Composite lithium extraction adsorbent and preparation method therefor and use thereof

Abstract

The present disclosure provides a composite lithium extraction adsorbent and a preparation method therefor and a use thereof. The preparation method comprises the following steps: (1) mixing a manganese-based adsorbent, a first solvent, and an amino modifier, and carrying out a one-step reaction to obtain an amino-modified adsorbent; (2) mixing the amino-modified adsorbent, a zinc salt, tetra(4-carboxyphenyl)porphine, pyrazine, N,N-dimethylacetamide, and a second solvent, and carrying out a two-step reaction to obtain an adsorbent composite organic metal framework material; and (3) mixing a sulfo modifier, the adsorbent composite organic metal framework material, and a third solvent, carrying out a three-step reaction to obtain a hydrophilic lithium extraction adsorbent, and carrying out acid leaching treatment to obtain the composite lithium extraction adsorbent. By means of the method of the present disclosure, a composite lithium extraction adsorbent having low dissolution loss rate and high adsorption selectivity and permeability can be prepared.

Description

A composite lithium extraction adsorbent and its preparation method and application Technical Field

[0001] The present invention belongs to the technical field of lithium extraction from salt lakes and relates to a composite lithium extraction adsorbent and a preparation method and application thereof. Background Art

[0002] Lithium and lithium compounds, as a crucial strategic resource, are widely used in industries such as energy, aerospace, alloy materials, ceramics, construction, and the chemical industry. Naturally, lithium resources primarily exist in liquid forms, including lithium ore, salt lake brine, and seawater. Nearly 80% of my country's liquid lithium resources are located in salt lakes in Qinghai and Tibet. However, due to the inherent disadvantage of high magnesium-to-lithium ratios in my country's salt lakes, commercial lithium ore extraction technologies applied to salt lakes still suffer from low lithium content and purity. Therefore, research on lithium extraction from salt lake brine is of great strategic significance for the development and utilization of lithium resources. Currently, the main methods for extracting lithium from salt lakes include precipitation, solvent extraction, evaporation and crystallization, calcination and leaching, salting out, carbonization, electrodialysis, molten salt electrolysis, and adsorption.

[0003] Among them, adsorption has become one of the most promising methods for extracting lithium from salt lake brine in my country due to its simple process, environmental friendliness, and low cost. Currently, adsorption technology for lithium extraction from salt lakes primarily uses ion sieve adsorbents, including manganese-based lithium ion sieves, aluminum-based lithium ion sieves, and titanium-based lithium ion sieves.

[0004] CN108543521A discloses a fiber adsorbent and preparation method for extracting lithium from salt lake brine. The method comprises preparing a ceramic fiber with a loose inner core, graphitizing the inner core, adsorbing a lithium source and a manganese source, and calcining the resultant to obtain a lithium-manganese composite oxide. The lithium-manganese composite oxide is in a fibrous form in the inner core of the ceramic fiber, and lithium is removed by acid elution.

[0005] CN108636341A discloses a method for forming a lithium-extracting adsorbent, which uses a titanium-type lithium ion sieve or a manganese-type lithium ion sieve as the adsorbent raw powder, dissolves a polymer in an organic solvent to prepare a binder, and uses a rotational molding method to form the adsorbent raw powder into balls.

[0006] The manganese adsorbent prepared by the above scheme has a high theoretical lithium ion adsorption capacity, but has poor permeability and a high dissolution rate, resulting in a sharp decrease in adsorption capacity after repeated use.

[0007] Summary of the Invention

[0008] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0009] The purpose of the present disclosure is to provide a composite lithium extraction adsorbent and its preparation method and application. The method described in the present disclosure can produce a composite lithium extraction adsorbent with low dissolution rate and high adsorption selectivity and permeability.

