Lithium extraction resin structure, preparation, and use

Abstract

Disclosed are a lithium ion selective resin containing alkoxy grafted 2-hydroxybenzophenone (or aldehyde) functional groups, a preparation method therefor, and the use thereof. The lithium ion selective resin of the present disclosure has a high lithium-sodium separation factor and very strong chemical structural stability over a wide pH range.

Description

Structure, preparation and application of lithium extraction resin

[0001] This application claims priority to Chinese Patent Application No. 202311427366.2 filed on October 31, 2023, and the contents of the above-mentioned Chinese patent application disclosure are hereby incorporated by reference in their entirety as a part of this application. Technical Field

[0002] The present invention relates to the field of lithium extraction materials, and in particular to the structure, preparation, and application of lithium extraction resins. More specifically, the present 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 Art

[0003] The rapid development of electric vehicles has driven an increasing demand for lithium-ion batteries. As an irreplaceable chemical element essential for the production of lithium-ion batteries, lithium is becoming a strategic resource in global competition. Efficient lithium extraction from ores and brines is attracting widespread attention. The development of any type of lithium ore inevitably involves extracting lithium from aqueous solutions containing alkali and alkaline earth metals. Therefore, developing separation materials with exceptional selectivity for lithium is a key priority for efficient lithium extraction.

[0004] The main methods for extracting lithium salts from lithium-containing aqueous solutions include precipitation, adsorption, ion exchange, electrodialysis membrane, nanofiltration membrane, and solvent extraction. Among them, adsorption and membrane methods are widely used due to their advantages such as strong selectivity, simple process and equipment, continuous operation, and easy automatic control. Currently, most lithium adsorbents used are inorganic adsorbents, including aluminum hydroxide or lithium aluminum double hydroxide-based aluminum lithium adsorbents, manganese dioxide or lithium manganate-based manganese series lithium adsorbents, titanate or lithium titanate-based titanium lithium adsorbents, or manganese titanium lithium adsorbents. In addition, electrosorption or rocking chair battery lithium extraction systems containing the above-mentioned inorganic lithium adsorbent materials have also shown excellent application prospects. However, when the above-mentioned inorganic materials are used to extract lithium from lithium-containing aqueous solutions, they inevitably undergo processes such as hydration, swelling, and dissolution, resulting in adsorbent dissolution or structural failure, shortening the energy efficiency and service life of the material.

[0005] Ion exchange resins with organic polymer structures have better mechanical properties, durability and acid resistance than inorganic adsorbents. However, to date, there are only a few disclosures of pure organic polymer ion exchange resins with specific selectivity for lithium ions. Patent CN108421539 discloses an organic resin for separating lithium and sodium, which utilizes single exchange groups such as sulfonic acid, phosphoric acid, carboxylic acid, or aminodicarboxylic acid chelating groups to achieve selective separation of lithium. However, due to the small lithium-sodium separation factor, it requires complex ion exchange processes and equipment, and usually requires sodium washing with a lithium-containing solution, resulting in a relatively complicated application process. Patents CN113423499 and CN102786616 disclose organic polymer lithium extraction materials grafted with crown ethers, which utilize the crown 4 structure to achieve specific selection for lithium, with a lithium-sodium separation factor close to 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 tetrahydroxyethyl methacrylate chelated lithium extraction resin prepared by ion imprinting [Ventura et al., Selective Recovery of Lithium from Brines, PROCEEDINGS, 43rd Workshop on Geothermal Reservoir Engineering]. However, when the sodium-to-lithium ratio approaches 20, the lithium-sodium separation factor of this resin is only 3.5.

[0006] Therefore, there is still a need to develop a reagent and method that can efficiently separate lithium from alkali metals and alkaline earth metals.

[0007] Summary of the Invention

[0008] To address the problem of efficient separation of lithium from alkali metals and alkaline earth metals, the inventors, through extensive experimental research, discovered that 2-hydroxybenzophenone (or aldehyde) functional groups have a 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. They have also developed ion exchange resin materials containing alkoxy-grafted 2-hydroxybenzophenone (or aldehyde) functional groups. The disclosed resins exhibit strong chemical structural stability and a high lithium-sodium separation factor over a wide pH range.

[0009] A first aspect of the present disclosure provides a lithium ion selective resin material comprising at least one 2-hydroxybenzophenone (or aldehyde) functional group having a structure of formula (I), wherein:

[0010] R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is by a group selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, halogen and phenyl;

[0011] R2, R3, R4 and R5 are each independently hydrogen, halogen, nitro, benzyloxy, C 1-4 Alkyl, C 1- 4 alkoxy groups or linking groups, provided that at least one of R2, R3, R4 and R5 is a linking group, which connects the structure of formula (I) to the polymer backbone through a covalent bond.

[0012] A second aspect of the present disclosure provides a method for extracting lithium, comprising:

[0013] 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.

[0014] The third aspect of the present disclosure provides a method for preparing a lithium ion selective resin by a grafting reaction, comprising: using a halogenated polymer matrix and a lithium chelating functional monomer as raw materials, and using an ether-forming grafting reaction to covalently connect the lithium chelating functional monomer to the polymer matrix to form lithium ion selective resin balls or particles.

[0015] The fourth aspect of the present disclosure provides a method for preparing a lithium ion selective resin by copolymerization, comprising: using a lithium chelating functional monomer bonded to 4-vinylbenzyl ether as a raw material, copolymerizing with 4-vinylstyrene and divinylbenzene to prepare lithium ion selective resin beads or particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present invention, rather than limiting the present invention.

[0017] FIG1 shows the dynamic lithium extraction performance test of the lithium extraction resin 8P3 prepared in Example 11 for low sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines.

[0018] FIG2 shows the dynamic lithium extraction performance test of the lithium extraction resin 8P3 prepared in Example 11 for high sodium / lithium, potassium / lithium, rubidium / lithium and cesium / lithium ratio brines.

[0019] FIG3 shows the cycle performance of the lithium extraction resin of Example 24.

[0020] FIG4 shows an infrared spectrum of the lithium-extracting resin of Example 25.

[0021] FIG5 shows a micrograph of the backbone resin of Example 26 before grafting.

