A composite lithium extraction adsorbent, a preparation method and application thereof

Abstract

The present disclosure provides a composite lithium extraction adsorbent and a preparation method and application thereof, the preparation method comprising the following steps: (1) mixing a manganese-based adsorbent, a first solvent and an amino modifier to obtain an amino-modified adsorbent through one-step reaction; (2) mixing the amino-modified adsorbent, a zinc salt, a tetrakis(4-carboxyphenyl) porphyrin, a pyrazine, N,N-dimethylacetamide and a second solvent to obtain an adsorbent composite metal-organic framework material through two-step reaction; (3) mixing a sulfo modifier, the adsorbent composite metal-organic framework material and a third solvent to obtain a hydrophilic lithium extraction adsorbent through three-step reaction, and the lithium extraction adsorbent is obtained through acid leaching treatment. The method disclosed in the present disclosure can prepare a composite lithium extraction adsorbent with low solution loss rate and high adsorption selectivity and permeation rate.

Description

TECHNICAL FIELD

[0001] The present disclosure 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

[0002] Lithium and lithium compounds are important strategic resources and are widely used in energy, aerospace, alloy materials, ceramics, construction, chemical industry and other industries. In nature, lithium resources mainly exist in lithium ore, salt lake brine and seawater, etc. Nearly 80% of liquid lithium resources in China are distributed in salt lakes in Qinghai Province and Tibet Autonomous Region. However, due to the natural disadvantage of high magnesium-lithium ratio of salt lakes in China, the lithium extraction technology applied to lithium ore in domestic commercial application is still problematic in terms of low lithium content and purity when applied to salt lake lithium extraction. Therefore, the research on the extraction of lithium from salt lake brine has great strategic significance for the development and utilization of lithium resources. At present, the main methods for lithium extraction from salt lakes include precipitation method, solvent extraction method, evaporation crystallization method, calcination leaching method, salting-out method, carbonization method, electrodialysis method, molten salt electrolysis method, and adsorption method, etc.

[0003] Among them, the adsorption method has the characteristics of simple process, environmental friendliness and low cost, and has become one of the most promising methods for lithium extraction from salt lake brine in China. At present, ion sieve adsorbents are mainly used for lithium extraction from salt lake brine, including manganese-based lithium ion sieve, aluminum-based lithium ion sieve and titanium-based lithium ion sieve, etc.

[0004] CN108543521A discloses a fiber adsorbent for lithium extraction from salt lake brine and a preparation method thereof. The lithium-manganese composite oxide is obtained by preparing a ceramic fiber with a loose inner core, graphitizing the inner core, adsorbing lithium source and manganese source, and calcining. The lithium-manganese composite oxide is in the form of fibers in the inner core of the ceramic fiber, and lithium is eluted by acid washing.

[0005] CN108636341A discloses a molding method of lithium extraction adsorbent. Titanium-based lithium ion sieve or manganese-based lithium ion sieve is used as adsorbent raw powder, a polymer is dissolved in an organic solvent to prepare a binder, and the adsorbent raw powder is formed into a ball by a rotary molding method.

[0006] The above-mentioned scheme has high lithium ion theoretical adsorption capacity of manganese adsorbent, but has poor permeability and high dissolution loss rate, which leads to sharp reduction of adsorption capacity after multiple uses. SUMMARY

[0007] 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.

[0008] The purpose of the present disclosure is to provide a composite lithium extraction adsorbent and a preparation method and application thereof. The method disclosed in the present disclosure can prepare a composite lithium extraction adsorbent with low dissolution loss rate and high adsorption selectivity and permeability.

