Manganese-doped sludge-derived biochar material, preparation method and application

Abstract

The invention relates to a manganese-doped sludge-derived biochar material. The biochar material comprises a biochar matrix prepared by taking sludge as a raw material and manganese ions loaded on the biochar matrix. According to the manganese-doped sludge-derived biochar material disclosed by the invention, sludge is creatively taken as a raw material, a biochar matrix material is prepared by a pyrolysis method, the resource utilization of the sludge is well realized, the graphitization degree of a biochar matrix is remarkably improved, the porosity and chemical properties of the biochar matrix are changed and modified by adding a manganese element, and the manganese-doped sludge-derived biochar material is prepared. The prepared charcoal material finished product has high catalytic efficiency and a stable catalytic effect, and has a good application prospect in degradation treatment of antibiotics in a water body.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biochar materials, in particular to a manganese-doped sludge-derived biochar material, a preparation method and an application thereof. BACKGROUND

[0002] At present, sulfonamides, tetracyclines, quinolones and other antibiotics are widely used in medical treatment, livestock and aquaculture. Some antibiotics are discharged into water bodies in the form of original drugs or metabolites, resulting in a large increase in antibiotic residues in the natural environment. At present, antibiotics have been detected in surface water, groundwater, seawater, drinking water and municipal sewage, posing a potential risk to human health. In the prior art, conventional water treatment processes such as biodegradation, adsorption, chlorination have low antibiotic removal efficiency and are prone to produce toxic by-products. However, how to develop an economical and efficient catalyst to activate peroxide to degrade pollutants is a difficult and important problem.

[0003] At the same time, the global sludge production exceeds 100 million tons per year. The traditional landfill / incineration method faces problems such as land occupation, greenhouse gas emission and heavy metal pollution. Therefore, how to realize the resource utilization of sludge is also a problem to be solved.

[0004] The present application aims to develop a manganese-doped sludge-derived biochar material, a preparation method and an application thereof, so as to realize the resource utilization of sludge and efficiently, high-quality and low-cost treatment of water body antibiotics. SUMMARY

[0005] The present application aims to develop a manganese-doped sludge-derived biochar material, a preparation method and an application thereof, so as to realize the resource utilization of sludge and efficiently, high-quality and low-cost treatment of water body antibiotics.

[0006] The second technical problem solved by the present application is to provide a preparation method of the manganese-doped sludge-derived biochar material, so as to prepare an efficient and stable manganese-doped sludge-derived biochar material.

[0007] The third technical problem solved by the present application is to provide an application of the manganese-doped sludge-derived biochar material in water body antibiotic treatment.

[0008] The technical problems solved by the present application are solved by the following technical solutions: A manganese-doped sludge-derived biochar material, wherein the biochar material comprises a biochar matrix prepared from sludge and manganese ions loaded on the biochar matrix.

[0009] The preparation method of the manganese-doped sludge-derived biochar material comprises the following steps: S1, a first heat treatment is performed on sludge as raw material under the condition of inert gas to obtain a biochar matrix; S2, the biochar matrix is dispersed in a first dispersion liquid to obtain a first solution, phenanthroline and a manganese-containing compound are dispersed in a second dispersion liquid to obtain a second solution, the second solution is added to the first solution, and a second heat treatment is performed and then dried to obtain a manganese-containing biochar crude material; S3, the manganese-containing biochar crude material is subjected to a third heat treatment, and then subjected to acid washing, water washing and drying in sequence to obtain the biochar material.

[0010] Further, in step S1, the sludge raw material is dried sludge from the secondary sedimentation tank of a sewage treatment plant; in the first heat treatment, the temperature is raised to 700-900°C at a rate of 4-6°C / min, maintained for 1.5-2.5h, then lowered to 250-350°C at a rate of 8-9°C / min, and then naturally cooled down to obtain the biochar matrix. In this step, slow heating at a specific rate can protect the skeleton structure of the biochar matrix material and avoid the high internal pressure of biomass caused by a large amount of gas generated instantaneously due to rapid heating, thereby damaging the material structure. The high temperature of 700-900°C maintained for 1.5-2.5h is to ensure that the amorphous carbon and non-crystalline structure in the biochar have sufficient time to rearrange and grow into graphite microcrystals, and the heat preservation pyrolysis makes the reaction more complete and the pore structure more stable. Moreover, the ash in the biomass may melt or phase change under high temperature treatment to form a more stable form, thereby improving the overall catalytic performance of the material. The temperature lowering process is critical. If the temperature is lowered naturally in air, the temperature difference is too large and the cooling rate is too fast, which will cause thermal expansion and contraction unevenly and generate a lot of thermal stress, causing the carbon skeleton to crack, the micropores to collapse, and the graphite microcrystals to have defects.