[0022] FIG6 shows a micrograph of the grafted lithium-extracted resin of Example 26. DETAILED DESCRIPTION

[0023] All publications and patents mentioned in this disclosure are hereby incorporated into the present invention in their entirety by reference. If the purposes or terms used in any publications and patents incorporated by reference conflict with the purposes or terms used in the present invention, then the purposes and terms of the present invention prevail.

[0024] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0025] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly used in the art to which the claimed subject matter belongs. If there are multiple definitions for a term, the definition herein shall prevail.

[0026] Except in the working examples or otherwise indicated, all numbers stating quantitative qualities such as dosage in the specification and claims should be understood to be modified by the term "about" in all cases. It should also be understood that any numerical range recited in this application is intended to include all subranges within the range and any combination of the respective endpoints of the range or subrange, for example, an integer from 1 to 20 includes 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 and 20, and also includes subranges 1-3, 1-4, 1-10, 2-4, 2-10, etc.

[0027] As used in this disclosure, words such as "include," "comprising," or "including" mean that the elements preceding the word include the elements listed after the word and their equivalents, without excluding unlisted elements. The terms "comprising" or "including" as used herein may be open, semi-closed, or closed. In other words, the terms also include "consisting essentially of" or "consisting of."

[0028] The term "optionally" in this disclosure means that the described circumstances may or may not occur.

[0029] The present invention may be implemented in other specific forms without departing from the essential attributes of the present invention. It should be understood that, without conflict, any and all embodiments of the present invention may be combined with the technical features of any other embodiment or multiple other embodiments to produce additional embodiments. The present invention includes additional embodiments resulting from such combinations.

[0030] The description of the present disclosure should be interpreted in accordance with the laws and principles of chemical bonding.In some cases, it may be possible to remove a hydrogen atom in order to accommodate a substituent at a given position.

[0031] The term "alkyl" in this disclosure refers to branched and straight-chain monovalent hydrocarbon groups having n carbon atoms and 2n+1 hydrogen atoms. C1-C4 alkyl refers to straight-chain or branched saturated monovalent hydrocarbon groups having 1 to 4 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl. In one embodiment, the C1-C4 alkyl group is preferably straight-chain, i.e., methyl, ethyl, propyl, and n-butyl.

[0032] The term "alkoxy" in this disclosure refers to an alkyl group as defined above connected to the parent structure via an oxygen radical. Typical alkyl groups include, but are not limited to, methoxy, ethoxy, propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, isobutoxy, tert-butoxy, pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, heptyloxy, octyloxy, 2-ethylhexyloxy, nonyloxy, decyloxy, dodecyloxy, hexadecyloxy, etc.

[0033] The term "nitro" in this disclosure refers to a -NO2 group.

[0034] The term "benzyloxy" in the present disclosure refers to a monovalent group PhCH2O- remaining after benzyl alcohol loses a hydrogen atom from the hydroxyl group.

[0035] The term "halo" or "halogen" in this disclosure refers to fluorine, chlorine, bromine or iodine. In some embodiments, "halo" or "halogen" is chlorine or bromine. In other embodiments, "halo" or "halogen" is fluorine.

[0036] The present disclosure provides a lithium ion selective resin comprising at least one 2-hydroxybenzophenone (or aldehyde) functional group having a structure of formula (I), wherein:

[0037] R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is by a group selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, halogen and phenyl;

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

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

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

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

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

[0043] In one embodiment, the R1 group in the structures represented by formulas (II) to (V) is hydrogen, methyl or benzene, and R2 to R4 are all H.

[0044] In another embodiment, the R1 group in the structures represented by formulas (II) to (V) is hydrogen, methyl or benzene, one of R2 to R4 is nitro, and the rest are H.

[0045] Preferably, the polymer backbone is a polymer capable of being halomethylated or halogenated.

[0046] For example, 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 (meth)acrylate-butadiene-styrene copolymer, or styrene-butylene copolymer.

[0047] In one embodiment, the polymer backbone of the lithium ion selective resin has a crosslinking degree of 0 to 7 wt.%.

[0048] 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 of the polymer backbone is about 0.1 to 1.5 mm, about 0.2 to 1.2 mm, or about 0.5 to 1.5 mm.

[0049] In one embodiment, the polymer backbone of the lithium ion selective resin is particles. Preferably, the polymer backbone particles have a particle size of about 12 to 160 mesh, for example, about 15-150 mesh, about 20-100 mesh, or about 50-100 mesh.

[0050] In one embodiment, the 2-hydroxybenzophenone (or aldehyde) type functional group having the structure of formula (I) is derived from a lithium chelating functional monomer selected from the group consisting of 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxypropiophenone, 2,4-dihydroxybutyrophenone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxypropiophenone, 2,6-dihydroxybutyrophenone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-propiophenone, 2,4-dihydroxy-5-nitro-butyrophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzaldehyde , 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-propiophenone, 2,4-dihydroxy-3-nitro-butyrophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-propiophenone, 2,6-dihydroxy-3-nitro-butyrophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-propiophenone, 2,6-dihydroxy-5-nitro-butyrophenone, 2,6-dihydroxy-5-nitro-benzophenone, a mixture of one or more of the following, or a halogenated derivative of these substances. For example, the lithium chelating functional monomer and the polymer backbone are bonded to form an ether bond to graft a 2-hydroxybenzophenone (or aldehyde) functional group having the structure of formula (I) onto the resin.

[0051] In one embodiment, the grafting amount of the lithium chelating functional monomer is about 0.01 to 5 mmol / g resin, such as about 0.1 to 1 mmol / g resin, about 0.5 to 3 mmol / g resin, or about 1.5 to 4.5 mmol / g resin.

[0052] In one embodiment, the lithium ion selective resin material further comprises a modifying group for improving hydrophilicity. Preferably, the modifying group for improving hydrophilicity comprises one or more of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phenolic hydroxyl group, an alcoholic hydroxyl group, an iminodiacetic acid group, a primary amine group, a secondary amine group, and a quaternary ammonium group.

[0053] For example, 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.

[0054] In one embodiment, the grafted amount of the hydrophilicity-improving modifying group is about 0 to 3 mmol / g resin, such as about 0.1 to 1 mmol / g resin, or about 0.5 to 2.5 mmol / g resin.

