Solar photocatalytic self-cleaning aluminum salt lithium ion sieve filler and preparation method thereof

Abstract

The present application relates to a kind of solar photocatalytic self-cleaning aluminum salt lithium ion sieve filler and its preparation method, the active component of the filler is xLiCl·2Al (OH) 3·nH2O·yBiOCl, wherein, x=0.05-1, y=0.01-0.1, n=2, 3, 4;Active component accounts for 25%-75% of the mass fraction of filler;Filler lithium ion adsorption capacity is 3-9mg / g under solar irradiation and 20-30 ℃, lithium ion recovery rate is 85%-95%, after 10 cycles of adsorption and desorption, lithium ion adsorption capacity decreases by 8%-12%;After activation and regeneration, lithium ion adsorption capacity recovers to the level before pollution.The solar photocatalytic self-cleaning aluminum salt lithium ion sieve filler of the present application has photocatalytic self-cleaning function, selective adsorption of lithium and organic pollutant degradation is carried out simultaneously, which prevents the accumulation of organic pollutants, thereby improving its organic pollution resistance.

Description

Technical Field

[0001] This invention relates to the technical field of new energy materials, specifically to a photocatalytic self-cleaning aluminum salt lithium ion sieve packing and its preparation method. Background Technology

[0002] Lithium resources in nature are mainly stored in seawater, salt lake brines, oil and gas field brines, and lithium-containing wastewater from chemical and pharmaceutical processes; lithium mineral resources in the Earth's crust are not abundant. The booming lithium-ion battery materials market has spurred the development of dilute lithium liquid resources. Aluminum salt lithium-ion sieves are the only lithium-ion sieves that have achieved industrial-scale application in salt lake brines; manganese-based, titanium-based, and other types of lithium-ion sieves remain in the experimental stage. Processes for extracting lithium from concentrated seawater obtained through desalination, from oil and gas field brines, from waste liquid from spent lithium-ion battery processing, and from fly ash leachate are all under development. The key technology lies in designing and manufacturing lithium-ion sieves with high adsorption capacity and long lifespan.

[0003] The principle of selective adsorption lithium extraction using aluminum salt lithium-ion sieves involves inserting lithium salt molecules, such as lithium chloride, into the layered molecular structure of Al(OH)3, forming a precipitate of LiCl·2Al(OH)3·nH2O. The LiCl in the precipitate is then desorbed using a large amount of water, forming a hydrated Al(OH)3 lithium-ion sieve. In liquid lithium resources where multiple ions coexist, hydrated Al(OH)3 can selectively adsorb LiCl. + Cations and corresponding Cl - The anions re-form LiCl·2Al(OH)3·nH2O compounds. The adsorption and desorption processes of the aluminum salt lithium ion sieve are reversible, and the reaction process is represented as follows:

[0004] LiCl·2Al(OH)3·nH2O+H2O=xLiCl+(1-x)LiCl·2Al(OH)3·(n+1)H2O.

[0005] Experiments have shown that only microcrystalline hydrated Al(OH)3 has a good lithium-ion adsorption capacity under neutral conditions. As an amphoteric compound, hydrated Al(OH)3 suffers significant dissolution loss under acidic or alkaline conditions. Extensive research and development have been conducted both domestically and internationally to improve the performance of aluminum salt lithium-ion adsorbents. Due to the large surface area of ​​aluminum salt lithium-ion sieves, they are more likely to adsorb organic pollutants in oilfield brine. Industry enterprises have requested the development of solar photocatalytic self-cleaning lithium-ion sieves, with the following basic requirements: (1) Large surface area of ​​the lithium-ion sieve to accelerate the adsorption and desorption rate of lithium ions; (2) Large lithium-ion adsorption capacity and high selectivity of the lithium-ion sieve; (3) High efficiency in solar photocatalytic degradation of organic pollutants; (4) Easy separation and recovery after saturated adsorption of lithium-ion sieves; (5) Capable of solar photocatalytic self-cleaning and activation regeneration; (6) Almost no dissolution loss under neutral adsorption and desorption conditions.

