A photosensitive lithium ion selective adsorption material and preparation method thereof

Abstract

This invention relates to a lithium-ion selective adsorbent material and its preparation method. The preparation method includes the following steps: S1, dissolving graphene oxide and cyclohexane in deionized water and sonicating to obtain a mixed dispersion; S2, adding an organic solution containing an acyl chloride organic ligand to the dispersion obtained in step S1, continuing sonication, and allowing it to stand after sonication to obtain a reaction material; S3, filtering, washing, and vacuum drying the above reaction material to obtain a photosensitive lithium-ion selective adsorbent material. The photosensitive lithium-ion selective adsorbent material prepared by the above method has a regular morphology, complete structure, fast adsorption rate, high adsorption capacity (5-13 mmol / g), and high lithium selectivity (1-15). Compared with traditional adsorbent materials, this material has a short preparation cycle, low energy consumption, and no high temperature or high pressure hazards, making it economical, energy-saving, and environmentally friendly, with good application prospects.

Description

Technical Field

[0001] This invention relates to the field of lithium adsorption technology, specifically to photosensitive lithium-ion selective adsorption materials and their preparation methods. Background Technology

[0002] Lithium (Li) is the lightest metallic element in the periodic table. It is also a strategically important non-renewable element in advanced technological applications such as lithium-ion batteries, glass, ceramics, pharmaceuticals, gas absorbers, and aluminum alloy manufacturing. With the continuous development of the new energy industry, lithium-ion batteries, with their advantages of high energy density, light weight, and environmental friendliness, have been widely used in numerous digital products such as mobile phones, laptops, electronic devices, and new energy vehicles. Furthermore, due to the widespread application of new energy industries, lithium resources have become an indispensable energy raw material, exacerbating the lithium resource shortage problem. In the past decade, lithium consumption has surged from 24.5 kt to 56.0 kt, and is expected to continue to rise in the future. It is reported that most lithium resources are naturally stored in brine and seawater. Therefore, there is an urgent need to design and develop cost-effective new technologies to economically extract lithium resources from brine and seawater to cope with the crisis of explosive demand growth and solve the lithium resource shortage problem.

[0003] Currently, lithium extraction technologies mainly include precipitation, extraction, membrane separation, and adsorption. Among these technologies, precipitation is relatively mature, but it suffers from low lithium recovery rates, high energy consumption, and is unsuitable for solutions with low lithium-ion concentrations. Extraction offers high lithium selectivity, but the organic solvents involved can easily cause secondary pollution. Membrane separation technology is convenient to operate, compact in structure, has low maintenance costs, and provides good selective separation of lithium and magnesium; however, membrane surface fouling, which reduces membrane separation performance, is a significant issue. In comparison, adsorption technology offers advantages such as simple process, low pollution levels, low energy consumption, and low lithium extraction costs, making it one of the most commonly used methods for lithium extraction from salt lakes.

[0004] Currently, the most common lithium-ion adsorbents are mainly inorganic and organic materials. Inorganic adsorbents primarily include manganese-based, titanium-based, aluminum-based, and iron-based lithium-ion sieves, such as LiMn2O4, Li2TiO3, Li / Al-LDHs, and Li... 1.33 Fe x Mn 1.67-x O4. Although these adsorbents have high lithium-ion adsorption capacity, their regeneration process suffers from significant dissolution loss and long adsorption equilibrium time. Organic adsorbents are mainly porous nanomaterials such as covalent organic frameworks (COFs), metal-organic frameworks (MOFs), and covalent organic networks (CONs). These materials have easily tunable pore structures, large specific surface areas, and strong chemical and thermal stability, and are considered potential lithium-ion adsorbents.

[0005] Photoresponsive lithium adsorption is a popular technology that has emerged in recent years. It mainly utilizes the structural transformations or photoisomerization of materials under different light conditions to achieve the adsorption and desorption of lithium ions. Light is the most abundant clean energy source in nature. Using light to achieve lithium ion adsorption and desorption not only overcomes the problems of slow adsorption time, low desorption efficiency, and large solubility loss associated with traditional methods, but also avoids the secondary environmental pollution caused by the use of large amounts of acids, alkalis, or organic reagents in the regeneration process of porous materials.

