Aluminum-based lithium adsorbent, and preparation method and application thereof

Abstract

This invention belongs to the field of lithium adsorbent technology, and discloses an aluminum-based lithium adsorbent, its preparation method, and its application. The method involves mixing water-soluble lithium salt, aluminum salt, graphite analog, and an antibacterial agent to obtain a mixed solution. After pH adjustment, reaction, and filtration, an active powder is obtained. This powder is then mixed with a binder dissolved in a solvent, granulated, dried, and sieved to obtain the aluminum-based lithium adsorbent. In this aluminum-based lithium adsorbent, the sharp lamellar structure of the graphite analog surface can disrupt cell integrity, and the oxygen-containing functional groups release reactive oxygen species and free radicals to inhibit microbial growth and increase the mechanical strength of the adsorbent. The doped antibacterial agent interferes with cell metabolism, and the two work synergistically to enhance the antibacterial effect. This material inhibits bacteria through physicochemical means, is less likely to induce drug resistance, extends service life, reduces the risk of biocontamination, and improves adsorption capacity and efficiency.

Description

Technical Field

[0001] This invention belongs to the field of lithium adsorbent technology, and relates to an aluminum-based lithium adsorbent, its preparation method, and its application. Background Technology

[0002] Amid the global energy transition, the new energy industry is booming, and electric vehicles and energy storage systems are becoming increasingly widespread, leading to a sustained surge in demand for lithium resources. As a key strategic resource, lithium plays an irreplaceable role in numerous fields such as battery manufacturing, aerospace, and new energy, highlighting its strategic importance. Currently, lithium resource acquisition mainly relies on lithium extraction from ores; however, this method has many drawbacks. Ores are limited, and reserves are decreasing with continuous mining; the mining process is costly, requiring substantial capital investment at every stage from exploration and extraction to processing; simultaneously, mining activities impose a significant burden on the environment, disrupting the ecological balance and triggering a series of environmental problems. Therefore, exploring low-cost, sustainable lithium resource acquisition methods is urgently needed. Against this backdrop, salt lake brines, as an important source of lithium resources, are gradually coming into focus. Although the lithium-ion concentration in salt lake brines is generally low, high-purity lithium products can still be produced through a series of enrichment, separation, and purification processes.

[0003] Currently, there are various technologies for lithium extraction from salt lakes, including precipitation, extraction, calcination leaching, electrodialysis, membrane separation, and adsorption. Each method has its own characteristics and is suitable for different brine qualities and process requirements. Among them, adsorption has attracted much attention due to its advantages of simple operation and low cost. Its principle is based on the high specific surface area and porous structure of lithium adsorbents. These characteristics provide numerous attachment sites for lithium ions, enabling the adsorbent to efficiently adsorb lithium ions from the brine, thereby achieving lithium resource extraction.

[0004] However, adsorption methods also face serious challenges in practical applications. Natural salt lake brines contain algae and other microorganisms, which proliferate rapidly under suitable temperatures. The high specific surface area and porous structure of lithium adsorbents not only facilitate lithium ion adsorption but also make them ideal carriers for microbial attachment. Once microorganisms proliferate on the adsorbent surface, they severely contaminate the adsorbent, damaging its internal structure and causing a significant decrease in adsorption capacity. This not only affects the extraction efficiency of lithium resources but also adversely impacts the stable operation of subsequent processing technologies, reducing the reliability and economic efficiency of the entire salt lake lithium extraction system. For example, the method for removing algae from brine using a micro-electrolysis system proposed in Chinese patent application CN116177679A, while suitable for algae removal, suffers from cumbersome procedures and high costs, making large-scale application difficult. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an aluminum-based lithium adsorbent, its preparation method, and its application, thereby solving the technical problem in the prior art where lithium adsorbents are easily contaminated by microorganisms that proliferate in brine during lithium extraction from salt lakes, resulting in a decrease in adsorption capacity and affecting extraction efficiency and subsequent processes.

[0006] This invention is achieved through the following technical solution: A method for preparing an aluminum-based lithium adsorbent includes the following steps: S1: Mix water-soluble lithium salt, water-soluble aluminum salt and antibacterial agent to prepare a mixed solution; then stir and heat, adjust the pH of the mixed solution to neutral, continue stirring the reaction, and filter, dry, pulverize and sieve the product to obtain lithium adsorbent active powder. S2: Dissolve the binder in a solvent, add the lithium adsorbent active powder, mix evenly, granulate, dry and sieve to obtain the aluminum-based lithium adsorbent. In the process of preparing the mixture in S1, or in the granulation process described in S2, a graphite analogue is added.