[0006] Chinese patent CN108043358B describes the adsorption capacity of the obtained aluminum salt lithium ion sieve packing as 6-8 mg / g, while in actual tests in salt lake brine, the adsorption capacity of the aluminum salt lithium ion sieve is only 1-3 mg / g.

[0007] Chinese patent CN101928828B discloses a method for extracting lithium from salt lake brine by adsorption, which improves the adsorption capacity and adsorption-desorption rate of lithium ion sieves by increasing the adsorption-desorption temperature.

[0008] Chinese patent CN106076243B discloses a microporous aluminum salt lithium adsorbent and its preparation method, filler, and method for enriching lithium ions. By improving the process, the selectivity of lithium ion adsorption and the cycle life of lithium ion sieves are improved. The problem of the gradual decrease in the adsorption capacity of lithium ion sieves is generally considered to be caused by the complex composition of the actual brine system and the adsorption and exchange of heteroatoms.

[0009] US Patent US20170298475 discloses a composition LiX M1 for recovering lithium from brine. x-y M2 y (OH)3, wherein M1 is at least one of Al, Ga, and In, and M2 is Al, Ga, In, Si, Ge, or Sn, M1 and M2 are not the same, or at least one of Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Y, Zr, or Nb, x = 1-1.5, y = 0.1xx, which expands the ideas for modifying aluminum salt lithium ion sieves.

[0010] Chinese patent CN108543516B discloses a lithium-ion selective adsorbent, its preparation method, and a process for extracting lithium from brine. The lithium-ion sieve is loaded onto a carbon nitride carrier with catalytic degradation effect. The photocatalytic degradation of organic pollutants by carbon nitride is used to mitigate the decline in lithium-ion adsorption capacity and cycle life of the lithium-ion sieve during the cyclic adsorption process.

[0011] In summary, existing aluminum salt lithium ion sieves suffer from low adsorption capacity and short service life. Summary of the Invention

[0012] (a) Technical problems to be solved

[0013] To address the shortcomings of existing technologies, this invention provides a solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing and its preparation method, which has the advantages of stable adsorption capacity, long cycle life, and fast lithium ion adsorption and desorption rate, thus solving the problems of low adsorption capacity and short service life of existing aluminum salt lithium ion sieves.

[0014] (II) Technical Solution

[0015] To achieve the above objectives, the present invention provides the following technical solution:

[0016] On the one hand, the present invention provides a solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing, which combines microcrystalline aluminum hydroxide with bismuth oxychloride and further loads it onto a magnetic activated carbon carrier, and presses it into sheet-like, spherical or cylindrical solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing for simulating lithium extraction by adsorption in oilfield brine.

[0017] The active component of the aluminum salt lithium ion sieve packing is xLiCl·2Al(OH)3·4H2O·yBiOCl.

[0018] Where x = 0.05 - 1, y = 0.01 - 0.1, n = 2, 3, 4,

[0019] The active component of the aluminum salt lithium ion sieve packing accounts for 25%-75% of the mass fraction of the packing.

[0020] The microcrystalline aluminum hydroxide is obtained by neutralizing an aqueous solution of aluminum trichloride with ammonia water or gaseous ammonia.

[0021] The bismuth oxychloride is formed by neutralizing bismuth trichloride with ammonia or gaseous ammonia. It is insoluble in water and can efficiently degrade organic pollutants adsorbed by aluminum salt lithium ion sieves, improving their resistance to organic pollution and preventing and delaying the decline in lithium ion adsorption capacity.

[0022] The bismuth oxychloride combined with aluminum hydroxide increases the specific surface area and doubles the solar photocatalytic capacity. It also has a photocatalytic self-cleaning function and can prevent the accumulation of organic pollutants on the surface of aluminum salt lithium ion sieves.

