Structure, preparation and application of lithium extraction resins

Abstract

The present disclosure provides a lithium ion selective resin containing an alkoxy grafted 2-hydroxybenzophenone (or aldehyde) based functional group, and a preparation method and application thereof. The lithium ion selective resin of the present disclosure has strong chemical structure stability and high lithium-sodium separation factor in a wide pH range.

Description

Technical Field

[0001] This invention relates to the field of lithium extraction materials, and particularly to the structure, preparation, and application of lithium extraction resins. More specifically, this invention relates to the structure, preparation method, and process scheme for extracting lithium from aqueous solutions using a lithium-ion-specific selective ion exchange resin grafted with phenolic ketone functional groups. Background Technology

[0002] The rapid development of electric vehicles has led to a surge in demand for lithium-ion batteries. Lithium, as an irreplaceable chemical element in the production of lithium-ion batteries, is becoming a strategic resource in competition among countries worldwide. The efficient extraction of lithium from ores and brines is receiving widespread attention. The development of any type of lithium ore inevitably involves the extraction of lithium from aqueous solutions containing alkali and alkaline earth metals. Therefore, developing separation materials with specific selectivity for lithium is a key focus for efficient lithium extraction.

[0003] Methods for extracting lithium salts from lithium-containing aqueous solutions mainly include precipitation, adsorption, ion exchange, electrodialysis membrane methods, nanofiltration membrane methods, and solvent extraction. Among these, adsorption and membrane methods are widely used due to their advantages such as high selectivity, simple processes and equipment, continuous operation, and ease of automation. Currently, most lithium adsorbents used are inorganic, including aluminum-based lithium adsorbents such as aluminum hydroxide or lithium aluminum bis hydroxide, manganese dioxide or lithium manganate-based manganese series lithium adsorbents, metatitanic acid or lithium titanate-based titanium-based lithium adsorbents, or manganese-titanium-based lithium adsorbents. In addition, electroadsorption or rocking chair battery lithium extraction systems containing the above-mentioned inorganic lithium adsorbent materials have also shown excellent application prospects. However, when these inorganic materials are used to extract lithium from lithium-containing aqueous solutions, hydration, swelling, and dissolution processes inevitably occur, leading to adsorbent loss or structural failure, shortening the material's energy efficiency and service life.

[0004] Organic polymer ion exchange resins possess superior mechanical properties, durability, and acid resistance compared to inorganic adsorbents. However, to date, very few pure organic polymer ion exchange resins with specific lithium-ion selectivity have been disclosed. Patent CN108421539 discloses an organic resin for separating lithium and sodium, utilizing single exchange groups such as sulfonic acid groups, phosphate groups, and carboxylic acid groups, or aminodicarboxylic acid chelating groups to achieve selective separation of lithium. However, due to the low lithium-sodium separation factor, a complex ion exchange process and equipment are required, and sodium washing with a lithium-containing solution is typically necessary, making the application process quite complex. Patents CN113423499 and CN102786616 disclose organic polymer lithium extraction materials grafted with crown ethers, utilizing the crown 4 structure to achieve specific selection of lithium, with a lithium-sodium separation factor approaching 10. SuperLig has launched SuperLig 80 molecularly imprinted lithium extraction resin [Izatt et al., Metal separations of interest to the Chinese metallurgical industry, JOURNAL OF RARE EARTHS, Vol. 28, Spec. Issue, Dec. 2010, pp. 22-29. Izatt et al., Handbook of Green Chemistry: Online, 2018, pp. 219-220]. Ventura et al. reported a tetramethyl methacrylate chelate lithium extraction resin prepared by ion imprinting [Ventura et al., Selective Recovery of Lithium from Brines, PROCEEDINGS, 43rd Workshop on Geothermal Reservoir Engineering], but when the sodium-lithium ratio is close to 20, the lithium-sodium separation factor of this resin is only 3.5.

[0005] Therefore, there is still a need to develop a reagent and method that can efficiently separate lithium from alkali metals and alkaline earth metals. Summary of the Invention

[0006] To address the challenge of efficiently separating lithium from alkali and alkaline earth metals, the inventors, through long-term experimental research, discovered that 2-hydroxybenzophenone (or aldehyde) functional groups possess an extremely strong chelating ability for lithium, enabling effective separation of lithium from alkali metals such as sodium, potassium, rubidium, and cesium, and alkaline earth metals such as magnesium, calcium, and strontium. Furthermore, they developed ion exchange resin materials containing alkoxy-grafted 2-hydroxybenzophenone (or aldehyde) functional groups. The resin disclosed herein exhibits strong chemical structural stability and a high lithium-sodium separation factor across a wide pH range.

[0007] The first aspect of this disclosure provides a lithium-ion selective resin material comprising at least one 2-hydroxybenzophenone (or aldehyde) functional group having the structure of formula (I), wherein:

[0008] R1 is hydrogen, an optionally substituted C1-C4 alkyl group, or an optionally substituted benzene group, wherein the substitution is made by a group selected from the group consisting of: C1-C4 alkyl, C1-C4 alkoxy, halogen, and phenyl.

[0009]

[0010] R2, R3, R4, and R5 are each independently hydrogen, halogen, nitro, benzyloxy, or C. 1-4 Alkyl, C 1-4 An alkoxy group or a linker group, provided that at least one of R2, R3, R4 and R5 is a linker group, which covalently links the structure of formula (I) to the polymer backbone.

[0011] A second aspect of this disclosure provides a method for extracting lithium, including...

[0012] The lithium-ion selective resin of the first aspect is brought into contact with a lithium-containing solution, and then the lithium-ion selective resin is separated.

[0013] A third aspect of this disclosure provides a method for preparing lithium-ion selective resins via a grafting reaction, comprising: using a halogenated polymer matrix and a lithium chelating functional monomer as raw materials, and employing an etherification grafting reaction to covalently link the lithium chelating functional monomer to the polymer matrix, thereby forming lithium-ion selective resin spheres or particles.

[0014] The fourth aspect of this disclosure provides a method for preparing lithium-ion selective resins via copolymerization, comprising: using a lithium-chelating functional monomer bonded with 4-vinylbenzyl ether as a raw material, copolymerizing it with 4-vinylstyrene and divinylbenzene to prepare lithium-ion selective resin balls or particles. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention.

[0016] Figure 1 The dynamic lithium extraction performance of the lithium extraction resin 8P3 prepared in Example 11 is shown in the test of low sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines.

[0017] Figure 2 The dynamic lithium extraction performance of the lithium extraction resin 8P3 prepared in Example 11 is shown in the test of high sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines.

[0018] Figure 3 The cycling performance of the lithium extraction resin of Example 24 is shown.

[0019] Figure 4 The infrared spectrum of the lithium extraction resin of Example 25 is shown.

[0020] Figure 5 A micrograph of the pre-grafting skeleton resin of Example 26 is shown.

[0021] Figure 6 A micrograph of the grafted lithium-extracting resin of Example 26 is shown. Detailed Implementation

[0022] All publications and patents mentioned in this disclosure are incorporated herein by reference in their entirety. If any use or terminology used in any publications and patents incorporated by reference conflicts with the use or terminology used in this invention, the use and terminology of this invention shall prevail.

[0023] The chapter titles used in this article are for organizational purposes only and should not be construed as limiting the subject matter.

[0024] Unless otherwise specified, all technical and scientific terms used herein have their usual meaning in the field to which the claimed subject matter pertains. Where multiple definitions exist for a term, the definition herein shall prevail.

[0025] Unless otherwise indicated in the working embodiments or elsewhere, all numerical figures for quantitative qualities such as dosages set forth in the specification and claims shall be understood to be modified in all cases by the term “about”. It should also be understood that any numerical ranges enumerated in this application are intended to include all subranges within that range and any combination of the endpoints of that range or subranges, for example, integers 1-20 include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20, and also include subranges 1-3, 1-4, 1-10, 2-4, 2-10, etc.

