Iron modified biochar as well as preparation method and application thereof

Abstract

The invention discloses iron modified biochar as well as a preparation method and application thereof, and relates to the technical field of water treatment. The invention specifically discloses a preparation method of iron modified biochar, which comprises the following steps: preparing a first mixture containing an iron ion solution and biochar, reacting, and drying to obtain a solid phase; under the atmosphere of nitrogen and / or inert gas, the solid phase is subjected to heat treatment, and the iron modified biochar is obtained. The prepared iron modified biochar can effectively degrade sulfonamide antibiotics such as sulfamethoxazole, promote cascade degradation of fatty acid, produce methane and promote removal of drug-resistant genes such as sul1, sul2 and intI1.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to an iron-modified biochar and its preparation method and application. Background Art

[0002] Sulfonamide antibiotics (SAs) are a class of antibiotics widely used in clinical and aquaculture. The main pollutants in sulfonamide drug production wastewater are polysaccharide organic matters, with high residual amounts of SAs and their intermediate organic matters, and the chemical oxygen demand (COD) can reach tens of thousands of milligrams per liter, which is a typical refractory and high-concentration organic wastewater. The abuse of SAs and the discharge of substandard sulfonamide drug production wastewater are likely to cause water pollution, affecting human health and the stability of the ecosystem.

[0003] In related technologies, physical and chemical methods + anaerobic + aerobic biological treatment methods are mostly used to treat organic wastewater containing antibiotics. The physical and chemical methods + anaerobic + aerobic biological treatment methods generally use physical and chemical pretreatment (such as hydrothermal hydrolysis, microwave, ultrasound, etc.) to break the stable chemical structure (such as benzene ring) of SAs to improve the biodegradability of wastewater and reduce the biological inhibition effect, and then use anaerobic microorganisms and aerobic microorganisms to further synergistically degrade organic matters. However, there are phenomena such as SAs residues in physical and chemical treatment, resulting in problems such as the accumulation and insufficient stability of volatile fatty acids (VFAs) such as acetic acid, propionic acid, and butyric acid in the subsequent anaerobic treatment system. Related research shows that the presence of SAs will hinder the degradation of fatty acids such as acetic acid, propionic acid, and butyric acid, and the higher the concentration of SAs, the more obvious the fatty acid accumulation. Therefore, it is crucial to provide an effective strategy for efficiently removing SAs and fatty acids in water. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides an iron-modified biochar, which can effectively promote the degradation of sulfonamide antibiotics such as sulfamethoxazole and fatty acids.

[0005] The present invention also provides an iron-modified biochar.

[0006] The present invention also provides the application of the above iron-modified biochar.

[0007] The present invention also provides a treatment method for wastewater containing sulfonamide antibiotics.

[0008] According to a first aspect embodiment of the present invention, a preparation method of an iron-modified biochar includes the following steps: Prepare a first mixture including an iron ion solution and biochar, react, dry to obtain a solid phase; under a nitrogen and / or inert gas atmosphere, the solid phase is heat-treated to obtain the iron-modified biochar.

[0009] According to some embodiments of the present invention, the iron ion (Fe3+ The source of ) includes at least one of iron chloride, iron sulfate, iron nitrate, iron acetate, and iron(III) oxide.

[0010] According to some embodiments of the present invention, the particle size of the biochar is 20 μm - 30 μm. For example, it can be 20 μm, 21 μm, 22 μm, 23 μm, 24 μm, 25 μm, 26 μm, 27 μm, 28 μm, 29 μm, or 30 μm.

[0011] According to some embodiments of the present invention, the molar mass ratio of the iron ions to the biochar is (1.0 - 2.5) mmol : 1 g. For example, it can be 1 mmol : 1 g, 1.1 mmol : 1 g, 1.2 mmol : 1 g, 1.3 mmol : 1 g, 1.4 mmol : 1 g, 1.5 mmol : 1 g, 1.6 mmol : 1 g, 1.7 mmol : 1 g, 1.8 mmol : 1 g, 1.9 mmol : 1 g, 2 mmol : 1 g, 2.1 mmol : 1 g, 2.2 mmol : 1 g, 2.3 mmol : 1 g, 2.4 mmol : 1 g, or 2.5 mmol : 1 g.

