A conductive bio-hydrogel, its preparation method and application

Abstract

This invention discloses a conductive bio-hydrogel, its preparation method, and its application, belonging to the field of biomaterials technology. The invention uses anaerobic activated sludge, sodium alginate, polyvinyl alcohol, and carbon black as raw materials. These are injected into a boric acid-CaCl2-chitosan mixed solution using a syringe, and continuously stirred. The process utilizes CaCl2... 2+ Sodium alginate-Ca2+ via diffusion mechanism 2+ Cross-linking and a polyvinyl alcohol-boric acid polymer cross-linking network are used to obtain a conductive bio-hydrogel with uniform pore distribution and a multidimensional interpenetrating network structure. This invention encapsulates anaerobic activated sludge and carbon black in a hydrogel material, enhancing the anaerobic activated sludge's resistance to toxic environmental factors and achieving efficient biodegradation of recalcitrant pollutants.

Description

Technical Field

[0001] This invention relates to the field of biomaterials technology, and in particular to a conductive bio-hydrogel, its preparation method, and its application. Background Technology

[0002] Anaerobic biological technology is currently the mainstream wastewater treatment method for treating high-concentration industrial wastewater. However, this traditional method faces the following drawbacks: The co-treatment of high-concentration wastewater, such as pharmaceutical wastewater, and processes for generating green energy using anaerobic microorganisms typically requires a long start-up time for granulation, resulting in a lengthy granular sludge formation process; high-concentration pharmaceutical wastewater often presents a toxic environment with high antibiotic stress, making the activity of microorganisms in traditional granular sludge susceptible to wastewater fluctuations, and the activity of secreted enzymes in treating antibiotics unstable, making it difficult to maintain efficient wastewater treatment and energy conversion processes, and highlighting the difficulty in controlling microbial activity.

[0003] In recent years, research on the immobilization of microorganisms to form biogels based on the cross-linking effect of hydrophilic polymers has attracted widespread attention. The reaction of polymers with cross-linking agents can produce a network structure, which can encapsulate microorganisms within the gel network, thereby efficiently forming biogel particles similar to granular sludge. Currently, most research and applications of polymeric gel structures are concentrated in the biomedical field, and research on gel-anaerobic microorganism coupled water-energy regeneration technology has not yet been reported. Summary of the Invention

[0004] The primary objective of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a method for preparing conductive bio-hydrogels.

[0005] Another object of the present invention is to provide a conductive bio-hydrogel.

[0006] Another object of the present invention is to provide applications of the above-mentioned conductive biohydrogel.

[0007] This invention proposes encapsulating anaerobic microorganisms in a polymeric biogel structure to enhance their ability to inhibit and mitigate toxic agents. The conductive biogel prepared in this invention comprises a hydrogel with a multi-layered cross-linked network encapsulating anaerobic activated sludge and conductive carbon black; the cross-linked network includes sodium alginate-Ca... 2+ The conductive biogel provided by this invention utilizes physical cross-linking, a polymer network cross-linking of polyvinyl alcohol and boric acid, and the long-chain network of chitosan itself. It features rapid reaction initiation, short treatment cycle, and strong environmental adaptability, making it suitable for high-concentration wastewater treatment and providing technical support for relevant wastewater treatment policies and resource utilization.

[0008] The gel particles prepared by this invention can provide a favorable microenvironment and cover for the growth and enrichment of microorganisms, improving the retention rate, cell density, and resistance to toxicity of anaerobic microorganisms, thereby enhancing the microbial treatment effect. The anaerobic energy regeneration process carried out by the gel particles prepared by this invention is mainly completed collaboratively by three key microorganisms: hydrolytic acidifying bacteria, acetic acid-producing bacteria, and methanogenic bacteria. This involves reactions such as hydrolysis and acidification, hydrogen and acetic acid production, and methanogenesis. Hydrolytic acidifying bacteria degrade complex organic pollutants into simple organic compounds such as monosaccharides and amino acids through hydrolysis and fermentation. Subsequently, acetic acid-producing bacteria and other microorganisms decompose these simple organic compounds into small molecule products such as formic acid, acetic acid, H2, and CO2. Finally, methanogenic bacteria effectively convert these into methane (CH4), making it a renewable energy source.

