Lignin derivative as well as preparation method and application thereof
By preparing lignin derivatives and using the polyhydroxy structure in its skeleton to form multiple amidoxime groups, the problem of low adsorption of uranium in existing adsorption materials is solved, and efficient uranium ion adsorption and low-cost preparation are achieved.
Patent Information
- Application Number
- CN202510296275.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-06-13
AI Technical Summary
The existing adsorbent materials have problems such as low adsorption amount, complex preparation process and high cost.
After reacting lignin, acrylonitrile and calcium methanol, and then reacting with hydroxylamine hydrochloride and dimethylamine solution, lignin derivatives are prepared, and the polyhydroxy structure in the lignin skeleton is fully utilized to form multiple amidoxime groups, thereby increasing the adsorption amount of uranium ions.
The adsorption amount of uranium ion was significantly improved, with the first adsorption amount between 600 and 1000 mg/g. After 5 cycles, the adsorption capacity was maintained, and the preparation process was simple and the cost was low.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparation of adsorption materials, and particularly relates to a lignin derivative, a preparation method thereof and an application thereof. Background Art
[0002] In recent years, with the continuous aggravation of global environmental problems and energy shortage problems, nuclear energy has received unprecedented attention and has become one of the main new energy sources. Nuclear energy releases energy through nuclear reactions, and nuclear fuel is the substance used in nuclear reactions. Among them, uranium, as an indispensable substance in nuclear fuel and due to its strategic resource status, its stable supply is crucial for the sustainable development of China's nuclear industry.
[0003] Currently, the demand for uranium by humans is increasing rapidly, and the content of uranium in the discharged wastewater is also on the rise. Therefore, compared with general heavy metal wastewater, the treatment of uranium-containing wastewater is more urgent.
[0004] The treatment of uranium-containing wastewater generated during the nuclear energy development process and the recovery of uranium in the wastewater have become current research hotspots. The main treatment methods for uranium-containing wastewater are removal and collection, which can not only improve the utilization rate of uranium elements but also reduce the discharge of radioactive uranium waste. Compared with other common uranium-containing wastewater treatment methods, the adsorption method is widely used due to its high adsorption efficiency and relatively low cost. However, the adsorption method has relatively high requirements for adsorbents. Currently, a variety of uranium-adsorbing materials have been developed, such as porous carbon materials, metal-organic framework materials (MOF), covalent organic framework materials (COF), mesoporous silica, metal oxides, etc. The functional groups contained in the adsorption materials are crucial for adsorption.
[0005] Research shows that amidoxime-based materials, due to the C=N double bond in the amidoxime group containing paired electrons and the O atom in the oxime group and the N atom in the amino group having lone pair electrons, are easily chelated with uranyl ions to form stable complexes, thereby achieving the adsorption and enrichment of uranium, showing good adsorption performance and having strong development potential.
[0006] Therefore, it is of great significance to research and obtain a lignin derivative with high uranium adsorption capacity and renewable, as well as a green and environmentally friendly preparation method. Summary of the Invention
[0007] In view of this, the present invention provides a lignin derivative, a preparation method thereof and an application thereof, and the purpose is to solve the technical problems of low uranium adsorption capacity, complex preparation process and high cost of existing adsorption materials.
[0008] In order to achieve the above invention purpose, the present invention provides the following technical solutions:
[0009] The present invention provides a method for preparing a lignin derivative, comprising the following steps:
[0010] 1) reacting lignin, acrylonitrile and calcium methoxide to obtain an intermediate product;
[0011] 2) The intermediate product, hydroxylamine hydrochloride, dimethylamine solution and water are reacted to obtain a lignin derivative.
[0012] Preferably, in step 1), the mass ratio of lignin, acrylonitrile and calcium methoxide is 5-15:81-94:1-4.
[0013] Preferably, in step 1), the reaction temperature is 40-60° C. and the reaction time is 10-16 hours.
