds of microns.

[0006] However, powdered solid adsorbents such as MOFs are typically not readily available for industrial applications. Indeed, it has been reported that MOF powders can reduce pressure in pipelines, reducing flow or even completely blocking it. Their use can also lead to abrasion due to powder injection. Significant reductions in pure MOF components have also been reported for powder applications, along with other problems such as dust, clogging, and transportation and handling difficulties. See, for example, V. Ntouros, I. Kousis, A.L. Pisello, and M.N. Assimakopoulos, "Binding materials for MOF monolith shaping processes: A review towards real-life application," Energies, 2022, 15(4), 1489.

[0007] To overcome these problems, solid adsorbent powders can be formed into beads or pellets, typically 1 to 6 mm in diameter. However, adsorbent beds packed with beads or pellets typically suffer from low bed loading, high pressure drop, and attrition. Both pressure drop and mass transfer resistance are strongly influenced by the size of the adsorbent beads. Changing bead size has opposing effects on these two important factors. The interstitial space between beads in a fixed bed is proportional to the bead size. Because the resistance to fluid flow through the adsorbent is inversely proportional to the pore size of the packed bed, the use of small adsorbent beads results in high pressure drop. For this reason, commercially available adsorbent beads for fixed-bed operation generally have an average diameter greater than 2 mm. In addition, almost all of the surface area of ​​commercial adsorbents is located inside the adsorbent beads. For adsorption to occur, the adsorbate must be transported from the external fluid phase to the internal surface of the beads. The transport rate is influenced by two consecutive mass transfer mechanisms: (a) interfacial mass transfer, i.e., diffusion through the fluid boundary layer surrounding the outer surface of the adsorbent beads, and (b) intraparticle mass transfer, i.e., diffusion through the internal pore space (micropores and macropores) of the beads to the inner surface of the beads where adsorption occurs. The bead size has a significant effect on the rate of these two diffusion processes. Small beads provide a large fluid / solid contact area in the fixed bed for interfacial mass transfer and reduce the path length for intraparticle diffusion. Therefore, small adsorbent beads increase the adsorption rate and result in a narrow mass transfer zone for rapid and efficient operation of the adsorption / desorption cycle. Therefore, while small adsorbent beads are desirable for efficient adsorption processes, the minimum bead size is limited by the allowable hydrodynamic operating conditions of the fixed-bed adsorber, i.e., avoiding fluidization and excessive pressure drop.

[0008] Structured adsorbents such as monoliths and fibers offer improvements over traditional bead or pellet packed bed structures, as discussed, for example, in S. J. A. DeWitt, A. Sinha, J. Kalyanaraman, F. Zhang, M. J. Realff, and R. P. Lively, Critical comparison of structured contactors for adsorption-based gas separation, Annu. Rev. Chem. Biomol. Eng., 2018, 9, 129.

[0009] The review articles by F. Rezaei and P. Webley, entitled "Structuring adsorbents in gas separation processes," Sep. Purif. Techn., 2010, 70, 243, and F. Akhtar, L. Andersson, S. Ogunwumi, N. Hedin, and L. Bergstrom, entitled "Structuring adsorbents and catalysts by processing of porous powders," J. Eur. Ceram. Soc., 2014, 34, 1643, summarize the research efforts directed towards structured adsorbents.

[0010] Currently available adsorbent reactor configurations, such as fixed beds, moving beds, and fluidized beds, are summarized by C. Dhoke, A. Zaabout, S. Cloete, and S. Amin in the article “Review on reactor configurations for adsorption-based CO2 capture,” Ind. Eng. Chem. Res., 2021, 60, 3779 pages.

[0011] For carbon capture and storage (CCS), pressure swing packed bed adsorption or temperature swing packed bed adsorption using sorbent fibers offers several advantages compared to monoliths and conventional packed bed contactors. Generally, the pressure drop can be approximately 10-30 times lower than that of packed beds, even at high superficial velocities. Adsorbent fibers have a better mass / heat transfer coefficient than those of packed beds and monoliths. See "Microporous materials in scalable shapes: Fiber sorbents," by Y.H. Lee, J. Jeong, K. Kim, T. Hyun, A. Jamal, and D.Y. Koh, Chem. Mater., 2020, 32, 7081.

[0012] U.S. Patent Nos. 8,133,308, 8,257,474, and 8,377,172 disclose hollow fiber adsorbents formed from a dope containing a water-insoluble polymer and a specific inorganic adsorbent. However, these fibers lack the flexibility necessary for winding the fibers into structured devices. U.S. Patent No. 8,540,810 discloses an adsorption unit comprising an adsorbent hollow fiber having at least two layers: one layer of adsorbent particles embedded in a polymer matrix and one layer of polyaniline, which provides a means for heat transfer. These adsorbent fibers still suffer from poor flexibility, exhibiting bending angles of less than 30°.

[0013] Composite fibers comprising adsorbent particles (50% by weight, where weight % is abbreviated herein as "% w" or "%w") in a polymer matrix comprising a polymer or blend of polymers including at least one thermoplastic polymer are described in U.S. Pat. No. 10,525,399.

[0014] U.S. Patent No. 9,114,364 discloses hollow fibers for adsorption or filtration, the hollow fibers including a tubular matrix having a first end and a second end, and a wound channel formed through the tubular matrix and extending between the first and second ends. The disclosed adsorbent fibers have a curved configuration to facilitate mass transfer.

[0015] W. Quan, H.E. Holmes, F. Zhang, B.L. Hamlett, M.G. Finn, C.W. Abney, M.T. Kapelewski, S.C. Weston, R.P. Lively, and W.J. Koros, in Scalable formation of diamine-appended metal-organic framework hollow fiber sorbents for postcombustion CO2 capture, JACS Au, 2022, 2, 1350, describe an adsorbent hollow fiber comprising polyethersulfone and diamine-appended Mg-MOF.

[0016] U.S. Patent Application Publication No. 2023 / 0011904A1 discloses adsorbent fibers formed from a dope containing a water-insoluble polymer and a polyamine via a dry-jet wet-quench spinning process. U.S. Patent Application Publication No. 2023 / 0008877A1 discloses modular devices and systems including adsorbent fibers.

[0017] Braid reinforcement has been used to prepare tubular braided hollow fiber membranes, as described in U.S. Pat. Nos. 3,676,193, 4,061,821, 5,472,607, 6,354,444, 7,267,872, 7,306,105, 8,529,814, 8,827,085, 8,999,454, 9,643,129, 10,046,281, and 10,434,477. Generally, these braided-reinforced hollow fiber membranes address lateral mechanical strength, as discussed, for example, in A. Nazif, H. Karkhanechi, E. Saljoughi, S. Mousavi, and H. Matsuyama, "Effective parameters on fabrication and modification of braided hollow fiber membranes: a review," Membranes, 2021, 11, 884, and Z. Fan, C. Xiao, H. Liu, Q. Huang, and J. Zhao, "Structure design and performance study on braid-reinforced cellulose acetate hollow fiber membranes," J. Membrane Sci., 2015, 486, 248. Summary of the Invention [Problem to be solved by the invention]

[0018] While adsorbent-loaded fibers are known, fibers with high adsorbent loadings generally lack flexibility and axial mechanical strength (tensile strength). In addition, they tend to break during handling. Approaches to increasing the mechanical properties of porous adsorbent fibers rely on increasing the mass of the matrix polymer. However, this reduces the active adsorbent content in the adsorbent fiber, leading to additional energy consumption. Furthermore, increasing the matrix polymer content reduces the surface area for CO2 adsorption and increases gas diffusion resistance.