[0009] Experimental results show that the conductive biogel prepared in this invention has good antibiotic degradation ability and can maintain high methanogenic activity under antibiotic inhibition conditions; the gel structure has good mechanical properties of resistance to external forces, such as compressive and tensile strength.

[0010] Specifically, the objective of this invention is achieved through the following technical solutions:

[0011] A method for preparing a conductive bio-hydrogel includes the following steps:

[0012] (1) Prepare an aqueous solution containing polyvinyl alcohol (PVA) and sodium alginate (SA), sterilize it, and mix it to obtain a PVA-SA mixed solution;

[0013] (2) Prepare an aqueous solution containing CaCl2, H3BO3 and chitosan (CS), adjust the pH of the solution to 5, and mix to obtain a CaCl2-H3BO3-CS mixed solution;

[0014] (3) Add the anaerobic activated sludge to the PVA-SA mixed solution prepared in step (1), add carbon black, mix and stir evenly to obtain a biomass solution;

[0015] (4) Use a syringe to draw up the biomass solution prepared in step (3) and evenly drop it into the CaCl2-H3BO3-CS mixed solution in step (2) to obtain the conductive biohydrogel.

[0016] Further, in the PVA-SA mixed solution described in step (1), the concentration of polyvinyl alcohol is 5 wt% to 10 wt%, preferably 7.5 wt% to 9 wt%, more preferably 7.5 wt%; and the concentration of sodium alginate is 0.5 wt% to 2 wt%, more preferably 1 wt%.

[0017] Further, the sterilization described in step (1) is high-pressure sterilization at 121°C for 60±10 minutes in an autoclave.

[0018] Further, in the CaCl2-H3BO3-CS mixed solution described in step (2), the concentration of CaCl2 is 1 wt% to 3 wt%, preferably 2 wt%; the concentration of the H3BO3 aqueous solution is 2 wt% to 4 wt%, preferably 3 wt%; and the concentration of chitosan is 0.05 wt% to 0.2 wt%, preferably 0.1 wt%.

[0019] Furthermore, the pH adjustment of the solution in step (2) is achieved using HCl.

[0020] Furthermore, the amount of anaerobic activated sludge added in step (3) is calculated based on its concentration in the system as 2 to 4 g / L, preferably based on its concentration in the system as 3 g / L.

[0021] Further, the amount of carbon black added in step (3) is calculated based on its concentration in the system of 0.5 to 2 g / L, preferably based on its concentration in the system of 1 g / L.

[0022] Furthermore, the needle diameter of the syringe described in step (4) is 3±0.5 mm.

[0023] Furthermore, the dripping rate described in step (4) is 100 ± 10 drops / min.

[0024] Furthermore, while the CaCl2-H3BO3-CS mixed solution is being added dropwise in step (4), it is rotated at a speed of 330-350 rpm.

[0025] A conductive bio-hydrogel is obtained by the above preparation method.

[0026] The above-mentioned conductive biohydrogels are used in wastewater treatment.

[0027] Furthermore, the wastewater contains COD and / or antibiotic drugs.

[0028] Furthermore, the concentration of COD is not less than 3 g / L.

[0029] Furthermore, the antibiotic drug mentioned includes sulfamethoxazole.

[0030] Furthermore, the concentration of sulfamethoxazole is not less than 6 mg / L.

[0031] This invention uses anaerobic activated sludge, sodium alginate (SA), polyvinyl alcohol (PVA), and carbon black as raw materials. The solution is injected into a boric acid-CaCl2-chitosan mixed solution using a 3 mm diameter syringe, and continuously stirred. The process utilizes Ca... 2+Sodium alginate-Ca ester with diffusion mechanism 2+ Cross-linking and a polyvinyl alcohol-boric acid polymer cross-linking network are used to obtain a conductive bio-hydrogel with uniform pore distribution and a multidimensional interpenetrating network structure. This invention encapsulates anaerobic activated sludge and carbon black in a hydrogel material, enhancing the anaerobic activated sludge's resistance to toxic environmental factors and achieving efficient biodegradation of recalcitrant pollutants.

