Highly biocompatible carbon materials, methods of making and using the same

Abstract

The present application relates to the technical field of water treatment, and discloses a high-biological-affinity carbon material with weak surface electronegativity, good hydrophilicity and easy microbial biofilm formation, and a preparation method and application thereof.The preparation method comprises the following steps: (1) loading iron salt on biomass powder to obtain a first precursor; (2) adding the first precursor into a gel solution containing sodium alginate, urea, phytic acid and thiourea to obtain a second precursor; (3) adding the second precursor dropwise into a calcium chloride solution for solidification to obtain a third precursor; (4) performing freeze-drying treatment on the third precursor to obtain a fourth precursor; (5) performing heat treatment on the fourth precursor in an inert atmosphere to obtain a fifth precursor; (6) performing surface oxidation treatment on the fifth precursor to obtain a sixth precursor; (7) adding the sixth precursor into a MES buffer solution and reacting with EDC and NHS to obtain a seventh precursor; and (8) adding a chitosan-acetic acid mixed solution to the seventh precursor to obtain the high-biological-affinity carbon material.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and more specifically, to highly biocompatible carbon materials, their preparation methods, and applications. Background Technology

[0002] Currently, wastewater treatment is mainly divided into three categories: physical, chemical, and biological methods. Among them, biological methods are widely used due to their advantages such as low cost and good efficiency. Many researchers have derived various forms of wastewater treatment processes from the most basic biological method, the activated sludge process. The biofilm method is one such method, possessing advantages such as strong adaptability, high efficiency, low residual sludge production, and convenient operation and management. The biofilm method mainly involves setting up a carrier (i.e., packing material) in the wastewater treatment structure for the growth and aggregation of microorganisms. Microorganisms accumulate and attach to the surface of the carrier to form a biofilm. When oxygenated wastewater flows through the carrier at a certain flow rate, the microorganisms in the biofilm absorb and decompose the organic matter in the water, purifying the wastewater. Simultaneously, the microorganisms proliferate, and the biofilm thickens. When the biofilm grows to a certain thickness, the diffusion of oxygen into the interior of the biofilm is restricted. The surface remains aerobic, while the inner layer becomes anoxic or even anaerobic, eventually leading to the detachment of the biofilm. Subsequently, new biofilm will continue to grow on the carrier surface, repeating the cycle and purifying the wastewater. The carrier plays a supporting role in the biofilm process and is crucial to the efficiency of the process; therefore, its selection is of paramount importance.

[0003] Biochar materials, as carriers, can provide habitats for microorganisms and effectively increase their abundance and enrichment of related functional strains. They can also promote electron transfer in microbial biochemical processes, thereby enhancing their biochemical activity. Simultaneously, the dissolved organic matter slowly released from their surface can serve as nutrients for microorganisms. However, the adhesion of microorganisms to the carrier is usually influenced by the carrier's surface properties, including surface electronegativity and hydrophilicity. Generally, microbial surfaces are mostly negatively charged, and char materials are also typically negatively charged; therefore, microbial adhesion to char materials may be "repelled." Furthermore, the hydrophilicity or hydrophobicity of the carrier surface is a crucial factor affecting microbial adhesion and fixation strength. Stronger surface hydrophilicity results in better adhesion performance, providing ample opportunity for bacteria in aqueous solutions to contact and fix on the surface, which is beneficial for forming a thicker and more uniform biofilm. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a highly biocompatible carbon material with weak surface electronegativity, good hydrophilicity, and easy biofilm formation by microorganisms, as well as its preparation method and application. The technical solution is as follows:

[0005] A method for preparing highly biocompatible carbon materials includes the following steps:

[0006] (1) Iron salts were loaded onto biomass powder to obtain the first precursor;

[0007] (2) The first precursor was added to a gel solution containing sodium alginate, urea, phytic acid and thiourea to obtain the second precursor;

[0008] (3) The second precursor was added dropwise to a calcium chloride solution for solidification to obtain the third precursor;