[0055] Preferably, the lithium ion selective resin further contains a cation exchange group or an anion exchange group.

[0056] In one embodiment, the lithium ion-selective resin further comprises a covalently bonded neutral chelating functional group. Preferably, the neutral chelating functional group is a ketone, an ester, a phosphine oxide, or a crown ether. For example, the neutral chelating functional group is ethyl benzoate, (2-hydroxybenzyl)diphenylphosphine oxide, 2,5-dihydroxyphenyldiphenylphosphine oxide, benzo-12-crown-4, and / or dibenzo-14-crown-4.

[0057] In one embodiment, the grafted amount of the neutral chelating functional group is about 0 to 3 mmol / g resin, for example, about 0.1 to 0.5 mmol / g resin or about 0.5 to 2.5 mmol / g resin.

[0058] Preferably, the lithium ion selective resin has a lithium saturation exchange capacity of about 0.05 to 1 mmol / g resin, for example, about 0.1 to 0.9 mmol / g resin.

[0059] The present disclosure also provides a method for extracting lithium, comprising contacting the lithium ion selective resin with a lithium-containing solution, and then separating the lithium ion selective resin.

[0060] The lithium ion selective resin can be used to extract lithium from lithium-containing aqueous solutions, such as neutral or alkaline salt lake brine with low magnesium and calcium content, geothermal brine, or lithium carbonate or lithium phosphate precipitation mother liquor.

[0061] For example, the pH of an aqueous solution containing lithium ions is about 5 to 13, preferably about 8 to 12.5. For alkaline natural brine, the brine can be directly contacted with a lithium ion-selective resin to load the lithium ions in the brine onto the lithium ion-selective resin. For lithium-containing aqueous solutions with a pH < 7, the pH and alkalinity can be adjusted to about 8 to 13 by adding alkali metal or ammonium hydroxides, carbonates, phosphates, or borates.

[0062] The method for extracting lithium may further include regenerating the lithium-ion-selective resin after contact with the lithium-containing solution. For example, a stripping agent may be used to react with the lithium-ion-selective resin loaded with lithium ions, thereby allowing the lithium ions to enter the stripping agent and re-enabling the lithium-ion-selective resin to extract lithium from the lithium-containing aqueous solution. The stripping agent is an aqueous acid solution, preferably one or more of carbonic acid, sulfuric acid, sulfurous acid, hydrochloric acid, nitric acid, and phosphoric acid.

[0063] The present disclosure also provides a method for preparing a lithium ion selective resin by a grafting reaction, comprising: using a halogenated polymer matrix and a lithium chelating functional monomer as raw materials, and using an ether-forming grafting reaction to covalently connect the lithium chelating functional monomer to the polymer matrix to form lithium ion selective resin balls or particles.

[0064] In one embodiment, the ether-forming grafting reaction is: using at least one of acetone, acetonitrile, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide as a solvent, and using 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 ​​about 0.2 to 1.2, for example, about 0.5 to 1.0, the molar ratio of the base to the lithium chelating functional monomer is about 0.2 to 1.2, for example, about 0.5 to 1.0, the amount of the solvent is about 2 to 20 times the mass of the polymer matrix, for example, about 2 to 5 times, the grafting reaction temperature is about 40 to 120° C., for example, about 40 to 90° C., and the reaction time is about 2 to 72 hours, for example, about 2-8 hours.

[0065] Preferably, the method for preparing the lithium ion selective resin further comprises recovering the solvent by filtering after the grafting reaction is completed, and the recovered solvent is recycled.

[0066] For example, the polymer matrix is ​​a spherical chloromethylated styrene-divinylbenzene copolymer. Preferably, the spherical chloromethylated styrene-divinylbenzene copolymer further contains a sulfonic acid group, a phosphonic acid group or a carboxylic acid group.

[0067] In one embodiment, the spherical chloromethylated styrene-divinylbenzene copolymer has a chlorine content of about 5 to 30 wt%, such as about 5 to 10 wt%.

[0068] In one embodiment, the spherical chloromethylated styrene-divinylbenzene copolymer has a crosslinking degree of about 0 to 5%, such as about 0.5 to 2%.

[0069] For example, the spherical chloromethylated styrene-divinylbenzene copolymer can be prepared by chloromethylating white styrene-divinylbenzene copolymer balls.

[0070] In one embodiment, tetrabutylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium iodide is added as a phase transfer catalyst in the ether-forming grafting reaction.

[0071] Preferably, potassium iodide is added as a catalyst in the ether-forming grafting reaction.

[0072] The present disclosure also provides a method for preparing a lithium-ion-selective resin by copolymerization, comprising: using a lithium-chelating functional monomer bonded to 4-vinylbenzyl ether as a raw material, and copolymerizing it with 4-vinylstyrene and optionally divinylbenzene to prepare lithium-ion-selective resin beads or particles. Here, "optional divinylbenzene" means that divinylbenzene may or may not be present.

[0073] Preferably, the copolymerization method for preparing the resin spheres or particles employs a suspension polymerization process. For example, a lithium chelating functional monomer bonded to 4-vinylbenzyl ether is mixed with liquid styrene, optionally divinylbenzene, and an initiator. The mixture is then added dropwise to an aqueous solution containing a salt, such as sodium chloride, and a dispersing agent, such as polyvinyl alcohol, under heating conditions. The mixture is reacted under vigorous stirring to obtain a spherical or granular lithium ion selective resin. The initiator may be, for example, an oil-soluble initiator such as azobisisobutyronitrile, azobisisoheptanenitrile, azobisisovaleronitrile, azobiscyclohexylcarbonitrile, dimethyl azobisisobutyrate, or benzoyl peroxide. Preferably, the molar ratio of styrene to the lithium chelating functional monomer bonded to 4-vinylbenzyl ether is approximately 0.2 to 3, for example, approximately 0.5 to 2. Preferably, the divinylbenzene constitutes approximately 0 to 7% of the total weight of the styrene and the lithium chelating functional monomer bonded to 4-vinylbenzyl ether. When the amount of divinylbenzene is 0% of the total weight of the lithium chelating functional monomers bonded with styrene and 4-vinylbenzyl ether, no divinylbenzene is added in the copolymerization reaction.