[0032] The anaerobic energy regeneration process of the gel particles prepared in this invention is mainly completed by three key microorganisms: hydrolytic acidifying bacteria, acetic acid-producing bacteria, and methanogenic bacteria. It involves reactions such as hydrolysis and acidification, hydrogen and acetic acid production, and methanogenesis. Hydrolytic acidifying bacteria degrade complex organic pollutants into simple organic compounds such as monosaccharides and amino acids through hydrolysis and fermentation. Subsequently, acetic acid-producing bacteria and other microorganisms decompose the simple organic compounds into small molecule products such as formic acid, acetic acid, H2, and CO2. Finally, methanogenic bacteria effectively convert them into methane (CH4), which becomes a renewable energy source.

[0033] The present invention has the following advantages and effects compared with the prior art:

[0034] 1) The multidimensional interpenetrating network structure can effectively prevent toxic substances from directly contacting anaerobic microorganisms, thus protecting anaerobic activated sludge.

[0035] 2) Carbon black promotes anaerobic reactions and indirectly facilitates interspecies electron transfer, thereby promoting the degradation of COD and antibiotics and improving methanogenesis efficiency;

[0036] 3) The conductive bio-hydrogel constructs a reaction microenvironment containing carbon black, which helps the adsorption and degradation of antibiotic substances such as sulfamethoxazole (SMX) generated from pharmaceutical wastewater, etc.

[0037] 4) This gel technology has good biocompatibility and can be used not only in anaerobic processes, but also when the activated sludge is composed of other functional bacteria such as anaerobic ammonia oxidizing bacteria. Attached Figure Description

[0038] Figure 1 A schematic diagram of a conductive biogel encapsulating anaerobic sludge and carbon black based on a multidimensional interpenetrating network structure.

[0039] Figure 2 This is a flowchart of the preparation process for conductive biogels;

[0040] Figure 3 The cumulative methane production curve and the final production bar chart are shown.

[0041] Figure 4 COD degradation curves and degradation rate bar charts;

[0042] Figure 5The degradation curve and degradation rate bar chart for SMX are shown.

[0043] Figure 6 Cryo-scanning electron microscopy image of a 100 μm multidimensional interpenetrating network structure conductive biohydrogel;

[0044] Figure 7 Cryo-scanning electron microscopy image of a multidimensional interpenetrating network conductive biohydrogel at 10 μm (porosity changes).

[0045] Figure 8 Cryo-scanning electron microscopy image of a multidimensional interpenetrating network conductive biohydrogel at 10 μm (bacterial species changes).

[0046] Figure 9 Microscopic image of a section of gel containing 7.5% PVA and 1% SA;

[0047] Figure 10 Microscopic image of a section of gel containing 9% PVA and 1% SA;

[0048] Figure 11 Image of the gel prepared in Example 1;

[0049] Figure 12 This is a photograph of the gel prepared in Comparative Example 1. Detailed Implementation

[0050] The embodiments of the present invention will be described in detail below. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0051] The anaerobic activated sludge in the following examples came from the secondary sedimentation tank of the Qianshan Wastewater Treatment Plant. It contained a variety of anaerobic microorganisms, including hydrolytic acidifying bacteria, acetic acid-producing bacteria, and methanogenic bacteria.

[0052] The carbon black used in the following examples was purchased from STREM and had an average particle size of 9 μm.

[0053] The polyvinyl alcohol used in the following examples has a purity of 95% and a molecular weight of 89,000 to 98,000.

[0054] Unless otherwise specified, all percentages in the following examples are by mass percentages.

[0055] Example 1

[0056] (1) Solution preparation: First, prepare an aqueous solution containing 7.5% polyvinyl alcohol and 1% sodium alginate (SA), place it in an autoclave and autoclave at 121°C for 60 minutes, cool to room temperature, and mix to obtain a PVA-SA mixed solution; then prepare an aqueous solution containing 2% CaCl2, 3% H3BO3 and 0.1% chitosan (CS), and add HCl dropwise to make the pH of the solution 5. After mixing, dissolve by ultrasonication to obtain a CaCl2-H3BO3-CS mixed solution.

[0057] (2) Preparation of biomass solution: Wash the anaerobic activated sludge at least three times in influent with carbon source removed, then centrifuge at 7000 rpm for 2 minutes. The purpose of centrifugation is to remove the supernatant, thereby increasing the concentration of anaerobic activated sludge. Add the centrifuged anaerobic activated sludge at 3 g / L to the PVA-SA mixed solution, add 1 g / L of carbon black, and mix thoroughly to obtain the biomass solution. The stirring of the biomass solution should be slow to avoid entrapping air bubbles, which would affect the gel hardness. To maintain the anaerobic environment and the activity of anaerobic microorganisms, the preparation of the biomass solution should be carried out in an anaerobic operating table that is continuously filled with nitrogen.