[0009] (4) The third precursor was freeze-dried to obtain the fourth precursor;

[0010] (5) The fourth precursor was heat-treated in an inert atmosphere to obtain the fifth precursor;

[0011] (6) The fifth precursor is subjected to surface oxidation treatment to obtain the sixth precursor;

[0012] (7) The sixth precursor was added to the MES buffer, and then EDC and NHS were added for a light-protected reaction to obtain the seventh precursor;

[0013] (8) Add chitosan-acetic acid mixed solution to the seventh precursor and continue the reaction in the dark. After the reaction is completed, take out the solid and wash and dry it to obtain a carbon material with high biocompatibility.

[0014] As a further improvement to the above preparation method: Step (1) is to add biomass powder to a 0.5-1.5M ferric chloride solution at a solid-liquid ratio of 1g:(15-25mL), stir for 1-3 hours at room temperature, sonicate for 20-60 minutes, and evaporate at 40-70℃ to dryness to obtain the first precursor.

[0015] As a further improvement to the above preparation method: in step (2), urea, phytic acid and thiourea are added to the sodium alginate solution, and the first precursor is added after dissolution; the concentration of the sodium alginate solution is 0.01-0.03 g / mL, and 5-7 g of urea, 2-8 mL of 50% phytic acid solution, 1-5 g of thiourea and 5-15 g of the first precursor are added to every 100 mL of sodium alginate solution.

[0016] As a further improvement to the above preparation method: in step (3), the concentration of calcium chloride solution is 0.01-0.05 g / mL, and the curing time is 2-6 hours.

[0017] As a further improvement to the above preparation method: in step (5), the heat treatment is to heat to 600-900°C and hold for 1-3 hours under a nitrogen or argon atmosphere.

[0018] As a further improvement to the above preparation method: In step (6), the fifth precursor is first dispersed in water to form a 100 mL dispersion with a concentration of 5-30 mg / mL, then 50-150 mL of sodium hypochlorite solution with an effective chlorine content of 5% is added, and finally acetic acid is added until the pH is 4-5. The reaction is carried out at room temperature for 2-4 hours. After the reaction is completed, the solid is taken out and washed and dried to obtain the sixth precursor.

[0019] As a further improvement to the above preparation method: in step (7), 1-3g of the sixth precursor, 300-500mg of EDC and 200-300mg of NHS are added to every 100ml of LMES buffer, and the mixture is stirred at room temperature in the dark for 0.5-2 hours.

[0020] As a further improvement to the above preparation method: In step (8), the volume ratio of the seventh precursor to the chitosan-acetic acid solution is (1-3):1, the concentration of chitosan in the mixed solution is 5-20 mg / mL, the volume fraction of acetic acid is 0.5-3%, the reaction is carried out at room temperature in the dark for 12-36 hours, the solid is washed with hydrochloric acid solution, deionized water and ethanol in sequence, and then freeze-dried to obtain a carbon material with high biocompatibility.

[0021] The highly biocompatible carbon material was prepared by the above-described preparation method.

[0022] The wastewater treatment method utilizes a highly biocompatible carbon material prepared by the above-described preparation method.

[0023] The advantages of the high biocompatibility carbon material, its preparation method, and its application of the present invention are as follows:

[0024] First, through steps such as loading iron salts onto biomass, gel solidification, and freeze-drying, a stable three-dimensional porous network structure is formed in the material. The hierarchical pores not only increase the specific surface area but also significantly enhance the contact opportunities between the material and microorganisms, providing excellent physical support for microbial attachment, growth, and diffusion. The connectivity and openness of the pore structure allow microorganisms to smoothly enter the material's interior and form a uniformly distributed biofilm, laying the structural foundation for efficient wastewater treatment and biocatalysis.

