Lithium ion porous adsorption membrane material, preparation method and application thereof

Abstract

The application discloses a lithium ion porous adsorption film material with significantly improved lithium adsorption performance and a preparation method and application thereof. The preparation method of the lithium ion porous adsorption film material comprises the following steps: (1) obtaining a matrix film, wherein the matrix film is obtained by coating a casting solution containing a MXene nanosheet dispersion liquid, a lithium-containing composite oxide and a film-forming polymer, and performing phase inversion; the MXene nanosheet is a single-layer Ti3C2; (2) preparing a weak alkaline precursor solution in an ice water bath, wherein the weak alkaline precursor solution contains a lithium salt and dopamine; (3) immersing the matrix film into the weak alkaline precursor solution in the ice water bath, and reacting under near-infrared light irradiation to obtain a precursor film; (4) immersing the precursor film into a glutaraldehyde solution to react, and obtaining a composite film; and (5) performing acid pickling and lithium removal treatment on the composite film, and obtaining the lithium ion porous adsorption film material.

Description

Technical Field

[0001] This invention relates to the technical field of porous adsorption membrane materials, and more specifically, to lithium-ion porous adsorption membrane materials, their preparation methods, and applications. Background Technology

[0002] Lithium is widely used in the energy and chemical industries, and its demand is constantly increasing, driven by the rapid growth of industries such as electric vehicles. The main sources of lithium include lithium-bearing ores and liquid lithium resources such as salt lake water, seawater, geothermal brine, and oil and gas extraction wastewater, with liquid lithium resources currently being the primary source of lithium. Existing liquid lithium extraction technologies mainly include evaporation, precipitation, solvent extraction, electrochemical methods, membrane separation, and adsorption. Among these technologies, adsorption has become one of the main liquid lithium extraction technologies due to its high selectivity, ease of operation, and cost-effectiveness.

[0003] The effectiveness of adsorption technology depends on developing functional adsorbents with high adsorption capacity, ion selectivity, and structural stability. Currently, liquid lithium extraction adsorbents mainly include manganese-based lithium ion sieves and titanium-based lithium ion sieves. Manganese-based lithium ion sieves are simple to prepare and have good adsorption effects, but manganese is easily leached out during repeated use, causing adsorbent failure and water pollution. Titanium-based lithium ion sieves are more stable, and titanium is less prone to leaching. Among titanium-based lithium ion sieves, H₂TiO₃ and H₄Ti₅O₃... 12 Especially noteworthy is the former, which possesses a stable crystal structure, superior adsorption / desorption properties, and excellent cycle stability.

[0004] Powdered lithium adsorbents are difficult to recover and regenerate in practical applications, and can easily cause secondary pollution of water bodies. Therefore, in use, powdered lithium adsorbents are usually combined with various polymers to form composite materials, such as microspheres, fibers, and mixed matrix membranes. Among these, mixed matrix membranes are a feasible solution for liquid lithium extraction, eliminating the need for additional filtration steps and effectively avoiding secondary pollution. Therefore, integrating H2TiO3 with mixed matrix membranes, utilizing the high adsorption efficiency of H2TiO3 and the structural stability and selective permeability of the membrane, has become the optimal method for lithium recovery. However, even with the integration of H2TiO3 with mixed matrix membranes, and despite the many advantages of H2TiO3, the adsorption capacity of titanium-based lithium ion sieves based on H2TiO3 and mixed matrix membranes still needs further enhancement.

[0005] Chinese invention patent CN119771176B discloses a titanium-based porous adsorption membrane material for lithium ions, its self-assembly preparation method, and its applications. By fixing MXene nanosheets onto a polysulfone matrix membrane as an in-situ growth substrate for titanium-lithium composite oxides, the nanoparticles of the titanium-lithium composite oxide self-assemble in situ on the surface of the MXene nanosheets through hydrogen bonding and van der Waals interactions, forming a spindle-shaped nanostructure with a larger specific surface area. This minimizes surface energy, significantly enhances lithium-ion transport, and improves adsorption capacity. However, porous adsorption membrane materials based on lithium-ion exchange layers only exhibit high selectivity and adsorption capacity for lithium under strongly alkaline conditions. In neutral or acidic environments, the adsorption performance significantly decreases because hydrogen ions and competing cations preferentially occupy active sites. Surface modification is an effective strategy to address this problem. For example, dopamine can self-polymerize on the material surface to form polydopamine, introducing amine and phenolic hydroxyl groups with affinity for lithium, thereby improving adsorption performance. Existing dopamine polymerization methods typically involve direct self-polymerization of dopamine, which is not only slow but also results in the polydopamine layer being prone to detachment, unevenness, and easy coverage of active adsorption sites, hindering efficient lithium ion adsorption. Summary of the Invention