[0019] While preparing tubular braid-reinforced hollow fiber membranes has been reported, such an approach does not appear to have been attempted or even contemplated for fibrous adsorbents. Furthermore, the concern addressed by existing braid-reinforced hollow fiber membranes is transverse strength, not axial strength.

[0020] Therefore, there remains a need for additional purification methods and adsorbents suitable for removing or capturing acid gases, and a need for strong, flexible adsorbent fibers that can be scaled up to meet industrial requirements in a cost-effective manner. [Means for solving the problem]

[0021] The present invention relates generally to techniques for removing impurities (also referred to herein as "contaminants"), such as acid gases, from a contaminant-containing medium, such as a raw fluid stream.

[0022] In one of its aspects, the invention features a reinforced adsorbent fiber that includes a reinforcing thread partially or completely embedded in a porous solid adsorbent material, such as a fibrous adsorbent. "Fiber adsorbent" refers to a system that includes an active adsorbent, such as solid porous adsorbent particles or a polyamine, dispersed (e.g., homogeneously) in a matrix, which is often an open-pore matrix that can be made of a polymeric material.

[0023] In some embodiments, the reinforced adsorbent fibers described herein contain porous polymer fibers loaded with porous particles such as, for example, zeolites, MOFs, COFs, porous aromatic frameworks (PAFs), activated alumina, carbon, graphene, silica, or layered double hydroxides (LDHs).

[0024] In other embodiments, the reinforced adsorbent fibers comprise porous polymer fibers loaded with amine-attached porous particles, such as, for example, amine-modified zeolites, MOFs, COFs, PAFs, activated alumina, carbon, graphene, silica, or LDHs.

[0025] In a further embodiment, the adsorbent fiber component in the reinforced adsorbent fibers is a porous solid amine adsorbent that can be prepared by contacting a first (e.g., dope) solution comprising a water-insoluble polymer and a water-soluble amine polymer with an aqueous solution containing a multifunctional chemical agent. The first solution can be obtained by dissolving the water-insoluble polymer and the water-soluble amine polymer in a polar solvent.

[0026] The reinforcing yarns can be made from polymeric or natural fibers or yarns, from carbon, metal, or metal alloys. The yarns can add axial strength to the reinforced adsorbent fiber and can be braided or non-braided. Solid or hollow yarns can be used. In many cases, the reinforcing yarns can be distinguished in some way from the material that encases them. Their orientation can be parallel or nearly parallel (substantially parallel) to the length of the reinforced fiber. In the cross-section of the reinforcing fiber, the reinforcing yarns can be centrally located or off-center.

[0027] Reinforced adsorbent fibers can be produced by dry-wet solution spinning techniques, in which a dope solution is co-extruded with a reinforcing yarn. Specific approaches include the dry-jet wet-quench spinning process (non-solvent induced phase inversion) or temperature induced phase separation (TIPS). In an exemplary embodiment, a feed yarn (e.g., braided or non-braided) is fed through the center of a spinneret.

[0028] Reinforced adsorbent fibers may be hollow or solid (non-hollow). In many cases, they exhibit improved axial strength (compared to comparable adsorbent fibers that do not include reinforcing yarns). Flexibility, along with porosity (typically comprising open cells or interconnected pores), is yet another property that characterizes at least some of the reinforced adsorbent fibers described herein.

[0029] The reinforced sorbent fibers can be packaged into modular adsorption devices. An exemplary adsorption device (also referred to herein as a "cartridge") includes multiple (i.e., two or more) adsorbent fibers placed parallel to or wound, e.g., spirally, around a central tube. One or more cartridges can be assembled to form a module.

[0030] The reinforced adsorbent fibers, as well as cartridges and / or modules containing them, can be used to remove contaminants from fluid streams. In one example, a fluid stream is directed to a module containing at least one adsorbent device, the adsorbent device containing the reinforced adsorbent fibers. By contacting the fluid stream with the reinforced adsorbent fibers, at least a portion of the contaminants are adsorbed by the reinforced adsorbent fibers, producing a purified stream that can be collected from the module.

[0031] For many applications, the reinforced adsorbent fibers can be regenerated by desorbing the trapped impurities using, for example, heat, reduced pressure or vacuum, or a combination thereof.

[0032] The practice of embodiments of the present invention provides many advantages. For example, at least some of the reinforced adsorbent fibers described herein provide good fiber flexibility and / or improved axial mechanical strength. Due to these properties, the reinforced fibers can be incorporated into adsorption devices and / or modules.

[0033] In many cases, reinforced sorbent fibers can be used to remove contaminants, particularly acid gases such as CO, H, S, and SO, from flue gas, biogas, hydrogen gas, natural gas, air, or another fluid stream. Practicing the present invention can be very attractive when dealing with low-concentration separations and can provide high recovery rates, lower energy consumption, and / or better economics in applications such as direct air capture, CO removal for LNG production, and CO capture from flue gas. Employing carbon or metal reinforcing yarns can facilitate the contaminant desorption / fiber regeneration process.

[0034] The above and other features and advantages of the present invention, including various details of construction and combination of parts, will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular methods and apparatus embodying the invention are shown by way of illustration and not as limitations of the invention. The principles and features of this invention may be employed in various and numerous embodiments without departing from the scope of the invention. [Brief explanation of the drawings]

[0035] In the accompanying drawings, wherein reference characters refer to the same parts throughout the different views, the drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

[0036] [Figure 1] FIG. 1 shows a cross section of a possible yarn or braid.

[0037] [Figure 2] Figure 2 shows the setup for spinning reinforced adsorbent fibers by the dry jet wet quenching process.

[0038] [Figure 3] FIG. 3 is a photograph of a cross section of a reinforced adsorbent fiber containing PEI with embedded threads.

[0039] [Figure 4] FIG. 4 is a TGA graph showing the activation of a yarn-reinforced adsorbent fiber at 110 degrees Celsius (°C) and the adsorption of CO at 30°C. The yarn-reinforced adsorbent fiber was prepared by contacting a dope solution containing PAN and PEI with a 5% MgSO solution.

[0040] [Figure 5] FIG. 5 is a photograph of a cross section of a reinforced adsorbent fiber containing 75% w CALF-20 embedded in a porous PAN matrix.