[0011] Further, in step S3, the second heat treatment includes water bath heating at 60-80°C for 10-14h, and then drying at 50-70°C.

[0012] Further, in step S2, the volume ratio of the second solution to the first solution is 0.5-1.0:50.

[0013] Further, in step S2, the ratio of the mass of the biochar matrix to the volume of the first dispersion solution is 0.4-0.6 g:40-60 ml; the mass-volume ratio of the o-phenanthroline, the manganese-containing compound, and the second dispersion solution is 200-250 mg:30-40 mg:1.5-2.5 ml; the first dispersion solution and the second dispersion solution are both ethanol solutions, and preferably, the ethanol solution is an ethanol solution with a mass fraction of 98%. The manganese-containing compound includes one or more of manganese acetylacetonate, manganese dioxide, or potassium permanganate. Further, the o-phenanthroline can be replaced by 2,2'-dipyridyl.

[0014] Further, in step S3, the third heat treatment is performed at a rate of 4-6 ℃ / min to 500-700 ℃, and maintained for 1-3 h; then the material is pickled with 0.4-0.6 M sulfuric acid at 50-70 ℃ for 20-30 h, and then washed with water until neutral. In this step, pickling is very important, and the pickling process is used to remove inorganic ash in the manganese-containing biochar crude material, thereby significantly improving the pore structure and specific surface area of the manganese-containing biochar crude material. At the same time, some toxic heavy metals that may exist in the preparation of the manganese-containing biochar crude material can be leached out by pickling, thereby improving the environmental safety of the biochar and avoiding secondary release of the biochar to pollute the environment. In the preparation process, the prepared material is subjected to sufficient pickling, thereby improving the degradation performance of the material. In this process, the pickling conditions are relatively critical, and if the pickling time is not enough, the material cannot be completely treated, and if the pickling time is too long, the structure of the material will be damaged. In the present application, the reaction rate can be effectively improved within the given range, but if the temperature is too high, the material will be damaged, causing a series of adverse effects such as pore collapse, decrease in specific surface area, and decrease in mechanical strength.

[0015] The application of the manganese-doped sludge-derived biochar material in water body antibiotic treatment, characterized in that it comprises the following steps: The manganese-doped sludge-derived biochar material is mixed with the water body containing antibiotics to obtain a mixed solution; The peroxysulfate is added to the mixed solution to perform a catalytic oxidation reaction; Further, the water body containing antibiotics contains sulfonamidomethylpyrimidine, and the initial concentration of the sulfonamidomethylpyrimidine in the wastewater is 40-60 mg / L; the addition amount of the manganese-doped sludge-derived biochar material is 0.05-0.1 g / L; and the concentration of the peroxysulfate in the mixed solution after the addition of the peroxysulfate is 0.01-2.5 mM.

[0016] Beneficial effects: The manganese-doped sludge-derived biochar material of the application creatively uses sludge as raw material to produce biochar material by pyrolysis, which realizes the resource utilization of sludge, and the biochar prepared from sludge has a larger specific surface area and a higher porosity, can better disperse manganese metal particles, prevent manganese metal particles from agglomeration, the rich surface functional groups can produce an interaction force between manganese metal particles and biochar to prevent manganese metal from desorption, and promote the catalytic process, in addition, the inherent metal element composition in the biochar matrix prepared from sludge and the externally added manganese element can form metal-graphite carbon and metal-heterogeneous element-carbon interface in the processing process, the addition of manganese element can significantly improve the graphitization degree of the biochar matrix, change and modify the porosity and chemical properties, so that the prepared biochar material product has high catalytic efficiency and stable catalytic effect.