[0012] According to some embodiments of the present invention, in the iron ion solution, the concentration of the iron ions is 35 mmol / L - 50 mmol / L. For example, it can be 35 mmol / L, 36 mmol / L, 37 mmol / L, 38 mmol / L, 39 mmol / L, 40 mmol / L, 41 mmol / L, 42 mmol / L, 43 mmol / L, 44 mmol / L, 45 mmol / L, 46 mmol / L, 47 mmol / L, 48 mmol / L, 49 mmol / L, or 50 mmol / L.

[0013] According to some embodiments of the present invention, the solvent of the iron ion solution is water.

[0014] According to some embodiments of the present invention, the temperature of the reaction is 20°C - 35°C. For example, it can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, or 35°C.

[0015] According to some embodiments of the present invention, the reaction time is 12 h - 48 h. For example, it can be 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 26 h, 28 h, 30 h, 32 h, 34 h, 36 h, 38 h, 40 h, 42 h, 44 h, 46 h or 48 h.

[0016] According to some embodiments of the present invention, the stirring speed of the reaction is 30 rpm - 60 rpm. For example, it can be 30 rpm, 32 rpm, 34 rpm, 36 rpm, 38 rpm, 40 rpm, 42 rpm, 44 rpm, 46 rpm, 48 rpm, 50 rpm, 52 rpm, 54 rpm, 56 rpm, 58 rpm or 60 rpm According to some embodiments of the present invention, the drying temperature is 60°C - 90°C. For example, it can be 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, 80°C, 82°C, 84°C, 86°C, 88°C or 90°C.

[0017] According to some embodiments of the present invention, the drying time is 48 h - 72 h. For example, it can be 48 h, 50 h, 52 h, 54 h, 56 h, 58 h, 60 h, 62 h, 64 h, 66 h, 68 h, 70 h or 72 h.

[0018] According to some embodiments of the present invention, the inert gas includes at least one of helium, neon, argon, krypton, xenon, and radon.

[0019] According to some embodiments of the present invention, the heating rate of the heat treatment is 5°C / min - 10°C / min. For example, it can be 5°C / min, 5.5°C / min, 6°C / min, 6.5°C / min, 7°C / min, 7.5°C / min, 8°C / min, 8.5°C / min, 9°C / min, 9.5°C / min or 10°C / min.

[0020] According to some embodiments of the present invention, the treatment temperature of the heat treatment is 500°C - 600°C. For example, it can be 500°C, 510°C, 520°C, 530°C, 540°C, 550°C, 560°C, 570°C, 580°C, 590°C or 600°C.

[0021] According to some embodiments of the present invention, the time of the heat treatment is 3 h - 6 h. For example, it can be 3 h, 3.2 h, 3.4 h, 3.6 h, 3.8 h, 4 h, 4.2 h, 4.4 h, 4.6 h, 4.8 h, 5 h, 5.2 h, 5.4 h, 5.6 h, 5.8 h or 6 h.

[0022] The iron-modified biochar according to the embodiments of the second aspect of the present invention is prepared by the preparation method described in the embodiments of the first aspect.

[0023] Treatment of the iron-modified biochar as described in the above-mentioned second aspect embodiment according to the embodiments of the third aspect of the present invention for wastewater containing sulfonamide antibiotics.

[0024] According to some embodiments of the present invention, when the iron-modified biochar is applied to the treatment of wastewater containing sulfonamide antibiotics, it has at least one of the effects of A1) to A6): A1) Promote the removal of sulfonamide antibiotics; A2) Promote the removal of resistance genes; A3) Promote the removal of volatile fatty acids; A4) Promote methane production; A5) At the phylum level, enrich Euryarchaeota, Thermotogota, Firmicutes; A6) At the genus level, enrich Methanobacterium ( Methanobacterium ) AUTHM 297, Geobacter ( Geobacter )

[0025] According to some embodiments of the present invention, the resistance genes include sulfonamide resistance genes.

[0026] According to some embodiments of the present invention, the sulfonamide resistance genes include sul1 , sul2 , intI1 at least one of them.

[0027] According to some embodiments of the present invention, the volatile fatty acids include at least one of acetic acid, propionic acid, butyric acid, and valeric acid.

[0028] According to some embodiments of the present invention, the sulfonamide antibiotics include at least one of sulfamethoxazole, sulfadiazine, sulfisoxazole, sulfamethazine, sulfamonomethoxine, sulfacetamide, sulfamerazine, sulfathiazole, and sulfapyridine.