[0009] To achieve this purpose, the present disclosure adopts the following technical solutions:

[0010] In a first aspect, the present disclosure provides a preparation method of a composite lithium-adsorbing adsorbent, comprising the following steps:

[0011] (1) mixing a manganese-based adsorbent, a first solvent and an amino-modifying agent to obtain an amino-modified adsorbent through one-step reaction;

[0012] (2) mixing the amino-modified adsorbent, a zinc salt, tetrakis(4-carboxyphenyl) porphyrin, pyrazine, N,N-dimethylacetamide and a second solvent to obtain an adsorbent composite metal-organic framework material through two-step reaction;

[0013] (3) mixing a sulfonic-modifying agent, the adsorbent composite metal-organic framework material and a third solvent to obtain a hydrophilic lithium-adsorbing adsorbent through three-step reaction, and treating the adsorbent through acid immersion to obtain the composite lithium-adsorbing adsorbent.

[0014] After the amino modification of the manganese-based adsorbent in the present disclosure, the amino group on the surface of the manganese-based adsorbent reacts with the carboxyl group on the ligand in the metal-organic framework (the zinc salt reacts with tetrakis(4-carboxyphenyl) porphyrin to generate Zn-MOF, which is a metal-organic framework), and is then fixed inside the metal-organic framework with high water stability, thereby reducing the loss of manganese. The two-dimensional metal-organic framework material prepared by the method of the present disclosure has high porosity, a pore size of 0.78-0.81 nm, which is between the hydration ion radii of Li + (0.764 nm) and Mg 2+ (0.824 nm), which is conducive to improving the lithium ion selectivity of the composite adsorbent material. The modification of the sulfonic acid group grafted on the metal-organic framework can make it super-hydrophilic, thereby improving the adsorption capacity of the adsorbent.

[0015] In an embodiment, the first solvent in step (1) comprises ethanol.

[0016] In an embodiment, the amino-modifying agent comprises 3-aminopropyltriethoxysilane.

[0017] In an embodiment, the mass ratio of the manganese-based adsorbent to the amino-modifying agent is (10-15):1, for example, 10:1, 11:1, 12:1, 14:1 or 15:1, etc.

[0018] In an embodiment, the one-step reaction in step (1) comprises water bath reaction.

[0019] In an 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, etc.

[0020] In an embodiment, the one-step reaction is performed for 12-24 hours, for example, 12 hours, 15 hours, 18 hours, 20 hours, or 24 hours, etc.

[0021] After the modification of the manganese-based adsorbent by grafting amino groups, the amino groups on the manganese-based adsorbent can undergo acylation reaction with the carboxyl groups on meso-tetra(4-carboxyphenyl) porphyrin, which is conducive to the preferential adsorption of meso-tetra(4-carboxyphenyl) porphyrin in the organic ligand during the subsequent in-situ generation of metal-organic frameworks on its surface, so that the metal-organic frameworks grow uniformly on the surface of the adsorbent and are more stable.

[0022] In an embodiment, the zinc salt in step (2) includes any one or a combination of at least two of zinc nitrate, zinc sulfate, or zinc chloride.

[0023] In an embodiment, the tetra(4-carboxyphenyl) porphyrin includes meso-tetra(4-carboxyphenyl) porphyrin.

[0024] In an embodiment, the mass-to-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, etc.

[0025] In an embodiment, the second solvent includes polyvinylpyrrolidone.

[0026] In an embodiment, the molar ratio of the zinc salt, N,N-dimethylacetamide, and tetra(4-carboxyphenyl) porphyrin is (6-9):(2-5):1, for example, 6:2:1, 7:3:1, 8:2:1, 9:5:1, or 8:4:1, etc.

[0027] In an embodiment, the two-step reaction in step (2) includes stirring after the hydrothermal reaction.

[0028] In an embodiment, the temperature of the hydrothermal reaction is 80-200°C, for example, 80°C, 100°C, 120°C, 150°C, or 200°C, etc.

[0029] In an embodiment, the time of the hydrothermal reaction is 2-9 hours, for example, 2 hours, 4 hours, 5 hours, 8 hours, or 9 hours, etc.

[0030] In an embodiment, the stirring speed is 200-400 rpm, for example, 200 rpm, 250 rpm, 300 rpm, 350 rpm, or 400 rpm, etc.