[0006] Chinese invention patent application CN115888667A discloses a photosensitive regenerated lithium adsorbent and its preparation method. The preparation method includes the following steps: 1) dissolving a metal-organic framework, spiropyran, and an initiator in a solvent and stirring until a mixed solution is obtained; 2) removing the solvent from the mixed solution in step 1) and then heating the solution to obtain a reaction material; 3) filtering, washing, and drying the reaction material to obtain the photosensitive regenerated lithium ion adsorbent. This method utilizes the conversion of ion sites of spiropyran under visible / ultraviolet light to achieve adsorption / desorption. However, spiropyran is expensive, resulting in high production costs for the above method. Summary of the Invention

[0007] In view of the above-mentioned prior art, the present invention provides a photosensitive lithium-ion selective adsorption material and its preparation method. The inventors have discovered that, like spiropyran, organic ligands with azobenzene unit structures also have photostimulation response characteristics. Therefore, azobenzene can be used to achieve photoresponsive isomerization under visible / ultraviolet light, inducing a change in the diameter of the ring cavity of the ring-ring, thereby achieving efficient selective adsorption of ions.

[0008] Guided by the above-mentioned approach, this invention constructs a covalent organic network adsorbent material using cyclopentadiene and acyl chloride-containing organic ligands (such as azobenzene-4,4'-dicarbonyl chloride) as raw materials. Similar to crown ethers, cyclopentadiene is a flexible tetranitrogen heterocycle. Here, cyclopentadiene is a flexible and deformable tetranitrogen heterocycle, while azobenzene is a highly efficient and reliable photo-switching unit. From a stereochemical perspective, under ultraviolet or visible light irradiation, cyclopentadiene undergoes corresponding stereoisomerization changes with the isomerization of azobenzene. This covalent organic network adsorbent material comprises azobenzene units with photo-switching function and a structurally deformable tetranitrogen heterocycle. Furthermore, it is known that a series of crown ethers can form stable complexes with alkali metal ions and alkaline earth metal ions. The stability of the complex is optimal when the diameter of a specific metal ion matches the diameter of the crown ether ring cavity. Although nitrogen has a weaker adsorption capacity for alkali / alkaline earth metal ions than oxygen in crown ethers, it still exhibits excellent selective binding ability for alkali / alkaline earth metal ions. Graphene oxide (GO) has a mature preparation method. Commercial GO solutions are thin (~2nm), GO sheets are large, have good dispersibility, and can be functionalized, making them one of the ideal choices as a carrier for constructing adsorbent materials.

[0009] Therefore, the photosensitive lithium-ion selective adsorption material provided by the present invention has excellent adsorption performance for lithium ions under visible light and can achieve desorption of lithium ions under ultraviolet light irradiation, thereby achieving the function of photo-controlled adsorption and desorption of lithium ions.

[0010] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0011] A photosensitive lithium-ion selective adsorbent material, wherein the photosensitive lithium-ion selective adsorbent material is a polymer formed by loading cyclohexane and acyl chloride-containing organic ligands on graphene oxide as a carrier, wherein the molar ratio of cyclohexane and acyl chloride-containing organic ligands is 1:(0.5-5).

[0012] Furthermore, the molar ratio of cyclohexane to the acyl chloride-containing organic ligand is 2:1.

[0013] Furthermore, the ratio of graphene oxide to cyclohexane is 2-5 mg: 0.4 mmol / L, preferably 3 mg: 0.4 mmol / L.

[0014] Furthermore, the acyl chloride-containing organic ligand is at least one of pyromellitic tricarboxylic acid chloride, terephthaloyl chloride, octanoyl chloride, adipicoyl chloride, or azobenzene-4,4'-dicarbonyl chloride, preferably azobenzene-4,4'-dicarbonyl chloride.

[0015] Furthermore, the photosensitive lithium-ion selective adsorption material has at least one of the following (1) to (3):

[0016] The adsorption capacity for lithium ions under visible light is 5-13 mmol / g, preferably 10-13 mmol / g;

[0017] The selective adsorption molar ratio of lithium and magnesium under visible light is 1-15, preferably 3-10;

[0018] After the photosensitive lithium-ion selective adsorbent material is used up, it is irradiated under ultraviolet light to obtain a regenerated photosensitive lithium-ion selective adsorbent material. Preferably, the regenerated photosensitive lithium-ion selective adsorbent material is irradiated under ultraviolet light for 10-30 minutes, and the adsorption performance of the obtained material is restored to 90% or more of the original adsorption performance.

