A carbon-based material, its preparation method and application

Abstract

The present invention relates to the technical field of soil improvement, and discloses a carbon-based material, a preparation method thereof, and an application thereof. The carbon-based material is lignin modified by an electron shuttle. The carbon-based material provided by the present invention performs surface modification on lignin with an electron shuttle. Lignin is rich in resources, easy to obtain as a raw material, low in cost, good in stability and harmless. By combining with an electron shuttle, high electron shuttle active fragments are introduced on the surface, greatly improving the electron shuttle ability, enabling the carbon-based material to have the ability to promote the reduction and dissolution of soil minerals, and can be applied to soil improvement, improve the electron transfer rate between microorganisms and minerals, accelerate mineral dissolution and soil mineral element activation, effectively regulate the soil iron cycle process to enhance soil nutrition, and provide guarantee for the healthy growth of plants; compared with small molecule shuttles, it is not easy to deteriorate or be lost in the environment, can play a role in the soil for a long time, and has great application potential for soil carbon sequestration and quality improvement and ensuring crop nutrition.

Description

Technical Field

[0001] The present invention relates to the technical field of soil improvement, and particularly relates to a carbon-based material, a preparation method thereof, and an application thereof. Background Art

[0002] During the growth period of plants, various micronutrients need to be ingested from the soil. Insufficient intake or imbalance of nutrient elements will lead to large-scale reduction in yield and decline in crop quality. Long-term intake of low-quality crops by humans is likely to cause health problems such as mental retardation, loss of labor ability, and decline in immunity. Moreover, large-scale reduction in crop yield will also cause huge direct economic losses. Therefore, activating soil mineral elements, improving soil quality, and meeting the intake requirements of plant growth are of great significance for ensuring human health and economic development.

[0003] CN 114958384A discloses a method for activating soil using mineral enzymes. After the minerals are pretreated, fermented, dried, and composted, a highly active mineral enzyme treatment agent is obtained. The highly active mineral enzyme treatment agent is used to activate the soil to solve the problem of soil degradation. However, this technology requires more processes, and after the minerals are added to the soil, the metals therein may have a negative effect on the environment. CN 107082716A discloses a value-added urea capable of activating soil and a preparation method thereof. The value-added urea is synthesized from urea, highly active organic matter, chelating agents, and oxidized medium and trace elements, and is used to inhibit the generation of ammonium nitrogen and nitrate nitrogen in the soil and improve fertilizer utilization rate. The urea used in this technology has a relatively high cost and requires the synthesis of value-added urea under high-temperature conditions, and the operating conditions are relatively harsh. In addition, the above technologies cannot activate the mineral nutrients fixed in the minerals and supply them for crop absorption. Summary of the Invention

[0004] The present invention aims to solve at least one of the above technical problems existing in the prior art. For this reason, one of the purposes of the present invention is to provide a carbon-based material; the second purpose of the present invention is to provide a preparation method of this carbon-based material; the third purpose of the present invention is to provide an application of this carbon-based material.

[0005] The basic principle of the present invention is described as follows:

[0006] Lignin widely exists in plants, is rich in resources, and can be obtained through commercial purchase. The active functional groups (hydroxyl groups) contained on its surface have certain reactivity. In the present invention, lignin is surface-modified with an electron shuttle, and by means of chemical synthesis, the two are combined by bonding to introduce an electron shuttle fragment on the surface of lignin, so that lignin has the ability of electron shuttle.

[0007] In order to achieve the above purposes, the technical solutions adopted by the present invention are as follows:

[0008] The first aspect of the present invention provides a carbon-based material, which is lignin modified by an electron shuttle.

[0009] Preferably, the mass ratio of the electron shuttle to lignin is 1:(0.5 - 25); more preferably, the mass ratio of the electron shuttle to lignin is 1:(0.7 - 20).

[0010] Preferably, the electron shuttle is an anthraquinone compound; more preferably, the electron shuttle is anthraquinone-2-carboxylic acid.

[0011] Specifically, anthraquinone-2-carboxylic acid, as a typical electron shuttle, can be commercially purchased, and the raw materials are easily available.