[0007] Preferably, the graphite analogue is at least one of graphene, graphene oxide, carbon nanotubes, Ketjen black, acetylene black, carbon fiber, activated carbon, and furnace black; the antibacterial agent includes at least one of elemental copper, elemental gallium, elemental silver, copper-containing compounds, gallium-containing compounds, and silver-containing compounds.

[0008] Preferably, the copper-containing compound includes at least one of copper chloride and copper sulfate; the gallium-containing compound includes gallium nitrate nonahydrate; and the silver-containing compound includes silver nitrate.

[0009] Preferably, the concentration of aluminum ions in the mixture is 1.2~1.5 mol / L, and the molar ratio of aluminum ions in the water-soluble aluminum salt to lithium ions in the water-soluble lithium salt is 1:(1~3).

[0010] Preferably, the particle size of the graphite analog is 1 nm to 1000 nm; the ratio of the amount of graphite analog added (g) to the amount of aluminum ions in the water-soluble aluminum salt (mol) is (1.2~4):1.

[0011] Preferably, the molar ratio of the antibacterial agent to aluminum ions is (1~50):1000.

[0012] Preferably, in step S1, the drying temperature is 60~80℃ and the time is 8~12h; the particle size of the powder obtained after pulverization is not greater than 200 mesh.

[0013] Preferably, the mass ratio of the adhesive to the lithium adsorbent active powder is (0.05~0.2):1.

[0014] An aluminum-based lithium adsorbent is prepared by the method described above.

[0015] The above-mentioned aluminum-based lithium adsorbent is used in lithium extraction from salt lakes.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: This invention discloses a method for preparing an aluminum-based lithium adsorbent. This method effectively solves the problem of decreased adsorption capacity caused by microbial contamination in lithium extraction from salt lakes by introducing graphite analogs and antibacterial agents during the preparation process. The sharp, lamellar structure of the graphite analogs can effectively disrupt the integrity of microbial cells, and their rich oxygen-containing functional groups can release reactive oxygen species and free radicals, inducing oxidative stress in microorganisms, inhibiting their growth and metabolism, and also increasing the mechanical strength of the adsorbent. The antibacterial agent further interferes with the normal metabolic functions of microorganisms. The two work synergistically through physical and chemical antibacterial mechanisms, avoiding the development of drug resistance in microorganisms. Thanks to the synergistic effect of multiple antibacterial mechanisms, this adsorbent maintains a low level of biocontamination during long-term operation, significantly improving adsorption capacity and efficiency, and ensuring extraction efficiency and the stability of subsequent processes.

[0017] Furthermore, the graphite analogue is at least one of graphene, graphene oxide, carbon nanotubes, Ketjen black, acetylene black, carbon fiber, activated carbon, and furnace black; the antibacterial agent includes at least one of elemental copper, elemental gallium, elemental silver, copper-containing compounds, gallium-containing compounds, and silver-containing compounds. The specific types of graphite analogues and antibacterial agents are limited here to ensure that the material has excellent specific surface area and broad-spectrum antibacterial properties, maximizing the synergistic effect.

[0018] Furthermore, in the mixture, the concentration of aluminum ions is 1.2~1.5 mol / L, and the molar ratio of aluminum ions in the water-soluble aluminum salt to lithium ions in the water-soluble lithium salt is 1:(1~3). Here, the aluminum-lithium molar ratio and aluminum ion concentration are optimized to balance the adsorption capacity and structural stability, avoid co-precipitation of impurities, and improve selectivity.

[0019] Furthermore, the particle size of the graphite analog is 1 nm to 1000 nm; the mass ratio of the graphite analog to the amount of aluminum ions in the water-soluble aluminum salt is (1.2~4) g: 1 mol. Here, the particle size and dosage of the graphite analog are controlled to prevent agglomeration and blockage of the pores, ensure uniform dispersion in the matrix, and maintain high permeability.

[0020] Furthermore, the molar ratio of the antibacterial agent to aluminum ions is (1~50):1000. Here, the optimal doping ratio of the antibacterial agent is set to ensure efficient sterilization while avoiding excessive metal occupying active sites or causing environmental pollution.

