A biochar composite adsorbent material for efficiently removing pollutants from water and its preparation method

Abstract

This application belongs to the technical field of biochar adsorption materials, specifically providing a biochar composite adsorption material for efficiently removing pollutants from water and its preparation method. The biochar composite adsorption material for efficiently removing pollutants from water comprises: a porous biochar matrix; ZnAl-LDH loaded on the porous biochar matrix; and a cyclodextrin derivative bound to the ZnAl-LDH and / or the porous biochar matrix, wherein the cyclodextrin derivative comprises a supramolecular complex of tannic acid and aminocyclodextrin; the tannic acid and aminocyclodextrin self-assemble to form the supramolecular complex through intermolecular hydrogen bonds and host-guest interactions. The adsorption material prepared in this application has the advantage of multiple adsorption of metal ions and organic pollutants.

Description

Technical Field

[0001] This application belongs to the field of biochar adsorption material technology, and in particular relates to a biochar composite adsorption material for efficiently removing pollutants from water and its preparation method. Background Technology

[0002] With the rapid development of industry and agriculture, large quantities of complex wastewater containing heavy metals, eutrophic substances, and recalcitrant organic matter are being discharged, posing a serious threat to water environment safety and human health. Adsorption methods are an important technology in water treatment due to their simple operation, controllable cost, and low risk of secondary pollution. Biochar, a porous carbon material obtained from the pyrolysis of biomass under limited oxygen conditions, possesses a well-developed pore structure, high specific surface area, and abundant oxygen-containing functional groups, exhibiting certain adsorption potential for heavy metal ions and some organic matter. Layered double hydroxides (LDHs), such as zinc aluminum hydrotalcite, exhibit excellent affinity for oxygen-containing anions such as phosphate and chromate due to their unique layered structure and anion exchange capacity. Theoretically, combining biochar with LDH can leverage their synergistic effect to achieve the simultaneous removal of multiple pollutants.

[0003] However, existing biochar / LDH composite systems still face key bottlenecks in practical applications: low adsorption capacity for organic pollutants and the inability to achieve in-situ degradation or transformation of enriched organic matter without the addition of external oxidants and energy. Chemically, the interaction between biochar and LDH surfaces and organic molecules relies primarily on relatively weak forces such as π-π stacking, hydrophobic partitioning, and hydrogen bonding, lacking stronger specific adsorption sites and chemical transformation active centers. Existing improvement approaches mainly focus on introducing photocatalytic semiconductors (such as TiO2) to activate light and generate active free radicals, or loading transition metals to activate external oxidants such as persulfate. Photocatalysis requires high light transmittance from the water body, making it difficult to treat high-turbidity wastewater; persulfate activation requires continuous addition of oxidants and carries the risk of metal leaching. A few studies have attempted to introduce redox groups such as quinone / hydroquinone onto the material surface, but these have limited functionality, and their efficiency in enriching and degrading organic matter needs further improvement, failing to achieve effective synergy with the chelation removal of heavy metal ions.

[0004] Therefore, there is an urgent need and significant application value to develop an environmentally friendly biochar / LDH composite material that can achieve efficient adsorption and in-situ oxidation of organic matter and synergistic enhancement of heavy metal chelation. Summary of the Invention

[0005] To address the aforementioned issues, this application provides a biochar composite adsorbent material for efficiently removing pollutants from water and its preparation method.

[0006] This application first provides a biochar composite adsorbent material for efficiently removing pollutants from water, characterized in that it comprises: Porous biochar matrix; ZnAl-LDH loaded on the porous biochar matrix; and cyclodextrin derivatives bound to the ZnAl-LDH and / or the porous biochar matrix, wherein the cyclodextrin derivatives comprise a supramolecular complex of tannic acid and aminocyclodextrin; wherein the tannic acid and aminocyclodextrin self-assemble to form the supramolecular complex through intermolecular hydrogen bonds and host-guest interactions.

[0007] Furthermore, the aminated cyclodextrin is selected from mono-(6-ethylenediamino-6-deoxy)-β-cyclodextrin, mono-(6-diethylenetriamino-6-deoxy)-β-cyclodextrin, or any combination thereof.

[0008] Furthermore, the mass ratio of the tannic acid to the aminocyclodextrin is 1:(0.7-1.35).