[0012] Preferably, the lignin includes guaiacyl lignin (G-type).

[0013] Specifically, lignin has abundant functional groups, including functional groups on the benzene ring (methoxy and phenolic hydroxyl groups) and functional groups on the side chain structure (alcohol hydroxyl group, carbonyl group, carboxyl group and double bond structure). These functional groups will significantly affect the reaction characteristics of lignin. Methoxy is an important group for distinguishing lignin units and has strong stability. Cleavage from the benzene ring structure requires a strong oxidant. The more methoxy substituents on the benzene ring, the greater the steric hindrance, which will limit the coupling mode between units. The C5 position of the G-type lignin unit has no methoxy functional group, so it can undergo various coupling reactions.

[0014] Preferably, the carbon-based material includes the following raw materials for preparation: lignin, electron shuttle, solvent, catalyst and dehydrating agent.

[0015] Preferably, the mass ratio of the lignin, catalyst and dehydrating agent is 1000:(2 - 60):(40 - 800); more preferably, the mass ratio of the lignin, catalyst and dehydrating agent is 1000:(2.4 - 50):(40 - 750).

[0016] Preferably, the catalyst includes 4-dimethylaminopyridine (DMAP).

[0017] Preferably, the dehydrating agent includes dicyclohexylcarbodiimide (DCC).

[0018] Preferably, the solvent includes C1-C2 chloroalkanes; more preferably, the solvent includes dichloromethane (DCM).

[0019] The second aspect of the present invention provides a preparation method of the carbon-based material described in the first aspect of the present invention, including the following steps:

[0020] S1. Add lignin and an electron shuttle into a reaction device, introduce an inert gas, and add a solvent to obtain a mixed solution;

[0021] S2. Mix a catalyst, a dehydrating agent with the solvent, add them into the mixed solution, and react to obtain the carbon-based material.

[0022] Preferably, in step S1, the solid-liquid ratio of the lignin to the solvent is 1 g:(2 - 30) mL; more preferably, the solid-liquid ratio of the lignin to the solvent is 1 g:(2.5 - 25) mL.

[0023] Preferably, in step S1, the inert gas includes nitrogen.

[0024] Preferably, in step S1, stirring is performed after adding the solvent.

[0025] Preferably, the stirring time is 10 - 20 min; more preferably, the stirring time is 10 - 15 min.

[0026] Preferably, in step S2, the solid-liquid ratio of the catalyst to the solvent is (0.2 - 10) mg:1 mL; more preferably, the solid-liquid ratio of the catalyst to the solvent is (0.24 - 10) mg:1 mL.

[0027] Preferably, in step S2, the reaction time is 24 - 96 h; more preferably, the reaction time is 40 - 80 h.

[0028] Preferably, after the reaction in step S2, the steps of filtration, washing, and drying are further included.

[0029] The third aspect of the present invention provides the application of the carbon-based material described in the first aspect of the present invention in soil improvement.

[0030] Preferably, the soil improvement is to reduce and activate mineral elements in the soil.

[0031] Preferably, the mineral elements include iron, selenium, zinc, and calcium.

[0032] Preferably, the dosage of the carbon-based material is (0.1 - 1.5) g / kg of soil; more preferably, the dosage of the carbon-based material is (0.1 - 1) g / kg of soil.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1) The carbon-based material provided by the present invention uses an electron shuttle to modify the surface of lignin. Lignin is rich in resources, easy to obtain as raw materials, low in cost, good in stability and harmless. By combining with the electron shuttle, high electron shuttle active fragments are introduced on the surface, greatly improving the electron shuttle ability, so that the carbon-based material has the ability to promote the reduction and dissolution of soil minerals;

[0035] 2) The preparation method of the carbon-based material provided by the present invention has simple steps and mild process conditions. It can be carried out at room temperature, with low energy consumption, easy to promote and use, and can realize large-scale industrial production;