[0019] This invention also protects a method for preparing the photosensitive lithium-ion selective adsorption material, comprising the following steps:

[0020] Step S1: Dissolve graphene oxide and cyclohexane in deionized water, stir and then sonicate to obtain a mixed dispersion;

[0021] Step S2: Add an organic solution containing an acyl chloride organic ligand to the mixed dispersion obtained in step S1, continue sonication, and then let it stand to obtain the reaction mixture;

[0022] In step S3, the reactants are allowed to react statically, then filtered, washed, and vacuum dried to obtain a photosensitive lithium-ion selective adsorption material.

[0023] Furthermore, the method has one or more of the following technical features:

[0024] In step S1, the graphene oxide is at least one of graphene oxide dispersion, graphene oxide powder, and graphene oxide sol.

[0025] In step S2, the organic solution containing the acyl chloride organic ligand is obtained by dispersing the acyl chloride organic ligand in an organic solvent, wherein the organic solvent is a non-polar solvent, preferably at least one of petroleum ether, n-hexane, n-pentane, n-heptane, carbon tetrachloride, isooctane, toluene, or dichloromethane.

[0026] The ultrasound described in steps S1 and S2 is at least one of an ultrasonic vibrating rod or an ultrasonic generator, with a power of 40-100KHz and an ultrasound duration of 30-60min.

[0027] Steps S1 and S2 are both performed at room temperature;

[0028] In step S3, the reaction temperature is room temperature and the reaction time is 12-48 hours.

[0029] This invention also protects the application of the photosensitive lithium-ion selective adsorption material in lithium-ion adsorption.

[0030] The present invention also protects a lithium-ion selective adsorbent comprising the aforementioned photosensitive lithium-ion selective adsorbent material.

[0031] The present invention also protects a method for regenerating the lithium-ion selective adsorbent, comprising irradiating the lithium-ion selective adsorbent under ultraviolet light for 10-30 minutes to obtain a regenerated lithium-ion selective adsorbent.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] This invention relates to a method for preparing a photosensitive lithium-ion selective adsorbent material. The method involves a covalent organic network adsorbent material formed by cyclohexane and an acyl chloride-containing organic ligand, which is loaded onto graphene oxide via hydrogen bonds. This alters the symmetry structure of graphene oxide, improving ion separation and resulting in a more stable material structure. The preparation process provided by this invention is simple, uses inexpensive raw materials, and is universally applicable. The prepared photosensitive lithium-ion selective adsorbent material exhibits advantages such as high lithium-ion adsorption capacity and high lithium-ion selectivity. Furthermore, the photosensitive lithium-ion selective adsorbent material can achieve lithium-ion adsorption under visible light and desorption under ultraviolet light, with its adsorption performance reaching over 90% of the original adsorption performance after ultraviolet irradiation. Attached Figure Description

[0034] Figure 1 This is a SEM image of the photosensitive lithium-ion selective adsorption material obtained in Example 1;

[0035] Figure 2 This is a TEM image of the photosensitive lithium-ion selective adsorption material obtained in Example 1;

[0036] Figure 3 This is a SEM image of the graphene oxide powder used in Example 6. Detailed Implementation

[0037] To more clearly illustrate the technical solutions of the embodiments of the present invention, although preferred embodiments of the present invention are described below, it should be understood that the following figures only show some embodiments of the present invention, and the present invention can be implemented in various forms and should not be limited to the embodiments described herein. Where specific conditions are not explicitly specified in the embodiments, they should be performed in accordance with the conditions described in the literature in the art or according to the product manual. It should be clearly stated that all embodiments listed herein are merely illustrative and do not imply limitation on the scope of the present invention.

[0038] Example 1

[0039] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0040] (1) Take 0.3 mL of 10 mg / mL graphene oxide dispersion and 0.4 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0041] (2) Add 0.2 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0042] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain the photoresponsive lithium ion adsorption material.

[0043] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0044] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0045] The lithium-ion adsorbent material prepared in this example has a lithium-ion adsorption capacity of 12.82 mmol / g, a lithium-magnesium selectivity of 9.17, and a lithium-ion adsorption capacity of 11.79 mmol / g after regeneration. The lithium-magnesium selectivity was obtained by comparing the adsorption capacities of lithium and magnesium measured by ICP-MS.

[0046] Figure 1 The image shows the SEM characterization results of the lithium-ion adsorbent material prepared in this embodiment. Figure 2 The images shown are TEM characterization results of the lithium-ion adsorbent material prepared in this embodiment. Figure 1 and Figure 2 It can be seen that the surface of graphene oxide was successfully loaded with the polymers of cyclohexane and azobenzene-4,4'-dicarbonyl chloride.