[0023] Preferably, the magnetic activated carbon is a Fenton-like catalyst, which can be used by adding hydrogen peroxide to oxidize and decompose organic pollutants inside the lithium-ion screen in a Fenton-like oxidation manner, thereby clearing the lithium-ion mass transfer channels and rapidly activating and regenerating the aluminum salt lithium-ion screen that has been deactivated by organic contamination.

[0024] On the other hand, the present invention also provides a method for preparing a solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing, comprising three parts: preparation of a magnetic activated carbon support, preparation of the active component of the aluminum salt lithium ion sieve, and preparation of the aluminum salt lithium ion sieve packing. The specific operation steps are as follows:

[0025] Step 1: Dissolve FeCl2 in deionized water to make it uniformly adsorbed in activated carbon powder. Impregnate with ammonia water containing NH3, and then wash with deionized water. Control the molar ratio of C, Fe and NH3. Then heat and dry at 150-200℃ for 2-4 hours to oxidize and deposit ferrous hydroxide in the activated carbon carrier to form magnetic activated carbon powder.

[0026] Step 2: Mix AlCl3, LiCl and BiCl3 powders evenly, dissolve them in deionized water, and let them be completely adsorbed into the magnetic activated carbon powder. Control the molar ratio of AlCl3, LiCl, BiCl3 and C elements. Place in a sealed container with ammonia gas for 2-5 hours. Control the molar ratio of AlCl3, LiCl, BiCl3 and NH3 to ensure that the compounds loaded on the magnetic activated carbon fully absorb ammonia until the surface pH = 8-10. The active component xLiCl·2Al(OH)3·nH2O·yBiOCl precipitate and NH4Cl and LiCl salts are formed in the magnetic activated carbon.

[0027] Step 3: Press the solid precipitate obtained in Step 1 and Step 2 into sheet, spherical or cylindrical fillers, immerse them in deionized water at 20-30℃ for 8-12 hours to dissolve and remove the impurities of ammonium chloride salts and adsorbed lithium chloride, wash, and air dry at room temperature to obtain solar photocatalytic self-cleaning aluminum salt lithium ion sieve filler.

[0028] Preferably, the method is characterized in that: in step 1, FeCl2, which is easily soluble in water, reacts with excess ammonia to produce Fe(OH)2, which is then oxidized by air to produce Fe(OH)3. After heating and drying, Fe3O4 is formed and deposited in the activated carbon carrier.

[0029] The chemical reaction formula is represented as follows:

[0030] 2FeCl2+4NH3·H2O+O2=Fe(OH)2+Fe(OH)3+4NH4Cl

[0031] 4Fe(OH)₂ + O₂ + 2H₂O = 4Fe(OH)₃

[0032] Fe(OH)2+2Fe(OH)3=Fe3O4+4H2O;

[0033] Preferably, the feature is that: in step 2, AlCl3 is produced by reacting water-soluble AlCl3 with excess ammonia to generate microcrystalline Al(OH)3, which avoids both the problem of incomplete Al(OH)3 precipitation and the loss of Al(OH)3 precipitate due to dissolution.

[0034] The chemical reaction formula is represented as follows:

[0035] AlCl3+3NH3·H2O=Al(OH)3+3NH4Cl

[0036] In step 2, LiCl, which is easily soluble in water, reacts with microcrystalline Al(OH)3 to form an aluminum salt lithium ion sieve precursor.

[0037] The chemical reaction formula is represented as follows:

[0038] LiCl+2Al(OH)3+nH2O=LiCl·2Al(OH)3·nH2O

[0039] In step 2, BiCl3, which is easily soluble in water, is hydrolyzed to form BiOCl, a solar photocatalyst that is almost insoluble in water, thereby preventing the loss of bismuth.

[0040] The chemical reaction formula is represented as follows:

[0041] BiCl3+2NH3·H2O=BiOCl+2NH4Cl+H2O.