[0036] 3) The carbon-based material provided by the present invention has the ability to promote the reduction and dissolution of soil minerals, can be applied to soil improvement, improve the electron transfer rate between microorganisms and minerals, accelerate mineral dissolution and soil mineral element activation, effectively regulate the soil iron cycle process to enhance soil nutrition, and provide guarantee for the healthy growth of plants; compared with small molecule shuttles, this carbon-based material is not easy to deteriorate or lose in the environment and can play a role in the soil for a long time, and has great application potential for soil carbon sequestration and quality improvement and ensuring crop nutrition. Description of the Drawings

[0037] Figure 1 It is the infrared spectrum diagram of carbon-based material 1 in Example 1;

[0038] Figure 2 It is the nuclear magnetic resonance hydrogen spectrum diagram of carbon-based material 1 in Example 1;

[0039] Figure 3 It is the enlarged diagram of the 7.60 - 9.00 ppm interval of the nuclear magnetic resonance hydrogen spectrum of carbon-based material 1 in Example 1;

[0040] Figure 4 It is the scanning electron microscope diagram of carbon-based material 1 in Example 1;

[0041] Figure 5 It is the kinetic curve of the formation of hydrochloric acid-extractable Fe(II) in the reduction stage in Test Example 1;

[0042] Figure 6 It is the kinetic curve of the formation of hydrochloric acid-extractable Fe(II) in the reduction stage in Test Example 2;

[0043] Figure 7 It is the kinetic curve of hydrochloric acid-extractable Fe(II) in the reduction stage in Test Example 3;

[0044] Figure 8 It is the kinetic curve of DOC in the reduction stage in Test Example 3. Detailed Embodiments

[0045] The content of the present invention will be further described in detail through specific embodiments below. Unless otherwise specified, the raw materials, reagents or devices used in the embodiments can be obtained from conventional commercial channels or can be obtained by existing technical methods. Unless otherwise specified, the test or testing methods are all conventional methods in the art.

[0046] In the following examples, the lignin used was purchased from Sichuan Vicibiotech Co., Ltd.

[0047] In the test example, the strain used for mineral reduction was Shewanella MR-1, purchased from the Marine Microbial Culture Collection Center (MCCC), preservation number: LMG 19005. Before use, it was stored in 25% glycerol (v / v) and stored in a -80 °C refrigerator.

[0048] In the test example of rice pot experiment, the soil sample was collected from a paddy field in Jiangmen City, Guangdong Province (soil surface depth 0 - 20 cm). The soil sample was naturally air-dried at room temperature in a dry and cool place in the laboratory. After removing impurities, it was ground through a 2 mm sieve and stored in a plastic container before chemical analysis.

[0049] The synthetic route for preparing the carbon-based material in the embodiment is shown as follows:

[0050]

[0051] Example 1

[0052] In this example, a carbon-based material was prepared as follows:

[0053] S11: Add a magnetic stir bar, 2.0 g of lignin, and 750 mg (3.0 mmol) of anthraquinone-2-carboxylic acid to a 100 mL Schlenk flask. Replace nitrogen three times, then add 30 mL of anhydrous dichloromethane to the Schlenk flask, and place it on a magnetic stirrer at room temperature for 10 min to obtain a mixed solution.

[0054] S21: Dissolve 36 mg of 4-dimethylaminopyridine and 681 mg of dicyclohexylcarbodiimide in 20 mL of dichloromethane, then dropwise add it to the mixed solution obtained in step S11. Stir at room temperature for 48 h. When it is detected by thin-layer chromatography that anthraquinone-2-carboxylic acid is completely converted, filter, wash the filter cake with dichloromethane, and dry to obtain carbon-based material 1.

[0055] Example 2

[0056] In this example, a carbon-based material was prepared as follows:

[0057] S11. Add a magnetic stir bar, 2.0 g of lignin, and 1.25 g (5.0 mmol) of anthraquinone-2-carboxylic acid into a 100 mL Schlenk flask. Replace the nitrogen three times. Then add 30 mL of anhydrous dichloromethane into the Schlenk flask and stir at room temperature for 10 min on a magnetic stirrer to obtain a mixed solution.