[0031] In an embodiment, the stirring time is 3-6 hours, for example, 3 hours, 3.5 hours, 4 hours, 5 hours, or 6 hours, etc.

[0032] In an embodiment, the sulfonic modifier in step (3) comprises 1,3-propanedisulfonic acid.

[0033] In an embodiment, the third solvent comprises deionized water.

[0034] In an embodiment, the mass ratio of the sulfonic modifier to the adsorbent composite metal-organic framework is 1: (1.5-4.5), for example, 1:1.5, 1:2, 1:3, 1:4, or 1:4.5, etc.

[0035] In an 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, etc.

[0036] In an embodiment, the time of the three-step reaction is 18-24 hours, for example, 18 hours, 20 hours, 22 hours, 23 hours, or 24 hours, etc.

[0037] In an embodiment, the three-step reaction is followed by centrifugation and washing treatment.

[0038] In an embodiment, the washing agent for the washing treatment comprises water and acetone.

[0039] In an embodiment, the acid solution for the acid leaching treatment in step (3) comprises hydrochloric acid and / or sulfuric acid.

[0040] In an embodiment, the concentration of the acid solution is 0.25-0.5 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, etc.

[0041] In an embodiment, the time of the acid leaching treatment is 12-48 hours, for example, 12 hours, 16 hours, 18 hours, 20 hours, 24 hours, or 48 hours, etc.

[0042] The time of the acid leaching treatment affects the performance of the adsorbent. If the time is too short, the leaching of lithium ions is insufficient, and if the time is too long, the adsorbent is excessively acidized, leading to Mn loss.

[0043] In a second aspect, the present disclosure provides a composite lithium-extraction adsorbent prepared by the method of the first aspect.

[0044] In a third aspect, the present disclosure provides an application of the composite lithium-extraction adsorbent of the second aspect, wherein the composite lithium-extraction adsorbent is used for lithium extraction from salt lakes.

[0045] Compared with the prior art, the present disclosure has the following beneficial effects:

[0046] (1) The present disclosure prepares a metal organic framework with high water stability. After the manganese-based adsorbent is grafted and modified by amino groups, the amino groups on the surface of the metal organic framework undergo acylation reaction with the carboxyl groups on the metal organic framework, and the manganese-based adsorbent is then fixed inside the metal organic framework. The present disclosure fixes the manganese-based adsorbent inside the metal organic framework, which not only reduces the loss of manganese, but also improves the selectivity of the composite adsorbent for lithium ions.

[0047] (2) The modification of the sulfonic acid groups grafted on the metal organic framework can make the metal organic framework have super hydrophilicity, improve the adsorption capacity of the adsorbent, and the structure of the metal organic framework material is relatively stable, avoiding the instability problem of the adsorbent formed by coating ion sieves with commonly used hydrophilic polymers such as sodium alginate or polysaccharides during use due to the dissolution loss of the hydrophilic polymers.

[0048] (3) The adsorption capacity of the composite lithium extraction adsorbent described in the present disclosure can reach 16.88 mg / g or more, the lithium ion recovery rate can reach 93.5% or more, the dissolution loss rate can reach 0.0009% or less, and the adsorption efficiency maintained after 10 cycles can reach 94.06% or more.

[0049] Other aspects can be apparent after reading and understanding the detailed description. DETAILED DESCRIPTION

[0050] The technical solutions of the present disclosure will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only to help understand the present disclosure and should not be regarded as specific limitations on the present disclosure.

[0051] The manganese-based adsorbent described in the examples and comparative examples of the present disclosure is prepared by the following method:

[0052] LiOH and Mn2O3 are mixed uniformly at a molar ratio of 1.05:1, and then calcined at a temperature of 550°C for 12h to obtain the manganese-based adsorbent.

