A shaped lithium ion adsorbent material, and a method of making and use thereof

Abstract

The present application belongs to the technical field of lithium ion resource extraction. The present application provides a shaped lithium ion adsorption material, a preparation method and application thereof. The shaped lithium ion adsorption material comprises a spherical shell polymer membrane with an internal cavity. The polymer membrane has micron-sized pores communicating the internal cavity and the outside of the spherical shell, and the internal cavity is filled with lithium ion sieves. By using the polymer membrane to wrap and limit the lithium ion sieves, the lithium ion sieves are successfully granulated and shaped in the absence of a binder. The micron-sized pores can realize internal and external mass transfer of lithium ions, so that the lithium ion sieves can be deintercalated with lithium ions. The internal cavity can also provide a certain activity space, so that the lithium ion sieves can swell, thereby being more conducive to ion exchange. By limiting the polymer membrane without applying a binder between the lithium ion sieves, the active sites can be largely exposed, thereby improving the lithium extraction effect.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion resource extraction technology, and relates to a shaped lithium-ion adsorption material, its preparation method and application. Background Technology

[0002] Liquid lithium resources are generally characterized by low lithium-ion concentration, high magnesium-to-lithium ratio (in brine from salt lakes), complex composition, and numerous associated elements. Coupled with the lack of mature separation and extraction technologies, liquid lithium resources cannot yet be industrially developed and utilized on a large scale. To achieve the separation and extraction of lithium ions from liquid lithium ore, researchers have successively developed various lithium extraction methods, such as calcination impregnation, solar evaporation, co-precipitation, solvent extraction, and adsorption.

[0003] Adsorption is a relatively ideal technique for extracting lithium ions from seawater or salt lakes. It is more suitable for the separation and enrichment of ions in large-scale, high-volume liquids, and features low energy consumption, environmental friendliness, and ease of operation, thus gradually becoming the mainstream method in the field of lithium extraction. The key to the adsorbent method is the use of lithium-ion adsorbents to adsorb and extract lithium ions.

[0004] Lithium-ion sieves are special lithium-ion adsorbents with high adsorption capacity and high selectivity. Taking metal oxide lithium-ion sieves as an example, the principle is to first introduce the target extraction ion, namely lithium ions, into the metal oxide to generate a composite metal oxide. Then, without changing the crystal structure, the target ion is extracted from it, resulting in an inorganic substance with a porous structure. This substance becomes the ion sieve corresponding to the target ion. It has the tendency to accept the originally introduced target ion and form an optimal crystal structure. Therefore, even in an environment where multiple ions exist, it still has the screening and memory function for the originally introduced target ion, hence it is also called an ion memory material.

[0005] Currently, lithium-ion sieve materials mainly include three categories: manganese-based lithium-ion sieves (LMO), titanium-based lithium-ion sieves (LTO), and aluminum-based adsorbents (LiAl-LDHs), as well as phosphate, silicate, and antimonate materials. However, regardless of the type of lithium-ion sieve, the synthesized product is mostly in powder form. In industrial applications, it suffers from poor flowability, poor water wettability, low circulation efficiency, difficulty in separating from aqueous environments, and easy loss, leading to large pressure drops and high energy consumption in column operations, thus hindering industrial applications. Existing technologies typically employ granulation, film formation, foaming, and electrospinning for reshaping, but these methods all use polymers as binders or loading materials, which can cause the active sites of the lithium-ion sieve to be covered by the binder, resulting in a decrease in lithium extraction capacity and rate.

[0006] Therefore, a new technical solution needs to be developed to avoid the impact of binder use on the forming of lithium-ion sieve materials, thereby obtaining a high-performance lithium extraction material. Summary of the Invention

[0007] In view of the problems existing in the prior art, the purpose of this invention is to provide a shaped lithium-ion adsorbent material, its preparation method, and its uses. The shaped lithium-ion adsorbent material includes a spherical polymer membrane with an internal cavity. The polymer membrane has micron-sized pores connecting the internal cavity and the outside of the spherical shell, and the internal cavity is filled with lithium-ion sieves. By using the polymer membrane to encapsulate and confine the lithium-ion sieves, the lithium-ion sieves can be successfully granulated without the presence of a binder. The micron-sized pores enable lithium-ion mass transfer between the inside and outside of the sieves, allowing for successful lithium insertion / extraction. The internal cavity provides a certain amount of space for movement, allowing the lithium-ion sieves to swell, which is more conducive to ion exchange. By confining the lithium-ion sieves with a polymer membrane instead of applying a binder between them, the active sites can be exposed to a large extent, improving the lithium extraction effect.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a molded lithium-ion adsorbent material, comprising a polymer membrane, wherein the polymer membrane is a spherical shell with an internal cavity, the polymer membrane having micron-sized pores communicating with the internal cavity and the outside of the spherical shell, and the internal cavity being filled with a lithium-ion sieve.

[0010] Inspired by the fruit mesh bags used in daily life, this invention prepares a molded lithium-ion adsorption material with a polymer membrane encapsulating a lithium-ion sieve with micron-sized pores. Because the outer polymer membrane has high hydrophilicity and provides sufficient internal cavity volume for the lithium-ion sieve, it is conducive to the exchange of aqueous solutions and ions inside and outside the polymer membrane. Furthermore, since there is no binder between the lithium-ion sieves and there is a certain amount of space for movement, the active sites are exposed to a large extent, thereby improving the lithium extraction effect.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following technical solutions.

[0012] As a preferred technical solution of the present invention, the pore size of the micron-sized pores is 0.5 to 10 μm, such as 0.5 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0013] Preferably, the pore size of the micron-sized pores is smaller than the particle size of the lithium ion sieve to prevent the lithium ions from escaping from the micron-sized pores; however, if the pore size of the micron-sized pores is too small, it will be detrimental to water exchange and ion diffusion.

[0014] Preferably, the particle size of the lithium ion sieve is 10 to 20 μm, such as 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm, 18 μm, 19 μm or 20 μm, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0015] Preferably, the volume filling degree of the lithium-ion sieve in the internal cavity is less than 100%, such as 70%, 80%, 85%, 90% or 95%, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0016] In this invention, it is preferable that a certain amount of space is still retained in the internal cavity filled with lithium ion screen, so as to provide sufficient space for the movement and swelling of lithium ion screen.

