Manganese-based lithium ion porous adsorption membrane material, preparation method and application thereof

Abstract

The application belongs to the technical field of porous adsorption membrane materials, and discloses a manganese lithium ion porous adsorption membrane material, a preparation method and application thereof. The preparation method comprises the following steps: dispersing a carrier in an organic solvent, and then adding a film-forming polymer to form a uniform precursor solution; the carrier is a carbide, nitride or carbonitride of a two-dimensional layered transition metal; dispersing a manganese lithium composite oxide in the precursor solution to form a casting solution; coating the casting solution on a support, and then performing phase inversion through pure water to obtain a matrix membrane; placing the matrix membrane in a lithium elution solution for immersion washing, and replacing lithium ions in the matrix membrane, so that the manganese lithium ion porous adsorption membrane material is obtained. The two-dimensional layered transition metal material increases the surface area and numerous adsorption sites, and can become a connecting bridge between the manganese lithium composite oxide and the film-forming polymer through hydrogen bonds. The increased hydrogen bonds can enhance the Mn-O bond energy, thereby hindering the dissolution of non-lithium metals.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of porous adsorption membrane materials, in particular to a manganese-based lithium ion porous adsorption membrane material and a preparation method and application thereof. BACKGROUND

[0002] Lithium is widely used in energy and chemical industries, and the demand for lithium is increasing due to the rapid growth of electric vehicles and other industries. The main sources of lithium include lithium-containing ores and liquid lithium resources such as salt lake water, seawater, geothermal brine, and oil and gas exploitation wastewater. Among them, liquid lithium resources are the main source of lithium elements at present. Existing liquid lithium extraction technologies mainly include evaporation method, precipitation method, solvent extraction method, electrochemical method, membrane separation and adsorption method, etc. Among these technologies, the adsorption method is one of the main technologies for liquid lithium extraction due to its high selectivity, simple operation and high cost-effectiveness.

[0003] Existing liquid lithium adsorbent materials mainly include titanium-based adsorbents and manganese-based adsorbents. The preparation process of titanium-based adsorbents is complex and the preparation cost is high. The preparation method of manganese-based adsorbents is simple and the adsorption effect is good, but the manganese element is easy to dissolve out during repeated use, causing the failure of the adsorbent and the pollution of water quality.

[0004] Powdered lithium adsorbent is not conducive to recycling and regeneration in practical application, and is easy to cause secondary pollution of water bodies. Therefore, in the use process, the powdered lithium adsorbent is usually formed into a composite material with various polymers, such as microspheres, fibers and mixed matrix membranes. Among them, the mixed matrix membrane is a feasible scheme for liquid lithium extraction, which can effectively avoid secondary pollution without additional filtration steps in the application process. Although the mixed matrix membrane can maintain the various properties of the lithium adsorbent, the metal element in the mixed matrix membrane still has a high dissolution rate after the lithium adsorbent is prepared into a mixed matrix membrane. Therefore, preventing the dissolution of metal elements in the mixed matrix membrane during use is a technical problem to be solved in the field of liquid lithium extraction. SUMMARY

[0005] The main purpose of the present application is to provide a manganese-based lithium ion porous adsorption membrane material and a preparation method and application thereof, so as to solve the technical problem of high manganese element dissolution rate in the mixed matrix membrane in the prior art.

[0006] In order to achieve the above-mentioned purpose, according to the first aspect of the present application, a preparation method of a manganese-based lithium ion porous adsorption membrane material is provided, and the technical scheme is as follows:

[0007] The preparation method of the manganese-based lithium ion porous adsorption membrane material comprises the following steps:

[0008] The carrier is dispersed in an organic solvent, and then a film-forming polymer is added to form a uniform precursor solution; the carrier is a carbide, nitride or carbonitride of a two-dimensional layered transition metal;

[0009] dispersing the manganese lithium composite oxide in a precursor solution to form a casting solution;

[0010] coating the casting solution on a support, and then performing phase inversion by pure water to obtain a matrix film;

[0011] immersing the matrix film in a lithium elution solution to replace lithium ions in the matrix film, thereby obtaining a manganese lithium ion porous adsorption film material.

[0012] As a further improvement of the above-mentioned preparation method of the manganese lithium ion porous adsorption film material, the preparation method of the carrier is:

[0013] selectively etching the MAX phase material to obtain a MXene material;

[0014] modifying the MXene material to obtain the carrier.

[0015] As a further improvement of the above-mentioned preparation method of the manganese lithium ion porous adsorption film material:

[0016] The MAX phase material is Ti2AlC3, and the obtained MXene material is two-dimensional layered Ti3C2; Ti2AlC3 is added into a mixed solution of lithium fluoride and hydrochloric acid for water bath reaction, and after the reaction is completed, the precipitate is collected and washed to be neutral, and then vacuum dried to obtain two-dimensional layered Ti3C2;

[0017] The modification treatment is that the MXene material is immersed in a modification solution containing sodium hydroxide, ethylamine, acetamide and trimethylammonium chloride; after the immersion is completed, the solid is collected and dried; and the solid is heat treated to obtain the carrier.