[0006] The technical problem to be solved by this invention is to provide a porous lithium-ion adsorption membrane material with significantly improved lithium adsorption performance, its preparation method and application, and the technical solution is as follows: A method for preparing lithium-ion porous adsorption membrane materials includes the following steps: (1) Obtaining a matrix membrane, wherein the matrix membrane is obtained by coating and phase inversion of a casting solution containing MXene nanosheet dispersion, lithium-containing composite oxide and film-forming polymer; the MXene nanosheet is a single layer of Ti3C2; (2) Prepare a weakly alkaline precursor solution in an ice-water bath, wherein the weakly alkaline precursor solution contains lithium salt and dopamine; (3) The matrix membrane is immersed in a weakly alkaline precursor solution under ice-water bath conditions and reacted under near-infrared light irradiation to obtain the precursor membrane. (4) The precursor membrane is immersed in glutaraldehyde solution to react and obtain the composite membrane; (5) The composite membrane is subjected to acid washing and delithiation treatment to obtain lithium ion porous adsorption membrane material.

[0007] As a further improvement to the above preparation method: in step (1), the lithium-containing composite oxide is a titanium-lithium composite oxide; the film-forming polymer is polysulfone; in the casting solution, the mass fraction of polysulfone is 14-18 wt%, and the mass ratio of the sum of the mass of polysulfone and MXene nanosheet dispersion to the mass of titanium-lithium composite oxide is 1:(2-4).

[0008] As a further improvement to the above preparation method: in step (2), the pH of the weakly alkaline precursor solution is 8 to 9, the lithium salt is lithium chloride with a concentration of 0.4 to 0.6 g / L, the concentration of dopamine is 0.8 to 1.2 g / L, and the temperature of the ice-water bath is 0 to 5 °C.

[0009] As a further improvement to the above preparation method: in step (3), the height difference between the matrix membrane and the surface of the weakly alkaline precursor liquid is 2-10 mm, the height difference between the surface of the weakly alkaline precursor liquid and the near-infrared light source is 5-15 cm, and the power of the near-infrared light source is 0.5-1 W / cm.

[0010] As a further improvement to the above preparation method: first incubate under light-protected conditions for 20 to 40 minutes, and then turn on near-infrared light irradiation; use pulsed irradiation, with an irradiation cycle of: turn on irradiation for 1 to 2 minutes and then turn off irradiation for 2 to 3 minutes, and repeat 5 to 10 times.

[0011] As a further improvement to the above preparation method: in step (4), the mass fraction of glutaraldehyde solution is 0.8-1.2%; the surface of the precursor film is first rinsed with pure water, and then immersed in glutaraldehyde solution for 10-30 minutes.

[0012] As a further improvement to the above preparation method: in step (5), the composite membrane is immersed in hydrochloric acid solution and subjected to acid washing and lithium removal treatment under near-infrared light irradiation.

[0013] As a further improvement to the above preparation method: the concentration of hydrochloric acid solution is 0.05-0.5 mol / L, the height difference between the composite membrane and the hydrochloric acid solution surface is 2-10 mm, the height difference between the hydrochloric acid solution surface and the near-infrared light source is 5-15 cm, the power of the near-infrared light source is 0.2-0.5 W / cm, and the irradiation time is 1-3 hours.

[0014] The lithium-ion porous adsorption membrane material is prepared by the above-described preparation method.

[0015] The lithium extraction method involves placing the lithium-ion porous adsorption membrane material prepared by the above preparation method into a lithium-containing solution to adsorb lithium; or, the lithium-ion porous adsorption membrane material prepared by the above preparation method is used to filter the lithium-containing solution.

[0016] The lithium-ion porous adsorption membrane material, its preparation method, and its application of the present invention have the following advantages: (1) MXene nanosheets (monolayer Ti3C2) in the matrix film are a top-level near-infrared photothermal conversion material. Due to the strong localized surface plasmon resonance (LSPR) effect, it has strong light absorption in the near-infrared region (e.g., 808nm). In this invention, the reaction system is placed in an ice-water bath, and the bulk solution is at a low temperature. Dopamine hardly undergoes self-polymerization. However, at the same time, the matrix film surface is irradiated with near-infrared light. The Ti3C2 on the film surface absorbs the near-infrared light and instantly generates local high temperature (up to 50-60℃), driving dopamine to undergo ultra-fast and high-density polymerization only on the film surface and the inner wall of the pores.