[0017] Preferably, the lithium-ion sieve is a lithium-lean lithium-ion sieve, which includes MnO2·0.5H2O, λ-MnO2, MnO2·0.3H2O, H2TiO3, or H4Ti5O. 12 At least one of them, for example, typical but non-limiting examples of combinations include combinations of MnO2·0.5H2O and λ-MnO2, combinations of MnO2·0.5H2O and MnO2·0.3H2O, combinations of MnO2·0.5H2O and H2TiO3, or combinations of H2TiO3 and H4Ti5O. 12 Combinations, etc.

[0018] Preferably, the polymer film comprises an inner polymer base film and an outer polymer reinforcing film covering the polymer base film.

[0019] In order to prevent the polymer film from being damaged during the preparation or application of the material, the present invention further coats the polymer base film with a polymer reinforcing film to increase the thickness and strength, thereby improving the stability and lifespan of the material.

[0020] In a second aspect, the present invention provides a method for preparing the molded lithium-ion adsorbent material described in the first aspect, the method comprising:

[0021] A mixed photoinitiator and thickener were prepared as an oil-phase solution.

[0022] A water-soluble inorganic salt, a reactive emulsifier, and a lithium ion sieve are mixed to prepare an aqueous solution.

[0023] The aqueous solution is dropped into the oil phase solution, and a photoinitiated reaction is carried out to form a polymer-based film that encapsulates the lithium-ion sieve suspension, thus obtaining spheres.

[0024] The spheres are washed to remove the water-soluble inorganic salts, and then dried to obtain a shaped lithium-ion adsorbent material.

[0025] The purpose of using water-soluble inorganic salts in this invention is to increase the density of the aqueous solution, allowing the water in the aqueous solution to maintain a similar settling velocity to the lithium-ion sieve. This controls the lithium-ion sieve to remain within the falling water droplets, thus simultaneously encapsulating both the water and the lithium-ion sieve within the sphere, achieving the effect of encapsulating the lithium-ion sieve suspension. In this way, after subsequent washing and dehydration, an internal cavity is formed, and the lithium-ion sieve remains within the formed internal cavity. If the aqueous solution is poured into an oil solution, phase separation may occur, causing the lithium-ion sieve to settle to the bottom and failing to form an effective encapsulation. Therefore, this invention uses a dripping method, allowing the aqueous solution to be encapsulated naturally as it falls under gravity, forming the encapsulated sphere.

[0026] As a preferred technical solution of the present invention, the preparation method further includes casting the sphere to strengthen it, forming a polymer reinforcing film and wrapping the polymer base film to obtain a reinforced sphere.

[0027] In order to avoid the polymer base film from breaking or being damaged during subsequent synthesis and product application, the present invention preferably first performs casting reinforcement to form a polymer reinforced film. The polymer reinforced film and the polymer base film together form a thicker spherical shell to obtain better mechanical strength.

[0028] Preferably, the casting strengthening method includes immersing the sphere in a sulfonated polyethersulfone casting solution and stirring for 0.5 to 2 hours, such as 0.5 hours, 0.8 hours, 1 hour, 1.2 hours, 1.4 hours, 1.6 hours, 1.8 hours, or 2 hours, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0029] The polymer-based membrane of this invention, after being wrapped with a porous material, resembles a "mesh bag." The size of the pores is determined by the degree of polymerization of the base membrane. In this way, the present invention preferably immerses the spheres in a sulfonated polyethersulfone casting solution immediately after obtaining them. This facilitates the formation of a large "mesh bag" in the sulfonated polyethersulfone casting. The superposition of the pores of the polymer base membrane and the polymer reinforcement membrane can reduce the pore size and form specific micron-sized pores. Moreover, immediate casting reinforcement helps to avoid premature water exudation that would cause the internal cavity to shrink, thereby obtaining a larger internal cavity space after washing to remove water-soluble inorganic salts and drying.

[0030] Preferably, the mass concentration of sulfonated polyethersulfone in the sulfonated polyethersulfone casting solution is 25% to 35%, such as 25%, 27%, 29%, 31%, 33%, or 35%, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0031] Preferably, the solvent in the sulfonated polyethersulfone casting solution includes at least one of N,N-dimethylformamide (DMF), dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), or tetrahydrofuran (THF), such as a combination of DMF and DMAC, a combination of DMF and NMP, a combination of DMF and THF, a combination of DMAC and NMP, a combination of DMAC and THF, or a combination of NMP and THF.

[0032] Preferably, the mass ratio of the sphere to the sulfonated polyethersulfone casting solution is 1:(40-60), for example, 1:40, 1:42, 1:44, 1:46, 1:48, 1:50, 1:52, 1:54, 1:56, 1:58 or 1:60, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0033] As a preferred embodiment of the present invention, the preparation method further includes washing the reinforced spheres to remove the water-soluble inorganic salts.

[0034] In this invention, the casting strengthening is performed first, and then the resulting strengthened spheres are washed to remove the water-soluble inorganic salts, in order to prevent cavity shrinkage caused by washing to remove the water-soluble inorganic salts first.

[0035] Preferably, the washing method includes soaking in water for 24 to 72 hours, such as 24 hours, 36 hours, 48 ​​hours, 60 hours or 72 hours, and changing the water every 4 to 16 hours, such as 4 hours, 8 hours, 12 hours or 16 hours, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0036] Preferably, when the lithium ion sieve is a lithium-rich lithium ion sieve, the preparation method further includes performing a delithiation treatment before drying and dehydration.

[0037] Preferably, the method for delithiation includes acid washing.

[0038] In the preparation method of this invention, when the lithium-ion sieve used to prepare the aqueous solution is a lithium-rich lithium-ion sieve, it should be converted into a delithiated lithium-ion sieve before lithium intercalation or adsorption can be performed. Therefore, an acid washing and delithiation step should be added after obtaining the spheres and before drying and dehydrating to obtain the shaped lithium-ion adsorbent material. Preferably, the acid washing and delithiation step is performed after the casting strengthening and washing to remove water-soluble inorganic salts. This is because prioritizing casting strengthening can enhance the strength of the polymer film and prevent damage to the polymer base film caused by subsequent operations. Under the strengthening of the polymer-reinforced film, prioritizing washing to remove water-soluble inorganic salts ensures a sufficiently large internal cavity. Of course, considering the water solubility of the water-soluble inorganic salts described in this invention, directly performing acid washing and delithiation on the obtained spheres or immediately after casting strengthening can achieve simultaneous removal of water-soluble inorganic salts and lithium-ion sieve delithiation to a certain extent, but may affect the properties and lithium extraction performance of the final shaped lithium-ion adsorbent material.