[0009] Furthermore, the mass ratio of the tannic acid to the aminocyclodextrin is 1:(0.75-1.2).

[0010] Furthermore, the porous biochar matrix is ​​derived from at least one of rice straw, corn straw, reed straw, wheat straw, and sawdust.

[0011] Furthermore, the porous biochar matrix is ​​doped with calcium and phosphorus, and at least a portion of the calcium and phosphorus exists in the form of amorphous calcium phosphate and / or hydroxyapatite.

[0012] Furthermore, based on the total weight of the biochar composite adsorbent material, the content of the functional organic component is 5-25 wt%, the content of ZnAl-LDH is 15-50 wt%, and the remainder is the porous biochar matrix.

[0013] This application provides a method for preparing a biochar composite adsorbent material for efficiently removing pollutants from water, comprising the following steps: 1) Provide porous biochar; dissolve soluble zinc salt and soluble aluminum salt in water to form a mixed salt solution, add the porous biochar to the solution, stir, and obtain a first dispersion; 2) Add a cyclodextrin derivative solution to the first dispersion and stir to obtain a second dispersion; wherein the cyclodextrin derivative solution contains tannic acid and aminocyclodextrin; while stirring, add an alkaline solution to the second dispersion to adjust the pH to 9.5-10.5, continue stirring to carry out a coprecipitation reaction to obtain a reaction mixture, age the reaction mixture at 70-90℃ for 12-72 hours, then perform solid-liquid separation, wash the solid product, and dry to obtain the final product.

[0014] Furthermore, the provision of porous biochar specifically includes: treating biomass raw materials with an impregnation solution containing calcium ions and phosphate ions, drying them to obtain a precursor; and pyrolyzing the precursor at 600-900℃ under an inert atmosphere to obtain the porous biochar.

[0015] More preferably, the pyrolysis temperature can be, for example, 600℃, 650℃, 700℃, 750℃, 800℃, 850℃, or 900℃, with 700-800℃ being the most desirable. Within this range, the aromatization degree and porosity of the biochar develop in a balanced manner, and an appropriate amount of oxygen-containing functional groups are retained on the surface, which is beneficial for subsequent loading.

[0016] Furthermore, the calcium ions are derived from one or more of calcium chloride, calcium nitrate, and calcium acetate, and the phosphate ions are derived from one or more of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and sodium phosphate; the molar ratio of calcium ions to phosphate ions is 1.5-1.8:1.

[0017] Furthermore, the cyclodextrin derivative solution is prepared by a method comprising the following steps: The tannic acid is dissolved in water to form the first solution; The amino-modified cyclodextrin is dissolved in water to form a second solution; The second solution is mixed with the first solution, stirred, and optionally the pH of the mixture is adjusted to 8.0-9.0.

[0018] Furthermore, the soluble zinc salt is zinc chloride, zinc nitrate, or zinc sulfate, and the soluble aluminum salt is aluminum chloride, aluminum nitrate, or aluminum sulfate; and the molar ratio of zinc ions to aluminum ions is 2.5-3.5:1.

[0019] More preferably, the zinc-aluminum molar ratio can be, for example, 2.5:1, 2.8:1, 3:1, 3.2:1, or 3.5:1. Generally, a ZnAl-LDH with good crystallinity and moderate anion exchange capacity can be obtained at a ratio of around 3:1.

[0020] This application provides the application of a biochar composite adsorbent material in the removal of pollutants from water, including heavy metal ions, phosphates, and organic pollutants.

[0021] Furthermore, the heavy metal ions are selected from at least one of lead ions, cadmium ions, copper ions, and chromium ions; the organic pollutants include at least one of antibiotics, dyes, and phenolic compounds.