[0017] (2) In this invention, lithium salt is added when preparing a weakly alkaline precursor solution, so that dopamine undergoes self-assembly and polymerization around lithium ions (lithium ions coordinate with the phenolic hydroxyl groups of dopamine). After subsequent acid washing and delithiation treatment, the lithium ions in the polydopamine layer can be washed away, leaving holes that match the size and charge of lithium ions, forming a lithium ion imprinted polymer layer, thereby achieving specific recognition and adsorption of lithium ions.

[0018] (3) After polymerization under near-infrared light irradiation and before acid elution and lithium removal, cross-linking reaction is still carried out. Through the cross-linking reaction between glutaraldehyde and active groups such as amino and hydroxyl groups in the polydopamine structure, the linear or low-cross-linked polydopamine molecular network is further locked to form a denser and stronger three-dimensional network structure. In the subsequent acid elution and lithium removal process and in future actual use, the size and shape of the cavities left after elution of lithium ions are kept stable, and the collapse or deformation of these specific adsorption pores is avoided, which would lead to a decrease in adsorption selectivity.

[0019] Therefore, the lithium-ion porous adsorption membrane material, its preparation method, and its application of the present invention are simple, ingenious, easy to control, and easy to operate. On the one hand, by utilizing the excellent near-infrared photothermal conversion performance of Ti3C2, dopamine is rapidly, densely, and uniformly polymerized only on the membrane surface and the inner wall of the pores. On the other hand, after delithiation by acid washing, specific holes matching lithium are formed, which greatly enhances the selective adsorption capacity of the membrane for lithium ions and significantly improves the lithium extraction performance of the membrane material, especially significantly improving the lithium extraction performance of the membrane material under weakly alkaline or even neutral or weakly acidic conditions, thus possessing greater practicality.

[0020] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The accompanying drawings, which form part of this invention, are used to aid in understanding the invention. The content provided in the drawings and their related descriptions can be used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a SEM image of the surface of the PDA / Ni-HTO / MXene / PSF according to an embodiment of the present invention.

[0022] Figure 2 This is a SEM image of the cross-section of the PDA / Ni-HTO / MXene / PSF according to an embodiment of the present invention. Detailed Implementation

[0023] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that: The technical solutions and features provided in the various parts of this invention, including the following description, can be combined with each other without conflict.

[0024] Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0025] Regarding the terminology and units used in this invention: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this invention are intended to cover non-exclusive inclusion.

[0026] Example:

[0027] The lithium-ion porous adsorption membrane material and its preparation method in this embodiment include the following steps: (1) A monolayer Ti3C2 dispersion and a titanium-lithium composite oxide (referred to as Ni-LTO) were prepared according to the preparation method disclosed in Chinese Invention Patent CN119771176B. Polysulfone (as a film-forming polymer, denoted as PSF) was first dissolved in the monolayer Ti3C2 dispersion, and then Ni-LTO was added to prepare a casting solution. The mass fraction of polysulfone was 16 wt%, and the mass ratio of the sum of the masses of polysulfone and the monolayer Ti3C2 dispersion to the mass of Ni-LTO was 1:3. The casting solution was coated on a polypropylene nonwoven fabric, and then phase inversion was performed with pure water to obtain the matrix film.

[0028] (2) Prepare a weakly alkaline precursor solution with pH=8.5 in an ice-water bath environment with a temperature of 0 to 5℃. The concentration of lithium chloride in the weakly alkaline precursor solution is 0.5 g / L and the concentration of dopamine is 1 g / L.

[0029] (3) Immerse the matrix membrane in the weakly alkaline precursor solution maintained under ice-water bath conditions, and adjust the height difference between the matrix membrane and the precursor solution surface to 6 mm. First, incubate the system for 30 minutes under light-protected conditions. After incubation, turn on the near-infrared light source to irradiate the reaction, adjust the height difference between the weakly alkaline precursor solution surface and the near-infrared light source to 10 cm, and set the power of the near-infrared light source to 0.8 W / cm. The irradiation process adopts a pulsed operation: turn on the irradiation for 1.5 minutes and then turn off the irradiation for 2 minutes, repeating this cycle 8 times. After the reaction is completed, remove the membrane to obtain the precursor membrane.