[0039] Preferably, the pickling solution includes hydrochloric acid with a concentration of 0.1 to 0.5 mol / L, such as 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, or 0.5 mol / L, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0040] Preferably, the solid-liquid ratio of the pickling feed is (0.5-1.5) g:100 mL, such as 0.5 g:100 mL, 0.8 g:100 mL, 1 g:100 mL or 1.5 g:100 mL, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0041] Preferably, the pickling time is 12 to 36 hours, such as 12 hours, 16 hours, 20 hours, 24 hours, 28 hours, 32 hours or 36 hours, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0042] Preferably, the lithium-rich lithium-ion sieve includes LiMn2O4 and Li 1.5 Mn2O4, Li 1.33 Mn 1.67 O4, Li 1.6 Mn 1.6 O4, Li2TiO3 or Li4Ti5O 12 At least one of them, for example typical but non-limiting examples of combinations include LiMn2O4 and Li 1.5 Combinations of Mn2O4, LiMn2O4 and Li 1.33 Mn 1.67 Combinations of O4, LiMn2O4 and Li1.6 Mn 1.6 A combination of O4 or Li2TiO3 and Li4Ti5O 12 The combination of .

[0043] As a preferred embodiment of the present invention, the photoinitiator includes at least one of benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenylacetone, or 1-hydroxycyclohexylphenyl ketone. Typical but non-limiting examples of combinations include combinations of benzoin dimethyl ether and 2-hydroxy-2-methyl-1-phenylacetone, combinations of benzoin dimethyl ether and 1-hydroxycyclohexylphenyl ketone, or combinations of 2-hydroxy-2-methyl-1-phenylacetone and 1-hydroxycyclohexylphenyl ketone.

[0044] Preferably, the thickener comprises polyurethane and / or nano-silica.

[0045] Preferably, the oil phase solvent in the oil phase solution has a lower density than water and is immiscible with water.

[0046] Preferably, the oil phase solvent includes at least one of diethyl ether, cyclohexane, n-hexane, cyclopentane, pentane, n-heptane, isooctane, or ethyl acetate. Typical but non-limiting examples of combinations include combinations of diethyl ether and cyclohexane, diethyl ether and n-hexane, diethyl ether and cyclopentane, diethyl ether and pentane, diethyl ether and n-heptane, diethyl ether and isooctane, diethyl ether and ethyl acetate, cyclohexane and n-hexane, cyclopentane and n-pentane, or n-heptane and ethyl acetate, etc.

[0047] Preferably, in the oil phase solution, the ratio of photoinitiator, thickener and oil phase solvent is 4g:(1-5)g:100mL, for example 4g:1g:100mL, 4g:1.5g:100mL, 4g:2g:100mL, 4g:2.5g:100mL, 4g:3g:100mL, 4g:3.5g:100mL, 4g:4g:100mL, 4g:4.5g:100mL or 4g:5g:100mL, etc., but is not limited to the listed values, and other unlisted values ​​within the above range are also applicable.

[0048] Preferably, the viscosity of the oil phase solution is 1000 to 3000 mPa·s, such as 1000 mPa·s, 1500 Pa·s, 2000 Pa·s, 2500 Pa·s or 3000 Pa·s, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0049] As a preferred technical solution of the present invention, the method of adding the aqueous solution to the oil phase solution includes placing the oil phase solution in a columnar reactor such that the liquid level of the oil phase solution is ≥25cm, for example, 25cm, 30cm, 50cm, 80cm or 100cm, and then adding the aqueous solution to the oil phase solution; however, it is not limited to the listed values, and other unlisted values ​​within the above range are also applicable.

[0050] This invention utilizes an oil phase with high viscosity and lower density than water, allowing aqueous droplets loaded with lithium-ion sieves and reactive emulsifiers to slowly settle to the bottom under gravity. During the settling process, the reactive emulsifier spontaneously migrates to the oil-water interface due to hydrophilic and hydrophobic interactions, and polymerizes under ultraviolet light to form a polymer film, thereby forming water spheres that encapsulate the lithium-ion sieve suspension. Based on experience, setting the height of the oil phase surface to be greater than 25 cm is beneficial for the complete formation of the spheres. Those skilled in the art can reasonably adjust the height of the oil phase surface with the goal of generating spheres.

[0051] Preferably, the method for carrying out the photoinitiation reaction includes irradiating the oil phase solution with an ultraviolet lamp when the aqueous phase solution is added dropwise to the oil phase solution to carry out the photoinitiation reaction.

[0052] Preferably, after the photoinitiation reaction is completed, the sphere is rinsed at least five times with an aqueous solution of sodium dodecyl sulfate and water, each with a mass concentration of 0.5% to 1.5%, for example, 0.5%, 0.8%, 1%, 1.3%, or 1.5%, but not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0053] Preferably, the water-soluble inorganic salt includes at least one of a water-soluble lithium salt, a water-soluble sodium salt, or a water-soluble potassium salt. Typical but non-limiting examples of combinations include combinations of water-soluble lithium salt and water-soluble sodium salt, combinations of water-soluble lithium salt and water-soluble potassium salt, or combinations of water-soluble sodium salt and water-soluble potassium salt.

[0054] Preferably, the mass ratio of the reactive emulsifier, water-soluble inorganic salt, and lithium-ion sieve is (0.1–0.3):(2–4):1, for example, 0.1:2:1, 0.15:2:1, 0.2:2:1, 0.25:2:1, 0.3:2:1, 0.1:2.5:1, 0.15:2.5:1, 0.2:2.5:1, 0.25:2.5:1, 0.3:2.5:1, 0.1:3:1, 0.15 The values ​​are 3:1, 0.2:3:1, 0.25:3:1, 0.3:3:1, 0.1:3.5:1, 0.15:3.5:1, 0.2:3.5:1, 0.25:3.5:1, 0.3:3.5:1, 0.1:4:1, 0.15:4:1, 0.2:4:1, 0.25:4:1, or 0.3:4:1, etc., but are not limited to the listed values. Other unlisted values ​​within the above range also apply.

[0055] In this invention, insufficient use of the reactive emulsifier will result in failure to form.

[0056] Preferably, the concentration of the water-soluble inorganic salt in the aqueous solution is 20 to 40 g / L, such as 20 g / L, 25 g / L, 30 g / L, 35 g / L or 40 g / L, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0057] As a preferred embodiment of the present invention, the reactive emulsifier includes a bifunctional reactive emulsifier and a monofunctional reactive emulsifier.

