Method for repairing phosphorus-polluted water body by using modified biochar

Abstract

The invention relates to the technical field of phosphorus adsorption, in particular to a method for repairing a phosphorus-polluted water body by using modified biochar, and the modified biochar is prepared from the following raw materials in parts by weight: 50-78 parts of a composite material, 15-36 parts of modified montmorillonite, 12-25 parts of modified carbon aerogel and 30-50 parts of a compound microorganism bacterium solution. The composite material comprises biochar, alkali-leached diatomite, ferrous salt, ferric salt and calcium salt, wherein the molar ratio of the biochar to the alkali-leached diatomite to the ferrous salt to the ferric salt to the calcium salt is (3-8): (2-5): (2-3): (1-2): 1. According to the prepared modified biochar, biochar is cooperated through multiple technologies, and the adsorption performance, the functional diversity, the environmental adaptability and the sustainability of the modified biochar are remarkably superior to those of traditional biochar.

Description

Technical Field

[0001] This invention relates to the field of water remediation technology, and more specifically, to a method for remediating phosphorus-polluted water bodies using modified biochar. Background Technology

[0002] Phosphorus is the controlling factor for eutrophication in most lakes and freshwater systems. When the total phosphorus concentration in water exceeds a certain range, it causes eutrophication, leading to the failure of water body functions and further impacting sustainable economic and social development. Therefore, finding effective methods to remove phosphorus from water is urgent. Currently, commonly used phosphorus removal methods mainly include chemical precipitation, biological methods, and adsorption methods. Among them, adsorption methods have received widespread attention due to their high efficiency, simple operation, and lack of secondary pollution. For adsorption methods, the choice of adsorbent is crucial to the phosphorus removal effect. Currently, materials for phosphorus adsorption mainly include fly ash, steel slag, and activated alumina. However, these raw materials are expensive, and phosphorus is difficult to desorb. Although steel slag and fly ash are inexpensive, these industrial wastes can leach harmful ions into the water.

[0003] Biochar is a carbon-rich product obtained by pyrolyzing biomass (straw, livestock manure, and other agricultural and forestry waste) under limited oxygen conditions at relatively low temperatures (<700℃). As a porous material, biochar has a large specific surface area and is an excellent adsorbent, attracting increasing attention from researchers for its application as an adsorbent in water treatment. However, current research reports on the adsorption of heavy metals and organic matter in water by biochar are numerous, while research on the adsorption of phosphorus in water is scarce. my country has abundant biochar raw materials, and utilizing these agricultural and forestry wastes can achieve the goal of "treating waste with waste." Simultaneously, biochar is also a good soil conditioner; therefore, returning biochar with adsorbed phosphorus to the soil has the dual effect of increasing soil fertility and improving soil quality. Traditional Chinese medicine is one of China's traditional industries, producing a large amount of prepared Chinese medicines annually, while also generating a considerable amount of medicinal residue. Statistics show that my country's annual discharge of plant-based medicinal residue alone reaches over 650,000 tons. Medicinal residue is generally a wet material, easily perishable, and has an unpleasant odor. After being transported out of the factory area, the residue from traditional Chinese medicine is often piled up and disposed of, which can easily cause serious pollution to the surrounding environment.

[0004] Currently, in the process of adsorbing phosphorus into water, raw biochar typically carries a negative surface charge, resulting in electrostatic repulsion with phosphate ions (anions). This leads to weak phosphorus adsorption capacity and may even result in negative adsorption. Biochar is easily washed away and broken in actual water bodies, leading to material loss and the risk of secondary release. Regenerating phosphorus-adsorbed biochar is difficult; while acid hydrolysis (such as with dilute H₂SO₄) can desorb phosphorus, it damages the carbon structure, reducing its reusability. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for remediating phosphorus-polluted water bodies using modified biochar.

[0006] In a first aspect, the present invention provides a modified biochar, which is made from the following raw materials in parts by weight: 50-78 parts of composite material, 15-36 parts of modified montmorillonite, 12-25 parts of modified carbon aerogel, and 30-50 parts of composite microbial inoculum. The composite material includes biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferrous salt, and calcium salt, wherein the molar ratio of the biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferrous salt, and calcium salt is 3~8:2~5:2~3:1~2:1.