[0025] Subsequently, through heat treatment under an inert atmosphere and mild liquid-phase oxidation, the oxygen-containing groups, nitrogen-containing groups, and other active functional groups on the material surface are redistributed and directionally exposed, gradually modulating its surface charge from a strongly negative state to a weakly negative state. This avoids strong repulsion while maintaining interfacial stability and the structural integrity of the material in an aquatic environment. Therefore, compared with ordinary carbon materials, the material of this invention exhibits a higher initial microbial adhesion rate and a significantly faster biofilm initiation speed.

[0026] More importantly, this invention, through EDC / NHS activation reaction and chitosan grafting or coating, further enhances the material surface's electronegativity, hydrophilicity, and biocompatibility. Chitosan, as a natural polysaccharide, possesses excellent hydrophilicity; its introduction makes the material surface highly wettable, allowing water molecules to spread rapidly, significantly reducing interfacial energy and contact resistance. This not only promotes easier microbial adhesion but also facilitates the diffusion of nutrients, substrates, and electron donors, improving microbial activity on the material. Simultaneously, chitosan's weak positive charge gently modulates the overall surface charge, resulting in a mild interfacial electrical pattern that transitions from weakly negative to near-neutral or even slightly positive. This not only promotes initial cell adsorption but also enhances biofilm stability, making it less prone to detachment during long-term operation. Furthermore, chitosan's biocompatibility further strengthens the chemical affinity between microorganisms and the material interface, resulting in a more uniform, dense, and highly active biofilm.

[0027] In summary, the preparation method of the present invention is simple and easy to implement. Through the synergistic effect of structural regulation, surface functionalization and interfacial electrical adjustment, the carbon material obtained in the end exhibits outstanding performance in terms of weak surface electronegativity, significant hydrophilicity and extremely high microbial biofilm formation efficiency, giving the material excellent biocompatibility and making it of great application value in water treatment, biofilm reactors and biological carriers.

[0028] The embodiments of the invention provided in this specification will be further described below with reference to specific implementation methods. Additional aspects and advantages of the embodiments of the invention provided in this specification will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the embodiments of the invention provided in this specification. Detailed Implementation

[0029] To make the technical solution of the present invention clearer, the present invention will now be further described in conjunction with embodiments. The embodiments of the present invention are only used to illustrate the technical content of the present invention and are not intended to limit the present invention. Any equivalent substitutions, conventional adjustments, or functional changes made to materials, parameters, conditions, or steps based on the disclosure of this specification, as long as they do not deviate from the core idea of ​​the present invention, should be considered to fall within the protection scope of the present invention.

[0030] It should be noted that the technical features described in the different embodiments of this specification can be freely combined to form new implementation methods, provided that they do not conflict and are technically feasible. Other alternative embodiments, variations, or structural adjustments that can be obtained by those skilled in the art under the guidance of this invention should also be included within the scope of protection of this invention.

[0031] Furthermore, the terms "comprising," "including," and "having," as used in this specification and claims, are non-exclusive terms, indicating that the described element may further include other elements not explicitly listed. Unless otherwise stated, the experimental conditions, types of materials, proportions, temperatures, and equipment mentioned in this specification may be appropriately adjusted according to specific needs without affecting the substantive content of the invention.

[0032] Based on the above principles, the preparation method and related technical effects of the present invention will be further described below with reference to specific embodiments, but should not be construed as limiting the present invention.

[0033] Example 1

[0034] The preparation method of the high biocompatibility carbon material in this embodiment includes the following steps:

[0035] (1) Fresh and dried bamboo powder was added to 1M ferric chloride solution at a solid-liquid ratio of 1g:20mL, stirred at room temperature for 2 hours, sonicated for 30 minutes, and then evaporated at 50℃ to dryness to obtain the first precursor.

[0036] (2) According to the ratio of 6g urea, 5mL phytic acid solution with a mass fraction of 50%, 3g thiourea and 10g first precursor added to 100mL sodium alginate solution, urea, phytic acid and thiourea are added to sodium alginate solution with a concentration of 0.02g / mL. After dissolution, the first precursor is added and stirred to form a homogeneous mixture, which is the gel-like second precursor.