[0017] The preparation method of the manganese-doped sludge-derived biochar material of the application, the sludge-derived biochar material prepared by the method of the application has a higher specific surface area and pore volume than ordinary biochar material, and the pore structure of the biochar can be further changed by the modification of manganese element, the adsorption sites and activation sites are increased, and the catalytic efficiency of the material is improved. The method of the application has the characteristics of green environmental protection, simple process, easy to control nodes, and strong operability, and the integrated biochar material has the advantages of low processing cost, high processing efficiency and good processing effect in water body treatment.

[0018] The application of the manganese-doped sludge-derived biochar material in water body antibiotic degradation, by preparing a biochar matrix from sludge and creatively modifying only an appropriate amount of manganese element, the degradation efficiency of SMX within 10 minutes is higher than 90%, and the highest is 96%, which reduces the cost while improving the catalytic efficiency and catalytic effect of the catalyst. The application provides a green and efficient solution for water body antibiotic removal, and has good practical promotion and application value. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The figure is the degradation efficiency of SMX of the sludge-derived biochar material with different Mn doping amounts in Example 1 of the application (wherein a is the degradation efficiency of SMX of the Mn-doped sludge-derived biochar material with different concentrations of PMS activation, and b is the 1 / C t -1 / C0 with the change of reaction time).

[0020] Figure 2The image shows a transmission electron microscope (TEM) image of the biochar material in Example 1 of this invention. (where a is the TEM image of the product corresponding to BC, b is the TEM image of the product corresponding to Mn-BC-2, c is the product corresponding to Mn-BC-2, and d is the EDS elemental mapping (O, K, Mn, and Mg) of the product corresponding to Mn-BC-2.

[0021] Figure 3 The images show the XRD patterns of sludge-derived biochar materials with different manganese doping levels in Example 1 of this invention.

[0022] Figure 4 These are the Raman and FTIR spectra from Embodiment 1 of the present invention. (a is the Raman spectrum, b is the FTIR spectrum).

[0023] Figure 5 This is a graph showing the effect of different PMS dosages on SMX removal rate in Example 2 of the present invention.

[0024] Figure 6 This is a graph showing the effect of different amounts of Mn-doped sludge-derived biochar materials on SMX removal efficiency in Example 3 of the present invention.

[0025] Figure 7 In Example 4 of this invention, the effect of different pH environments on the catalytic degradation efficiency of Mn-doped sludge-derived biochar materials is shown (a represents the effect of different pH environments on SMX degradation efficiency, b represents 1 / C). t (Graph showing the change of -1 / C0 with reaction time).

[0026] Figure 8 This is a graph showing the effect of different types and amounts of quenchers on the catalytic degradation efficiency of the present invention in Example 4 of the present invention (where a is the effect of different quencher types on SMX degradation, b is the effect of different MeOH concentrations on SMX degradation, c is the effect of different TBA concentrations on SMX degradation, and d is the effect of different FFA concentrations on SMX degradation). Detailed Implementation

[0027] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments.

[0028] Example 1 The manganese-doped sludge-derived biochar material described in this embodiment includes a biochar matrix prepared from sludge and manganese ions loaded on the biochar matrix.

[0029] The preparation method of manganese-doped sludge-derived biochar materials includes the following steps: S1. Using sludge from the secondary sedimentation tank of a wastewater treatment plant as raw material, after drying, the biochar matrix is ​​obtained by first heat treatment under the condition of passing inert gas. During the first heat treatment, the temperature is raised to 800℃ at a rate of 5℃ / min, held for 2 hours, then cooled to 300℃ within 60 minutes, and then cooled naturally to obtain the biochar matrix.

[0030] S2. 0.5 g of biochar matrix was dispersed in 50 ml of 98% ethanol solution to obtain the first solution. 220 g of o-phenanthroline and 35 mg of manganese acetylacetone were ultrasonically dispersed in 2 ml of 98% ethanol solution to obtain the second solution. 0.5 ml, 0.7 ml, 1 ml, and 0 ml of the second solution (corresponding to the final products Mn-BC-1, Mn-BC-2, Mn-BC-3, and BC, respectively) were added to the first solution. After ultrasonic treatment for 30 min, a second heat treatment was performed. The second heat treatment was as follows: stirring in a 70°C water bath for 12 h, evaporating to dryness, and then drying in a 60°C oven for 12 h. The resulting manganese-containing biochar coarse material was then ground and collected. S3. The manganese-containing biochar crude material is subjected to a third heat treatment. The third heat treatment is as follows: the manganese-containing biochar crude material is placed in a ceramic boat and heated to 600°C at a heating rate of 5°C / min, and held for 2 hours. Then, the resulting material is acid-washed with 0.5M sulfuric acid in a 60°C water environment for 24 hours, then washed with water until neutral, and dried to obtain the biochar material.