[0018] As a further improvement of the above-mentioned preparation method of the manganese lithium ion porous adsorption film material:

[0019] The mass ratio of lithium fluoride to hydrochloric acid is 1:(6.57-13.13); the mass ratio of Ti2AlC3 to lithium fluoride is 1:(1-3); the water bath temperature is 30-50℃, and the water bath time is 24-72 hours;

[0020] The mass fraction of the modification solution is 3%-7%, the molar ratio of sodium hydroxide, ethylamine, acetamide and trimethylammonium chloride is 1:1:1:1; the solid-liquid ratio of the immersion is 1g:100mL, the immersion is carried out for 2-5h, then filtered, and then placed for 6-12h for drying, and then heat treated at 600-800℃ in an inert gas for 2-4h to obtain the carrier.

[0021] As a further improvement of the above-mentioned preparation method of the manganese-based lithium ion porous adsorption membrane material, the film-forming polymer is polysulfone; the organic solvent is at least one of 2-methylpyrrolidone, dimethylformamide, dimethylacetamide and dimethyl sulfoxide; the content of the film-forming polymer is 12-18 wt% based on the total mass of the film-forming polymer and the organic solvent; and the mass ratio of the film-forming polymer to the carrier in the precursor solution is 1:(0.1-0.3).

[0022] As a further improvement of the above-mentioned preparation method of the manganese-based lithium ion porous adsorption membrane material, the manganese lithium composite oxide is prepared by calcining a mixture of a lithium source and a manganese source in an air atmosphere, and then cooling to obtain the manganese lithium composite oxide.

[0023] As a further improvement of the above-mentioned preparation method of the manganese-based lithium ion porous adsorption membrane material, the lithium source is at least one of lithium carbonate, lithium hydroxide and lithium nitrate; the manganese source is at least one of manganese carbonate, manganese oxide, manganese dioxide, dimanganese trioxide and manganese acetate; the molar ratio of lithium to manganese in the mixture is 1:(1.0-2.0); the calcination temperature is 350-750°C, and the calcination time is 2-12 hours.

[0024] As a further improvement of the above-mentioned preparation method of the manganese-based lithium ion porous adsorption membrane material, the mass ratio of the film-forming polymer to the manganese lithium composite oxide in the casting solution is 1:(1-3).

[0025] To achieve the above-mentioned purpose, according to the second aspect of the present application, a manganese-based lithium ion porous adsorption membrane material is provided, and the technical solution is as follows:

[0026] The manganese-based lithium ion porous adsorption membrane material is prepared by the preparation method of the manganese-based lithium ion porous adsorption membrane material according to the above-mentioned first aspect; the average roughness value of the material is 31.5 nm, the contact angle is 86.66°, and the FTIR spectrum has characteristic peaks at 909 cm -1 , 650 cm -1 , and 613 cm -1 .

[0027] To achieve the above-mentioned purpose, according to the third aspect of the present application, the application of the manganese-based lithium ion porous adsorption membrane material is provided, and the technical solution is as follows:

[0028] A lithium extraction method, in which the manganese-based lithium ion porous adsorption membrane material prepared by the preparation method according to the above-mentioned first aspect is put into a lithium-containing solution to adsorb lithium elements; or the manganese-based lithium ion porous adsorption membrane material prepared by the preparation method according to the above-mentioned first aspect is used to filter a lithium-containing solution.

[0029] The manganese-based lithium ion porous adsorption film material, the preparation method and the application have the following advantages: the two-dimensional layered transition metal material is innovatively introduced, the surface area and the numerous adsorption sites are increased, the adsorption capacity is improved, the hydrogen bond can be a connecting bridge between the manganese-lithium composite oxide and the film-forming polymer, the increased hydrogen bond can enhance the Mn-O bond energy, thereby hindering the dissolution of non-lithium metal, and the adsorption energy of lithium ions is lower than that of other metal ions, so that the dissolution of non-lithium metal elements can be effectively prevented under the premise of ensuring high adsorption capacity and high selectivity, and the technical problem of high dissolution rate of the mixed matrix membrane in the prior art is effectively solved.

[0030] The application will be further described below in conjunction with the drawings and specific embodiments. Additional aspects and advantages of the application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The drawings that form a part of this application are used to aid in the understanding of the application, and the content provided by the drawings and the related description in the application can be used to explain the application, but do not constitute improper limitations on the application.

[0032] Figure 1 XRD patterns of LMO and HMO.

[0033] Figure 2 SEM photos of LMO.

[0034] Figure 3 SEM photos of Ti3C2-MXene.

[0035] Figure 4 SEM photos of the cross section of PSF.