[0022] Compared with the prior art, this application has the following beneficial effects: The porous biochar of this application provides a high specific surface area and abundant mass transfer channels, and is further doped with calcium and phosphorus, with at least some calcium and phosphorus distributed in the carbon framework in the form of amorphous calcium phosphate. This not only improves the pore structure distribution but also provides additional phosphate precipitation and removal sites and enhances the fixation of certain heavy metal ions. Furthermore, ZnAl-LDH captures anionic pollutants such as phosphate through interlayer anion exchange and can utilize its layer metal ions to participate in the surface precipitation of heavy metals. Moreover, the multi-component complex formed by tannic acid and aminocyclodextrin further enhances the adsorption capacity and resistance to ionic interference. Tannic acid can also undergo auto-oxidation, losing electrons to form semiquinone radicals and quinone structures, and transferring electrons to dissolved oxygen to generate superoxide radicals and hydrogen peroxide. These reactive oxygen species can attack organic pollutant molecules, achieving in-situ oxidative degradation, enabling simultaneous and deep purification of anionic and cationic pollutants and organic toxins in complex wastewater. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of nitrogen adsorption test data of the BJH adsorbent material in Example 1 of this application.

[0024] Figure 2 This is a schematic diagram of the nitrogen adsorption test data of the BJH adsorbent material in control group 1 of this application.

[0025] Figure 3 This is a schematic diagram of the nitrogen adsorption test data of the BJH adsorbent material in control group 2 of this application.

[0026] Figure 4 This is a schematic diagram of the TEM and EDS tests of biochar in Example 1 of this application. Detailed Implementation

[0027] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0030] The terms "preferred," "more preferably," "better," and "even better" used in this application refer to embodiments of this application that provide certain beneficial effects under certain circumstances. However, other embodiments may also be preferred under the same or other circumstances. Furthermore, the description of one or more preferred embodiments does not imply that other embodiments are unavailable, nor is it intended to exclude other embodiments from the scope of this application. That is, in this application, "preferred," "more preferably," "better," and "even better" are merely descriptions of implementations or embodiments with better effects, but do not constitute a limitation on the scope of protection of this application.

[0031] In this application, terms such as "further," "even more," and "particularly" are used for descriptive purposes and to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0032] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0033] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0034] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0035] In this application, "above" or "below" includes the number itself. For example, "below 1" includes 1.

[0036] In this application, room temperature refers to 0~40℃, including but not limited to 10~40℃, or further to 20~30℃.

[0037] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0038] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0039] Example 1

[0040] The preparation method of the biochar composite adsorbent material for efficiently removing pollutants from water in this embodiment includes the following steps: 1) Take rice straw, wash it with deionized water, dry it at 60℃, and then crush it through an 80-mesh sieve to obtain biomass substrate; add 0.5g carrageenan to 100mL saturated calcium chloride solution, mix thoroughly, add an equal volume of 4.2mmol dipotassium hydrogen phosphate solution, mix thoroughly, add 30g biomass substrate and mix thoroughly, stir and dry the resulting mixture, then pyrolyze it in a muffle furnace at 750℃ for 2h, cool it naturally, grind it through a 100-mesh sieve to obtain biochar for later use; 2) Accurately weigh 0.03 mol zinc chloride and 0.01 mol aluminum chloride hexahydrate and dissolve them in 100 mL of deionized water. Then add 3 g of biochar and stir vigorously for 10 min. Add 125 mL of cyclodextrin derivative solution and continue stirring for 20 min. Then adjust the pH to about 10 with 1 mol / L NaOH aqueous solution and continue stirring for 2 h. Then age at 80℃ for 48 h, centrifuge, wash the obtained solid with deionized water, dry at 60℃, and grind it through a 150 mesh sieve to obtain the final product.

[0041] The cyclodextrin derivative solution in this embodiment was prepared by the following steps: 2.0 g of tannic acid was accurately weighed and dissolved in 100 mL of deionized water. The solution was magnetically stirred at 300 rpm at room temperature until completely dissolved, yielding a pale yellow clear solution A. 1.5 g of mono-(6-ethylenediamino-6-deoxy)-β-cyclodextrin was accurately weighed and dissolved in 50 mL of deionized water, yielding a colorless and transparent solution B. Solution B was slowly added dropwise to solution A at room temperature and a stirring speed of 400 rpm. After the addition was complete, stirring was continued for 2 hours. Subsequently, the pH of the mixture was adjusted to 8.5 with 1 mol / L NaOH solution, and stirring was continued for 30 minutes to obtain the final solution.