[0058] (3) Preparation of biogel: Draw the biomass solution described in step (2) into a syringe, and then evenly drip it into the CaCl2-H3BO3-CS mixed solution described in step (1) using a specially made syringe needle with a diameter of about 3 mm. If the needle becomes clogged, it should be replaced in time. Each time the biomass solution is drawn with the syringe, it should be stirred slowly to ensure that the carbon black is mixed evenly. The syringe should be "low, edge, and uniform", that is, the distance between the needle and the liquid surface should be about 5 cm, the injection speed should be about 100 drops / min, and the injection should be made at the edge of the liquid surface. To prevent the beads from sticking together, while injecting at the edge of the liquid surface, the mixed solution should be rotated at a speed of 330-350 rpm, and the gel particles gathered in the center of the liquid surface should be dispersed from time to time. After the gel is prepared, it should be continuously reinforced in the CaCl2-H3BO3-CS mixed solution for 1 hour.

[0059] Furthermore, to ensure uniform injection, an autosampler can be constructed in conjunction with an inflation device, and the injection rate of the syringe can be controlled by adjusting a fixed gas flow rate.

[0060] (4) Gel curing: The hydrogel particles are soaked in a Na2SO4 mixed solution for curing. The biogel particles are then washed with pure water and placed in an anaerobic reactor. Samples are taken regularly to monitor the operation. The hydrogel beads are soaked in the Na2SO4 mixed solution for approximately 5 hours for curing.

[0061] Example 2

[0062] (1) Solution preparation: First, prepare an aqueous solution containing 9% polyvinyl alcohol (PVA) and 1% sodium alginate (SA), place it in an autoclave and autoclave at 121°C for 60 minutes, cool to room temperature, and mix them at a volume ratio of 1:1 to obtain a PVA-SA mixed solution; then prepare a solution containing 2% CaCl2 and 3% H3BO 3， A 0.1% aqueous solution of chitosan (CS) was prepared, and HCl was added dropwise to adjust the pH of the solution to 5. The mixture was then dissolved by ultrasonication to obtain a CaCl2-H3BO3-CS mixed solution.

[0063] (2) Preparation of biomass solution: The methanogenic sludge containing anaerobic sludge was washed at least 3 times in influent with carbon source removed, and then centrifuged at 7000 rpm for 2 min. The centrifuged anaerobic activated sludge was added to the PVA-SA mixed solution at a ratio of 3 g / L, and 1 g / L of carbon black was added. The mixture was stirred evenly to obtain the biomass solution.

[0064] (3) Preparation of biogel: Draw up the biomass solution described in step (2) with a syringe, and then drip it evenly into the CaCl2-H3BO3-CS mixed solution described in step (1) using a specially made syringe needle with a diameter of about 3 mm. After the gel is prepared, it should be continuously reinforced in the CaCl2-H3BO3-CS mixed solution for 1 hour.

[0065] (4) Gel curing: The hydrogel particles are soaked in a Na2SO4 mixed solution for curing. The biogel particles are finally washed with pure water and placed in an anaerobic reactor. Samples are taken regularly to monitor the operation.

[0066] Comparative Example 1

[0067] The hydrogel was prepared according to Example 1, except that the hydrogel prepared in step (1) was an aqueous solution containing 6% polyvinyl alcohol and 1% sodium alginate.

[0068] The above configuration results show that significant leakage occurred on the third day, the gel structure was damaged, and the gel spheres were too soft. Figure 12 ).

[0069] Comparative Example 2

[0070] The hydrogel was prepared according to Example 1, except that the preparation in step (1) was an aqueous solution containing 10% polyvinyl alcohol and 1% sodium alginate.

[0071] The above configuration results show that the gel sphere structure is too rigid, resulting in poor permeation experiment results, which is speculated to affect the mass transfer of the reaction.

[0072] Comparative Example 3

[0073] The hydrogel was prepared according to Example 1, except that in step (3), the gel was not continuously reinforced in the CaCl2-H3BO3-CS mixed solution for 1 hour after preparation. As a result, obvious adhesion occurred.