[0042] (III) Beneficial Effects

[0043] Compared with the prior art, the present invention provides a solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing and its preparation method, which has the following beneficial effects:

[0044] (1) The photocatalytic self-cleaning aluminum salt lithium ion sieve packing in this invention has a photocatalytic self-cleaning function. It selectively adsorbs and extracts lithium and degrades organic pollutants at the same time, preventing the accumulation of organic pollutants and improving the adsorption capacity stability and cycle life of the lithium ion sieve.

[0045] (2) The microcrystalline aluminum hydroxide in this invention uses magnetic activated carbon as a carrier to provide porous mass transfer channels for the aluminum salt lithium ion screen, which accelerates the adsorption and desorption rate of lithium ions. Organic pollutants in oilfield brine are mainly concentrated on the surface of the aluminum salt lithium ion screen packing and are easily degraded by Fenton oxidation.

[0046] (3) The adsorption capacity of the aluminum salt lithium ion sieve packing in this invention is calculated by measuring the lithium ion concentration in the simulated brine before and after adsorption using atomic absorption spectrometry.

[0047] (4) The raw materials used in this invention, such as crystalline aluminum chloride, bismuth chloride, ferrous chloride, ammonia, hydrogen peroxide and activated carbon, are all commercially available chemical reagents.

[0048] (5) In this invention, the simulated oilfield brine is an aqueous solution of n-octane, sodium dodecylbenzenesulfonate and lithium chloride, with a COD of 100-500 mg / L and a lithium ion concentration of 10-50 mg / L. Attached Figure Description

[0049] Figure 1 This is a flowchart illustrating the preparation method of a photocatalytic self-cleaning aluminum salt lithium ion sieve packing according to the present invention. Detailed Implementation

[0050] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1

[0052] This invention provides a solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing, which combines microcrystalline aluminum hydroxide with bismuth oxychloride and further loads it onto a magnetic activated carbon carrier, and presses it into sheet, spherical or cylindrical solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing for simulating lithium extraction from oilfield brine.

[0053] The active component of the aluminum salt lithium ion sieve packing is xLiCl·2Al(OH)3·4H2O·yBiOCl.

[0054] Where x = 0.05 - 1, y = 0.01 - 0.1, n = 2, 3, 4;

[0055] The active component of the aluminum salt lithium ion sieve packing accounts for 25%-75% of the mass fraction of the packing;

[0056] The simulated oilfield brine is an aqueous solution of n-octane, sodium dodecylbenzenesulfonate, and lithium chloride, with a COD of 100-500 mg / L and a lithium ion concentration of 10-50 mg / L.

[0057] In this invention, the filler carrier is magnetic activated carbon with a specific surface area of ​​300-500 m². 2 / g, with an Fe / C molar ratio of 0.005%-0.02%, and the carrier accounting for 25%-75% of the mass fraction of the filler.

[0058] The lithium ion sieve packing material of the present invention has a lithium ion adsorption capacity of 3-9 mg / g under sunlight irradiation and 20-30℃, a lithium ion recovery rate of 85%-95%, and a lithium ion adsorption capacity decrease of 8%-12% after 10 cycles of adsorption and desorption.

[0059] In this invention, the deactivated aluminum salt lithium ion sieve packing is impregnated in an aqueous H2O2 solution with a mass concentration of 0.1%-2% and regenerated by Fenton-like activation for 1-2 hours, and the lithium ion adsorption capacity can be restored to the level before contamination.

[0060] It should be noted that the deactivated aluminum salt lithium ion sieve packing mentioned in this invention is an aluminum salt lithium ion sieve packing with a content lower than the set range.

[0061] In this invention, microcrystalline aluminum hydroxide is obtained by neutralizing an aqueous solution of aluminum trichloride with ammonia or gaseous ammonia. Since excess ammonia cannot dissolve microcrystalline aluminum hydroxide, the quantitatively formed aluminum salt lithium ion sieve has a relatively large lithium ion adsorption capacity and is firmly bonded to the magnetic activated carbon carrier.