[0058] S21. Dissolve 60 mg of 4-dimethylaminopyridine and 1.14 g of dicyclohexylcarbodiimide in 20 mL of dichloromethane, and then dropwise add the resulting solution into the mixed solution obtained in step S11. Stir at room temperature for 72 h. When it is detected by thin-layer chromatography that anthraquinone-2-carboxylic acid is completely converted, filter, wash the filter cake with dichloromethane, and dry it to obtain carbon-based material 2.

[0059] Material Characterization

[0060] 1. Perform infrared spectroscopy test on the carbon-based material 1 prepared in Example 1:

[0061] Figure 1 is the infrared spectrum of carbon-based material 1 in Example 1. It can be seen from Figure 1 that a characteristic peak of the quinone group appears at 1676 cm -1 , indicating that anthraquinone-2-carboxylic acid is successfully coupled with lignin.

[0062] 2. Use deuterated methanol as the solvent and perform nuclear magnetic resonance hydrogen spectrum test on the carbon-based material 1 prepared in Example 1:

[0063] Figure 2 is the nuclear magnetic resonance hydrogen spectrum of carbon-based material 1 in Example 1. Figure 3 is the enlarged view of the 7.60 - 9.00 ppm interval of the nuclear magnetic resonance hydrogen spectrum of carbon-based material 1 in Example 1. It can be seen from Figure 2 and Figure 3 that in the nuclear magnetic resonance hydrogen spectrum of carbon-based material 1, characteristic peaks of anthraquinone aryl hydrogen appear in the 7.60 - 9.00 ppm interval of the hydrogen spectrum chemical shift, indicating that anthraquinone-2-carboxylic acid is successfully coupled with lignin.

[0064] 3. Perform scanning electron microscopy test on the carbon-based material 1 prepared in Example 1:

[0065] Figure 4 is the scanning electron micrograph of carbon-based material 1 in Example 1. It can be seen from Figure 4 that by modifying lignin with anthraquinone-2-carboxylic acid, high electron shuttle active fragments are formed on the surface, which is beneficial to improving the electron shuttle ability of lignin materials.

[0066] Test Example

[0067] Test Preparation and Measurement Method:

[0068] 1. Synthesis and Calibration of Ferrihydrite

[0069] Accurately weigh 8 g of iron(III) nitrate nonahydrate (Fe(NO3)3·9H2O), and add 100 mL of ultrapure water to dissolve it in a beaker. Then prepare 150 mL of 1 mol / L sodium hydroxide solution. Drop the sodium hydroxide solution into the iron(III) nitrate solution within 5 min, and neutralize the pH of the mixture to 7.5. During this process, keep the solution vigorously mixed with an electric stirrer all the time. After the pH stabilizes at 7.5 for 8 h, a suspension of ferrihydrite is obtained. Centrifuge this suspension and wash it with deionized water more than three times to remove the excessive electrolytes in the suspension. Finally, resuspend the washed suspension with 100 mL of deionized water to prepare a ferrihydrite suspension, which can be stored in a refrigerator at 4 °C for three days.

[0070] For the iron minerals in the suspension, it is necessary to calibrate their concentrations to ensure the uniformity of the mineral concentration in the reaction system. Specifically: Ultrasonic the prepared ferrihydrite suspension for 1 h. At the same time, take a 2 mL centrifuge tube and accurately weigh its mass as m1. Transfer 2 mL of the ferrihydrite suspension into this centrifuge tube and freeze-dry it. Its volume is recorded as v. Weigh the mass of the dried centrifuge tube and iron minerals as m2. The concentration c of the ferrihydrite suspension is obtained by the differential calculation method. The calculation formula is as follows:

[0071]

[0072] 2. Microbial activation culture

[0073] (1) Prepare the culture medium required for microbial activation culture. The nutrient components of the culture medium are as follows (1.0 L): 10 g of tryptone, 5 g of yeast extract, and 10 g of sodium chloride. After preparation, adjust the pH of the culture medium to 7.0 using hydrochloric acid and sodium hydroxide. Dispense the culture medium into 250 mL conical flasks, add 100 mL of the culture medium to each flask, and sterilize the culture medium using an autoclave.