[0007] Preferably, the ferrous salt is selected from at least one of ferrous sulfate, ferrous chloride, ferrous fumarate, ferrous oxalate, and ferrous lactate; the ferric salt is selected from at least one of ferric chloride, ferric sulfate, ferric citrate, ferric phosphate, and ferric nitrate; and the calcium salt is selected from at least one of calcium carbonate, calcium sulfate, calcium chloride, dicalcium phosphate, and tricalcium phosphate.

[0008] Preferably, the modified montmorillonite is prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite is 1-3:5-8.

[0009] Preferably, the modified carbon aerogel is prepared by sol-gelling resorcinol and formaldehyde monomer solutions to obtain an aerogel, followed by the addition of sodium hydroxide solution.

[0010] Preferably, the mass ratio of resorcinol to formaldehyde monomer is 3-5:1-2.

[0011] Preferably, the amount of sodium hydroxide solution added is 5% to 10%.

[0012] Preferably, the composite microbial culture includes heavy metal resistant bacteria Ralstonia and Bacillus, and the mass ratio of Ralstonia to Bacillus is 2-5:1-3.

[0013] Preferably, the heavy metal resistant bacterium Ralstonia has the accession number CGMCC1.1807, and the Bacillus has the accession number CICC 10268.

[0014] Secondly, the present invention provides an application of modified biochar, wherein the modified biochar is used to remediate phosphorus-polluted water bodies, comprising the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

[0015] In summary, the present invention has the following beneficial effects: 1. In this invention, modified biochar is prepared by combining composite materials, modified montmorillonite, modified carbon aerogel, and composite microbial inoculum. The combination of modified montmorillonite and biochar forms a stable nanostructure, improving the material's anti-aging properties and mechanical strength, making it suitable for wastewater treatment. The modified carbon aerogel further optimizes the three-dimensional porous network, enhancing the adsorption capacity for pollutants in wastewater. The composite microbial inoculum provides an environment for functional microbial communities, improving their survival rate and metabolic activity in polluted environments, thus strengthening the bioremediation effect.

[0016] 2. In this invention, the composite material contains biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt. This provides the biochar with a high specific surface area and abundant pore structure, enhancing its physical and chemical adsorption properties. After alkaline treatment, the alkali-impregnated diatomaceous earth exposes more silanol groups (Si-OH) and negatively charged surfaces, enhancing its electrostatic adsorption and ion exchange capabilities. The synergistic effect of alkali-impregnated diatomaceous earth and biochar, combined with the mineral structure of diatomaceous earth, significantly increases the number of oxygen-containing functional groups (carboxyl or hydroxyl groups) and cation exchange capacity, thus improving the adsorption capacity for heavy metal pollutants. Ferric salt can co-precipitate with biochar to form iron oxides on the biochar-diatomaceous earth surface, providing additional adsorption sites and enhancing the adsorption of anionic pollutants through surface complexation and electrostatic attraction. Ferrous salt, under alkaline conditions, can generate magnetic iron nanoparticles, facilitating adsorbent recovery and converting high-valence heavy metals into low-toxicity forms through reduction, thus improving the selectivity of adsorption performance. Ferrous salts can also interact with diatomaceous earth. The iron salts embed into the pores of the diatomaceous earth, reducing pore blockage. Simultaneously, the silanol groups of diatomaceous earth form Fe-O-Si bonds with iron ions, stabilizing the active sites of iron. The addition of calcium salts enables efficient capture of phosphates, fluorides, and some heavy metals through ion exchange and precipitation reactions. Calcium salts can also synergistically interact with biochar. Calcium ions can modify the surface of biochar, increasing alkaline sites and promoting precipitation reactions. At the same time, the porous structure of biochar provides a dispersion carrier for calcium salts, preventing aggregation and improving reaction efficiency. Calcium salts can also synergistically interact with iron salts, Ca... 2+ It works together with iron oxides to form a complex precipitate, further enhancing the fixation of phosphorus pollutants.