[0029] According to some embodiments of the present invention, the iron-modified biochar is used to enhance the anaerobic microbial treatment of sulfonamide antibiotic-containing wastewater.

[0030] A method for treating sulfonamide antibiotic-containing wastewater according to an embodiment of the fourth aspect of the present invention includes the following steps: Prepare a second mixture containing the iron-modified biochar, anaerobic microorganisms, and sulfonamide antibiotic-containing wastewater described in the embodiment of the second aspect, and perform anaerobic treatment.

[0031] According to some embodiments of the present invention, the mass-volume ratio of the iron-modified biochar to the sulfonamide antibiotic-containing wastewater is 1 g:(30 - 100) mL. For example, it can be 1 g:30 mL, 1 g:35 mL, 1 g:40 mL, 1 g:45 mL, 1 g:50 mL, 1 g:55 mL, 1 g:60 mL, 1 g:65 mL, 1 g:70 mL, 1 g:75 mL, 1 g:80 mL, 1 g:85 mL, 1 g:90 mL, 1 g:95 mL, or 1 g:100 mL.

[0032] According to some embodiments of the present invention, the anaerobic microorganisms are derived from anaerobic granular sludge.

[0033] According to some embodiments of the present invention, the VSS of the anaerobic granular sludge is 17 g / L - 21 g / L. For example, it can be 17 g / L, 17.5 g / L, 18 g / L, 18.5 g / L, 19 g / L, 19.5 g / L, 20 g / L, 20.5 g / L, or 21 g / L.

[0034] According to some embodiments of the present invention, the VSS / TSS of the anaerobic granular sludge is 0.4 - 0.9. For example, it can be 0.4, 0.42, 0.44, 0.46, 0.48, 0.5, 0.52, 0.54, 0.56, 0.58, 0.6, 0.62, 0.64, 0.66, 0.68, 0.7, 0.72, 0.74, 0.76, 0.78, 0.8, 0.82, 0.84, 0.86, 0.88, or 0.9.

[0035] According to some embodiments of the present invention, the volume ratio of the anaerobic granular sludge to the sulfonamide antibiotic-containing wastewater is (0.1 - 1):1. For example, it can be 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, or 1:1.

[0036] According to some embodiments of the present invention, the pH of the sulfonamide antibiotic-containing wastewater is 6.50 - 7.50. For example, it can be 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, or 7.5.

[0037] According to some embodiments of the present invention, the COD of the sulfonamide antibiotic-containing wastewater is 100 mg / L - 2000 mg / L. For example, it can be 100 mg / L, 200 mg / L, 300 mg / L, 400 mg / L, 500 mg / L, 600 mg / L, 700 mg / L, 800 mg / L, 900 mg / L, 1000 mg / L, 1100 mg / L, 1200 mg / L, 1300 mg / L, 1400 mg / L, 1500 mg / L, 1600 mg / L, 1700 mg / L, 1800 mg / L, 1900 mg / L, or 2000 mg / L.

[0038] According to some embodiments of the present invention, the mass ratio of C:N:P in the sulfonamide antibiotic-containing wastewater is (300 - 500):(3 - 5):1. For example, it can be 500:5:1.

[0039] According to some embodiments of the present invention, the concentration of sulfonamide antibiotics in the sulfonamide antibiotic-containing wastewater is 30 mg / L - 150 mg / L. For example, it can be 30 mg / L, 35 mg / L, 40 mg / L, 45 mg / L, 50 mg / L, 55 mg / L, 60 mg / L, 65 mg / L, 70 mg / L, 75 mg / L, 80 mg / L, 85 mg / L, 90 mg / L, 95 mg / L, 100 mg / L, 105 mg / L, 110 mg / L, 115 mg / L, 120 mg / L, 125 mg / L, 130 mg / L, 135 mg / L, 140 mg / L, 145 mg / L, or 150 mg / L.

[0040] According to some embodiments of the present invention, the sulfonamide antibiotic-containing wastewater includes trace elements.

[0041] According to some embodiments of the present invention, the trace elements include at least one of copper element, boron element, nickel element, manganese element, zinc element, cobalt element, iron element, aluminum element, and molybdenum element.