[0026] As used herein, the words “comprising,” “containing,” or “including” mean that the element preceding the word encompasses the elements listed following the word and their equivalents, without excluding elements not described. The terms “containing” or “comprising (including)” as used herein can be open-ended, semi-closed, or closed-ended. In other words, the terms also include “consistently composed of” or “composed of”.

[0027] The term "optional" in this disclosure means that the described situation may or may not occur.

[0028] This invention may be implemented in other specific forms without departing from its essential attributes. It should be understood that, without conflict, any and all embodiments of this invention can be combined with technical features of any or more other embodiments to obtain further embodiments. This invention includes such further embodiments obtained through combinations.

[0029] This disclosure should be interpreted as consistent with the laws and principles of chemical bonding. In some cases, it may be necessary to remove a hydrogen atom to accommodate a substituent at a given position.

[0030] In this disclosure, the term "alkyl" refers to a branched or straight-chain monovalent hydrocarbon group having n carbon atoms and 2n+1 hydrogen atoms. C1-C4 alkyl refers to a straight-chain or branched saturated monovalent hydrocarbon group having 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl. In one embodiment, the C1-C4 alkyl group is preferably straight-chain, i.e., methyl, ethyl, propyl, and n-butyl.

[0031] The term "alkoxy" in this disclosure refers to an alkyl group as defined above, which is attached to the parent structure by an oxygen atom. Typical alkyl groups include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, isobutoxy, tert-butoxy, pentooxy, isopentoxy, neopentoxy, hexoxy, heptoxy, octoxy, 2-ethylhexoxy, nonoxy, decoxy, dodecyloxy, hexadecyloxy, etc.

[0032] The term "nitro" in this disclosure refers to the -NO2 group.

[0033] The term "benzyloxy" in this disclosure refers to the monovalent group PhCH2O- remaining after benzyl alcohol loses a hydrogen atom from its hydroxyl group.

[0034] The term "halogenated" or "halogen" in this disclosure refers to fluorine, chlorine, bromine, or iodine. In some embodiments, "halogenated" or "halogen" is chlorine or bromine. In other embodiments, "halogenated" or "halogen" is fluorine.

[0035] This disclosure provides a lithium-ion selective resin comprising at least one 2-hydroxyphenyl ketone (or aldehyde) functional group having the structure of formula (I), wherein:

[0036] R1 is hydrogen, an optionally substituted C1-C4 alkyl group, or an optionally substituted benzene group, wherein the substitution is made by a group selected from the group consisting of: C1-C4 alkyl, C1-C4 alkoxy, halogen, and phenyl.

[0037]

[0038] R2, R3, R4, and R5 are each independently hydrogen, halogen, nitro, benzyloxy, or C. 1-4 Alkyl, C 1-4 An alkoxy group or a linker group, provided that at least one of R2, R3, R4 and R5 is a linker group, which covalently links the structure of formula (I) to the polymer backbone.

[0039] Optionally, R1 in the structure of formula (I) is hydrogen, methyl or benzene.

[0040] In one implementation, one of R2 to R5 in the structure of formula (I) is a linker, and the rest are all H.

[0041] In another embodiment, one of R2 to R5 in the structure of formula (I) is a nitro group. Preferably, R2 to R5, except for the nitro group and the linking group, are H.

[0042] Preferably, the linking groups in R2 to R5, which are connected to the polymer backbone, are ether bonds, thereby grafting the molecular structure containing formula (I) onto the polymer backbone. For example, lithium-ion selective resins have a structure of formulas (II) to (V):

[0043]

[0044] In one embodiment, the R1 group in the structures shown in formulas (II) to (V) is hydrogen, methyl or benzene, and all R2 to R4 are H.

[0045] In another embodiment, the R1 group in the structures shown in formulas (II) to (V) is hydrogen, methyl or benzene, one of R2 to R4 is nitro, and the rest are all H.

[0046] Preferably, the polymer backbone is a polymer capable of halomethylation or halogenation.

[0047] For example, the polymer backbone is styrene-divinylbenzene copolymer, polyvinyl chloride, polyphenylene ether, polyether ether ketone, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene propylene rubber-styrene-acrylonitrile copolymer, acrylonitrile-butyl acrylate-styrene copolymer, acrylonitrile-vinyl chloride-styrene copolymer, (meth)acrylate-butadiene-styrene copolymer, or styrene-butene copolymer.

[0048] In one embodiment, the degree of crosslinking of the polymer backbone of the lithium-ion selective resin is 0–7 wt.%.

[0049] In one embodiment, the polymer backbone of the lithium-ion selective resin has a gel structure or a macroporous structure. Preferably, the polymer backbone is spherical. For example, the diameter of the spheres in the polymer backbone is 0.1–1.5 mm, 0.2–1.2 mm, or 0.5–1.5 mm.

[0050] In one embodiment, the polymer backbone of the lithium-ion selective resin is particulate. Preferably, the particle size of the polymer backbone particles is 12-160 mesh, for example, 15-150 mesh, 20-100 mesh, or 50-100 mesh.

[0051] In one embodiment, the 2-hydroxybenzophenone (or aldehyde) functional group having the structure of formula (I) is derived from a lithium chelating functional monomer selected from: 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxyphenylacetone, 2,4-dihydroxyphenylbutanone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxyphenylacetone, 2,6-dihydroxyphenylbutanone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-phenylacetone, 2,4-dihydroxy-5-nitro-phenylacetone, 2,4-dihydroxy-5-nitro-phenylbutanone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzaldehyde One or a mixture of several of the following: 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzophenone, or halogenated derivatives of these substances. For example, lithium chelating functional monomers can be grafted onto the resin with 2-hydroxybenzophenone (or aldehyde) functional groups having the structure of formula (I) by ether bonding with the polymer backbone.

[0052] In one embodiment, the grafting amount of the lithium chelating functional monomer is 0.01–5 mmol / g resin, for example 0.1–1 mmol / g resin, 0.5–3 mmol / g resin, or 1.5–4.5 mmol / g resin.

[0053] In one embodiment, the lithium-ion selective resin material further comprises modifying groups that improve hydrophilicity. Preferably, the modifying groups that improve hydrophilicity include one or more of the following: sulfonic acid group, carboxylic acid group, phosphate group, phenolic hydroxyl group, alcoholic hydroxyl group, iminodiacetic acid group, primary amine group, secondary amine group, and quaternary ammonium group.

[0054] For example, the modifying groups that improve hydrophilicity are derived from benzenesulfonic acid, benzoic acid, benzyl alcohol, acrylic acid, aminophosphoric acid, iminodiacetic acid, phenol, allyl alcohol, trimethylamine quaternary ammonium salt, triethylamine quaternary ammonium salt, triethanolamine quaternary ammonium salt, or triisopropanolamine quaternary ammonium salt.

[0055] In one embodiment, the amount of the modifying group that improves hydrophilicity is grafted is 0 to 3 mmol / g resin, for example, 0.1 to 1 mmol / g resin or 0.5 to 2.5 mmol / g resin.

[0056] Preferably, the lithium-ion selective resin further contains cation exchange groups or anion exchange groups.

[0057] In one embodiment, the lithium-ion selective resin further contains covalently bonded neutral chelating functional groups. Preferably, the neutral chelating functional group is a ketone, ester, phosphine oxide, or crown ether. For example, the neutral chelating functional group is ethyl benzoate, (2-hydroxybenzyl)diphenylphosphine oxide, 2,5-dihydroxyphenyldiphenylphosphine oxide, benzo

[12] crown[4] or / and dibenzo

[14] crown[4].

[0058] In one embodiment, the amount of neutral chelating functional group grafted is 0–3 mmol / g resin, for example, 0.1–0.5 mmol / g resin or 0.5–2.5 mmol / g resin.

