Composite material for sulfonamide antibiotic treatment, preparation method and application

Abstract

The invention belongs to the technical field of biochar preparation, water treatment and new materials, and discloses a composite material for sulfonamide antibiotic treatment, a preparation method and application, and the preparation method comprises the following steps: preparing sludge biochar SBC; mnO2 coated OSBC is prepared; aminated PCA is prepared; pCA-MnO2 (at) OSBC is prepared; the preparation method comprises the following steps: cutting absorbent cotton, ultrasonically cleaning with deionized water, drying, dispersing PCA-MnO2 coated OSBC into a polyvinyl alcohol PVA solution, dipping the absorbent cotton, dropwise adding glutaraldehyde for crosslinking, curing, dipping into a PCA-MnO2 coated OSBC suspension, and carrying out freeze-drying heat treatment. The composite material disclosed by the invention has relatively stable physical properties and chemical properties, can be efficiently separated from an aqueous solution and recycled after being degraded, and can achieve a relatively good degradation effect in various typical real water bodies.

Description

Technical Field

[0001] The invention belongs to the technical fields of biochar preparation, water treatment and new materials, and in particular to a composite material for sulfonamide antibiotic treatment, a preparation method and application thereof. Background Art

[0002] Sulfonamide antibiotics are the first broad-spectrum veterinary antibiotics to be fully applied. Their global consumption accounts for up to 5.9%, making them the most widely used antibiotic category. Among them, sulfamethoxazole (SMX), as one of the most commonly used sulfonamide antibiotics, is widely used to treat respiratory, gastrointestinal and urinary tract infections. Due to the low metabolic efficiency of sulfamethoxazole in humans and animals, most of the unmetabolized sulfamethoxazole enters the environment through excrement. Sulfamethoxazole has a long environmental half-life (10-30 days) and high water solubility (869.5 mg / L), which leads to its widespread detection in various water bodies such as sewage, surface water, and groundwater. Especially in the aquaculture industry, the large-scale use of sulfonamide antibiotics makes aquaculture wastewater the main way for them to enter the environment. Therefore, it is urgent to develop a technology for the efficient removal of sulfonamide antibiotics. The current technology for the treatment of sulfonamide antibiotics in aquaculture wastewater faces three technical bottlenecks.

[0003] First, traditional wastewater treatment technologies have fundamental efficiency defects. The activated sludge method has a low removal rate of sulfonamide antibiotics in aquaculture wastewater (24%-36%), resulting in their continued discharge into natural water bodies. The high concentrations of organic matter and ammonia nitrogen in aquaculture wastewater further compete for reaction sites, resulting in the failure of biodegradation pathways. More seriously, sulfamethoxazole and its metabolic intermediates may induce the spread of antibiotic resistance genes (ARGs), forming secondary ecological risks.

[0004] In contrast, the peracetic acid (PAA)-based advanced oxidation process has attracted widespread attention because it can completely mineralize or convert pollutants into low-toxic products by generating free radicals. However, the peracetic acid (PAA) advanced oxidation system is limited by its insufficient environmental adaptability, and its practical application faces a stability barrier that cannot be ignored. Under the typical alkaline conditions of aquaculture wastewater, the half-life of PAA is less than 2 hours, and more than 80% of the oxidant is wasted due to spontaneous decomposition. Although existing studies have attempted to improve the stability of the PAA system by adding various chelating agents, these small molecule chelating agents are not only difficult to degrade, but also form more stable complexes with heavy metals, which in turn aggravates environmental risks. Therefore, finding cost-effective chelating agents to improve the degradation effect of PAA while avoiding the secondary ecological risks it brings has become an urgent problem to be solved.

[0005] Finally, it is difficult for existing catalytic materials to balance activity and sustainability. As the main byproduct of sewage treatment, residual sludge is considered to be an ideal material for preparing biochar because of its rich organic matter and porous structure. However, the catalytic activity sites of raw sludge biochar (SBC) are limited, and it needs to be properly modified to improve its performance. Nano-manganese dioxide (MnO 2 ) is considered an ideal PAA activator due to its excellent electron transfer ability, but the free nanoparticles have a serious tendency to agglomerate. 2 The above problems can be partially alleviated, but the biochar / MnO prepared by traditional high-temperature pyrolysis method 2 The composite material has a single pore structure and lacks effective metal anchoring points on the surface. In addition, powdered catalysts are difficult to recover in dynamic water flow, and existing immobilization technologies (such as silica gel embedding) will significantly reduce the flux due to carrier pore blockage, which cannot meet the large flow requirements of aquaculture wastewater treatment.

[0006] Existing attempts to improve the system have failed to solve the above problems. Therefore, it is urgent to develop a low-cost, green sludge biochar / MnO 2 The composite material synthesis method is to introduce an environmentally friendly complexing agent and PAA to form a stable composite oxidation system to further enhance the MnO 2 The biochar composite material / PAA technology has the ability to remove sulfonamide antibiotics from aquaculture wastewater, while improving its anti-interference and circulation capabilities in natural water bodies, and then develops technology that can efficiently and sustainably remove sulfonamide antibiotics from aquaculture wastewater, achieves waste treatment, and promotes the green and sustainable development of aquaculture wastewater treatment. Summary of the invention

[0007] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a composite material for sulfonamide antibiotic treatment, a preparation method and an application thereof.

[0008] The technical solution adopted by the present invention to solve the technical problem is:

[0009] A method for preparing a composite material for sulfonamide antibiotic treatment comprises the following steps:

[0010] S1, preparing sludge biochar SBC;

[0011] S2, immersing the SBC in acid, and performing microwave-assisted acid treatment in a microwave chemical reactor to obtain functionalized sludge biochar OSBC;

[0012] S3, the functionalized sludge biochar and the pore regulator were wet ball-milled in anhydrous acetone, the ball-milled product was evenly mixed with the manganese source, the crystal plane directing agent, the dispersant and the solvent, and the ultra-dense polycrystalline MnO was obtained by one-pot hydrothermal synthesis. 2Coating porous structure functionalized sludge biochar MnO 2 @OSBC;

[0013] S4, reacting protocatechuol PCA with ethylenediamine EDA under the catalysis of carbodiimide / succinimide (EDC / NHS), purifying by centrifugation precipitation with n-hexane, washing with anhydrous acetone and vacuum drying to obtain aminated PCA (PCA-NH 2 ;

[0014] S5, MnO 2 @OSBC and PCA-NH 2 The reaction was carried out in a carbodiimide / succinimide (EDC / NHS) system, centrifuged and washed, and then vacuum dried to obtain PCA-MnO 2 @OSBC;

[0015] S6, cut the absorbent cotton and clean it with deionized water ultrasonically, dry it for later use, and then 2 @OSBC was dispersed in polyvinyl alcohol (PVA) solution and ultrapure water to obtain PCA-MnO 2 Suspension of PVA solution of @OSBC and PCA-MnO 2 @OSBC water-based suspension, impregnated with absorbent cotton in PCA-MnO 2 @OSBC PVA solution suspension, add glutaraldehyde to crosslink and solidify, and then immerse the crosslinked absorbent cotton in PCA-MnO 2 @OSBC water-based suspension was freeze-dried and then heat-treated in an inert gas atmosphere to obtain cotton wool loaded protocatechol-MnO for the treatment of sulfonamide antibiotic aquaculture wastewater. 2 PCA-MnO / sewage sludge biochar composites 2 @OSBC / Cotton.

[0016] Further, in S1, the sludge biochar is prepared by pyrolyzing the sludge;

[0017] Before the sludge is subjected to pyrolysis treatment, the process also includes: collecting sludge from the sludge treatment system of the sewage treatment plant using solid-liquid separation equipment, washing the sludge with ultrapure water and freeze-drying the sludge until it reaches a constant weight state, removing soluble impurities and excess water therein, and obtaining pre-treated sludge; wherein the sludge has an organic matter content of 40-90%, a freeze-drying temperature of -60-10°C, and a freeze-drying vacuum of 10-100 Pa;

[0018] During the pyrolysis treatment of sludge: the heating rate is 5-20℃ / min; the pyrolysis is continued at 400-800℃ for 60-180 min; the pyrolysis atmosphere is inert gas; the gas flow rate is 0.05-0.4 L / min;

[0019] After the residual sludge is pyrolyzed, the process further includes: acid washing the pyrolysis product to remove the soluble ash therein, then washing it with ethanol and water alternately until the pH value of the filtrate is neutral, freeze drying it to constant weight, grinding and sieving it to obtain sludge biochar; wherein the acid used in the acid washing process is an inorganic acid; the freeze drying temperature is -60-10°C; the freeze drying vacuum degree is 10-100 Pa; and after grinding, passing through a 50-300 mesh sieve;

[0020] Alternatively, in S2, the acid is dilute nitric acid; the ratio of SBC to dilute nitric acid g:mL is 1-20:200; the mass concentration of dilute nitric acid is 20%-68%; the microwave treatment time is 0.1-2 h, and the microwave power is 100 W-600 W;

[0021] Alternatively, the functionalized sewage sludge biochar OSBC in S2 is also treated as follows:

[0022] The filtrate was rinsed alternately with ethanol and water until the pH of the filtrate was neutral, and then freeze-dried to constant weight and ground and sieved to obtain sludge biochar; wherein the freeze-drying temperature was -60-10°C; the freeze-drying vacuum was 10-100 Pa; and the sludge was ground and sieved through a 50-300 mesh sieve.

[0023] Furthermore, in S3, the functionalized sludge biochar OSBC and solid sodium chloride particles are placed in a zirconia ball mill, anhydrous acetone and zirconia grinding balls are added for wet ball milling, and the solvent is subsequently recovered by freeze drying; the ball milled product is then placed in a solution containing permanganate, sodium citrate, and polyethylene glycol for ultrasonic mixing, and then transferred to a reactor for hydrothermal synthesis under optimized hydrothermal synthesis conditions, and the solid is filtered to obtain the solid, washed with ultrapure water until the filtrate is colorless, dried, ground and sieved to obtain an ultra-dense polycrystalline structure MnO 2 Coating porous structure functionalized sludge biochar MnO 2 @OSBC;

[0024] Among them, solid sodium chloride is used as a soluble multi-level pore template agent for hydrothermal synthesis, potassium permanganate is used as a manganese source for the hydrothermal synthesis system, sodium citrate is used as a crystal plane director for the hydrothermal synthesis system, and polyethylene glycol PEG10000 is used as a dispersant for the hydrothermal synthesis system;

[0025] The mass ratio of solid sodium chloride to sludge biochar is 0.1-0.3:1; the mass ratio of acetone to sludge biochar is 3-5:1; the mass ratio of zirconium oxide grinding balls to sludge biochar is 5-50:1; the ball milling speed is 100-500 rpm; the ball milling time is 30-90 min; the freeze-drying temperature is -60-10°C; the freeze-drying vacuum is 10-100 Pa;

[0026] In step S3, the mass ratio of potassium permanganate to sludge biochar is 0.57-5.66:1; the molar concentration ratio of potassium permanganate to sodium citrate is 1-6:1; water is used in the one-pot hydrothermal synthesis, and the dosage ratio of sludge biochar to water is 1:10-100 in g:mL; the mass ratio of dispersant to sludge biochar is 0.1-10:1.

[0027] Alternatively, the mixture is uniformly mixed by ultrasound in S3;

[0028] Alternatively, the mass ratio of the dispersant to the sludge biochar is 0.1-10:1; the ultrasonic time is 10-30 min; the ultrasonic temperature is 20-80°C; the ultrasonic power is 100-300 W;

[0029] Alternatively, the temperature of the hydrothermal reaction in S3 is 110-200 °C, and the time of the hydrothermal reaction is 60 min-360 min;

[0030] Alternatively, the product after the one-pot hydrothermal synthesis in S3 is further treated as follows:

[0031] The product after one-pot hydrothermal synthesis was filtered, washed with water until the filtrate was colorless, freeze-dried to constant weight, and then ground and sieved to obtain ultra-dense polycrystalline MnO 2 Coated functionalized sludge biochar; wherein the freeze-drying temperature is -60-10°C; the freeze-drying vacuum degree is 10-100 Pa, and the sludge is ground and passed through a 50-200 mesh sieve.

[0032] Further, in S4, protocatechuol PCA and ethylenediamine EDA are dissolved in phosphate buffer, and EDC / NHS is added to react in the dark. After the reaction, the mixture is precipitated by n-hexane and centrifuged. The precipitate is collected and washed with anhydrous acetone, and then dried in vacuum to obtain aminated PCA, i.e., PCA-NH 2 ;

[0033] In the process of synthesizing aminated PCA: the pH of the phosphate buffer solution is 3-9; the volume of the phosphate buffer solution added to each 1.00 g of protocatechol is 60-200 mL; the molar ratio of PCA to EDA is 1:1-5; the molar ratio of EDC:NHS:PCA is 1-3:1-3:1; the reaction time is 4-24 h; the shaking rate is 100-200 rpm; the reaction conditions are room temperature and protected from light throughout the process;

[0034] Alternatively, the volume ratio of n-hexane to reaction liquid is 2-5:1; the centrifugation condition is 4000-8000 rpm; the centrifugation time is 10-30 min; the freeze-drying temperature is -60-10°C; the freeze-drying vacuum degree is 10-100 Pa;

[0035] Alternatively, S5 for PCA-MnO 2@OSBC is treated before reaction, including: 2 @OSBC and amino PCA were added to ultrapure water and thoroughly mixed by ultrasound. The ultrasound time was 10-30 min, the ultrasound temperature was 20-80℃, the ultrasound power was 100-300 W, and for every 1.00 g of MnO 2 @The volume of ultrapure water added to OSBC is 60-200 mL;

[0036] Alternatively, EDC and PCA-MnO in S5 2 The mass ratio of @OSBC is 1-3:1; the molar ratio of EDC to NHS is 1:1; the shaking rate is 100-200 rpm; PCA-NH 2 The solution concentration is 1-5 mg / mL; the reaction time is 12-48 h; the reaction conditions are room temperature and protected from light throughout the process;

[0037] After the reaction in the EDC / NHS system, the reaction solution was precipitated with anhydrous ethanol and centrifuged, the precipitate was collected and washed with anhydrous ethanol, and then vacuum dried to obtain PCA-MnO 2 @OSBC; wherein the volume ratio of anhydrous ethanol: reaction liquid is 2-5:1; the centrifugation condition is 4000-8000 rpm; the centrifugation time is 10-30 min; the freeze-drying temperature is -60-10℃; and the freeze-drying vacuum degree is 10-100 Pa.