[0030] (4) First, rinse the surface of the precursor membrane thoroughly with pure water, then immerse it in a 1% glutaraldehyde solution and let it stand for 20 minutes to react. After the reaction is complete, the composite membrane is obtained.

[0031] (5) Immerse the composite membrane in a 0.2 mol / L hydrochloric acid solution, controlling the height difference between the composite membrane and the hydrochloric acid solution surface to be 6 mm, and the height difference between the hydrochloric acid solution surface and the near-infrared light source to be 10 cm. Set the power of the near-infrared light source to 0.4 W / cm. Irradiate continuously under these conditions for 2 hours. After the reaction is complete, remove the membrane, clean and dry it to obtain the final lithium-ion porous adsorption membrane material (denoted as PDA / Ni-HTO / MXene / PSF).

[0032] Figure 1 This is a SEM image of the surface of the PDA / Ni-HTO / MXene / PSF in this embodiment. Figure 2 This is a SEM image of the cross-section of the PDA / Ni-HTO / MXene / PSF in this embodiment. (Example:) Figure 1 As shown, the membrane material surface has a dense and uniformly distributed layer of particles. For example... Figure 2 As shown, the membrane material has a dense structure with uniform thickness.

[0033] Atomic force microscopy (AFM) analysis showed that the average roughness (Ra) of HTO / MXene / PSF (from Chinese invention patent CN119771176B, the same below) was 33.9 nm, while the Ra value of PDA / Ni-HTO / MXene / PSF was 99.3 ± 0.1 nm. This enhanced roughness is expected to increase the interface area and enhance the interaction between lithium ions and the surface.

[0034] The wettability results showed that the contact angle of HTO / MXene / PSF was 83.50°, while the contact angle of PDA / Ni-HTO / MXene / PSF decreased to approximately 23°. Simultaneously, the underwater oil contact angle of HTO / MXene / PSF was 112°, while that of PDA / Ni-HTO / MXene / PSF in this embodiment was 155°. This demonstrates that PDA / Ni-HTO / MXene / PSF exhibits excellent hydrophilicity and underwater oil repellency, ensuring effective wetting regulation and antifouling performance during the lithium extraction process.

[0035] The specific surface area results show that the specific surface area of ​​HTO / MXene / PSF is 38.44 m². 2 / g, the specific surface area of ​​PDA / Ni-HTO / MXene / PSF increased to 46.47m². 2 / g.

[0036] Stress-strain results show that PDA / Ni-HTO / MXene / PSF has a moderate strength of 3.8 MPa, while the maximum elongation reaches 19.5%, demonstrating excellent flexibility and structural strengthening performance.

[0037] Under neutral pH conditions, the zeta potential of HTO / MXene / PSF is approximately -29 mV, while that of PDA / Ni-HTO / MXene / PSF is approximately -51 mV. This significant negative potential promotes electrostatic attraction with positively charged lithium ions, thereby improving lithium ion enrichment efficiency and interfacial transport performance. Furthermore, the increased negative surface charge is expected to enhance colloidal stability in aqueous solutions and inhibit particle aggregation.

[0038] In the adsorption performance test, the lithium adsorption capacity was tested as follows: 0.5 g / L of membrane material was added to 50 mL of SGW (shale gas wastewater with a lithium ion concentration of 25.6 mg / L), and the solution was shaken at 200 rpm for 24 hours on a rotary shaker. The lithium adsorption capacity was then measured. q e Use the following formula to calculate: ; in, q e (mg / g) represents the lithium adsorption capacity, indicating the adsorption capacity at equilibrium. V (L) represents the volume of the SGW; m (g) indicates the mass of PDA / Ni-HTO / MXene / PSF. C 0 and C e These represent the initial and equilibrium concentrations (mg / L) of lithium ions in the SGW, respectively.

[0039] Tests showed that when the pH of SGW was adjusted to 3-12, the lithium adsorption capacity of PDA / Ni-HTO / MXene / PSF was significantly higher than that of HTO / MXene / PSF. Specifically, when pH=8 (close to the natural pH of SGW, 7.92), the lithium adsorption capacity of PDA / Ni-HTO / MXene / PSF was 33.64 mg / g, which was much higher than that of HTO / MXene / PSF, which was 18.19 mg / g.