[0074] (2) Take out the MR-1 strain from the -80 °C refrigerator and quickly place it on ice to thaw, ensuring that the ice tube thaws on ice to avoid long-term exposure to room temperature. After the bacterial solution begins to melt, use a sterile inoculation loop to dip a small amount of the bacterial solution in a sterile operating table and inoculate it into a conical flask containing 100 mL of the culture medium. Subsequently, place the conical flask in a constant temperature shaker at 30 °C with a rotation speed of 180 rpm and culture for about 12 - 16 h to promote the bacteria to enter the logarithmic growth phase.

[0075] (3) Prepare LB solid medium with the following nutritional components (1.0 L): 15 g agar, 10 g tryptone, 5 g yeast extract, and 10 g sodium chloride. Also perform sterilization treatment. After sterilization is completed, cool the medium to about 50 °C and pour it into a sterile petri dish in a sterile operation bench until it solidifies. When there is obvious growth of bacteria in the liquid medium, inoculate it onto the solid medium (plate streaking method) in a sterile operation bench. Place the petri dish in a 30 °C biochemical incubator and incubate it in the dark for 20 h. Subsequently, place the plate in a 4 °C refrigerator for cold storage, which can be stored for 1 week. Use a sterile inoculation loop to pick a single colony of MR-1 in a sterile operation bench and inoculate it into a conical flask containing 100 mL of culture solution. Culture it to the logarithmic growth phase under constant temperature shaking conditions (30 °C, 180 rpm), which takes about 12 - 16 h. Centrifuge the intensively cultured bacterial solution to obtain bacterial strain precipitate. Wash the centrifuged bacterial strain 3 - 4 times with piperazine-1,4-diethanesulfonic acid (PIPES) buffer with a pH of 7.0. Finally, disperse the washed bacterial strain in PIPES buffer, shake well, and adjust the OD 600 of the bacterial solution to 0.1.

[0076] 3. Extraction and determination of ferrous iron

[0077] Shake the sample in the vial well, pipette 0.2 mL of the sample suspension into 0.2 mL of hydrochloric acid, and shake and extract it at a rate of 180 rpm under dark room temperature conditions for 60 min. After the extraction is completed, centrifuge it, pipette 0.2 mL of the supernatant, add 0.4 mL of sodium acetate buffer and 0.1 mL of o-phenanthroline color reagent, and perform color development in the dark for 10 min. Then measure the absorbance of the sample at a wavelength of 510 nm, and calculate the actual concentration of ferrous iron in the sample based on the ferrous iron calibration curve.

[0078] Test Example 1

[0079] Add 50 mL of experimental solution into a 100 mL vial to construct a microcosm culture system. The experimental solution includes: PIPES buffer, ferrihydrite suspension, and sodium lactate. Among them, the concentration of the ferrihydrite suspension is 200 mg / L, and the concentration of sodium lactate is 5 mmol / L. Add the carbon-based material 1 prepared in Example 1 into the vials of the test group, and only add the bacterial solution in the control group. The concentration of the carbon-based material 1 in the test group is 0.8 g / L, and the initial content of microorganisms is about 10 7 cells / L. Ensure that the initial concentrations of the test group and the control group are the same based on the protein content. Place the control group and the test group in a constant temperature shaking incubator at 30 °C and a rotation speed of 180 rpm for culture, and measure the ferrous iron concentration at the 0th, 6th, 12th, 24th, 48th, 72nd, and 96th h of the reaction.

[0080] Figure 5 is the kinetic curve of the formation of Fe(II) in the form of hydrochloric acid extract during the reduction stage in Test Example 1. FromFigure 5 It can be seen that in the control group with only the addition of strains, the reduction rate of ferrihydrite is slow. After 48 h of reaction, the content of ferrous iron extracted by hydrochloric acid tends to be balanced, and after 96 h of reaction, the content of ferrous iron extracted by hydrochloric acid is only 60.78 mg / L, accounting for only 30.39% of the total amount of ferrihydrite. In the test group with the addition of carbon-based material 1, the reduction rate of ferrihydrite is fast. After 6 h of reaction, the content of ferrous iron extracted by hydrochloric acid tends to be balanced, and after 96 h of reaction, the content of ferrous iron extracted by hydrochloric acid is 69.78 mg / L, accounting for 34.89% of the total amount of ferrihydrite. The results of the kinetic experiment show that in the test group with the addition of carbon-based material 1 and the control group with only the addition of bacterial solution, the reduction rate of ferrihydrite is significantly different, and carbon-based material 1 can effectively promote the reduction process of ferrihydrite.