[0017] 3. The composite material in this invention includes biochar, alkali-impregnated diatomaceous earth, ferrous salts, ferric salts, and calcium salts. Biochar itself possesses a high specific surface area and abundant mesoporous structure, providing numerous adsorption sites and a supporting framework. The porosity of alkali-impregnated diatomaceous earth is further enhanced after alkali treatment, resulting in a more uniform pore size distribution and a significant increase in the overall specific surface area of ​​the material, thus improving its ability to capture liquid-phase pollutants. The combination of alkali-impregnated diatomaceous earth and biochar after alkali treatment forms a highly porosity, highly supportive system, ensuring uniform dispersion of subsequent metal salts and preventing agglomeration.

[0018] 4. In this invention, modified montmorillonite is prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide. The cationic groups of the modified montmorillonite modify the surface of biochar through electrostatic interaction, introducing alkyl chains to form mixed micelles, which enhances the electrostatic attraction to positively charged pollutants. The combined use of modified montmorillonite and biochar significantly improves adsorption performance and chemical stability. Modified carbon aerogel is prepared by sol-gelling resorcinol and formaldehyde monomer solutions to obtain an aerogel, and then adding sodium hydroxide solution. The carboxyl and hydroxyl functional groups on the surface of biochar can synergistically interact with the active sites of the modified carbon aerogel, enhancing the catalytic degradation ability of pollutants, especially in the adsorption of heavy metals and the treatment of organic pollutants.

[0019] 5. The modified biochar prepared in this invention combines biochar with composite materials, improving the mechanical strength and structural stability of the materials. The modified carbon aerogel and biochar possess high specific surface area and nanoscale pores, significantly enhancing the remediation capacity for phosphorus-contaminated water. The modified biochar and composite microbial solution can be coupled, offering the dual advantages of biochar enhancement and microbial enhancement. This not only improves the fermentation efficiency of the composite microbial solution but also enhances the tolerance of the microbial system to adverse environments. Through the synergistic effect of the modified biochar and composite microbial solution, further improvements are achieved in adsorption performance, functional diversity, environmental adaptability, and sustainability.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the scope of protection of the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are carried out according to conventional conditions or the conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments can be obtained from commercially available sources.

[0022] Example Example 1 A modified biochar is made from the following raw materials in parts by weight: 50 parts of composite material, 15 parts of modified montmorillonite, 12 parts of modified carbon aerogel, and 30 parts of composite microbial inoculum.

[0023] The composite material includes biochar, alkaline-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt, wherein the molar ratio of the biochar, alkaline-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt is 3:2:2:1:1.

[0024] Ferrous salts are selected from ferrous sulfate, ferric salts are selected from ferric chloride, and calcium salts are selected from calcium carbonate.

[0025] Modified montmorillonite was prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite was 1:5.

[0026] The modified carbon aerogel was prepared by sol-gelling resorcinol and formaldehyde monomer solution to obtain an aerogel, and then adding sodium hydroxide solution; the mass ratio of resorcinol to formaldehyde monomer was 3:1; and the amount of sodium hydroxide solution added was 5%.

[0027] The compound microbial culture includes heavy metal resistant bacteria Ralstonia and Bacillus, with a mass ratio of 2:1.

[0028] An application of modified biochar, and a method for remediating phosphorus-contaminated water bodies using modified biochar, comprising the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

[0029] Example 2 A modified biochar is made from the following raw materials in parts by weight: 55 parts of composite material, 18 parts of modified montmorillonite, 14 parts of modified carbon aerogel, and 35 parts of composite microbial inoculum.

[0030] The composite material includes biochar, alkaline-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt, wherein the molar ratio of the biochar, alkaline-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt is 3:2:2:1:1.

[0031] Ferrous salts are selected from ferrous sulfate, ferric salts are selected from ferric chloride, and calcium salts are selected from calcium carbonate.

[0032] Modified montmorillonite was prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite was 2:5.