[0040] The titanium dissolution rate is the percentage of the titanium mass in the solution after the adsorption reaction compared to the titanium mass in the PDA / Ni-HTO / MXene / PSF. The titanium mass in the PDA / Ni-HTO / MXene / PSF is calculated based on the amount of titanium source used. The titanium mass in the solution after the adsorption reaction is determined by detecting the titanium concentration using inductively coupled plasma optical emission spectroscopy (ICP-OES) before calculation. Tests showed that when the pH of the SGW varied between 3 and 12, the titanium dissolution rate of the PDA / Ni-HTO / MXene / PSF remained consistently <0.003%, exhibiting excellent structural stability.

[0041] Adsorbed lithium ions were removed by acid washing, followed by subsequent adsorption cycles to evaluate the regeneration performance of the PDA / Ni-HTO / MXene / PSF membrane. Tests showed that the PDA / Ni-HTO / MXene / PSF membrane maintained a high adsorption capacity of over 33 mg / g throughout 20 cycles with almost no degradation, indicating excellent chemical stability and structural recoverability of its interfacial structure.

[0042] The lithium extraction performance of the PDA / Ni-HTO / MXene / PSF filter was evaluated using a Merck Millipore stirred filter (8050, USA) with a filter module diameter of 4 cm, and filtration was performed at a transmembrane pressure (TMP) of 0.04 MPa. When filtering SGW at pH=8, the lithium ion concentration in the filtrate filtered with HTO / MXene / PSF reached its maximum at a filtrate volume of 210 mL, while the corresponding filtrate volume for PDA / Ni-HTO / MXene / PSF was 335 mL. This demonstrates that the PDA / Ni-HTO / MXene / PSF of this invention not only adsorbs lithium during filtration but also achieves higher filtration efficiency.

[0043] Compare with Example 1 Compared with the examples, the lithium-ion porous adsorption membrane material of this comparative example differs in step (3): without incubation, the near-infrared light source is directly turned on for irradiation reaction.

[0044] The lithium adsorption capacity of the membrane material in this control example was tested to be 30.25 mg / g. This demonstrates that dark incubation before near-infrared light irradiation helps the catechol groups of dopamine capture lithium ions, thereby forming effective and specific adsorption pores.

[0045] Compare with Example 2 Compared with the examples, the lithium-ion porous adsorption membrane material of this comparative example differs in step (3): the irradiation process does not use pulsed operation, but is directly irradiated for 12 minutes.

[0046] The lithium adsorption capacity of the membrane material in this control example was tested to be 29.18 mg / g. It is evident that prolonged continuous irradiation with near-infrared light may cause heat to gradually diffuse outwards from the membrane surface, leading to heating of the liquid layer adhering to the membrane surface and thus weakening the confinement effect. However, by using pulsed irradiation, the cooling bath rapidly removes residual heat during the "off" intervals, while fresh dopamine and lithium ions have time to diffuse into the depths of the membrane material's pores, allowing the polydopamine layer and specific pores to grow deeper and more uniformly into the pores.

[0047] Compare with Example 3 Compared with the examples, the lithium-ion porous adsorption membrane material of this comparative example differs in step (5): instead of using a near-infrared light source for irradiation, the composite membrane is directly immersed in hydrochloric acid solution and then taken out for cleaning and drying.

[0048] Tests showed that the lithium adsorption capacity of the membrane material after immersion for 2 hours was 27.38 mg / g, and after immersion for 8 hours it was 31.94 mg / g. This indicates that turning on near-infrared light during the acid leaching and delithiation stage may cause the localized micro-heat generated by Ti3C2 to induce a slight "thermal expansion" in the polydopamine framework, greatly accelerating the kinetic rate of lithium ion diffusion from the imprinted pores and the underlying titanium lithium oxide, thereby significantly improving the efficiency of the acid leaching and delithiation process.

[0049] Compare with Example 4 Compared with the examples, the lithium-ion porous adsorption membrane material of this comparative example differs in that it adopts conventional polymerization and crosslinking methods: the matrix membrane is immersed in a weakly alkaline precursor solution at room temperature, and after soaking for 3 hours, it is taken out and then immersed in glutaraldehyde solution for 20 minutes, and then the same steps (5) are performed.

[0050] Testing revealed that the lithium adsorption capacity of the membrane material in this comparative example was 21.42 mg / g, significantly lower than that of the PDA / Ni-HTO / MXene / PSF obtained through the novel polymerization and crosslinking methods of the embodiments. Furthermore, the membrane material in this comparative example exhibited poor stability, with the lithium adsorption capacity decreasing to 19.23 mg / g after 10 cycles.