[0036] Figure 5 SEM photos of the cross section of LMO / MXene / PSF.

[0037] Figure 6 SEM photos of the cross section of HMO / MXene / PSF.

[0038] Figure 7 SEM photos of the surface of HMO / MXene / PSF.

[0039] Figure 8 EDX element mapping image of the surface of HMO / MXene / PSF.

[0040] Figure 9 Stress-strain curves of PSF and HMO / MXene / PSF.

[0041] Figure 10 FTIR spectra of PSF, HMO / PSF and HMO / MXene / PSF.

[0042] Figure 11 N2 adsorption-desorption isotherm and pore size distribution of PSF.

[0043] Figure 12 N2 adsorption-desorption isotherm and pore size distribution of HMO / MXene / PSF.

[0044] Figure 13 Cycling stability of HMO / MXene / PSF in LiCl aqueous solution.

[0045] Figure 14 Cycling stability of HMO / MXene / PSF in SGW.

[0046] Figure 15 Performance of HMO / MXene / PSF in filtering LiCl aqueous solution.

[0047] Figure 16 Performance of HMO / MXene / PSF in filtering SGW. DETAILED DESCRIPTION

[0048] The present application will be described in detail below with reference to the drawings. Those skilled in the art will be able to implement the present application based on these descriptions. Before the present application is disclosed with reference to the drawings, it is particularly pointed out that:

[0049] The technical solutions and technical features provided in each part of the present application, including the following description, can be combined with each other without conflict.

[0050] In addition, the embodiments of the present application involved in the following description are generally only embodiments of part of the present application, not all embodiments. Therefore, based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0051] Regarding the terms and units in the present application. The terms "include", "have" and any variations thereof in the specification and claims of the present application and related parts are intended to cover non-exclusive inclusion.

[0052] The specific embodiments of the manganese-based lithium ion porous adsorption membrane material and the preparation method thereof of the present application are as follows:

[0053] (1) dispersing the carrier in an organic solvent, and then adding a film-forming polymer to form a uniform precursor solution; the carrier is a carbide, nitride or carbonitride of a two-dimensional layered transition metal;

[0054] (2) dispersing the manganese-lithium composite oxide in the precursor solution to form a casting solution;

[0055] (3) coating the casting solution on a support, and then performing phase inversion by pure water to obtain a matrix film;

[0056] (4) immersing the matrix film in a lithium elution solution to replace the lithium ions in the matrix film, thereby obtaining a manganese-based lithium ion porous adsorption film material.

[0057] In step (1), the carrier is prepared by: etching a MAX phase material to obtain a MXene material; and modifying the MXene material to obtain the carrier.

[0058] The MXene is a two-dimensional layered Ti3C2, and the corresponding MAX phase material is Ti2AlC3. The Ti2AlC3 is added into a mixed solution of lithium fluoride and hydrochloric acid for water bath reaction. After the reaction is completed, the precipitate is collected and washed to neutral, and then vacuum dried to obtain the two-dimensional layered Ti3C2. Preferably, the mass ratio of lithium fluoride to hydrochloric acid is 1:(6.57-13.13); the mass ratio of lithium fluoride to Ti2AlC3 is 1:(1-3); the water bath temperature is 30-50℃, and the water bath time is 24-72 hours.

[0059] The modification treatment is: immersing the MXene material in a modification solution containing sodium hydroxide, ethylamine, acetamide and trimethylammonium chloride; collecting and drying the solid after the immersion is completed; and heat treating the solid to obtain the carrier. Preferably, the mass fraction of the modification solution is 3%-7%, the molar ratio of sodium hydroxide, ethylamine, acetamide and trimethylammonium chloride is 1:1:1:1; the solid-liquid ratio of immersion is 1g:100mL, the solid is filtered after being immersed for 2-5h, and then dried after being left to stand for 6-12h. Then, the solid is heat treated at 600-800℃ in an inert gas for 2-4h to obtain the carrier.

[0060] Preferably, the film-forming polymer is polysulfone; the organic solvent is at least one of 2-methylpyrrolidone, dimethylformamide, dimethylacetamide and dimethyl sulfoxide; and the content of the film-forming polymer is 12-18wt% based on the total mass of the film-forming polymer and the organic solvent.

[0061] Preferably, the mass ratio of the film-forming polymer to the carrier in the precursor solution is 1:(0.1-0.3).

[0062] In step (2), the manganese lithium composite oxide is prepared by calcining a mixture of a lithium source and a manganese source in an air atmosphere, and then cooling to obtain the manganese lithium composite oxide; preferably, the lithium source is at least one selected from lithium carbonate, lithium hydroxide, and lithium nitrate; the manganese source is at least one selected from manganese carbonate, manganese oxide, manganese dioxide, and manganese acetate; the molar ratio of lithium to manganese in the mixture is 1:(1.0-2.0); the calcination temperature is 350-750°C, and the calcination time is 2-12 hours.