[0062] The bismuth oxychloride in this invention has strong photocatalytic ability. It is formed by neutralizing bismuth trichloride with ammonia or gaseous ammonia. It is insoluble in water and can efficiently degrade organic pollutants adsorbed by aluminum salt lithium ion sieves, improve their resistance to organic pollution, and prevent and delay the decline in lithium ion adsorption capacity.

[0063] The bismuth oxychloride and aluminum hydroxide composite in this invention increase the specific surface area and double the photocatalytic capacity. It has a photocatalytic self-cleaning function, which can prevent the accumulation of organic pollutants on the surface of aluminum salt lithium ion screens. It overcomes the problems of low resistance to organic pollution and gradual decrease in adsorption capacity of existing aluminum salt lithium ion screen products, and can extend the cycle life of aluminum salt lithium ion screens. After 10 cycles of adsorption and desorption, the lithium ion adsorption capacity decreases by only 8%-12%, which has outstanding substantive features and significant technological progress.

[0064] This invention selects magnetic activated carbon as a carrier, which is itself a Fenton-like catalyst. By adding hydrogen peroxide as a hydrogen oxidant, organic pollutants inside the lithium-ion screen can be oxidized and decomposed in a Fenton-like oxidation manner, thus clearing the lithium-ion mass transfer channels and rapidly activating and regenerating the aluminum salt lithium-ion screen that has been deactivated by organic contamination. Even when extracting lithium from oilfield brine with severe organic contamination, the lithium-ion adsorption capacity of the aluminum salt lithium-ion screen packing can be restored to the pre-contamination level, demonstrating its innovativeness.

[0065] This invention relates to a photocatalytic self-cleaning aluminum salt lithium-ion sieve packing material suitable for selective adsorption and extraction of lithium from oilfield brine. It can also be applied to lithium extraction from salt lake brine, concentrated seawater from desalination, gas field brine, waste liquid from lithium-ion battery processing, and fly ash leachate. The photocatalytic self-cleaning aluminum salt lithium-ion sieve packing material possesses photocatalytic self-cleaning capabilities, simultaneously performing selective adsorption and extraction of lithium and degradation of organic pollutants, preventing the accumulation of organic pollutants on the surface of the aluminum salt lithium-ion sieve packing material.

[0066] Example 2

[0067] The present invention also provides a method for preparing a solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing, comprising three parts: preparation of a magnetic activated carbon support, preparation of an aluminum salt lithium ion sieve active component, and preparation of an aluminum salt lithium ion sieve packing. The specific operation steps are as follows:

[0068] Step 1: Dissolve 6.8g FeCl2 in deionized water, allowing it to be uniformly adsorbed onto 100g of activated carbon powder. Impregnate with ammonia water containing 2g NH3, then wash with deionized water. Control the molar ratio of C, Fe, and NH3 to be 1:0.005-0.02:0.01-0.1. Then heat and dry at 150-200℃ for 2-4 hours to oxidize and deposit ferrous hydroxide in the activated carbon carrier to form 103g of magnetic activated carbon powder.

[0069] In this step, the FeCl2, which is easily soluble in water, reacts with excess ammonia to produce Fe(OH)2, which is then oxidized by air to produce Fe(OH)3. After heating and drying, Fe3O4 is deposited in the activated carbon carrier.