[0014] Preferably, in step 2), the dimethylamine solution is an aqueous solution of dimethylamine, and the concentration of the dimethylamine solution is 35-45 wt %.
[0015] Preferably, in the step 2), the mass ratio of the intermediate product, hydroxylamine hydrochloride, dimethylamine solution and water is 5-15:5-10:12-25:50-78.
[0016] Preferably, in step 2), the reaction temperature is 60-100° C. and the reaction time is 12-24 hours.
[0017] The present invention also provides a lignin derivative prepared by the preparation method of the lignin derivative.
[0018] The invention also provides application of the lignin derivative in adsorbing uranium ions in aqueous solution.
[0019] Preferably, the adsorption capacity of the lignin derivative for uranium ions in aqueous solution is 600-1000 mg / g.
[0020] It can be seen from the above technical solutions that, compared with the prior art, the present invention has the following beneficial effects:
[0021] The preparation method of the lignin derivative of the present invention efficiently converts the hydroxyl groups in the lignin into amidoxime groups, fully utilizing the structural characteristics of the multiple hydroxyl groups in the lignin skeleton, so that each lignin molecule contains multiple amidoxime groups; the preparation process is simple, the cost is low, and the cellulose is renewable and easily degradable, and has good application prospects in uranium adsorption and uranium extraction from seawater.
[0022] The lignin derivative prepared by the present invention can well adsorb uranyl ions into its skeleton structure, significantly improving the absorption of UO 2 2+The adsorption capacity and adsorption kinetics of ions have achieved the purpose of increasing the adsorption of uranium ions. The first uranium ion adsorption capacity is between 600 and 1000 mg / g. After being recycled for 5 times, it still has a good adsorption capacity for uranyl ions. DETAILED DESCRIPTION
[0023] The present invention provides a method for preparing a lignin derivative, comprising the following steps:
[0024] 1) reacting lignin, acrylonitrile and calcium methoxide to obtain an intermediate product;
[0025] 2) The intermediate product, hydroxylamine hydrochloride, dimethylamine solution and water are reacted to obtain a lignin derivative.
[0026] In the present invention, the principle of the preparation method is: lignin is first reacted with acrylonitrile under the catalytic action of calcium methoxide to undergo an addition reaction of hydroxyl groups and carbon-carbon double bonds to obtain a lignin intermediate modified with a nitrile group; the intermediate is then reacted with hydroxylamine hydrochloride under the catalytic action of dimethylamine to undergo an addition reaction of hydroxyl groups and amine groups to obtain an amidoxime-modified lignin adsorption material.
[0027] In the present invention, in the step 1), the mass ratio of lignin, acrylonitrile and calcium methoxide is preferably 5-15:81-94:1-4, more preferably 7-13:85-92:2-3, and more preferably 10-12:88-90:2-3.
[0028] In the present invention, the lignin is a macromolecular material having a certain spatial network structure, and the synergistic effect of the amidoxime group and the network skeleton can better complex with the uranyl ions, thereby achieving a good adsorption effect on the uranyl ions and achieving a very high uranyl ion adsorption amount.
[0029] In the present invention, in the step 1), if the proportion of lignin and calcium methoxide is too low, it is not conducive to the occurrence of the reaction and the synthesis efficiency is low; if the proportion is too high, the amount of acrylonitrile is too small, resulting in too high solid content in the reaction, affecting mass transfer and being not conducive to the conversion of lignin hydroxyl groups.
[0030] In the present invention, in the step 1), the reaction temperature is preferably 40-60°C, more preferably 45-55°C, more preferably 50-52°C, and the reaction time is preferably 10-16h, more preferably 11-15h, more preferably 12-14h.
[0031] In the present invention, in the step 1), the reaction temperature is lower than 40°C, which is not conducive to the addition reaction; the reaction temperature is higher than 60°C, acrylonitrile itself is easy to polymerize. The reaction time is less than 10 hours, and the conversion is incomplete; the reaction time exceeds 16 hours, which has little effect on improving the conversion rate.