[0051] The equipment used in the above experiments and characterizations is as follows: SEM images were taken using a scanning electron microscope (SEM) from ZEISS, Germany.

[0052] Roughness was analyzed using atomic force microscopy (AFM) with Bruker Multimode 8.

[0053] The contact angle (CA) was measured using a KRÜSS ADVANCE contact angle measuring instrument.

[0054] The stress-strain curves were analyzed using a UTM5305H tensile testing instrument.

[0055] Specific surface area was determined by QUADRASORB SI, and pore structure was determined by Brunauer-Emmett-Teller (BET).

[0056] Inductively coupled plasma optical emission spectroscopy (ICP-OES) is used to determine the concentration of lithium ions and other ions; the specific model is Optima 8000.

[0057] The foregoing has described the relevant content of the present invention. Those skilled in the art will be able to implement the present invention based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A method for preparing lithium-ion porous adsorption membrane materials, characterized in that: Includes the following steps: (1) Obtaining a matrix membrane, wherein the matrix membrane is obtained by coating and phase inversion of a casting solution containing MXene nanosheet dispersion, lithium-containing composite oxide and film-forming polymer; MXene nanosheets are monolayer Ti3C2; (2) Prepare a weakly alkaline precursor solution in an ice-water bath, wherein the weakly alkaline precursor solution contains lithium salt and dopamine; (3) The matrix membrane is immersed in a weakly alkaline precursor solution under ice-water bath conditions and reacted under near-infrared light irradiation to obtain the precursor membrane. (4) The precursor membrane is immersed in glutaraldehyde solution to react and obtain the composite membrane; (5) The composite membrane is subjected to acid washing and delithiation treatment to obtain lithium ion porous adsorption membrane material.

2. The preparation method according to claim 1, characterized in that: In step (1), the lithium-containing composite oxide is a titanium-lithium composite oxide; the film-forming polymer is polysulfone; in the casting solution, the mass fraction of polysulfone is 14-18 wt%, and the mass ratio of the sum of the mass of polysulfone and MXene nanosheet dispersion to the mass of titanium-lithium composite oxide is 1:(2-4).

3. The preparation method according to claim 1, characterized in that: In step (2), the pH of the weakly alkaline precursor solution is 8-9, the lithium salt is lithium chloride with a concentration of 0.4-0.6 g / L, the concentration of dopamine is 0.8-1.2 g / L, and the temperature of the ice-water bath is 0-5℃.

4. The preparation method according to claim 1, characterized in that: In step (3), the height difference between the matrix membrane and the surface of the weakly alkaline precursor solution is 2-10 mm, the height difference between the surface of the weakly alkaline precursor solution and the near-infrared light source is 5-15 cm, and the power of the near-infrared light source is 0.5-1 W / cm.

5. The preparation method according to claim 4, characterized in that: Incubate for 20-40 minutes in the dark, then turn on the near-infrared light irradiation; use pulsed irradiation, with the irradiation cycle being: turn on the irradiation for 1-2 minutes and then turn off the irradiation for 2-3 minutes, repeating 5-10 times.

6. The preparation method according to claim 1, characterized in that: In step (4), the mass fraction of the glutaraldehyde solution is 0.8-1.2%; the surface of the precursor membrane is first rinsed with pure water and then immersed in the glutaraldehyde solution for 10-30 minutes.

7. The preparation method according to claim 1, characterized in that: In step (5), the composite membrane is immersed in hydrochloric acid solution and subjected to acid washing and lithium removal treatment under near-infrared light irradiation.

8. The preparation method according to claim 7, characterized in that: The concentration of the hydrochloric acid solution is 0.05–0.5 mol / L, the height difference between the composite membrane and the hydrochloric acid solution surface is 2–10 mm, the height difference between the hydrochloric acid solution surface and the near-infrared light source is 5–15 cm, the power of the near-infrared light source is 0.2–0.5 W / cm, and the irradiation time is 1–3 hours.

9. A lithium-ion porous adsorption membrane material, characterized in that: It is prepared by the preparation method according to any one of claims 1-8.

10. A method for lithium extraction, characterized in that: The lithium-ion porous adsorption membrane material prepared by the preparation method according to any one of claims 1-8 is placed in a lithium-containing solution to adsorb lithium; or, the lithium-ion porous adsorption membrane material prepared by the preparation method according to any one of claims 1-8 is used to filter the lithium-containing solution.

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