[0074] The lithium chelate functional monomer bonded with 4-vinylbenzyl ether can be prepared by reacting the lithium chelate functional monomer of the following formula (VI) with 4-vinylbenzyl chloride to generate an ether.

[0075] R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is by a group selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, halogen and phenyl;

[0076] R2, R3, R4 and R5 are each independently hydroxy, hydrogen, halogen, nitro, benzyloxy, C 1-4 Alkyl or C 1-4 Alkoxy, provided that at least one of R2, R3, R4 and R5 is hydroxy. For example, R3 or R5 is hydroxy.

[0077] Exemplary lithium chelating functional monomers of formula (VI) may include: 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxypropiophenone, 2,4-dihydroxybutyrophenone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxypropiophenone, 2,6-dihydroxybutyrophenone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-propiophenone, 2,4-dihydroxy-5-nitro-butyrophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzaldehyde, 2,4-dihydroxy- 3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-propiophenone, 2,4-dihydroxy-3-nitro-butyrophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-propiophenone, 2,6-dihydroxy-3-nitro-butyrophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-propiophenone, 2,6-dihydroxy-5-nitro-butyrophenone, and a mixture of one or more thereof.

[0078] 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 of a base such as lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate.

[0079] In one embodiment, the copolymerization reaction further comprises adding a monomer for improving the hydrophilicity of the lithium ion-selective resin to copolymerize with the lithium chelating functional monomer bonded to 4-vinylbenzyl ether, styrene, and optionally divinylbenzene. Preferably, the monomer for improving the hydrophilicity of the lithium ion-selective resin added in the copolymerization method for preparing the lithium ion-selective resin is about 0 to 3 mmol / g resin, for example, about 0.1 to 1 mmol / g resin, or about 0.5 to 2.5 mmol / g resin.

[0080] The monomer for improving the hydrophilicity of the lithium ion selective resin may contain a modifying group that improves the hydrophilicity, such as one or more of a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a phenolic hydroxyl group, an alcoholic hydroxyl group, an iminodiacetic acid group, a primary amine group, a secondary amine group, and a quaternary ammonium group.

[0081] For example, examples of the monomer for improving the hydrophilicity of the lithium ion selective resin may include 4-vinylbenzenesulfonic acid (sodium), 4-vinylbenzoic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride, or 4-vinylbenzyl alcohol.

[0082] In one embodiment, the copolymerization reaction further comprises adding 4-vinylbenzenesulfonic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride or a lithium chelating functional monomer bonded with 4-vinylbenzyl alcohol and 4-vinylbenzyl ether, styrene and divinylbenzene to improve the hydrophilicity of the lithium ion selective resin.

[0083] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention more clear, the specific embodiments of the present invention are clearly and completely described below. The embodiments described below are exemplary and are only used to explain the present invention, and are not to be understood as limiting the present invention. Based on the described embodiments of the present invention, all other implementations obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0084] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all commercially available conventional products.

[0085] Unless otherwise defined, technical or scientific terms used in the following embodiments should have the same general meanings as those generally understood by persons having ordinary skills in the field to which the present invention belongs.

[0086] Example 1

[0087] 2,4-dihydroxybenzophenone was grafted onto a chloromethylated styrene-divinylbenzene copolymer intermediate as a polymer backbone: 20 g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, 0.5% divinylbenzene content, 20 wt% chlorine content) was added to a 250 mL spherical reaction bottle, and 120 mL of N,N-dimethylformamide (DMF) was added. The mixture was stirred at room temperature for 2 hours, and then 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 naturally cooled to room temperature, the DMF mother liquor was filtered off, and the resin balls were washed several times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 62 g of wet lithium extraction resin with a resin moisture content of 33 wt.%, which was recorded as lithium extraction resin 1.

[0088] Example 2

[0089] 2,4-dihydroxy-5-nitro-benzophenone was grafted onto a chloromethylated styrene-divinylbenzene copolymer intermediate as a polymer backbone: 20 g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, 0.5% divinylbenzene content, 20 wt% chlorine content) was added to a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added and the mixture was stirred 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 naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin spheres were washed several times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 69 g of wet lithium extraction resin with a water content of 34 wt%. This resin was designated as lithium extraction resin 2.

[0090] Example 3

[0091] 2,4-Dihydroxyacetophenone was grafted 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 added to a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added and the mixture was stirred 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. The mixture was heated to 90°C and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 55 g of wet lithium extraction resin with a water content of 33 wt%. This resin was designated as lithium extraction resin 3.

[0092] Example 4

[0093] 2,4-dihydroxy-5-nitro-acetophenone was grafted 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 added to a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added and the mixture was stirred 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 naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 67 g of wet lithium extraction resin with a water content of 34 wt%. This resin was designated as lithium extraction resin 4.

[0094] Example 5

[0095] 2,4-dihydroxy-5-nitro-acetophenone was grafted 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 added to a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added and the mixture was stirred 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 naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 49 g of wet lithium extraction resin with a water content of 28 wt%. This resin was designated as lithium extraction resin 5.

[0096] Example 6

[0097] 2,4-dihydroxy-5-nitro-acetophenone was grafted 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 added to a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added and the mixture was stirred 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 naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 44 g of wet lithium extraction resin with a water content of 19 wt%. This resin was designated as lithium extraction resin 6.

[0098] Example 7

[0099] 2,4-dihydroxy-5-nitro-acetophenone was grafted onto a chloromethylated styrene-divinylbenzene copolymer intermediate as the polymer backbone: 20 g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<100 mesh, 0.5% divinylbenzene content, 20 wt% chlorine content) was added to a 250 mL spherical reaction flask. 120 mL of N,N-dimethylformamide (DMF) was added and the mixture was stirred 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 naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin spheres were washed multiple times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 70 g of wet lithium extraction resin with a water content of 34 wt%. This resin was designated as lithium extraction resin 7.