[0081] Test Example 2

[0082] Add 50 mL of experimental solution into a 100 mL vial to construct a microcosm culture system. The experimental solution includes: PIPES buffer solution, ferrihydrite suspension and sodium lactate. Among them, the concentration of the ferrihydrite suspension is 200 mg / L, and the concentration of sodium lactate is 5 mmol / L. Add the carbon-based material 2 prepared in Example 2 into the vials of the test group, and only add the bacterial solution into the control group. The concentration of carbon-based material 2 in the test group is 0.8 g / L, and the initial content of microorganisms is about 10 7 cells / L, and the initial concentrations of the test group and the control group are ensured to be the same based on the protein content. Place the control group and the test group in a constant temperature shaker at 30 °C and a rotation speed of 180 rpm for cultivation, and measure the ferrous iron concentration at the 0th, 6th, 12th, 24th, 48th, 72nd and 96th h of the reaction.

[0083] Figure 6 is the kinetic curve of the formation of ferrous iron extracted by hydrochloric acid in the reduction stage in Test Example 2. It can be seen from Figure 6 It can be seen that in the control group with only the addition of strains, the reduction rate of ferrihydrite is slow. After 48 h of reaction, the content of ferrous iron extracted by hydrochloric acid tends to be balanced, and after 96 h of reaction, the content of ferrous iron extracted by hydrochloric acid is only 60.78 mg / L, accounting for only 30.39% of the total amount of ferrihydrite. In the test group with the addition of carbon-based material 2, the reduction rate of ferrihydrite is fast. After 6 h of reaction, the content of ferrous iron extracted by hydrochloric acid tends to be balanced, and after 96 h of reaction, the content of ferrous iron extracted by hydrochloric acid is 65.07 mg / L, accounting for 32.54% of the total amount of ferrihydrite. The results of the kinetic experiment show that in the test group with the addition of carbon-based material 2 and the control group with only the addition of bacterial solution, the reduction rate of ferrihydrite is significantly different, and carbon-based material 2 can effectively promote the reduction process of ferrihydrite.

[0084] Test Example 3

[0085] The rice pot experiment was carried out in a greenhouse. The specific steps are as follows:

[0086] (1) Seedling raising: Select an appropriate amount of plump and evenly sized rice seeds (Huanghuazhan), place them in a clean beaker, dry them at 42 °C for 2 - 3 days to break dormancy, then wash them. Next, soak the seeds in 30% H2O2 for 10 min for disinfection, and rinse them multiple times with ultrapure water until thoroughly clean. Add a certain amount of nutrient solution for seedling raising. After three weeks of hydroponic growth, select seedlings of uniform size for the experiment;

[0087] (2) Soil flooding and seedling transplantation: Each single pot (diameter 25 cm; height 35 cm) is filled with 5 kg of soil, add 3 L of water, and let it stabilize for 2 - 3 days. Then transplant the seedlings into the pots, with 5 seedlings as a group, and plant 3 groups in each pot;

[0088] (3) Rice flooding stage: Under natural conditions, flood and irrigate with deionized water, do not apply fertilizers during this period, and keep the water depth in each pot at 5 cm above the soil surface; Add 0.5 g of carbon-based material 1 to experimental group 1, add 0.5 g of carbon-based material 2 to experimental group 2, the concentration of the carbon-based materials is about 0.1 g / kg, and the control group is not treated;

[0089] (4) Seven sampling points were set according to the growth cycle of rice (seedling emergence stage, tillering stage, jointing stage, booting stage, heading stage, flowering stage, and filling and maturity stage). Soil samples and pore water solutions were collected on the 0th, 15th, and 30th days of the flooding stage. After filtering a part of the pore water solution with a 0.45 μm filter membrane, the dissolved organic carbon content (DOC) in the soil was measured using a total organic carbon analyzer. After filtering a part of the pore water solution with a 0.22 μm filter membrane, it was used to measure the content of water-soluble ferrous iron in the soil.