[0059] Preferably, the lithium-ion selective resin has a lithium saturation exchange capacity of 0.05 to 1 mmol / g resin, for example, 0.1 to 0.9 mmol / g resin.

[0060] This disclosure also provides a method for extracting lithium, comprising contacting the above-mentioned lithium-ion selective resin with a lithium-containing solution, and then separating the lithium-ion selective resin.

[0061] The aforementioned lithium-ion selective resin can be used to extract lithium from lithium-containing aqueous solutions. These lithium-containing aqueous solutions are, for example, neutral or alkaline salt lake brines with low magnesium and calcium content, geothermal brine, or lithium carbonate or lithium phosphate precipitation mother liquor.

[0062] For example, the pH of an aqueous solution containing lithium ions is 5–13, preferably 8–12.5. For alkaline natural brine, it can be directly contacted with a lithium-ion selective resin, allowing the lithium ions in the brine to be loaded onto the lithium-ion selective resin; for lithium-containing aqueous solutions with pH < 7, the pH and alkalinity can be adjusted to 8–13 by adding alkali metal or ammonium hydroxides, carbonates, phosphates, or borates.

[0063] The method for extracting lithium may further include a step of regenerating the resin after contacting it with a lithium-containing solution. For example, a descaling agent may be used to react with the lithium-ion-loaded lithium-ion-selective resin, thereby allowing the lithium ions to enter the descaling agent and simultaneously enabling the lithium-ion-selective resin to extract lithium from the lithium-containing aqueous solution again; the descaling agent is an aqueous solution of an acid, preferably one or more of carbonic acid, sulfuric acid, sulfurous acid, hydrochloric acid, nitric acid, and phosphoric acid.

[0064] This disclosure also provides a method for preparing lithium-ion selective resins via grafting reactions, comprising: using a halogenated polymer matrix and a lithium chelating functional monomer as raw materials, and employing an etherification grafting reaction to covalently link the lithium chelating functional monomer to the polymer matrix, thereby forming lithium-ion selective resin spheres or particles.

[0065] In one embodiment, the etherification grafting reaction is as follows: using at least one of acetone, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide as a solvent, and at least one of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate as a base; the molar ratio of the lithium chelating functional monomer to the halogen in the polymer matrix is ​​0.2–1.2, for example, 0.5–1.0; the molar ratio of the base to the lithium chelating functional monomer is 0.2–1.2, for example, 0.5–1.0; the amount of solvent used is 2–20 times, for example, 2–5 times, the mass of the polymer matrix; the grafting reaction temperature is 40–120°C, for example, 40–90°C; and the reaction time is 2–72 h, for example, 2–8 h.

[0066] Preferably, the method for preparing the lithium-ion selective resin further includes recovering the solvent by filtration after the grafting reaction is completed, and the recovered solvent is recycled.

[0067] For example, the polymer matrix is ​​a spherical chloromethylated styrene-divinylbenzene copolymer. Preferably, the spherical chloromethylated styrene-divinylbenzene copolymer also contains sulfonic acid groups, phosphonic acid groups, or carboxylic acid groups.

[0068] In one embodiment, the spherical chloromethylated styrene-divinylbenzene copolymer has a chlorine content of 5 to 30 wt%, for example, 5 to 10 wt%.

[0069] In one embodiment, the degree of crosslinking of the spherical chloromethylated styrene-divinylbenzene copolymer is 0 to 5%, for example, 0.5 to 2%.

[0070] For example, the spherical chloromethylated styrene-divinylbenzene copolymer can be prepared by chloromethylation of styrene-divinylbenzene copolymer white spheres.

[0071] In one embodiment, tetrabutylammonium chloride, tetrabutylammonium bromide, or tetrabutylammonium iodide is added as a phase transfer catalyst in the etherification grafting reaction.

[0072] Preferably, potassium iodide is added as a catalyst in the etherification grafting reaction.

[0073] This disclosure also provides a method for preparing lithium-ion selective resins via copolymerization, comprising: copolymerizing a 4-vinylbenzyl ether-bonded lithium-chelating functional monomer with 4-vinylstyrene and optionally divinylbenzene to prepare lithium-ion selective resin balls or particles. Here, optional divinylbenzene means that divinylbenzene may or may not be present.

[0074] Preferably, the copolymerization to prepare resin spheres or granules is performed using suspension polymerization. For example, a 4-vinylbenzyl ether-bonded lithium chelating functional monomer is mixed with liquid styrene, optionally divinylbenzene, and an initiator. Then, under heating conditions, the mixture is added dropwise to an aqueous solution containing a salt such as sodium chloride and a dispersing agent such as polyvinyl alcohol. The reaction is carried out under vigorous stirring to obtain spherical or granular lithium-ion selective resin. The initiator can be, for example, an oil-soluble initiator such as azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovalerate, azodicyclohexylformonitrile, dimethyl azobisisobutyrate, or benzoyl peroxide. Preferably, the molar ratio of styrene to the 4-vinylbenzyl ether-bonded lithium chelating functional monomer is 0.2–3, for example, 0.5–2. Preferably, the divinylbenzene is 0–7% of the total weight of styrene and the 4-vinylbenzyl ether-bonded lithium chelating functional monomer. When divinylbenzene is 0% of the total weight of lithium chelating functional monomers bonded to styrene with 4-vinylbenzyl ether, that is, divinylbenzene is not added in the copolymerization reaction.

[0075] The lithium chelating functional monomer bonded to 4-vinylbenzyl ether can be prepared by reacting the lithium chelating functional monomer of formula (VI) with 4-vinylbenzyl chloride to form an ether.

[0076]

[0077] R1 is hydrogen, an optionally substituted C1-C4 alkyl group, or an optionally substituted benzene group, wherein the substitution is made by a group selected from the group consisting of: C1-C4 alkyl, C1-C4 alkoxy, halogen, and phenyl.

[0078] R2, R3, R4, and R5 are each independently a hydroxyl group, hydrogen, halogen, nitro group, benzyloxy group, or C group. 1-4 Alkyl or C 1-4 Alkoxy group, provided that at least one of R2, R3, R4, and R5 is a hydroxyl group. For example, R3 or R5 is a hydroxyl group.

[0079] Exemplary lithium-chelating functional monomers of formula (VI) may include: 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxyphenylacetone, 2,4-dihydroxybutanone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxyphenylacetone, 2,6-dihydroxyphenylacetone, 2,6-dihydroxybutanone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-phenylacetone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzaldehyde, 2,4-dihydroxy- One or a mixture of several of the following: 3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-phenylbutanone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-phenylbutanone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-phenylbutanone, and 2,6-dihydroxy-5-nitro-benzophenone.

[0080] The lithium chelating functional monomer of formula (VI) reacts with 4-vinylbenzyl chloride to form an ether, for example, in the presence of one or more bases such as lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate.

[0081] In one embodiment, the copolymerization reaction further includes copolymerizing a lithium-chelating functional monomer bonded to 4-vinylbenzyl ether with a monomer for improving the hydrophilicity of the lithium-ion selective resin, styrene, and optionally divinylbenzene. Preferably, the monomer added in the copolymerization method for preparing the lithium-ion selective resin to improve the hydrophilicity of the lithium-ion selective resin is 0–3 mmol / g resin, for example, 0.1–1 mmol / g resin or 0.5–2.5 mmol / g resin.

[0082] Monomers used to improve the hydrophilicity of lithium-ion selective resins may contain modifying groups that improve hydrophilicity, such as one or more of sulfonic acid groups, carboxylic acid groups, phosphate groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, iminodiacetic acid groups, primary amine groups, secondary amine groups, and quaternary ammonium groups.

[0083] Examples of monomers used to improve the hydrophilicity of lithium-ion selective resins include 4-vinylbenzenesulfonic acid (sodium), 4-vinylbenzoic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride, or 4-vinylbenzyl alcohol.