[0058] Preferably, the general chemical formula of the bifunctional reactive emulsifier includes CH(CH3)=CH-COOCH2CH2(OCH2CH2). n OOC-CH = CH(CH3), where n is an integer between 0 and 4, for example, it can be 0, 1, 2, 3 and 4.

[0059] Preferably, the bifunctional reactive emulsifier includes at least one of ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, or polyethylene glycol dimethacrylate. Typical but non-limiting examples of combinations include combinations of ethylene glycol dimethacrylate and triethylene glycol dimethacrylate, combinations of polyethylene glycol dimethacrylate and ethylene glycol dimethacrylate, or combinations of triethylene glycol dimethacrylate and polyethylene glycol dimethacrylate.

[0060] Preferably, the monofunctional reactive emulsifier comprises at least one of sodium hydroxypropanesulfonate, sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, or sodium vinyl sulfonate. Typical but non-limiting examples of combinations include combinations of sodium hydroxypropanesulfonate and sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate and sodium hydroxypropanesulfonate, or sodium vinyl sulfonate and sodium hydroxypropanesulfonate, etc.

[0061] Preferably, the molar ratio of the bifunctional reactive emulsifier to the monofunctional reactive emulsifier is 1:(5-10), such as 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, but it is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0062] As a preferred technical solution of the present invention, the preparation method includes:

[0063] A photoinitiator, thickener, and oil phase solvent are mixed at a ratio of 4g:(1-5)g:100mL to prepare an oil phase solution with a viscosity of 1000-3000mPa·s; the oil phase solvent in the oil phase solution has a lower density than water and is immiscible with water;

[0064] A water-soluble inorganic salt, a reactive emulsifier, a lithium-rich sieve with a particle size of 10-20 μm, and water are mixed to prepare a suspension as an aqueous solution. The mass ratio of the reactive emulsifier, the water-soluble inorganic salt, and the lithium-rich sieve is controlled to be (0.1-0.3):(2-4):1, and the concentration of the water-soluble inorganic salt in the aqueous solution is controlled to be 20-40 g / L.

[0065] The oil phase solution is placed in a column reactor, with the liquid level of the oil phase solution ≥25cm. The oil phase solution is irradiated with an ultraviolet lamp, and then the aqueous phase solution is added dropwise to the oil phase solution. The droplets of the aqueous phase solution slowly sink to the bottom under the action of gravity and undergo a photo-initiated reaction to form a polymer base film that encapsulates the lithium-rich lithium ion sieve suspension. After filtration under normal pressure, the film is washed at least five times each with a sodium dodecyl sulfate aqueous solution and water with a mass concentration of 0.5% to 1.5% to obtain the spheres encapsulating the lithium-rich lithium ion sieve suspension.

[0066] The spheres coated with lithium-rich lithium-ion sieve suspension were immersed in a sulfonated polyethersulfone casting solution with a mass concentration of 25%–35% at a feeding mass ratio of 1:(40–60). The mixture was stirred for 0.5–2 hours to strengthen the casting film, forming a polymer-reinforced film that coated the polymer base film, resulting in reinforced spheres. After filtration under normal pressure, the reinforced spheres were dried in an oven at 60–80°C until constant weight. Then, they were soaked in water and allowed to stand for 24–72 hours, with the water changed every 4–16 hours to remove the water-soluble inorganic salts by washing. After filtration under normal pressure again, they were dried in an oven at 60–80°C until constant weight to obtain the molded material.

[0067] The molding material was added to a hydrochloric acid solution with a concentration of 0.1-0.5 mol / L at a solid-liquid ratio of (0.5-1.5) g: 100 mL. After ultrasonic degassing, the mixture was shaken in a shaking box at room temperature for 12-36 h to fully remove lithium ions. The product was then ultrasonically washed with deionized water, filtered under normal pressure, and dried in an oven at 60-80℃ to constant weight to complete the drying and dehydration process, thus obtaining the molded lithium ion adsorbent material.

[0068] Preferably, the filtration operations in the preparation method of this invention are all carried out under normal pressure to ensure that the polymer membrane is not damaged by external forces.

[0069] Preferably, the drying temperature is 60-80°C, such as 60°C, 65°C, 70°C, 75°C or 80°C, but is not limited to the listed values. Other unlisted values ​​within the above range are also applicable.

[0070] Thirdly, the present invention provides an application of the shaped lithium-ion adsorbent material described in the first aspect, the application including lithium extraction from salt lakes.

[0071] Compared with existing technical solutions, the present invention has at least the following beneficial effects:

[0072] This invention utilizes a polymer membrane with micron-sized pores to encapsulate a lithium-ion sieve to form a shaped lithium-ion adsorption material. Because the outer polymer membrane has high hydrophilicity and provides sufficient internal cavity volume for the lithium-ion sieve, the sieve can not only be fixed within the internal cavity but also swell within it, thus facilitating the exchange of aqueous solutions and ions between the inside and outside. Furthermore, since there is no binder between the lithium-ion sieves and they have a certain amount of space to move, the active sites are exposed to a large extent, improving the lithium extraction effect.

[0073] This invention improves the strength and thickness of the polymer membrane by coating the surface of the polymer base membrane with a polymer reinforcement membrane, such as hydrophilic sulfonated polyethersulfone, and then washing away water-soluble inorganic salts to increase the internal cavity space. This avoids the polymer base membrane from breaking or being damaged during subsequent synthesis and product application, and enhances the stability and lifespan of the formed lithium-ion adsorption material. Attached Figure Description

[0074] Figure 1 This is a schematic flowchart of the preparation method of the shaped lithium-ion adsorbent material in Example 1;

[0075] Figure 2 This is a schematic diagram of the formed lithium-ion adsorbent material in Example 1 before swelling;

[0076] Figure 3 This is a schematic diagram of the shaped lithium-ion adsorbent material after swelling in Example 1. Detailed Implementation

[0077] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0078] Those skilled in the art will understand that the embodiments described are merely illustrative of the invention and should not be construed as limiting the invention.

[0079] Example 1

[0080] This embodiment provides a molded lithium-ion adsorption material, such as Figure 1 As shown, its preparation method includes:

[0081] (1) The photoinitiator benzoin dimethyl ether, the thickener C-8 polyurethane thickener (Guangdong Zhonglian Fine Chemical Co., Ltd.), and the oil phase solvent n-hexane are mixed at a ratio of 4g:5g:100mL to prepare an oil phase solution with a viscosity of 2820mPa·s; the oil phase solvent in the oil phase solution has a lower density than water and is immiscible with water.