[0010] To achieve this purpose, the present disclosure adopts the following technical solutions:

[0011] In a first aspect, the present disclosure provides a method for preparing a composite lithium extraction adsorbent, the preparation method comprising the following steps:

[0012] (1) mixing a manganese-based adsorbent, a first solvent, and an amino modifier to obtain an amino-modified adsorbent through a one-step reaction;

[0013] (2) mixing an amino-modified adsorbent, zinc salt, tetrakis(4-carboxyphenyl)porphine, pyrazine, N,N-dimethylacetamide, and a second solvent, and performing a two-step reaction to obtain an adsorbent composite organic metal framework material;

[0014] (3) mixing the sulfonic modifier, the adsorbent composite organic metal framework material and the third solvent, obtaining a hydrophilic lithium extraction adsorbent through a three-step reaction, and then subjecting the mixture to an acid leaching treatment to obtain the composite lithium extraction adsorbent.

[0015] After the manganese-based adsorbent is modified with amino groups, the amino groups on the surface of the manganese-based adsorbent react with the carboxyl groups on the ligands in the metal organic framework (Zn-MOF is formed by the reaction of zinc salt and tetrakis (4-carboxyphenyl) porphine), thereby fixing the manganese inside the metal organic framework with high water stability, thereby reducing the dissolution loss of manganese. The two-dimensional metal organic framework material prepared by the method of the present disclosure has high porosity and a pore size of 0.78-0.81nm, between Li + (0.764nm) and Mg 2+ The hydrated ion radius of the metal organic framework is between 0.824 nm and 0.866 nm, which is beneficial for improving the lithium ion selectivity of the composite adsorbent. Modification of the sulfonic acid groups grafted onto the metal organic framework can make it superhydrophilic and improve the adsorption capacity of the adsorbent.

[0016] In one embodiment, the first solvent in step (1) comprises ethanol.

[0017] In one embodiment, the amino modifier includes 3-aminopropyltriethoxysilane.

[0018] In one embodiment, the mass ratio of the manganese-based adsorbent to the amino modifier is (10-15):1, for example: 10:1, 11:1, 12:1, 14:1 or 15:1.

[0019] In one embodiment, the one-step reaction in step (1) comprises a water bath reaction.

[0020] In one embodiment, the temperature of the one-step reaction is 40-50°C, for example, 40°C, 42°C, 45°C, 48°C or 50°C.

[0021] In one embodiment, the one-step reaction time is 12 to 24 hours, for example, 12 hours, 15 hours, 18 hours, 20 hours or 24 hours.

[0022] After the manganese-based adsorbent is modified by grafting amino groups on the present invention, the amino groups on the manganese-based adsorbent can undergo an acylation reaction with the carboxyl groups on meso-tetrakis(4-carboxyphenyl)porphine, which is beneficial for the subsequent in situ generation of an organic metal framework on its surface. The meso-tetrakis(4-carboxyphenyl)porphine in the organic ligand is preferentially adsorbed, so that the metal-organic framework grows uniformly on the adsorbent surface and the binding is more stable.

[0023] In one embodiment, the zinc salt in step (2) includes any one of zinc nitrate, zinc sulfate or zinc chloride, or a combination of at least two thereof.

[0024] In one embodiment, the tetrakis(4-carboxyphenyl)porphine comprises meso-tetrakis(4-carboxyphenyl)porphine.

[0025] In one embodiment, the mass volume ratio of the amino-modified adsorbent and N,N-dimethylacetamide is 1:(1-3) g / mL, for example: 1:1 g / mL, 1:1.5 g / mL, 1:2 g / mL, 1:2.5 g / mL or 1:3 g / mL.

[0026] In one embodiment, the second solvent comprises polyvinylpyrrolidone.

[0027] In one embodiment, the molar ratio of the zinc salt, N,N-dimethylacetamide, and tetrakis(4-carboxyphenyl)porphine is (6-9):(2-5):1, for example: 6:2:1, 7:3:1, 8:2:1, 9:5:1 or 8:4:1.

[0028] In one embodiment, the two-step reaction in step (2) includes stirring after a hydrothermal reaction.

[0029] In one embodiment, the temperature of the hydrothermal reaction is 80-200°C, for example, 80°C, 100°C, 120°C, 150°C or 200°C.