[0074] Comparative Example 4

[0075] The hydrogel was prepared according to Example 1, but the difference was that in step (3), the solution was not rotated while being injected at the edge of the liquid surface. As a result, obvious adhesion occurred.

[0076] Effect Example

[0077] A laboratory-scale batch reaction vessel for biogel particles was constructed. The effective volume of the reaction vessel was 200 mL. After placing the prepared biogel particles into the reaction vessel, artificially prepared water with 6.0 mg / L SMX (specific composition shown in Table 1, chemical oxygen demand (COD) 3000 mg / L) was added as the reactor feed water. Methane gas generated by the degradation of organic matter in wastewater by the biogel particles was collected periodically through a top gas tube. A control group was set up, in which anaerobic activated sludge was added, and the pollutant removal reaction was carried out in the same environment.

[0078] Water and gas samples were taken at regular intervals to determine the degradation of SMX, the removal of COD, and the formation of methane. The final results are as follows:

[0079] Table 2 is a schematic diagram showing the methanogenesis of the biogel particles of the present invention in the activity test. Figure 3 The cumulative yield curve and final yield bar chart for methane under a 25-day reaction cycle are shown. To quantitatively analyze methane yield under different conditions, this study applied a modified Gompertz model:

[0080]

[0081] Where P(t) is the cumulative methane production (m³ / L) at time t. -1 ); P max The maximum methane potential at the end of cultivation (mLL) -1 ); t is time (day); R max The maximum methane production rate (mLL) -1 day -1 )); λ is the lag period (day); e = 2.71828.

[0082] The fitting results of the Compertz model parameters for methane are shown in Table 2. Based on the modified Compertz model (fitting R0), 2 The values ​​were 0.993, 0.985, and 0.991, respectively, indicating the maximum methane yield (mLL) of the three experimental groups. -1 day-1 The lag period (days) were 28.99±0.50, 31.48±0.42, 24.54±0.11 and 6.50±0.20, 8.33±0.49, 11.48±0.54, respectively. It is evident that the maximum methane yield of the 7.5% PVA+1% SA gel group was superior to the other groups, and the maximum methane potential of the gel group at the end of the culture was superior to that of the sludge group.

[0083] Table 3 is a schematic diagram showing the COD removal performance of the biogel particles of the present invention as determined by the activity experiment. Figure 4 The degradation curves and bar charts of COD during a 25-day reaction cycle are shown; the influent COD concentration was set at 3 g / L. The COD concentration in all three reactors decreased over time. Under steady-state conditions, the COD removal rates for the three experimental groups were 67.74%, 51.79%, and 43.64%, respectively. The traditional method reached its maximum removal rate of 406.67 mg / L on the first day. -1 day -1 The gel group reached its maximum removal rate on days 15 and 13, respectively, at 608.33 mg / L. -1 day -1 ) and 601.67 (mg / L) -1 day -1 Therefore, the maximum COD removal rate of the gel group was superior to that of the control group, increasing by 49.59% and 47.95%, respectively.

[0084] Table 4 is a schematic diagram showing the removal of SMX in the biogel particles of the present invention as determined by the activity experiment. Figure 5 The graphs show the SMX degradation over a 25-day reaction period and the SMX removal rates of each group before and after the reaction. The influent SMX concentration was set at 6 mg / L. The SMX concentration in all three reactors decreased over time. From 0 to 13 days, the SMX removal was most significant (>60%) in all three reactors, and the effluent SMX concentration decrease was greater in the 7.5% PVA+1% SA gel group and the 9% PVA+1% SA gel group than in the sludge group (control group). The gel structure promoted SMX degradation. SMX degradation tended to stabilize in all three reactors after 13 days. Under stable conditions, the SMX removal rates of the sludge group (control group), the 7.5% PVA+1% SA gel group, and the 9% PVA+1% SA gel group were 67.74%, 90.23%, and 87.74%, respectively. Compared with the control group, the gel group showed a significantly higher SMX degradation efficiency.