[0082] (2) A water-soluble inorganic salt sodium chloride, a reactive emulsifier, a lithium-depleted lithium ion sieve, and water are mixed. The reactive emulsifier is sodium hydroxypropanesulfonate methacrylate and tetraethylene glycol dimethacrylate in a molar ratio of 5:1. The lithium-depleted lithium ion sieve is λ-MnO2 with a particle size range of 10-20 μm and an average particle size of 18.4 μm. The mixture is prepared as a suspension as an aqueous solution. The mass ratio of the reactive emulsifier, the water-soluble inorganic salt, and the lithium-depleted lithium ion sieve is controlled at 0.1:2:1. The concentration of the water-soluble inorganic salt in the aqueous solution is controlled at 20 g / L.

[0083] (3) The oil phase solution is placed in a column reactor so that the liquid level of the oil phase solution is 25 cm. The oil phase solution is irradiated with ultraviolet light. Then, the aqueous phase solution is added dropwise to the oil phase solution, 250 μL each time. The droplets of the aqueous phase solution slowly sink to the bottom under the action of gravity and undergo photo-initiated reaction to form a polymer base film and encapsulate the lithium-poor state lithium ion sieve suspension. After standing and aging for 1 h, it is filtered under normal pressure and rinsed at least five times with a 1% sodium dodecyl sulfate aqueous solution (SDS) and water to obtain the spheres encapsulating the lithium-poor state lithium ion sieve suspension.

[0084] (4) According to the feeding mass ratio of 1:50, the obtained spheres coated with lithium-poor lithium ion sieve suspension were immersed in sulfonated polyethersulfone casting solution with a mass concentration of 35%. The sulfonated polyethersulfone casting solution was obtained by dissolving sulfonated polyethersulfone (Kramar, Shanghai Ziyi Reagent Factory) in DMF. The mixture was stirred for 1 hour to strengthen the casting film, form a polymer-reinforced film and coat the polymer base film to obtain reinforced spheres. After filtration under normal pressure, the obtained reinforced spheres were placed in an oven at 70°C to dry to constant weight. Then, they were soaked in water and left to stand for 48 hours. The water was changed every 12 hours to remove the water-soluble inorganic salts by washing. After filtration under normal pressure again, they were dried in an oven at 70°C to constant weight to obtain the shaped lithium ion adsorbent material.

[0085] Example 2

[0086] This embodiment provides a molded lithium-ion adsorbent material, the preparation method of which includes:

[0087] (1) The photoinitiator benzoin dimethyl ether, the thickener C-8 polyurethane thickener (Guangdong Zhonglian Fine Chemical Co., Ltd.), and the oil phase solvent n-hexane are mixed at a ratio of 4g:3g:100mL to prepare an oil phase solution with a viscosity of 2230mPa·s; the oil phase solvent in the oil phase solution has a lower density than water and is immiscible with water;

[0088] (2) A water-soluble inorganic salt sodium chloride, a reactive emulsifier, a lithium-depleted lithium ion sieve, and water are mixed. The reactive emulsifier is sodium 3-allyloxy-2-hydroxy-1-propanesulfonate and triethylene glycol dimethacrylate in a molar ratio of 8:1. The lithium-depleted lithium ion sieve is λ-MnO2 with a particle size range of 10-20 μm and an average particle size of 18.4 μm. The mixture is prepared as a suspension as an aqueous solution. The mass ratio of the reactive emulsifier, the water-soluble inorganic salt, and the lithium-depleted lithium ion sieve is controlled to be 0.2:3:1. The concentration of the water-soluble inorganic salt in the aqueous solution is controlled to be 30 g / L.

[0089] (3) The oil phase solution is placed in a column reactor so that the liquid level of the oil phase solution is 25 cm. The oil phase solution is irradiated with ultraviolet light. Then, the aqueous phase solution is added dropwise to the oil phase solution, 250 μL each time. The droplets of the aqueous phase solution slowly sink to the bottom under the action of gravity and undergo photo-initiated reaction to form a polymer base film and encapsulate the lithium-poor state lithium ion sieve suspension. After standing and aging for 1 h, it is filtered under normal pressure and rinsed at least five times with a 1% sodium dodecyl sulfate aqueous solution (SDS) and water to obtain the spheres encapsulating the lithium-poor state lithium ion sieve suspension.

[0090] (4) According to the feeding mass ratio of 1:50, the obtained spheres coated with lithium-poor lithium ion sieve suspension were immersed in sulfonated polyethersulfone casting solution with a mass concentration of 30%, wherein the sulfonated polyethersulfone casting solution was obtained by dissolving sulfonated polyethersulfone (Kramar, Shanghai Ziyi Reagent Factory) in DMF; the reaction was stirred for 1 hour to carry out casting reinforcement, forming a polymer reinforced film and coating the polymer base film to obtain reinforced spheres; after filtration under normal pressure, the obtained reinforced spheres were placed in an oven at 70°C for drying to constant weight, and then soaked in water for 48 hours, with the water changed every 12 hours to remove the water-soluble inorganic salts by washing, and then filtered again under normal pressure and dried in an oven at 70°C to constant weight to obtain the shaped lithium ion adsorbent material.

[0091] Example 3

[0092] This embodiment provides a molded lithium-ion adsorbent material, the preparation method of which includes:

[0093] (1) The photoinitiator 1-hydroxycyclohexylphenyl ketone, the thickener C-8 polyurethane thickener (Guangdong Zhonglian Fine Chemical Co., Ltd.) and the oil phase solvent n-hexane are mixed at a ratio of 4g:1g:100mL to prepare an oil phase solution with a viscosity of 1890mPa·s; the oil phase solvent in the oil phase solution has a lower density than water and is immiscible with water.

[0094] (2) A water-soluble inorganic salt sodium chloride, a reactive emulsifier, a lithium-depleted lithium ion sieve, and water are mixed. The reactive emulsifier is sodium 2-acrylamido-2-methylpropane sulfonate and polyethylene glycol (200) dimethacrylate in a molar ratio of 10:1. The lithium-depleted lithium ion sieve is λ-MnO2 with a particle size range of 10-20 μm and an average particle size of 18.4 μm. The mixture is prepared as a suspension as an aqueous solution. The mass ratio of the reactive emulsifier, the water-soluble inorganic salt, and the lithium-depleted lithium ion sieve is controlled to be 0.3:4:1. The concentration of the water-soluble inorganic salt in the aqueous solution is controlled to be 40 g / L.