[0084] In one embodiment, the copolymerization reaction further includes the addition of a lithium chelating functional monomer bonded to 4-vinylbenzenesulfonic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride or 4-vinylbenzyl alcohol and 4-vinylbenzyl ether, styrene, and divinylbenzene to improve the hydrophilicity of the lithium-ion selective resin.

[0085] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, specific embodiments of the present invention are described clearly and completely below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Based on the described embodiments of the present invention, all other implementations obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0086] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0087] Unless otherwise defined, the technical or scientific terms used in the following embodiments should have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains.

[0088] Example 1

[0089] Grafting 2,4-dihydroxybenzophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content 0.5%, chlorine content 20 wt%) was placed in a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours. Then, 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added, and the mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 62 g of wet-extracted lithium resin with a water content of 33 wt.%, denoted as lithium-extracted resin 1.

[0090] Example 2

[0091] Grafting 2,4-dihydroxy-5-nitro-benzophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, 0.5% divinylbenzene content, 20 wt% chlorine content) was placed in a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours. Then, 90 mmol of 2,4-dihydroxy-5-nitro-benzophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added. The mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 69 g of wet-extracted lithium resin with a water content of 34 wt.%, designated as lithium-extracted resin 2.

[0092] Example 3

[0093] Grafting 2,4-dihydroxyacetophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content 0.5%, chlorine content 20 wt%) was placed in a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours. Then, 90 mmol of 2,4-dihydroxyacetophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added, and the mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 55 g of wet-extracted lithium resin with a water content of 33 wt.%, designated as lithium-extracted resin 3.

[0094] Example 4

[0095] Grafting 2,4-dihydroxy-5-nitro-acetophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content 0.5%, chlorine content 20 wt%) was placed in a 250 mL spherical reaction flask, and 120 mL of N,N-dimethylformamide (DMF) was added. The mixture was stirred and swollen at room temperature for 2 hours. Then, 90 mmol of 2,4-dihydroxy-5-nitro-acetophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added. The mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 67 g of wet-extracted lithium resin with a water content of 34 wt.%, designated as lithium-extracted resin 4.

[0096] Example 5

[0097] Grafting 2,4-dihydroxy-5-nitro-acetophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<14 mesh, 2% divinylbenzene content, 15 wt% chlorine content) was placed in a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours. Then, 70 mmol of 2,4-dihydroxy-5-nitro-acetophenone, 80 mmol of potassium carbonate, and 0.5 g of potassium iodide were added. The mixture was heated to 70 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 49 g of wet-extracted lithium resin with a water content of 28 wt.%, designated as lithium-extracted resin 5.

[0098] Example 6

[0099] Grafting 2,4-dihydroxy-5-nitro-acetophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<14 mesh, 5% divinylbenzene content, 15 wt% chlorine content) was placed in a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours. Then, 70 mmol of 2,4-dihydroxy-5-nitro-acetophenone, 80 mmol of potassium carbonate, and 0.5 g of potassium iodide were added, and the mixture was heated to 70 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 44 g of wet-extracted lithium resin with a water content of 19 wt.%, designated as lithium-extracted resin 6.

[0100] Example 7

[0101] Grafting 2,4-dihydroxy-5-nitro-acetophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<100 mesh, divinylbenzene content 0.5%, chlorine content 20 wt%) was placed in a 250 mL spherical reaction flask, and 120 mL of N,N-dimethylformamide (DMF) was added. The mixture was stirred and swollen at room temperature for 2 hours. Then, 90 mmol of 2,4-dihydroxy-5-nitro-acetophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added. The mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 70 g of wet-extracted lithium resin with a water content of 34 wt.%, designated as lithium-extracted resin 7.

[0102] Example 8

[0103] Grafting 2,4-dihydroxy-5-nitro-benzophenone onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried, spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<100 mesh, divinylbenzene content 0.5%, chlorine content 20 wt%) was placed in a 250 mL spherical reaction flask, and 120 mL of N,N-dimethylformamide (DMF) was added. The mixture was stirred and swollen at room temperature for 2 hours. Then, 60 mmol of 2,4-dihydroxy-5-nitro-benzophenone, 70 mmol of potassium carbonate, and 0.5 g of potassium iodide were added. The mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 70 g of wet-extracted lithium resin with a water content of 34 wt.%, designated as lithium-extracted resin 8.

[0104] Example 9

[0105] Hydrophilic modification of lithium extraction resin 8: Take 30g of washed and dried lithium extraction resin 8 and place it in a 250mL round-bottom flask. Add 100mL of tetrahydrofuran to swell for 2 hours. Then add 20mmol each of trimethylamine hydrochloride and solid sodium hydroxide. Stir the reaction at room temperature for 10 hours. Then filter out the reaction mother liquor. After washing the resin with water several times, the hydrophilic modified lithium extraction resin 8 is obtained, which is denoted as lithium extraction resin 8P1.

[0106] Example 10

[0107] Hydrophilic modification of lithium extraction resin 8: Take 30g of washed and dried lithium extraction resin 8 and place it in a 250mL round-bottom flask. Add 100mL of tetrahydrofuran to swell for 2 hours, then add 20mmol of triethanolamine. Stir the reaction at 50℃ for 10 hours. Then filter out the reaction mother liquor and wash the resin with water several times to obtain the hydrophilic modified lithium extraction resin 8, which is denoted as lithium extraction resin 8P2.

[0108] Example 11

[0109] Neutral co-chelating ligand modification of lithium extraction resin 8: 30g of washed and dried lithium extraction resin 8 was placed in a 250mL round-bottom flask, and 100mL of DMF was added to swell for 2 hours. Then, 40mmol of (2-hydroxybenzyl)diphenylphosphine oxide, 50mmol of potassium carbonate, and 0.5g of potassium iodide were added, and the mixture was heated to 90℃ and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, and the DMF mother liquor was filtered off. The resin beads were washed multiple times with 0.1M dilute sulfuric acid, and then washed multiple times with 0.3M sodium hydroxide solution to obtain 78g of wet lithium extraction resin with a water content of 35wt.%, which was designated as lithium extraction resin 8P3.

[0110] Example 12

[0111] Neutral co-chelating ligand modification of lithium extraction resin 8: 30g of washed and dried lithium extraction resin 8 was placed in a 250mL round-bottom flask, and 100mL of DMF was added to swell for 2 hours. Then, 30mmol of hydroxybenzo

[12] crown[4], 40mmol of potassium carbonate, and 0.5g of potassium iodide were added. The mixture was heated to 90℃ and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin beads were washed multiple times with 0.1M dilute sulfuric acid, followed by multiple washes with 0.3M sodium hydroxide solution to obtain 59g of wet lithium extraction resin with a water content of 33wt.%, denoted as lithium extraction resin 8P4.

[0112] Example 13

[0113] Preparation of sulfonated intermediates of chloromethylated styrene-divinylbenzene copolymer: 200g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content 0.5%, chlorine content 20wt%) was placed in a 1000mL spherical reaction flask, and 1000mL of dichloroethane was added. The mixture was stirred and swollen at room temperature for 2 hours, then heated to 60℃, and 50mL of 98wt% concentrated sulfuric acid was slowly added dropwise while stirring. After 2 hours, the resin turned brown, and the reaction was stopped. The dichloroethane solvent was distilled off under reduced pressure at 60℃, and the resin was washed several times with water until neutral. 30g of 30wt.% sodium hydroxide was added to convert the resin to the sodium form, and then dried at 70℃ to obtain 280g of sulfonated intermediate.

[0114] Example 14

[0115] 20 g of the chloromethylated styrene-divinylbenzene copolymer sulfonated intermediate prepared in Example 13 was placed in a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred and swollen at room temperature for 2 hours. Then, 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added, and the mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. The DMF mother liquor was filtered off, and the resin balls were washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 62 g of wet lithium extraction resin with a water content of 33 wt.%, which was designated as lithium extraction resin 14.