[0038] Furthermore, in S6, the size of the cotton wool after cutting is 0.5 cm×0.5 cm to 2 cm×2 cm; the ultrasonic temperature is 20-80°C; the ultrasonic power is 100-300 W; the ultrasonic time is 10-30 min; the drying temperature is 50-80°C, the drying temperature is 60°C; and the drying time is 6-12 h;

[0039] Alternatively, the mass concentration of the polyvinyl alcohol (PVA) solution is 3-7%; the immersion time is 0.5-2 h; the added volume concentration of glutaraldehyde is 1-3%; the curing temperature is 50-70°C; the curing time is 1-3 h; PCA-MnO 2 The concentration of OSBC suspension is 0.5-2 mg / mL; the freeze-drying temperature is -60-10°C, the freeze-drying vacuum is 10-100 Pa; the heat treatment temperature is 100-150°C, the heat treatment time is 0.5-2 h; the inert gas is N 2 .

[0040] The absorbent cotton loaded protocatechol-MnO prepared by the preparation method described above for the treatment of sulfonamide antibiotic aquaculture wastewater 2 / sewage sludge biochar composites.

[0041] Cotton wool loaded with protocatechuol-MnO as described above 2 Application of sewage sludge biochar composites in the efficient activation of peracetic acid for the degradation of sulfonamide antibiotics in water.

[0042] The protocatechuol-MnO was loaded onto the absorbent cotton as described above. 2 A method for degrading sulfonamide antibiotics in water using a sewage sludge / biochar composite material comprises the following steps:

[0043] Cotton wool loaded with protocatechol-MnO 2 The / sludge biochar composite material is cut and added into an aqueous solution containing peracetic acid and sulfonamide antibiotics, and after the degradation process is completed, it is filtered to obtain a solution after the sulfonamide antibiotics are removed.

[0044] Further, the sulfonamide antibiotics include at least one of sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine, and sulfathiazole;

[0045] Alternatively, the concentration of sulfonamide antibiotics is 1-20 μmol / L; the concentration of peracetic acid is 100-800 μmol / L;

[0046] Alternatively, cotton wool loaded with protocatechuol-MnO 2 The dosage of sewage sludge biochar composite material is 0.1-0.8 g / L; the system pH is 1-14.

[0047] The protocatechuol-MnO was loaded onto the absorbent cotton as described above. 2 / sludge biochar composite material fixed bed system, the system includes a filling column, a peristaltic pump and a premixed solution introduction device, the filling column is filled with absorbent cotton loaded with protocatechol-MnO 2 / sludge-biochar composite material; the premix solution introduction device can contain PAA solution, the premix solution introduction device is connected to the input end of the filling column through a peristaltic pump, the premix solution introduction device can input the PAA solution into the filling column, and the aquaculture wastewater containing sulfamethoxazole is also connected to the input end of the filling column through another peristaltic pump, and the peristaltic pump inputs the aquaculture wastewater containing sulfamethoxazole into the filling column.

[0048] The advantages and effects achieved by the present invention are:

[0049] 1. The present invention obtains ultra-dense polycrystalline MnO by a one-pot hydrothermal synthesis method 2 Coated functionalized sludge biochar (MnO 2@OSBC), which can effectively reduce the energy consumed and synthesis cost during the synthesis process. The microwave chemical reactor is used to perform microwave-assisted dilute nitric acid functionalization on the sludge biochar. Through the selective heating and efficient energy transfer of microwaves, the modification efficiency of oxygen-containing functional groups on the biochar surface is significantly improved, and its surface roughness and pore structure are optimized, which provides a basis for the subsequent ultra-dense polycrystalline MnO 2 Covalent grafting of encapsulated and aminated protocatechol provides highly active attachment sites.

[0050] 2. Absorbent cotton loaded with protocatechol-MnO prepared by the present invention 2 / Sewage sludge biochar composite material has excellent physical and chemical properties, and can quickly activate low-concentration peracetic acid to efficiently degrade sulfonamide antibiotics in water. This process not only promotes the resource utilization of excess sludge, but also achieves the efficient removal of sulfonamide antibiotics in different water bodies, achieving the dual goals of waste resource utilization and environmental remediation.

[0051] 3. Ultra-dense polycrystalline structure MnO prepared by the present invention 2 The stable physical and chemical properties of the coated functionalized sludge biochar ensure that it can be effectively recovered after catalyzing the degradation of sulfonamide antibiotics by peracetic acid, thus realizing the recycling of the catalyst; in the presence of a variety of anions and within a wide pH range, the system can achieve good degradation effects, and has shown good sulfonamide antibiotic removal effects in a variety of actual water bodies, and has strong anti-interference ability.

[0052] 4. Compared with traditional MnO 2 Compared with other synthetic methods (such as oxidation-reduction method, roasting method and chemical precipitation method), the one-pot hydrothermal method adopted in the present invention significantly improves the reaction activity and efficiency under high temperature and high pressure conditions, and can prepare nano-scale, high-purity and excellent crystallinity MnO 2 By innovatively introducing sodium citrate as a crystal plane director, the MnO 2 The crystal growth direction is adjusted so that the highly active crystal face is exposed first, forming a nanosheet / nanowire structure with a specific morphology. The method of the present invention is conducive to the preparation of nano-scale MnO with narrow particle size distribution, high purity and high crystallinity. 2 , this crystal face controllable MnO 2 After being compounded with functionalized sludge biochar, the catalytic ability of the material can be effectively improved, while the cost of material synthesis can be effectively reduced, and the performance and application potential of the product can be improved.

[0053] 5. The present invention adopts the water-soluble NaCl template method and innovatively uses acetone as the wet ball milling medium. The extremely low solubility of NaCl in acetone (0.00004 g / 100g) forms a unique "solvent shielding effect" to construct a multi-level porous MnO with macropore-mesopore-micropore coordinated distribution in one step.2 @OSBC composites. Compared with traditional acid-washing templates (such as CaCO 3 Compared with the MnO 2 The risk of structural damage can be eliminated by precisely controlling the multi-level pore structure through the template dissolution-crystallization process, significantly improving the mass transfer efficiency. At the same time, this method can completely maintain the MnO 2 The coating structure of the active components significantly improves the performance of the material. The entire process does not require complicated post-processing, and the template can be removed by just washing with water, which has the outstanding advantages of being green and environmentally friendly and suitable for large-scale production.

[0054] 6. The present invention innovatively converts amino protocatechol (PCA-NH 2 ) is immobilized on the surface of the composite material through a covalent grafting strategy. Compared with the traditional physical adsorption method, the formation of an amide bond (-CO-NH-) significantly improves the stability of the active component. This step-by-step method solves the technical problems of many side reactions and low grafting rate in the traditional one-step coupling, significantly increases the PCA loading amount, and the formation of an amide bond significantly enhances the stability of the material.

[0055] 7. The absorbent cotton carrier composite process designed in the present invention adopts a three-stage loading process of "PVA cross-linking-vacuum adsorption-thermal curing". First, a cross-linking network is constructed on the surface of the absorbent cotton by PVA / glutaraldehyde to achieve primary fixation, and then the active material is deeply penetrated into the internal pores of the fiber by vacuum assistance. Finally, N 2 Atmosphere heat treatment enhances interfacial bonding. This multi-level loading strategy achieves uniform distribution of active components in the three-dimensional fiber network.

[0056] 8. The present invention innovatively integrates four key technologies, namely microwave-assisted functionalization, solvent-shielded ball milling, crystal-oriented hydrothermal treatment and covalent grafting, to form a complete "green preparation of biochar-based composite materials" technology system. There is a significant synergistic effect between the various process units: the oxygen-containing functional groups introduced by microwave treatment promote the 2 The NaCl template not only regulates the pore structure but also assists the MnO 2 Crystal form control; PVA and glutaraldehyde cross-linking enhances the mechanical properties and stability of the composite material while optimizing its adsorption properties.

[0057] 9. Ultra-dense polycrystalline structure MnO prepared by the present invention 2 Coated functionalized sludge biochar MnO 2 @OSBC can efficiently activate low-concentration peracetic acid, and the removal rates of 10 μmol / L sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine and sulfathiazole can reach 96.1%, 94.7%, 91.4%, 93.9% and 90.3% respectively within 15 min.

[0058] 10. Compared with other technologies (adsorption and microbial degradation, etc.), the ultra-dense polycrystalline MnO prepared by the present invention 2 Coated functionalized sludge biochar MnO 2 The @OSBC activated peracetic acid system can efficiently mineralize sulfonamide antibiotics. The mineralization rates of 10 μmol / L sulfamethoxazole, sulfamethoxazole, sulfacetamide, sulfadoxine, and sulfathiazole can reach 71.6%, 67.9%, 68.1%, 70.9%, and 65.5%, respectively, within 15 min. Most pollutants are converted into non-toxic and harmless CO 2 and H 2 O, achieving complete removal of sulfonamide antibiotics. At the same time, its high physical and chemical stability can achieve efficient separation from the aqueous solution after degradation and realize recycling, thereby reducing the generation of wastewater and environmental pollution, in line with the concept of sustainable development. This technology has the prospect of simple operation, low cost and large-scale application.

[0059] 11. Compared with conventional advanced oxidation, the present invention uses a covalent grafting strategy to immobilize protocatechuol (PCA) on absorbent cotton to load protocatechuol-MnO 2 / Sludge biochar composite material surface, as a water-soluble phenolic acid component, widely exists in a variety of plants and Chinese medicinal materials, it not only has antibacterial effect, but also has different degrees of antibacterial effect on a variety of bacteria, and also has antioxidant effect. In this system, the immobilization of PCA enhances the physical and chemical stability of the reaction system and improves its anti-interference ability against background components (such as inorganic ions and humic acid) in complex water bodies. In addition, the antioxidant properties of PCA help maintain free radicals in the system, reduce oxidative stress, and protect the catalyst from oxidative damage, thereby improving the activity and selectivity of the catalyst. This method is simple to operate, low-cost, and effective, and will not cause secondary pollution or ecological damage to the water body, showing its application potential in the field of water treatment.

[0060] 12. Absorbent cotton loaded with protocatechol-MnO prepared by the present invention 2 The sludge-biochar composite material has relatively stable physical and chemical properties, can be efficiently separated and recycled from the aqueous solution after degradation, and can achieve good degradation effects in a variety of typical real water bodies.

[0061] 13. The technology of the present invention has the prospect of simple operation, low cost and large-scale application. 2@OBRB / Cotton / PAA) based fixed bed system, even in complex aquaculture wastewater environment, the system can maintain a high degradation efficiency and show good anti-interference performance, which is particularly important for actual wastewater treatment. The system realizes continuous flow reaction by delivering premixed solution through peristaltic pump, which is easy to operate and control and suitable for industrial application.

[0062] 14. Absorbent cotton loaded with protocatechol-MnO 2 The sludge biochar composite material can be used in the treatment of sulfonamide antibiotic wastewater. At the same time, the appropriate device is selected to further enhance the degradation ability and anti-interference ability of the material, solving the problem of MnO 2 The technical problem that biochar composite materials are not effective enough in removing sulfonamide antibiotics in complex water bodies such as aquaculture wastewater. The synthesis method of the present invention can effectively reduce the energy consumed and synthesis cost in the synthesis process, while improving the performance and application potential of the product. It utilizes the through-hole structure and surface hydroxyl modification characteristics of the three-dimensional porous cellulose-based carrier to ensure a high recovery rate of the catalyst and keep the hydraulic flux stable.

[0063] 15. In the process of preparing the composite material, protocatechuol (PCA) is modified by amino modification (PCA-NH 2 ) and then covalently grafted to the biochar surface instead of direct physical adsorption. PCA itself contains phenolic hydroxyl (-OH) and carboxyl (-COOH), but its carboxyl (-COOH) cannot directly form a stable chemical bond with the functional groups on the biochar surface. After the biochar surface is treated with microwave-assisted acid, its main functional groups are -COOH / -OH. The present invention introduces amino groups (-NH 2 ), so that it can form a stable amide bond (-CO-NH-) with the carboxyl group (-COOH) on the surface of biochar. In the prior art, PCA is usually combined with biochar by physical adsorption. This combination is relatively loose and easy to fall off during subsequent processing or use, resulting in unstable performance of the composite material. The present invention, through amino modification, enables PCA to form a stable amide bond (-CO-NH-) with the carboxyl group on the surface of biochar, significantly enhancing the bonding strength between PCA and biochar, thereby improving the stability and durability of the composite material.