[0095] (3) The oil phase solution is placed in a column reactor so that the liquid level of the oil phase solution is 25 cm. The oil phase solution is irradiated with ultraviolet light. Then, the aqueous phase solution is added dropwise to the oil phase solution, 250 μL each time. The droplets of the aqueous phase solution slowly sink to the bottom under the action of gravity and undergo photo-initiated reaction to form a polymer base film and encapsulate the lithium-poor state lithium ion sieve suspension. After standing and aging for 1 h, it is filtered under normal pressure and rinsed at least five times with a 1% sodium dodecyl sulfate aqueous solution (SDS) and water to obtain the spheres encapsulating the lithium-poor state lithium ion sieve suspension.

[0096] (4) According to the feeding mass ratio of 1:50, the obtained spheres coated with lithium-poor lithium ion sieve suspension were immersed in sulfonated polyethersulfone casting solution with a mass concentration of 25%. The sulfonated polyethersulfone casting solution was obtained by dissolving sulfonated polyethersulfone (Kramar, Shanghai Ziyi Reagent Factory) in DMF. The mixture was stirred for 1 hour to strengthen the casting film, form a polymer-reinforced film and coat the polymer base film to obtain reinforced spheres. After filtration under normal pressure, the obtained reinforced spheres were placed in an oven at 70°C to dry to constant weight, and then soaked in water for 48 hours. The water was changed every 12 hours to remove the water-soluble inorganic salts by washing. After filtration under normal pressure again, the spheres were dried in an oven at 70°C to constant weight to obtain the shaped lithium ion adsorbent material.

[0097] Example 4

[0098] This embodiment provides a molded lithium-ion adsorbent material, which is prepared by replacing lithium-poor λ-MnO2 with an equimolar amount of lithium-rich lithium-ion sieve LiMn2O4. The material is dried to constant weight in step (4) to obtain the molded material, which is then applied to the following step (5):

[0099] The molding material was added to a 0.3 mol / L hydrochloric acid solution at a solid-liquid ratio of 1 g: 100 mL. After ultrasonic degassing, the mixture was shaken in a shaker at room temperature for 24 h to fully remove lithium ions. The product was ultrasonically washed with deionized water, filtered under normal pressure, and dried in an oven at 70 °C to constant weight to complete the drying and dehydration, thus obtaining the molded lithium ion adsorbent material.

[0100] Apart from the above, all other conditions are exactly the same as in Example 2.

[0101] Example 5

[0102] This embodiment provides a molded lithium-ion adsorbent material. In step (4), the sulfonated polyethersulfone casting solution is not used to form the polymer-reinforced film. The spheres obtained in step (3) are directly placed in an oven at 70°C and dried to constant weight. Then, they are soaked in water and left to stand for 48 hours. The water is changed every 12 hours to remove the water-soluble inorganic salts by washing. After filtration under normal pressure, they are dried in an oven at 70°C to constant weight to obtain the molded lithium-ion adsorbent material.

[0103] Apart from the above, all other conditions are exactly the same as in Example 2.

[0104] Example 6

[0105] This embodiment provides a molded lithium-ion adsorbent material. In step (2), the amount of reactive emulsifier is adjusted so that the mass ratio of the reactive emulsifier, water-soluble inorganic salt, and lithium-poor lithium-ion sieve is adjusted from 0.2:3:1 to 0.1:3:1. Except for the above, the other conditions are exactly the same as in Example 2.

[0106] Example 7

[0107] This embodiment provides a molded lithium-ion adsorbent material. In step (2), the amount of reactive emulsifier is adjusted so that the mass ratio of the reactive emulsifier, water-soluble inorganic salt, and lithium-poor lithium-ion sieve is adjusted from 0.2:3:1 to 0.3:3:1. Except for the above, the other conditions are exactly the same as in Example 2.

[0108] Example 8

[0109] This embodiment provides a molded lithium-ion adsorbent material. In step (2), the amount of reactive emulsifier is adjusted so that the mass ratio of the reactive emulsifier, water-soluble inorganic salt, and lithium-poor lithium-ion sieve is adjusted from 0.2:3:1 to 0.35:3:1. Except for the above, the other conditions are exactly the same as in Example 2.

[0110] Comparative Example 1

[0111] This comparative example provides a molded lithium-ion adsorbent material, the preparation method of which includes:

[0112] λ-MnO2 and PVC were mixed and dispersed in N-methylpyrrolidone to obtain a first solution. The mass ratio of λ-MnO2, PVC and N-methylpyrrolidone was controlled to be 30:12:8. The first solution was then dripped into water with an injection agent to form particles. The particle diameter was controlled to be 2-4 mm. The obtained particles were washed with deionized water and dried at 80°C for 12 h to obtain a shaped lithium ion adsorbent material.

[0113] Comparative Example 2

[0114] This comparative example provides a molded lithium-ion adsorbent material, the preparation method of which does not use water-soluble inorganic salts, and all other conditions are exactly the same as in Example 2.

[0115] Characterization and testing:

[0116] I. Load Calculation:

[0117] Examples 1-8 are obtained by dividing the mass of the lithium ion sieve (m1) in step (2) by the mass of the dried and molded lithium ion adsorbent material particles (m2).

[0118] In Comparative Example 1, 1 ± 0.2 g (m1) of the shaped lithium-ion adsorbent material was weighed and placed in 100 mL of N-methylpyrrolidone and shaken to dissolve the PVC and release the adsorbent material. After centrifugation, the lithium-ion sieve was washed several times with water and dried at 60°C to constant weight. The mass m2 was weighed and the loading capacity was calculated as m2 / m1 × 100%, yielding a lithium-ion sieve loading capacity of 69.3%.

[0119] II. Compressive strength test:

[0120] The shaped lithium-ion adsorbent materials obtained in Examples 1-8 were immersed in water at a solid-liquid ratio of S:L = 1g:100mL and allowed to swell for 24 hours to reach swelling equilibrium.

[0121] Figure 2 This is a schematic diagram of the shaped lithium-ion adsorbent material obtained in Example 1 before swelling. It can be seen that the obtained shaped lithium-ion adsorbent material consists of spherical particles with regular shape and uniform particle size. Figure 3 This is a schematic diagram of the swollen lithium-ion adsorbent material obtained in Example 1. It can be seen that the volume of the swollen lithium-ion adsorbent material increases, but it still maintains a full and round spherical structure.