[0100] Example 8

[0101] 2,4-dihydroxy-5-nitro-benzophenone was grafted onto a chloromethylated styrene-divinylbenzene copolymer intermediate as a polymer backbone: 20 g of dried spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<100 mesh, 0.5% divinylbenzene content, 20 wt% chlorine content) was added to a 250 mL spherical reaction bottle, and 120 mL of N,N-dimethylformamide (DMF) was added. The mixture was stirred at room temperature for 2 hours, and 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 naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin balls were washed several times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 70 g of wet lithium extraction resin with a water content of 34 wt%. This resin was recorded as lithium extraction resin 8.

[0102] Example 9

[0103] Hydrophilic modification of lithium-extracting resin 8: 30 g of washed and dried lithium-extracting resin 8 was placed in a 250 mL round-bottom flask, 100 mL of tetrahydrofuran was added to swell for 2 hours, and then 20 mmol each of trimethylamine hydrochloride and solid sodium hydroxide were added. The mixture was stirred at room temperature for 10 hours, and the reaction mother liquor was filtered out. The resin was washed with water several times to obtain hydrophilically modified lithium-extracting resin 8, which was recorded as lithium-extracting resin 8P1.

[0104] Example 10

[0105] Hydrophilic modification of lithium-extracting resin 8: 30 g of washed and dried lithium-extracting resin 8 was placed in a 250 mL round-bottom flask, 100 mL of tetrahydrofuran was added to swell for 2 hours, and then 20 mmol of triethanolamine was added. The mixture was stirred and reacted at 50°C for 10 hours. The reaction mother liquor was then filtered out and the resin was washed with water several times to obtain hydrophilically modified lithium-extracting resin 8, which was recorded as lithium-extracting resin 8P2.

[0106] Example 11

[0107] Neutral synergistic chelating ligand modification of lithium-extraction resin 8: 30 g of washed and dried lithium-extraction resin 8 was placed in a 250 mL round-bottom flask and swelled with 100 mL of DMF for 2 hours. Then, 40 mmol of (2-hydroxybenzyl)diphenylphosphine oxide, 50 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, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin pellets were washed multiple times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 78 g of wet lithium-extraction resin with a moisture content of 35 wt.%. This resin was designated as lithium-extraction resin 8P3.

[0108] Example 12

[0109] Neutral synergistic chelating ligand modification of lithium-extraction resin 8: 30 g of washed and dried lithium-extraction resin 8 was placed in a 250 mL round-bottom flask and swelled with 100 mL of DMF for 2 hours. Then, 30 mmol of hydroxybenzo-12-crown-4, 40 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 naturally cooled to room temperature, the DMF mother liquor was filtered, and the resin balls were washed multiple times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 59 g of wet lithium-extraction resin with a water content of 33 wt.%. This resin was designated as lithium-extraction resin 8P4.

[0110] Example 13

[0111] Preparation of chloromethylated styrene-divinylbenzene copolymer sulfonated intermediate: 200g of dry spherical chloromethylated styrene-divinylbenzene copolymer intermediate (<30 mesh, divinylbenzene content of 0.5%, chlorine content of 20wt%) was added to a 1000mL spherical reaction flask, 1000mL of dichloroethane was added, and the mixture was stirred and swollen at room temperature for 2 hours. Afterwards, it was heated to 60°C, and 50mL of 98wt% concentrated sulfuric acid was slowly added dropwise. The reaction was stirred. After 2 hours, the resin turned brown. The reaction was stopped, and the dichloroethane solvent was distilled off under reduced pressure at 60°C. The resin was washed with water several times until neutral, and 30g of 30wt.% sodium hydroxide was added to transform the resin into the sodium type. Then, the resin was dried at 70°C to obtain 280g of the sulfonated intermediate.

[0112] Example 14

[0113] 20 g of the chloromethylated styrene-divinylbenzene copolymer sulfonated intermediate prepared in Example 13 was added to a 250 mL spherical reaction flask, 120 mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at room temperature for 2 hours. 90 mmol of 2,4-dihydroxybenzophenone, 100 mmol of potassium carbonate, and 0.5 g of potassium iodide were then added, and the mixture was heated to 90° C. and stirred for 16 hours. After the reaction was completed, the mixture was naturally cooled to room temperature, the DMF mother liquor was filtered off, and the resin balls were washed several times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 62 g of wet lithium extraction resin with a resin moisture content of 33 wt.%, which was recorded as lithium extraction resin 14.

[0114] Example 15

[0115] 2,4-dihydroxybenzophenone was grafted onto polyvinyl chloride as the polymer backbone: 20g of polyvinyl chloride powder (<100 mesh, chlorine content 56-58wt%) was added to a 250mL spherical reaction bottle, 120mL of N,N-dimethylformamide (DMF) was added, and the mixture was stirred at room temperature for 2 hours to dissolve. Then, 90mmol of 2,4-dihydroxybenzophenone, 100mmol of cesium carbonate, and 0.5g 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 naturally cooled to room temperature, 500mL of water was added, and the DMF+water mixture was filtered out. The resin powder was washed with 0.1M dilute sulfuric acid several times, and then with 0.3M sodium hydroxide solution several times to obtain 42g of wet lithium extraction resin powder, which was recorded as lithium extraction resin 15.

[0116] Example 16

[0117] 2,4-dihydroxybenzophenone was grafted onto poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) as the polymer backbone: 20 g of poly (2,6-dimethyl-1,4-phenylene oxide) powder was added to a 250 mL spherical reaction bottle, 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, which was then dissolved in 150 mL of N,N-dimethylformamide (DMF). 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, the mixture was naturally cooled to room temperature, 500 mL of water was added, the DMF+water mixture was filtered out, and the resin powder was washed several times with 0.1 M dilute sulfuric acid and then with 0.3 M sodium hydroxide solution to obtain 50 g of wet lithium extraction resin powder, which was recorded as lithium extraction resin 16.