[0063] Preferably, the mass ratio of the film-forming polymer to the manganese lithium composite oxide in the casting solution is 1:(1-3).

[0064] In step (3), the support is a glass surface, a polypropylene non-woven fabric, or a polyester resin non-woven fabric, and the thickness of the casting knife is 200 μm.

[0065] In step (4), the lithium elution solution is hydrochloric acid with a concentration of 0.5-1.5 mol / L, and the immersion time is 12-24 hours; after the hydrochloric acid immersion, the obtained manganese lithium ion porous adsorption membrane material is washed with ultrapure water and then stored in pure water.

[0066] The specific implementation of the lithium extraction method of the present application is that the manganese lithium ion porous adsorption membrane material prepared by the above preparation method is placed in a lithium-containing solution to adsorb lithium; or the manganese lithium ion porous adsorption membrane material prepared by the above preparation method is used to filter a lithium-containing solution.

[0067] The beneficial effects of the present application are illustrated by the following examples and test data.

[0068] Example 1: The preparation steps of the manganese lithium ion porous adsorption membrane material of the present example are as follows:

[0069] 1 g of lithium fluoride is dissolved in 40 mL of a hydrochloric acid solution to obtain a mixture (the mass ratio of lithium fluoride to hydrochloric acid is 1:13.13), 1 g of Ti2AlC3 is weighed and added to the mixture (the mass ratio of Ti2AlC3 to lithium fluoride is 1:1), and the reaction is carried out at 30°C in a water bath for 48 hours; after the reaction is completed, repeated washing and centrifugation are carried out until the solution is neutral, and then the two-dimensional layered Ti3C2 is obtained after vacuum drying at 60°C, which is denoted as Ti3C2-MXene.

[0070] 1 g of Ti3C2-MXene is dispersed in 100 mL of a modification solution with a mass fraction of 5.2%, and the molar ratio of sodium hydroxide, ethylamine, acetamide, and trimethylammonium chloride is 1:1:1:1; after 3 hours of immersion, filtration is carried out, and then the solution is left to stand for 9 hours and then dried; then, the carrier is obtained by heat treatment at 700°C in an inert gas for 3 hours.

[0071] 0.16 g of the carrier was weighed and dispersed in 8.4 g of 2-methylpyrrolidone, and then 1.6 g of polysulfone was added to form a uniform precursor solution; the mass ratio of polysulfone to carrier in the precursor solution was 1:0.1; and the content of polysulfone was 16 wt% based on the total mass of polysulfone and 2-methylpyrrolidone.

[0072] The lithium carbonate and manganese carbonate were mixed and uniformly used as a mixed powder (the molar ratio of lithium element to manganese element was 1:1.25), and then the mixed powder was calcined at 500°C for 4 hours in an air atmosphere, and after cooling, a manganese lithium composite oxide was obtained, denoted as LMO.

[0073] The LMO was dispersed in the precursor solution to form a uniform casting solution; the mass ratio of polysulfone to LMO in the casting solution was 1:2.

[0074] The casting solution was coated on a polyester resin non-woven fabric, and then a substrate membrane was obtained after phase inversion by pure water, denoted as LMO / MXene / PSF.

[0075] The LMO / MXene / PSF was placed in 1 mol / L hydrochloric acid for 24 hours, and the lithium ions in the manganese lithium composite oxide structure in the LMO / MXene / PSF were replaced out, and after hydrochloric acid immersion, the material was washed with ultrapure water to obtain a manganese-based lithium ion porous adsorption membrane material, denoted as HMO / MXene / PSF.

[0076] Test results show that the lithium adsorption capacity of the HMO / MXene / PSF of the embodiment is 16.58 mg / g, and the manganese element dissolution loss rate is 1.35%.

[0077] Example 2: Compared with Example 1, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the embodiment is that the amount of the carrier is adjusted, so that the mass ratio of polysulfone to carrier in the precursor solution is 1:0.2.

[0078] Test results show that the lithium adsorption capacity of the HMO / MXene / PSF of the embodiment is 18.81 mg / g, and the manganese element dissolution loss rate is 0.45%.

[0079] Example 3: Compared with Example 1, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the embodiment is that the amount of the carrier is adjusted, so that the mass ratio of polysulfone to carrier in the precursor solution is 1:0.3.

[0080] Test results show that the lithium adsorption capacity of the HMO / MXene / PSF of the embodiment is 19.01 mg / g, and the manganese element dissolution loss rate is 0.13%.

[0081] Example 4: Compared with Example 2, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the present embodiment is that the amount of LMO is adjusted so that the mass ratio of polysulfone to LMO in the casting solution is 1:2.5.

[0082] Tested, the lithium adsorption capacity of HMO / MXene / PSF of the present embodiment is 19.99 mg / g, and the manganese element dissolution loss rate is 0.54%.