[0042] Example 2

[0043] The preparation method of the biochar composite adsorbent material for efficiently removing pollutants from water in this embodiment includes the following steps: 1) Take rice straw, wash it with deionized water, dry it at 60℃, and then crush it through an 80-mesh sieve to obtain biomass substrate; add 0.5g carrageenan to 100mL saturated calcium chloride solution, mix thoroughly, add an equal volume of 4.2mmol dipotassium hydrogen phosphate solution, mix thoroughly, add 30g biomass substrate and mix thoroughly, stir and dry the resulting mixture, then pyrolyze it in a muffle furnace at 750℃ for 2h, cool it naturally, grind it through a 100-mesh sieve to obtain biochar for later use; 2) Accurately weigh 0.03 mol zinc chloride and 0.01 mol aluminum chloride hexahydrate and dissolve them in 100 mL of deionized water. Then add 3 g of biochar and stir vigorously for 10 min. Add 125 mL of cyclodextrin derivative solution and continue stirring for 20 min. Then adjust the pH to about 10 with 1 mol / L NaOH aqueous solution and continue stirring for 2 h. Then age at 80℃ for 48 h, centrifuge, wash the obtained solid with deionized water, dry at 60℃, and grind it through a 150 mesh sieve to obtain the final product.

[0044] The cyclodextrin derivative solution in this embodiment was prepared by the following steps: 1.5 g of tannic acid was accurately weighed and dissolved in 100 mL of deionized water. The solution was magnetically stirred at 300 rpm at room temperature until completely dissolved, yielding a pale yellow clear solution A. 2.0 g of mono-(6-ethylenediamino-6-deoxy)-β-cyclodextrin was accurately weighed and dissolved in 50 mL of deionized water, yielding a colorless and transparent solution B. Solution B was slowly added dropwise to solution A at room temperature and a stirring speed of 400 rpm. After the addition was complete, stirring was continued for 2 hours. Subsequently, the pH of the mixture was adjusted to 8.5 with 1 mol / L NaOH solution, and stirring was continued for 30 minutes to obtain the final solution.

[0045] Control group 1 The preparation method of the adsorbent material in this control group includes the following steps: 1) Take rice straw, wash it with deionized water, dry it at 60°C, then crush it through an 80-mesh sieve to obtain biomass base material, then pyrolyze it in a muffle furnace at 750°C for 2 hours, and after natural cooling, grind it through a 100-mesh sieve to obtain biochar for later use. 2) Accurately weigh 0.03 mol zinc chloride and 0.01 mol aluminum chloride hexahydrate and dissolve them in 100 mL of deionized water. Then add 3 g of biochar and stir vigorously for 10 min. Add 125 mL of cyclodextrin derivative solution and continue stirring for 20 min. Then adjust the pH to about 10 with 1 mol / L NaOH aqueous solution and continue stirring for 2 h. Then age at 80℃ for 48 h, centrifuge, wash the obtained solid with deionized water, dry at 60℃, and grind it through a 150 mesh sieve to obtain the final product.

[0046] The cyclodextrin derivative solution for this control group was prepared using the following steps: 2.0 g of tannic acid was accurately weighed and dissolved in 100 mL of deionized water. The solution was magnetically stirred at 300 rpm at room temperature until completely dissolved, yielding a pale yellow, clear solution A. 1.5 g of mono-(6-ethylenediamino-6-deoxy)-β-cyclodextrin was accurately weighed and dissolved in 50 mL of deionized water, yielding a colorless, transparent solution B. Solution B was slowly added dropwise to solution A at room temperature and a stirring speed of 400 rpm. After the addition was complete, stirring was continued for 2 hours. Subsequently, the pH of the mixture was adjusted to 8.5 with 1 mol / L NaOH solution, and stirring was continued for 30 minutes to obtain the final solution.

[0047] Control group 2 The preparation method of the adsorbent material in this control group includes the following steps: 1) Take rice straw, wash it with deionized water, dry it at 60℃, and then crush it through an 80-mesh sieve to obtain biomass substrate; add 0.5g carrageenan to 100mL saturated calcium chloride solution, mix thoroughly, add an equal volume of 4.2mmol dipotassium hydrogen phosphate solution, mix thoroughly, add 30g biomass substrate and mix thoroughly, stir and dry the resulting mixture, then pyrolyze it in a muffle furnace at 750℃ for 2h, cool it naturally, grind it through a 100-mesh sieve to obtain biochar for later use; 2) Accurately weigh 0.06 mol zinc chloride and 0.02 mol aluminum chloride hexahydrate and dissolve them in 100 mL of deionized water. Then add 3 g of biochar and stir vigorously for 30 min. Adjust the pH to about 10 with 1 mol / L NaOH aqueous solution and continue stirring for 2 h. Then age at 80℃ for 48 h, centrifuge to separate, wash the obtained solid with deionized water, dry at 60℃, and grind through a 150 mesh sieve to obtain the final product.