[0030] In one embodiment, the hydrothermal reaction time is 2 to 9 hours, for example, 2 hours, 4 hours, 5 hours, 8 hours or 9 hours.

[0031] In one embodiment, the stirring speed is 200-400 rpm, for example, 200 rpm, 250 rpm, 300 rpm, 350 rpm or 400 rpm.

[0032] In one embodiment, the stirring time is 3 to 6 hours, for example, 3 hours, 3.5 hours, 4 hours, 5 hours or 6 hours.

[0033] In one embodiment, the sulfonic modifier in step (3) includes 1,3-propanedisulfonic acid.

[0034] In one embodiment, the third solvent comprises deionized water.

[0035] In one embodiment, the mass ratio of the sulfonic modifier to the adsorbent composite organic metal framework material is 1:(1.5-4.5), for example: 1:1.5, 1:2, 1:3, 1:4 or 1:4.5.

[0036] In one embodiment, the temperature of the three-step reaction in step (3) is 50-70°C, for example, 50°C, 55°C, 60°C, 65°C or 70°C.

[0037] In one embodiment, the three-step reaction time is 18 to 24 hours, for example, 18 hours, 20 hours, 22 hours, 23 hours or 24 hours.

[0038] In one embodiment, the three-step reaction is followed by centrifugation and washing.

[0039] In one embodiment, the detergent of the washing treatment comprises water and acetone.

[0040] In one embodiment, the acid solution for the acid leaching treatment in step (3) comprises hydrochloric acid and / or sulfuric acid.

[0041] In one embodiment, the concentration of the acid solution is 0.25 to 0.5 mol / L, for example, 0.25 mol / L, 0.3 mol / L, 0.35 mol / L, 0.4 mol / L or 0.5 mol / L.

[0042] In one embodiment, the acid leaching treatment time is 12 to 48 hours, for example: 12 hours, 16 hours, 18 hours, 20 hours, 24 hours or 48 hours.

[0043] The acid leaching time will affect the performance of the adsorbent. If the time is too short, the lithium ion leaching will be insufficient. If the leaching time is too long, excessive acidification will occur, resulting in Mn dissolution.

[0044] In a second aspect, the present disclosure provides a composite lithium extraction adsorbent, which is prepared by the method described in the first aspect.

[0045] In a third aspect, the present disclosure provides an application of the composite lithium extraction adsorbent as described in the second aspect, wherein the composite lithium extraction adsorbent is used for extracting lithium from salt lakes.

[0046] Compared with the prior art, the present disclosure has the following beneficial effects:

[0047] (1) The present invention prepares a metal-organic framework with high water stability. After the manganese-based adsorbent is modified by amino grafting, the surface amino adsorbent carboxyl groups on the metal-organic framework undergo acylation reaction, thereby fixing the manganese-based adsorbent inside the metal-organic framework. The present invention fixes the manganese-based adsorbent inside the metal-organic framework, which can not only reduce the dissolution loss of manganese, but also improve the lithium ion selectivity of the composite adsorption material.

[0048] (2) The present invention discloses that the modification of the sulfonic acid groups grafted on the metal organic framework can make it super hydrophilic, thereby improving the adsorption capacity of the adsorbent. In addition, the metal organic framework material structure is relatively stable, thus avoiding the instability problem caused by the dissolution loss of the hydrophilic polymer during the use of the adsorbent formed by the currently commonly used hydrophilic polymers such as sodium alginate or polysaccharide coated ion sieve.

[0049] (3) The adsorption capacity of the composite lithium extraction adsorbent disclosed in the present invention can reach more than 16.88 mg / g, the lithium ion recovery rate can reach more than 93.5%, the dissolution loss rate can reach less than 0.0009%, and the adsorption efficiency maintained after 10 cycles can reach more than 94.06%.

[0050] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0051] The technical solution of the present disclosure is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present disclosure and should not be regarded as specific limitations of the present disclosure.

[0052] The manganese-based adsorbents described in the examples and comparative examples of the present disclosure were prepared by the following method:

[0053] LiOH and Mn2O3 were mixed uniformly in a molar ratio of 1.05:1 and calcined at 550°C for 12 h to obtain a manganese-based adsorbent.