[0031] (a) The catalytic degradation efficiency of SMX by PMS of the products corresponding to Mn-BC-1, Mn-BC-2, Mn-BC-3, and BC was statistically analyzed, and the results are as follows: Figure 1 As shown in the figure. The results indicate that compared with biochar materials without any Mn doping, biochar materials with added manganese exhibit significantly improved catalytic efficiency. The degradation efficiency of biochar materials without any Mn doping is only about 84% after 10 minutes, and its reaction rate constant k... app =1.38×10 -4 min -1 (All reaction rate constants mentioned in this article are second-order reaction rate constants.) In this invention, the degradation efficiency of biochar materials doped with Mn is significantly improved within 10 minutes. For example, the product corresponding to Mn-BC-2 can achieve an efficiency of approximately 93% in catalyzing the degradation of SMX by PMS within 10 minutes, and its reaction rate constant k... app It is 6.77×10 -4 min -1 .

[0032] Furthermore, compared to Mn-BC-2 and Mn-BC-3, its reaction rate constant k app The values ​​are 6.77 × 10⁻⁶. -4 min-1 6.08×10 -4 min -1 This indicates that once the manganese content reaches a certain level, further increasing the manganese content actually decreases the reaction rate. The speculated reason is that appropriate Mn doping can preserve the porous structure of BC, providing more adsorption sites, but excessive doping will damage the pores, thus reducing the contact area between the antibiotic and the active sites.

[0033] (II) The internal structure of the corresponding products of Mn-BC-2 and BC was analyzed using transmission electron microscopy (TEM). The results are as follows: Figure 2 As shown. From Figure 2 Figures a and b show that the biochar matrix prepared from sludge has a rich pore structure (white spots). Figures b and c show that the pore structure is even richer after doping with Mn. As shown in Figure d, O, K, Mn, and Mg are uniformly dispersed on the catalyst surface, with a high degree of overlap between the positions of Mn and O, which may lead to the formation of Mn oxides.

[0034] Therefore, it can be seen that the biochar matrix prepared by sludge in this invention has a large specific surface area and rich pore structure due to manganese doping, and the successful doping of Mn promotes the formation of metal active sites in Mn-BC materials.

[0035] (III) XRD technology was used to analyze the products corresponding to Mn-BC-1, Mn-BC-2, Mn-BC-3, and BC. The results are as follows: Figure 3 As shown.

[0036] The results showed that in the XRD patterns of the Mn-BC products, two typical peaks centered at 21.0° and 50.5° corresponded to the (002) and (004) crystal planes of the carbon material after pyrolysis, respectively, while the peaks at 26.8° and 68.4° should correspond to the (011) and (400) crystal planes of SiO2 carried by the sludge itself during the material preparation process. In the Mn-BC-1, Mn-BC-2, and Mn-BC-3 products, the peaks at 21.0°, 26.8°, 50.5°, and 68.4° became high and sharp, indicating that the materials doped with manganese have higher crystallinity, larger grains, and more defects compared to the biochar matrix materials alone. Furthermore, it was shown that after Mn was doped into the biochar matrix, new characteristic peaks were formed at 36.7°, 39.7°, 42.7°, 46°, and 55.1°, with the 36.7° peak being a characteristic peak of Mn3O4 (PDF#18–0803), indicating that Mn was successfully doped into the biochar matrix material and formed a metal oxide.

[0037] (iv) Spectroscopic analysis was performed on the products corresponding to Mn-BC-1, Mn-BC-2, Mn-BC-3, and BC to compare the differences between sludge-derived biochar materials with different Mn doping amounts and the original BC materials. The structures are as follows: Figure 4 As shown.