[0122] A sphere with a diameter of 3±0.2 mm from the examples and comparative examples was taken as a test sample. After slightly blotting the surface moisture with filter paper, the compressive strength of the hydrogel was tested using an INSTRON 3344 electronic universal testing machine. The compression rate was 2 mm / min. The strength at which the hydrogel ruptured (i.e., when the strength suddenly dropped) was taken as the compressive strength of the material.

[0123] III. Adsorption capacity test:

[0124] The shaped lithium-ion adsorbent materials obtained in Examples 1-8 and Comparative Example 1 were immersed in a lithium-containing solution (lithium-ion concentration 0.05 mol / L), with the solid-liquid ratio S:L = 1 g: 1000 mL controlled. The solutions were shaken at 100 rpm in a constant-temperature shaking chamber at 25°C for 24 h to ensure adsorption equilibrium was reached. The Li content in the solution was determined using ICP-OES. + The content of adsorption capacity Qe The formula for calculating (mg / g) is as follows:

[0125]

[0126] In the formula, C0 (mg / L) represents Li + The initial concentration of C; e (mg / L) is the concentration of lithium ions when adsorption equilibrium is reached; V(L) is the volume of the solution; m(g) is the mass of the lithium ion sieve.

[0127] Lithium extraction rate r in the first 2 hours E The formula for calculating (%) is as follows:

[0128]

[0129] In the formula, Q represents the adsorption capacity calculated after 2 hours of adsorption. e (mg / g) represents the adsorption capacity calculated after 24 hours of adsorption.

[0130] IV. Measurement of pore size of polymer-coated membranes:

[0131] The shaped lithium-ion adsorbent materials obtained in Examples 1-8 were brought to swelling equilibrium according to the above method. The coating layer was cut open along the diameter direction with a hand knife to release the contents. Then, it was rinsed multiple times with running water until the black powder was no longer visible. After the obtained membrane was freeze-dried, it was observed and the average pore size of the membrane was calculated using SEM.

[0132] The test results are recorded in Table 1.

[0133] Table 1

[0134]

[0135] The shaped lithium-ion adsorbent materials obtained in Examples 1-4 are encapsulated in a spherical shell with a "mesh bag" structure by simultaneously wrapping a polymer base film and a polymer reinforcement film. The lithium-ion screen is encapsulated in the internal cavity of the spherical shell, so that the lithium-ion screen has enough space to swell and facilitate ion exchange. The micron-sized pores formed on the surface of the spherical shell can realize the internal and external mass transfer of lithium ions, so that the lithium-ion screen can smoothly carry out lithium ion insertion and extraction. Therefore, it has excellent lithium extraction capacity, lithium extraction rate and cycle performance.

[0136] Compared with Example 2, the product obtained in Comparative Example 1 did not form a "net bag" structure similar to that of the present invention, so the compressive strength and average pore size of the membrane could not be tested; in Comparative Example 2, the lithium ion sieve settling speed was too fast, so it could not be completely wrapped to form the spheres, and no corresponding tests were performed.

[0137] Compared with Example 2, Example 5 does not involve reinforced casting, which not only leads to a significant decrease in compressive strength, but also results in a larger pore size on the surface of the polymer sphere, causing some lithium-ion sieves to leak out, while still encapsulating a certain amount of lithium-ion sieves, resulting in poor cycle performance.

[0138] Compared with Example 2, Examples 6-8 adjusted the amount of reactive emulsifier. Within a suitable dosage range, they all produced high-compression-strength, micron-sized pores in the molded lithium-ion adsorbent material, and exhibited excellent lithium extraction performance.

[0139] As can be seen from the above, this invention utilizes a polymer membrane with micron-sized pores to encapsulate a lithium-ion sieve to form a molded lithium-ion adsorbent material. Because the outer polymer membrane has high hydrophilicity and provides sufficient internal cavity volume for the lithium-ion sieve, the sieve can not only be fixed within the internal cavity but also swell within it, thus facilitating the exchange of aqueous solutions and ions between the inside and outside. Furthermore, since there is no binder between the lithium-ion sieves and there is a certain amount of space for movement, the active sites are exposed to a large extent, improving the lithium extraction effect. Further, this invention increases the internal cavity space by coating the surface of the polymer base membrane with a polymer reinforcing membrane, such as hydrophilic sulfonated polyethersulfone, and then washing away water-soluble inorganic salts. This effectively improves the strength and thickness of the polymer membrane, preventing breakage or damage to the polymer base membrane during subsequent synthesis and product application, and enhancing the stability and lifespan of the molded lithium-ion adsorbent material.

[0140] This invention illustrates the detailed process equipment and process flow through the above embodiments. However, this invention is not limited to the detailed process equipment and process flow described above, meaning that this invention does not necessarily depend on the detailed process equipment and process flow to be implemented. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials for the product of this invention, addition of auxiliary components, and selection of specific methods, all fall within the protection scope and disclosure scope of this invention.

[0141] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0142] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0143] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A molded lithium-ion adsorbent material, characterized in that, The invention includes a polymer membrane, which is a spherical shell with an internal cavity, and has micron-sized pores connecting the internal cavity and the outside of the spherical shell, wherein the internal cavity is filled with a lithium-ion sieve. The polymer film includes an inner polymer base film and an outer polymer reinforcement film covering the polymer base film; The lithium-ion sieve is a lithium-lean lithium-ion sieve, which includes MnO2·0.5H2O, λ-MnO2, MnO2·0.3H2O, H2TiO3, or H4Ti5O. 12 At least one of them; The shaped lithium-ion adsorbent material is prepared by the following method, the preparation method comprising: A mixed photoinitiator and thickener were prepared as an oil-phase solution. A water-soluble inorganic salt, a reactive emulsifier, and a lithium ion sieve are mixed to prepare an aqueous solution. The aqueous solution is dropped into the oil phase solution, and a photoinitiated reaction is carried out to form a polymer-based film that encapsulates the lithium-ion sieve suspension, thus obtaining spheres. The spheres are washed to remove the water-soluble inorganic salts, and then dried to obtain a shaped lithium-ion adsorbent material; the preparation method further includes casting the spheres to strengthen them, forming a polymer-reinforced film and coating the polymer base film to obtain reinforced spheres; The casting strengthening method includes immersing the sphere in sulfonated polyethersulfone casting solution and stirring for 0.5 to 2 hours. The reactive emulsifiers include bifunctional reactive emulsifiers and monofunctional reactive emulsifiers; The bifunctional reactive emulsifier includes at least one of ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, or polyethylene glycol dimethacrylate. The monofunctional reactive emulsifier includes at least one of sodium hydroxypropanesulfonate methacrylate, sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, or sodium vinylsulfonate.