[0070] The chemical reaction formula is represented as follows:

[0071] 2FeCl2+4NH3·H2O+O2=Fe(OH)2+Fe(OH)3+4NH4Cl

[0072] 4Fe(OH)₂ + O₂ + 2H₂O = 4Fe(OH)₃

[0073] Fe(OH)2+2Fe(OH)3=Fe3O4+4H2O;

[0074] Step 2: Mix 134g AlCl3, 21.2g LiCl, and 3.2g BiCl3 powder evenly, dissolve them in deionized water, and let them be completely adsorbed onto 100g of magnetic activated carbon powder. Control the molar ratio of AlCl3, LiCl, BiCl3, and C elements to be 1:0.5-0.75:0.01-0.1:5-20. Place the mixture in a sealed container with 60g of ammonia gas for 2-5 hours, controlling the molar ratio of AlCl3, LiCl, BiCl3, and NH3 to be AlCl3:NH3 = 1:3.5-4, so that the compounds loaded on the magnetic activated carbon can fully absorb ammonia until the surface pH = 8-10. The active component xLiCl·2Al(OH)3·nH2O·yBiOCl precipitate and NH4Cl and LiCl salts are formed in the magnetic activated carbon, where x = 0.1-1, y = 0.01-0.1, and n = 2, 3, 4.

[0075] In this step, the AlCl3 is readily soluble in water and reacts with excess ammonia to produce microcrystalline Al(OH)3. This avoids both the problem of incomplete Al(OH)3 precipitation and the loss of Al(OH)3 precipitate due to dissolution.

[0076] The chemical reaction formula is represented as follows:

[0077] AlCl3+3NH3·H2O=Al(OH)3+3NH4Cl

[0078] In this step, the LiCl is formed by reacting water-soluble LiCl with microcrystalline Al(OH)3 to form an aluminum salt lithium ion sieve precursor.

[0079] The chemical reaction formula is represented as follows:

[0080] LiCl+2Al(OH)3+nH2O=LiCl·2Al(OH)3·nH2O

[0081] In this step, the BiCl3, which is easily soluble in water, is hydrolyzed to form a BiOCl solar photocatalyst that is almost insoluble in water, thereby preventing the loss of bismuth.

[0082] The chemical reaction formula is represented as follows:

[0083] BiCl3+2NH3·H2O=BiOCl+2NH4Cl+H2O;

[0084] Step 3: Press the solid precipitate obtained in Step 1 and Step 2 into sheet, spherical or cylindrical packing material, immerse it in deionized water at 20-30℃ for 8-12 hours to dissolve and remove the impurities of ammonium chloride salts and adsorbed lithium chloride, wash, and air dry at room temperature to obtain the solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing material.

[0085] In this invention, bismuth oxychloride is used as a solar photocatalyst. After being combined with aluminum hydroxide, the specific surface area increases, the solar photocatalytic ability is enhanced, and the aluminum salt lithium ion sieve is endowed with a solar photocatalytic self-cleaning function.

[0086] The aluminum salt lithium ion sieve of the present invention has the following practical applications:

[0087] Using 20g of aluminum salt lithium ion sieve packing material, and simulating oilfield brine with LiCl aqueous solution containing 200mg / L COD and 20mg / L lithium ion concentration, lithium adsorption was carried out for 6-8 hours under sunlight irradiation and at 20-30℃. The lithium ion adsorption capacity was 4mg / g. After 10 adsorption-desorption cycles, the lithium ion adsorption capacity decreased by 8%-12%. The lithium ion sieve was then immersed in 1% H2O2 aqueous solution for 1 hour, and its lithium ion adsorption capacity was restored to 4mg / g.

[0088] Lithium adsorption was conducted using 20g of aluminum salt lithium-ion sieve packing material and a LiCl aqueous solution with a COD of 200mg / L and a lithium ion concentration of 20mg / L as simulated oilfield brine. In a dark chamber at 20-30℃, the lithium adsorption capacity was 3.6mg / g after 6-8 hours of adsorption-desorption for 10 cycles, decreasing by 40%-50%. Impregnating the deactivated lithium-ion sieve with a 1% H₂O₂ aqueous solution for 2 hours restored its lithium adsorption capacity to 3.6mg / g. The cumulative effect of organic pollutants on the lithium adsorption capacity of the aluminum salt lithium-ion sieve indicates that solar photocatalysis can degrade organic pollutants and maintain stable lithium adsorption capacity.