[0041] [Figure 6] FIG. 6 is a photograph of reinforced adsorbent fibers containing 75% w CALF-20 spirally wound around a metal rod (3 / 8" (approximately 9.5 mm) OD).

[0042] [Figure 7] Figure 7 shows the adsorption profiles of pure CO2 for CALF-20 powder, 75%w CALF-20 / PAN fiber without yarn, and 75%w CALF-20 / PAN fiber reinforced with polyester yarn. DETAILED DESCRIPTION OF THE INVENTION

[0043] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0044] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, all conjunctions used should be understood in the most inclusive sense possible. Accordingly, the term "or" should be understood as having the definition of a logical "or" rather than a logical "exclusive-or" unless the context clearly requires otherwise. Furthermore, the singular forms and articles "a," "an," and "the" are intended to include the plural unless expressly stated otherwise. Furthermore, the terms "includes," "comprises," "including," and / or "comprising," as used herein, specify the presence of stated features, integers, steps, operations, elements, and / or components, but will be understood not to preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Furthermore, when an element, including a component or subsystem, is referred to and / or shown as being connected or coupled to another element, it will be understood that the element can be directly connected or coupled to the other element, or intervening elements may be present.

[0045] Terms such as "first" and "second" are used herein to describe various elements, but it should be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Thus, an element discussed below may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the teachings of the present invention.

[0046] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning consistent with the meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless expressly defined as such in this specification.

[0047] The present invention relates generally to reinforced adsorbent fibers and methods of making and using them. Reinforced adsorbent fibers include reinforcing yarns partially or completely embedded in a solid adsorbent material, which in many embodiments is porous. As used herein, the term "fibrous adsorbent" or "adsorbent fiber" refers to a system in which a porous adsorbent material or polyamine, typically in particulate form, is dispersed, e.g., homogeneously, throughout a matrix, e.g., an open-pore matrix, often a polymeric open-pore matrix. Adsorbent fibers can be produced via conventional dry-jet wet-quench spinning techniques and can be manufactured in a variety of configurations, such as monolithic (solid or solid), hollow, bilayer, and inverse fiber, to name a few, depending on the dope composition and spinning parameters.

[0048] Reinforced adsorbent fibers, also referred to herein as "yarn-reinforced adsorbent fibers," include reinforcing yarns that are partially or completely embedded (buried or wrapped) within the fibrous adsorbent component of the reinforcing fibers.

[0049] The reinforcing yarns are embedded longitudinally in an orientation that may be parallel or nearly parallel to the reinforcing fiber itself. In a cross-sectional view of the reinforced adsorbent fiber, the reinforcing yarns may be off-center or centrally positioned. In some embodiments, this placement remains uniform throughout the entire length of the reinforced adsorbent fiber. In other embodiments, this placement varies along the length of the reinforced adsorbent fiber. For example, the reinforcing yarns may be centrally positioned over some segments and somewhat (slightly or more than slightly) off-center over other segments. In a partially embedded configuration, the outer surfaces of the reinforcing yarns form the outer surface of the reinforced adsorbent fiber.

[0050] The reinforcing yarns that can be used are in the form of monofilaments, multifilaments, or a mixture of both. Some embodiments utilize a single yarn. Other embodiments utilize multiple (two or more) yarns, which can be aligned or braided together.

[0051] The cross section of the reinforcing yarns may be solid or hollow. In one example, hollow adsorbent fibers are produced using hollow tubular braiding. This type of reinforcing yarn can be obtained from a braiding machine or prepared as described in U.S. Patent Nos. 8,827,085 and 10,906,006.

[0052] Any suitable cross-sectional shape can be used. Examples include, but are not limited to, circular, oval, star-shaped, or other regular or irregular shapes. Some possible options are illustrated in FIG. 1.

[0053] The reinforcing yarns can have a diameter sized according to the desired thickness of the reinforced adsorbent fibers. In one example, the reinforcing yarns have a thickness in the range of about 0.1 mm to about 2 mm.

[0054] The reinforcing yarns can be made from natural (cotton, silk, wool, etc.), polymer (polyethylene, polypropylene, polyester, nylon, polyacrylonitrile, cellulose acetate, polyvinylidene fluoride (PVDF), polyimide, polysulfone, polyphenylene oxide, polyaramid, etc.) fibers or yarns, metal (copper, aluminum, etc.), metal alloys such as steel or bimetals (nichrome, etc.), glass fibers, or carbon (e.g., from carbon fiber). When polymeric yarns are utilized, the reinforcing yarns can be made from homopolymers, copolymers, polymer blends, etc. Suitable yarns can be commercially available (e.g., from Toray Industries, Inc., Indorama Corporation Pte Ltd, Weiqiao Textile Company Limited, Far Eastern New Century, and Unifi Inc.) or can be custom-made. For example, braided thread can be prepared using a braiding machine in a process such as that described in US Pat. No. 9,643,129.

[0055] Some applications utilize reinforcing yarns that have the same chemical composition as the polymer utilized to manufacture the porous adsorbent fiber component, e.g., the polymer used to form the open-pore polymer matrix in the adsorbent fiber. Utilizing the same chemical composition for the reinforcing yarns and the adsorbent matrix is ​​believed to enhance adhesion between the yarns and the fibrous adsorbent in which they are partially or completely embedded.

[0056] In one embodiment, the reinforcing yarns are made from a metal or metal alloy, such as steel, aluminum, copper, nichrome, etc. In another embodiment, the reinforcing yarns are made from fiberglass or carbon fiber.

[0057] When metal or carbon reinforcement yarns are utilized, the yarns can serve one or more functions. For example, the metal or carbon reinforcement yarns can provide axial mechanical strength to the reinforcement fiber and / or can transmit electrical current and thus provide heat through the yarn during the fiber regeneration operation. In some embodiments, electricity is derived from renewable sources such as solar or wind power.

[0058] Selection of appropriate reinforcing yarns can take into account factors such as mechanical strength, compatibility between the yarns and the fibrous adsorbent components in the reinforcing fiber (to reduce or minimize the occurrence of delamination), maximum regeneration temperature, etc. In particular examples, the yarns are monofilaments made from polyethylene terephthalate (PET), polyacrylonitrile (PAN), polyimide, polyamide, cotton, steel, copper, aluminum, nichrome, carbon, or any combination thereof.

[0059] In many embodiments, the fibrous adsorbent component that partially or completely encases the reinforcing yarns contains active adsorbent material in the form of solid adsorbent particles.

[0060] Adsorbent particulates that can be used include, for example, those known in adsorbent-based fluid separation, particularly gas separation, with non-limiting choices including zeolites, MOFs, COFs, PAFs, activated alumina, carbon, graphene, silica, layered double hydroxides (LDHs), and the like.