[0090] Figure 7 For the kinetic curve of Fe(II) extracted by hydrochloric acid in the reduction stage in Test Example 3, where, Figure 7 (a) is the kinetic curve of Fe(II) extracted by hydrochloric acid in the reduction stage for experimental group 1 and the control group, Figure 7 (b) is the kinetic curve of Fe(II) extracted by hydrochloric acid in the reduction stage for experimental group 2 and the control group. It can be seen that after 30 days of cultivation, the content of ferrous iron extracted by hydrochloric acid in the control group is only 1.74 g / kg, while in experimental groups 1 and 2 with the addition of carbon-based material 1 and carbon-based material 2, the contents of ferrous iron extracted by hydrochloric acid are 5.74 g / kg and 5.86 g / kg respectively, indicating that carbon-based materials 1 and 2 can significantly promote the reduction and dissolution of iron minerals in the soil. Figure 7

[0091] Figure 8 For the kinetic curve of DOC in the reduction stage in Test Example 3, where, Figure 8 (a) is the kinetic curve of DOC in the reduction stage for experimental group 1 and the control group, Figure 8(b) is the kinetic curve of DOC in the reduction stage of experimental group 2 and the control group. As can be seen from Figure 8 , after 30 days of cultivation, in the control group, the content of dissolved organic carbon was 23.75 mg / L, while in experimental groups 1 and 2 with the addition of carbon-based material 1 and carbon-based material 2, the contents of dissolved organic carbon were 29.76 mg / L and 33.58 mg / L respectively, indicating that the addition of carbon-based materials can improve soil fertility to a certain extent and promote plant growth.

[0092] The carbon-based material provided by the present invention can effectively promote soil carbon sequestration and the reduction and dissolution of minerals, realize the activation of mineral elements, and is beneficial to the absorption of mineral elements by crops. In addition to promoting the reduction and activation of iron elements in the soil, it also has great application potential for the activation of various mineral nutrient elements such as selenium, zinc, and calcium.

Claims

1. A carbon-based material, characterized in that: The carbon-based material is lignin surface-modified with anthraquinone-2-carboxylic acid.

2. The carbon-based material according to claim 1, characterized in that The mass ratio of the anthraquinone-2-carboxylic acid to the lignin is 1: (0.5-25)。 3. The carbon-based material according to claim 1 or 2, characterized in that: The carbon-based material includes the following preparation raw materials: Lignin, anthraquinone-2-carboxylic acid, solvent, catalyst and dehydrating agent.

4. The carbon-based material according to claim 3, characterized in that The mass ratio of the lignin, the catalyst and the dehydrating agent is 1000:(2-60):(40-800).

5. The carbon-based material according to claim 3, characterized in that The catalyst includes 4-dimethylaminopyridine; and / or, the dehydrating agent comprises dicyclohexylcarbodiimide; And / or, the solvent comprises a C1-C2 chloroalkane.

6. The method for preparing a carbon-based material according to any one of claims 3 to 5, characterized in that: The following steps are involved: S1, adding lignin and anthraquinone-2-carboxylic acid into a reaction device, introducing an inert gas, adding a solvent, and obtaining a mixed solution; S2. Mix the catalyst, dehydrating agent and solvent, add them into the mixed liquid, react and obtain the carbon-based material.

7. The preparation method according to claim 6, characterized in that: In the step S1, the solid-liquid ratio of the lignin to the solvent is 1 g: (2-30) mL; And / or, in step S2, the solid-liquid ratio of the catalyst to the solvent is (0.2-10) mg:1 mL; And / or, in step S2, the reaction time is 24-96h.

8. Use of the carbon-based material according to any one of claims 1 to 5 in soil improvement.

9. The use according to claim 8, characterized in that: The soil improvement is to reduce and activate the mineral elements in the soil; The mineral elements include iron, selenium, zinc and calcium.

10. The use according to claim 9, characterized in that: The amount of the carbon-based material used is (0.1-1.5) g / kg soil.

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