[0021] Furthermore, in step S1, the drying temperature is 60~80℃ and the time is 8~12h; the particle size of the lithium adsorbent active powder is no greater than 200 mesh. The drying temperature and particle size are specified here to prevent high temperature from damaging the crystal structure and to ensure that the powder particle size is suitable for subsequent molding and ion diffusion.

[0022] Furthermore, the mass ratio of the binder to the lithium adsorbent active powder is (0.05~0.2):1. This optimized ratio of binder to lithium adsorbent active powder balances particle mechanical strength and porosity, prevents micropore blockage during the molding process, and ensures adsorption kinetic performance. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The image shows the appearance of the lithium adsorbent prepared in Example 1. Detailed Implementation

[0025] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0026] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0027] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0028] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0029] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0030] This invention provides a method for preparing an aluminum-based lithium adsorbent, comprising the following steps: S1: A mixture of water-soluble lithium salt, water-soluble aluminum salt and antibacterial agent is prepared; optionally, graphite-like material is added to the mixture, and then the mixture is stirred and heated. The pH of the mixture is adjusted to neutral by an alkaline solution, and the reaction is continuously stirred. After the reaction is completed, the product is filtered, dried, pulverized and sieved to obtain lithium adsorbent active powder. The water-soluble lithium salt is at least one of lithium chloride, lithium bromide, lithium carbonate, lithium nitrate, and lithium sulfate. The water-soluble aluminum salt is at least one of aluminum chloride, aluminum chloride hydrate, aluminum nitrate, aluminum nitrate hydrate, aluminum bromide, aluminum bromide hydrate, aluminum sulfate, aluminum sulfate hydrate, polyaluminum chloride, aluminum carbonate, and potassium aluminum sulfate dodecahydrate. The alkaline solution is at least one of sodium hydroxide solution, potassium hydroxide solution, lithium hydroxide solution, and ammonia water; The graphite analogue is at least one of graphene, graphene oxide, carbon nanotubes, Ketjen black, acetylene black, carbon fiber, activated carbon, and furnace black. The antibacterial agent includes at least one of copper, gallium, and silver; specifically, it may include at least one of the elemental form, copper-containing compound, gallium-containing compound, and silver-containing compound.

[0031] The copper-containing compound includes at least one of copper chloride and copper sulfate; The gallium-containing compound includes gallium nitrate nonahydrate; The silver-containing compound includes silver nitrate; the elemental silver can be nano-silver. In addition, the concentration of aluminum ions in the mixture is 1.2~1.5 mol / L, and 1.2 mol / L, 1.4 mol / L and 1.5 mol / L can be selected to ensure that the solid content of the suspension obtained after the reaction is appropriate and the doping is relatively uniform, while also taking into account the preparation efficiency. The molar ratio of aluminum ions in the water-soluble aluminum salt to lithium ions in the water-soluble lithium salt is 1:(1~3), and can be selected as 1:1, 1:2 and 1:3, which can ensure the effective insertion rate of lithium.

[0032] The alkaline solution has a hydroxide molar concentration of 5-12 mol / L. The alkaline solution is added dropwise to the mixture over a period of 30-60 minutes. This maintains a reasonable precipitation rate for lithium adsorbents and other active materials, thereby improving the uniformity of doping. During this step, the pH of the mixture is adjusted to 6-7.

[0033] The graphite analogue has a particle size of 1nm~1000nm, which makes the doping more uniform; the ratio of its added mass to the amount of aluminum ions is (1.2~4)g:1mol, which allows the adsorbent to have both anti-pollution properties and lithium adsorption performance.

[0034] The graphite analogues are included, but are not limited to, being added at any stage of the synthesis of aluminum-based lithium adsorbents, such as in step S1 or in the granulation stage of step S2.

[0035] The molar ratio of the antibacterial agent to aluminum ions is (1~50):1000, and can be selected as 1:1000, 5:1000, 10:1000, 20:1000 and 50:1000, which can make the adsorbent take into account both anti-pollution properties and lithium adsorption performance.

[0036] The reaction process involves raising the temperature of the mixed solution to 60-80℃, adding the alkaline solution dropwise, and then keeping it at this temperature for 3-8 hours to ensure a complete reaction.

[0037] In this step, after filtration, the obtained filter cake is dried at a temperature of 60~80℃ for 8~12 hours.