2. The molded lithium-ion adsorbent material according to claim 1, characterized in that, The pore size of the micron-sized pores is 0.5~10μm.

3. The molded lithium-ion adsorbent material according to claim 1, characterized in that, The particle size of the lithium-ion sieve is larger than the pore size of the micron-sized pores.

4. The molded lithium-ion adsorbent material according to claim 1, characterized in that, The lithium ion sieve has a particle size of 10~20μm.

5. The molded lithium-ion adsorbent material according to claim 1, characterized in that, The lithium-ion sieve has a volume filling rate of less than 100% in the internal cavity.

6. A method for preparing the molded lithium-ion adsorbent material according to any one of claims 1-5, characterized in that, The preparation method includes: A mixed photoinitiator and thickener were prepared as an oil-phase solution. A water-soluble inorganic salt, a reactive emulsifier, and a lithium ion sieve are mixed to prepare an aqueous solution. The aqueous solution is dropped into the oil phase solution, and a photoinitiated reaction is carried out to form a polymer-based film that encapsulates the lithium-ion sieve suspension, thus obtaining spheres. The spheres are washed to remove the water-soluble inorganic salts, and then dried to obtain a shaped lithium-ion adsorbent material; the preparation method further includes casting the spheres to strengthen them, forming a polymer-reinforced film and coating the polymer base film to obtain reinforced spheres; The casting strengthening method includes immersing the sphere in sulfonated polyethersulfone casting solution and stirring for 0.5 to 2 hours. The reactive emulsifiers include bifunctional reactive emulsifiers and monofunctional reactive emulsifiers; The bifunctional reactive emulsifier includes at least one of ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, or polyethylene glycol dimethacrylate. The monofunctional reactive emulsifier includes at least one of sodium hydroxypropanesulfonate methacrylate, sodium 3-allyloxy-2-hydroxy-1-propanesulfonate, sodium 2-acrylamido-2-methylpropanesulfonate, or sodium vinylsulfonate.

7. The preparation method according to claim 6, characterized in that, The mass concentration of sulfonated polyethersulfone in the sulfonated polyethersulfone casting solution is 25%~35%.

8. The preparation method according to claim 6, characterized in that, The solvent in the sulfonated polyethersulfone casting solution includes at least one of N,N-dimethylformamide, dimethylacetamide, N-methylpyrrolidone, or tetrahydrofuran.

9. The preparation method according to claim 6, characterized in that, The mass ratio of the sphere to the sulfonated polyethersulfone casting solution is 1:(40~60).

10. The preparation method according to claim 6, characterized in that, The preparation method further includes washing the reinforced spheres to remove the water-soluble inorganic salts.

11. The preparation method according to claim 10, characterized in that, The washing method includes soaking in water for 24-72 hours, changing the water every 4-16 hours.

12. The preparation method according to claim 6, characterized in that, When the lithium ion sieve added in the preparation method is a lithium-rich lithium ion sieve, the preparation method further includes a delithiation treatment before drying and dehydration.

13. The preparation method according to claim 12, characterized in that, The delithiation process includes acid washing.

14. The preparation method according to claim 13, characterized in that, The pickling solution used for pickling includes hydrochloric acid with a concentration of 0.1~0.5 mol / L.

15. The preparation method according to claim 13, characterized in that, The solid-liquid ratio for pickling is (0.5~1.5)g:100mL.

16. The preparation method according to claim 13, characterized in that, The pickling time is 12-36 hours.

17. The preparation method according to claim 12, characterized in that, The lithium-rich lithium-ion sieve includes LiMn2O4, Li 1.5 Mn2O4, Li 1.33 Mn 1.67 O4, Li 1.6 Mn 1.6 O4, Li2TiO3 or Li4Ti5O 12 At least one of them.

18. The preparation method according to claim 6, characterized in that, The photoinitiator includes at least one of benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenylpropanone, or 1-hydroxycyclohexylphenyl ketone.

19. The preparation method according to claim 6, characterized in that, The thickener includes polyurethane and / or nano-silica.

20. The preparation method according to claim 6, characterized in that, The oil phase solvent in the oil phase solution has a lower density than water and is immiscible with water.

21. The preparation method according to claim 20, characterized in that, The oil phase solvent includes at least one of diethyl ether, cyclohexane, n-hexane, cyclopentane, pentane, n-heptane, isooctane, or ethyl acetate.

22. The preparation method according to claim 20, characterized in that, In the oil phase solution, the feeding ratio of the photoinitiator, thickener and oil phase solvent is 4g:(1~5)g:100mL.

23. The preparation method according to claim 6, characterized in that, The viscosity of the oil phase solution is 1000~3000 mPa·s.

24. The preparation method according to claim 6, characterized in that, The method of adding the aqueous solution to the oil phase solution includes placing the oil phase solution in a column reactor such that the liquid level of the oil phase solution is ≥25cm, and then adding the aqueous solution to the oil phase solution dropwise.

25. The preparation method according to claim 6, characterized in that, The method for carrying out the photoinitiation reaction includes irradiating the oil phase solution with an ultraviolet lamp when the aqueous phase solution is added dropwise to the oil phase solution to carry out the photoinitiation reaction.

26. The preparation method according to claim 6, characterized in that, After the photoinitiation reaction is completed, the sphere is rinsed at least five times each with a sodium dodecyl sulfate aqueous solution with a mass concentration of 0.5%~1.5% and water.

27. The preparation method according to claim 6, characterized in that, The water-soluble inorganic salt includes at least one of water-soluble lithium salt, water-soluble sodium salt, or water-soluble potassium salt.

28. The preparation method according to claim 6, characterized in that, The mass ratio of the reactive emulsifier, water-soluble inorganic salt, and lithium ion sieve is (0.1~0.3):(2~4):

1.

29. The preparation method according to claim 6, characterized in that, The concentration of the water-soluble inorganic salt in the aqueous solution is 20~40 g / L.

30. The preparation method according to claim 6, characterized in that, The molar ratio of the bifunctional reactive emulsifier to the monofunctional reactive emulsifier is 1:(5~10).

31. The use of the molded lithium-ion adsorbent material according to any one of claims 1-5, characterized in that, The applications include lithium extraction from salt lakes.

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