[0042] According to some embodiments of the present invention, the sulfonamide antibiotic-containing wastewater includes: Copper element: 0.1 mg / L - 0.2 mg / L, boron element: 0.05 mg / L - 0.09 mg / L, nickel element: 0.5 mg / L - 0.8 mg / L, H2SO4: 5 mg / L - 8 mg / L, manganese element: 0.1 mg / L - 0.2 mg / L, zinc element: 0.2 mg / L - 0.5 mg / L, cobalt element: 0.2 mg / L - 0.5 mg / L, iron element: 5 mg / L - 10 mg / L, aluminum element: 0.1 mg / L - 0.3 mg / L, molybdenum element: 0.02 mg / L - 0.05 mg / L.

[0043] According to some embodiments of the present invention, the copper element is derived from at least one of copper sulfate, copper chloride, and copper oxide.

[0044] According to some embodiments of the present invention, the boron element is derived from at least one of boric acid and magnesium boride.

[0045] According to some embodiments of the present invention, the nickel element is derived from at least one of nickel sulfate, nickel chloride, and nickel oxide.

[0046] According to some embodiments of the present invention, the manganese element is derived from at least one of manganese sulfate, manganese chloride, and manganese oxide.

[0047] According to some embodiments of the present invention, the zinc element is derived from at least one of zinc chloride, zinc sulfate, and zinc oxide.

[0048] According to some embodiments of the present invention, the cobalt element is derived from at least one of cobalt sulfate, cobalt chloride, and cobalt oxalate.

[0049] According to some embodiments of the present invention, the iron element is derived from at least one of ferrous dichloride, ferrous sulfate, and ferrous chloride.

[0050] According to some embodiments of the present invention, the aluminum element is derived from at least one of aluminum chloride and aluminum sulfate.

[0051] According to some embodiments of the present invention, the molybdenum element is derived from at least one of ammonium molybdate and sodium molybdate.

[0052] According to some embodiments of the present invention, the anaerobic microorganism is derived from anaerobic granular sludge.

[0053] According to some embodiments of the present invention, the temperature of the anaerobic treatment is 34°C - 37°C. For example, it can be 34°C, 34.5°C, 35°C, 35.5°C, 36°C, 36.5°C, or 37°C.

[0054] According to some embodiments of the present invention, the time of the anaerobic treatment is not less than 24 h.

[0055] According to some embodiments of the present invention, the time of the anaerobic treatment is 1 - 60 days. For example, it can be 1 day, 5 days, 10 days, 15 days, 20 days, 25 days, 30 days, 35 days, 40 days, 45 days, 50 days, 55 days or 60 days.

[0056] According to some embodiments of the present invention, the container for carrying out the anaerobic treatment includes at least one of an anaerobic baffled reactor (ABR), a sequencing batch reactor, and an upflow anaerobic sludge blanket reactor (UASB).

[0057] The present invention has at least the following beneficial effects: The preparation method of the embodiment is simple, with low cost, does not require the use of organic solvents, and has good environmental friendliness.

[0058] The iron-modified biochar of the embodiment can effectively degrade sulfonamide antibiotics such as sulfamethoxazole, and promote sul1 , sul2 , intI1 , etc. of the degradation of resistance genes. And by enriching electroactive microorganisms dominated by extracellular respiratory bacteria (ERB) and hydrogenotrophic methanogens (HM) suitable for living in an environment containing sulfonamide antibiotics, it can effectively promote the degradation of fatty acids such as acetic acid, propionic acid, butyric acid, and valeric acid, thereby promoting the cascade degradation of fatty acids and methane production, and solving the problem of fatty acid accumulation caused by antibiotic inhibition in the traditional anaerobic system.

[0059] Other features and advantages of the present invention will be described in the subsequent specification, and part of them will become obvious from the specification or be understood by implementing the present invention. Description of the Drawings