[0038] In this step, after crushing and sieving, the particle size of the lithium adsorbent active powder obtained is no greater than 200 mesh, which makes the powder easier to form.

[0039] S2: Dissolve the binder in a solvent and add the lithium adsorbent active powder. After mixing evenly, granulate, dry and sieve. Optionally, graphite-based substances are added during the granulation process to obtain the aluminum-based lithium adsorbent.

[0040] The adhesive is at least one of polyvinyl chloride, chlorinated polyvinyl chloride, polystyrene, epoxy resin, polyvinylidene fluoride, polysulfone, polyethersulfone, polyacrylonitrile, polymethyl methacrylate, and cellulose acetate.

[0041] The solvent is at least one selected from N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, ethyl acetate, acetone, toluene, dichloromethane, dichloroethane, and dimethyl sulfoxide.

[0042] The mass ratio of the binder to the lithium adsorbent active powder is (0.05~0.2):1, which can be 0.05:1, 0.07:1, 0.1:1 and 0.2:1. This ratio allows the adsorbent to balance lithium adsorption performance and service life. The mass ratio of the solvent to the adhesive is (4~6):1, which can be 4:1, 5:1 and 6:1. This ratio allows the adhesive to fully dissolve or swell, thus ensuring the bonding effect.

[0043] The granulation method is extrusion granulation, including but not limited to basket extrusion granulation, planetary extrusion granulation, screw extrusion granulation, etc.

[0044] In this step, the drying temperature is 60~80℃ and the drying time is 8~12 hours, which allows the adsorbent to solidify and form under mild conditions, avoiding excessive moisture loss and damage to the lithium adsorption active body structure. In this step, the dried material is sieved to obtain an aluminum-based lithium adsorbent with a particle size distribution of 0.5~2mm. The adsorbent is short rod-shaped and has a porous structure.

[0045] In the aluminum-based lithium adsorbent prepared by this invention, the relative mass ratio of graphite analog to aluminum is (4~15):100, that is, the mass ratio of the graphite analog to the amount of aluminum ions in the water-soluble aluminum salt is (1.2~4) g:1 mol; the molar ratio of the antibacterial agent to aluminum ions is (1~50):1000, and the corresponding mass ratio is approximately (0.2~20):100; the mass ratio of the binder to the active powder of the lithium adsorbent is (5~20):100, that is, (0.05~0.2):1.

[0046] The anti-biofouling principle of this invention is mainly based on the mechanism by which graphite analogs and antibacterial agents inhibit the growth of algae and other microorganisms. Graphite analogs have a sharp, lamellar structure on their surface. These lamellar structures disrupt the integrity of cell structures through physical contact stress, leading to cell rupture and death. Graphite analogs such as graphene oxide contain a large number of oxygen-containing functional groups on their surface. These groups react with cells, releasing reactive oxygen species and free radicals. These highly reactive substances can damage the cell structure and physiological functions of algae and other microorganisms, effectively inhibiting their growth. Simultaneously, graphite analogs can also increase the mechanical strength of lithium adsorbents, extending their lifespan. Furthermore, the doped antibacterial agents can interfere with cellular metabolic processes, further enhancing the antibacterial effect. Graphite analogs disrupt the cell structure of algae and other microorganisms, exposing the internal cell structure, allowing the antibacterial agents to function more effectively and strengthening the antibacterial effect. The synergistic effect of graphite analogs and antibacterial agents significantly improves the overall antifouling capability of the adsorbent.

[0047] Therefore, this invention endows lithium adsorbents with excellent broad-spectrum antibacterial capabilities by incorporating graphite analogs and antibacterial agents. The material's mechanism of action is physicochemical, making it less likely to induce drug resistance in algae and other microorganisms, thus significantly extending the adsorbent's lifespan. The synergistic effect of the graphite-based carbonaceous material and the antibacterial agent allows the adsorbent to maintain high performance while effectively inhibiting the attachment and reproduction of algae and other microorganisms on its surface, preventing pore blockage caused by biofilm formation, reducing the risk of biological pollution to water bodies, and exhibiting good environmental compatibility. Simultaneously, the doping of the antibacterial agent accelerates the lithium-ion mass transfer rate, thereby improving adsorption efficiency.