[0032] In the present invention, in step 1), after the reaction, cooling, filtration, washing and vacuum drying are sequentially carried out; the temperature of the cooling is preferably 20 - 30 °C, more preferably 22 - 28 °C, and even more preferably 24 - 26 °C; the washing is preferably carried out by first washing with absolute ethanol and then with water. The number of times of washing with absolute ethanol is preferably 1 - 3 times, more preferably 2 times, and the number of times of washing with water is preferably 2 - 5 times, more preferably 3 - 4 times; in the vacuum drying, the vacuum degree of the vacuum drying is preferably -0.09 - -0.1 MPa, more preferably -0.092 - -0.098 MPa, and even more preferably -0.095 - -0.096 MPa. The temperature of the vacuum drying is preferably 30 - 50 °C, more preferably 35 - 45 °C, and even more preferably 40 - 42 °C. The time of the vacuum drying is preferably 5 - 7 h, more preferably 5.5 - 6.5 h, and even more preferably 6 h.
[0033] In the present invention, in step 2), the dimethylamine solution is preferably an aqueous solution of dimethylamine, and the concentration of the dimethylamine solution is preferably 35 - 45 wt%, more preferably 37 - 43 wt%, and even more preferably 38 - 40 wt%.
[0034] In the present invention, in step 2), the mass ratio of the intermediate product, hydroxylamine hydrochloride, dimethylamine solution and water is preferably 5 - 15:5 - 10:12 - 25:50 - 78, more preferably 8 - 13:6 - 9:17 - 22:55 - 75, and even more preferably 10 - 12:7 - 8:18 - 20:60 - 65.
[0035] In the present invention, in step 2), when the proportion of the intermediate product is lower than the range defined in the present invention, the amount of the substrate is too small, which is not conducive to the occurrence of the reaction and the synthesis efficiency is low; when the proportion is greater than the range defined in the present invention, mass transfer is affected and it is not conducive to the conversion of the nitrile group in the intermediate product. The amount of hydroxylamine hydrochloride increases with the increase of the amount of the intermediate product, but if it is too low, the conversion of the nitrile group in the intermediate product is incomplete, and if it is too high, it has little effect on the conversion of the nitrile group. Similarly, if the amount of dimethylamine is too low, the catalytic effect is not obvious, and if it is too high, it has little effect on the improvement of the catalytic activity.
[0036] In the present invention, in step 2), the reaction temperature is preferably 60 - 100 °C, more preferably 70 - 90 °C, and even more preferably 80 - 85 °C. The reaction time is preferably 12 - 24 h, more preferably 16 - 22 h, and even more preferably 18 - 20 h.
[0037] In the present invention, in step 2), after the reaction, cooling, filtration, washing and vacuum drying are sequentially carried out; the temperature of the cooling is preferably 20 - 30°C, more preferably 22 - 28°C, and even more preferably 24 - 26°C; the reagent for washing is preferably water, and the number of washing times is preferably 2 - 5 times, more preferably 3 - 4 times; in the vacuum drying, the vacuum degree of the vacuum drying is preferably -0.09 to -0.1 MPa, more preferably -0.092 to -0.098 MPa, and even more preferably -0.095 to -0.096 MPa, the temperature of the vacuum drying is preferably 30 - 50°C, more preferably 35 - 45°C, and even more preferably 40 - 42°C, and the time of the vacuum drying is preferably 5 - 7 h, more preferably 5.5 - 6.5 h, and even more preferably 6 h.
[0038] The present invention also provides a lignin derivative prepared by the preparation method of the lignin derivative described above.
[0039] The present invention also provides the application of the lignin derivative in adsorbing uranium ions in an aqueous solution.
[0040] In the present invention, the adsorption amount of the lignin derivative to uranium ions in the aqueous solution is preferably 600 - 1000 mg / g, more preferably 700 - 950 mg / g, and even more preferably 800 - 900 mg / g.
[0041] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.