[0037] (3) The second precursor was added to a calcium chloride solution with a concentration of 0.03 g / mL for 4 hours for solidification. After removing the gel ball, it was washed 5 times with deionized water to obtain the third precursor.

[0038] (4) The third precursor was freeze-dried to obtain the fourth precursor.

[0039] (5) The fourth precursor was heat-treated in an inert atmosphere at a temperature of 750°C for 2 hours to obtain the fifth precursor.

[0040] (6) First, disperse the fifth precursor in water to form a 100 mL dispersion with a concentration of 20 mg / mL. Then, add 100 mL of sodium hypochlorite solution with an effective chlorine content of 5%. Finally, add acetic acid until the pH is 4.5. React at room temperature for 3 hours. After the reaction is complete, take out the solid and wash the solid with deionized water until the filtrate is close to neutral. Dry it at 60°C for 12 hours to obtain the sixth precursor.

[0041] (7) According to the ratio of 2g of the sixth precursor, 400mg of EDC and 250mg of NHS per 100ml of MES buffer, the sixth precursor was first added to the MES buffer and ultrasonically dispersed for 15 minutes. Then, EDC and NHS were added, and the mixture was stirred and reacted at room temperature in the dark for 1 hour to obtain the liquid seventh precursor. Among them, EDC is 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and NHS is N-hydroxysuccinimide.

[0042] (8) Add a chitosan-acetic acid mixed solution to the seventh precursor. The volume ratio of the seventh precursor to the chitosan-acetic acid solution is 2:1. The concentration of chitosan in the mixed solution is 15 mg / mL and the volume fraction of acetic acid is 2%. Stir the mixture at room temperature in the dark for 24 hours. After the reaction is complete, take out the solid and wash it five times with 0.1 M hydrochloric acid solution, deionized water and ethanol respectively. After freeze-drying, a highly biocompatible carbon material is obtained.

[0043] The carbon material in this embodiment had an average surface Zeta potential of -11.4 mV, an equilibrium water content of 11.58%, a biofilm content of 205.1 mg / g, a protein content of 22.43 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.51 × 10⁻⁶. 9 CFU / g.

[0044] Example 2

[0045] Compared with Example 1, the difference in the preparation method of the high biocompatibility carbon material in this example is that in step (2), the concentration of sodium alginate solution is 0.01g / mL, according to the ratio of 5g urea, 2mL phytic acid solution with a mass fraction of 50%, 1g thiourea and 5g first precursor added to every 100mL sodium alginate solution.

[0046] The carbon material in this embodiment was tested and found to have an average surface Zeta potential of -12.58 mV, an equilibrium water content of 10.95%, a biofilm content of 195.8 mg / g, a protein content of 21.56 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.25 × 10⁻⁶. 9 CFU / g.

[0047] Example 3

[0048] Compared with Example 1, the difference in the preparation method of the high biocompatibility carbon material in this example is that in step (2), according to the ratio of 7g urea, 8mL phytic acid solution with a mass fraction of 50%, 5g thiourea and 15g first precursor added to every 100mL sodium alginate solution, the concentration of sodium alginate solution is 0.03g / mL.

[0049] The carbon material in this embodiment was tested and found to have an average surface Zeta potential of -12.13 mV, an equilibrium water content of 10.53%, a biofilm content of 196.2 mg / g, a protein content of 21.18 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.12 × 10⁻⁶. 9 CFU / g.

[0050] Example 4

[0051] Compared with Example 1, the preparation method of the high biocompatibility carbon material in this example is different in that: in step (6), the fifth precursor is dispersed in water to form a 100mL dispersion with a concentration of 5mg / mL, and 50mL sodium hypochlorite solution is added, and the reaction is carried out at room temperature for 2 hours.