[0054] Example 1

[0055] This embodiment provides a composite lithium extraction adsorbent, and the preparation method of the composite lithium extraction adsorbent is as follows:

[0056] (1) A manganese-based adsorbent was dispersed in ethanol under ultrasound assistance, 3-aminopropyltriethoxysilane was added at a mass ratio of 12:1 between the adsorbent and 3-aminopropyltriethoxysilane, and the mixture was reacted in a water bath at 45°C for 18 h. The obtained product was washed with ethanol and dried in vacuo at 90°C to obtain an amino-modified adsorbent;

[0057] (2) The amino-modified adsorbent was placed in N,N-dimethylacetamide at a solid-liquid ratio of 1 g:2 mL and ultrasonically dispersed for 20 minutes to obtain a suspension. Zinc sulfate was added to hydrothermally react with meso-tetra(4-carboxyphenyl)porphine, pyrazine and polyvinylpyrrolidone for 6 hours and then stirred for 4 hours. The stirring rate was 300 rpm and the reaction temperature was 130°C. After washing and drying, the adsorbent composite organic metal framework material was obtained. The molar ratio of zinc sulfate, N,N-dimethylacetamide and meso-tetra(4-carboxyphenyl)porphine was 7:4:1.

[0058] (3) 1,3-propanedisulfonic acid was dissolved in deionized water, and the adsorbent composite organic metal framework material was added at a mass ratio of 1,3-propanedisulfonic acid to the adsorbent composite organic metal framework material of 1:3, and the mixture was reacted at a temperature of 60°C for 21 hours. After the reaction was completed, the mixture was centrifuged, and the supernatant was removed. After washing with water and acetone, the mixture was placed in a hydrochloric acid solution with a concentration of 0.35 mol / L and immersed for 24 hours to obtain the composite lithium extraction adsorbent.

[0059] Example 2

[0060] This embodiment provides a composite lithium extraction adsorbent, and the preparation method of the composite lithium extraction adsorbent is as follows:

[0061] (1) A manganese-based adsorbent was dispersed in ethanol under ultrasound assistance, 3-aminopropyltriethoxysilane was added at a mass ratio of 15:1 between the adsorbent and 3-aminopropyltriethoxysilane, and the mixture was reacted in a water bath at 50°C for 12 h. The obtained product was washed with ethanol and dried in vacuo at 90°C to obtain an amino-modified adsorbent;

[0062] (2) The amino-modified adsorbent was placed in N,N-dimethylacetamide at a solid-liquid ratio of 1 g:3 mL and ultrasonically dispersed for 20 minutes to obtain a suspension. Zinc sulfate was added to hydrothermally react with meso-tetra(4-carboxyphenyl)porphine, pyrazine and polyvinylpyrrolidone for 2 hours and then stirred for 6 hours. The stirring rate was 300 rpm and the reaction temperature was 80°C. After washing and drying, the adsorbent composite organic metal framework material was obtained. The molar ratio of zinc sulfate, N,N-dimethylacetamide and meso-tetra(4-carboxyphenyl)porphine was 9:5:1.

[0063] (3) 1,3-propanedisulfonic acid was dissolved in deionized water, and the adsorbent composite organic metal framework material was added at a mass ratio of 1,3-propanedisulfonic acid to the adsorbent composite organic metal framework material of 1:4.5. The mixture was reacted at a temperature of 70°C for 18 hours. After the reaction was completed, the mixture was centrifuged, and the supernatant was removed. After washing with water and acetone, the mixture was placed in a hydrochloric acid solution with a concentration of 0.5 mol / L and immersed for 48 hours to obtain the composite lithium extraction adsorbent.