[0048] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0049] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0050] Example 1 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 107g of lithium chloride were weighed into a 5L three-necked reactor and dissolved in 1640mL of pure water. The aluminum concentration was determined to be 1.20mol / L. Then, 3.00g of graphene and 0.33g of copper chloride were added, ultrasonicated and mixed thoroughly, stirred and heated to 60℃. Sodium hydroxide solution (5mol / L) was added dropwise while stirring, and the addition was completed in one hour. The addition was considered complete when the pH of the final mixture was 6.02. The temperature was raised to 60℃ and maintained for 3 hours. After the reaction was completed, a wet filter cake was obtained by filtration. The wet filter cake was dried at 60℃ for 8 hours, crushed and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0051] Dissolve 5g of chlorinated polyvinyl chloride in 20mL of dichloroethane, sonicate and stir evenly, then mix with 100g of lithium adsorbent active powder, and then granulate using a basket extruder. Dry the resulting wet adsorbent at 60℃ for 8 hours, and screen to obtain aluminum-based lithium adsorbent with a particle size of 0.5-2mm.

[0052] The method for testing aluminum concentration in this invention is as follows: an excess and a known amount of ethylenediaminetetraacetic acid (EDTA) standard solution is added to an aluminum solution. After the complexation reaction is completed, the remaining EDTA is titrated with a standard solution of another metal ion (such as zinc), thereby indirectly calculating the aluminum content.

[0053] Example 2 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 214g of lithium chloride were weighed into a 5L three-necked reactor and dissolved in 1500mL of pure water. The aluminum concentration was determined to be 1.26mol / L. Then, 5.00g of graphene oxide and 1.35g of nano-silver were added, ultrasonicated and mixed thoroughly, stirred and heated to 70℃. While stirring, potassium hydroxide solution (7mol / L) was added dropwise until the pH of the final mixture reached 6.24, indicating the addition was complete. The temperature was raised to 70℃ and maintained for 5 hours. After the reaction was complete, a wet filter cake was obtained by filtration. The wet filter cake was dried at 70℃ for 10 hours, crushed and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0054] Dissolve 7g of polyvinylidene fluoride in 35mL of N,N-dimethylacetamide, sonicate and stir evenly, then mix with 100g of lithium adsorbent active powder, and then granulate using a screw extruder. Dry the resulting wet adsorbent at 70℃ for 10 hours, and screen to obtain a 0.5-2mm anti-pollution aluminum-based lithium adsorbent.

[0055] Example 3 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 107g of lithium chloride were weighed into a 5L three-necked reactor and dissolved in 1400mL of pure water. The aluminum concentration was determined to be 1.36mol / L. Then, 6.25g of carbon nanotubes and 4.25g of silver nitrate were added, ultrasonicated and mixed thoroughly. The mixture was then stirred and heated to 80℃. Ammonia water (20% by mass) was added dropwise while stirring, and the addition was completed in 40 minutes. The addition was considered complete when the pH of the final mixture was 6.41. The temperature was raised to 80℃ and maintained for 8 hours. After the reaction was completed, a wet filter cake was obtained by filtration. The wet filter cake was dried at 80℃ for 12 hours, crushed, and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0056] 10g of polyacrylonitrile was dissolved in 60mL of N,N-dimethylformamide, sonicated and stirred evenly, and then mixed with 100g of lithium adsorbent active powder. Granulation was then completed using a planetary extruder. The resulting wet adsorbent was dried at 80℃ for 12 hours, and a 0.5-1.3mm anti-pollution aluminum-based lithium adsorbent was obtained by screening.

[0057] Example 4 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 320g of lithium chloride were weighed into a 5L three-necked reactor and dissolved in 1300mL of pure water. The aluminum concentration was determined to be 1.37mol / L. Then, 7.51g of acetylene black and 24.43g of gallium nitrate nonahydrate were added, ultrasonicated and mixed thoroughly. The mixture was then stirred and heated to 80℃. Sodium hydroxide solution (8mol / L) was added dropwise while stirring, and the addition was completed in one hour. The addition was considered complete when the pH of the final mixture reached 6.54. The temperature was raised to 80℃ and maintained for 3 hours. After the reaction was complete, a wet filter cake was obtained by filtration. The wet filter cake was dried at 80℃ for 3 hours, crushed, and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0058] Dissolve 10g of polymethyl methacrylate in 50mL of dichloroethane, sonicate and stir until homogeneous, then mix with 100g of lithium adsorbent active powder, and then granulate using a basket extruder. Dry the resulting wet adsorbent at 80℃ for 3 hours, and screen to obtain a 0.5-2mm anti-pollution aluminum-based lithium adsorbent.