[0052] The carbon material in this embodiment had an average surface Zeta potential of -13.85 mV, an equilibrium water content of 9.88%, a biofilm content of 195.4 mg / g, a protein content of 20.91 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.05 × 10⁻⁶. 9 CFU / g.

[0053] Example 5

[0054] Compared with Example 1, the preparation method of the high biocompatibility carbon material in this example is different in that: in step (6), the fifth precursor is dispersed in water to form a 100 mL dispersion with a concentration of 30 mg / mL, and 150 mL of sodium hypochlorite solution is added, and the reaction is carried out at room temperature for 4 hours.

[0055] The carbon material in this embodiment had an average surface Zeta potential of -9.15 mV, an equilibrium water content of 9.52%, a biofilm content of 194.9 mg / g, a protein content of 20.85 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.01 × 10⁻⁶. 9 CFU / g.

[0056] Example 6

[0057] Compared with Example 1, the difference in the preparation method of the high bioaffinity carbon material in this example is that in step (7), 3g of the sixth precursor, 500mg of EDC and 300mg of NHS are added to every 100mMLMES buffer.

[0058] The carbon material in this embodiment was tested and found to have an average surface Zeta potential of -11.89 mV, an equilibrium water content of 11.21%, a biofilm content of 201.7 mg / g, a protein content of 21.98 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.33 × 10⁻⁶. 9 CFU / g.

[0059] Example 7

[0060] Compared with Example 1, the difference in the preparation method of the high bioaffinity carbon material in this example is that in step (7), 1g of the sixth precursor, 300mg of EDC and 200mg of NHS are added to every 100mMLMES buffer.

[0061] The carbon material in this embodiment was tested and found to have an average surface Zeta potential of -12.05 mV, an equilibrium water content of 11.15%, a biofilm formation rate of 198.6 mg / g, a protein content of the resuspended bacterial solution of 21.55 mg / g, and a fixed viable bacterial count of 6.24 × 10⁻⁶. 9 CFU / g.

[0062] Example 8

[0063] Compared with Example 1, the preparation method of the high biocompatibility carbon material in this example is different in that: the volume ratio of the seventh precursor to the chitosan-acetic acid solution is 3:1; the concentration of chitosan in the mixed solution is 20 mg / mL, and the volume fraction of acetic acid is 3%.

[0064] The carbon material in this embodiment was tested and found to have an average surface Zeta potential of -10.95 mV, an equilibrium water content of 11.87%, a biofilm content of 215.3 mg / g, a protein content of 23.54 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.89 × 10⁻⁶. 9 CFU / g.

[0065] Example 9

[0066] Compared with Example 1, the preparation method of the high biocompatibility carbon material in this example is different in that: the volume ratio of the seventh precursor to the chitosan-acetic acid solution is 1:1; the concentration of chitosan in the mixed solution is 5 mg / mL, and the volume fraction of acetic acid is 0.5%.

[0067] The carbon material in this embodiment was tested and found to have an average surface Zeta potential of -12.86 mV, an equilibrium water content of 11.35%, a biofilm content of 202.4 mg / g, a protein content of 22.10 mg / g in the resuspended bacterial solution, and a fixed viable bacterial count of 6.40 × 10⁻⁶. 9 CFU / g.

[0068] Compare with Example 1

[0069] Compared with Example 1, the difference in the preparation method of the carbon material in this comparative example is that step (1) was not performed.

[0070] The tests showed that the average surface Zeta potential of the carbon material in this control example was -22.80 mV, the equilibrium water content was 6.85%, the biofilm content was 58.2 mg / g, the protein content of the resuspended bacterial solution was 6.55 mg / g, and the number of immobilized viable bacteria was 1.53 × 10⁻⁶. 9 CFU / g.

[0071] Compare with Example 2

[0072] Compared with Example 1, the difference in the preparation method of the carbon material in this comparative example is that step (6) was not performed.