[0064] Example 3

[0065] This embodiment provides a composite lithium extraction adsorbent, and the preparation method of the composite lithium extraction adsorbent is as follows:

[0066] (1) A manganese-based adsorbent was dispersed in ethanol under ultrasound assistance, 3-aminopropyltriethoxysilane was added at a mass ratio of 10:1 between the adsorbent and 3-aminopropyltriethoxysilane, and the mixture was reacted in a water bath at 40°C for 24 hours. The obtained product was washed with ethanol and dried in vacuo at 90°C to obtain an amino-modified adsorbent;

[0067] (2) The amino-modified adsorbent was placed in N,N-dimethylacetamide at a solid-liquid ratio of 1 g:12 mL and ultrasonically dispersed for 20 minutes to obtain a suspension. Zinc sulfate was added to the suspension and hydrothermally reacted with meso-tetra(4-carboxyphenyl)porphine, pyrazine, and polyvinylpyrrolidone for 9 hours, followed by stirring for 3 hours at a stirring rate of 300 rpm and a reaction temperature of 200°C. After washing and drying, the adsorbent composite organic metal framework material was obtained. The molar ratio of zinc sulfate, N,N-dimethylacetamide, and meso-tetra(4-carboxyphenyl)porphine was 6:2:1.

[0068] (3) 1,3-propanedisulfonic acid was dissolved in deionized water, and the adsorbent composite organic metal framework material was added at a mass ratio of 1,3-propanedisulfonic acid to the adsorbent composite organic metal framework material of 1:1.5, and the mixture was reacted at a temperature of 70°C for 18 hours. After the reaction was completed, the mixture was centrifuged, and the supernatant was removed. After washing with water and acetone, the mixture was placed in a hydrochloric acid solution with a concentration of 0.25 mol / L and soaked for 12 hours to obtain the composite lithium extraction adsorbent.

[0069] Example 4

[0070] The only difference between this embodiment and embodiment 1 is that the mass ratio of the manganese-based adsorbent to the amino modifier is 5:1, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0071] Example 5

[0072] The only difference between this embodiment and embodiment 1 is that the mass ratio of the manganese-based adsorbent to the amino modifier is 20:1, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0073] Example 6

[0074] The only difference between this example and Example 1 is that the molar ratio of zinc sulfate to tetrakis(4-carboxyphenyl)porphine is 10:1, and the other conditions and parameters are exactly the same as those in Example 1.

[0075] Example 7

[0076] The only difference between this embodiment and embodiment 1 is that the molar ratio of zinc sulfate to tetrakis(4-carboxyphenyl)porphine is 5:1, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0077] Example 8

[0078] The only difference between this embodiment and embodiment 1 is that the mass ratio of the sulfonic modifier and the adsorbent composite organic metal framework material is 1:1, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0079] Example 9

[0080] The only difference between this embodiment and embodiment 1 is that the mass ratio of the sulfonic modifier and the adsorbent composite organic metal framework material is 1:5, and the other conditions and parameters are exactly the same as those in embodiment 1.

[0081] Comparative Example 1

[0082] The only difference between this comparative example and Example 1 is that the manganese-based adsorbent is not amino-modified, and the other conditions and parameters are exactly the same as those in Example 1.

[0083] Comparative Example 2

[0084] The only difference between this comparative example and Example 1 is that the manganese-based adsorbent and the organic framework material are not compounded, and the other conditions and parameters are exactly the same as those in Example 1.

[0085] Comparative Example 3

[0086] The only difference between this comparative example and Example 1 is that no sulfonic group modification is performed, and other conditions and parameters are exactly the same as those in Example 1.

[0087] Performance testing:

[0088] The adsorbent obtained in the examples and comparative examples was mixed with PVDF and N-methylpyrrolidone in a mass ratio of 100:5:150 and granulated. The adsorbent particle size was 1.5 mm. +Lithium was extracted from brine with a concentration of 0.5 g / L, and the test results are shown in Table 1. Atomic absorption spectrophotometry was used to determine the lithium ion content in the solution before and after adsorption, and the adsorption capacity q was calculated. The calculation formula is: q = (C1V1-C2V2) / m. C1 and C2 are the mass concentrations of lithium ions in the solution before and after adsorption (mg / L), V1 and V2 are the volumes of the solution before and after adsorption (L), and m is the mass of the adsorbent (g). The lithium recovery rate is calculated by the following formula: η = ((C1-C2) / C1) × 100%, where C1 is the concentration of lithium in the brine before adsorption, and C2 is the concentration of lithium in the brine after adsorption. The manganese dissolution rate is calculated by the following formula: L Mn =ρ Mn V / m, where ρ Mn is the average mass concentration of manganese ions in the lithium-rich solution (g / L); V is the volume of the lithium-rich solution (L); and m is the mass of the adsorbent (g).