[0064] 16. In the method of the present invention, a carbodiimide / succinimide (EDC / NHS) catalytic system is used to promote the amination of protocatechol (PCA) and the grafting reaction with biochar. In step S4, the goal is to convert the carboxyl group (-COOH) of PCA into an amino group (-NH 2). EDC activates the -COOH of PCA to generate an unstable O-acylisourea intermediate, and NHS converts it into a stable active ester (PCA-NHS) to avoid side reactions. Subsequently, the active ester reacts with the -NH 2 Reaction to generate PCA-NH 2 Since PCA has low carboxyl reactivity, the efficiency of direct condensation with EDA is extremely low, while EDC / NHS can significantly increase the amination rate. In step S5, the goal is to convert PCA-NH 2 -NH 2 EDC first activates the -COOH of biochar to generate an active intermediate, and NHS stabilizes the intermediate to generate biochar-NHS active ester. Then, biochar-NHS reacts with PCA-NH 2 -NH 2 Reaction to form a covalent amide bond. Due to the large steric hindrance of -COOH on the biochar surface, it directly reacts with PCA-NH 2 The reaction efficiency is low, while EDC / NHS can greatly improve the grafting rate. If the amination step is skipped and the -COOH of PCA is directly used to react with the -OH of biochar, there will be many problems: the reaction efficiency is extremely low, the phenolic hydroxyl group (-OH) and the carboxyl group (-COOH) require a strong dehydrating agent (such as DCC) to condense, and there are many by-products; the steric hindrance is large, and the benzene ring structure of PCA hinders its -COOH from effectively contacting the surface groups of biochar; pH limitation, PAA activation is usually carried out under acidic conditions (pH is 3-5), while the direct condensation reaction requires a neutral / alkaline environment, resulting in poor compatibility. Compared with the prior art, the present invention achieves efficient and stable chemical bonding by adopting the EDC / NHS catalytic system, significantly improves the binding efficiency between PCA and biochar, reduces the generation of by-products, and overcomes the problems of steric hindrance and pH limitation. This precise surface modification method not only improves the fixation effect of PCA on the surface of biochar, but also effectively improves the surface properties of biochar, further improving the performance of the composite material. The preparation process of the present invention is simple to operate, has mild conditions, has good controllability, and can achieve precise regulation of the performance of the composite material. Due to the formation of a stable chemical bond between PCA and biochar, the mechanical properties, thermal stability and chemical stability of the composite material have been significantly improved, making it have potential application value in a wider range of fields.

[0065] 17. In step S6 of the method of the present invention, PVA (polyvinyl alcohol) and glutaraldehyde (GA) are used to crosslink PCA-MnO 2@OSBC is fixed to the cotton wool, and its core principle is based on polymer cross-linking chemistry and material composite reinforcement mechanism. The hydroxyl group (-OH) of PVA can react with the subsequently added glutaraldehyde (GA) to form a three-dimensional cross-linked network, thereby enhancing the mechanical strength of the composite material. As a dialdehyde cross-linking agent, glutaraldehyde's two aldehyde groups (-CHO) react with the hydroxyl groups of PVA and the hydroxyl groups of the cotton wool fibers to form stable ether bonds (-COC-). This double cross-linking effect includes: PVA-PVA cross-linking, that is, GA connects adjacent PVA molecular chains to form a dense network structure, PCA-MnO 2 @OSBC particles are wrapped in it; and PVA-cotton fiber cross-linking, that is, GA bridges the PVA layer and the absorbent cotton cellulose to achieve chemical bonding rather than physical adsorption. In addition, the present invention is cured at 60°C. Raising the temperature can not only accelerate the rate of acetalization reaction, but also evaporate excess water, promote the shrinkage of the cross-linked network, and further enhance the bonding strength of the composite material.

[0066] Compared with the prior art, the present invention has significant advantages. Traditional methods usually fix functional materials on substrates through physical adsorption or simple chemical treatment, but this method has problems such as low bonding strength, poor stability, and easy falling off. The present invention realizes the chemical bonding of PVA and absorbent cotton fibers through a dual cross-linking system of PVA and glutaraldehyde, forming a stable three-dimensional cross-linked network, which significantly improves the mechanical strength and stability of the composite material. In addition, the curing process at 60°C further optimizes the formation of the cross-linked network and enhances the bonding strength of the composite material, so that it has better performance and wider application prospects in practical applications.

[0067] 18. In the method of the present invention, the performance of the absorbent cotton is significantly improved through functional enhancement treatment. During the growth of cotton, it synthesizes cellulose through photosynthesis, and the hydroxyl groups (-OH) on the cellulose molecular chain exist as inherent functional groups. After pretreatment, a large number of cellulose hydroxyl groups (-OH) on the surface of the absorbent cotton are fully exposed. Subsequently, the cross-linking effect of glutaraldehyde (GA) is used to transform the originally inert absorbent cotton into an active interface, which is then bonded to the PVA / PCA-MnO 2 @OBRB forms a stable chemical bond. The cross-linked composite material can still maintain integrity under the impact of water flow, which is easy to recycle. Compared with the prior art, the present invention overcomes the problem that powdered catalysts are difficult to recycle in dynamic water flow, and at the same time avoids the problem of a significant decrease in flux due to carrier pore blockage in existing immobilization technologies (such as silica gel embedding), thereby failing to meet the large flow requirements of aquaculture wastewater treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 is a scanning electron microscope image (SEM) of Example 1 of the present invention; wherein, Figure 1 (a) is the scanning electron micrograph of the prepared sludge biochar (SBC). Figure 1 (b) Ultra-dense polycrystalline structure MnO 2 Coated functionalized sludge biochar (MnO 2 @OSBC) scanning electron microscope image, Figure 1 (c) Protocatechuol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC) scanning electron microscope image;

[0069] Figure 2 The dosage of SBC, functionalized sludge biochar (OSBC), and polycrystalline MnO in the present invention is 0.4 g / L. 2 (MnO 2 )、MnO 2 @OSBC, protocatechol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC) and cotton wool loaded with protocatechol-MnO 2 / sludge biochar composites (PCA-MnO 2 @OSBC / Cotton) Adsorption rate of 10 μmol / L sulfamethoxazole from 0 to 15 min;

[0070] Figure 3 The dosage of SBC, OSBC, MnO in the present invention is 0.4 g / L. 2 、MnO 2 @OSBC, PCA-MnO 2 @OSBC and PCA-MnO 2 @OSBC / Cotton degradation rate of 10 μmol / L sulfamethoxazole at a PAA concentration of 400 μmol / L with a degradation time of 0-15 min;

[0071] Figure 4 The monolithic system PCA-MnO in the present invention 2 @OSBC / Cotton (20 mg), PAA (concentration in the degradation system was 400 μmol / L) or binary system PCA-MnO 2 @OSBC / Cotton (20 mg) + PAA (concentration in the degradation system is 400 μmol / L) removal rate of 10 μmol / L sulfamethoxazole at the degradation time of 0-15 min;

[0072] Figure 5 PCA-MnO 2@OSBC / Cotton / PAA / system has a PAA concentration of 100-800 μmol / L and PCA-MnO 2 @The effect of the degradation time of 0-15 min on the removal rate of sulfamethoxazole with a concentration of 10 μmol / L when the dosage of OSBC / Cotton is 0.4 g / L;

[0073] Figure 6 PCA-MnO 2 @OSBC / Cotton / PAA system in PCA-MnO 2 @The effect of OSBC / Cotton dosage of 0.1-0.8 g / L and PAA concentration of 400 μmol / L on the removal rate of 10 μmol / L sulfamethoxazole when the degradation time is 0-15 min;

[0074] Figure 7 PCA-MnO 2 @The effect of OSBC / Cotton / PAA system on the removal rate of sulfamethoxazole with a concentration of 10 μmol / L at pH 3-11 and degradation time 0-15 min;

[0075] Figure 8 PCA-MnO 2 @The effect of OSBC / Cotton / PAA system on the removal rate of sulfamethoxazole with a concentration of 10 μmol / L at a humic acid concentration of 0-10 mg / L and a degradation time of 0-15 min;

[0076] Fig. 9 PCA-MnO 2 @OSBC / Cotton / PAA system in Na 2 CO 3 The effect of the concentration of 0, 1, 5 and 10 mmol / L and the degradation time of 0-15 min on the removal rate of 10 mg / L sulfamethoxazole;

[0077] Fig.10 PCA-MnO 2 @OSBC / Cotton / PAA system in NaHCO 3 The effect of the concentration of 0, 1, 5 and 10 mmol / L and the degradation time of 0-15 min on the removal rate of 10 mg / L sulfamethoxazole;

[0078] Fig.11 PCA-MnO 2 @OSBC / Cotton / PAA system in NaNO3 The effect of the concentration of 0, 1, 5 and 10 mmol / L and the degradation time of 0-15 min on the removal rate of 10 mg / L sulfamethoxazole;

[0079] Fig.12 PCA-MnO 2 @The effect of the OSBC / Cotton / PAA system on the removal rate of 10 mg / L sulfamethoxazole at NaCl concentrations of 0, 1, 5 and 10 mmol / L and degradation time of 0-15 min;

[0080] Fig.13 PCA-MnO 2 @OSBC / Cotton / PAA system in Na 2 SO 4 The effect of the concentration of 0, 1, 5 and 10 mmol / L and the degradation time of 0-15 min on the removal rate of 10 mg / L sulfamethoxazole;

[0081] Fig.14 PCA-MnO 2 @OSBC / Cotton's ability to regenerate and degrade sulfamethoxazole;

[0082] Fig.15 PCA-MnO 2 @The removal rate of sulfamethoxazole with a concentration of 10 μmol / L by the OSBC / Cotton / PAA system in typical natural water bodies such as Yangtze River water, Thomson Lake water, livestock breeding wastewater, outlet sewage, tap water and drinking water in 0-15 min;

[0083] Fig.16 The dosage of PCA-MnO in the present invention is 0.4 g / L 2 @OSBC / Cotton removal rate of 10 μmol / L sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine and sulfathiazole at a PAA concentration of 400 μmol / L and a degradation time of 0-15 min;

[0084] Fig.17 The dosage of MnO in the present invention is 0.4 g / L 2 @Degradation rate and mineralization rate of OSBC against 10 μmol / L sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine and sulfathiazole at a PAA concentration of 400 μmol / L and a degradation time of 0-15 min;

[0085] Fig.18 In the present invention, PCA-MnO2 @ Fixed bed system diagram designed based on OSBC / Cotton / PAA system;

[0086] Fig.19 In the present invention, PCA-MnO 2 @The removal rate of sulfamethoxazole in filtered aquaculture wastewater containing 10 μmol / L sulfamethoxazole in a fixed bed system designed based on the OSBC / Cotton / PAA system within the degradation time of 0-1440 min. DETAILED DESCRIPTION

[0087] The present invention will be further described below in conjunction with the embodiments. The following embodiments are descriptive rather than restrictive, and the protection scope of the present invention cannot be limited by the following embodiments.

[0088] The various experimental operations involved in the specific embodiments are all routine techniques in the art. For parts not specially annotated in this document, ordinary technicians in the art can implement them by referring to various commonly used reference books, scientific and technological literature or related instructions, manuals, etc. before the filing date of this invention.

[0089] A protocatechuol-modified polycrystalline manganese dioxide sludge biochar-loaded absorbent cotton composite material and a preparation method thereof, comprising the following steps:

[0090] S1, provide surplus sludge (SS) and surplus sludge biochar (SBC);

[0091] S2, immersing SBC in a certain proportion of acid, and performing microwave-assisted acid treatment at a certain temperature in a microwave chemical reactor to obtain functionalized sewage sludge biochar (OSBC);

[0092] S3, wet ball milling the functionalized sludge biochar and the pore regulator in acetone, mixing the ball milling product with the manganese source, the crystal plane directing agent, the dispersant and the solvent, and obtaining the ultra-dense polycrystalline MnO by hydrothermal synthesis reaction. 2 Coated functionalized sludge biochar (MnO 2 @OSBC);

[0093] S4, reacting protocatechuol (PCA) with ethylenediamine (EDA) in the presence of carbodiimide / succinimide (EDC / NHS) catalyst, purifying by centrifugation of n-hexane, washing with anhydrous acetone and vacuum drying to obtain aminated PCA (PCA-NH 2 );

[0094] S5, MnO 2 @OSBC and PCA-NH 2The reaction was carried out in an EDC / NHS system according to a certain mass ratio, purified by centrifugation with anhydrous ethanol, washed with anhydrous ethanol and then dried in vacuum to obtain protocatechol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC);

[0095] S6, cut the absorbent cotton and clean it with deionized water ultrasonically, dry it for later use, and then 2 @OSBC was dispersed in a certain concentration of polyvinyl alcohol (PVA) solution and ultrapure water, and cotton wool was immersed in the PVA solution. A certain concentration of glutaraldehyde (GA) was added for cross-linking, and the cross-linked cotton wool was solidified at a certain temperature. 2 @OSBC water-based suspension, freeze-dried N 2 The absorbent cotton loaded protocatechol-MnO was finally obtained by heat treatment under atmosphere. 2 / sludge biochar composites (PCA-MnO 2 @OSBC / Cotton).

[0096] In step S1 of the present invention, sludge biochar is prepared by pyrolyzing sludge.

[0097] Residual sludge is the main byproduct produced in the process of treating sewage by the activated sludge method in urban sewage treatment plants. It is an extremely complex heterogeneous body composed of organic fragments, inorganic particles, colloids, etc. Since residual sludge has a wide range of sources and is rich in organic matter and porous structure, it is considered to be an ideal material for preparing biochar. Compared with other sludges, the high organic matter characteristics of residual sludge provide a natural advantage for its pyrolysis conversion. These organic components mainly come from proteins, polysaccharides and lipids left over from microbial metabolism. They are easier to carbonize to form porous biochar during high-temperature pyrolysis. Primary sludge contains more fibers and inert inorganic particles, and the pyrolysis products often have low porosity and limited adsorption performance. Chemical sludge relies on the addition of coagulants to form precipitation, and its inorganic metal salts (such as aluminum and iron compounds) account for too high a proportion, which not only reduces the carbon yield from pyrolysis, but also may weaken the functionality of biochar due to the clogging of pores by metal oxides. Industrial sludge has complex sources and often carries heavy metals or difficult-to-degrade toxic organic matter. There is a risk of secondary release of pollutants during pyrolysis, and additional stabilization pretreatment is required, which greatly increases the technical threshold and cost.