[0073] The tests showed that the average surface Zeta potential of the carbon material in this control example was -28.93 mV, the equilibrium water content was 5.82%, the biofilm content was 43.1 mg / g, the protein content of the resuspended bacterial solution was 4.58 mg / g, and the number of immobilized viable bacteria was 9.86 × 10⁻⁶. 8 CFU / g.

[0074] Compare with Example 3

[0075] Compared with Example 1, the preparation method of the carbon material in this comparative example is different in that: under a nitrogen atmosphere, fresh and dry bamboo powder is placed in a tube furnace, heated to 600°C at a heating rate of 10°C / min and held at that temperature for 2 hours, and then naturally cooled to room temperature; the material is taken out and placed in deionized water to stand for 30 minutes, the supernatant is poured off, and this step is repeated until the supernatant is close to neutral; then it is dried in an oven at 105°C for 12 hours, and after drying, it is ground to a particle size of 8-12 mesh to obtain the carbon material.

[0076] The tests showed that the average surface Zeta potential of the carbon material in this control example was -34.72 mV, the equilibrium water content was 4.51%, the biofilm content was 19.2 mg / g, the protein content of the resuspended bacterial solution was 1.95 mg / g, and the number of immobilized viable bacteria was 8.95 × 10⁻⁶. 6 CFU / g.

[0077] In the above performance tests, the average surface zeta potential was obtained by measuring the zeta potential and nanoparticle size analyzer using an Anton Paar Litesizer 500.

[0078] After drying the material in a 120℃ oven to constant weight, transfer it directly to a desiccator containing silica gel at the bottom until cooled. Remove and weigh immediately, recording the weight as m0. Then place the material in a sealed container with a saturated ammonium sulfate solution at the bottom. After 48 hours, remove and weigh immediately, recording the weight as m1. Equilibrium moisture content = (m1 - m0) / m0 × 100%.

[0079] The prepared bacterial suspension was mixed with the spiked wastewater at a 1:1 ratio and poured into an Erlenmeyer flask. Materials were added, and the flask was continuously aerated using an air pump. Biofilm formation was carried out under continuous aeration for 24 hours. Afterward, the flask was removed, dried in an oven at 105℃ for 2 hours, and weighed, recorded as m2. Biofilm formation amount = (m2 - m0) / m0.

[0080] The material was placed in the prepared bacterial suspension and agitated to adsorb and immobilize the microorganisms for 24 hours. After washing three times with phosphate-buffered saline (PBS), the material was transferred to a 50 mL sterile centrifuge tube, and 20 mL of PBS was added. The centrifuge tube was then capped and vortexed for 1 min, followed by sonication at 120 W for 15 min, and then vortexed for 1 min to detach the immobilized bacteria and obtain a resuspended bacterial solution. The resuspended bacterial solution was heated at 90 °C for 5 min to promote complete cell lysis. Total protein (PN) was measured using a Bioharp BL521A BCA protein assay kit. The protein content of the resuspended bacterial solution was calculated as PN / m0.

[0081] The material was placed in the prepared bacterial suspension and agitated to adsorb and immobilize microorganisms for 24 hours. After washing three times with phosphate-buffered saline (PBS), the material was placed in a 50 mL sterile centrifuge tube, and 20 mL of PBS was added. The centrifuge tube was then capped and vortexed for 1 min, followed by sonication at 120 W for 15 min, and then vortexed for 1 min to detach the immobilized bacteria and obtain a resuspended bacterial solution. A certain volume of the resuspended bacterial solution was transferred to agar solid medium for culture, and the colonies were counted to reflect the number of viable bacteria immobilized in the material. The method was performed in accordance with the Chinese National Standard "Determination of Total Colony Count" (GB4789.2—2016).

[0082] The embodiments of the high biocompatibility carbon material of the present invention are prepared by the preparation method described in any of the above embodiments.

[0083] An embodiment of the wastewater treatment method of the present invention is a highly biocompatible carbon material prepared by the preparation method described in any of the above embodiments.