[0061] MOF particle materials are independently CALF-20, CALF-15, UIO-66, UIO-66-NH2, UIO-67, UIO-68, IISERP-MOF-2, MIL-53, MIL-88, MIL-96, MIL-101, MIL-140L, MIL-16 0, MUF-15, MUF-16, ZIF-7, ZiF-8, ZIF-9, ZIF-10, ZIF-12, ZIF-68, ZIF-69, ZIF-70, ZIF-78, ZIF-79, ZIF-81, ZIF-82, ZIF-90, MOF-2, MOF-3, MO The MOF may be a single MOF or a mixture of MOFs selected from the group consisting of MOF-4, MOF-5, MOF-70, MOF-73, MOF-74, MOF-75, MOF-76, MOF-177, MOF-303, MOF-505, MOF-80, MOF-808, CAU-10, CAU-10-H, Al(OH) fumarate, Al-formate, Mg-formate, Zr-fumarate, HKUST-1, Fe-BTC, PCN-224, PCN-250, UTSA-16, MIL-120(Al), and Mg(Hgal).

[0062] In some embodiments, the adsorbent is functionalized (modified) with a suitable functional group, often an amine-containing functional group. For example, amine-functionalized magnesium MOFs are disclosed in U.S. Pat. Nos. 9,861,953 and 10,137,430 (entitled "Alkylamine Functionalized Metal-Organic Frameworks for Composite Gas Separations"). These documents describe functionalized metal-organic framework adsorbents with ligands containing basic nitrogen groups, such as alkylamines and alkyldiamines, appended to the metal center.

[0063] In particular examples, the active adsorbent is a zinc MOF such as CALF-20, as disclosed in U.S. Pat. No. 11,230,562 (entitled "Synthesis of zinc MOF materials"), a zeolitic imidazolate framework, such as ZIF-94 (described, for example, in the article by Q. Wang et al. entitled "CO2 capture from high humidity flue gas using a stable metal-organic framework," Molecules, 2022, 27, 5608), or an amine-appended magnesium MOF, such as epn-grafted Mg2(dobpdc) (epn=1-ethylpropane-1,3-diamine), as disclosed, for example, in U.S. Pat. Nos. 9,861,953 and 10,137,430.

[0064] The solid sorbent particles can have a particle size of 100 μm or less, typically 10 μm or less, and in some cases even 1 μm or less. The amount of solid particles in the sorbent fibers may vary from 25 to 90% by weight (expressed as % w), typically from 30% w to 80% w. In illustrative examples, the solid particles are present in the fibers in an amount ranging from about 30 to about 40, 50, 60, or 70 w%, from about 40 to about 50, 60, 70, or 80 w%, from about 50 to about 60, 70, or 80 w%, from about 60 to about 70 or 80 w%, or from about 70 to about 80 w%.

[0065] One embodiment of the present invention relates to reinforced sorbent fibers in which the active adsorbent is an amine-containing compound (a material containing functional groups such as -NH, -RNH, or -RR'N), such as a water-soluble amine-containing polymer. As used herein, the term "amine-containing polymer" or "amine polymer" refers to a polymer containing -NH, -RNH, or -RR'N functional groups bonded to or separated by -CHCH-, -CHCHCH-, or -CHCHCHCHCH-. The R and R' groups may be methyl, ethyl, propyl, etc., and may be the same or different.

[0066] Water-soluble amine polymers can be provided in a wide range of molecular weights, for example, from about 400 to about 10,000,000. Some embodiments utilize water-soluble amine polymers in the range of from about 1,000 to about 1,000,000.

[0067] For example, as described in U.S. Patent Application No. 17 / 859,139 (published as U.S. Patent Application Publication No. 2023 / 0011904A1 on January 12, 2023) and International Application No. PCT / US22 / 36293 (published as WO 2023 / 287632A1 on January 19, 2023), both entitled "Porous Solid Amine Adsorbents and Applications" and both filed July 7, 2022 (the entire contents of which are incorporated herein by reference), a water-soluble amine polymer can be provided, along with other components, in a first solution (mixture or blend), also referred to herein as a "dope" solution or simply a "dope." In the context of hollow fiber manufacturing, a "dope" is a blend of polymer, solvent, and optionally other components that is passed through the annular space of a spinneret to form a nascent hollow fiber.

[0068] In one embodiment, the water-soluble amine compound (eg, polymer) includes a unit skeleton structure represented by the following formula 1:

[0069] -[(CH2) x -NR] y - (1)

[0070] In the above unit skeleton structure, R may be hydrogen or a branched chain, x is an integer of 1 to 4, and y is an integer of 2 to 1,000,000. In certain embodiments, the amine compound is a linear or branched polyethyleneimine (when x=2) or a linear or branched polypropyleneimine (when x=3).

[0071] In another embodiment, the water-soluble amine compound (eg, polymer) comprises a structure represented by Formula 2:

[0072] -[(CH2) x -CH(NH)] y - (2)

[0073] wherein x is an integer from 1 to 4, and y is an integer from 2 to 1,000,000. In certain embodiments, the amine compound represented by Formula 2 is polyvinylamine (when x=1).

[0074] Water-soluble amine polymers can be partially crosslinked by reacting them with a crosslinking agent to increase their molecular weight. Partial crosslinking can, in some cases, be beneficial in increasing the (dope) solution viscosity and the final adsorbent adsorption capacity. The degree of partial crosslinking is controlled below the gel point of the solution and is often achieved by adding a controlled amount of crosslinking agent to the solution. Suitable crosslinking agents include glyoxal, glutaraldehyde, bisphenol A diepoxy, isocyanates, metal cations, and the like. In one exemplary embodiment, the crosslinking agent is bisphenol A diepoxy.

[0075] The amount of the water-soluble amine compound can be within the range of about 5 to about 50% based on the total weight of the first (eg, dope) solution.

[0076] Also present in the dope solution are water-insoluble matrix polymers. These polymers can be natural or synthetic. Examples of natural polymers include lignin, cellulose, and cellulose derivatives (e.g., cellulose acetate). Examples of synthetic polymers include polyacrylonitrile, poly(methyl methacrylate), polystyrene, poly(ethylene terephthalate), aromatic polyamides, aliphatic polyamides, polyimides, polyesters, polyetherketones, polysulfones, polyethersulfones, polyetheresters, polysulfones, polyvinyl fluoride, polyvinyl difluoride, polyvinyl chloride, polyvinyl butyral, polybenzimidazole, polybenzoxazole, polyazoaromatics, poly(2,6-dimethylphenylene oxide), polyphenylene oxide, polyureas, polyurethanes, polyhydrazides, polyazomethines, polyacetals, polyquinoxalines, polyamide esters, polyacetylenes, polymers with intrinsic porosities (PIMs), polyesters, and any combinations (blends) or copolymers thereof.

[0077] Solvents used to make the dope solution can include non-polar solvents, polar protic solvents, and polar aprotic solvents, such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and dimethyl sulfoxide (DMSO), and combinations thereof.