[0053] Example 1

[0054] The present embodiment provides a composite lithium extraction adsorbent, and the preparation method of the composite lithium extraction adsorbent is as follows:

[0055] (1) The manganese-based adsorbent is dispersed in ethanol under ultrasonic assistance, 3-aminopropyl triethoxysilane is added according to a mass ratio of the adsorbent to 3-aminopropyl triethoxysilane of 12:1, and then water bath reaction is carried out at a temperature of 45°C for 18h. The obtained product is washed with ethanol and vacuum dried at a temperature of 90°C to obtain an amino-modified adsorbent.

[0056] (2) The amino-modified adsorbent was dispersed in N,N-dimethylacetamide under ultrasonic assistance at a solid-liquid ratio of 1 g:2 mL to obtain a suspension, zinc sulfate, meso-tetra(4-carboxyphenyl) porphyrin, pyrazine, and polyvinylpyrrolidone were added to the suspension, and a hydrothermal reaction was performed for 6 h, followed by stirring for 4 h at a stirring rate of 300 rpm and a reaction temperature of 130 °C. After washing, the adsorbent composite metal-organic framework material was obtained by drying. The molar ratio of zinc sulfate, N,N-dimethylacetamide, and meso-tetra(4-carboxyphenyl) porphyrin was 7:4:1.

[0057] (3) 1,3-propanedisulfonic acid was dissolved in deionized water, and the adsorbent composite metal-organic framework material was added at a mass ratio of 1,3-propanedisulfonic acid to the adsorbent composite metal-organic framework material of 1:3. The mixture was reacted at a temperature of 60 °C for 21 h. After the reaction was completed, the mixture was centrifuged, and then the supernatant was removed. After washing with water and acetone, the mixture was immersed in a hydrochloric acid solution with a concentration of 0.35 mol / L for 24 h to obtain the composite lithium extraction adsorbent.

[0058] Example 2

[0059] The present embodiment provides a composite lithium extraction adsorbent, and a preparation method of the composite lithium extraction adsorbent is as follows:

[0060] (1) The manganese-based adsorbent was dispersed in ethanol under ultrasonic assistance, and 3-aminopropyltriethoxysilane was added at a mass ratio of the adsorbent to 3-aminopropyltriethoxysilane of 15:1. Then, a water bath reaction was performed at a temperature of 50 °C for 12 h. After washing with ethanol, the obtained product was dried under vacuum at a temperature of 90 °C to obtain an amino-modified adsorbent.

[0061] (2) The amino-modified adsorbent was dispersed in N,N-dimethylacetamide under ultrasonic assistance at a solid-liquid ratio of 1 g:3 mL to obtain a suspension, zinc sulfate, meso-tetra(4-carboxyphenyl) porphyrin, pyrazine, and polyvinylpyrrolidone were added to the suspension, and a hydrothermal reaction was performed for 2 h, followed by stirring for 6 h at a stirring rate of 300 rpm and a reaction temperature of 80 °C. After washing, the adsorbent composite metal-organic framework material was obtained by drying. The molar ratio of zinc sulfate, N,N-dimethylacetamide, and meso-tetra(4-carboxyphenyl) porphyrin was 9:5:1.

[0062] (3) 1,3-propanedisulfonic acid is dissolved in deionized water, and the adsorbent composite metal-organic framework material is added according to a mass ratio of 1,3-propanedisulfonic acid to adsorbent composite metal-organic framework material of 1:4.5, and reacted at a temperature of 70°C for 18h. After the reaction is completed, the mixture is centrifuged, and then the supernatant is removed. After washing with water and acetone, it is soaked in a hydrochloric acid solution with a concentration of 0.5mol / L for 48h to obtain the composite lithium extraction adsorbent.

[0063] Example 3

[0064] This example provides a composite lithium extraction adsorbent, and a preparation method thereof is as follows:

[0065] (1) The manganese-based adsorbent is dispersed in ethanol under ultrasonic assistance, and 3-aminopropyltriethoxysilane is added according to a mass ratio of adsorbent to 3-aminopropyltriethoxysilane of 10:1. Then, a water bath reaction is performed at a temperature of 40°C for 24h. After washing the obtained product with ethanol and vacuum drying at a temperature of 90°C, an amino-modified adsorbent is obtained.