[0098] Before subjecting the sludge to pyrolysis treatment, the method also includes: collecting sludge from the sludge treatment system of the sewage treatment plant using solid-liquid separation equipment, washing the sludge with ultrapure water and freeze-drying the sludge until it reaches a constant weight state, removing soluble impurities and excess water therein, and obtaining pretreated sludge; wherein the biomass raw material is sludge, and most preferably residual sludge; the sludge organic matter content is 40-90%, and most preferably is 60%; the freeze-drying temperature is -60-10°C, and most preferably is -45°C; the freeze-drying vacuum degree is 10-100 Pa, and most preferably is 15 Pa.

[0099] During the pyrolysis treatment of the sludge: the heating rate is 5-20°C / min, and 10°C / min is most preferred; the pyrolysis is continued at 400-800°C for 60-180 min, and 120 min at 600°C is most preferred; the pyrolysis atmosphere is an inert gas, and nitrogen is most preferred; the gas flow rate is 0.05-0.4 L / min, and 0.1 L / min is most preferred.

[0100] After the sludge is pyrolyzed, the method further includes: acid washing the pyrolysis product to remove the soluble ash therein, then washing it alternately with ethanol and water until the pH of the filtrate is neutral, freeze-drying it to constant weight, grinding and sieving it to obtain sludge biochar; wherein the acid used in the acid washing process is a common inorganic acid, most preferably hydrochloric acid; the freeze-drying temperature is -60-10°C, most preferably -45°C; the freeze-drying vacuum degree is 10-100 Pa, most preferably 15 Pa; and after grinding, passing through a 50-300 mesh sieve, most preferably a 150 mesh sieve.

[0101] In step S2 of the present invention, the functionalized sludge biochar is obtained by immersing the sludge biochar (SBC) obtained in S1 in a certain proportion of acid and performing microwave-assisted acid treatment at a certain temperature in a microwave chemical reactor.

[0102] In step S2, the sludge biochar is functionalized by using a microwave chemical reactor with the assistance of organic acid or inorganic acid.

[0103] Common inorganic acids (such as sulfuric acid, hydrochloric acid, nitric acid, etc.) usually functionalize the surface of sludge biochar through strong oxidation, oxidizing the carbon atoms of sludge biochar into oxygen-containing functional groups such as carboxyl (-COOH), hydroxyl (-OH) and carbonyl (-C=O), thereby increasing the surface polarity and hydrophilicity. The oxidation of acids will lead to microporation or etching of the surface of sludge biochar, increase its surface roughness, and thus provide a new source of MnO. 2Crystals provide attachment sites. The strong oxidizing property of inorganic acids can decompose and remove soluble impurities on the surface of sludge biochar, improving the surface cleanliness of the material. Common organic acids (such as oxalic acid, citric acid, acetic acid, etc.) usually functionalize the carbon fiber surface through a milder oxidation reaction. Organic acids introduce carboxyl groups (-COOH) on the carbon fiber surface through esterification or partial oxidation. These carboxyl groups can form hydrogen bonds or covalent bonds with sludge biochar carbon atoms. However, the oxidizing ability of organic acids is relatively weak, and the etching effect on the carbon fiber surface is small, and the MnO provided is relatively weak. 2 The crystal attachment sites are relatively limited. Dilute nitric acid is more preferred. Dilute nitric acid (HNO 3 ) is a strong oxidant with a high oxidation potential. Compared with dilute sulfuric acid and dilute hydrochloric acid, dilute nitric acid can react quickly at a lower temperature to generate a large number of oxygen-containing functional groups, which can achieve a more significant surface functionalization effect in a shorter time. Dilute nitric acid treatment can generate micropores and pits on the carbon fiber surface, significantly increase the surface roughness, and thus increase the MnO on the surface of sludge biochar. 2 In addition, the present invention uses microwave-assisted dilute nitric acid treatment technology to functionalize the sludge biochar. Compared with the traditional acid treatment method, microwave radiation can significantly enhance the oxidative effect of dilute nitric acid: on the one hand, the selective heating characteristics of microwaves enable the nitric acid molecules to be efficiently activated, and a large number of oxygen-containing functional groups (-COOH, -OH, etc.) can be quickly generated at a relatively low temperature of 80-120°C. The functionalization efficiency is greatly improved compared with conventional methods. -COOH serves as a covalent anchoring site, which can be used for the subsequent EDC / NHS-catalyzed amide bond grafting (PCA-NH 2 Modification) provides the necessary reactive groups, and -OH can pre-organize the orientation of PCA molecules through hydrogen bonds, promoting -NH 2 On the other hand, the bulk heating effect of microwaves promotes the uniform penetration of acid solution, forming a more uniformly distributed microporous structure and nanoscale roughness on the surface of biochar, which provides a basis for the subsequent MnO 2 The crystals provide more and more uniform attachment sites. At the same time, microwave-assisted treatment significantly shortens the reaction time, and the product of nitric acid reduction is only CO 2 and H 2 O, in line with the concept of green chemistry, produces fewer by-products and has little impact on the environment.

[0104] Before the sludge is functionalized, the method also includes: placing SBC and an acid solution of a certain concentration in a closed microwave reaction tank lined with polytetrafluoroethylene and ultrasonically mixing them evenly; wherein the ultrasonic time is 10-60 min, preferably 30 min; the ultrasonic temperature is 20-80°C, preferably 25°C; the ultrasonic power is 100-300 W, preferably 200 W.

[0105] In the process of functionalization treatment of sludge biochar: the acid is a diluted common organic acid or inorganic acid, most preferably dilute nitric acid; the ratio of SCB mass to dilute nitric acid volume is (1-20 g):200 mL, most preferably 5 g:200 mL; the mass concentration of dilute nitric acid is 20%-68%, most preferably 50%; the microwave treatment time is 0.1-2 h, most preferably 0.5 h, and the microwave power is 100 W-600 W, most preferably 300 W.

[0106] After the sludge is functionalized, the method further includes: washing with ethanol and water alternately until the pH of the filtrate is neutral, freeze-drying to constant weight, grinding and sieving to obtain sludge biochar; wherein the freeze-drying temperature is -60-10°C, preferably -45°C; the freeze-drying vacuum degree is 10-100 Pa, preferably 15 Pa; and grinding and sieving through a 50-300 mesh sieve, preferably a 150 mesh sieve.

[0107] In step S3 of the present invention, the functionalized sludge biochar (OSBC) obtained in step S2 and solid sodium chloride (NaCl) particles are placed in a zirconia ball mill, dehydrated acetone and zirconia grinding balls are added for wet ball milling, and the solvent is subsequently recovered by freeze drying. The ball milled product is then placed in a solution containing permanganate (KMnO 4 )、Sodium citrate(Na 3 C 6 H 5 O 7 ), dispersant, and solution were ultrasonically mixed, and then transferred to a reactor for hydrothermal synthesis under optimized hydrothermal synthesis conditions, and solids were filtered out, washed with ultrapure water until the filtrate was colorless, dried, ground and sieved to obtain ultra-dense polycrystalline MnO 2 Coated porous structure functionalized sludge biochar (MnO 2 @OSBC).

[0108] In step S3, solid sodium chloride is used as a soluble multi-level porous template agent for hydrothermal synthesis.

[0109] The particle size of solid sodium chloride (100-300 nm) directly regulates the macroporous structure (150±50 nm) of the final material. By using acetone as the wet ball milling medium and taking advantage of the extremely low solubility of NaCl in acetone (0.00004 g / 100g), the risk of dissolution is eliminated from a thermodynamic point of view. Through the action of high-energy mechanical forces, NaCl crystals are physically embedded in the pores and surface defects of biochar. At the same time, acetone molecules form an adsorption layer on the surface of NaCl crystals to prevent water molecules from contacting. NaCl can still maintain a complete crystal shape, which plays a solvent shielding effect and ensures that the NaCl crystals are intact and insoluble during the ball milling stage. In the hydrothermal reaction, NaCl forms through-channels through the dynamic dissolution-recrystallization equilibrium, which cooperates with the strong oxidizing property of potassium permanganate to finally obtain a macroporous-mesoporous multi-level structure and a loaded ultra-dense polycrystalline phase MnO 2 The green process fundamentally avoids the traditional acid-washing template method (such as CaCO 3 、SiO 2 The template needs to be treated with HF / HCl) to avoid environmental pollution. During the hydrothermal process, the soluble multi-level pore template agent gradually dissolves and can be completely removed by washing with warm water after the reaction without the need for complicated post-processing.

[0110] In step S3, a one-pot hydrothermal method is used to synthesize ultra-dense polycrystalline MnO 2 Coated functionalized sewage sludge biochar.

[0111] Compared with traditional MnO 2 Compared with the synthetic methods (such as redox method, roasting method and chemical precipitation method), the one-pot hydrothermal method can increase the solubility and activity of chemical reagents under high temperature and high pressure conditions, making some reactions that are not easy to occur at room temperature and pressure possible, thus broadening the preparation of MnO 2 This method is conducive to the preparation of nano-scale, narrow particle size distribution, high purity and high crystallinity MnO 2 , which can effectively reduce the energy consumed and synthesis cost in the synthesis process, while improving the performance and application potential of the product. 2 The crystallinity is poor and the single crystal form is poor. This means that the MnO prepared by the redox method 2 MnO may not have the ideal physical and chemical properties, affecting its performance in specific applications. 2 The morphology and size of MnO2 limit its use in applications that require specific structural materials. Although the calcination method is simple to operate, it has fewer manganese salts to choose from and a single raw material. This limits the regulation of MnO2 by changing the raw materials. 2 The possibility of properties. Sintering is likely to occur during high-temperature calcination, making it difficult to produce nano-scale MnO 2, and the particle size distribution is wide. This may lead to a reduction in the specific surface area and the number of active sites of the material, affecting its catalytic performance. Precipitates will be produced during the chemical precipitation process. In some cases, the physical properties of some precipitates are difficult to determine due to the different particle sizes and morphologies of the precipitates, which may affect subsequent processing or use. At the same time, the process requires the consumption of a large amount of chemicals, especially some chemicals may be affected by chemical reactions and consume more, which requires users to control the dosage, otherwise it will cause unnecessary waste. Since chemical precipitation is a method that relies on chemical reactions, this technology may not work for some substances, and other technologies are needed for separation and extraction.

[0112] In step S3, potassium permanganate is used as a manganese source in the hydrothermal synthesis system.

[0113] The manganese in potassium permanganate is at +7, which is the highest oxidation state of manganese and has a strong oxidizing ability. This strong oxidizing property makes it very suitable for the synthesis of nano-MnO 2 can be efficiently reduced, thus achieving rapid chemical reaction and uniform MnO 2 structure growth. Other common manganese sources (such as MnCl 2 、Mn(NO 3 ) 2 、MnSO 4 ) are usually in a lower oxidation state (+2 or +3) and require additional oxidants or more severe conditions to be oxidized to MnO 2 , the reaction process is more complicated. The reduction product of potassium permanganate is mainly CO 2 and H 2 O, harmless to the environment. Compared with other manganese sources, potassium permanganate does not release harmful gases or produce toxic byproducts during the reaction, which meets the requirements of green chemistry. 2 When Mn(NO 3 ) 2 May release nitrogen oxide gases, MnSO 4 Sulfur gases may be released, which may be potentially harmful to the environment and operators.

[0114] In step S3, sodium citrate is used as a crystal plane directing agent in the hydrothermal synthesis system.

[0115] Sodium citrate is a natural organic compound with good biocompatibility and environmental friendliness. It is mainly derived from the neutralization reaction of citric acid and is a renewable resource that conforms to the development concept of green chemistry. Compared with traditional reducing agents (such as hydrogen, sodium borohydride, hydrazine hydrate, etc.), sodium citrate does not produce harmful by-products or toxic gases during the reaction, which is safer for the environment and operators. Related studies have shown that the reduction process of sodium citrate can be carried out under relatively mild conditions, reducing energy consumption and potential hazards. The aqueous solution of sodium citrate is weakly alkaline, and the by-products generated after the reaction (such as CO 2 and H 2 O) It is harmless to the environment. The use of sodium citrate can reduce the cost of wastewater treatment and reduce environmental pollution. Sodium citrate is not only reductive, but also has a variety of chemical functional groups (such as carboxyl and hydroxyl), which can be used in the synthesis of crystalline MnO 2 In the process of sludge biochar, it coordinates with manganese ions, thus playing a role in surface regulation and stabilization, making the MnO coated on the surface of sludge biochar 2 At the same time, by regulating the MnO 2 The growth direction and morphology of the structure make the MnO synthesized on the surface of sludge biochar 2 The crystal types are more diverse, which effectively improves its catalytic performance. Sodium citrate has moderate reducing ability and can gradually reduce potassium permanganate under mild conditions, avoiding the side reactions or MnO that may be caused by overly strong reducing agents. 2 Crystal structure destruction. As a cheap and readily available chemical, sodium citrate has a market price much lower than many traditional reducing agents (such as sodium borohydride, hydrazine hydrate, etc.). In addition, the synthesis process of sodium citrate is simple and easy to produce on a large scale, which makes it have significant economic advantages in industrial applications.

[0116] In step S3, polyethylene glycol (PEG10000) is used as a dispersant in the hydrothermal synthesis system.