[0038] As shown in the Raman spectra, the products corresponding to Mn-BC-1, Mn-BC-2, Mn-BC-3, and BC have values ​​at 1356 and 1591 cm⁻¹, respectively. -1 Similar peaks are observed at these locations, representing disordered carbon (D band) and graphitized carbon (G band), respectively. The ratio of the relative intensities of peak D and peak G (Ig) is... D / I G The values ​​were 2.57, 2.52, 2.47, and 2.45, respectively. As the amount of doped metal Mn increased, I... D / I G The increasing ratio indicates that the carbon atom metal has more defects after being doped with metal Mn. These defects can serve as electron-rich regions, enhancing the activation performance of persulfate.

[0039] Fourier transform infrared spectroscopy analysis, as shown in the FTIR spectra, revealed no significant differences in functional group properties between Mn-BC-1, Mn-BC-2, Mn-BC-3, and their BC counterparts. However, at 3748.8 cm⁻¹... -1 This corresponds to the stretching vibration of free OH groups, 3426.3 cm. -1 The peak represents the stretching vibration of the OH groups on the material, indicating that hydrogen-bonded hydroxyl groups corresponding to Mn-BC-1, Mn-BC-2, Mn-BC-3, and Mn-BC all enhance hydrophilicity and adsorption capacity. (2923.9 cm⁻¹) -1 and 2855.0cm -1 The stretching vibration of aliphatic CH at this point indicates that aliphatic chains or alkyl structures exist in the materials corresponding to Mn-BC-1, Mn-BC-2, Mn-BC-3, and Mn-BC, possibly originating from residual organic components after the pyrolysis of biomass raw materials in the sludge. 1618.1 cm -1 The 10804 cm⁻¹ is due to the in-plane bending vibration of the NH group in the amide. -1 The peak corresponding to the symmetric stretching vibration of Si-O-Si indicates that Mn-BC-1, Mn-BC-2, Mn-BC-3, and Mn-BC materials contain silicon impurities or silicon-based modifications. However, the Mn-BC-1, Mn-BC-2, Mn-BC-3, and Mn-BC catalysts exhibit stronger functional group peak intensities compared to the original Mn-BC catalyst, and the higher the Mn doping concentration, the stronger the peak intensity. Therefore, Mn-doped sludge-derived biochar materials improve the properties of their original materials.

[0040] Example 2 Four groups of 5 mg Mn-BC-2 material (the biochar material product obtained in Example 1) were placed in 150 mL beakers respectively. 25 mL of ultrapure water was measured using a graduated cylinder and added to each beaker. After ultrasonic dispersion, the beakers were placed in a magnetic rotor on a magnetic stirrer. 25 mL of SMX (sulfadimethylpyrimidine) was added to initiate the reaction. After 30 min of adsorption, samples were taken. Then, 0 mM, 1 mM, 2 mM, and 3 mM PMS (persulfate) were added respectively, and samples were taken at 1 min, 2 min, 3 min, 5 min, 7 min, and 10 min. For each sample, 0.5 mL of the reaction sample was added to 1 mL of methanol (quencher), mixed well, filtered through a 0.45 μm filter into a liquid chromatography bottle, and subsequently analyzed using high-performance liquid chromatography (HPLC).

[0041] Test results as follows Figure 5 As shown, the results indicate that when the PMS dosage increased from 0 mM to 2 mM, the degradation efficiency of SMX increased from approximately 67% to approximately 95% within 10 minutes. This is presumably because the number of activated free radicals increases with increasing PMS dosage, thus enhancing the degradation ability of SMX. However, when the PMS concentration reached 2 mM and was further increased to 3 mM, the degradation efficiency of SMX decreased from 95% to 90% within 10 minutes. This is presumably because the SO4•- generated by activated PMS has strong oxidizing properties, which may react with the active substances in the Mn-BC / PMS system, thereby reducing the degradation efficiency of SMX.