[0042] In the embodiments of the present invention, the lignin is purchased from Jinan Shengquan Group Co., Ltd.; calcium methoxide, sodium methoxide, acrylonitrile, hydroxylamine hydrochloride, dimethylamine and methylamine are all purchased from Sinopharm Chemical Reagent Co., Ltd., analytical pure; uranyl nitrate hexahydrate is purchased from Shanghai Merck Chemical Technology Co., Ltd.
[0043] Example 1
[0044] 5 g of lignin, 2 g of calcium methoxide and 93 g of acrylonitrile are added to a 150 mL round-bottom flask, and after reacting at 45°C for 10 h, it is cooled to 25°C. After suction filtration, the solid is first washed 2 times with absolute ethanol and then 3 times with water. The washed product is dried at 40°C under a vacuum degree of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product is measured to be 2% by elemental analysis;
[0045] 5.5 g of the intermediate product, 5 g of hydroxylamine hydrochloride, 12.5 g of dimethylamine solution (concentration: 40 wt%, solvent: water), and 77 g of water were added to a 150 mL round-bottom flask. After reacting at 70 °C for 14 h, it was cooled to 25 °C. After suction filtration, the solid was washed with water 3 times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured to be 4% by elemental analysis.
[0046] Example 2
[0047] 10 g of lignin, 2.5 g of calcium methoxide, and 87.5 g of acrylonitrile were added to a 150 mL round-bottom flask. After reacting at 50 °C for 13 h, it was cooled to 25 °C. After suction filtration, the solid was first washed with absolute ethanol 2 times and then with water 3 times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product was measured to be 3% by elemental analysis.
[0048] 10 g of the intermediate product, 7.5 g of hydroxylamine hydrochloride, 18 g of dimethylamine solution (concentration: 40 wt%, solvent: water), and 64.5 g of water were added to a 150 mL round-bottom flask. After reacting at 80 °C for 18 h, it was cooled to 25 °C. After suction filtration, the solid was washed with water 3 times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured to be 5% by elemental analysis.
[0049] Example 3
[0050] 13 g of lignin, 3.5 g of calcium methoxide, and 83.5 g of acrylonitrile were added to a 150 mL round-bottom flask. After reacting at 60 °C for 15 h, it was cooled to 25 °C. After suction filtration, the solid was first washed with absolute ethanol 2 times and then with water 3 times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product was measured to be 3.8% by elemental analysis.
[0051] 15 g of the intermediate product, 10 g of hydroxylamine hydrochloride, 20 g of dimethylamine solution (concentration: 40 wt%, solvent: water), and 55 g of water were added to a 150 mL round-bottom flask. After reacting at 100 °C for 20 h, it was cooled to 25 °C. After suction filtration, the solid was washed with water 3 times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured to be 6.2% by elemental analysis.
[0052] Comparative Example 1
[0053] 10 g of lignin, 3 g of an aqueous sodium hydroxide solution (concentration: 10 wt%), and 87 g of acrylonitrile were added to a 150 mL round-bottom flask and reacted at 50 °C for 13 h. After cooling to 25 °C, the solid was filtered and washed twice with absolute ethanol and then three times with water. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product was measured by elemental analysis to be 0.2%;
[0054] 10 g of the intermediate product, 7.5 g of hydroxylamine hydrochloride, 18 g of an aqueous sodium hydroxide solution (concentration: 20 wt%), and 64.5 g of water were added to a 150 mL round-bottom flask and reacted at 80 °C for 18 h. After cooling to 25 °C, the solid was filtered and washed three times with water. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured by elemental analysis to be 0.2%.