[0117] As a high molecular polymer, polyethylene glycol has good dispersibility and stability. During the ultrasonic treatment process, PEG can effectively disperse the biochar particles and prevent them from agglomerating and precipitating, thereby ensuring that the biochar particles are fully contacted and mixed with the manganese source and the reducing agent. The addition of PEG can increase the viscosity of the solution, which helps to slow down the rising speed of the bubbles generated during the ultrasonic treatment, allowing the bubbles to contact the biochar particles for a longer time, thereby improving the mixing effect. PEG itself may also interact with the surface of biochar to form a coating layer, changing the surface properties and structure of the biochar. This coating layer may help to further improve the catalytic performance of biochar. The molecular chain of PEG can interact with the manganese source to help the manganese source be evenly distributed on the surface of the biochar, thereby increasing the MnO 2More preferably, it is polyethylene glycol 10000.

[0118] In step S3, NaCl and sludge biochar are combined by wet ball milling with anhydrous acetone.

[0119] The mass ratio of solid NaCl template agent to sludge biochar is (0.1-0.3):1, and the most preferred is 0.15:1; the mass ratio of acetone solvent to sludge biochar is (3-5):1, and the most preferred is 4:1; the mass ratio of zirconium oxide grinding balls to sludge biochar is (5-50):1, and the most preferred is 20:1; the ball milling speed is 100-500 rpm, and the most preferred is 300 rpm; the ball milling time is 30-90min, and the most preferred is 60 min; the freeze-drying temperature is -60-10°C, and the most preferred is -45°C; the freeze-drying vacuum is 10-100 Pa, and the most preferred is 15 Pa.

[0120] In step S3, the mass ratio of potassium permanganate to sludge biochar is (0.57-5.66):1, and most preferably is 2.83:1; the molar concentration ratio of potassium permanganate to sodium citrate is (1-6):1, and most preferably is 3:1; the dosage ratio of sludge biochar to water is 1g:(10-100)mL, and most preferably is 1g:60mL; the mass ratio of dispersant to sludge biochar is (0.1-10):1, and further is 0.1:1.

[0121] In step S3, the mixture is mixed evenly by ultrasound.

[0122] The mass ratio of dispersant to sludge biochar is (0.1-10):1, and the most preferred is 0.1:1; the ultrasonic time is 10-30min, and the most preferred is 20 min; the ultrasonic temperature is 20-80°C, and the most preferred is 60°C; the ultrasonic power is 100-300 W, and the most preferred is 200 W.

[0123] In step S3, the temperature of the hydrothermal reaction is 110-200°C, most preferably 130°C, and the time of the hydrothermal reaction is 60 min-360 min, most preferably 120 min.

[0124] In step S3, after the hydrothermal reaction, the hydrothermal product is filtered, washed with water until the filtrate is colorless, freeze-dried to constant weight, and then ground and sieved to obtain ultra-dense polycrystalline MnO 2 Coated functionalized sludge biochar. The freeze-drying temperature is -60-10°C, preferably -45°C; the freeze-drying vacuum is 10-100 Pa, preferably 15 Pa, and the ground biochar is passed through a 50-200 mesh sieve, preferably a 100 mesh sieve.

[0125] In step S4 of the present invention, protocatechuol (PCA) and ethylenediamine (EDA) are dissolved in phosphate buffer (PBS) in a certain ratio, and carbodiimide / succinimide (EDC / NHS) is added to react in the dark. After the reaction is completed, ethanol precipitation is performed by centrifugation, the precipitate is collected and washed with ethanol, and then vacuum dried to obtain aminated PCA (PCA-NH 2 ).

[0126] Synthesis of aminated PCA (PCA-NH 2 ) process: the pH of the phosphate buffer solution is 3-9, and most preferably 5.5; the volume of the phosphate buffer solution added per 1.00 g of protocatechuol is 60-200 mL, and most preferably 100 mL; the molar ratio of PCA to EDA is 1:(1-5), and most preferably 1:3; the molar ratio of EDC:NHS:PCA is (1-3):(1-3):1, and most preferably 2:2:1; the reaction time is 4-24 h, and most preferably 12 h; the shaking rate is 100-200 rpm, and most preferably 150 rpm; the reaction conditions are room temperature and protected from light throughout the process.

[0127] The aminated PCA is subjected to post-reaction treatment, further comprising: centrifuging with n-hexane precipitation, collecting the precipitate and washing it with anhydrous acetone, and vacuum drying to obtain the aminated PCA; wherein the volume ratio of n-hexane: reaction liquid is (2-5):1, and most preferably 3:1; the centrifugation condition is 4000-8000 rpm, and most preferably 6000 rpm; the centrifugation time is 10-30 min, and most preferably 15 min; the freeze-drying temperature is -60-10°C, and most preferably -45°C; and the freeze-drying vacuum degree is 10-100 Pa, and most preferably 15 Pa.

[0128] In step S5 of the present invention, protocatechuol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC) by combining the ultra-dense polycrystalline structure obtained in S3 MnO 2 Coated porous structure functionalized sludge biochar (MnO 2 @OSBC) and the aminated PCA obtained in S4 (PCA-NH 2 ) is obtained by shaking reaction in a certain mass ratio in carbodiimide / succinimide (EDC / NHS) in the dark.

[0129] p-Protocatechuol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC) for pre-reaction treatment, including: ultra-dense polycrystalline structure MnO 2 Coated porous structure functionalized sludge biochar (MnO 2@OSBC) and aminated PCA (PCA-NH 2 ) is added to ultrapure water and thoroughly mixed by ultrasonication; wherein, the ultrasonication time is 10-30 min, preferably 20 min; the ultrasonication temperature is 20-80°C, preferably 25°C; the ultrasonication power is 100-300 W, preferably 200 W; for every 1.00 g of MnO 2 The volume of ultrapure water added to OSBC is 60-200 mL, and 100 mL is most preferred.

[0130] Synthesis of Protocatechol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC) process: EDC and PCA-MnO 2 The mass ratio of @OSBC is (1-3):1, preferably 2:1; the molar ratio of EDC to NHS is 1:1; the shaking rate is 100-200 rpm, preferably 150 rpm; PCA-NH 2 The solution concentration is 1-5 mg / mL, and the most preferred is 2.5 mg / mL; the reaction time is 12-48 h, and the most preferred is 24 h; the reaction conditions are room temperature and protected from light throughout the process.

[0131] p-Protocatechuol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC) for post-reaction treatment, further comprising: after the reaction, the reaction solution is precipitated and centrifuged with anhydrous ethanol, the precipitate is collected and washed with anhydrous ethanol, and vacuum dried to obtain protocatechol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC); wherein the volume ratio of anhydrous ethanol: reaction liquid is (2-5):1, and the most preferred is 3:1; the centrifugation condition is 4000-8000 rpm, and the most preferred is 6000 rpm; the centrifugation time is 10-30 min, and the most preferred is 15 min; the freeze-drying temperature is -60-10°C, and the most preferred is -45°C; the freeze-drying vacuum degree is 10-100 Pa, and the most preferred is 15 Pa.

[0132] In step S6 of the present invention, the cotton wool is cut and ultrasonically cleaned with deionized water, and then dried for later use. 2 @OSBC was dispersed in a certain concentration of polyvinyl alcohol (PVA) solution, impregnated with absorbent cotton, and a certain concentration of glutaraldehyde (GA) was added for cross-linking. After curing at a certain temperature, the cross-linked absorbent cotton was immersed in PCA-MnO 2 @OSBC suspension, freeze-dried N 2 The absorbent cotton loaded protocatechol-MnO was finally obtained by heat treatment under atmosphere. 2 / sludge biochar composites (PCA-MnO 2 @OSBC / Cotton).

[0133] The pre-reaction treatment of the absorbent cotton includes: cutting the absorbent cotton, ultrasonically cleaning it with deionized water, and drying it for later use; wherein the size of the absorbent cotton is 0.5 cm×0.5 cm to 2 cm×2 cm, and is most preferably 1 cm×1 cm; the ultrasonic temperature is 20-80°C, and is most preferably 60°C; the ultrasonic power is 100-300 W, and is most preferably 200 W; the ultrasonic time is 10-30 min, and is most preferably 20 min; the drying temperature is 50-80°C, and the drying temperature is 60°C; the drying time is 6-12 h, and is most preferably 8 h.

[0134] Synthetic cotton wool loaded with protocatechol-MnO 2 / sludge biochar composites (PCA-MnO 2 @OSBC / Cotton) process: PCA-MnO 2 @OSBC was dispersed in a certain concentration of polyvinyl alcohol (PVA) solution, impregnated with absorbent cotton, and a certain concentration of glutaraldehyde (GA) was added for cross-linking. After curing at a certain temperature, the cross-linked absorbent cotton was immersed in PCA-MnO 2 @OSBC suspension, freeze-dried N 2 The absorbent cotton loaded protocatechol-MnO was finally obtained by heat treatment under atmosphere. 2 / sludge biochar composites (PCA-MnO 2 @OSBC / Cotton); wherein the concentration of polyvinyl alcohol (PVA) solution is 3-7% (w / v), preferably 5%; the volume of PVA solution is 60-200 mL, preferably 100 mL; the immersion time is 0.5-2 h, preferably 1 h; the added concentration of glutaraldehyde (GA) is 1-3% (v / v), preferably 2%; the curing temperature is 50-70°C, preferably 60°C; the curing time is 1-3 h, preferably 2 h; PCA-MnO 2 The concentration of the OSBC suspension is 0.5-2 mg / mL, preferably 1 mg / mL; the freeze-drying temperature is -60-10°C, preferably -45°C; the freeze-drying vacuum is 10-100 Pa, preferably 15 Pa; the heat treatment temperature is 100-150°C, preferably 120°C; the heat treatment time is 0.5-2 h, preferably 1 h; the heat treatment atmosphere is an inert gas, preferably N 2 .

[0135] The present invention provides an absorbent cotton loaded with protocatechol-MnO 2 / sludge biochar composite material, the absorbent cotton loaded with protocatechol-MnO 2 The / sludge biochar composite material is provided by the absorbent cotton loaded with protocatechol-MnO 2 The preparation method of sewage sludge biochar composite material is obtained.

[0136] The present invention provides an absorbent cotton loaded with protocatechol-MnO 2 Application of biochar / sludge composite materials. 2 / sludge biochar composite material is used to efficiently activate peracetic acid to degrade sulfonamide antibiotics in water. 2 @The fixed bed system is designed based on the OSBC / Cotton / PAA system.

[0137] The sulfonamide antibiotics include at least one of sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine, sulfathiazole and the like.

[0138] In the degradation system, the concentration of sulfonamide antibiotics is 1-20 μmol / L, and most preferably 10 μmol / L.

[0139] In the degradation system, the concentration of peracetic acid is 100-800 μmol / L, and most preferably 400 μmol / L;

[0140] Cotton wool loaded with protocatechol-MnO 2 The dosage of the sewage sludge biochar composite material is 0.1-0.8 g / L, and the most preferred amount is 0.4 g / L; the system pH is 1-14, including but not limited to 3, 5, 7, 9, 11, etc., and is preferably 1-11.

[0141] In the fixed bed system, the peristaltic pump flow rate is 0.1-60 mL / min, and 10 mL / min is most preferred; the packed column length is 10-100 cm, and 30 cm is most preferred; the packed column radius is 0.5-10 cm, and 2 cm is most preferred.

[0142] The above ultra-dense polycrystalline structure MnO 2 The application of coated functionalized sludge biochar includes the following steps:

[0143] Cotton wool loaded with protocatechol-MnO 2 The sewage sludge biochar composite material is cut into a certain weight and added into an aqueous solution containing peracetic acid and sulfonamide antibiotics. After the degradation process is completed, it is filtered to obtain a solution after the sulfonamide antibiotics are removed.

[0144] Cotton wool loaded with protocatechol-MnO 2The sludge / biochar composite material is used as a filling material in the filling column and placed in the filling column. The filtered aquaculture wastewater containing sulfonamide antibiotics and peracetic acid solution are introduced into the filling column in a certain proportion through a peristaltic pump, and the liquid flowing out of the filling column is the wastewater after the sulfonamide antibiotics are removed.

[0145] Example 1

[0146] A kind of cotton wool loaded with protocatechol-MnO for sulfonamide antibiotic wastewater treatment 2 A method for preparing a sewage sludge biochar composite material comprises the following steps:

[0147] S1. Collect the residual sludge (SS) from the sludge treatment system using solid-liquid separation equipment, remove the impurities in the sludge and remove the non-degradable impurities (plastics, metals, stones). Then, rinse it three times with ultrapure water, freeze-dry it in a freeze dryer to constant weight (freeze-drying temperature is -45°C; freeze-drying vacuum is 15 Pa), and then transfer it to a high-temperature tube furnace (N 2 The flow rate was 0.1 L / min, and the heating rate was 10℃ / min) at 600℃ for 120 min, and then the pyrolysis product was immersed in HCl (1 mol / L) to remove the soluble ash, and then rinsed alternately with anhydrous ethanol and ultrapure water until the filtrate pH was neutral, freeze-dried to constant weight (freeze-drying temperature was -45℃; freeze-drying vacuum was 15 Pa), and ground through a 150-mesh sieve (0.106 mm) to obtain sludge biochar SBC. Among them, the remaining sludge came from the Tangxun Lake Municipal Wastewater Treatment Plant in Wuhan City, and its element content is shown in Table 1;

[0148] Table 1 Relative content of non-oxygen elements in excess sludge

[0149]

[0150] S2, SBC (mass 5.0 g) and HNO (mass concentration 50%) 3 The solution (200 mL) was placed in a sealed microwave reaction tank lined with polytetrafluoroethylene and ultrasonically mixed for 30 min, then transferred to a microwave chemical reactor and treated at 300 W for 0.5 h to introduce oxygen-containing functional groups and optimize the pore structure. The solution was then rinsed alternately with anhydrous ethanol and ultrapure water until the pH of the filtrate was neutral, and then freeze-dried to constant weight (freeze-drying temperature was -45 °C; freeze-drying vacuum was 15 Pa), ground and passed through a 150-mesh sieve to obtain functionalized sludge biochar OSBC.