[0060] Figure 1 Characterization results of the iron-modified biochar prepared in Example 1; a) X-ray diffraction pattern, b) scanning electron microscope photograph; Figure 2 Schematic diagram of the grouping of 5 experimental groups in Test Example 1; among them, the black spheres represent anaerobic granular sludge, the green spheres represent biochar powder, the purple spheres represent zero-valent iron, and the red spheres represent the iron-modified biochar prepared in Example 1; Figure 3 Variation curve of SMX with time for each group in Test Example 1; Figure 4 For each group after running for 60 days in Test Example 1 Intl1 Quantity statistical results; Figure 5 For each group after running for 60 days in Test Example 1 Sul1 Quantity statistical results; Figure 6 For each group after running for 60 days in Test Example 1Sul2 Quantitative statistical results; Figure 7 Statistical results of the volatile fatty acid composition of each group after 60 days of operation in Test Example 1; Figure 8 Variation curve of chemical oxygen demand of each group over time in Test Example 1; Figure 9 Variation curve of pH of each group over time in Test Example 1; Figure 10 Statistical results of methane production rate of each group after 60 days of operation in Test Example 1; Figure 11 Differences in microorganisms at the phylum level of each group after 60 days of operation in Test Example 1; Figure 12 Differences in microorganisms at the genus level of each group after 60 days of operation in Test Example 1; Figure 13 Structural schematic diagram of an anaerobic baffled reactor; Figure 14 Variation curve of SMX concentration over time in Test Example 2; Figure 15 Variation curve of chemical oxygen demand concentration over time in Test Example 2; Figure 16 At the end of different stages in Test Example 2 intI1 Degradation situation; Figure 17 At the end of different stages in Test Example 2 sul1 Degradation situation; Figure 18 At the end of different stages in Test Example 2 sul2 Degradation situation. Detailed implementation manners

[0061] The concept of the present invention and the technical effects produced will be clearly and completely described below in conjunction with the embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0062] For those conditions not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0063] When a numerical range is disclosed herein, the above range is considered continuous and includes the minimum and maximum values of the range, as well as every value therebetween. Further, when the range refers to integers, every integer between the minimum and maximum values of the range is included. Additionally, when multiple ranges are provided to describe features or characteristics, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all sub-ranges subsumed therein.

[0064] "And / or" is used to indicate that one or both of the stated circumstances may occur, e.g., A and / or B includes (A and B) and (A or B).

[0065] The term "not less than" means greater than or equal to and should be understood to include the number itself.

[0066] Unless otherwise specified, "room temperature" in the present invention means (25 ± 5)°C.

[0067] The biochar powder was purchased from Sinopharm Chemical Reagent Co., Ltd., CAS: 7440 - 44 - 0, code: 10006619; the zero-valent iron was purchased from Sinopharm Chemical Reagent Co., Ltd., CAS: 7439 - 89 - 6, code: 10011816; the anaerobic granular sludge was cultivated in the laboratory reactor, black, and the sludge particle size of the anaerobic granular sludge was 3 mm - 7 mm.

[0068] Example 1 This example provides an iron-modified biochar, and its preparation method is as follows: Dissolve FeCl3·6H2O (1.5 mmol) in 40 mL of ultrapure water, and add 1.00 g of biochar powder under magnetic stirring. The temperature of the magnetic stirrer is set at 25°C, and the stirring duration is set at 24 h. After the reaction, put the reactants into an oven, the oven temperature is set at 80°C, and the drying duration is 72 h to obtain a powder. Place the powder in a tube furnace, continuously pass high-purity nitrogen in the tube furnace, the heating rate is 5°C / min, and keep it at 600°C for 4 h after the temperature reaches 600°C. Then cool it naturally to room temperature in the tube furnace to obtain the iron-modified biochar.

[0069] Characterize the prepared iron-modified biochar by an X-ray diffractometer and a scanning electron microscope. The results are as Figure 1 shown.

[0070] A sharp peak in the X-ray diffraction pattern is at 2θ = 45°. This indicates that nano zero-valent iron is loaded on the powdered biochar.

[0071] Detection Example 1 Using a sequencing batch experiment as a platform, with sulfamethoxazole (SMX) and glucose as substrates, adjusting the pH with NaHCO3, adding a nitrogen source (NH4Cl) and a phosphorus source (KH2PO4), with C:N:P = 500:5:1 (mass ratio). The COD of the substrate was 900 ± 30 mg / L, SMX was 95 ± 5 mg / L, and trace elements as shown in Table 1 below were added to promote the enrichment of biofilms, obtaining simulated wastewater (pH 7.45 ± 0.2). The inoculation amount of anaerobic granular sludge was VSS = 18.63 g / L, VSS / TSS = 0.6.