[0084] The embodiments of the invention provided in this specification have been described above. Those skilled in the art will be able to implement the embodiments of the invention provided in this specification based on these descriptions. All other preferred embodiments and implementations obtained by those skilled in the art based on the above description of the embodiments of the invention provided in this specification without inventive effort should fall within the protection scope of the embodiments of the invention provided in this specification.

Claims

1. A method for preparing highly biocompatible carbon materials, characterized in that: Includes the following steps: (1) Iron salts were loaded onto biomass powder to obtain the first precursor; (2) The first precursor was added to a gel solution containing sodium alginate, urea, phytic acid and thiourea to obtain the second precursor; (3) The second precursor was added dropwise to a calcium chloride solution for solidification to obtain the third precursor; (4) The third precursor was freeze-dried to obtain the fourth precursor; (5) The fourth precursor was heat-treated in an inert atmosphere to obtain the fifth precursor; (6) The fifth precursor is subjected to surface oxidation treatment to obtain the sixth precursor; (7) The sixth precursor was added to the MES buffer, and then EDC and NHS were added for a light-protected reaction to obtain the seventh precursor; (8) Add chitosan-acetic acid mixed solution to the seventh precursor and continue the reaction in the dark. After the reaction is completed, take out the solid and wash and dry it to obtain a carbon material with high biocompatibility.

2. The preparation method according to claim 1, characterized in that: Step (1) is as follows: add biomass powder to 0.5-1.5M ferric chloride solution at a solid-liquid ratio of 1g:(15-25mL), stir at room temperature for 1-3 hours, sonicate for 20-60 minutes, and evaporate at 40-70℃ to dryness to obtain the first precursor.

3. The preparation method according to claim 1, characterized in that: In step (2), urea, phytic acid, and thiourea are added to the sodium alginate solution. After dissolution, the first precursor is added. The concentration of the sodium alginate solution is 0.01-0.03 g / mL. 5-7 g of urea, 2-8 mL of 50% phytic acid solution, 1-5 g of thiourea, and 5-15 g of the first precursor are added to every 100 mL of sodium alginate solution.

4. The preparation method according to claim 1, characterized in that: In step (3), the concentration of calcium chloride solution is 0.01 to 0.05 g / mL, and the curing time is 2 to 6 hours.

5. The preparation method according to claim 1, characterized in that: In step (5), the heat treatment involves heating to 600–900°C under a nitrogen or argon atmosphere and holding at that temperature for 1–3 hours.

6. The preparation method according to claim 1, characterized in that: In step (6), the fifth precursor is first dispersed in water to form a 100 mL dispersion with a concentration of 5-30 mg / mL. Then, 50-150 mL of sodium hypochlorite solution with an effective chlorine content of 5% is added. Finally, acetic acid is added until the pH is 4-5. The reaction is carried out at room temperature for 2-4 hours. After the reaction is completed, the solid is taken out and washed and dried to obtain the sixth precursor.

7. The preparation method according to claim 1, characterized in that: In step (7), 1-3g of the sixth precursor, 300-500mg of EDC and 200-300mg of NHS are added to every 100ml of LMES buffer, and the mixture is stirred at room temperature in the dark for 0.5-2 hours.

8. The preparation method according to claim 7, characterized in that: In step (8), the volume ratio of the seventh precursor to the chitosan-acetic acid solution is (1-3):

1. The concentration of chitosan in the mixed solution is 5-20 mg / mL, and the volume fraction of acetic acid is 0.5-3%. The mixture is stirred and reacted at room temperature in the dark for 12-36 hours. The solid is washed with hydrochloric acid solution, deionized water, and ethanol in sequence. After freeze-drying, a highly biocompatible carbon material is obtained.

9. A highly biocompatible carbon material, characterized in that: It is prepared by the preparation method according to any one of claims 1-8.

10. A wastewater treatment method, characterized in that: High biocompatibility carbon material prepared by the preparation method described in any one of claims 1-8.