[0151] S3, OSBC (mass 2.0 g), solid sodium chloride (mass 0.3 g), anhydrous acetone (mass 8 g) and zirconium oxide grinding balls (mass 40 g) were placed in a planetary ball mill equipped with a zirconium oxide ball mill for wet ball milling (ball milling speed 300 rpm, ball milling time 60 min), and the solvent and the mixture were recovered by freeze drying (freeze drying temperature -45 ° C; freeze drying vacuum degree 15 Pa). Subsequently, the ball milling product (mass 2 g), potassium permanganate (mass 5.66 g) and polyethylene glycol solution (mass 0.1 g, concentration 0.1 mmol / L) were transferred into 120 mL of ultrapure water and ultrasonically mixed for 30 min to obtain a mixture, and then sodium citrate solid (final concentration 0.1 mol / L) (Na 3 C 6 H 5 O 7 = 3.097 g) relative to KMnO 4 The solution was added with a controlled concentration ratio (i.e., 1:3) (final concentration of 0.3 mol / L) and stirred continuously, ultrasonicated for 5 min, and then transferred to a stainless steel autoclave with a high-pressure valve for hydrothermal synthesis. The hydrothermal synthesis was carried out at 130°C for 120 min, and the solid in the reactor was filtered after cooling to room temperature. The solid was washed with ultrapure water until the filtrate was colorless, and freeze-dried to constant weight (freeze-drying temperature was -45°C; freeze-drying vacuum was 15 Pa). After grinding the sample, it was passed through a 100-mesh sieve (0.15 mm) to obtain ultra-dense polycrystalline MnO 2 Coated functionalized sludge biochar MnO 2 @OSBC.

[0152] Accordingly, potassium permanganate (mass 5.66 g) and polyethylene glycol solution (mass 0.1 g, concentration 0.1 mmol / L) were respectively transferred into 120 mL of ultrapure water and mixed by ultrasound for 30 min to obtain a mixture, and then sodium citrate solid (final concentration 0.1 mol / L) (Na 3 C 6 H 5 O 7 = 3.097 g) relative to KMnO 4 The solution was added with a controlled concentration ratio (i.e., 1:3) (final concentration of 0.3 mol / L) to the solution with continuous stirring, ultrasonicated for 5 min, and then transferred to a stainless steel autoclave with a high-pressure valve for hydrothermal synthesis. The hydrothermal synthesis was carried out at 130°C for 120 min, and the solid in the reactor was filtered after cooling to room temperature. The solid was washed with ultrapure water until the filtrate was colorless, and freeze-dried to constant weight (freeze-drying temperature was -45°C; freeze-drying vacuum was 15 Pa). After grinding the sample, it was passed through a 100-mesh sieve (0.15 mm) to obtain a polycrystalline MnO 2 (MnO2 );

[0153] S4. Dissolve 1.00 g of protocatechuol (PCA) and 1.17 g of ethylenediamine (EDA) (the molar ratio of PCA to EDA is 1:3) in 100 mL of phosphate buffer (PBS, pH=5.5), add 2.49 g of carbodiimide (EDC) and 2.49 g of succinimide (NHS) (the molar ratio of EDC: NHS: PCA is 2:2:1) to catalyze the reaction, and shake the reaction at 25°C in the dark for 12 h. After the reaction, add 300 mL of n-hexane (purity ≥98%) to precipitate and centrifuge (6000 rpm, 10 min), collect the precipitate and wash it with anhydrous acetone three times, and then freeze-dry it in vacuum (freeze-drying temperature is -45°C; freeze-drying vacuum is 15 Pa) to obtain amino PCA (PCA-NH 2 );

[0154] S5, 1.00 g of ultra-dense polycrystalline MnO 2 Coated porous structure functionalized sludge biochar (MnO 2 @OSBC) and 0.25 g of aminated PCA (PCA-NH 2 ) was added to 100 mL of ultrapure water and mixed thoroughly by ultrasonication for 30 min. Then 2.00 g of carbodiimide (EDC) and 2.00 g of succinimide (NHS) were added to catalyze the reaction for 24 h. The reaction conditions were room temperature (25°C) and the reaction was kept away from light and shaken throughout the process. After the reaction, 300 mL of anhydrous ethanol was added and precipitated by centrifugation (6000 rpm, 10 min). The precipitate was collected and washed with anhydrous ethanol three times, and then vacuum-dried (freeze-dried at -45°C; freeze-dried at a vacuum degree of 15 Pa) to obtain protocatechuol-MnO 2 / sewage sludge biochar (PCA-MnO 2 @OSBC);

[0155] S6. Cut the cotton wool into 1 cm × 1 cm size, place it in deionized water, and use an ultrasonic cleaner to ultrasonically clean it at 60°C with a power of 200 W for 20 min. Then, dry the cleaned cotton wool at 60°C for 8 h for later use. 2 @OSBC was dispersed in 100 mL of 5% (w / v) polyvinyl alcohol (PVA) solution and 100 mL of ultrapure water at a concentration of 1 mg / mL to obtain PCA-MnO 2 Suspension of PVA solution of @OSBC and PCA-MnO 2 @OSBC water-based suspension (this step will immerse PCA-MnO twice 2@OSBC suspension, first PCA-MnO 2 The suspension of PVA solution of @OSBC, the solvent is 5% (w / v) polyvinyl alcohol (PVA) solution, followed by PCA-MnO 2 @OSBC water-based suspension, the solvent is ultrapure water). The pretreated absorbent cotton is impregnated with PCA-MnO 2 @OSBC in a suspension of PVA solution, soaked for 1 h, then added 2% (v / v) glutaraldehyde (GA) solution for cross-linking, and cured at 60 °C for 2 h before rinsing the uncross-linked PVA with deionized water. Then, the cross-linked absorbent cotton was immersed in 100 mL of 1 mg / mL PCA-MnO 2 @OSBC water-based suspension, and then placed in a freeze dryer for freeze drying and solidification (freeze drying temperature is -45°C; freeze drying vacuum degree is 15 Pa). 2 The dried cotton wool was heat treated at 120 °C for 1 h under an atmosphere to obtain cotton wool loaded with protocatechol-MnO 2 / sludge biochar composites (PCA-MnO 2 @OSBC / Cotton).

[0156] Example 2

[0157] This example investigates the sludge biochar (SBC), ultra-dense polycrystalline MnO 2 Coated porous structure functionalized sludge biochar (MnO 2 @OSBC) and protocatecholate-MnO 2 Surface morphology of sewage sludge biochar composites, including:

[0158] Scanning electron microscope images clearly show the original sludge biochar, ultra-dense polycrystalline structure of MnO 2 Coated functionalized sludge biochar and ultra-dense polycrystalline MnO after reaction 2 Surface morphology of coated functionalized sludge biochar. Figure 1 (a) It can be seen that the surface of the original sludge biochar is relatively rough and has less pore structure, resulting in a low specific surface area and limited defect structure, which limits its catalytic efficiency. As the main by-product of anaerobic digestion, the residual sludge is rich in organic matter. The organic matter content in the sludge has a significant effect on the properties of the prepared biochar. Generally, sludge with high organic matter content can usually produce biochar with rich surface functional groups, good thermal stability and excellent application performance. In contrast, Figure 1 (b) It can be seen that the ultra-dense polycrystalline structure of MnO 2 The surface of the functionalized sludge biochar was coated with fibrous, network and nanoflower-like MnO 2This polycrystalline structure not only significantly increases the specific surface area of ​​the material, but also provides more active sites, thereby greatly improving the catalytic activity. 2 The excellent catalytic performance of the material further enhances the catalytic efficiency. By controlling the molar ratio of sodium citrate to potassium permanganate, the polycrystalline MnO 2 The surface roughness and activation ability of sludge biochar can be significantly improved by regulating the morphology. 2 In addition, the surface of sludge biochar was treated with dilute nitric acid, which enhanced the hydrophilicity of the surface of sludge biochar by introducing oxygen-containing functional groups (such as carboxyl-COOH, hydroxyl-OH and carbonyl-C=O), thereby enhancing its affinity with MnO. 2 The oxidation treatment produces tiny etching or pits on the surface of sludge biochar, increasing the surface roughness and providing a new interface bonding strength for MnO 2 It provides more contact points and anchor points, allowing it to better penetrate and adhere to the surface of the sludge biochar, significantly improving the overall performance of the composite material. Figure 1 (c) It can be seen that PCA is covalently grafted onto the ultra-dense polycrystalline structure of MnO 2 After coating the surface of functionalized sludge biochar, the surface morphology of the material did not change significantly, indicating that MnO 2 The stability of the biochar substrate is crucial for maintaining the long-term catalytic activity of the material.

[0159] Example 3

[0160] This example explores the effects of SBC, OSBC, and MnO 2 、MnO 2 @OSBC, PCA-MnO 2 @OSBC and PCA-MnO 2 @OSBC / Cotton The removal rate of sulfamethoxazole at different PAA contents, including:

[0161] Considering that biochar may have a certain adsorption effect on pollutants, 20 mg of SBC, OSBC, MnO 2 、MnO 2 @OSBC, PCA-MnO 2 @OSBC and PCA-MnO 2@OSBC / Cotton was added with sulfamethoxazole (the concentration in the adsorption system or degradation system was 10 μmol / L) in the absence of PAA. The adsorption system or degradation system was 50 mL of ultrapure water, and the pH of the solution was 7.71 (simulating actual aquaculture wastewater). It was stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken at the set time (0-15 min), and the residual concentration of sulfamethoxazole was determined by HPLC-MS, and the removal rate of sulfamethoxazole at different times was calculated.

[0162] Depend on Figure 2 It can be seen that in SBC, OSBC, MnO without PAA 2 、MnO 2 @OSBC, PCA-MnO 2 @OSBC and PCA-MnO 2 The removal rates of sulfamethoxazole in the @OSBC / Cotton system were 5.0%, 6.4%, 2.7%, 13.3%, 8.1% and 18.9%, respectively, which showed that SBC, OSBC, MnO 2 and PCA-MnO 2 @OSBC has limited adsorption capacity for sulfamethoxazole. This low adsorption rate may be due to the fact that the electrostatic interactions, pore filling, hydrophobic interactions, hydrogen bonds and π-π interactions between the functional groups and pore structures on the surface of these materials and sulfamethoxazole are not obvious or insufficient to overcome the solubility and stability of sulfamethoxazole, resulting in sulfamethoxazole molecules not being easily stably adsorbed on the surface of the material. In contrast, MnO 2 @OSBC and PCA-MnO 2 @OSBC / Cotton has a higher adsorption rate. MnO 2 The improvement in the adsorption rate of @OSBC can be attributed to the use of solid sodium chloride as a soluble hierarchical pore template for hydrothermal synthesis. The particle size of solid sodium chloride (100-300 nm) directly regulates the macroporous structure of the final material (150±50 nm). By using acetone as the wet ball milling medium and taking advantage of the extremely low solubility of NaCl in acetone (0.00004 g / 100g), the risk of dissolution is thermodynamically eliminated. Under the action of high-energy mechanical forces, NaCl crystals are physically embedded in the pores and surface defects of biochar. At the same time, acetone molecules form an adsorption layer on the surface of NaCl crystals, preventing water molecules from contacting, keeping NaCl in a complete crystalline shape, and playing a solvent shielding effect, ensuring that the NaCl crystals are intact and insoluble during the ball milling stage. PCA-MnO 2 The improvement of the adsorption rate of @OSBC / Cotton is due to the use of absorbent cotton loaded with protocatechol-MnO 2 / Three-dimensional porous cellulose-based carrier constructed by sludge biochar. Its unique structure and modification treatment provide a large specific surface area and good permeability, reduce the risk of pore blockage, and maintain high flux and treatment efficiency. This design not only enhances the material's adsorption capacity for sulfamethoxazole, but also ensures the stability and recyclability of the catalyst in dynamic water flow, overcoming the problems of traditional powdered catalysts being difficult to recycle and the flux reduction of immobilization technology.

[0163] At the same time, it can also be seen that the OSBC and the polycrystalline structure MnO 2 There is a synergistic effect between the two, which can synergistically improve the prepared PCA-MnO 2 @OSBC / Cotton related properties. It can also be seen that the protocatechuol and the absorbent cotton in the present invention have a synergistic effect, which can synergistically improve the prepared PCA-MnO 2 @OSBC / Cotton's related properties.