[0078] The solvent may also include a non-solvent. The non-solvent component can be liquid or solid and can be selected to serve any number of functions: viscosity adjustment, imparting porosity and / or other properties to the adsorbent product, or other purposes. Examples of non-solvents that can be used include, but are not limited to, water, aliphatic alcohols, particularly polyhydric alcohols such as ethylene glycol, glycerin, polyethylene oxide and polypropylene oxide, polyvinyl alcohol, polyvinylpyrrolidone, surfactants such as alkylaryl polyether alcohols, alkyl sulfates, alkylaryl sulfates, triethyl phosphate, formamide, and salts such as lithium chloride. Combinations of non-solvents can also be used. The nature and amount of the non-solvent may depend on the desired product properties, process and / or equipment parameters, or other factors. Generally, the amount of non-solvent may be in the range of about 0% to about 30% by weight of the dope solution.

[0079] As described in U.S. Patent Application No. 17 / 859,139 (published as U.S. Patent Application Publication No. 2023 / 0011904) and International Application No. PCT / US22 / 36293 (published as WO 2023 / 287632), porous solid adsorbents can be prepared by contacting a first solution (such as the dope solution described above) with a second solution. In one example, the second solution is an aqueous solution containing a polyvalent (multifunctional) acid, i.e., an acid having two or more acid functional groups. In another example, the second solution is an aqueous solution containing Ca 2+ , Cu 2+ , Zn 2+ , and Mg 2+ It is an aqueous solution containing polyvalent metal ions such as:

[0080] The aqueous solution may contain water in an amount of at least 80% by weight, preferably 95% by weight or more, based on the total weight of the aqueous solution.

[0081] The polyfunctional acid may be an inorganic acid, such as sulfuric acid or phosphoric acid, or an organic acid. Examples of suitable polyfunctional organic acids (having two or more -COOH groups) include oxalic acid, citric acid, malic acid, tartaric acid, humic acid, dithiodipropionic acid, succinic acid, sulfosuccinic acid, phytic acid, trans-aconitic acid, polyacrylic acid and copolymers thereof, polyvinylphosphonic acid and copolymers thereof, polystyrene sulfonic acid and copolymers thereof, polystyrene phosphonic acid and copolymers thereof, polystyrene carboxylic acid and copolymers thereof, etc., or a mixture of any of these.

[0082] In one example, the acid concentration in the aqueous solution is in the range of 0.01% to 30%, preferably 0.1% to 10%, based on the total weight of the aqueous solution.

[0083] In some cases, the second solution is simply an aqueous acid solution. In other embodiments, the second solution further comprises one or more additives.

[0084] The second solution containing metal ions typically employs metal ions capable of forming multi-ligand metal complexes. The metal ions may be components in multifunctional metal salts.

[0085] Examples of polyfunctional metal ions that can be used include Cu + , Cu 2+ , Ca 2+ , Ni 2+ , Zn 2+ , Pd 2+ , Mg 2+ , Co 2+ , Cr 2+ , Fe 2+ , Fe 3+ The selection of the metal ion concentration depends on the nature of the metal ion, the residence time of the first solution (e.g., dope) in the metal ion solution, the solution temperature, the desired metal concentration in the final adsorbent, or other factors. The use of metal ions can be advantageous due to their low cost and, in some cases, synergistic CO adsorption effect.

[0086] In some embodiments, the concentration of metal ions in the solution is in the range of 0.001M to 5M, preferably in the range of 0.01M to 2M.

[0087] Without wishing to be bound by any particular theory or explanation, it is believed that when the first solution (e.g., dope) is contacted with an aqueous solution containing a "multifunctional chemical agent" (e.g., a multifunctional acid or metal salt), the water-insoluble polymer chains are frozen into a solid state by non-solvent-induced phase inversion, while the water-soluble amine compound is frozen into a solid state by a rapid cross-linking reaction between at least some of the amine functional groups and the multifunctional chemical agent. It is further believed that without the multifunctional chemical agent, the water-soluble amine compound would rapidly diffuse into the aqueous solvent, preventing the formation of a functional adsorbent.

[0088] Reinforced adsorbent fibers can be manufactured using a variety of techniques.

[0089] The dry-jet wet-quench spinning process (non-solvent induced phase separation, or NIPS) involves feeding a reinforcing yarn (e.g., unbraided or braided) through the center of an extrusion die or spinneret, for example. The polymer may first be dissolved in a solvent, and then an active adsorbent, e.g., in powder form having a particle size of 100 μm or less, may be added along with optional additives such as CaCl, LiCl, polyethylene oxide, etc. The dope solution may be degassed under heat and / or vacuum before being extruded through the die or spinneret.

[0090] Reinforced adsorbent fibers can also be produced via the temperature-induced phase separation (TIPS) process by feeding reinforcing fibers (e.g., unbraided or braided) through the center of an extrusion die or spinneret. A blend of polymer and adsorbent particles is heated above the melting temperature of the polymer and subsequently extruded, during which the adsorbent and molten polymer pass through the extrusion die or spinneret.

[0091] The nascent fibers emerging from the die or spinneret can be passed through (or across) a cooling medium such as water / air so that the nascent fibers solidify.

[0092] For active adsorbents not provided as solid particles, reinforced adsorbent fibers can be produced using wet-dry solution spinning techniques, in which a dope solution (e.g., containing a water-insoluble polymer and an active adsorbent, such as a water-soluble amine-containing polymer) is fed through an annular region of a spinneret and is typically co-extruded with a reinforcing yarn fed through the center of the spinneret. In one example, the reinforcing yarn is a hollow tubular braid. The nascent fiber exiting the spinneret passes through an air gap and can then enter a coagulation medium (bath) where the fibrous adsorbent components coagulate. The coagulation medium can include a non-solvent or poor solvent for the polymer, while also being a good solvent for the solvent in the dope solution. To prepare reinforced adsorbent fibers containing porous solid amine adsorbents, the coagulation medium can include a multifunctional agent, such as a multivalent metal ion.

[0093] From the coagulation bath, the coagulated reinforced adsorbent fibers may be further processed by one or more operations such as washing, heat treating, and drying, to name a few. The coagulated fibers may be drawn from the coagulation bath onto and around a rotating barrel and then directed into a washing medium. Pulling and piddling into a washing barrel (such as the technique described in U.S. Pat. No. 8,753,741) may also be used.

[0094] For reinforcement fibers utilizing braided yarns, the fiber manufacturing process can include steps including preparing the braided yarns using, for example, a braiding machine in a process such as that described in U.S. Pat. No. 9,643,129.

[0095] An exemplary reinforcement fiber spinning process and system is shown in Figure 2. The process shown in this figure proceeds in the direction of the arrows and generally involves several steps performed in various components of the apparatus 10. Initially, a dope solution 12 and a reinforcement yarn 14 (the latter guided by elements 16a, 16b, which may be rollers or tension control devices) are fed to a spinneret 18 for co-extrusion. In one example, the dope solution 12 is fed (e.g., by pumping) from a reservoir 20, while the reinforcement yarn 14 is unwound from a suitable winding device 22.