[0083] Example 5: Compared with Example 2, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the present embodiment is that the amount of LMO is adjusted so that the mass ratio of polysulfone to LMO in the casting solution is 1:1.

[0084] Tested, the lithium adsorption capacity of HMO / MXene / PSF of the present embodiment is 17.57 mg / g, and the manganese element dissolution loss rate is 0.24%.

[0085] Example 6: Compared with Example 2, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the present embodiment is that the amount of LMO is adjusted so that the mass ratio of polysulfone to LMO in the casting solution is 1:1.5.

[0086] Tested, the lithium adsorption capacity of HMO / MXene / PSF of the present embodiment is 15.65 mg / g, and the manganese element dissolution loss rate is 0.31%.

[0087] Example 7: Compared with Example 2, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the present embodiment is that the amount of LMO is adjusted so that the mass ratio of polysulfone to LMO in the casting solution is 1:3.

[0088] Tested, the lithium adsorption capacity of HMO / MXene / PSF of the present embodiment is 23.80 mg / g, and the manganese element dissolution loss rate is 0.83%.

[0089] Example 8: Compared with Example 4, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the present embodiment is that the concentration of hydrochloric acid is adjusted so that the mass ratio of lithium fluoride to hydrochloric acid in the mixed solution is 1:6.57.

[0090] Tested, the lithium adsorption capacity of HMO / MXene / PSF of the present embodiment is 19.43 mg / g, and the manganese element dissolution loss rate is 0.64%.

[0091] Example 9: Compared with Example 4, the difference between the preparation method of the manganese-based lithium ion porous adsorption membrane material of the present embodiment is that the concentration of hydrochloric acid is adjusted so that the mass ratio of lithium fluoride to hydrochloric acid in the mixed solution is 1:10.21.

[0092] The lithium adsorption amount of the HMO / MXene / PSF of the embodiment is 19.67 mg / g, and the manganese element dissolution loss rate is 0.61%.

[0093] Example 10: Compared with Example 9, the difference between the preparation method of the manganese-based lithium ion porous adsorption film material of the embodiment is that the amount of manganese carbonate is adjusted so that the molar ratio of lithium element to manganese element in the mixed powder is 1:1.

[0094] The lithium adsorption amount of the HMO / MXene / PSF of the embodiment is 17.54 mg / g, and the manganese element dissolution loss rate is 0.35%.

[0095] Example 11: Compared with Example 9, the difference between the preparation method of the manganese-based lithium ion porous adsorption film material of the embodiment is that the amount of manganese carbonate is adjusted so that the molar ratio of lithium element to manganese element in the mixed powder is 1:2.

[0096] The lithium adsorption amount of the HMO / MXene / PSF of the embodiment is 18.23 mg / g, and the manganese element dissolution loss rate is 0.83%.

[0097] Example 12: Compared with Example 9, the difference between the preparation method of the manganese-based lithium ion porous adsorption film material of the embodiment is that the amount of Ti2AlC3 is adjusted so that the mass ratio of Ti2AlC3 to lithium fluoride is 1:2.

[0098] The lithium adsorption amount of the HMO / MXene / PSF of the embodiment is 18.98 mg / g, and the manganese element dissolution loss rate is 0.72%.

[0099] Example 13: Compared with Example 9, the difference between the preparation method of the manganese-based lithium ion porous adsorption film material of the embodiment is that the amount of Ti2AlC3 is adjusted so that the mass ratio of Ti2AlC3 to lithium fluoride is 1:3.

[0100] The lithium adsorption amount of the HMO / MXene / PSF of the embodiment is 19.12 mg / g, and the manganese element dissolution loss rate is 0.71%.

[0101] In the above embodiments, Example 7 is the most preferred embodiment. On the basis of Example 7, a control test is carried out to fully illustrate the lithium adsorption mechanism of the HMO / MXene / PSF of the present application.

[0102] Control Example 1: Directly using hydrochloric acid to treat LMO to obtain a powdery manganese-based lithium ion adsorption material, denoted as HMO.

[0103] Control Example 2: A polysulfone film is formed alone, and the obtained film is denoted as PSF.

[0104] Example 3: No support was used, LMO was directly dispersed in polysulfone and organic solvent, the film before elution was denoted as LMO / PSF, and the film formed after elution was denoted as HMO / PSF.

[0105] The test obtained the manganese element dissolution loss rates of HMO, HMO / PSF, and HMO / MXene / PSF as 14.17%, 8.58%, and 0.42% respectively, indicating the effectiveness of strong hydrogen bonds in reducing manganese loss.