[0072] Table 1 Formulation of trace elements

[0073] Five experimental groups were set up, with three replicates for each group. The grouping schematic diagram is as Figure 2 shown. Specifically as follows: (1) Blank group: Add 50 mL of simulated wastewater to the anaerobic bottle; (2) Control group: Add 10 mL of anaerobic granular sludge and 50 mL of simulated wastewater to the anaerobic bottle; (3) Biochar group: Add 10 mL of anaerobic granular sludge, 50 mL of simulated wastewater and 0.5 g of biochar powder to the anaerobic bottle; (4) Zero-valent iron group: Add 10 mL of anaerobic granular sludge, 50 mL of simulated wastewater and 0.5 g of zero-valent iron to the anaerobic bottle; (5) Iron-modified biochar group: Add 10 mL of anaerobic granular sludge, 50 mL of simulated wastewater and 0.5 g of the iron-modified biochar prepared in Example 1 to the anaerobic bottle.

[0074] All samples were cultured at 36 ± 1 °C and 130 rpm for 60 days. Monitor the pH, SMX, sul1 , sul2 , intI1 , COD, VFAs, methane production and other indicators.

[0075] The results are as Figures 3 - 12 shown.

[0076] The SMX removal efficiency of the control group was 45.32%, that of the biochar group was 70.50%, that of the zero-valent iron group was 65.18%, and that of the iron-modified biochar group was 78.69%. Thus, it can be seen that the iron-modified biochar group has a much better SMX removal efficiency than the biochar group and the zero-valent iron group.

[0077] When the reaction ran for 60 days, the intI1The quantities are 9.30 × 10 4 copies / µL DNA, 5.15 × 10 4 copies / µL DNA, 5.92 × 10 4 copies / µL DNA, 4.96 × 10 4 copies / µL DNA. The relative removal efficiencies of the biochar group, zero-valent iron group, and iron-modified biochar group are 44.62%, 36.34%, and 46.67% respectively. The intI1 quantities of the control group, biochar group, zero-valent iron group, and iron-modified biochar group are 3.56 × 10 sul1 copies / µL DNA, 1.95 × 10 5 copies / µL DNA, 2.53 × 10 5 copies / µL DNA, 1.25 × 10 5 copies / µL DNA, 1.25× 10 5 copies / µL DNA. The relative removal efficiencies of the biochar group, zero-valent iron group, and iron-modified biochar group are 45.22%, 28.93%, and 64.89% respectively. The sul1 quantities of the control group, biochar group, zero-valent iron group, and iron-modified biochar group are 2.89 × 10 sul2 copies / µL DNA, 1.62 × 10 5 copies / µL DNA, 1.97× 10 5 copies / µL DNA, 1.33 × 10 5 copies / µL DNA, 1.33 × 10 5 copies / µL DNA. The relative removal efficiencies of the biochar group, zero-valent iron group, and iron-modified biochar group are 43.94%, 31.83%, and 53.98% respectively. Therefore, iron-modified biochar is more beneficial than biochar and zero-valent iron in reducing sul2 , intI1 , sul1 and sul2 quantities.

[0078] After the reaction ran for 60 days, the VFAs concentration in the control group was 874.5 mg / L, that in the biochar group was 328.1 mg / L, that in the zero-valent iron group was 242.6 mg / L, and that in the iron-modified biochar group was 162.8 mg / L. Compared with the control group, the VFAs removal efficiencies of the biochar group, the zero-valent iron group, and the iron-modified biochar group increased by 62.48%, 72.26%, and 81.38% respectively. Among them, compared with the control group, the relative acetic acid removal efficiencies of the biochar group, the zero-valent iron group, and the iron-modified biochar group were 58.22%, 68.49%, and 75.34% respectively. The relative propionic acid removal efficiencies of the biochar group, the zero-valent iron group, and the iron-modified biochar group were 68.89%, 77.78%, and 89.78% respectively. The relative butyric acid removal efficiencies of the biochar group, the zero-valent iron group, and the iron-modified biochar group were 64.29%, 71.43%, and 81.25% respectively. The relative valeric acid removal efficiencies of the biochar group, the zero-valent iron group, and the iron-modified biochar group were 64.72%, 77.29%, and 89.15% respectively. It can be seen that the iron-modified biochar group promoted the degradation of VFAs, and its degradation effect was better than that of the biochar group and the zero-valent iron group.

[0079] It can be seen from Figure 9 that the pH of the iron-modified biochar group was higher than that of the biochar group and the zero-valent iron group. This indicates that the iron-modified biochar group had better buffering capacity. The addition of iron-modified biochar enhanced the buffering capacity of the system, promoted the degradation of VFAs, and alleviated the decrease in pH.