[0116] Example 15

[0117] Grafting 2,4-dihydroxybenzophenone onto polyvinyl chloride (PVC) as the polymer backbone: 20 g of PVC powder (<100 mesh, chlorine content 56-58 wt%) was added to a 250 mL spherical reaction flask, along with 120 mL of N,N-dimethylformamide (DMF). The mixture was stirred at room temperature for 2 hours to dissolve, followed by the addition of 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of cesium carbonate, and 0.5 g of potassium iodide. The mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature, and 500 mL of water was added. The DMF + water mixture was filtered out, and the resin powder was washed multiple times with 0.1 M dilute sulfuric acid, followed by multiple washes with 0.3 M sodium hydroxide solution to obtain 42 g of wet-extracted lithium resin powder, designated as lithium-extracted resin 15.

[0118] Example 16

[0119] Grafting 2,4-dihydroxybenzophenone onto poly(2,6-dimethyl-1,4-phenylene ether) (PPO) as the polymer backbone: 20 g of PPO powder was placed in a 250 mL spherical reaction flask, 120 mL of dichloroethane was added, and the mixture was stirred at room temperature for 2 hours to dissolve. Then, 90 mmol of N-bromosuccinimide (NBS) was added, and the mixture was heated under reflux for 8 hours. The dichloroethane solvent was then distilled off under reduced pressure to obtain bromomethylated PPO. The PPO was then completely dissolved in 150 mL of N,N-dimethylformamide (DMF), and 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were added. The mixture was heated to 90 °C and stirred for 16 hours. After the reaction was completed, the mixture was allowed to cool naturally to room temperature. 500 mL of water was added, and the DMF + water mixture was filtered out. The resin powder was washed multiple times with 0.1 M dilute sulfuric acid, and then washed multiple times with 0.3 M sodium hydroxide solution to obtain 50 g of wet lithium extraction resin powder, which was designated as lithium extraction resin 16.

[0120] Example 17

[0121] Styrene-divinylbenzene-4-(4-vinylbenzoxy)-2-hydroxybenzophenone suspension copolymerization: 1) Preparation of 4-(4-vinylbenzoxy)-2-hydroxybenzophenone monomer: 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of tetrabutylammonium bromide catalyst were added to 200 mL of acetone solvent and heated to 70 °C for half an hour to dissolve. Then, 90 mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was complete, the reaction was carried out for 7 hours. Then, 500 mL of deionized water was added to precipitate the solid product. The product was filtered, washed several times, and dried to obtain 30 g of product for later use. 2) Take 100g of styrene, wash it repeatedly with 10wt% sodium hydroxide aqueous solution to remove the polymerization inhibitor, and set it aside. Take 7g of divinylbenzene, wash it repeatedly with 10wt% sodium hydroxide aqueous solution to remove the polymerization inhibitor, and set it aside. Mix 30g of 4-(4-vinylbenzoxy)-2-hydroxybenzophenone with the 100g of de-inhibited styrene and 7g of divinylbenzene, add 2.5g of benzoyl peroxide, mix well, and then add it dropwise to the aqueous phase of the suspension polymerization under strong stirring. The preparation process of the aqueous phase of the suspension polymerization is as follows: add 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol to a 1000mL round-bottom flask, stir the solution until a homogeneous solution is obtained, the reaction temperature is 80℃, and the polymerization time is 8 hours. After the reaction is complete, filter out the solution to obtain 120g of lithium extraction resin balls, which is denoted as lithium extraction resin 17.

[0122] Example 18

[0123] Styrene-divinylbenzene-4-(4-vinylbenzoxy)-2-hydroxybenzophenone-4-vinylbenzenesulfonic acid suspension copolymerization: 1) Preparation of 4-(4-vinylbenzoxy)-2-hydroxybenzophenone monomer: 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of tetrabutylammonium bromide catalyst were added to 200 mL of acetone solvent and heated to 70 °C for half an hour to dissolve. Then, 90 mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was completed, the reaction was carried out for 7 hours. Then, 500 mL of deionized water was added to precipitate the solid product. The product was filtered, washed several times, and dried to obtain 30 g of product for later use. 2) Take 100g of styrene, wash it repeatedly with 10wt% sodium hydroxide aqueous solution to remove the polymerization inhibitor, and set it aside. Take 7g of divinylbenzene, wash it repeatedly with 10wt% sodium hydroxide aqueous solution to remove the polymerization inhibitor, and set it aside. Mix 30g of 4-(4-vinylbenzeneoxy)-2-hydroxybenzophenone with the removed 100g of styrene, 7g of divinylbenzene, and 10g of 4-vinylbenzenesulfonic acid, add 3.5g of benzoyl peroxide, mix well, and then add it dropwise to the suspension polymerization aqueous phase under strong stirring. The preparation process of the suspension polymerization aqueous phase is as follows: add 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol to a 1000mL round-bottom flask, stir the solution until a homogeneous solution is obtained, the reaction temperature is 90℃, and the polymerization time is 6 hours. After the reaction is complete, filter out the solution to obtain 130g of lithium extraction resin balls, which is denoted as lithium extraction resin 18.

[0124] Example 19

[0125] Styrene-divinylbenzene-4-(4-vinylbenzoxy)-2-hydroxybenzophenone-triethyl(4-vinylbenzyl)ammonium chloride suspension copolymerization: 1) Preparation of 4-(4-vinylbenzoxy)-2-hydroxybenzophenone monomer: 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of tetrabutylammonium bromide catalyst were added to 200 mL of acetone solvent and heated to 70 °C for half an hour to dissolve. Then, 90 mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was complete, the reaction was carried out for 7 hours. Then, 500 mL of deionized water was added to precipitate the solid product. The product was filtered, washed several times, and dried to obtain 30 g of product for later use. 2) Take 100g of styrene, wash it repeatedly with 10wt% sodium hydroxide aqueous solution to remove the polymerization inhibitor, and set it aside. Take 7g of divinylbenzene, wash it repeatedly with 10wt% sodium hydroxide aqueous solution to remove the polymerization inhibitor, and set it aside. Mix 30g of 4-(4-vinylbenzoxy)-2-hydroxybenzophenone with the removed 100g of styrene, 7g of divinylbenzene, and 15g of triethyl(4-vinylbenzyl)ammonium chloride, add 3.5g of benzoyl peroxide, mix well, and then add dropwise to the suspension polymerization aqueous phase under strong stirring. The preparation process of the suspension polymerization aqueous phase is as follows: add 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol to a 1000mL round-bottom flask, stir the solution until a homogeneous solution is obtained, the reaction temperature is 90℃, and the polymerization time is 6 hours. After the reaction is complete, filter out the solution to obtain 137g of lithium extraction resin balls, which is denoted as lithium extraction resin 19.