[0047] Example 2

[0048] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0049] (1) Take 0.1 mL of 10 mg / mL graphene oxide dispersion and 0.4 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0050] (2) Add 0.2 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0051] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0052] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0053] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0054] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 1.66 mmol / g, a lithium-magnesium selectivity of 0.12, and a lithium-ion adsorption capacity of 1.46 mmol / g after regeneration.

[0055] Example 3

[0056] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0057] (1) Take 0.2 mL of 10 mg / mL graphene oxide dispersion and 0.4 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0058] (2) Add 0.2 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0059] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0060] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0061] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0062] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 3.89 mmol / g, a lithium-magnesium selectivity of 1.42, and a lithium-ion adsorption capacity of 3.54 mmol / g after regeneration.

[0063] Example 4

[0064] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0065] (1) Take 0.4 mL of 10 mg / mL graphene oxide dispersion and 0.4 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0066] (2) Add 0.2 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0067] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0068] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0069] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0070] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 7.93 mmol / g, a lithium-magnesium selectivity of 7.33, and a lithium-ion adsorption capacity of 7.31 mmol / g after regeneration.

[0071] Example 5

[0072] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0073] (1) Take 0.5 mL of 10 mg / mL graphene oxide dispersion and 0.4 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0074] (2) Add 0.2 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0075] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0076] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0077] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0078] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 5.69 mmol / g, a lithium-magnesium selectivity of 3.48, and a lithium-ion adsorption capacity of 5.06 mmol / g after regeneration.

[0079] The above embodiments used the same raw materials, but different masses of graphene oxide. Experiments compared the lithium adsorption effects of traditional lithium-ion adsorbent materials and the lithium-ion adsorbent materials prepared in the embodiments. The traditional lithium-ion adsorbent materials were organic materials, such as manganese-based, titanium-based, aluminum-based, and iron-based oxides and crown ether-based adsorbents. In this experiment, a manganese-based lithium-ion adsorbent was used as a control. The control sample was purchased from Nanjing Gongcheng Energy-Saving New Materials Research Institute Co., Ltd. x Mn y O z The reagent type was specified. The experimental results are as follows:

[0080] Table 1 Comparison of the adsorption effects of lithium-ion adsorption materials and traditional adsorption materials

[0081]

[0082]

[0083] As can be seen from Examples 1-5, the lithium-ion adsorbent material prepared by this invention exhibits excellent performance in both adsorption capacity and adsorption rate. Furthermore, the addition of graphene oxide significantly improves the lithium adsorption capacity. With increasing graphene oxide mass, the lithium-ion adsorption capacity initially increases and then decreases, indicating that excessive graphene oxide can lead to the masking of adsorption sites, which is detrimental to lithium-ion adsorption.

[0084] Furthermore, the lithium-ion adsorbent material prepared by this invention also exhibits excellent regeneration performance under ultraviolet light, generally achieving a regeneration efficiency of over 90%. In comparison, the lithium-ion adsorbent material prepared by this invention can rapidly extract lithium ions from water and can be regenerated under ultraviolet light, effectively avoiding the secondary environmental pollution problems caused by regeneration using acid or alkali reagents.

[0085] Example 6

[0086] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0087] (1) Take 3 mg of graphene oxide powder (e.g. Figure 3(as shown) and 0.4 mmol of cyclohexane were dissolved in 2 mL of deionized water, stirred for 30 min and then sonicated for 30 min to obtain a mixed dispersion;

[0088] (2) Add 0.2 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0089] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0090] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0091] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0092] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 11.21 mmol / g, a lithium-magnesium selectivity of 8.41, and a lithium-ion adsorption capacity of 10.11 mmol / g after regeneration.

[0093] Example 7

[0094] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0095] (1) Take 0.3 mL of 10 mg / mL graphene oxide dispersion and 0.2 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0096] (2) Add 0.2 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0097] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0098] (4) Take 0.2g of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626mg / L. Stir for 3h and control the temperature at 25℃. Use ICP-MS to determine the adsorption capacity of the material.

[0099] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0100] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 8.75 mmol / g, a lithium-magnesium selectivity of 6.12, and a lithium-ion adsorption capacity of 8.05 mmol / g after regeneration.

[0101] Example 8

[0102] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0103] (1) Take 0.3 mL of 10 mg / mL graphene oxide dispersion and 0.2 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0104] (2) Add 0.4 mmol of azobenzene-4,4'-dicarbonyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0105] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0106] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0107] (5) The adsorbed lithium ion adsorbent material was irradiated under ultraviolet light for 10 min and then re-adsorbed. The adsorption capacity of the material was determined by ICP-MS.