[0080] [[ID=⑧]]After the reaction ran for 60 days, the methane production in the control group was 8.30 mL / g CODremoved, that in the biochar group was 19.01 mL / g CODremoved, that in the zero-valent iron group was 22.56 mL / g CODremoved, and that in the iron-modified biochar group was 28.03 mL / g CODremoved. It can be seen that the iron-modified biochar group had a higher methane production.

[0081] After 60 days of batch experiments, the microorganisms in the control group had relatively high abundances at the phylum level, mainly Euryarchaeota (12.23%), Thermotogota (4.11%), and Firmicutes (10.81%). In the biochar group, they were mainly Euryarchaeota (17.08%), Thermotogota (9.69%), and Firmicutes (7.99%). In the zero-valent iron group, they were mainly Euryarchaeota (18.24%), Thermotogota (8.97%), and Firmicutes (7.18%). In the iron-modified biochar group, they were mainly Euryarchaeota (19.37%), Thermotogota (10.5%), and Firmicutes (6.39%). The microorganisms in the control group had relatively high abundances at the genus level, mainly Methanobacterium (8.09%), AUTHM 297 (3.76%), Geobacter (0%), in the biochar group, they were mainly Methanobacterium (13.46%), AUTHM 297 (8.89%), Geobacter (2.76%), in the zero-valent iron group, they were mainly Methanobacterium (15.55%), AUTHM 297 (7.72%), Geobacter (3.43%), in the iron-modified biochar group, they were mainly Methanobacterium (17.32%), AUTHM 297 (10.69%), Geobacter (4.31%). It can be seen that the abundances of the dominant genera in the iron-modified biochar group were higher, and both the microbial abundance and diversity increased.

[0082] Detection Example 2 Using an anaerobic baffled reactor as the basic device, its structural schematic diagram is as Figure 13 shown. The material of the anaerobic baffled reactor is plexiglass, with an overall effective volume of 2.50 L, divided into 5 compartments, and the effective volume of each compartment is 0.50 L. The hydrothermal circulation pump can control the temperature of the AD system, and the temperature is set at 36 ± 1 °C. The simulated wastewater (the preparation method is the same as that in Detection Example 1, with the only difference being: the pH is 7.2; the COD and SMX of the substrate gradually increase according to the running time (such as Figure 14 and 15As shown, the COD was increased from 0 to 1800 ± 10 mg / L, and the SMX was increased from 0 to 150 ± 5 mg / L. It was stored in a feed tank with an effective volume of 10 L, and the influent flow rate was controlled by a feed pump. After the anaerobic baffled reactor was inoculated with anaerobic granular sludge (the VSS of the anaerobic granular sludge was 19.78 g / L, and VSS / TSS = 0.85), the hydraulic retention time was set to 24 h (each compartment contained 0.3 L of simulated wastewater and 0.2 L of anaerobic granular sludge), and the temperature was controlled at 36 ± 1 °C by a hydrothermal circulation pump. The first stage (days 1 - 100) was the start-up period and sludge acclimation period of the anaerobic baffled reactor; the second stage (days 101 - 181) was the stable period before intensification; the third stage (days 182 - 271) was the load increase stage after intensification. On day 181, 8 g of iron-modified biochar was added to each of the 5 compartments for intensification; the fourth stage (days 272 - 360) was the stable period after intensification. At the end of each stage, samples were taken to detect the removal efficiencies of SMX and COD in compartments C1, C2, C3, C4, and C5, and the degradation of sulfamethoxazole antibiotics and antibiotic resistance genes was monitored.

[0083] SMX removal efficiency (%) = (SMX 出水 - SMX 进水 ) / SMX 出水 ; COD removal efficiency (%) = (COD 出水 - COD 进水 ) / COD 出水 .

[0084] The results are shown in Table 2 and Figures 16 - 18 as follows.

[0085] Table 2

[0086] Although the influent SMX concentration increased from 120 mg / L in the second stage to 155 mg / L in the fourth stage, the SMX removal efficiencies of C1, C2, C3, C4, and C5 in the fourth stage were 35%, 36%, 35%, 31%, and 30% higher than those in the second stage; the COD removal efficiencies of C1, C2, C3, C4, and C5 in the fourth stage were 37%, 40%, 35%, 31%, and 23% higher than those in the second stage. Therefore, the iron-modified biochar significantly improved the removal efficiencies of SMX and COD.