[0096] To prepare reinforced hollow adsorbent fibers, the spinneret can have a tube-in-tube configuration, with the dope solution fed into the annular space between the inner and outer tubes. The yarn 14 can be a solid or hollow braid fed into the center of the spinneret. A bore fluid can be used, but is not required.

[0097] Obtaining reinforced hollow adsorbent fibers of the desired morphology or properties may depend on factors such as spinneret design, dope and bore fluid flow rates and / or physical properties, gap size, bath conditions, shear forces within the spinneret, ratio of dope to bore fluid volumetric flow rates, draw ratio, etc. U.S. Patent No. 5,181,940, the entire contents of which are incorporated herein by reference, provides details regarding the manufacture of hollow fiber membranes that may prove applicable.

[0098] Solid (non-hollow) reinforced adsorbent fibers can also be prepared by feeding the dope and reinforcing yarn through a needle array.

[0099] The nascent fibers 24 emerge from the spinneret, traverse the air gap, and are immersed in a coagulation bath 28. Using guide elements 30 (e.g., rollers or tension control devices), the resulting reinforced fibers 32 are drawn out of the coagulation bath and guided by a rotating device 34 (or another suitable device) into a washing bath 36, where the solvent is removed as completely as possible using a suitable solvent, such as water or alcohol. The reinforced yarn 38 can be recovered from the washing bath for use or further processing.

[0100] Drying can be carried out, for example, under ambient conditions or by applying heat, for example, in an oven at a temperature such as 50°C to 150°C.

[0101] In some cases, a heat treatment (in a suitable oven or in a suitable fluid, e.g., a water bath) can be performed, for example, to impart desired mechanical properties to the product reinforced adsorbent fiber. In some cases, stepwise heating followed by a plateau temperature hold can be employed, optionally with one or more intervening cooling and reheating periods. The temperature is typically above room temperature and often at least 10°C below the glass transition temperature of the water-insoluble polymer. In an illustrative example, reinforced fibers containing a PEI-based porous solid amine adsorbent are heated and held at 100°C for 24 hours, for example, and then cooled to room temperature over 4 hours.

[0102] The apparatus 10 can include an optional braiding station 40 in an approach that provides an integrated system for producing braided yarns, for example, hollow tubular braid-reinforced adsorbent fibers.

[0103] The total mass of reinforcing yarn in the final dry adsorbent fiber is typically less than 30 wt%, preferably less than 20 wt%, and more preferably less than 10 wt%. In many embodiments, the reinforcing yarn is present in the final adsorbent fiber product in a range (by weight, expressed as "% w"), from about 2% w to about 20% w, e.g., from about 2% w to about 10% w. In particular examples, the amount of reinforcing yarn is from about 2% w to about 3, 4, 5, 6, 7, 8, or 9% w, from about 3% w to about 4, 5, 6, 7, 8, 9, or 10% w, from about 4% w to about 5, 6, 7, 8, 9, or 10% w, from about 5% w to about 6, 7, 8, 9, or 10% w, from about 6% w to about 7, 8, 9, or 10% w, from about 7% w to about 8, 9, or 10% w, from about 8% w to about 9 or 10% w, or from about 9% w to about 0% w. Other values ​​may be used, for example as determined by routine experimentation.

[0104] Reinforced hollow adsorbent fibers can be prepared with any desired inner and / or outer diameter. In one example, the reinforced adsorbent fibers have a thickness (outer diameter) in the range of about 0.1 mm to about 6 mm. The inner diameter can be in the range of about 0.05 mm to about 3 mm.

[0105] The product reinforced adsorbent fibers described herein have a density of about 0.2 g / cm 3 ~Approx. 1g / cm 3 , preferably about 0.3 g / cm 3 ~about 0.8g / cm 3 The density may be in the range of

[0106] Many of the properties that characterize the product reinforced adsorbent fibers can be obtained by selecting or adjusting equipment design, process conditions, or other factors. Porosity attributes can be tailored, for example, by solvent concentration, non-solvent, other additives, and crosslinker concentrations, or by other techniques.

[0107] After solidification, many of the product-reinforced adsorbent fibers can best be described as having an open-cell or interconnected structure. Specifically, the polymer matrix encapsulates the active adsorbent in an open-cell configuration without blocking (occluding) it, thus facilitating good mass transport.

[0108] The total porosity can be in the range of about 20% to about 80% by volume, preferably about 30% to about 70% by volume. In specific examples, the total porosity is in the range of about 30 to about 40, 50, or 60% by volume, about 40 to about 50, 60, or 70% by volume, about 50 to about 60 or 70% by volume, or about 60 to about 70% by volume.

[0109] The pore size of the polymer matrix can vary, and the adsorbents described herein can comprise macroporosity, microporosity, and / or nanoporosity. An ideal polymer matrix contains interconnected pores, and the active adsorbent is encapsulated within the matrix. The matrix does not contribute to transport resistance of the contaminant being removed. The types of matrix porosity most relevant for the removal of acid gases, such as carbon dioxide, from flue streams are macroporosity and / or microporosity. Surface porosity can be within exemplary ranges of 1 area% to 60 area%, e.g., about 10 area% to about 20 area%, 30 area%, 40 area%, 50 area%, or 60 area%, about 20 area% to about 30 area%, 40 area%, 50 area%, or 60 area%, about 30 area% to about 40 area%, 50 area%, or 60 area%, about 40 area% to about 50 area%, or 60 area%, and about 50 area% to about 60 area%.

[0110] The reinforced porous adsorbent fibers can be characterized by analytical techniques such as nitrogen BET (Brunauer-Emmett-Teller), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), or others now known in the art or developed in the future. Standard methods or protocols (e.g., thermogravimetric analysis, adsorption columns) can be used to evaluate the properties of the reinforced adsorbent fibers.

[0111] Advantageously, the methods described herein can produce reinforced adsorbent fibers that are self-supporting (also called "freestanding"), a property that describes a material or article that does not require an external support structure to prevent the material or article from collapsing or collapsing.

[0112] A major concern in hollow fiber membrane technology is lateral mechanical strength. This is because the productivity and separation efficiency of hollow fiber membranes depend on the pressure difference between the external pressure and the bore-side pressure (the lateral pressure differential). Because a lateral pressure differential can cause hollow fiber membranes to collapse, a goal of existing reinforced hollow fiber membranes is to maintain the lateral mechanical strength of the hollow fiber wall. However, with adsorbent fibers, there is no such pressure differential between the outer (shell) side of the fiber and its inner (bore) side. As a result, lateral mechanical strength is of little or no concern for the adsorbent fibers described herein.

[0113] However, a highly desirable property is axial (tensile) strength. In many embodiments, the reinforced adsorbent fibers have an axial strength greater than the axial strength of a comparable adsorbent fiber made from the same adsorbent material but without reinforcing yarns. The axial strength (tensile strength) of an adsorbent fiber can be determined using standard tensile strength measuring equipment, such as those manufactured by Instron. Exemplary reinforced adsorbent fibers have a tensile strength of at least about 2 MPa.