[0126] Example 20

[0127] Static lithium exchange performance test of the lithium extraction resins prepared in Examples 1-19: 1) The experimental raw material brine was a 0.25 mol / L lithium hydroxide aqueous solution (lithium concentration was 1.73 g / L); 2) In the experiment, 5 g of wet resin was taken, 20 mL of the experimental raw material brine was added, and the mixture was shaken at room temperature for 24 hours. The remaining liquid was diluted and the lithium content was determined by ion chromatography (IC). The exchange capacity was calculated, and the results are listed in Table 1 below:

[0128] Table 1: Static lithium exchange performance of lithium extraction resins prepared in Examples 1-19

[0129] Lithium extraction resin number Equilibrium concentration (g / L) Lithium exchange capacity (mg / g wet resin) 1 1.12 2.44 2 0.86 3.48 3 1.26 1.88 4 0.71 4.08 5 0.79 3.76 6 1.34 1.56 7 0.57 4.64 8 0.57 4.64 8P1 0.22 6.04 8P2 0.21 6.08 8P3 0.25 5.92 8P4 0.30 5.72 14 0.12 6.44 15 1.38 1.40 16 1.27 1.84 17 0.62 4.44 18 0.33 5.60 19 0.47 5.04

[0130] Example 21

[0131] The static lithium / sodium, lithium / potassium, lithium / rubidium, and lithium / cesium separation performance tests of the lithium extraction resins prepared in Examples 1-19: 1) The experimental raw material brine was a mixed aqueous solution of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide (Li... + =0.376g / L, Na + =0.498g / L, K +=0.442g / L, Rb + =0.741g / L, Cs + =1.477g / L, pH=13); 2) In the experiment, 5g of wet resin was taken and 20mL of experimental raw material brine was added. The mixture was shaken at room temperature for 24 hours. The remaining liquid was diluted and the contents of lithium, sodium, potassium, rubidium and cesium were determined by ion chromatography (IC). The separation factor α (A / B) was calculated and the results are listed in Table 2 below.

[0132] Table 2: Static lithium / sodium, lithium / potassium, lithium / rubidium, and lithium / cesium separation performance of the lithium extraction resins prepared in Examples 1-19

[0133] Lithium extraction resin number α(Li / Na) α(Li / K) α(Li / Rb) α(Li / Cs) 1 5.2 8.0 8.8 9.2 2 4.4 6.1 8.7 9.7 3 5.1 7.4 7.3 8.6 4 5.8 7.3 7.2 9.0 5 6.8 9.3 11.2 15 6 7.2 10.1 11.2 14.8 7 3.7 5.4 7.2 8.0 8 3.2 5.1 7.4 8.2 8P1 3.2 5.1 7.4 8.2 8P2 3.0 4.9 7.1 9.2 8P3 10.3 14.4 15.5 18.1 8P4 13.7 20.5 27.3 30.5 14 2.7 4.5 6.1 6.2 15 5.7 8.9 8.3 10.4 16 5.1 8.0 9.2 9.3 17 8.7 10.2 15.5 19.7 18 3.2 4.9 7.2 9.1 19 3.5 5.6 6.3 8.8

[0134] Example 22

[0135] Dynamic lithium extraction performance test of the lithium extraction resin 8P3 prepared in Example 11 (low sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines):

[0136] 1) The experimental brine was a mixed aqueous solution of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide (Li... + =0.376g / L, Na + =0.498g / L, K + =0.442g / L, Rb + =0.741g / L, Cs + =1.477g / L, pH=13); 2) Experimental procedure: Take 60g of wet resin and load it into a container with a diameter of... In a 50 cm long ion exchange column, the experimental brine was passed through the resin column at a flow rate of 1–1.5 mL / min. The eluent was collected in segments, and its composition was analyzed by ion chromatography (IC). The resin column was then washed with water, followed by elution of lithium with 0.1 mol / L hydrochloric acid. The resulting operating curve is shown below. Figure 1 As shown, the system separation factors are α(Li / Na) = 62.89, α(Li / K) = 69.91, α(Li / Rb) = 66.59, and α(Li / Cs) = 42.18.

[0137] Example 23

[0138] Dynamic lithium extraction performance test of the lithium extraction resin 8P3 prepared in Example 11 (high sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines):

[0139] 1) The experimental brine was a real brine containing lithium, sodium, potassium, rubidium, and cesium chloride (Li). + =0.202g / L, Na + =90.350g / L, K +=77.858g / L, Rb + =2.947g / L, Cs + =2.196 g / L, OH - 1) Concentration: 0.2 mol / L; 2) Experimental procedure: Using the resin column from Example 22, the experimental brine was passed through the resin column at a flow rate of 1–1.5 mL / min. The eluent was collected in segments, and its composition was analyzed by ion chromatography (IC). The resin column was then washed with water, followed by elution of lithium with 0.1 mol / L hydrochloric acid. The resulting operating curve is shown below. Figure 2 As shown, the system separation factors are α(Li / Na) = 733.08, α(Li / K) = 1281.99, α(Li / Rb) > 10000, and α(Li / Cs) > 10000.

[0140] Example 24. Cyclic performance of lithium extraction resin

[0141] Take 5g of lithium extraction resin 1 and add 20mL of 0.25mol / L lithium hydroxide aqueous solution (lithium concentration determined by ion chromatography is 1.73g / L). After shaking and reacting for 24 hours, measure the lithium ion concentration in the remaining solution and calculate the amount of lithium exchanged into the resin. Lithium exchange capacity = (Li 原始 -Li 余液 ) g / L × 20 mL / 5 g. Afterwards, the remaining liquid was separated, and 20 mL of 0.2 mol / L hydrochloric acid solution was added for lithium elution and resin regeneration. After shaking and reacting for 24 hours, the eluent was separated and washed with deionized water until neutral, for use in the next lithium exchange capacity determination. The above experimental procedure was repeated 10 times, and the lithium exchange capacity obtained each time was as follows: Figure 3 .

[0142] Example 25. Infrared spectrum of lithium extraction resin

[0143] The infrared spectra of lithium extraction resins 1 and 3 are as follows: Figure 4 As shown. Both lithium extraction resins are graft products of chloromethylated styrene-divinylbenzene spherical copolymers. After grafting, the C-Cl infrared vibration of the chloromethyl group (ν = 670 cm⁻¹) is observed. -1 The characteristic infrared absorption of ether bonds and ketone groups disappeared, while the characteristic infrared absorption of ether bonds and ketone groups (ν = 3020–3050 cm⁻¹) appeared. -1 ν = 1680~1700cm -1 )

[0144] Example 26. Comparison of micrographs of the skeleton resin before grafting and the lithium-extracted resin after grafting.

[0145] Figure 5 Micrographs of styrene-divinylbenzene copolymer backbone resin spheres before grafting. Figure 6Micrographs of lithium-extracting resin spheres grafted onto a styrene-divinylbenzene copolymer backbone. (Comparison) Figure 5 and Figure 6 As can be seen, the resin ball became larger and turned yellow after grafting.

[0146] Example 27. Method for determining exchange capacity (for characterizing grafting effect)

[0147] Take 5g of cleaned and dried lithium extraction resin balls (pressed dry with filter paper), add 20mL of 0.25mol / L lithium hydroxide aqueous solution (lithium concentration 1.73g / L), and incubate at room temperature with shaking for 24 hours. Dilute the remaining solution and determine the lithium content using ion chromatography (IC). Calculate the resin's exchange capacity: Lithium exchange capacity = (Li... 原始 -Li 余液 )g / L×20mL / 5g. Furthermore, the lithium-loaded resin balls were separated and washed twice with water, then titrated with 0.2mol / L hydrochloric acid (methyl orange as an indicator) to determine the acid consumption of the lithium-loaded resin balls, thereby calculating the elution exchange capacity: Lithium exchange capacity = hydrochloric acid titration amount (L) × 0.2mol / L × 6.94 / 5g.

[0148] The above description is merely an exemplary embodiment of the present invention and is not intended to limit the scope of protection of the present invention, which is determined by the appended claims.

Claims

1. A lithium-ion selective resin comprising a polymer backbone and at least one 2-hydroxybenzophenone or 2-hydroxybenzaldehyde functional group, said lithium-ion selective resin comprising a structure selected from formula (II) to (V): Equation (II), Formula (III) Formula (IV), and Formula (V), in, R1 is hydrogen, methyl, or phenyl. All of R2 to R4 are H, or one of R2 to R4 is a nitro group and the rest are all H. The polymer backbone is styrene-divinylbenzene copolymer, polyvinyl chloride, polyphenylene ether, polyetheretherketone, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene propylene rubber-styrene-acrylonitrile copolymer, acrylonitrile-butyl acrylate-styrene copolymer, acrylonitrile-vinyl chloride-styrene copolymer, methyl acrylate-butadiene-styrene copolymer, or methyl methacrylate-butadiene-styrene copolymer, or styrene-butene copolymer. The polymer backbone is a polymer capable of halomethylation or halogenation, and the degree of crosslinking of the polymer backbone is 0–7 wt.%, with a grafting amount of 0.01–5 mmol / g resin. The lithium-ion selective resin further contains covalently bonded neutral chelating functional groups, wherein the neutral chelating functional groups are ester, phosphine oxide, or crown ether functional groups, and the amount of the neutral chelating functional groups grafted is 0–3 mmol / g resin.