[0066] (2) The amino-modified adsorbent is placed in N,N-dimethylacetamide according to a solid-liquid ratio of 1g:12mL to obtain a suspension after ultrasonic dispersion for 20min. After hydrothermal reaction of zinc sulfate, meso-tetrakis(4-carboxyphenyl) porphyrin, pyrazine and polyvinylpyrrolidone for 9h, stirring is performed for 3h at a stirring rate of 300rpm and a reaction temperature of 200°C. After washing and drying, the adsorbent composite metal-organic framework material is obtained. The molar ratio of zinc sulfate, N,N-dimethylacetamide and meso-tetrakis(4-carboxyphenyl) porphyrin is 6:2:1.

[0067] (3) 1,3-propanedisulfonic acid is dissolved in deionized water, and the adsorbent composite metal-organic framework material is added according to a mass ratio of 1,3-propanedisulfonic acid to adsorbent composite metal-organic framework material of 1:1.5, and reacted at a temperature of 70°C for 18h. After the reaction is completed, the mixture is centrifuged, and then the supernatant is removed. After washing with water and acetone, it is soaked in a hydrochloric acid solution with a concentration of 0.25mol / L for 12h to obtain the composite lithium extraction adsorbent.

[0068] Example 4

[0069] This example is different from example 1 only in that the mass ratio of the manganese-based adsorbent to the amino-modifying agent is 5:1, and other conditions and parameters are completely the same as those of example 1.

[0070] Example 5

[0071] The embodiment differs from example 1 only in that the mass ratio of the manganese-based adsorbent and the amino-modifier is 20:1, and other conditions and parameters are exactly the same as example 1.

[0072] Example 6

[0073] The embodiment differs from example 1 only in that the molar ratio of zinc sulfate and tetra(4-carboxyphenyl)porphyrin is 10:1, and other conditions and parameters are exactly the same as example 1.

[0074] Example 7

[0075] The embodiment differs from example 1 only in that the molar ratio of zinc sulfate and tetra(4-carboxyphenyl)porphyrin is 5:1, and other conditions and parameters are exactly the same as example 1.

[0076] Example 8

[0077] The embodiment differs from example 1 only in that the mass ratio of the sulfonic-modifier and the adsorbent composite metal-organic framework material is 1:1, and other conditions and parameters are exactly the same as example 1.

[0078] Example 9

[0079] The embodiment differs from example 1 only in that the mass ratio of the sulfonic-modifier and the adsorbent composite metal-organic framework material is 1:5, and other conditions and parameters are exactly the same as example 1.

[0080] Comparative Example 1

[0081] The comparative example differs from example 1 only in that the manganese-based adsorbent is not subjected to amino modification, and other conditions and parameters are exactly the same as example 1.

[0082] Comparative Example 2

[0083] The comparative example differs from example 1 only in that the manganese-based adsorbent is not compounded with the organic framework material, and other conditions and parameters are exactly the same as example 1.

[0084] Comparative Example 3

[0085] The comparative example differs from example 1 only in that sulfonic modification is not performed, and other conditions and parameters are exactly the same as example 1.

[0086] Performance test:

[0087] The adsorbents obtained in the examples and comparative examples are mixed with PVDF and N-methylpyrrolidone in a mass ratio of 100:5:150, and then granulated, and the adsorbent particle size is 1.5 mm. The adsorbent is used for Li +The test results are shown in Table 1. The lithium ion content in the solution before and after adsorption was determined by atomic absorption spectrophotometry, and the adsorption capacity q was calculated. The calculation formula is: q = (C1V1-C2V2) / m. C1 and C2 are the lithium ion mass concentrations (mg / L) in the solution before and after adsorption, respectively, V1 and V2 are the solution volumes (L) before and after adsorption, respectively, and m is the adsorbent mass (g). The lithium recovery rate is calculated by the following formula: η = ((C1-C2) / C1) x 100%, wherein C1 is the lithium concentration in the brine before adsorption, and C2 is the lithium concentration in the brine after adsorption. The manganese dissolution loss rate is calculated by the following formula: L Mn = p Mn V / m, wherein p Mn is the average mass concentration of manganese ions in the lithium-rich liquid (g / L); V is the volume of the lithium-rich liquid (L); and m is the mass of the adsorbent (g).