[0087] IntI1 is the most important integron for horizontal gene transfer (HGT). In the second stage, sul1 the concentrations in C1, C2, C3, C4, and C5 were 3.71 × 10 6 , 2.93 × 106 , 2.14 × 10 6 , 1.42 × 10 6 , 1.05 × 10 6 copies / µL DNA. After adding iron-modified biochar, the removal efficiencies of sul1 in C1, C2, C3, C4, and C5 increased by 14.12%, 16.53%, 21.32%, 30.39%, and 39.31% respectively. Similarly, sul2 the removal efficiencies increased by 16.41%, 23.33%, 28.85%, 34.15%, and 43.33% respectively. In addition, intl1 the removal efficiencies increased by 19.54%, 26.42%, 30.58%, 35.57%, and 44.11% respectively.

[0088] The embodiments of the present invention have been described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention.

Claims

1. A preparation method of iron-modified biochar, characterized in that, It includes the following steps: Prepare a first mixture including an iron ion solution and biochar, react, dry to obtain a solid phase; under the atmosphere of nitrogen and / or inert gas, heat-treat the solid phase to obtain the iron-modified biochar.

2. The preparation method according to claim 1, characterized in that, The molar mass ratio of the iron ions to the biochar is 1.0 mmol - 2.5 mmol: 1 g; and / or, the temperature of the reaction is 20°C - 35°C; and / or, the time of the reaction is 12 h - 48 h.

3. The preparation method according to claim 1, characterized in that, The heating rate of the heat treatment is 5°C / min - 10°C / min; and / or, the treatment temperature of the heat treatment is 500°C - 600°C; and / or, the time of the heat treatment is 3 h - 6 h.

4. An iron-modified biochar, characterized in that, The iron-modified biochar is prepared by the preparation method according to any one of claims 1 to 3.

5. Use of the iron-modified biochar according to claim 4 in the treatment of wastewater containing sulfonamide antibiotics.

6. The application according to claim 5, wherein When the iron-modified biochar is applied to the treatment of wastewater containing sulfonamide antibiotics, it has at least one of the effects of A1) to A6): A1) Promote the removal of sulfonamide antibiotics; A2) Promote the removal of resistance genes; A3) Promote the removal of volatile fatty acids; A4) Promote methane production; A5) At the phylum level, enrich Euryarchaeota, Thermotogae, Firmicutes; A6) At the genus level, at least one of Methanobacterium, AUTHM , Geobacter is enriched. AUTHM 297, and Geobacter is enriched.

7. The application according to claim 6, wherein The sulfonamide antibiotics include at least one of sulfamethoxazole, sulfadiazine, sulfisoxazole, sulfamethazine, sulfamonomethoxine, sulfacetamide, sulfamerazine, sulfathiazole, sulfapyridine; and / or, the resistance genes include sulfonamide resistance genes; and / or, the volatile fatty acids include at least one of acetic acid, propionic acid, butyric acid, valeric acid.

8. A treatment method for wastewater containing sulfonamide antibiotics, characterized in that, It includes the following steps: Prepare a second mixture containing the iron-modified biochar according to claim 4, anaerobic microorganisms and wastewater containing sulfonamide antibiotics, and perform anaerobic treatment.

9. The processing method according to claim 8, wherein The COD of the wastewater containing sulfonamide antibiotics is 100 mg / L - 2000 mg / L; and / or, the mass ratio of C:N:P of the wastewater containing sulfonamide antibiotics is 300 - 500:3 - 5:1; and / or, the concentration of sulfonamide antibiotics in the wastewater containing sulfonamide antibiotics is 30 mg / L - 150 mg / L; and / or, the wastewater containing sulfonamide antibiotics includes: 0.1 mg / L - 0.2 mg / L of copper element, 0.05 mg / L - 0.09 mg / L of boron element, 0.5 mg / L - 0.8 mg / L of nickel element, 5 mg / L - 8 mg / L of H2SO4, 0.1 mg / L - 0.2 mg / L of manganese element, 0.2 mg / L - 0.5 mg / L of zinc element, 0.2 mg / L - 0.5 mg / L of cobalt element, 5 mg / L - 10 mg / L of iron element, 0.1 mg / L - 0.3 mg / L of aluminum element, 0.02 mg / L - 0.05 mg / L of molybdenum element.

10. The processing method according to claim 8, characterized in that, The temperature of the anaerobic treatment is 34°C - 37°C; and / or, the time of the anaerobic treatment is not less than 24 h.

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