[0118] Example 17

[0119] Styrene-divinylbenzene-4-(4-vinylbenzyloxy)-2-hydroxybenzophenone suspension copolymerization: 1) Preparation of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone polymerization 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, heated to 70°C and dissolved for half an hour, then 90 mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was complete, the mixture was reacted for 7 hours, and then 500 mL of deionized water was added to precipitate a solid product, which was filtered, washed multiple times, and dried to obtain 30 g of the product for later use. 2) Take 100g of styrene and wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set aside; take 7g of divinylbenzene and wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set aside; 30g of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone is mixed with 100g of styrene and 7g of divinylbenzene after deblocking, 2.5g of benzoyl peroxide is added, and after mixing evenly, it is added dropwise to the suspension polymerization aqueous phase under strong stirring. The configuration process of the suspension polymerization aqueous phase is as follows: 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol are added to a 1000mL round-bottom flask, and the solution is stirred until a uniform solution is obtained. The reaction temperature is 80°C and the polymerization time is 8 hours. After the reaction is completed, the solution is filtered to obtain 120g of lithium-extracting resin balls, which are recorded as lithium-extracting resin 17.

[0120] Example 18

[0121] Styrene-divinylbenzene-4-(4-vinylbenzyloxy)-2-hydroxybenzophenone-4-vinylbenzenesulfonic acid suspension copolymerization: 1) Preparation of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone polymerization 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, heated to 70°C and dissolved for half an hour, then 90 mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was complete, the mixture was reacted for 7 hours, and then 500 mL of deionized water was added to precipitate a solid product, which was filtered, washed multiple times, and dried to obtain 30 g of the product for later use. 2) Take 100g of styrene and wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set aside; take 7g of divinylbenzene and wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set aside; 30g of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone is mixed with 100g of styrene after deblocking, 7g of divinylbenzene and 10g of 4-vinylbenzenesulfonic acid, 3.5g of benzoyl peroxide is added, and after mixing evenly, it is added dropwise to the suspension polymerization aqueous phase under vigorous stirring. The suspension polymerization aqueous phase is prepared as follows: 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol are added to a 1000mL round-bottom flask, and the solution is stirred until a uniform solution is obtained. The reaction temperature is 90°C and the polymerization time is 6 hours. After the reaction is completed, the solution is filtered to obtain 130g of lithium-extracting resin balls, which are recorded as lithium-extracting resin 18.

[0122] Example 19

[0123] Styrene-divinylbenzene-4-(4-vinylbenzyloxy)-2-hydroxybenzophenone-triethyl(4-vinylbenzyl)ammonium chloride suspension copolymerization: 1) Preparation of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone polymerization 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, heated to 70°C and dissolved for half an hour, then 90 mmol of 4-vinylbenzyl chloride was added dropwise. After the addition was complete, the mixture was reacted for 7 hours, and then 500 mL of deionized water was added to precipitate a solid product, which was filtered, washed multiple times, and dried to obtain 30 g of the product for later use. 2) Take 100g of styrene and wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set aside; take 7g of divinylbenzene and wash it with 10wt% sodium hydroxide aqueous solution several times to remove the inhibitor and set aside; 30g of 4-(4-vinylbenzyloxy)-2-hydroxybenzophenone is mixed with 100g of styrene after deblocking, 7g of divinylbenzene and 15g of triethyl (4-vinylbenzyl) ammonium chloride, 3.5g of benzoyl peroxide is added, and after mixing evenly, it is added dropwise to the suspension polymerization aqueous phase under vigorous stirring. The suspension polymerization aqueous phase is prepared as follows: 400mL of deionized water, 100g of sodium chloride, and 5g of polyvinyl alcohol are added to a 1000mL round-bottom flask, and the solution is stirred until a uniform solution is obtained. The reaction temperature is 90°C and the polymerization time is 6 hours. After the reaction is completed, the solution is filtered to obtain 137g of lithium-extracting resin balls, which are recorded as lithium-extracting resin 19.

[0124] Example 20

[0125] Static lithium exchange performance test of the lithium-extraction resin prepared in Examples 1 to 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) Experimental process: 5 g of wet resin was added to 20 mL of the experimental raw material brine, and the mixture was shaken at room temperature for 24 hours. The residual solution was diluted and the lithium content was determined by ion chromatography (IC), and the exchange capacity was calculated. The results are listed in Table 1 below:

[0126] Table 1: Static lithium exchange performance of lithium-extraction resins prepared in Examples 1 to 19

[0127] Example 21

[0128] The static separation performance test of lithium / sodium, lithium / potassium, lithium / rubidium and lithium / cesium of the lithium extraction resin prepared in Examples 1 to 19: 1) The experimental raw material brine is 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 + =1.477 g / L, pH=13); 2) Experimental Procedure: 5 g of wet resin was added to 20 mL of experimental raw brine, and the mixture was shaken at room temperature for 24 hours. The remaining solution was diluted and the contents of lithium, sodium, potassium, rubidium, and cesium were determined by ion chromatography (IC), and the separation factor α (A / B) was calculated. The results are listed in Table 2 below.

[0129] Table 2: Static lithium / sodium, lithium / potassium, lithium / rubidium, and lithium / cesium separation performance of the lithium extraction resins prepared in Examples 1 to 19

[0130] Example 22

[0131] 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):

[0132] 1) The raw material brine is 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 process: Take 60g of wet resin and put it into the In a 50 cm long ion exchange column, the experimental raw brine was passed through the resin column at a flow rate of 1 to 1.5 mL / min. The effluent was collected in sections and its composition was analyzed by ion chromatography (IC). The resin column was then washed with water, and the lithium was eluted with 0.1 mol / L hydrochloric acid. The resulting operating curve is shown in Figure 1. 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.

[0133] Example 23

[0134] 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):

[0135] 1) The experimental raw material brine is 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 + =2.196g / L, OH - The concentration was 0.2 mol / L); 2) Experimental procedure: The resin column described in Example 22 was used, with the experimental raw brine passing through the resin column at a flow rate of 1-1.5 mL / min. The effluent was collected in sections and its composition was determined by ion chromatography (IC). The resin column was then washed with water, and the lithium was eluted with 0.1 mol / L hydrochloric acid. The resulting operating curve is shown in FIG2 , and the system separation factors are α(Li / Na)=733.08, α(Li / K)=1281.99, α(Li / Rb)>10000, and α(Li / Cs)>10000.