[0089] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a photocatalytic self-cleaning aluminum salt lithium ion sieve packing, characterized in that: The process comprises three parts: preparation of magnetic activated carbon support, preparation of active components for aluminum salt lithium ion sieves, and preparation of aluminum salt lithium ion sieve packing material. The specific operational steps are as follows: Step 1: Dissolve FeCl2 in deionized water to allow it to be uniformly adsorbed onto activated carbon powder. Impregnate with ammonia water and then wash with deionized water. Control the molar ratio of C, Fe and NH3. Then heat and dry at 150-200℃ for 2-4 hours to allow ferrous hydroxide to oxidize and deposit in the activated carbon carrier to form magnetic activated carbon powder. Step 2: Mix AlCl3, LiCl, and BiCl3 powders evenly and dissolve them in deionized water to ensure they are fully adsorbed onto the magnetic activated carbon powder. Control the molar ratio of AlCl3, LiCl, BiCl3, and C. Place the mixture in a sealed container with ammonia gas for 2-5 hours, controlling the molar ratio of AlCl3, LiCl, BiCl3, and NH3 to ensure the compounds loaded on the magnetic activated carbon fully absorb ammonia until the surface pH is 8-10. The active component xLiCl·2Al(OH)3·nH2O·yBiOCl precipitate and NH4Cl and LiCl salts are formed in the magnetic activated carbon. The active component of the aluminum salt lithium ion sieve filler is xLiCl·2Al(OH)3·4H2O·yBiOCl, where x = 0.05-1, y = 0.01-0.1, and n = 2, 3, 4. Step 3: Press the product obtained in Step 1 and the solid precipitate obtained in Step 2 into sheet, spherical or cylindrical packing materials, immerse them in deionized water at 20-30℃ for 8-12 hours to dissolve and remove impurities of ammonium chloride salts and adsorbed lithium chloride, wash, and air dry at room temperature to obtain a solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing material, which is used to simulate lithium adsorption and extraction from oilfield brine. The active component of the aluminum salt lithium ion sieve packing material accounts for 25%-75% of the mass fraction of the packing material, wherein the aluminum hydroxide is microcrystalline aluminum hydroxide.

2. The preparation method of a photocatalytic self-cleaning aluminum salt lithium ion sieve packing according to claim 1, characterized in that: The magnetic activated carbon is a Fenton-like catalyst. It can be used by adding hydrogen peroxide as an oxidant to oxidize and decompose organic pollutants inside the lithium-ion screen in a Fenton-like oxidation manner, thereby clearing the lithium-ion mass transfer channels and rapidly activating and regenerating the aluminum salt lithium-ion screen that has been deactivated by organic contamination.

3. The preparation method of the solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing according to claim 1, characterized in that: In step 2, AlCl3, which is easily soluble in water, reacts with excess ammonia to produce microcrystalline Al(OH)3. This avoids both the problem of incomplete Al(OH)3 precipitation and the loss of Al(OH)3 precipitate due to dissolution. The chemical reaction formula is represented as follows: AlCl3+3NH3·H2O=Al(OH)3+3NH4Cl In step 2, LiCl, which is easily soluble in water, reacts with microcrystalline Al(OH)3 to form an aluminum salt lithium ion sieve precursor. The chemical reaction formula is represented as follows: LiCl+2Al(OH)3+nH2O=LiCl·2Al(OH)3·nH2O In step 2, BiCl3, which is easily soluble in water, is hydrolyzed to form BiOCl, a solar photocatalyst that is almost insoluble in water, thereby preventing the loss of bismuth. The chemical reaction formula is represented as follows: BiCl3+2NH3·H2O=BiOCl+2NH4Cl+H2O.

4. A solar photocatalytic self-cleaning aluminum salt lithium ion sieve packing material prepared by the method of any one of claims 1-3.

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