[0059] Example 5 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 320g of lithium chloride were weighed into a 5L three-necked reactor and dissolved in 1200mL of pure water. The aluminum concentration was determined to be 1.45mol / L. Then, 8.76g of carbon black and 19.97g of copper sulfate were added, ultrasonicated and mixed thoroughly. The mixture was then stirred and heated to 80℃. Sodium hydroxide solution (10mol / L) was added dropwise while stirring, and the addition was completed over 50 minutes. The addition was considered complete when the pH of the final mixture was 6.69. The temperature was raised to 80℃ and maintained for 3 hours. After the reaction was complete, a wet filter cake was obtained by filtration. The wet filter cake was dried at 80℃ for 3 hours, crushed, and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0060] Dissolve 20g of chlorinated polyvinyl chloride in 80mL of dichloroethane, sonicate and stir evenly, then mix with 100g of lithium adsorbent active powder obtained in the previous step, and then granulate using a basket extruder. Dry the obtained wet adsorbent at 80℃ for 3 hours, and screen to obtain a 0.5-2mm anti-pollution aluminum-based lithium adsorbent.

[0061] Example 6 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 320g of lithium chloride were weighed into a 5L three-necked reactor. After dissolving them in 1140mL of pure water, the aluminum concentration was determined to be 1.50mol / L. Then, 19.97g of copper sulfate was added, and the mixture was sonicated and thoroughly mixed. The mixture was then stirred and heated to 80℃. Sodium hydroxide solution (12mol / L) was added dropwise while stirring, completing the addition over one hour. The addition was considered complete when the pH of the final mixture reached 6.77. The temperature was then raised to 80℃ and maintained for 3 hours. After the reaction was complete, a wet filter cake was obtained. This wet filter cake was dried at 80℃ for 3 hours, crushed, and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0062] Dissolve 10g of chlorinated polyvinyl chloride in 50mL of dichloroethane, then add 10.01g of graphene, sonicate and stir evenly, then mix with 100g of lithium adsorbent active powder obtained in the previous step, and then granulate using a basket extruder. Dry the obtained wet adsorbent at 80℃ for 3 hours, and screen to obtain a 0.5-2mm anti-pollution aluminum-based lithium adsorbent.

[0063] Comparative Example 1 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 214g of lithium chloride were weighed into a 5L three-necked reactor and dissolved in 1400mL of pure water. The aluminum concentration was determined to be 1.32mol / L. The mixture was stirred and heated to 80℃, while adding sodium hydroxide solution (10mol / L) dropwise. The addition was completed within one hour, and the addition was considered complete when the pH of the final mixture reached 6.82. The temperature was then raised to 80℃ and maintained for 3 hours. After the reaction was complete, a wet filter cake was obtained by filtration. The wet filter cake was dried at 80℃ for 3 hours, crushed, and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0064] Dissolve 10g of chlorinated polyvinyl chloride in 50mL of dichloroethane, sonicate and stir evenly, then mix with 100g of lithium adsorbent active powder obtained in the previous step, and then granulate using a basket extruder. Dry the obtained wet adsorbent at 80℃ for 3 hours, and screen to obtain aluminum-based lithium adsorbent with a particle size distribution of 0.5~2mm.

[0065] No graphite analogs or antibacterial agents were added in this comparative example.

[0066] Comparative Example 2 A method for preparing an aluminum-based lithium adsorbent includes the following steps: 604g of aluminum trichloride hexahydrate and 107g of lithium chloride were weighed into a 5L three-necked reactor. After dissolving them in 1300mL of pure water, the aluminum concentration was determined to be 1.43mol / L. Then, 21.33g of copper chloride was added, and the mixture was ultrasonicated and thoroughly mixed. The mixture was then stirred and heated to 80℃. Ammonia solution (17% by mass) was added dropwise while stirring, completing the addition over one hour. The addition was considered complete when the pH of the final mixture reached 6.94. The temperature was raised to 80℃ and maintained for 3 hours. After the reaction was complete, a wet filter cake was obtained. The wet filter cake was dried at 80℃ for 3 hours, crushed, and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0067] Dissolve 10g of chlorinated polyvinyl chloride in 50mL of dichloroethane, sonicate and stir evenly, then mix with 100g of lithium adsorbent active powder obtained in the previous step, and then granulate using a basket extruder. Dry the obtained wet adsorbent at 80℃ for 3 hours, and screen to obtain aluminum-based lithium adsorbent with a particle size distribution of 0.5~2mm.