[0136] Example 24. Cyclic performance of lithium extraction resin

[0137] Take 5g of lithium-extracting resin 1, add 20mL of 0.25mol / L lithium hydroxide aqueous solution (lithium concentration determined by ion chromatography is 1.73g / L), shake and react 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. The remaining liquid was then separated and 20 mL of 0.2 mol / L hydrochloric acid solution was added to elute the lithium and regenerate the resin. After 24 hours of oscillation, the eluate was separated and washed with water twice until neutral, ready for the next lithium exchange capacity measurement. This experimental process was repeated 10 times, and the lithium exchange capacity obtained for each measurement is shown in Figure 3.

[0138] Example 25. Infrared spectrum of lithium extraction resin

[0139] The infrared spectra of lithium-extracting resins 1 and 3 are shown in Figure 4. Both lithium-extracting resins are grafted products of chloromethylated styrene-divinylbenzene spherical copolymers. After grafting, the infrared vibration of the C-Cl of the chloromethyl group (ν = 670 cm -1 ) characteristics disappear, and the characteristic infrared absorption of ether bond and ketone group appears (ν=3020~3050cm -1 ;ν=1680~1700cm -1 )

[0140] Example 26. Comparison of micrographs of the backbone resin before grafting and the lithium-extracting resin after grafting

[0141] Figure 5 shows a micrograph of the styrene-divinylbenzene copolymer backbone resin spheres before grafting, and Figure 6 shows a micrograph of the lithium-extracting resin spheres after grafting the styrene-divinylbenzene copolymer backbone. Comparing Figures 5 and 6, it can be seen that the resin spheres become larger and yellow in color after grafting.

[0142] Example 27. Determination of Exchange Capacity (for Characterizing Grafting Effect)

[0143] Take 5g of lithium-extracting resin balls that have been washed and dried with filter paper, add 20mL of 0.25mol / L lithium hydroxide aqueous solution (lithium concentration is 1.73g / L), shake at room temperature for 24 hours, take the remaining solution and dilute it, and determine the lithium content by ion chromatography (IC), so as to calculate the exchange capacity of the resin: lithium exchange capacity = (Li 原始 -Li 余液 ) g / L × 20 mL / 5 g. Furthermore, the lithium-loaded resin beads were separated and washed twice with water, and then titrated with 0.2 mol / L hydrochloric acid (methyl orange as an indicator) to determine the acid consumption of the lithium-loaded resin beads, thereby calculating the exchange capacity during elution: lithium exchange capacity = hydrochloric acid titration L × 0.2 mol / L × 6.94 / 5 g.

[0144] The foregoing description is merely an exemplary embodiment of the present disclosure and is not intended to limit the scope of protection of the present disclosure. The scope of protection of the present disclosure is determined by the appended claims.

Claims

1. A lithium ion selective resin comprising at least one 2-hydroxybenzophenone (or aldehyde) functional group having a structure of formula (I), wherein: R1 is hydrogen, optionally substituted C1-C4 alkyl or optionally substituted benzene, wherein the substitution is carried out 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, C 1-4 Alkyl, C 1- 4 alkoxy or a linking group, provided that at least one of R2, R3, R4 and R5 is a linking group, which connects the structure of formula (I) to the polymer backbone through a covalent bond.

2. The lithium ion selective resin according to claim 1, wherein R1 in the structure of formula (I) is hydrogen, methyl or phenyl.

3. The lithium ion selective resin according to claim 1 or 2, wherein one of R2 to R5 in the structure of formula (I) is a linking group, and the others are all H.

4. The lithium ion selective resin according to claim 1 or 2, wherein one of R2 to R5 is a nitro group.

5. The lithium ion selective resin of claim 4, wherein except for the nitro group and the linking group, the rest of R2 to R5 are H.

6. The lithium ion selective resin according to any one of claims 1 to 5, wherein The connecting groups in R2 to R5 connected to the polymer backbone are ether bonds, so that the molecular structure containing formula (I) is grafted onto the polymer backbone.

7. The lithium ion selective resin according to any one of claims 1 to 6, which has a structure of one of formulas (II) to (V):

8. The lithium ion selective resin according to any one of claims 1 to 7, wherein the R1 group is hydrogen, methyl or benzene, and R2 to R4 are all H.

9. The lithium ion selective resin according to any one of claims 1 to 7, wherein the R1 group is hydrogen, methyl or benzene; one of R2 to R4 is a nitro group, and the others are all H.

10. The lithium ion selective resin according to any one of claims 1 to 9, wherein the polymer backbone is a polymer capable of being halomethylated or halogenated.

11. The lithium ion selective resin of any one of claims 1 to 10, wherein 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 (meth)acrylate-butadiene-styrene copolymer, or styrene-butylene copolymer.

12. The lithium ion selective resin according to any one of claims 1 to 11, wherein the crosslinking degree of the polymer backbone is 0 to 7 wt.%.

13. The lithium ion selective resin according to any one of claims 1 to 12, wherein the polymer skeleton has a gel structure or a macroporous structure.

14. The lithium ion selective resin of claim 13, wherein the polymer skeleton is spherical.

15. The lithium ion selective resin of claim 14, wherein the sphere diameter of the polymer skeleton is about 0.1 to 1.5 mm.

16. The lithium ion selective resin of any one of claims 1 to 15, wherein the 2-hydroxybenzophenone (or aldehyde) type functional group having the structure of formula (I) is derived from a lithium chelating functional monomer selected from the group consisting of 2,4-dihydroxybenzaldehyde, 2,4-dihydroxyacetophenone, 2,4-dihydroxypropiophenone, 2,4-dihydroxybutyrophenone, 2,4-dihydroxybenzophenone, 2,6-dihydroxybenzaldehyde, 2,6-dihydroxyacetophenone, 2,6-dihydroxypropiophenone, 2,6-dihydroxybutyrophenone, 2,6-dihydroxybenzophenone, 2,4-dihydroxy-5-nitro-benzaldehyde, 2,4-dihydroxy-5-nitro-acetophenone, 2,4-dihydroxy-5-nitro-propiophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-5-nitro-benzophenone, 2,4-dihydroxy-2-nitro-benzophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,4-dihydroxy-4 ... Hydroxy-3-nitro-benzaldehyde, 2,4-dihydroxy-3-nitro-acetophenone, 2,4-dihydroxy-3-nitro-propiophenone, 2,4-dihydroxy-3-nitro-butyrophenone, 2,4-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-3-nitro-benzaldehyde, 2,6-dihydroxy-3-nitro-acetophenone, 2,6-dihydroxy-3-nitro-propiophenone, 2,6-dihydroxy-3-nitro-propiophenone Hydroxy-3-nitro-butyrophenone, 2,6-dihydroxy-3-nitro-benzophenone, 2,6-dihydroxy-5-nitro-benzaldehyde, 2,6-dihydroxy-5-nitro-acetophenone, 2,6-dihydroxy-5-nitro-propiophenone, 2,6-dihydroxy-5-nitro-butyrophenone, 2,6-dihydroxy-5-nitro-benzophenone, a mixture of one or more thereof, or halogenated derivatives of these substances.