[0106] Example 4: Ti3C2-MXene was directly used, i.e., Ti3C2-MXene and polysulfone were dispersed in 2-methylpyrrolidone to form a uniform precursor solution. The test obtained the lithium adsorption capacity of the film material of this comparative example as 18.65 mg / g, which was greatly reduced compared to Example 7, indicating that the functional groups (hydroxyl -OH, amine -NH2, quaternary ammonium salt -N+(CH3)3, amide -CONH2) introduced by modification can significantly improve the lithium adsorption effect.

[0107] The average roughness (Ra) value of PSF was 6.75 nm, and the Ra value of HMO / MXene / PSF was 31.5 nm. It can be seen that the addition of nanoparticles significantly changed the film surface texture, thereby affecting the surface morphology and permeability. The film with a rough surface showed enhanced surface area, thereby enhancing the water flux and adsorption capacity of the film.

[0108] The test obtained the contact angle of PSF as 81.39°, and the contact angle of HMO / MXene / PSF as 86.66°. It can be seen that the increase in surface roughness increased the contact area between the solid and liquid phases, thus increasing the apparent geometric surface area and enhancing the surface hydrophobicity.

[0109] Figure 1 is the XRD pattern of LMO. As shown in Figure 1 , the XRD pattern of LMO is consistent with the original cubic spinel structure of Li 1.33 Mn 1.67 O4(card No. PDF018-0026). The spinel peak of the XRD pattern of HMO slightly shifts to a higher 2θ value, and this shift is attributed to the Li + / H + exchange reaction during the elution process.

[0110] Figure 2 is the SEM photo of LMO. As shown in Figure 2 , LMO shows a nanosheet morphology.

[0111] Figure 3 is the SEM photo of Ti3C2-MXene. As shown in Figure 3As shown, Ti3C2-MXene has a layered structure with nanosheets closely stacked.

[0112] Figure 4 SEM image of the cross-section of PSF. Figure 5 SEM image of the cross-section of LMO / MXene / PSF. Figure 6 SEM image of the cross-section of HMO / MXene / PSF. Figure 7 SEM image of the surface of HMO / MXene / PSF. Figure 8 EDX elemental mapping image of the surface of HMO / MXene / PSF. As shown, Figures 4-5 The membrane porosity of LMO / MXene / PSF increased significantly after loading Ti3C2-MXene and LMO compared to PSF. As shown, Figures 6-7 The surface porosity of HMO / MXene / PSF increased significantly compared to LMO / MXene / PSF, indicating that excess loading material was removed during the washing process. As shown, Figure 8 C, O, Mn, F, Cl, Ti and S were uniformly distributed in HMO / MXene / PSF.

[0113] The percentages of C, O, Mn, Ti obtained by X-ray photoelectron spectroscopy (XPS) analysis were 50.34wt%, 23.84wt%, 24.31wt%, 0.5wt%, respectively.

[0114] Figure 9 Stress-strain curves of PSF and HMO / MXene / PSF. As shown, Figure 9 HMO / MXene / PSF exhibited a maximum tensile stress of 1.75 MPa and a strain of 112.10%, both of which were slightly lower than PSF.

[0115] Figure 10 FTIR spectra of PSF, HMO / PSF and HMO / MXene / PSF. As shown, Figure 10 Compared with PSF and HMO / PSF, HMO / MXene / PSF showed vibration peaks at 909 cm -1 , 650 cm -1 , 613 cm -1 , indicating that the lithium adsorption process was the exchange of hydrogen and lithium in HMO.

[0116] Figure 11 N2 adsorption-desorption isotherm and pore size distribution of PSF. Figure 12 N2 adsorption-desorption isotherm and pore size distribution of HMO / MXene / PSF. As shown, Figures 11-12As shown, the N2 adsorption-desorption isotherms all accord with typical type IV isotherms with H3 type hysteresis loop, indicating the existence of mesopores. The surface area of PSF is 18.55 m 2 / g, while HMO / MXene / PSF shows a significantly increased surface area of 36.98 m 2 / g. The pore size distribution also shows that the membrane pore size has changed more obviously after loading LMO and Ti3C2-MXene, the average pore size of PSF is 25.63 nm, while the average pore size of HMO / MXene / PSF is 11.83 nm.

[0117] In the adsorption performance test, the test method of lithium adsorption capacity is: adding membrane material in a glass bottle containing LiCl aqueous solution (pH = 12), oscillating on a rotary shaker at a speed of 200 rpm for 72 hours, and the lithium adsorption capacity (q e ) is calculated using the following formula:

[0118]

[0119] The dominant distribution coefficient (K d ) is calculated using the following formula:

[0120]

[0121] Wherein, q e (mg / g) is the lithium adsorption capacity, indicating the adsorption capacity at equilibrium; V (L) represents the volume of LiCl aqueous solution; m (g) represents the mass of HMO / MXene / PSF, C0 and C e represent the initial concentration and equilibrium concentration of lithium ions in LiCl aqueous solution (mg / L), respectively.