[0085] Figure 6 , Figure 7 , Figure 8Cross-sectional SEM images of the 7.5% PVA+1% SA gel group and the 9% PVA+1% SA gel group before and after the reaction (25 days) are shown. After the reaction, a large number of aggregates were found in the cross-section of the gel beads. The pore size of the gel beads was approximately 300 μm before the reaction, and decreased to approximately 150 μm after 25 days of reaction. The microorganisms in the gel beads changed from the original surface-attached state to an embedded state and secreted a large amount of extracellular secretions, indicating that anaerobic microorganisms can accumulate and grow within the gel beads.

[0086] Figure 9 , Figure 10 The images show cross-sectional microscopic images of the 7.5% PVA+1% SA gel group and the 9% PVA+1% SA gel group, respectively. The black dots represent carbon black encapsulated in the cross-linked network structure.

[0087] Table 1. Content of various substances in artificially prepared water

[0088]

[0089] Table 2 Compertz Model Fitting Results Parameter Table

[0090]

[0091] Table 3 COD Degradation Status

[0092]

[0093] Table 4 SMX Degradation Status

[0094]

[0095] The above description, in conjunction with specific / preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a conductive bio-hydrogel, characterized in that: Includes the following steps: (1) Prepare an aqueous solution containing polyvinyl alcohol and sodium alginate, sterilize it, and mix it to obtain a PVA-SA mixed solution; (2) Prepare an aqueous solution containing CaCl2, H3BO3 and chitosan, adjust the pH of the solution to 5, and mix to obtain a CaCl2-H3BO3-CS mixed solution; (3) Add the anaerobic activated sludge containing hydrolytic acidifying bacteria, acetic acid-producing bacteria and methanogenic bacteria to the PVA-SA mixed solution prepared in step (1), add carbon black, mix and stir evenly to obtain a biomass solution. (4) Use a syringe to draw up the biomass solution prepared in step (3) and evenly drip it into the CaCl2-H3BO3-CS mixed solution in step (2). After the gel is prepared, it should be continuously reinforced in the CaCl2-H3BO3-CS mixed solution for 1 hour to obtain the conductive biohydrogel. In the PVA-SA mixed solution described in step (1), the concentration of polyvinyl alcohol is 7.5 wt% to 9 wt%; the concentration of sodium alginate is 1 wt%. In the CaCl2-H3BO3-CS mixed solution mentioned in step (2), the concentration of CaCl2 is 1 wt% to 3 wt%; the concentration of the H3BO3 aqueous solution is 2 wt% to 4 wt%; and the concentration of chitosan is 0.05 wt% to 0.2 wt%. The amount of anaerobic activated sludge added in step (3) is calculated based on its concentration in the system being 2 to 4 g / L; The amount of carbon black added in step (3) is calculated based on its concentration in the system being 0.5 to 2 g / L; While adding the solution in step (4), the CaCl2-H3BO3-CS mixed solution is rotated at a speed of 330-350 rpm.

2. The method for preparing the conductive bio-hydrogel according to claim 1, characterized in that: In the CaCl2-H3BO3-CS mixed solution mentioned in step (2), the concentration of CaCl2 is 2 wt%; the concentration of H3BO3 aqueous solution is 3 wt%; and the concentration of chitosan is 0.1 wt%.

3. The method for preparing the conductive bio-hydrogel according to claim 1, characterized in that: The sterilization mentioned in step (1) is high-pressure sterilization at 121℃ for 60±10 minutes in an autoclave; The pH adjustment of the solution in step (2) is achieved using HCl.

4. The method for preparing the conductive bio-hydrogel according to claim 1, characterized in that: The amount of anaerobic activated sludge added in step (3) is calculated based on its concentration in the system being 3 g / L; The amount of carbon black added in step (3) is calculated based on its concentration in the system being 1 g / L; The needle diameter of the syringe described in step (4) is 3 ± 0.5 mm; The dripping rate described in step (4) is 100 ± 10 drops / min.

5. A conductive bio-hydrogel, characterized in that: It is obtained by the preparation method described in any one of claims 1-4.

6. The application of the conductive biohydrogel as described in claim 5 in wastewater treatment.

7. The application according to claim 6, characterized in that: The wastewater in question contains COD and / or antibiotic drugs.

8. The application according to claim 7, characterized in that: The concentration of COD is not less than 3 g / L; The antibiotics mentioned include sulfamethoxazole; The concentration of sulfamethoxazole is not less than 6 mg / L.

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