[0164] Depend on Figure 3 It can be seen that when the concentration of peracetic acid (PAA) is 400 μmol / L, SBC / PAA, OSBC / PAA, MnO 2 / PAA、MnO 2 @OSBC / PAA, PCA-MnO 2 @OSBC / PAA and PCA-MnO 2 The degradation rates of sulfamethoxazole by the @OSBC / Cotton / PAA degradation systems were 5.0%, 20.7%, 26.6%, 55.8%, 84.4% and 96.1%, respectively. The degradation rates of sulfamethoxazole by the degradation systems varied. 2 @OSBC / Cotton / PAA has the highest degradation rate and degradation rate for sulfamethoxazole. This result shows that MnO 2 @OSBC activated PAA played a key role in the degradation of sulfamethoxazole, which may be PCA-MnO 2 The interaction between the functional groups on the surface of @OSBC / Cotton and PAA promoted the oxidative decomposition of sulfamethoxazole. 2 @OSBC / Cotton / PAA has potential application value in the treatment of sulfonamide antibiotic pollutants. However, when protocatechuol is not grafted on the surface of the material, MnO 2@OSBC / PAA may have poor stability and regeneration ability, and the activation sites lose their activity after activating PAA, limiting its application in continuous degradation processes. Protocatechuol, as an organic chelating agent, can promote the adsorption of sulfamethoxazole by manganese-modified biochar, increase the local concentration of pollutants on the catalyst surface, thereby enhancing the activation effect and degradation efficiency of PAA. At the same time, it can effectively prevent the precipitation of transition metals in non-acidic environments and maintain the dissolved state of metal ions, which is crucial for metal-catalyzed redox reactions. The formed coordination field may affect the redox characteristics of manganese ions, thereby promoting the activation of PAA and the degradation of sulfamethoxazole. At the same time, PCA-MnO 2 The degradation rate and efficiency of @OSBC / Cotton / PAA system are significantly higher than those of MnO 2 / PAA, which is due to the single MnO 2 In aqueous solution, it may easily aggregate, reducing the accessibility of active sites, while biochar is MnO 2 Provides a large number of attachment sites, making MnO 2 This dispersion helps to increase the MnO 2 The contact area between biochar and PAA and pollutants (such as sulfamethoxazole) was increased, thereby improving the activation efficiency. 2 There is a synergistic effect between the PCA-MnO and the absorbent cotton, which has a higher specific surface area and a more suitable pore structure, and performs better in terms of stability and regeneration ability, which helps to maintain long-term activation efficiency. The three-dimensional porous cellulose-based structure of the absorbent cotton is 2 @OSBC provides abundant attachment sites, enabling it to be evenly dispersed on the carrier, preventing the agglomeration of the active ingredients, thereby increasing the accessibility of the active sites. 2 There is a synergistic effect between them. Its three-dimensional porous structure not only increases the specific surface area, but also provides a more suitable pore structure, which is conducive to the adsorption and degradation of pollutants, and performs better in terms of stability and regeneration ability. The three-dimensional porous structure of the absorbent cotton helps pollutants in the water to diffuse quickly to the catalyst surface, increasing the contact opportunity between sulfamethoxazole and the active sites, thereby accelerating the degradation reaction.

[0165] At the same time, it can also be seen that the protocatechuol and peracetic acid in the present invention have a synergistic effect, which can synergistically improve the prepared PCA-MnO 2 @OSBC / Cotton's related properties.

[0166] Example 4

[0167] This example explores the removal rates of sulfamethoxazole at different times in a mono-system and a binary system, including:

[0168] Unary system PCA-MnO 2 @OSBC / Cotton (20 mg), PAA (concentration in the degradation system was 400 μmol / L) or binary system PCA-MnO 2 @OSBC / Cotton (20 mg) + PAA (the concentration in the degradation system was 400 μmol / L) was added with sulfamethoxazole (the concentration in the degradation system was 10 μmol / L), the degradation system was 50 mL of ultrapure water, the solution pH was 7.71 (simulating actual aquaculture wastewater), and it was stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken at the set time (0-15min), and the residual concentration of sulfamethoxazole was determined by HPLC-MS, and the removal rate of sulfamethoxazole at different times was calculated.

[0169] Depend on Figure 4 It can be seen that PCA-MnO 2 @OSBC / Cotton (20 mg), PAA and PCA-MnO 2 The removal rates of sulfamethoxazole by @OSBC / Cotton / PAA system were 18.9%, 2.3% and 96.1% respectively. 2 The removal rate and removal efficiency of @OSBC / Cotton (20 mg) + PAA (the concentration in the degradation system is 400 μmol / L) for sulfamethoxazole are significantly higher than those of other systems. The removal efficiency of sulfamethoxazole can reach 96.1% after 15 min of reaction. This shows that PCA-MnO 2 @OSBC / Cotton can effectively activate peracetic acid to achieve efficient degradation of sulfamethoxazole. Specifically, the ultra-dense polycrystalline structure of MnO 2 Coating on functionalized sludge biochar provides more active sites and improves dispersion, which helps to improve the activation efficiency of PAA. 2 The synergistic effect between PCA and biochar can enhance the activation ability of PAA and produce more reactive oxygen species, such as hydroxyl radicals and sulfate radicals. PCA, as a natural polyphenol, can react with MnO 2 The complex formation can change the MnO 2 The electronic structure of PCA-MnO can be enhanced. 2@OSBC material is evenly distributed in the fiber structure of the cotton wool. This carrier property enables the cotton wool to provide stable support for the composite material while maintaining its porous structure, which is conducive to the adsorption and catalytic performance. Previous studies have shown that after PCA is complexed with metal ions, the removal effect of the catalytic system on sulfonamide antibiotics can be significantly improved in a wider pH range. MnO 2 Coating on biochar can improve the stability and regeneration ability of the material, slow down the reaction rate drop caused by catalyst poisoning, and the porous structure of biochar and the presence of PCA can enhance the adsorption capacity of sulfamethoxazole, making more sulfamethoxazole molecules close to the catalyst surface, thereby improving the degradation efficiency. 2 @OSBC / Cotton / PAA) has shown great potential and advantages in the treatment of sulfonamide antibiotic pollutants, and is expected to provide a new and efficient method for environmental pollution control.

[0170] Example 5

[0171] This example explores the effect of peracetic acid concentration on the removal of sulfamethoxazole in a ternary system, including:

[0172] Binary system (PCA-MnO 2 @OSBC / Cotton / PAA) PCA-MnO 2 The dosage of @OSBC / Cotton was 20 mg, the concentration of sulfamethoxazole was 10 μmol / L, the degradation system was 50 mL of ultrapure water, the solution pH was 7.71 (simulating actual aquaculture wastewater), the peracetic acid concentrations were set to 100, 200, 400, 600 and 800 μmol / L, respectively, and stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken at the set time (0-15 min), and the residual concentration of sulfamethoxazole was determined by HPLC-MS to explore the effect of peracetic acid concentration on the removal of sulfamethoxazole in the ternary system.

[0173] Depend on Figure 5 It can be seen that when the peracetic acid concentration is set to 100, 200, 400, 600 and 800 μmol / L, the binary system PCA-MnO 2 The removal rates of sulfamethoxazole by @OSBC / Cotton / PAA were 91.1%, 92.4%, 96.1%, 87.9% and 92.8%, respectively. The removal rate of sulfamethoxazole by this binary system was closely related to the concentration of peracetic acid. When the concentration of peracetic acid was too low, there was a lack of sufficient oxidant to react with PCA-MnO 2@OSBC / Cotton surface active sites or functional groups react effectively. Due to insufficient PAA concentration, the active sites on the catalyst surface cannot be fully utilized, resulting in low degradation efficiency. When the concentration of peracetic acid reaches 400 μmol / L, PCA-MnO 2 The active sites of the @OSBC / Cotton catalyst tend to be saturated. At this concentration, further increase of PAA did not significantly improve the degradation efficiency of sulfamethoxazole, indicating that the maximum utilization of the active sites on the catalyst surface has been reached and the reaction efficiency cannot be further improved by increasing the PAA concentration. When the PAA concentration is high, the effect is not significantly improved, but slightly decreased. This may be due to the excessive accumulation of reactive oxygen species (ROS) in the solution caused by the high PAA concentration. These ROS may quench each other, reducing the number of effective ROS that can be used to degrade sulfamethoxazole. Considering the removal effect and economy, a peracetic acid concentration of 400 μmol / L was selected as the additive dosage of the degradation system.

[0174] Example 6

[0175] This example explores the PCA-MnO 2 The effect of OSBC / Cotton dosage on the removal of sulfamethoxazole includes:

[0176] Binary system (PCA-MnO 2 @OSBC / Cotton / PAA) with a PAA concentration of 400 μmol / L and a sulfamethoxazole concentration of 10 μmol / L. The degradation system was 50 mL of ultrapure water and the solution pH was 7.71 (simulating actual aquaculture wastewater). 2 The dosage of @OSBC / Cotton was set to 0.1, 0.2, 0.4, 0.6 and 0.8 g / L, respectively, and stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken at the set time (0-15 min), and the residual concentration of sulfamethoxazole was determined by HPLC-MS to explore the PCA-MnO 2 Effect of the dose of @OSBC / Cotton on the removal of sulfamethoxazole.

[0177] Depend on Figure 6 It can be seen that when PCA-MnO 2 When the dosage of @OSBC / Cotton was set to 0.1, 0.2, 0.4, 0.6 and 0.8 g / L, the binary system PCA-MnO 2The removal rates of sulfamethoxazole by @OSBC / Cotton / PAA were 69.5%, 81.1%, 96.1%, 96.4% and 96.5%, respectively. The removal rate of sulfamethoxazole by the binary system increased with the increase of PCA-MnO 2 @OSBC / Cotton increases with the dosage. 2 When the dosage of @OSBC / Cotton was 0.4-0.8 g / L, there was no significant difference in the removal rate of sulfamethoxazole after 15 min of reaction, and both achieved a high removal efficiency, indicating that within this dosage range, further increasing the dosage had limited effect on improving the removal rate. 2 When the dosage of @OSBC / Cotton reached 0.4 g / L, there were enough active sites in the system to fully activate PAA, so that the oxidation potential of PAA was maximized, thus achieving efficient degradation of sulfamethoxazole. 2 When the dosage of @OSBC / Cotton was further increased to 0.6 and 0.8 g / L, although the total amount of catalyst increased, the concentration of PAA remained unchanged, which means that the additional PCA-MnO 2 @OSBC / Cotton did not provide more effective active sites for PAA activation, but may have led to redundancy of some active sites. In this case, the activation efficiency of PAA and the amount of ROS generated no longer increased with PCA-MnO 2 @OSBC / Cotton significantly increased with the increase of the dosage, so the removal rate of sulfamethoxazole did not show significant difference. This shows that at a dosage of 0.4 g / L, PCA-MnO 2 @OSBC / Cotton has been able to form an efficient synergistic effect with PAA. Further increasing the dosage will not effectively improve the degradation efficiency, but will increase unnecessary costs. Taking into account the removal effect and economy, 0.4 g / L was selected as the additive dosage of the degradation system.

[0178] Example 7

[0179] This example explores the effect of solution pH on the removal capacity of sulfamethoxazole in a ternary system, including:

[0180] Binary system (PCA-MnO 2 @OSBC / Cotton / PAA) PCA-MnO 2The dosage of @OSBC / Cotton was 20 mg, the concentration of sulfamethoxazole was 10 μmol / L, the degradation system was 50 mL of ultrapure water, the concentration of peracetic acid was 400 μmol / L, the pH of the solution was set to 3, 5, 7, 9 and 11, and it was stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken at the set time (0-15min), and the residual and concentration of sulfamethoxazole were determined by HPLC-MS to explore the effect of solution pH on the removal ability of sulfamethoxazole in the ternary system.

[0181] Depend on Figure 7 It can be seen that the removal rates of sulfamethoxazole by the ternary system were 92.1%, 94.6%, 95.1%, 95.0% and 92.4% when the solution pH was set to 3, 5, 7, 9 and 11, respectively. The removal rates showed significant differences due to the changes in solution pH. When the solution pH was 7, the removal rate of sulfamethoxazole by the binary system was as high as 95.1%. The catalytic activity of PCA-MnO2@OSBC / Cotton may reach the best state under neutral conditions. MnO 2 The manganese ions in the 3+ and Mn 4+ Both forms of manganese ions contribute to the catalytic reaction and are relatively stable under neutral conditions. However, in acidic or alkaline environments, ROS may be more likely to undergo side reactions or decompose, resulting in a decrease in its degradation efficiency. In addition, due to the presence of protocatechuol-MnO on the absorbent cotton, 2 The PCA was grafted onto the sludge / biochar composite material, and the system's anti-interference ability to pH was significantly improved, and it could maintain a high removal rate in a wider pH range.

[0182] Example 8

[0183] This example explores the effect of HA concentration on the removal capacity of sulfamethoxazole in the ternary system, including:

[0184] Binary system (PCA-MnO 2 @OSBC / Cotton / PAA) PCA-MnO 2 The dosage of @OSBC / Cotton was 20 mg, the concentration of sulfamethoxazole was 10 μmol / L, the concentration of peracetic acid was 400 μmol / L, the degradation system was 50 mL of ultrapure water, the solution pH was 7.71 (simulating actual aquaculture wastewater), the humic acid (HA) concentrations were set to 0, 1, 5 and 10 mg / L, respectively, and stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken at the set time (0-15 min), and the residual and concentration of sulfamethoxazole were determined by HPLC-MS to explore the effect of HA concentration in the ternary system on the removal ability of sulfamethoxazole.

[0185] Depend on Figure 8 It can be seen that when HA is set to 0, 1, 5 and 10 mg / L, the removal rates of sulfamethoxazole by the binary system are 96.1%, 88.4%, 88.9% and 88.7%, respectively. With the increase of HA concentration, the removal rate of the system shows a downward trend. When the HA concentration is 10 mg / L, the removal rate of sulfamethoxazole is 88.7% after 15 min of reaction, indicating that the increase of HA concentration will inhibit the MnO 2 @OSBC activates the ability of ferrate to degrade sulfamethoxazole. The inhibitory effect of HA may be attributed to the fact that HA molecules can compete with sulfamethoxazole for adsorption sites, reducing the contact opportunities between sulfamethoxazole and the active sites on the catalyst surface. At the same time, HA has the ability to scavenge free radicals and can consume the ROS generated in the system, thereby reducing the chance of ROS reacting with sulfamethoxazole. Despite this, the system still showed good degradation efficiency at high HA concentrations. This is mainly due to the presence of protocatechol-MnO loaded on cotton wool. 2 The excellent performance of the sludge biochar composite material. The three-dimensional porous structure and abundant active sites provided by the composite material enhance the system's ability to adsorb and degrade pollutants. At the same time, the grafted PCA improves the system's anti-interference ability, allowing it to maintain a good degradation efficiency under complex water quality conditions.