[0089] Table 1

[0090] As can be seen from Table 1, from Examples 1-3, the adsorption capacity of the composite lithium extraction adsorbent disclosed in the present invention can reach more than 16.88 mg / g, the lithium ion recovery rate can reach more than 93.5%, the dissolution loss rate can reach less than 0.0009%, and the adsorption efficiency maintained after 10 cycles can reach more than 94.06%.

[0091] By comparing Example 1 with Examples 4-5, it can be seen that in the preparation process of the composite lithium extraction adsorbent described in the present disclosure, the mass ratio of the manganese-based adsorbent and the amino modifier will affect its performance. The mass ratio of the manganese-based adsorbent and the amino modifier is controlled at 10 to 15:1, and the performance of the composite lithium extraction adsorbent obtained is better. If the amount of the amino modifier added is too large, too many active sites will be covered and the adsorption capacity of the manganese-based adsorbent will be reduced. If the amount of the amino modifier added is too small, the stability of the combination of the manganese-based adsorbent and the metal-organic framework will be affected, and the dissolution loss of the composite adsorbent will be increased.

[0092] By comparison of Example 1 and Examples 6-7, it can be seen that in the preparation process of the composite lithium extraction adsorbent described in the present disclosure, the molar ratio of zinc salt and tetrakis(4-carboxyphenyl)porphine will affect its performance. The molar ratio of zinc salt and tetrakis(4-carboxyphenyl)porphine is controlled at 6 to 9:1, and the performance of the composite lithium extraction adsorbent obtained is better. If the amount of zinc salt added is too large or the amount of tetrakis(4-carboxyphenyl)porphine added is too large, the mismatch between the metal ion donor and the organic ligand will cause incomplete reaction, resulting in the manganese-based adsorbent cannot be evenly loaded on the metal-organic framework material, and ultimately resulting in a decrease in the adsorption performance of the formed composite adsorbent.

[0093] By comparing Example 1 and Examples 8-9, it can be seen that in the preparation process of the composite lithium extraction adsorbent described in the present disclosure, the mass ratio of the sulfonyl modifier and the adsorbent composite organic metal framework material will affect its performance. The mass ratio of the sulfonyl modifier and the adsorbent composite organic metal framework material is controlled at 1:1.5~4.5, and the performance of the composite lithium extraction adsorbent is better. If the amount of the sulfonyl modifier added is too large, the effective adsorption surface area of ​​the adsorbent will be reduced. If the amount of the sulfonyl modifier added is too small, the wettability of the adsorbent will be reduced, resulting in a decrease in lithium adsorption performance.

[0094] By comparison between Example 1 and Comparative Example 1, it can be seen that after the modification of the manganese-based adsorbent by grafting amino groups, the present invention is conducive to the preferential adsorption of meso-tetrakis(4-carboxyphenyl)porphine in the organic ligand during the subsequent in situ generation of an organic metal framework on its surface, so that the metal organic framework grows uniformly on the surface of the adsorbent and the binding is more stable.

[0095] From the comparison between Example 1 and Comparative Example 2, it can be seen that the present disclosure fixes the manganese adsorbent inside the metal organic framework with high water stability to reduce the dissolution loss of manganese; on the other hand, the two-dimensional metal organic framework material has a high porosity with a pore size of 0.78-0.81nm, which is between Li + (0.764nm) and Mg 2+ (0.824nm), which is beneficial to improving the lithium ion selectivity of the composite adsorption material.