17. The lithium ion selective resin according to claim 16, wherein The grafting amount of the lithium chelating functional monomer is about 0.01 to 5 mmol / g resin.

18. The lithium ion selective resin according to any one of claims 1 to 17, further comprising a modification group for improving hydrophilicity.

19. The lithium ion selective resin of claim 18, wherein the modifying group for improving hydrophilicity comprises: One or more of 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.

20. The lithium ion selective resin of claim 18 or 19, 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.

21. The lithium ion selective resin according to any one of claims 18 to 20, wherein the grafting amount of the hydrophilicity-improving modifying group is about 0 to 3 mmol / g of resin.

22. The lithium ion selective resin according to any one of claims 1 to 21, wherein The lithium ion selective resin further contains a cation exchange group or an anion exchange group.

23. The lithium ion selective resin of any one of claims 1 to 22, further comprising a covalently bonded neutral chelating functional group.

24. The lithium ion selective resin of claim 23, wherein the neutral chelating functional group is a ketone, an ester, a phosphine oxide or a crown ether.

25. The lithium ion selective resin of claim 23 or 24, 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.

26. The lithium ion selective resin according to any one of claims 23 to 25, wherein the amount of the neutral chelating functional group grafted is about 0 to 3 mmol / g of resin.

27. The lithium ion selective resin of any one of claims 1 to 26, wherein the lithium saturation exchange capacity of the lithium ion selective resin is about 0.05 to 1 mmol / g resin.

28. A method for extracting lithium, comprising: The lithium ion selective resin according to any one of claims 1 to 27 is contacted with a lithium-containing solution, and then the lithium ion selective resin is separated.

29. The method of claim 28, further comprising: A step of regenerating the lithium ion selective resin after contacting the resin with the lithium containing solution.

30. A method for preparing a lithium ion selective resin by grafting reaction, comprising: With halogenated polymer matrix and lithium chelating functional monomer as raw materials, the lithium chelating functional monomer is connected to the polymer matrix in the form of covalent bonds through etherification grafting reaction, thereby forming lithium ion selective resin balls or particles.

31. The method of claim 30, wherein the ether-forming grafting reaction is: 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 the lithium chelating functional monomer to the halogen in the polymer matrix is ​​about 0.2 to 1.2, the molar ratio of the base to the lithium chelating functional monomer is about 0.2 to 1.2, the amount of the solvent is about 2 to 20 times the mass of the polymer matrix, the grafting reaction temperature is about 40 to 120°C, and the reaction time is about 2 to 72 hours.

32. The method of claim 30 or 31, wherein the polymer matrix is ​​a spherical chloromethylated styrene-divinylbenzene copolymer.

33. The method of claim 32, wherein the spherical chloromethylated styrene-divinylbenzene copolymer further contains a sulfonic acid group, a phosphonic acid group, or a carboxylic acid group.

34. The method of claim 32 or 33, wherein the spherical chloromethylated styrene-divinylbenzene copolymer has a chlorine content of about 5 to 30 wt%.

35. The method of any one of claims 32-34, wherein the spherical chloromethylated styrene-divinylbenzene copolymer has a crosslinking degree of about 0 to 5%.

36. The method of any one of claims 32-35, wherein The spherical chloromethylated styrene-divinylbenzene copolymer is prepared by chloromethylation reaction of white styrene-divinylbenzene copolymer spheres.

37. The method of any one of claims 30-36, wherein Tetrabutylammonium chloride, tetrabutylammonium bromide or tetrabutylammonium iodide is added as a phase transfer catalyst in the ether-forming grafting reaction.

38. The method of any one of claims 30-37, wherein Potassium iodide is added as a catalyst in the ether-forming grafting reaction.

39. A method for preparing a lithium ion selective resin by copolymerization, comprising: The lithium ion selective resin spheres or particles are prepared by copolymerizing a lithium chelating functional monomer bonded with 4-vinylbenzyl ether with 4-vinylstyrene and optionally divinylbenzene.

40. The method of claim 39, wherein the lithium ion selective resin beads or particles are prepared by suspension polymerization.

41. The method of claim 40, wherein the suspension polymerization method comprises mixing a lithium chelating functional monomer bonded to 4-vinylbenzyl ether with liquid styrene, optional divinylbenzene and an initiator, then dropping the mixture into an aqueous solution containing salt and a reinforcing dispersing aid under heating conditions, and reacting under strong stirring to obtain lithium ion selective resin beads or particles.

42. The method of any one of claims 39-41, wherein the molar ratio of styrene to 4-vinylbenzyl ether bonded lithium chelating functional monomer is about 0.2 to 3.

43. The method of claim 42, wherein the divinylbenzene is about 0 to 7% by weight of the total weight of the lithium chelating functional monomers bonded to styrene and 4-vinylbenzyl ether.

44. The method of claim 41, wherein the salt used is sodium chloride.

45. The method of claim 41, wherein the strengthening dispersing aid used is polyvinyl alcohol.

46. ​​The method of any one of claims 39-45, further comprising copolymerizing 4-vinylbenzenesulfonic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride or a lithium chelating functional monomer bonded to 4-vinylbenzyl alcohol and 4-vinylbenzyl ether, styrene and divinylbenzene.

47. The method of claim 46, wherein the amount of 4-vinylbenzenesulfonic acid (sodium), (4-vinylbenzyl)trimethylammonium chloride or 4-vinylbenzyl alcohol added is about 0 to 3 mmol / g of the resin.

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