[0068] No graphite analogues were added in this comparative example.

[0069] Comparative Example 3 A method for preparing an aluminum-based lithium adsorbent includes the following steps: Weigh 604g of aluminum trichloride hexahydrate and 214g of lithium chloride into a 5L three-necked reactor, then add 1400mL of pure water to dissolve them. The aluminum concentration was then measured to be 1.32mol / L. Next, add 10.00g of furnace black, sonicate and mix thoroughly. Then, stir and heat to 80℃, adding sodium hydroxide solution (12mol / L) dropwise while stirring. The addition was completed within one hour, and was considered complete when the pH of the final mixture reached 6.58. The temperature was then raised to 80℃ and maintained for 3 hours. After the reaction was complete, a wet filter cake was obtained by filtration. The wet filter cake was dried at 80℃ for 3 hours, crushed, and sieved through a 200-mesh sieve to obtain lithium adsorbent active powder.

[0070] Dissolve 10g of polyethersulfone in 50mL of dichloroethane, sonicate and stir evenly, then mix with 100g of lithium adsorbent active powder obtained in the previous step, and then granulate using a basket extruder. Dry the obtained wet adsorbent at 80℃ for 3 hours, and screen to obtain aluminum-based lithium adsorbent with a particle size distribution of 0.5~2mm.

[0071] No antibacterial agent was added in this comparative example.

[0072] Figure 1 The image shows the appearance of the lithium adsorbent prepared in Example 1 of this invention. The other examples are similar and will not be shown. As can be seen from the image, the adsorbents prepared in this invention are mostly rod-shaped and are light gray in color due to the doping of graphene analogues.

[0073] Furthermore, the performance of the aluminum-based lithium adsorbent prepared in the embodiments of the present invention is verified through the following dynamic application experiments: 1. Experimental verification using brine Algal-containing brine: The content of each component in the brine is as follows: Li + 0.4 g / L, Na + 100 g / L, K + 14 g / L, Mg 2+ 11 g / L, Ca 2+ :0.4 g / L, B(III): 0.5 g / L, Cl - : 190 g / L, brine pH value 6.5-7.0, microbial biomass (10 5 ~10 7 (cells / mL), microorganisms such as halophilic algae and halophilic archaea.

[0074] Algae-free brine: Except for the absence of algae and other microorganisms, it is the same as the algae-containing brine mentioned above and is used for parallel experiments.

[0075] 2. Experimental Procedure a. Activation: Take 150g of the lithium adsorbent sample to be tested into a 500mL beaker and soak it in 300mL of pure water for 2 hours. Then, measure 60mL of the soaked lithium adsorbent into each beaker using a graduated cylinder and load them into two PVC (or glass) adsorption columns with an inner diameter of 22mm and a height of 300mm. Pass room temperature pure water through the column at a flow rate of 2.5 BV / h for 8 hours. BV refers to the adsorbent bed volume.

[0076] b. Adsorption: At room temperature, 16 BV of algal-containing brine and algal-free brine were passed through two parallel samples of each lithium adsorbent sample at a flow rate of 2 BV / h. After the adsorption process, the Li in the effluent mixture from each column was measured. + content.

[0077] c. Displacement: 2 BV of room temperature pure water is passed through the adsorbent at a flow rate of 10 BV / h.

[0078] d. Desorption: Pass 10 BV of room temperature pure water through the adsorbent at a flow rate of 4 BV / h.

[0079] Conduct 100 cycles of adsorption-desorption experiments.

[0080] 3. Calculate the adsorption capacity Adsorption capacity = (Lithium content of brine sample - Lithium content of the mixture after adsorption) * 16 Experimental verification The adsorption performance and attenuation performance test results of the aluminum-based lithium adsorbents prepared in Examples 1-6 and Comparative Examples 1-3 of this invention are shown in Table 1.

[0081] Table 1. Adsorption and attenuation performance of aluminum-based lithium adsorbents prepared in Examples 1-6 and Comparative Examples 1-3 of the present invention.