[0055] Comparative Example 2
[0056] 10 g of lignin, 2.5 g of calcium methoxide, and 87.5 g of acrylonitrile were added to a 150 mL round-bottom flask and reacted at 50 °C for 13 h. After cooling to 25 °C, the solid was filtered and washed twice with absolute ethanol and then three times with water. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product was measured by elemental analysis to be 3%;
[0057] 10 g of the intermediate product, 7.5 g of hydroxylamine hydrochloride, 40 g of an aqueous sodium hydroxide solution (concentration: 20 wt%), and 42.5 g of water were added to a 150 mL round-bottom flask and reacted at 80 °C for 18 h. After cooling to 25 °C, the solid was filtered and washed three times with water. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured by elemental analysis to be 3%.
[0058] Comparative Example 3
[0059] 10 g of lignin, 3 g of an aqueous sodium hydroxide solution (concentration: 10 wt%), and 87 g of acrylonitrile were added to a 150 mL round-bottom flask and reacted at 50 °C for 13 h. After cooling to 25 °C, the solid was filtered and washed twice with absolute ethanol and then three times with water. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product was measured by elemental analysis to be 0.2%;
[0060] 10 g of the intermediate product, 7.5 g of hydroxylamine hydrochloride, 18 g of dimethylamine solution (concentration: 40 wt%, solvent: water), and 64.5 g of water were added to a 150 mL round-bottom flask, and the reaction was carried out at 80 °C for 18 h. After cooling to 25 °C, the solid was filtered and washed with water three times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured by elemental analysis to be 0.4%.
[0061] Comparative Example 4
[0062] 10 g of lignin, 2.5 g of sodium methoxide, and 87.5 g of acrylonitrile were added to a 150 mL round-bottom flask, and the reaction was carried out at 50 °C for 13 h. After cooling to 25 °C, the solid was filtered and first washed with anhydrous ethanol twice and then with water three times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product was measured by elemental analysis to be 0.7%;
[0063] 10 g of the intermediate product, 7.5 g of hydroxylamine hydrochloride, 18 g of dimethylamine solution (concentration: 40 wt%, solvent: water), and 64.5 g of water were added to a 150 mL round-bottom flask, and the reaction was carried out at 80 °C for 18 h. After cooling to 25 °C, the solid was filtered and washed with water three times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured by elemental analysis to be 0.8%.
[0064] Comparative Example 5
[0065] 10 g of lignin, 2.5 g of calcium methoxide, and 87.5 g of acrylonitrile were added to a 150 mL round-bottom flask, and the reaction was carried out at 50 °C for 13 h. After cooling to 25 °C, the solid was filtered and first washed with anhydrous ethanol twice and then with water three times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain an intermediate product. The nitrogen content of the intermediate product was measured by elemental analysis to be 3%;
[0066] 10 g of the intermediate product, 7.5 g of hydroxylamine hydrochloride, 20 g of monomethylamine solution (concentration: 40 wt%, solvent: water), and 62.5 g of water were added to a 150 mL round-bottom flask, and the reaction was carried out at 90 °C for 18 h. After cooling to 25 °C, the solid was filtered and washed with water three times. The washed product was dried at 40 °C under a vacuum of -0.095 MPa for 6 h to obtain a lignin derivative. The nitrogen content of the lignin derivative was measured by elemental analysis to be 3%.
[0067] The lignin derivatives obtained in Examples 1 - 3 and Comparative Examples 1 - 5 were subjected to performance testing:
[0068] Adsorption performance detection: The lignin derivatives obtained in Examples 1 to 3 and Comparative Examples 1 to 5 were used as adsorption materials respectively to carry out the following adsorption performance detection steps, and the detection results are shown in Table 1.
[0069] Adsorption performance detection steps: Weigh 5 mg of the adsorption material and add it to 200 mL of uranyl nitrate aqueous solution (concentration: 50 mg / L, pH value: 8), stir at room temperature for 10 h, and use inductively coupled plasma to measure the concentration of uranium (UO 2 2+ ) in the solution. The adsorption amount of uranium is calculated using Equation I:
[0070] q e = V(C 0 - C e ) / m Equation I
[0071] where q e is the equilibrium adsorption amount, V is the volume of the uranyl nitrate aqueous solution, C 0 is the initial concentration of uranium, C e is the equilibrium adsorption concentration of uranium, and m is the mass of the adsorption material.