[0048] Control group 3 The preparation method of the adsorbent material in this control group includes the following steps: 1) Take rice straw, wash it with deionized water, dry it at 60℃, and then crush it through an 80-mesh sieve to obtain biomass substrate; add 0.5g carrageenan to 100mL saturated calcium chloride solution, mix thoroughly, add an equal volume of 4.2mmol dipotassium hydrogen phosphate solution, mix thoroughly, add 30g biomass substrate and mix thoroughly, stir and dry the resulting mixture, then pyrolyze it in a muffle furnace at 750℃ for 2h, cool it naturally, grind it through a 100-mesh sieve to obtain biochar for later use; 2) Accurately weigh 0.03 mol zinc chloride and 0.01 mol aluminum chloride hexahydrate and dissolve them in 100 mL of deionized water. Then add 3 g of biochar and stir vigorously for 10 min. Add 125 mL of tannic acid solution and continue stirring for 20 min. Then adjust the pH to about 10 with 1 mol / L NaOH aqueous solution and continue stirring for 2 h. Then age at 80℃ for 48 h, centrifuge to separate, wash the obtained solid with deionized water, dry at 60℃, and grind through a 150 mesh sieve to obtain the final product.

[0049] The tannic acid solution in this control group was prepared by the following steps: 2.0 g of tannic acid was accurately weighed and dissolved in 100 mL of deionized water. The solution was then magnetically stirred at 300 rpm at room temperature until it was completely dissolved, resulting in a pale yellow clear solution A.

[0050] Control group 4 The preparation method of the adsorbent material in this control group includes the following steps: 1) Take rice straw, wash it with deionized water, dry it at 60℃, and then crush it through an 80-mesh sieve to obtain biomass substrate; add 0.5g carrageenan to 100mL saturated calcium chloride solution, mix thoroughly, add an equal volume of 4.2mmol dipotassium hydrogen phosphate solution, mix thoroughly, add 30g biomass substrate and mix thoroughly, stir and dry the resulting mixture, then pyrolyze it in a muffle furnace at 750℃ for 2h, cool it naturally, grind it through a 100-mesh sieve to obtain biochar for later use; 2) Accurately weigh 0.03 mol zinc chloride and 0.01 mol aluminum chloride hexahydrate and dissolve them in 100 mL of deionized water. Then add 3 g of biochar and stir vigorously for 10 min. Add 125 mL of cyclodextrin derivative solution and continue stirring for 20 min. Then adjust the pH to about 10 with 1 mol / L NaOH aqueous solution and continue stirring for 2 h. Then age at 80℃ for 48 h, centrifuge, wash the obtained solid with deionized water, dry at 60℃, and grind it through a 150 mesh sieve to obtain the final product.

[0051] The cyclodextrin derivative solution of this control group was prepared by the following steps: 1.5 g of mono-(6-ethylenediamino-6-deoxy)-β-cyclodextrin was accurately weighed and dissolved in 50 mL of deionized water to obtain a colorless and transparent solution B.

[0052] Performance testing 1. Take the adsorbent materials from Examples 1-2 and Control Groups 1-4, and use Pb 2+ As a representative ion, with an initial concentration of 200 mg / L, pH=5.0, and an adsorbent dosage of 0.5 g / L, the adsorption capacity of the material was tested by shaking at 25℃ for 24 h. For total phosphorus, with an initial phosphorus concentration of 100 mg / L, pH=6.5, and an adsorbent dosage of 0.2 g / L, the adsorption capacity of the material was tested by shaking at 150 r / min for 24 h. Ciprofloxacin was used as a model organic compound, with an initial concentration of 50 mg / L, pH=6.0, and an adsorbent dosage of 0.5 g / L. The adsorption was conducted in the dark without any added oxidant, shaking at 25℃ for 24 h, and the ciprofloxacin concentration was measured and the total removal rate was calculated. The comprehensive test results are shown in Table 1.