[0108] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 8.42 mmol / g, a lithium-magnesium selectivity of 5.88, and a lithium-ion adsorption capacity of 7.74 mmol / g after regeneration.

[0109] Table 2 Comparison of Implementation Effects of Examples 6-8

[0110]

[0111]

[0112] As can be seen from Examples 6-8, changing the molar ratio between cyclohexane and azobenzene-4,4'-dicarbonyl chloride has little effect on the adsorption rate, and both can achieve relatively ideal adsorption capacity and lithium-magnesium selectivity.

[0113] Example 9

[0114] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0115] (1) Take 0.3 mL of 10 mg / mL graphene oxide dispersion and 0.2 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0116] (2) Add 0.4 mmol of pyromellitic acid chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0117] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0118] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0119] (5) The adsorbed lithium ion adsorbent material is regenerated with 1 mol / L HCl or 1 mol / L NaOH and adsorbed again. The adsorption capacity of the material is determined by ICP-MS.

[0120] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 6.17 mmol / g, a lithium-magnesium selectivity of 5.76, and a lithium-ion adsorption capacity of 5.87 mmol / g after regeneration.

[0121] Another portion of the adsorbed lithium-ion adsorbent material was irradiated under ultraviolet light for 10 minutes and then re-adsorbed. The adsorption capacity of the material was measured using ICP-MS. It was found that the material could not adsorb lithium ions, indicating that the material does not have regeneration performance under ultraviolet light when using trimesoyl chloride as the organic ligand.

[0122] Example 10

[0123] A method for preparing a photosensitive lithium-ion selective adsorption material includes the following steps:

[0124] (1) Take 0.3 mL of 10 mg / mL graphene oxide dispersion and 0.2 mmol of cyclohexanetin and dissolve them in 2 mL of deionized water. Stir for 30 min and then sonicate for 30 min to obtain a mixed dispersion.

[0125] (2) Add 0.4 mmol of terephthaloyl chloride and 2 mL of n-hexane to the mixed dispersion, sonicate for 30 min, and let stand for 24 h to obtain the reaction mixture;

[0126] (3) The obtained reaction material was allowed to stand for 24 hours, then filtered, washed and vacuum dried to obtain lithium ion adsorption material.

[0127] (4) Take 20 mg of lithium ion adsorption material and place it in lithium-containing wastewater with a concentration of 1626 mg / L. Stir for 3 h and control the temperature at 25 °C. Use ICP-MS to determine the adsorption capacity of the material.

[0128] (5) The adsorbed lithium ion adsorbent material is regenerated with 1 mol / L HCl or 1 mol / L NaOH and adsorbed again. The adsorption capacity of the material is determined by ICP-MS.

[0129] The lithium-ion adsorption material prepared in this example has a lithium-ion adsorption capacity of 5.88 mmol / g, a lithium-magnesium selectivity of 5.06, and a lithium-ion adsorption capacity of 5.62 mmol / g after regeneration.

[0130] Another portion of the adsorbed lithium-ion adsorbent material was irradiated under ultraviolet light for 10 minutes and then re-adsorbed. The adsorption capacity of the material was measured using ICP-MS. It was found that the material could not adsorb lithium ions, indicating that the material does not have regeneration performance under ultraviolet light when terephthaloyl chloride is used as the organic ligand.

[0131] Table 3 Comparison of Implementation Effects of Examples 9-10

[0132]

[0133]

[0134] As can be seen from Examples 9 and 10, the covalent organic network adsorbent materials composed of cyclopentadiene and acyl chloride-containing organic ligands can achieve relatively ideal adsorption capacity and high lithium-magnesium selectivity. However, when pyromellitic methyl chloride and terephthaloyl chloride are organic ligands, they do not have the ability to be regenerated under ultraviolet light. Therefore, the material regeneration requires a large amount of acid, alkali or organic reagents, which poses a potential risk of secondary environmental pollution.

[0135] The above description only illustrates several specific embodiments of the present invention, but it should not be construed as the scope of protection of the present invention. Any equivalent changes, alterations or modifications of organic ligands, or proportional enlargements or reductions made in accordance with the design spirit of the present invention should be considered to fall within the scope of protection of the present invention.