[0122] The manganese element loss rate is the percentage of the mass of manganese element in the solution after the adsorption reaction is completed to the mass of manganese element in HMO / MXene / PSF, wherein the mass of manganese element in HMO / MXene / PSF is calculated according to the amount of manganese source, and the mass of manganese element in the solution after the adsorption reaction is completed is calculated by detecting the concentration of manganese element through inductively coupled plasma optical emission spectrometry (ICP-OES) test.

[0123] Shale gas wastewater (SGW) is used to adsorb and filter lithium, and the initial concentrations of main metal ions in SGW are: 25.6 mg / L Li + , 7810 mg / L Na + , 251 mg / L K + , 239 mg / L Ca 2+ , 364.5 mg / L Ba 2+The adsorption effect of HMO / MXene / PSF on SGW is shown in Table 1.

[0124] Table 1

[0125] Metal ion Initial concentration (mg / L) Equilibrium concentration (mg / L) Adsorption capacity (mg / g) K d (mL / g) Li + ]]> 25.6 15.01 21.18 1411.06 Na + ]] 7810 7802 16 2.05 K + ]]> 251 245.3 11.4 46.47 Ca 2+ ]]> 239 236.52 4.96 20.97 Ba 2+ ]]> 364.5 363 3 8.26

[0126] As shown in Table 1, the lithium adsorption capacity of HMO / MXene / PSF on SGW is 21.18 mg / g, while the sodium adsorption capacity is 16 mg / g, the potassium adsorption capacity is 11.4 mg / g, the calcium adsorption capacity is 4.96 mg / g, and the barium adsorption capacity is 3 mg / g. The calculated K of HMO / MXene / PSF on lithium ion is 1411.06 mL / g, which is significantly higher than that of other ions, indicating that the affinity for lithium ion adsorption is higher and has good selectivity. d

[0127] The adsorbed lithium ions were removed by acid washing, and then subsequent adsorption cycles were carried out to evaluate the regeneration performance of HMO / MXene / PSF. Figure 13 Figure is a cycle stability diagram of HMO / MXene / PSF in LiCl aqueous solution. Figure 14 Figure is a cycle stability diagram of HMO / MXene / PSF in SGW. As shown in Figures 13-14 , the lithium adsorption capacity after each regeneration remained relatively stable in LiCl aqueous solution and SGW, and had excellent use stability.

[0128] The flux of PSF and HMO / MXene / PSF was evaluated using a Merck Millipore stirred device (8050, USA), and the diameter of the filtration module was 4 cm. The filtration was carried out at a transmembrane pressure (TMP) of 0.04 MPa. The flux was calculated using the following formula:

[0129]

[0130] In the formula, J (L / m 2 h) is the flux; Q (L) is the volume of filtrate obtained, Δt (h) is the time interval, A (m 2 ) is the operating surface area of the membrane material, which is 12.56 cm 2 .

[0131] When the filtration liquid is pure water, the pure water flux of PSF is only 10 L / m 2 / h, while the pure water flux of HMO / MXene / PSF is 120 L / m 2 / h.

[0132] Figure 15 Figure is a performance diagram of HMO / MXene / PSF filtering LiCl aqueous solution. Figure 16 ​The performance graph of HMO / MXene / PSF filter SGW. As shown in Figures 15-16 Fig. 7, when the filtering liquid is LiCl aqueous solution (C0is 20.5 mg / L), the lithium ion concentration reaches the maximum value when the filtrate volume is 200 mL. When the filtering liquid is SGW (C0is 25.6 mg / L), the lithium ion concentration reaches the maximum value when the filtrate volume is 160 mL. It can be seen that the HMO / MXene / PSF of the present application can adsorb lithium while filtering.

[0133] The above-mentioned test and characterization equipment are as follows:

[0134] The roughness was analyzed by atomic force microscopy (AFM) using Bruker Multimode 8.

[0135] The contact angle (CA) was measured using a contact angle measuring instrument.

[0136] The XRD pattern was collected using a X-ray diffractometer of Japan SHIMADZU, using Cu Kα radiation target (40 kV, 30 mA).

[0137] The SEM photo and EDX element mapping image were collected using a scanning electron microscope (SEM) of Germany ZEISS.

[0138] The stress-strain curve was analyzed using a UTM5305H tensile tester.

[0139] The X-ray photoelectron spectroscopy (XPS) test was collected using Thermo ESCALAB 250XI.

[0140] The Fourier transform infrared (FT-IR) spectrum was collected using Agilent 1260.

[0141] The specific surface area was determined by QUADRASORB SI, and the pore structure was determined by Brunauer-Emmett-Teller (BET).

[0142] The inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the concentration of lithium ions and other ions, and the specific model was Optima 8000.