2. The lithium-ion selective resin of claim 1, wherein the amount of neutral chelating functional group grafted is 0.1 to 0.5 mmol / g resin.

3. The lithium-ion selective resin of claim 1, wherein the polymer backbone has a gel structure or a macroporous structure.

4. The lithium-ion selective resin of claim 3, wherein the polymer backbone is spherical.

5. The lithium-ion selective resin of claim 4, wherein the diameter of the spheres in the polymer backbone is 0.1 to 1.5 mm.

6. The lithium-ion selective resin of claim 1, wherein the 2-hydroxybenzophenone or 2-hydroxybenzaldehyde functional group is derived from a lithium chelating monomer selected from the following: 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxyphenylacetone, 2,4-dihydroxyphenylbutanone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxyphenylacetone, 2,6-dihydroxyphenylbutanone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-phenylacetone, 2,4-dihydroxy-5-nitro-phenylacetone, 2,4-dihydroxy-5-nitro-phenylbutanone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy- One or a mixture of several of the following: 3-nitrobenzaldehyde, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-butanone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitrobenzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-butanone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitrobenzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, and 2,6-dihydroxy-5-nitro-benzophenone.

7. The lithium-ion selective resin according to any one of claims 1 to 6, further comprising a modifying group for improving hydrophilicity, wherein the modifying group for improving hydrophilicity includes: One or more of the following groups: sulfonic acid group, carboxylic acid group, phosphoric acid group, phenolic hydroxyl group, alcoholic hydroxyl group, iminodiacetic acid group, primary amine group, secondary amine group and quaternary ammonium group.

8. The lithium-ion selective resin of claim 7, wherein the hydrophilicity-improving modifying group is derived from benzenesulfonic acid, benzoic acid, benzyl alcohol, acrylic acid, aminophosphoric acid, iminodiacetic acid, phenol, allyl alcohol, trimethylamine quaternary ammonium salt, triethylamine quaternary ammonium salt, triethanolamine quaternary ammonium salt, or triisopropanolamine quaternary ammonium salt.

9. The lithium-ion selective resin of claim 7, wherein the amount of grafting of the hydrophilicity-improving modifying group is 0 to 3 mmol / g resin.

10. The lithium-ion selective resin of claim 9, wherein the amount of grafting of the hydrophilicity-improving modifying group is 0.1 to 1 mmol / g resin.

11. The lithium-ion selective resin according to any one of claims 1 to 6, wherein, The lithium-ion selective resin also contains cation exchange groups or anion exchange groups.

12. The lithium-ion selective resin according to any one of claims 1 to 6, wherein the neutral chelating functional group is derived from ethyl benzoate, (2-hydroxybenzyl)diphenylphosphine oxide, (2,5-dihydroxyphenyl)diphenylphosphine oxide, benzo[12]crown 4 or / and dibenzo[14]crown 4.

13. The lithium-ion selective resin according to any one of claims 1 to 6, wherein the lithium-ion selective resin has a lithium saturation exchange capacity of 0.05 to 1 mmol / g resin.

14. A method for extracting lithium from a lithium-containing aqueous solution, comprising contacting a lithium-ion selective resin with the lithium-containing solution, and then separating the lithium-ion selective resin. in, The lithium-ion selective resin contains at least one 2-hydroxybenzophenone or 2-hydroxybenzaldehyde functional group having the structure of formula (I). I， in: R1 is hydrogen, an optionally substituted C1-C4 alkyl group, or an optionally substituted benzene group, wherein the substitution is made by a group selected from the group consisting of: C1-C4 alkyl, C1-C4 alkoxy, halogen, and phenyl. R2, R3, R4, and R5 are each independently hydrogen, halogen, nitro, benzyloxy, or C. 1～4 Alkyl, C 1～4 An alkoxy group or a linker group, provided that at least one of R2, R3, R4 and R5 is a linker group, which covalently links the structure of formula (I) to the polymer backbone.

15. The method of claim 14, wherein R1 in the structure of formula (I) is hydrogen, methyl or phenyl.

16. The method of claim 15, wherein one of R2 to R5 in the structure of formula (I) is a linker, and the rest are all H.

17. The method of claim 15, wherein one of R2 to R5 is a nitro group.

18. The method of claim 17, wherein R2 to R5, except for nitro groups and linking groups, are H.

19. The method of claim 14, wherein, The lithium-ion selective resin further comprises a polymer backbone, wherein the linking groups in R2 to R5 connected to the polymer backbone are ether bonds, thereby grafting the molecular structure containing formula (I) onto the polymer backbone.

20. The method of claim 19, wherein, The lithium-ion selective resin comprises a structure selected from formulas (II) to (V): Equation (II), Formula (III) Formula (IV), and Formula (V).

21. The method of claim 20, wherein R1 is hydrogen, methyl or benzene, and R2 to R4 are all H.

22. The method of claim 20, wherein R1 is hydrogen, methyl or benzene; one of R2 to R4 is nitro, and the rest are all H.

23. The method of claim 19, wherein the polymer backbone is a polymer capable of halomethylation or halogenation.

24. The method of claim 23, wherein the polymer backbone is a styrene-divinylbenzene copolymer, polyvinyl chloride, polyphenylene ether, polyetheretherketone, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene propylene rubber-styrene-acrylonitrile copolymer, acrylonitrile-butyl acrylate-styrene copolymer, acrylonitrile-vinyl chloride-styrene copolymer, methyl acrylate-butadiene-styrene copolymer, or methyl methacrylate-butadiene-styrene copolymer, or styrene-butene copolymer.

25. The method of claim 19, wherein the degree of crosslinking of the polymer backbone is 0 to 7 wt.%.

26. The method of claim 19, wherein the polymer backbone has a gel structure or a macroporous structure.

27. The method of claim 26, wherein the polymer backbone is spherical.

28. The method of claim 27, wherein the diameter of the spheres in the polymer backbone is 0.1 to 1.5 mm.

29. The method of claim 14, wherein the 2-hydroxybenzophenone or 2-hydroxybenzaldehyde functional group having the structure of formula (I) is derived from a lithium chelating functional monomer selected from: 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxyphenylacetone, 2,4-dihydroxyphenylbutanone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxyphenylacetone, 2,6-dihydroxyphenylbutanone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-phenylacetone, 2,4-dihydroxy-5-nitro-phenylacetone, 2,4-dihydroxy-5-nitro-phenylbutanone, 2,4-dihydroxy-5-nitro-benzophen ... One or a mixture of several of the following: hydroxy-3-nitro-benzaldehyde, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-butanone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-butanone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-butanone, and 2,6-dihydroxy-5-nitro-benzophenone.

30. The method of claim 29, wherein, The grafting amount of the lithium chelating functional monomer is 0.01–5 mmol / g resin.

31. The method of claim 14, wherein, The lithium-ion selective resin further comprises a modifying group that improves hydrophilicity, wherein the modifying group that improves hydrophilicity includes one or more of the following: sulfonic acid group, carboxylic acid group, phosphate group, phenolic hydroxyl group, alcoholic hydroxyl group, iminodiacetic acid group, primary amine group, secondary amine group and quaternary ammonium group.