[0072] Table 1 Adsorption performance detection results of the lignin derivatives obtained in Examples 1 to 3 and Comparative Examples 1 to 5
[0073] Sample Adsorption capacity / (mg / g) Example 1 618 Example 2 812 Example 3 960 Comparative Example 1 15 Comparative Example 2 17 Comparative Example 3 19 Comparative Example 4 21 Comparative Example 5 20
[0074] As can be seen from Table 1, the adsorption amounts of the lignin derivatives obtained in Examples 1 to 3 for uranium ions are all above 618 mg / g, while the highest adsorption amount of the lignin derivatives obtained in Comparative Examples 1 to 5 for uranium ions is only 21 mg / g, showing a huge difference. It can be seen that the lignin derivatives prepared in the present invention can well adsorb uranyl ions into their framework structures, significantly improving the adsorption capacity and adsorption kinetics for UO 2 2+ ions, and achieving the purpose of increasing the adsorption amount of uranium ions.
[0075] Regeneration performance detection: The lignin derivative obtained in Example 3 was subjected to the following steps:
[0076] Weigh 5 mg of the lignin derivative obtained in Example 3 and add it to 200 mL of uranyl nitrate aqueous solution (concentration: 50 mg / L, pH value: 8), stir at room temperature for 10 h, use inductively coupled plasma to measure the concentration of uranium (UO 2 2+ ) in the solution, and calculate the adsorption amount of uranium (calculated using Equation I). After filtering the liquid after adsorption to obtain a solid, wash the obtained solid four times with water to complete regeneration. Repeat the above steps four times, and the regeneration detection results are shown in Table 2.
[0077] Table 2 Detection results of the regeneration performance of the lignin derivative obtained in Example 3
[0078]
[0079]
[0080] As can be seen from Table 2, after the lignin derivative obtained in Example 3 was repeatedly adsorbed five times, its uranium ion adsorption capacity could still reach 898 mg / g, with a difference of only 62 mg / g from the adsorption capacity of the first adsorption, and the adsorption capacity reduction rate was 6.45%. It can be seen that the lignin derivative obtained by the present invention has excellent regeneration and adsorption performance.
[0081] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A method for preparing a lignin derivative, characterized in that: The steps include: 1) reacting lignin, acrylonitrile and calcium methoxide to obtain an intermediate product; 2) The intermediate product, hydroxylamine hydrochloride, dimethylamine solution and water are reacted to obtain a lignin derivative.
2. The method for preparing a lignin derivative according to claim 1, characterized in that: In the step 1), the mass ratio of lignin, acrylonitrile and calcium methoxide is 5-15:81-94:1-4.
3. The method for preparing a lignin derivative according to claim 2, characterized in that: In the step 1), the reaction temperature is 40-60° C. and the reaction time is 10-16 hours.
4. The method for preparing a lignin derivative according to claim 3, characterized in that: In the step 2), the dimethylamine solution is an aqueous solution of dimethylamine, and the concentration of the dimethylamine solution is 35-45 wt %.
5. The method for preparing a lignin derivative according to claim 1 or 4, characterized in that: In the step 2), the mass ratio of the intermediate product, hydroxylamine hydrochloride, dimethylamine solution and water is 5-15:5-10:12-25:50-78.
6. The method for preparing a lignin derivative according to claim 5, characterized in that: In the step 2), the reaction temperature is 60-100° C. and the reaction time is 12-24 hours.
7. A lignin derivative obtained by the method for preparing a lignin derivative according to any one of claims 1 to 6.
8. Use of the lignin derivative according to claim 7 in adsorbing uranium ions in aqueous solution.
9. The use of the lignin derivative in adsorbing uranium ions in aqueous solution according to claim 8, characterized in that: The adsorption capacity of uranium ions in aqueous solution by lignin derivatives is 600-1000 mg / g.