[0042] Example 3 Weigh 0, 2, 5, 7, and 10 mg of Mn-BC-2 material (the biochar material product obtained in Example 1) into 150 mL beakers, respectively. Add 25 mL of ultrapure water using a graduated cylinder, sonicate, and place the beakers on a magnetic stirrer. Then add 25 mL of SMX to initiate the reaction. After adsorption for 30 min, take samples. Then add 2 mM potassium peroxymonosulfate to each sample and take samples at 1 min, 2 min, 3 min, 5 min, 7 min, and 10 min. For each sample, add 0.5 mL of the reaction sample to 1 mL of methanol, mix well, and filter through a 0.45 μm filter into a liquid chromatography bottle. Detect the sample using a high-performance liquid chromatograph (HPLC).

[0043] The results are as follows Figure 6As shown, the results indicate that when the concentration of Mn-BC-2 material in SMX-containing water increased from 0.04 g / L to 0.1 g / L, the degradation efficiency of SMX increased from approximately 80% to approximately 95%, indicating that the activation ability of the catalyst gradually increases with the increase of the amount of catalyst. However, when the amount of catalyst reaches a certain level, the catalyst efficiency remains almost unchanged. For example, the degradation efficiency within 10 minutes is almost the same when the concentration of Mn-BC-2 material in SMX-containing water is 0.1 g / L, 0.14 g / L, and 0.2 g / L. It is speculated that the reason is that within a certain range, the more catalyst is used, the more activation sites are provided, thus enabling more efficient catalysis of PMS to generate active free radicals, thereby improving the degradation efficiency. However, when the amount of catalyst reaches a certain level, the active sites provided for activating PMS become saturated, so the degradation efficiency is no longer affected by the amount of catalyst.

[0044] Example 4 Five groups of 5 mg Mn-BC-2 material (the biochar material product obtained in Example 1) were weighed and placed in 150 mL beakers respectively. 25 mL of ultrapure water was measured with a graduated cylinder and poured into each beaker. After ultrasonic dispersion, the beakers were placed in magnetic rotors and then on magnetic stirrers for reaction. 25 mL of SMX was added to adjust the pH to 2, 4, 6, 8 and 10 respectively. After stirring at room temperature for 30 min, samples were taken. Then 2 mL of LPMS was added to each sample, and samples were taken at 1 min, 2 min, 3 min, 5 min, 7 min and 10 min respectively. For each sample, 0.5 mL of the reaction sample was added to 1 mL of methanol (quencher), mixed well and filtered through a 0.45 μm filter into a liquid chromatography bottle, and then detected by high performance liquid chromatography.

[0045] The results are as follows Figure 7 As shown, the results indicate that the degradation rate of SMX by Mn-BC-2 is not significantly different under different pH conditions, and the degradation efficiency of SMX is greater than 90% within 10 min. However, the apparent rate constant generally decreases with increasing pH. When the pH value is 10, the apparent rate constant k... app The lowest is only 4.07×10 -4 min -1 The likely reason is that the alkaline environment causes the Mn-BC surface to carry a negative charge, thereby inhibiting the adsorption of PMS on the Mn-BC surface, reducing the activation efficiency of PMS, and thus reducing the degradation efficiency of SMX. However, overall, pH has little effect on the efficiency of Mn-BC in catalytic degradation of SMX, indicating that this material has good adaptability to water bodies with different acidity and alkalinity.

[0046] Example 5 This embodiment further investigates the main mechanism of SMX degradation by the biochar material described in this invention.

[0047] In this embodiment, excess MeOH, TBA, FFA, and p-BQ quenchers were added to the Mn-BC-2 system during the reaction process to conduct active substance capture experiments, thereby studying the main active species in the Mn-BC / PMS system. MeOH, TBA, FFA, and p-BQ were used as •OH / SO4 quenchers. •- •OH 1 O2, O2 •- Quenching agents for active species. Results are as follows: Figure 8 As shown.

[0048] from Figure 8 As shown in Figure a, the inhibitory effects of the four quenchers on SMX degradation were in the order of p-BQ > FFA > TBA > MeOH. This indicates that different quenchers inhibited the SMX degradation process in the Mn-BC / PMS system to varying degrees. p-BQ exhibited the strongest inhibitory effect, achieving approximately 80% inhibition of SMX degradation within 10 minutes. FFA showed an inhibition effect of approximately 25%, while TBA and MeOH had significantly weaker inhibitory effects, almost having no effect. This suggests that O2 plays a dominant role in the SMX degradation process in the Mn-BC / PMS system. •- , 1 O2 also played a certain role, as did •OH and SO4. •- It has almost no effect on the degradation of SMX.