[0096] By comparing Example 1 and Comparative Example 3, it can be seen that the modification of the sulfonic acid groups grafted on the metal organic framework disclosed in the present invention can make it super hydrophilic, thereby improving the adsorption capacity of the adsorbent, and the metal organic framework material structure is relatively stable, avoiding the instability problem caused by the dissolution loss of the hydrophilic polymer during use of the adsorbent formed by currently commonly used hydrophilic polymers, such as sodium alginate or polysaccharides, which are coated with ion sieves.

Claims

1. A preparation method of a composite lithium extraction adsorbent, comprising the following steps: (1) Mix a manganese-based adsorbent, a first solvent, and an amino modifier, and obtain an amino-modified adsorbent through a one-step reaction; (2) Mix the amino-modified adsorbent, a zinc salt, meso-tetrakis(4-carboxyphenyl)porphine, pyrazine, N,N-dimethylacetamide, and a second solvent, and obtain an adsorbent composite metal-organic framework material through a two-step reaction; (3) Mix a sulfo modifier, the adsorbent composite metal-organic framework material, and a third solvent, and obtain a hydrophilic lithium extraction adsorbent through a three-step reaction, and obtain the composite lithium extraction adsorbent through acid leaching treatment.

2. The preparation method according to claim 1, wherein, The first solvent in step (1) includes ethanol.

3. The preparation method according to claim 1 or 2, wherein, The amino modifier includes 3-aminopropyltriethoxysilane.

4. The preparation method according to any one of claims 1-3, wherein, The mass ratio of the manganese-based adsorbent to the amino modifier is (10-15):

1.

5. The preparation method according to any one of claims 1-4, wherein, The one-step reaction in step (1) includes a water bath reaction; Optionally, the temperature of the one-step reaction is 40-50°C; Optionally, the time of the one-step reaction is 12-24 h.

6. The preparation method according to any one of claims 1-5, wherein, The zinc salt in step (2) includes any one or a combination of at least two of zinc nitrate, zinc sulfate, or zinc chloride.

7. The preparation method according to any one of claims 1-6, wherein, The meso-tetrakis(4-carboxyphenyl)porphine includes meso-tetrakis(4-carboxyphenyl)porphine.

8. The preparation method according to any one of claims 1 to 7, wherein, The mass-volume ratio of the amino-modified adsorbent to N,N-dimethylacetamide is 1:(1-3) g / mL.

9. The preparation method according to any one of claims 1-8, wherein, The second solvent includes polyvinylpyrrolidone.

10. The preparation method according to any one of claims 1-9, wherein, The molar ratio of the zinc salt, N,N-dimethylacetamide, and meso-tetrakis(4-carboxyphenyl)porphine is (6-9):(2-5):

1.

11. The preparation method according to any one of claims 1 to 10, wherein, The two-step reaction in step (2) includes stirring after hydrothermal reaction; Optionally, the temperature of the hydrothermal reaction is 80-200°C; Optionally, the time of the hydrothermal reaction is 2-9 h; Optionally, the stirring speed is 200-400 rpm; Optionally, the stirring time is 3-6 h.

12. The preparation method according to any one of claims 1-11, wherein, The sulfo modifier in step (3) includes 1,3-propanedisulfonic acid; Optionally, the third solvent includes deionized water; Optionally, the mass ratio of the sulfo modifier to the adsorbent composite metal-organic framework material is 1:(1.5-4.5).

13. The preparation method according to any one of claims 1-12, wherein, The temperature of the three-step reaction in step (3) is 50-70°C; Optionally, the time of the three-step reaction is 18-24 h; Optionally, centrifugation and washing treatments are performed after the three-step reaction; Optionally, the detergent for the washing treatment includes water and acetone.

14. The preparation method according to any one of claims 1-13, wherein, The acid solution for the acid leaching treatment in step (3) includes hydrochloric acid and / or sulfuric acid; Optionally, the concentration of the acid solution is 0.25-0.5 mol / L; Optionally, the time of the acid leaching treatment is 12-48 h.

15. A composite lithium extraction adsorbent prepared by the method according to any one of claims 1-14.

16. An application of the composite lithium extraction adsorbent according to claim 15 in extracting lithium from salt lakes.

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