[0082] Table 1 shows the decrease in lithium adsorption capacity of each adsorbent sample in the 100th cycle compared to the 1st cycle. In the algae-free brine experimental group, the lithium adsorbent samples of Examples 1-5 decreased by approximately 2.16%-3.91%, while Comparative Examples 1-3 decreased by 7.13%, 5.82%, and 6.36% respectively. In the algae-containing brine experimental group, the lithium adsorbent samples of Examples 1-5 decreased by approximately 3.01%-5.23%, while Comparative Examples 1-3 decreased by 30.63%, 25.11%, and 15.04% respectively. The lithium adsorbent samples of Comparative Examples 1-3 showed a much greater decrease in lithium adsorption capacity in algae-containing brine than in algae-free brine, indicating that algae and other microorganisms in the brine can cause a significant decrease in the performance of lithium adsorbents. After 100 cycles of adsorption-desorption experiments in algae-containing and algae-free brine, the lithium adsorbent samples in Examples 1-6 did not show a significant decrease in lithium adsorption. The decrease in lithium adsorption in the algae-containing brine group was only slightly higher than that in the algae-free brine group, indicating that these lithium adsorbent samples were only slightly affected by algae and other microorganisms in the brine and had significant resistance to biofouling. The experimental data from Comparative Examples 1, 2, and 3 and Examples 1-6 in algae-containing brine show that lithium adsorbents with the introduction of antibacterial agents or graphite analogs alone, such as the lithium adsorbent samples in Comparative Examples 2 and 3, also have certain antifouling performance. The decrease in lithium adsorption was between that of conventional lithium adsorbent samples and lithium adsorbent samples doped with both graphite analogs and antibacterial agents. This demonstrates the synergistic effect of graphite analogs and antibacterial agents, which improves the antifouling performance of lithium adsorbents.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing an aluminum-based lithium adsorbent, characterized in that, Includes the following steps: S1: Mix water-soluble lithium salt, water-soluble aluminum salt and antibacterial agent to prepare a mixed solution; then stir and heat, adjust the pH of the mixed solution to neutral, continue stirring the reaction, and filter, dry, pulverize and sieve the product to obtain lithium adsorbent active powder. S2: Dissolve the binder in a solvent, add the lithium adsorbent active powder, mix evenly, granulate, dry and sieve to obtain the aluminum-based lithium adsorbent. In the process of preparing the mixture in S1, or in the granulation process described in S2, a graphite analogue is added.

2. The method for preparing an aluminum-based lithium adsorbent according to claim 1, characterized in that, The graphite analogue is at least one of graphene, graphene oxide, carbon nanotubes, Ketjen black, acetylene black, carbon fiber, activated carbon, and furnace black; the antibacterial agent includes at least one of elemental copper, elemental gallium, elemental silver, copper-containing compounds, gallium-containing compounds, and silver-containing compounds.

3. The method for preparing an aluminum-based lithium adsorbent according to claim 2, characterized in that, The copper-containing compound is selected from at least one of copper chloride and copper sulfate; the gallium-containing compound is gallium nitrate nonahydrate; and the silver-containing compound is silver nitrate.

4. The method for preparing an aluminum-based lithium adsorbent according to claim 1, characterized in that, In the mixture, the concentration of aluminum ions is 1.2~1.5 mol / L, and the molar ratio of aluminum ions in the water-soluble aluminum salt to lithium ions in the water-soluble lithium salt is 1:(1~3).

5. The method for preparing an aluminum-based lithium adsorbent according to claim 1, characterized in that, The particle size of the graphite analog is 1 nm to 1000 nm; the mass ratio of the graphite analog to the amount of aluminum ions in the water-soluble aluminum salt is (1.2~4) g: 1 mol.

6. The method for preparing an aluminum-based lithium adsorbent according to claim 1, characterized in that, The molar ratio of the antibacterial agent to aluminum ions is (1~50):1000.

7. The method for preparing an aluminum-based lithium adsorbent according to claim 1, characterized in that, In step S1, the drying temperature is 60~80℃ and the time is 8~12h; the particle size of the lithium adsorbent active powder is no greater than 200 mesh.

8. The method for preparing an aluminum-based lithium adsorbent according to claim 1, characterized in that, The mass ratio of the binder to the lithium adsorbent active powder is (0.05~0.2):

1.

9. An aluminum-based lithium adsorbent, characterized in that, It is prepared by the method described in any one of claims 1 to 8.

10. The application of the aluminum-based lithium adsorbent as described in claim 9 in lithium extraction from salt lakes.

Images