[0033] The modified carbon aerogel was prepared by sol-gelling resorcinol and formaldehyde monomer solution to obtain an aerogel, and then adding sodium hydroxide solution; the mass ratio of resorcinol to formaldehyde monomer was 4:1; and the amount of sodium hydroxide solution added was 7%.

[0034] The compound microbial culture solution includes heavy metal resistant bacteria Ralstonia and Bacillus, with a mass ratio of 3:1.

[0035] An application of modified biochar, and a method for remediating phosphorus-contaminated water bodies using modified biochar, comprising the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

[0036] Example 3 A modified biochar is made from the following raw materials in parts by weight: 61 parts of composite material, 21 parts of modified montmorillonite, 18 parts of modified carbon aerogel, and 38 parts of composite microbial inoculum.

[0037] The composite material includes biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt, wherein the molar ratio of biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt is 5:3:2:1:1.

[0038] Ferrous salts are selected from ferrous sulfate, ferric salts are selected from ferric chloride, and calcium salts are selected from calcium carbonate.

[0039] Modified montmorillonite was prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite was 2:5.

[0040] The modified carbon aerogel was prepared by sol-gelling resorcinol and formaldehyde monomer solution to obtain an aerogel, and then adding sodium hydroxide solution; the mass ratio of resorcinol to formaldehyde monomer was 3:2; and the amount of sodium hydroxide solution added was 8%.

[0041] The compound microbial culture solution includes heavy metal resistant bacteria Ralstonia and Bacillus, with a mass ratio of 3:2.

[0042] An application of modified biochar, and a method for remediating phosphorus-contaminated water bodies using modified biochar, comprising the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

[0043] Example 4 A modified biochar is made from the following raw materials in parts by weight: 65 parts of composite material, 28 parts of modified montmorillonite, 18 parts of modified carbon aerogel, and 42 parts of composite microbial inoculum.

[0044] The composite material includes biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt, wherein the molar ratio of biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt is 5:3:2:1:1.

[0045] Ferrous salts are selected from ferrous sulfate, ferric salts are selected from ferric chloride, and calcium salts are selected from calcium carbonate.

[0046] Modified montmorillonite is prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite is 1-3:5-8.

[0047] The modified carbon aerogel was prepared by sol-gelling resorcinol and formaldehyde monomer solution to obtain an aerogel, and then adding sodium hydroxide solution; the mass ratio of resorcinol to formaldehyde monomer was 4:1; and the amount of sodium hydroxide solution added was 8%.

[0048] The compound microbial culture solution includes heavy metal resistant bacteria Ralstonia and Bacillus, with a mass ratio of 3:1.

[0049] An application of modified biochar, and a method for remediating phosphorus-contaminated water bodies using modified biochar, comprising the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

[0050] Example 5 A modified biochar is made from the following raw materials in parts by weight: 72 parts of composite material, 32 parts of modified montmorillonite, 22 parts of modified carbon aerogel, and 45 parts of composite microbial inoculum.

[0051] The composite material includes biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt, wherein the molar ratio of the biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt is 7:5:2:1:1.

[0052] Ferrous salts are selected from ferrous sulfate, ferric salts are selected from ferric chloride, and calcium salts are selected from calcium carbonate.

[0053] Modified montmorillonite was prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite was 3:7.

[0054] The modified carbon aerogel was prepared by sol-gelling resorcinol and formaldehyde monomer solutions, followed by the addition of sodium hydroxide solution; the mass ratio of resorcinol to formaldehyde monomer was 5:1; and the amount of sodium hydroxide solution added was 8%.

[0055] The compound microbial culture solution includes heavy metal resistant bacteria Ralstonia and Bacillus, with a mass ratio of 4:1.

[0056] An application of modified biochar, and a method for remediating phosphorus-contaminated water bodies using modified biochar, comprising the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

[0057] Example 6 A modified biochar is made from the following raw materials in parts by weight: 78 parts of composite material, 36 parts of modified montmorillonite, 25 parts of modified carbon aerogel, and 50 parts of composite microbial inoculum.

[0058] The composite material includes biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt, wherein the molar ratio of the biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferric salt, and calcium salt is 8:5:3:2:1.