[0049] like Figure 8 As shown in points b and c, the degradation efficiency of SMX remained almost unchanged within 10 minutes with increasing TBA and MeOH concentrations, further confirming the effects of •OH and SO4. •- It has almost no effect on the degradation of SMX.

[0050] like Figure 8 As shown in Figure d, increasing the concentration of FFA significantly increases the inhibitory effect. When the FFA concentration increases from 5 mM to 30 mM, the degradation efficiency of PMS decreases from approximately 90% to approximately 60%. Therefore, in the Mn-BC / PMS system, the degradation of SMX significantly affects the degradation of •OH and SO42-. •- The dependence is small or even non-existent; the main dependence is on and 1 O2 and O2 •- O2 •- It plays the most important role in the system.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A manganese-doped sludge-derived biochar material, characterized in that, The biochar material includes a biochar matrix prepared from sludge and manganese ions loaded on the biochar matrix.

2. The method for preparing manganese-doped sludge-derived biochar material according to claim 1, characterized in that, Includes the following steps: S1. Using sludge as raw material, biochar matrix is ​​obtained by first heat treatment under the condition of passing inert gas; S2. The biochar matrix is ​​dispersed in a first dispersion to obtain a first solution, and o-phenanthroline and manganese-containing compounds are dispersed in a second dispersion to obtain a second solution. The second solution is added to the first solution and subjected to a second heat treatment, followed by drying to obtain manganese-containing biochar crude material. S3. The manganese-containing biochar crude material is subjected to a third heat treatment, and then successively subjected to acid washing, water washing and drying to obtain the biochar material.

3. The method for preparing manganese-doped sludge-derived biochar material according to claim 2, characterized in that, In step S1, the sludge raw material is dried sludge from the secondary sedimentation tank of a sewage treatment plant; during the first heat treatment, the temperature is raised to 700-900℃ at a rate of 4-6℃ / min and held for 1.5-2.5h, then cooled to 250-350℃ at a rate of 8-9℃ / min, and then allowed to cool naturally to obtain the biochar matrix.

4. The method for preparing manganese-doped sludge-derived biochar material according to claim 2, characterized in that, In step S3, the second heat treatment includes: heating in a water bath at 60-80°C for 10-14 hours, and then drying at 50-70°C.

5. The method for preparing manganese-doped sludge-derived biochar material according to claim 2, characterized in that, In step S2, the volume ratio of the second solution to the first solution is 0.5~1.0:

50.

6. The method for preparing manganese-doped sludge-derived biochar material according to claim 2, characterized in that, In step S2, the mass ratio of the biochar matrix to the volume of the first dispersion is 0.4~0.6g:40~60ml; the mass-to-volume ratio of the o-phenanthroline, the manganese-containing compound, and the second dispersion is 200~250mg:30~40mg:1.5~2.5ml; both the first and second dispersions are ethanol solutions, and the manganese-containing compound includes one or more of manganese acetylacetonate, manganese dioxide, or potassium permanganate.

7. The method for preparing manganese-doped sludge-derived biochar material according to claim 2, characterized in that, In step S3, during the third heat treatment, the temperature is increased to 500-700℃ at a rate of 4-6℃ / min and held for 1-3 hours; then, the mixture is acid-washed with 0.4-0.6M sulfuric acid at 50-70℃ for 20-30 hours, and then washed with water until neutral.

8. The application of a manganese-doped sludge-derived biochar material as described in any one of claims 1 to 7 in the treatment of antibiotics in water bodies, characterized in that, Includes the following steps: Manganese-doped sludge-derived biochar material was mixed with antibiotic-containing water to obtain a mixed solution; Simply add persulfate to the mixture to initiate a catalytic oxidation reaction.

9. The application according to claim 8, characterized in that, The amount of manganese-doped sludge-derived biochar material added is 0.05~0.1 g / L; the concentration of persulfate in the mixture after the addition of persulfate is 0.01~2.5 mM.

10. The application according to claim 8, characterized in that, The aforementioned wastewater containing antibiotics contains sulfadiazine, with an initial concentration of sulfadiazine of 40-60 mg / L.

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