32. The method of claim 31, wherein the hydrophilicity-improving modifying group is derived from benzenesulfonic acid, benzoic acid, benzyl alcohol, acrylic acid, aminophosphoric acid, iminodiacetic acid, phenol, allyl alcohol, trimethylamine quaternary ammonium salt, triethylamine quaternary ammonium salt, triethanolamine quaternary ammonium salt, or triisopropanolamine quaternary ammonium salt.

33. The method of claim 31, wherein the amount of grafting of the hydrophilicity-improving modifying group is 0 to 3 mmol / g resin.

34. The method of claim 33, wherein the amount of grafting of the hydrophilicity-improving modifying group is 0.1 to 1 mmol / g resin.

35. The method of claim 14, wherein, The lithium-ion selective resin also contains cation exchange groups or anion exchange groups.

36. The method of claim 14, further comprising a covalently bonded neutral chelating functional group.

37. The method of claim 36, wherein the neutral chelating functional group is an ester, a phosphonium, or a crown ether.

38. The method of claim 37, wherein the neutral chelating functional group is derived from ethyl benzoate, (2-hydroxybenzyl)diphenylphosphine oxide, (2,5-dihydroxyphenyl)diphenylphosphine oxide, benzo[12]crown4 or / and dibenzo[14]crown4.

39. The method of claim 36, wherein the amount of neutral chelating functional group grafted is 0 to 3 mmol / g resin.

40. The method of claim 39, wherein the amount of neutral chelating functional group grafted is 0.1 to 0.5 mmol / g resin.

41. The method of claim 14, wherein the lithium-ion selective resin has a lithium saturation exchange capacity of 0.05 to 1 mmol / g resin.

42. The method of claim 14, further comprising: The step of regenerating the resin after the lithium-ion selective resin has been contacted with a lithium-containing solution.

43. Use of a lithium-ion selective resin for extracting lithium from a lithium-ion solution, wherein the lithium-ion selective resin comprises at least one 2-hydroxybenzophenone or 2-hydroxybenzaldehyde functional group having the structure of formula (I). I， in: R1 is hydrogen, an optionally substituted C1-C4 alkyl group, or an optionally substituted benzene group, wherein the substitution is made by a group selected from the group consisting of: C1-C4 alkyl, C1-C4 alkoxy, halogen, and phenyl. R2, R3, R4, and R5 are each independently hydrogen, halogen, nitro, benzyloxy, or C. 1～4 Alkyl, C 1～4 An alkoxy group or a linker group, provided that at least one of R2, R3, R4 and R5 is a linker group, which covalently links the structure of formula (I) to the polymer backbone.

44. A method for preparing a lithium-ion selective resin by grafting reaction, the lithium-ion selective resin comprising a polymer backbone and at least one 2-hydroxybenzophenone or 2-hydroxybenzaldehyde functional group, the lithium-ion selective resin comprising a structure selected from formula (II) to (V): Equation (II), Formula (III) Formula (IV), and Formula (V), in, R1 is hydrogen, methyl, or phenyl. All of R2 to R4 are H, or one of R2 to R4 is a nitro group and the rest are all H. The polymer backbone is styrene-divinylbenzene copolymer, polyvinyl chloride, polyphenylene ether, polyetheretherketone, acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene propylene rubber-styrene-acrylonitrile copolymer, acrylonitrile-butyl acrylate-styrene copolymer, acrylonitrile-vinyl chloride-styrene copolymer, methyl acrylate-butadiene-styrene copolymer, or methyl methacrylate-butadiene-styrene copolymer, or styrene-butene copolymer. The polymer backbone is a polymer capable of halomethylation or halogenation, and the degree of crosslinking of the polymer backbone is 0–7 wt.%, with a grafting amount of 0.01–5 mmol / g resin. The lithium-ion selective resin further contains covalently bonded neutral chelating functional groups, wherein the neutral chelating functional groups are ester, phosphine oxide, or crown ether functional groups, and the grafting amount of the neutral chelating functional groups is 0–3 mmol / g resin. The method includes: using a halogenated polymer matrix and a lithium chelating functional monomer as raw materials, and employing an etherification grafting reaction to covalently link the lithium chelating functional monomer to the polymer matrix, thereby forming lithium ion selective resin balls or particles.

45. The method of claim 44, wherein the amount of neutral chelating functional group grafted is 0.1 to 0.5 mmol / g resin.

46. ​​The method of claim 44, wherein the etherification grafting reaction comprises: using at least one of acetone, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide as a solvent; using at least one of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate as a base; the molar ratio of lithium chelating functional monomer to halogen in the polymer matrix is ​​0.2–1.2; the molar ratio of the base to the lithium chelating functional monomer is 0.2–1.2; the amount of solvent used is 2–20 times the mass of the polymer matrix; the grafting reaction temperature is 40–120°C; and the reaction time is 2–72 h.

47. The method of claim 44, wherein the polymer matrix is ​​a spherical chloromethylated styrene-divinylbenzene copolymer.

48. The method of claim 47, wherein the spherical chloromethylated styrene-divinylbenzene copolymer further contains sulfonic acid groups, phosphonic acid groups, or carboxylic acid groups.

49. The method of claim 47, wherein the spherical chloromethylated styrene-divinylbenzene copolymer has a chlorine content of 5 to 30 wt%.

50. The method of any one of claims 47 to 49, wherein the degree of crosslinking of the spherical chloromethylated styrene-divinylbenzene copolymer is 0 to 5%.

51. The method of claim 50, wherein the degree of crosslinking of the spherical chloromethylated styrene-divinylbenzene copolymer is 0.5 to 2%.

52. The method according to any one of claims 47 to 49, wherein, The spherical chloromethylated styrene-divinylbenzene copolymer is prepared by chloromethylation of styrene-divinylbenzene copolymer white spheres.

53. The method of claim 47, wherein, In the etherification grafting reaction, tetrabutylammonium chloride, tetrabutylammonium bromide, or tetrabutylammonium iodide is added as a phase transfer catalyst.

54. The method of claim 47, wherein, Potassium iodide is added as a catalyst in the etherification grafting reaction.

55. A method for preparing a lithium-ion selective resin via copolymerization, the method comprising: Lithium-ion selective resin balls or particles are prepared by copolymerizing 4-(4-vinylbenzoxy)-2-hydroxybenzophenone with styrene and optionally divinylbenzene.

56. The method of claim 55, wherein the lithium-ion selective resin balls or particles are prepared by suspension polymerization.

57. The method of claim 56, wherein the suspension polymerization comprises mixing 4-(4-vinylbenzoxy)-2-hydroxybenzophenone with liquid styrene, optionally divinylbenzene and an initiator, and then, under heating conditions, adding the mixture dropwise to an aqueous solution containing salt and a dispersing agent, reacting under vigorous stirring to obtain lithium-ion selective resin balls or particles.

58. The method of claim 55, wherein the molar ratio of styrene to 4-(4-vinylbenzoxy)-2-hydroxybenzophenone is 0.2 to 3.

59. The method of claim 55, wherein the divinylbenzene is 0 to 7% of the total weight of styrene plus 4-(4-vinylbenzoxy)-2-hydroxybenzophenone.

60. The method of claim 55, wherein the salt used is sodium chloride.

61. The method of claim 55, wherein the reinforcing dispersant used is polyvinyl alcohol.

62. The method of any one of claims 55 to 61, further comprising adding 4-vinylbenzenesulfonic acid or sodium 4-vinylbenzenesulfonate, (4-vinylbenzyl)trimethylammonium chloride or 4-vinylbenzyl alcohol copolymerized with 4-(4-vinylbenzoxy)-2-hydroxybenzophenone, styrene and divinylbenzene.

63. The method of claim 62, wherein the amount of 4-vinylbenzenesulfonic acid or sodium 4-vinylbenzenesulfonate, (4-vinylbenzyl)trimethylammonium chloride or 4-vinylbenzyl alcohol added is 0 to 3 mmol / g resin.

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