[0059] Ferrous salts are selected from ferrous sulfate, ferric salts are selected from ferric chloride, and calcium salts are selected from calcium carbonate.

[0060] Modified montmorillonite was prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite was 3:8.

[0061] The modified carbon aerogel was prepared by sol-gelling resorcinol and formaldehyde monomer solutions, followed by the addition of sodium hydroxide solution; the mass ratio of resorcinol to formaldehyde monomer was 5:2; and the amount of sodium hydroxide solution added was 10%.

[0062] The compound microbial culture solution includes heavy metal resistant bacteria Ralstonia and Bacillus, with a mass ratio of 5:3.

[0063] An application of modified biochar, and a method for remediating phosphorus-contaminated water bodies using modified biochar, comprising the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

[0064] Comparative Example 1 The difference between this comparative example and Example 1 is that no composite material was added.

[0065] Comparative Example 2 The difference between this comparative example and Example 1 is that no modified montmorillonite was added.

[0066] Comparative Example 3 The difference between this comparative example and Example 1 is that no modified carbon aerogel was added.

[0067] Comparative Example 4 The difference between this comparative example and Example 1 is that no compound microbial culture solution was added.

[0068] Table 1 compares the adsorption effects on phosphorus-containing wastewater under different pH conditions.

[0069] The above description is merely an exemplary embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A modified biochar, characterized in that, It is made from the following raw materials in parts by weight: 50-78 parts of composite material, 15-36 parts of modified montmorillonite, 12-25 parts of modified carbon aerogel, and 30-50 parts of composite microbial inoculum. The composite material includes biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferrous salt, and calcium salt, wherein the molar ratio of the biochar, alkali-impregnated diatomaceous earth, ferrous salt, ferrous salt, and calcium salt is 3~8:2~5:2~3:1~2:

1.

2. The modified biochar according to claim 1, characterized in that, The modified montmorillonite was prepared by modifying montmorillonite with hexadecyltrimethylammonium bromide, wherein the mass ratio of hexadecyltrimethylammonium bromide to montmorillonite was 1-3:5-8.

3. The modified biochar according to claim 1, characterized in that, The modified carbon aerogel is prepared by sol-gelling of resorcinol and formaldehyde monomer solutions, followed by the addition of sodium hydroxide solution.

4. The modified biochar according to claim 3, characterized in that, The mass ratio of resorcinol to formaldehyde monomer is 3-5:1-2.

5. The modified biochar according to claim 1, characterized in that, The ferrous salt is selected from at least one of ferrous sulfate, ferrous chloride, ferrous fumarate, ferrous oxalate, and ferrous lactate; the ferric salt is selected from at least one of ferric chloride, ferric sulfate, ferric citrate, ferric phosphate, and ferric nitrate.

6. The modified biochar according to claim 1, characterized in that, The calcium salt is selected from at least one of calcium carbonate, calcium sulfate, calcium chloride, dicalcium phosphate, and tricalcium phosphate.

7. The modified biochar according to claim 3, characterized in that, The amount of sodium hydroxide solution added is 5% to 10%.

8. The modified biochar according to claim 1, characterized in that, The composite microbial culture includes heavy metal resistant bacteria Ralstonia and Bacillus, with a mass ratio of Ralstonia to Bacillus of 2–5:1–3.

9. The modified biochar according to claim 1, characterized in that, The heavy metal-resistant bacterium Ralstonia has the accession number CGMCC 1.1807, and the Bacillus has the accession number CICC10268.

10. The application of the modified biochar according to any one of claims 1 to 9, characterized in that, The modified biochar remediation method for phosphorus-polluted water includes the following steps: (1) Mix the water-absorbing resin particles and the modified biochar, and then screen out the modified biochar containing water-absorbing resin particles to obtain modified composite biochar balls. (2) The modified composite biochar balls were mixed with the composite microbial liquid to prepare the composite adsorbent; (3) Add the composite adsorbent to the water to be treated, stir and shake it thoroughly, and then filter it to obtain the treated water.

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