[0088] Table 1

[0089] Adsorption capacity mg / g Lithium ion recovery rate Dissolution rate Adsorption efficiency maintained after 10 cycles Example 1 18.35 94.8 0.008 95.55 Example 2 17.32 93.5 0.009 94.23 Example 3 16.88 93.9 0.009 94.06 Example 4 13.47 91.1 0.03 90.5 Example 5 14.72 90.7 0.06 89.3 Example 6 15.03 91.8 0.04 92.1 Example 7 14.11 90.0 0.05 91.7 Example 8 13.97 89.5 0.03 88.1 Example 9 15.26 90.9 0.02 90.8 Comparative Example 1 11.87 88.5 0.12 85.87 Comparative Example 2 9.45 87.1 0.41 80.66 Comparative Example 3 10.67 88.2 0.28 86.52

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

[0091] As can be seen from the comparison between Example 1 and Examples 4-5, in the preparation process of the composite lithium extraction adsorbent of the present disclosure, the mass ratio of the manganese-based adsorbent and the amino modifier will affect its performance. If the mass ratio of the manganese-based adsorbent and the amino modifier is controlled at 10-15:1, the performance of the prepared composite lithium extraction adsorbent is better. If the addition amount of the amino modifier is too large, too many active sites will be covered, reducing the adsorption capacity of the manganese-based adsorbent. If the addition amount of the amino modifier is too small, the stability of the combination of the manganese-based adsorbent and the metal organic framework will be affected, increasing the dissolution loss of the composite adsorbent.

[0092] As can be seen from the comparison between Example 1 and Examples 6-7, in the preparation process of the composite lithium extraction adsorbent of the present disclosure, the molar ratio of the zinc salt and the tetrakis(4-carboxyphenyl) porphyrin will affect its performance. If the molar ratio of the zinc salt and the tetrakis(4-carboxyphenyl) porphyrin is controlled at 6-9:1, the performance of the prepared composite lithium extraction adsorbent is better. If the addition amount of the zinc salt or the addition amount of the tetrakis(4-carboxyphenyl) porphyrin is too large, the mismatch between the metal ion donor and the organic ligand will cause incomplete reaction, resulting in that the manganese-based adsorbent cannot be uniformly loaded on the metal organic framework material, and finally leading to the decline of the adsorption performance of the formed composite adsorbent.

[0093] From the comparison of 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 sulfonic modifier and the adsorbent composite metal-organic framework material will affect its performance. If the mass ratio of the sulfonic modifier and the adsorbent composite metal-organic framework material is controlled at 1:1.5-4.5, the performance of the composite lithium extraction adsorbent prepared is better. If the addition amount of the sulfonic modifier is too large, the effective adsorption surface area of the adsorbent will decrease, and if the addition amount of the sulfonic modifier is too small, the wettability of the adsorbent will decrease, resulting in a decrease in the lithium adsorption performance.

[0094] From the comparison of Example 1 and Comparative Example 1, it can be seen that after the amino group is grafted on the manganese-based adsorbent for modification in the present disclosure, it is beneficial to preferentially adsorb meso-tetrakis(4-carboxyphenyl) porphyrin in the organic ligand in the subsequent in-situ generation of the metal-organic framework on the surface thereof, so that the metal-organic framework grows uniformly on the surface of the adsorbent and is more stable.