[0053] Table 1. Comprehensive performance test data of the adsorbent materials in Examples 1-2 and Control Groups 1-4

[0054] 2. Take the adsorption materials from Example 1 and Control Groups 1-2, and perform BJH nitrogen adsorption tests. The test results are as follows: Figures 1-3 As shown.

[0055] 3. The biochar from Example 1 was subjected to TEM and EDS tests, and the results were... Figure 4As shown, it can be seen that amorphous calcium phosphate is uniformly distributed inside the microporous carbon material.

[0056] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A biochar composite adsorbent material for efficient removal of pollutants from water, characterized in that: Include: Porous biochar matrix; ZnAl-LDH loaded on the porous biochar matrix; and cyclodextrin derivatives bound to the ZnAl-LDH and / or the porous biochar matrix, wherein the cyclodextrin derivatives comprise a supramolecular complex of tannic acid and aminocyclodextrin; wherein the tannic acid and aminocyclodextrin self-assemble to form the supramolecular complex through intermolecular hydrogen bonds and host-guest interactions.

2. The biochar composite adsorbent material for efficient removal of pollutants from water according to claim 1, characterized in that: The aminated cyclodextrin is selected from mono-(6-ethylenediamino-6-deoxy)-β-cyclodextrin, mono-(6-diethylenetriamino-6-deoxy)-β-cyclodextrin, or any combination thereof.

3. The biochar composite adsorbent material for efficiently removing pollutants from water according to claim 1, characterized in that: The mass ratio of the tannic acid to the aminocyclodextrin is 1:(0.7-1.35).

4. The biochar composite adsorbent material for efficiently removing pollutants from water according to claim 1, characterized in that: The mass ratio of the tannic acid to the aminocyclodextrin is 1:(0.75-1.2).

5. The biochar composite adsorbent material for efficiently removing pollutants from water according to claim 1, characterized in that: The porous biochar matrix is ​​derived from at least one of rice straw, corn straw, reed straw, wheat straw, and sawdust.

6. The biochar composite adsorbent material for efficiently removing pollutants from water according to any one of claims 1-5, characterized in that: The porous biochar matrix is ​​doped with calcium and phosphorus, and at least a portion of the calcium and phosphorus exists in the form of amorphous calcium phosphate and / or hydroxyapatite.

7. The biochar composite adsorbent material for efficiently removing pollutants from water according to claim 6, characterized in that: Based on the total weight of the biochar composite adsorbent material, the content of the cyclodextrin derivative is 5-25 wt%, the content of the ZnAl-LDH is 15-50 wt%, and the balance is the porous biochar matrix.

8. A method for preparing a biochar composite adsorbent material for efficiently removing pollutants from water, characterized in that: Includes the following steps: 1) Provide porous biochar; dissolve soluble zinc salt and soluble aluminum salt in water to form a mixed salt solution, add the porous biochar to the solution, stir, and obtain a first dispersion; 2) Add a cyclodextrin derivative solution to the first dispersion and stir to obtain a second dispersion; wherein the cyclodextrin derivative solution contains tannic acid and aminocyclodextrin; while stirring, add an alkaline solution to the second dispersion to adjust the pH to 9.5-10.5, continue stirring to carry out a coprecipitation reaction to obtain a reaction mixture, age the reaction mixture at 70-90℃ for 12-72 hours, then perform solid-liquid separation, wash the solid product, and dry to obtain the final product.

9. The method for preparing the biochar composite adsorbent material for efficiently removing pollutants from water according to claim 8, characterized in that: The provision of porous biochar specifically includes: treating biomass raw materials with an impregnation solution containing calcium ions and phosphate ions, drying them to obtain a precursor; and pyrolyzing the precursor at 600-900℃ under an inert atmosphere to obtain the porous biochar.

10. The preparation method of the biochar composite adsorbent material for efficiently removing pollutants from water according to claim 8, characterized in that: The calcium ions are derived from one or more of calcium chloride, calcium nitrate, and calcium acetate, and the phosphate ions are derived from one or more of dipotassium hydrogen phosphate, potassium dihydrogen phosphate, and sodium phosphate; the molar ratio of calcium ions to phosphate ions is 1.5-1.8:1.

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