[0114] Additionally or alternatively, another property of great interest in the present invention is the flexibility of the reinforced adsorbent fibers. Empirically, this property can be measured by bending the fiber. A fiber can be said to be flexible if it can form a closed loop. The more flexible the fiber, the smaller the loop it can form. Reinforced adsorbent fibers that are flexible enough to be wrapped around a core member to form an adsorbent device (described further below) are particularly useful. In one example, the reinforced adsorbent fibers can be wrapped around a core member having a diameter of 1 cm or less to prepare a spirally wound adsorbent cartridge.

[0115] For many applications, the reinforced sorbent fibers described herein are packaged into modular adsorption devices. An exemplary adsorption device (also referred to herein as a "cartridge") includes multiple (i.e., two or more) adsorbent fibers placed parallel to or wound, for example, helically around a central tube. One or more cartridges can be assembled into a module. In an exemplary embodiment, a module for purifying a raw fluid (e.g., an acid gas) includes at least two adsorbents installed in a vessel in series or parallel. Operation can be in an axial or cross-flow configuration. Either shell-side or bore-side feed can be employed. In some embodiments, the module includes one or more heating elements that can be used to release adsorbed contaminants and regenerate the reinforced sorbent fibers. Various cartridge and / or module configurations that can be employed are described, for example, in U.S. Non-Provisional Patent Application No. 17 / 859,121 (published January 12, 2023 as U.S. Patent Application Publication No. 2023 / 0008877A1), both entitled "Modular Adsorbent Devices and Applications," and International Patent Application No. PCT / US22 / 36288 (published January 19, 2023 as WO 2023 / 287630A1), both of which are incorporated herein by reference in their entireties.

[0116] The reinforced sorbent fibers described herein, assembled into cartridges and / or modules, can be used, for example, to remove acid gases from a fluid stream, such as a flue gas stream. For example, a fluid stream containing an acid gas (e.g., CO) is contacted with the reinforced sorbent fibers. When at least a portion of the acid gas (e.g., CO) is adsorbed by the porous solid sorbent, the fluid stream becomes depleted in acid gas (e.g., CO), producing a stream purified with respect to the acid gas.

[0117] Reinforced adsorbent fibers containing contaminants such as acid gases (e.g., CO) can be regenerated for reuse or environmentally safe disposal. Various methods can be employed, using heat, vacuum, low pressure, or any combination of these. When the regeneration technique relies on heat, the desorption process can be a temperature swing adsorption (TSA) method, although many processes based on reduced pressure are known as pressure swing adsorption (PSA). Another useful technique that can be used to release adsorbed species from reinforced adsorbent fibers involves both heat and vacuum, a process known as temperature-vacuum swing adsorption (TVSA). These techniques are well known in the art (see, e.g., U.S. Pat. Nos. 9,457,340 and 8,974,577, the entire contents of both of which are incorporated herein by reference).

[0118] For reinforced adsorbent fibers using carbon or metal reinforcing yarns, regeneration can be achieved by supplying electricity to the yarns, thus heating them and desorbing the trapped contaminants. Energy can be supplied from conventional energy sources or can be derived from renewable (wind, solar) energy sources.

[0119] In terms of performance, the reinforced sorbent fibers described herein can have good CO2 adsorption / desorption characteristics. CO2 uptake from pure CO2 streams can be 0.03 g / g fiber to 0.30 g / g fiber. Adsorption can occur rapidly, for example, within a time frame ranging from about 1 minute to about 10 minutes. In purifying streams containing dilute CO2 amounts (e.g., 1% by volume or less), the reinforced sorbent fibers can produce purified streams with CO2 levels reduced by 80% or more. Desorption can be completed rapidly, often within a period of 1 to 10 minutes.

[0120] Reinforced sorbent fibers as described herein can also find application in the direct removal of acid gases from ambient air. Some approaches that can be employed to capture CO2 from the atmosphere typically rely on a blower to circulate air through a device containing the reinforced sorbent fibers. Once the CO2 is adsorbed, clean air is released. Once the reinforced sorbent fibers are saturated with CO2, the air circulation can be directed to another adsorption device, and the current adsorbent (sorbent) is regenerated by heat, vacuum, or a combination of both. The heat source can be derived from a renewable energy source, such as solar or wind energy.

[0121] Carbon dioxide released from the enhanced sorbent fibers described herein can be utilized to enhance oil recovery, to prepare synthetic fuels such as methanol, methane, jet fuel, etc. In some embodiments, the carbon dioxide is injected for permanent storage.

[0122] The present invention is further illustrated by the following non-limiting examples. [Example]

[0123] Example 1 A dope solution was prepared by dissolving 10.0 g of polyacrylonitrile and 10.0 g of polyethyleneimine (having a MW of 25,000) in 45.0 g of NMP. After degassing, the dope solution was transferred to a homemade fiber-spinning apparatus equipped with a spinneret and a polyester yarn feeder. The specific reinforcement yarn used was a black TEX21 spun polyester yarn with a diameter of approximately 0.005 in. (approximately 0.013 cm). The dope solution and yarn were extruded through the spinneret to form a nascent fiber, which was then fed into a deionized (DI) water solution containing 5 wt.% MgSO4. The fiber was further immersed in water for 24 hours (to remove the NMP solvent) and then air-dried. A photograph of the fiber cross section is shown in Figure 3. The black areas in the cross section represent the cross sections of the reinforcement polyester yarn.

[0124] Sections of the fiber were tested for their CO2 adsorption properties in a TGA instrument. The fiber was first heated to 110°C and held at 110°C for 30 minutes under nitrogen to activate the fiber. Following this, the activated fiber was cooled to 30°C under nitrogen. The fiber was then exposed to a stream of dry CO2 gas for 30 minutes. The weight gain of the fiber after CO2 exposure was 6.3 wt%. A TGA graph showing the activation of the adsorbent fiber at 110°C and the adsorption of CO2 at 30°C is shown in Figure 4.

[0125] Example 2 (Comparative) A dope solution was prepared by mixing 21.3 g of CALF-20 powder, 7.33 g of polyacrylonitrile, and 40.0 g of NMP. After degassing, the dope solution was transferred to a homemade fiber-spinning apparatus equipped with a spinneret. The dope solution was extruded through the spinneret to form a nascent fiber, which was then pumped into deionized (DI) water. The fiber was further immersed in water for 24 hours (to remove the NMP solvent) and then air-dried.

[0126] A section of the fiber was tested for its CO2 adsorption properties in a TGA instrument. The fiber was first heated to 110°C and held at 110°C for 30 minutes under nitrogen to activate the fiber. Following this, the activated fiber was cooled to 30°C under nitrogen. The fiber was then exposed to a stream of dry CO2 gas for 30 minutes. The weight gain of the fiber after CO2 exposure was 10.7 wt%.

[0127] Attempts to wrap CLAF-20 / PAN fiber (without reinforcing yarn) around a 3 / 8" (approximately 0.95 cm) rod failed. Instead, the fiber fragmented upon bending.