Claims

1. A photosensitive lithium-ion selective adsorption material, characterized in that: The photosensitive lithium-ion selective adsorption material is a polymer formed by loading cyclohexane and an acyl chloride-containing organic ligand as a carrier using graphene oxide as a support. The acyl chloride-containing organic ligand is at least one of pyromellitic tricarboxylic acid chloride, terephthaloyl chloride, octanoyl chloride, adipoyl chloride, or azobenzene-4,4'-dicarbonyl chloride, wherein the molar ratio of cyclohexane to the acyl chloride-containing organic ligand is 1:(0.5-5).

2. The photosensitive lithium-ion selective adsorption material according to claim 1, characterized in that: The molar ratio of cyclopentaenoic acid to acyl chloride-containing organic ligands is 2:

1.

3. The photosensitive lithium-ion selective adsorption material according to claim 1 or 2, characterized in that: Graphene oxide: Ring-shaped ginseng = 2-5 mg: 0.4 mmol / L.

4. The photosensitive lithium-ion selective adsorption material according to claim 3, characterized in that: Graphene oxide: Ring-ring tenin = 3 mg: 0.4 mmol / L.

5. The photosensitive lithium-ion selective adsorption material according to claim 1 or 2, characterized in that: The acyl chloride-containing organic ligand is azobenzene-4,4'-dicarbonyl chloride.

6. The photosensitive lithium-ion selective adsorption material according to claim 1 or 2, characterized in that: The photosensitive lithium-ion selective adsorption material has at least one of the following (1) to (3): (1) The adsorption capacity for lithium ions under visible light is 5-13 mmol / g; (2) The selective adsorption molar ratio of lithium and magnesium under visible light is 1-15; (3) After the photosensitive lithium ion selective adsorption material is used up, it is irradiated under ultraviolet light to obtain a regenerated photosensitive lithium ion selective adsorption material.

7. The photosensitive lithium-ion selective adsorption material according to claim 6, characterized in that: The photosensitive lithium-ion selective adsorption material has an adsorption capacity of 10-13 mmol / g for lithium ions under visible light.

8. The photosensitive lithium-ion selective adsorption material according to claim 6, characterized in that: The photosensitive lithium-ion selective adsorption material exhibits a selective adsorption molar ratio of 3-10 for lithium and magnesium under visible light.

9. The photosensitive lithium-ion selective adsorption material according to claim 6, characterized in that: When the photosensitive lithium-ion selective adsorbent material is irradiated under ultraviolet light for 10-30 minutes, the regenerated photosensitive lithium-ion selective adsorbent material obtained has an adsorption performance restored to 90% or more of the original adsorption performance.

10. A method for preparing the photosensitive lithium-ion selective adsorption material according to any one of claims 1 to 9, characterized in that: Includes the following steps: Step S1: Dissolve graphene oxide and cyclohexane in deionized water, stir and then sonicate to obtain a mixed dispersion; Step S2: Add an organic solution containing an acyl chloride organic ligand to the mixed dispersion obtained in step S1, continue sonication, and then let it stand to obtain the reaction mixture; In step S3, the reactants are allowed to react statically, then filtered, washed, and vacuum dried to obtain a photosensitive lithium-ion selective adsorption material.

11. The method for preparing photosensitive lithium-ion selective adsorption materials according to claim 10, characterized in that: The method has one or more of the following technical features: i In step S1, the graphene oxide is at least one of graphene oxide dispersion, graphene oxide powder, and graphene oxide sol. ii. In step S2, the organic solution containing the acyl chloride organic ligand is obtained by dispersing the acyl chloride organic ligand in an organic solvent, wherein the organic solvent is a nonpolar solvent; iii. The ultrasound described in steps S1 and S2 is performed using an ultrasound generator with a power of 40-100KHz and an ultrasound duration of 30-60min. iv. Steps S1 and S2 are both performed at room temperature; v. In step S3, the reaction temperature is room temperature and the reaction time is 12-48 hours.

12. The method for preparing photosensitive lithium-ion selective adsorption materials according to claim 11, characterized in that: The organic solvent is at least one of petroleum ether, n-hexane, n-pentane, n-heptane, carbon tetrachloride, isooctane, toluene, or dichloromethane.

13. The use of the photosensitive lithium-ion selective adsorption material according to any one of claims 1 to 9 in lithium-ion adsorption.

14. A lithium-ion selective adsorbent comprising the photosensitive lithium-ion selective adsorbent material according to any one of claims 1 to 9.

15. The method for regenerating the lithium-ion selective adsorbent according to claim 14, characterized in that: The lithium-ion selective adsorbent was irradiated under ultraviolet light for 10-30 minutes to obtain a regenerated lithium-ion selective adsorbent.

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