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

[0096] From the comparison of Example 1 and Comparative Example 3, it can be seen that the modification of the sulfonic acid group grafted on the metal-organic framework in the present disclosure can make it have superhydrophilicity, improve the adsorption capacity of the adsorbent, and the metal-organic framework material has a relatively stable structure, avoiding the instability problem of the adsorbent formed by coating the ion sieve with the commonly used hydrophilic polymers such as sodium alginate or polysaccharide, etc. in the use process due to the dissolution loss of the hydrophilic polymer.

Claims

1. A method for preparing a composite lithium extraction adsorbent, comprising the following steps: (1) The manganese-based adsorbent, the first solvent and the amino modifier are mixed and reacted in one step to obtain the amino-modified adsorbent; (2) The amino-modified adsorbent, zinc salt, tetra(4-carboxyphenyl)porphyrin, pyrazine, N,N-dimethylacetamide and a second solvent are mixed and reacted in two steps to obtain an adsorbent composite organometallic framework material. (3) The sulfonyl modifier, the adsorbent composite organometallic framework material and the third solvent are mixed and reacted in three steps to obtain a hydrophilic lithium extraction adsorbent. After acid leaching treatment, the composite lithium extraction adsorbent is obtained. The manganese-based adsorbent is prepared by the following method: After mixing LiOH and Mn2O3 at a molar ratio of 1.05:1, the mixture was calcined at 550℃ for 12 hours to obtain a manganese-based adsorbent. The amino modifier includes 3-aminopropyltriethoxysilane, the sulfonyl modifier includes 1,3-propanedisulfonic acid, the mass ratio of the manganese-based adsorbent to the amino modifier is (10~15):1, the molar ratio of the zinc salt, N,N-dimethylacetamide, and tetrakis(4-carboxyphenyl)porphyrin is (6~9):(2~5):1, and the mass ratio of the sulfonyl modifier to the adsorbent composite organometallic framework material is 1:(1.5~4.5).

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

3. The preparation method according to claim 1, wherein, The one-step reaction in step (1) includes a water bath reaction.

4. The preparation method according to claim 1, wherein, The temperature of the first-step reaction is 40~50℃.

5. The preparation method according to claim 1, wherein, The reaction time for this step is 12-24 hours.

6. The preparation method according to claim 1, 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 claim 1, wherein, The tetra(4-carboxyphenyl)porphyrin includes meso-tetra(4-carboxyphenyl)porphyrin.

8. The preparation method according to claim 1, wherein, The second solvent includes polyvinylpyrrolidone.

9. The preparation method according to claim 1, wherein, The two-step reaction in step (2) includes a hydrothermal reaction followed by stirring.

10. The preparation method according to claim 9, wherein, The temperature of the hydrothermal reaction is 80~200℃.

11. The preparation method according to claim 9, wherein, The hydrothermal reaction takes 2 to 9 hours.

12. The preparation method according to claim 9, wherein, The stirring speed is 200~400 rpm.

13. The preparation method according to claim 9, wherein, The stirring time is 3-6 hours.

14. The preparation method according to claim 1, wherein, The third solvent includes deionized water.

15. The preparation method according to claim 1, wherein, The temperature of the three-step reaction in step (3) is 50~70℃.

16. The preparation method according to claim 1, wherein, The three-step reaction takes 18-24 hours.

17. The preparation method according to claim 1, wherein, The three-step reaction is followed by centrifugation and washing.

18. The preparation method according to claim 17, wherein, The detergent used in the washing process includes water and acetone.

19. The preparation method according to claim 1, wherein, The acid solution used in step (3) for acid leaching includes hydrochloric acid and / or sulfuric acid.

20. The preparation method according to claim 19, wherein, The concentration of the acid solution is 0.25~0.5mol / L.

21. The preparation method according to claim 1, wherein, The acid leaching treatment time is 12~48h.

22. A composite lithium extraction adsorbent prepared by the method according to any one of claims 1-21.

23. An application of the composite lithium extraction adsorbent as described in claim 22 for lithium extraction from salt lakes.