[0128] Example 3 A dope solution was prepared by mixing 21.3 g of CALF-20 powder, 7.33 g of polyacrylonitrile, and 40.0 g of NMP. After degassing, the dope solution was transferred to a fiber-spinning apparatus equipped with a spinneret and a polyester yarn (black TEX21, spun polyester, with a diameter of approximately 0.005 inches (approximately 0.013 cm)) feeder. The dope solution and yarn were extruded through the spinneret to form a nascent fiber, which was then transported into deionized (DI) water. The fiber was further soaked in water for 24 hours (to remove the NMP solvent) and then air-dried.

[0129] A photograph of the cross section of the fiber is shown in Figure 5. The black areas in the cross section are the cross sections of the reinforcing polyester threads.

[0130] FIG. 6 shows that the soft CALF-20 / PAN fabric reinforced with polyester yarn can be easily wrapped around a 3 / 8 inch (about 0.95 cm) rod.

[0131] Fiber sections were tested for their CO2 adsorption properties in a TGA instrument. The fibers were first heated to 110°C and held at 110°C for 30 minutes under nitrogen to activate the fibers. Following this, the activated fibers were cooled to 30°C under nitrogen. The fibers were then exposed to a stream of dry CO2 gas for 30 minutes. The weight gain of the fibers after CO2 exposure was 10.4 wt%. Figure 7 shows a comparison of the pure CO2 adsorption profiles at 30°C of pure CALF-20 powder, CALF-20 / PAN fibers (without yarn), and CALF-20 / PAN fibers (reinforced with polyester yarn). The results showed that the reinforcing yarn in the porous PAN matrix did not adversely affect the adsorption capacity and kinetics compared to unreinforced CALF-20 fibers. Both fibers (with and without reinforcing yarn) also performed better than pure CALF-20 powder.

[0132] While the present invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention as encompassed by the appended claims.

Claims

1. 1. A method for removing acid gases from a fluid stream containing acid gases, comprising: contacting the fluid stream with reinforced porous adsorbent fibers, the reinforced porous adsorbent fibers comprising reinforcing yarns partially or completely embedded in a fibrous adsorbent component, whereby at least a portion of the acid gases are adsorbed by the reinforced porous adsorbent fibers to produce a purified fluid stream. wherein the fibrous adsorbent component comprises an active adsorbent dispersed in a porous matrix.

2. The reinforced porous adsorbent fibers are co-extruding a reinforcing yarn with a first solution containing a water-insoluble polymer and the active adsorbent to produce a yarn-reinforced nascent fiber; introducing the yarn-reinforced nascent fibers into an aqueous solution to form yarn-reinforced coagulated adsorbent fibers; Optionally, washing the yarn-reinforced coagulated adsorbent fibers; drying the optionally washed yarn-reinforced coagulated adsorbent fibers to produce the reinforced porous adsorbent fibers; Optionally, heating the dried reinforced porous adsorbent fibers to produce heat-treated reinforced porous adsorbent fibers.

10. The method of claim 1, wherein the compound is prepared by a method comprising:

3. 3. The method of claim 2, wherein the first solution is prepared using a polar solvent selected from the group consisting of DMF, DMAc, NMP, DMSO, THF, ethanol, propanol, and mixtures of any of the foregoing.

4. 3. The method of claim 2, wherein the water-insoluble polymer is selected from the group consisting of polysulfone, polyimide, cellulose, polyacrylonitrile, polyvinyl difluoride, polyvinyl chloride, polyvinyl butyral, and mixtures of any of these.

5. 10. The method of claim 1, wherein the active adsorbent is polyethyleneimine or the active adsorbent is polyvinylamine.

6. 10. The method of claim 1, wherein the activated adsorbent is a solid adsorbent particle selected from the group consisting of zeolites, MOFs, COFs, PAFs, activated alumina, carbon, graphene, silica, and LDHs.

7. 10. The method of claim 1, wherein the activated adsorbent is an amine-loaded solid adsorbent particle selected from the group consisting of zeolites, MOFs, COFs, PAFs, activated alumina, carbon, graphene, silica, and LDHs.

8. 2. The method of claim 1, wherein the activated adsorbent is a MOF-based solid adsorbent particle selected from the group consisting of CALF-20, UTSA-16, MUF-16, MIL-120(Al) and epn-Mg(dobpdc).

9. 10. The method of claim 1, wherein the reinforcing yarn is a monofilament or braid of PET, PAN, polyimide, polyamide, cotton, carbon, steel, copper, nichrome, or aluminum.

10. The acid gas is CO ２ , S.O. ２ or H ２ The method of claim 1, wherein S is

11. 1. A method for preparing porous reinforced adsorbent fibers, comprising: co-extruding a first solution and a reinforcing yarn, said first solution containing a water-insoluble polymer and an active adsorbent; contacting the first solution with an aqueous solution to form solid, reinforced fibers; Optionally, washing the solid reinforcing fibers; drying the optionally washed solid reinforced fibers to produce porous reinforced adsorbent fibers; A method comprising:

12. 12. A porous reinforced adsorbent fiber prepared by the method of claim 11.

13. 13. The porous reinforced adsorbent fiber of claim 12, wherein the active adsorbent is polyethyleneimine or the active adsorbent is polyvinylamine.

14. 13. The porous reinforced adsorbent fiber of claim 12, wherein the active adsorbent is a solid adsorbent in particulate form selected from the group consisting of zeolites, MOFs, COFs, PAFs, activated alumina, carbon, graphene, silica, and LDHs.

15. 13. The porous reinforced adsorbent fiber of claim 12, wherein the active adsorbent is an amine-loaded solid adsorbent in particulate form, the solid adsorbent being selected from the group consisting of zeolites, MOFs, COFs, PAFs, activated alumina, carbon, graphene, silica, and LDHs.

16. 13. The porous reinforced adsorbent fiber of claim 12, wherein the active adsorbent is a MOF-based solid adsorbent in particulate form, and the MOF-based solid adsorbent is selected from the group consisting of CALF-20, UTSA-16, MUF-16, MIL-120(Al), and epn-Mg(dobpdc).

17. 13. The porous reinforced adsorbent fiber of claim 12, wherein the reinforcing yarn is a monofilament or braided yarn made from a material selected from the group consisting of PET, PAN, polyimide, polyamide, cotton, carbon, steel, copper, nichrome, and aluminum.

18. 13. The porous reinforced adsorbent fiber of claim 12, wherein the first solution is prepared using a polar solvent selected from the group consisting of DMF, DMAc, NMP, DMSO, THF, ethanol, propanol, and mixtures of any of these.

19. 13. The porous reinforced adsorbent fiber of claim 12, wherein said water-insoluble polymer is selected from the group consisting of polysulfone, polyimide, cellulose, polyacrylonitrile, polyvinyl difluoride, polyvinyl chloride, polyvinyl butyral, and mixtures of any of these.

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