[0143] The above-mentioned related content of the present application has been described. The person skilled in the art will be able to implement the present application on the basis of these descriptions. On the basis of the above-mentioned content of the present application, all other embodiments obtained by the person skilled in the art without making creative efforts shall belong to the protection scope of the present application.​

Claims

1. A method for preparing a manganese-based lithium ion porous adsorption membrane material, characterized in that: The method comprises the following steps: dispersing the carrier in an organic solvent, and then adding a film-forming polymer to form a uniform precursor solution; the carrier is a carbide, nitride or carbonitride of a two-dimensional layered transition metal; dispersing a manganese-lithium composite oxide in the precursor solution to form a casting solution; coating the casting solution on a support, and then performing phase inversion by using pure water to obtain a matrix film; immersing the matrix film in a lithium elution solution to replace lithium ions in the matrix film, thereby obtaining a manganese-based lithium ion porous adsorption film material; the preparation method of the carrier is: selectively etching a MAX phase material to obtain a MXene material; the MAX phase material is Ti2AlC3, and the obtained MXene material is a two-dimensional layered Ti3C2; adding Ti2AlC3 into a mixed solution of lithium fluoride and hydrochloric acid to perform a water bath reaction, collecting and washing the precipitate to be neutral after the reaction is completed, and vacuum drying to obtain the two-dimensional layered Ti3C2; performing modification treatment on the MXene material to obtain the carrier; the modification treatment is: immersing the MXene material in a modification solution containing sodium hydroxide, ethylamine, acetamide and trimethylammonium chloride; collecting and drying the solid after the immersion is completed; and performing heat treatment on the solid to obtain the carrier; the mass fraction of the modification solution is 3% to 7%, the molar ratio of sodium hydroxide, ethylamine, acetamide and trimethylammonium chloride is 1:1:1:1; the solid-liquid ratio of the immersion is 1g:100mL, the immersion is performed for 2 to 5 hours, then filtration is performed, the solid is then dried after being placed for 6 to 12 hours, and then heat treatment is performed on the solid in an inert gas at 600 to 800℃ for 2 to 4 hours to obtain the carrier.

2. The method of claim 1, wherein: the mass ratio of lithium fluoride to hydrochloric acid is 1:(6.57-13.13); the mass ratio of Ti2AlC3 to lithium fluoride is 1:(1-3); the water bath temperature is 30-50℃, and the water bath time is 24-72 hours.

3. The method of claim 1, wherein the manganese-based lithium ion porous adsorption membrane material is prepared by the following steps: (1) preparing a manganese-based lithium ion porous adsorption membrane material precursor; (2) sintering the manganese-based lithium ion porous adsorption membrane material precursor to obtain the manganese-based lithium ion porous adsorption membrane material. the film-forming polymer is polysulfone; the organic solvent is at least one of 2-methylpyrrolidone, dimethylformamide, dimethylacetamide and dimethyl sulfoxide; the content of the film-forming polymer is 12-18wt% based on the total mass of the film-forming polymer and the organic solvent; and the mass ratio of the film-forming polymer to the carrier in the precursor solution is 1:(0.1-0.3).

4. The method of claim 1, wherein the manganese-based lithium ion porous adsorption membrane material is prepared by the following steps: (1) preparing a manganese-based lithium ion porous adsorption membrane material precursor; (2) sintering the manganese-based lithium ion porous adsorption membrane material precursor to obtain a manganese-based lithium ion porous adsorption membrane material. The preparation method of the manganese-lithium composite oxide is: calcining a mixed powder composed of a lithium source and a manganese source in an air atmosphere, and obtaining the manganese-lithium composite oxide after cooling.

5. The method for preparing the manganese-based lithium-ion porous adsorption membrane material as described in claim 4, characterized in that: The lithium source is at least one of lithium carbonate, lithium hydroxide and lithium nitrate; the manganese source is at least one of manganese carbonate, manganese oxide, manganese dioxide, dimanganese trioxide and manganese acetate; the molar ratio of lithium to manganese in the mixed powder is 1:(1.0-2.0); the calcination temperature is 350-750℃, and the calcination time is 2-12 hours.

6. The method for preparing the manganese-based lithium-ion porous adsorption membrane material as described in claim 1, characterized in that: The mass ratio of the film-forming polymer to the manganese-lithium composite oxide in the casting solution is 1:(1-3).

7. A manganese-based lithium ion porous adsorption membrane material, characterized in that: The manganese-based lithium ion porous adsorption membrane material is prepared by the method in any one of claims 1-6; the average roughness value of the material is 31.5 nm, the contact angle is 86.66°, and the FTIR spectrum has characteristic peaks at 909 cm -1 , 650 cm -1 , and 613 cm -1 .

8. Process for the extraction of lithium, characterized in that: The manganese-based lithium ion porous adsorption membrane material prepared by the preparation method in any one of claims 1-6 is placed in a lithium-containing solution to adsorb lithium elements; or the manganese-based lithium ion porous adsorption membrane material prepared by the preparation method in any one of claims 1-6 is used to filter a lithium-containing solution.

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