[0186] Example 9

[0187] This example explores the effect of coexisting inorganic ions on the system's ability to remove sulfamethoxazole, including:

[0188] Binary system (PCA-MnO 2 @OSBC / Cotton / PAA) PCA-MnO 2 The dosage of @OSBC / Cotton was 20 mg, the concentration of peracetic acid was 400 μmol / L, the concentration of sulfamethoxazole was 10 μmol / L, the degradation system was 50 mL of ultrapure water, the solution pH was 7.71 (simulating actual aquaculture wastewater), and Na 2 CO 3 、NaHCO 3 、NaNO 3 , NaCl and Na 2 SO 4 When the concentration was 0, 1, 5 and 10 mmol / L, the mixture was stirred on a magnetic stirrer at 500 rpm, samples were taken at the set time (0-15 min), and the residual concentration of sulfamethoxazole was determined by HPLC-MS to explore the effect of coexisting inorganic ions on the system's ability to remove sulfamethoxazole.

[0189] Depend on Figure 9-13 It can be seen that Na2 CO 3 、NaHCO 3 、NaNO 3 and NaSO 4 The inhibitory effect on the degradation of sulfamethoxazole by the binary system increased with the increase of its concentration. 2 CO 3 The inhibitory effect was strongest when Na 2 CO 3 When the concentration of Na was 0, 1, 5 and 10 mmol / L, the removal efficiency of sulfamethoxazole by the binary system was 96.1%, 90.5%, 20.0% and 17.8%, respectively. 2 HCO 3 The inhibitory effect is stronger when Na 2 HCO 3 When the concentration of Na was 0, 1, 5 and 10 mmol / L, the removal efficiency of sulfamethoxazole by the binary system was 96.1%, 91.9%, 50.9% and 26.6%, respectively. 2 CO 3 and Na 2 HCO 3 It has strong coordination ability and can be combined with MnO 2 The metal ions on the surface form stable coordination compounds, thereby blocking the active sites and inhibiting their catalytic activity. In addition, carbonate and bicarbonate ions undergo hydrolysis in the solution to generate carbonic acid (H 2 CO 3 ) and carbon dioxide (CO 2 ), thus affecting the catalytic performance of the system. 3 , NaCl and Na 2 SO 4 The inhibitory effect on the degradation of sulfamethoxazole by the ternary system was small. 3 When the concentration of NaCl was 0, 1, 5 and 10 mmol / L, the removal rates of sulfamethoxazole by the binary system were 96.1%, 88.8%, 88.7% and 88.4%, respectively. Nitrate ions have a high mobility in the solution and can compete with the active sites on the catalyst surface for adsorption, reducing the contact opportunities between sulfamethoxazole and the active sites. In addition, nitrate ions may participate in some redox reactions, consume ROS in the system, and thus reduce the degradation efficiency. When the concentration of NaCl was 0, 1, 5 and 10 mmol / L, the removal rates of sulfamethoxazole by the binary system were 96.1%, 88.8%, 92.3% and 91.1%, respectively. Among them, at low concentrations of Cl - Under these conditions, the generation of active oxygen species in the system may be inhibited. - Under these conditions, Cl -May react with PAA to generate additional active chlorine species, such as Cl · and Cl 2 ·− These substances may promote the degradation of sulfamethoxazole, making the degradation rate of the system slightly higher than that of low concentration Cl - Under the conditions. 2 SO 4 When the concentration of MnO2 was 0, 1, 5 and 10 mmol / L, the removal efficiency of sulfamethoxazole by the binary system was 96.1%, 89.2%, 89.1% and 89.1%, respectively. 2 The metal ions on the surface form sulfate precipitation, which covers the catalyst surface and reduces the accessibility of the active sites. In addition, sulfate ions may participate in ion exchange reactions in the solution, changing the ionic strength of the solution, thereby affecting the catalytic performance of the system. Despite the potential interference of various anions, the system still exhibits strong resistance to anion interference. Protocatechol-MnO supported on cotton wool 2 The sludge / biochar composite material provides a three-dimensional porous structure, which not only increases the specific surface area but also enhances the adsorption capacity of pollutants. This structure helps to maintain efficient degradation performance under complex water conditions. 2 The synergistic effect between them protects the active sites to a certain extent, reduces the direct contact between anions and active sites, and thus reduces the inhibitory effect. The types of ROS generated in the system are diverse. Even if some ROS are consumed or inhibited by anions, other types of ROS can continue to participate in the degradation reaction. With its unique structural design and multi-component synergy, the system can still maintain a good degradation efficiency in the face of interference from anions of different concentrations, showing strong anti-interference ability. This makes the system have significant advantages in practical applications, especially in the treatment of aquaculture wastewater with complex components.

[0190] Example 10

[0191] This example determines the PCA-MnO 2 @OSBC / Cotton’s regeneration and degradation capabilities include:

[0192] Binary system (PCA-MnO 2 @OSBC / Cotton / PAA) PCA-MnO 2The dosage of @OSBC / Cotton was 20 mg, the concentration of peracetic acid was 400 μmol / L, the concentration of sulfamethoxazole was 10 μmol / L, the degradation system was 50 mL of ultrapure water, the solution pH was 7.71 (simulating actual aquaculture wastewater), and the reaction was stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken when the reaction was balanced (15 min), and the residual concentration of sulfamethoxazole was determined by high performance liquid chromatography-mass spectrometry. 2 @OSBC / Cotton was separated by filtration and washed with ultrapure water for 5-6 times. 2 @OSBC / Cotton was placed in a freeze dryer and then subjected to degradation experiments again. This was repeated 5 times to determine the MnO 2 @OSBC’s regeneration and degradation capabilities.

[0193] Depend on Fig.14 It can be seen that PCA-MnO 2 @OSBC / Cotton has good ability to sustainably degrade sulfamethoxazole in the binary system. 2 @OSBC / Cotton, the removal efficiency of sulfamethoxazole by the binary system was 96.1%, 93.9%, 90.0%, 90.8% and 82.8% respectively from the first to the fifth use. After five cycles, the removal efficiency of sulfamethoxazole by the binary system could still reach 82.8%, indicating that PCA-MnO 2 @OSBC / Cotton has strong regeneration and degradation ability. The reduction in removal rate may be due to multiple reactions and cleaning processes. 2 The physical structure of @OSBC / Cotton may change, such as the collapse of the pore structure or the change of the surface morphology, resulting in a decrease in catalytic activity. 2 @The active substances on the surface of OSBC / Cotton may be gradually consumed, resulting in a decrease in its catalytic efficiency. Especially after multiple cycles of use, the regeneration of the active substances may not keep up with the rate of consumption, which may affect its adsorption capacity and catalytic activity on the substrate. Among them, the chemical properties of cotton wool are stable and it is not easy to react with other components in the composite material. This helps to maintain the stability of the composite material and extend its service life.

[0194] Embodiment 11

[0195] This example explores the ability of the system to remove sulfamethoxazole when ultrapure water is replaced with filtered Yangtze River water, Thompson Lake water, livestock breeding wastewater, outlet sewage, tap water and drinking water, including:

[0196] Binary system (PCA-MnO 2 @OSBC / Cotton / PAA) PCA-MnO 2 The dosage of @OSBC / Cotton was 20 mg, the concentration of peracetic acid was 400 μmol / L, the concentration of sulfamethoxazole was 10 μmol / L, and the ultrapure water was replaced with filtered Yangtze River water, Thompson Lake water, livestock breeding wastewater, outlet sewage, tap water and drinking water. The total volume of the degradation system was 50 mL, and it was stirred on a magnetic stirrer at a speed of 500 rpm. Samples were taken when the reaction was in equilibrium (15 min), and the residual concentration of sulfamethoxazole was determined by high performance liquid chromatography-mass spectrometry.

[0197] Depend on Fig.15 It can be seen that the binary system has a strong degradation ability for sulfamethoxazole in various actual water bodies. The degradation rates of sulfamethoxazole in filtered Yangtze River water, Thompson Lake water, livestock breeding wastewater, outlet sewage, tap water and drinking water are 86.5%, 90.0%, 89.3%, 84.3%, 85.3% and 89.9%, respectively. The binary system shows significant advantages in degrading sulfamethoxazole in various water bodies. Taking into account the various interfering substances that may exist in actual water bodies, such as organic matter, nutrients, suspended matter, antibiotic residues, and disinfection by-products, the binary system can still resist the interference of these factors and continue to maintain its efficient catalytic activity and stable catalytic effect. The addition of PCA effectively improves the anti-interference ability of the binary system. PCA, as a phenolic acid substance with antioxidant properties, can remove free radicals in the system and reduce oxidative stress, thereby protecting the catalyst from oxidative damage and maintaining its activity. It also has an inhibitory effect on a variety of bacteria. This antibacterial property may help reduce the biodegradation of the catalyst by microorganisms in water, thereby improving the stability and degradation efficiency of the catalyst. In addition, the system is easy to operate and does not require cumbersome pre-treatment steps. It can be directly applied to actual water degradation treatment, reducing operating costs and time costs, and has more advantages in terms of economy and practicality. At the same time, the materials and reagents used in the system are relatively environmentally friendly and will not cause secondary pollution to the water environment. It is in line with the concept of green chemistry and has more environmental advantages than traditional treatment methods that may introduce harmful substances. In summary, this binary system has significant advantages over other methods in degrading sulfamethoxazole in aquaculture wastewater due to its high efficiency, stability, economy and environmental friendliness, and has broad practical application prospects.

[0198] Example 12

[0199] This example explores the ability of the system to remove various sulfonamide antibiotics when different types of sulfonamide antibiotics are added, including:

[0200] Binary system (PCA-MnO2 @OSBC / Cotton / PAA) PCA-MnO 2 The dosage of @OSBC / Cotton was 20 mg, the concentration of peracetic acid was 400 μmol / L, the degradation system was 50 mL of ultrapure water, the solution pH was 7.71 (simulating actual aquaculture wastewater), the concentrations of sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine and sulfathiazole were 10 μmol / L, and the mixture was stirred on a magnetic stirrer at 500 rpm. Samples were taken at the set time (0-15 min), and the residual concentration of sulfamethoxazole was determined by HPLC-MS to explore the ability of the system to remove sulfonamide antibiotics.

[0201] Depend on Fig.16 It can be seen that PCA-MnO 2 The degradation rates of @OSBC / Cotton / PAA system for sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine and sulfathiazole were 96.%, 94.6%, 91.4%, 93.9% and 90.3%, respectively. This binary system showed excellent degradation ability for various sulfonamide antibiotics, which fully proved that it has great application potential and prospects in the field of antibiotic wastewater treatment. Fig.17 It can be seen that the binary system not only has a high degradation efficiency, but also has an extremely high mineralization rate, which can quickly mineralize sulfonamide antibiotics into harmless or low-toxic substances. This efficient degradation and mineralization ability greatly reduces the potential risks of antibiotics to the environment and ecosystem, and further highlights its environmental friendliness in wastewater treatment. Therefore, it can be said that the binary system is very effective for most sulfonamide antibiotics, and its high mineralization rate also ensures the safety of the treated water quality, providing an efficient and environmentally friendly solution for the treatment of wastewater containing a variety of sulfonamide antibiotics.

[0202] Example 13

[0203] This example explores the ability of a fixed bed system to remove sulfonamide antibiotics from aquaculture wastewater, including:

[0204] In the binary system (PCA-MnO 2 @OSBC / Cotton / PAA) based on a fixed bed system, such as Fig.18 As shown, the system includes a filling column 3, a peristaltic pump and a solution introduction device 1, wherein the filling column is filled with absorbent cotton loaded with protocatechol-MnO 2 / sludge biochar composite material; the solution introduction device can contain peracetic acid solution, the solution introduction device is connected to the input end of the filling column through a peristaltic pump 2, the premixed solution introduction device can input the peracetic acid solution into the filling column, and the aquaculture wastewater containing sulfamethoxazole 5 is also connected to the input end of the filling column through another peristaltic pump 4, and the peristaltic pump inputs the aquaculture wastewater containing sulfamethoxazole into the filling column;

[0205] Wherein, the concentration of the peracetic acid is 100-800 μmol / L;

[0206] The peristaltic pump flow rate is 0.1-60 mL / min.

[0207] Preferably, in a fixed bed system, the peristaltic pump flow rate is 10 mL / min, the packed column length is 30 cm, the packed column radius is 2 cm, and the PCA-MnO 2 @OSBC / Cotton filler has a mass of 400 mg. The filler is placed in a filling column. The filtered aquaculture wastewater containing sulfonamide antibiotics and a solution of peracetic acid are introduced into the filling column at a flow rate ratio of 1:1 through a peristaltic pump. The liquid flowing out of the filling column is the aquaculture wastewater after the sulfonamide antibiotics are removed. Samples are taken at the set time (0-1440 min), and the residual concentration of sulfamethoxazole is determined by high performance liquid chromatography-mass spectrometry to explore the ability of the fixed bed system to remove sulfonamide antibiotics.

[0208] Fig.18 The PCA-MnO 2 The fluidized bed system designed by @OSBC / Cotton / PAA binary system is designed to efficiently remove sulfonamide antibiotics from sludge. The core of the system is a packed column with a length of 30 cm and a radius of 2 cm, which is filled with PCA-MnO 2 @OSBC / Cotton filler. The filtered wastewater containing sulfonamide antibiotics and peracetic acid solution were transported to the packed column at a flow rate of 10 mL / min by a peristaltic pump at a flow rate ratio of 1:1 to achieve continuous removal of sulfamethoxazole in aquaculture wastewater. Fig.19 It can be seen that the fixed bed system has a strong degradation ability for sulfamethoxazole in aquaculture wastewater. Within the degradation time of 0 to 1440 min, the system can effectively reduce the sulfamethoxazole content in aquaculture wastewater containing an initial concentration of 10 μmol / L sulfamethoxazole. The system showed a rapid response to sulfamethoxazole in the initial stage, indicating that PCA-MnO 2The @OSBC / Cotton / PAA system has immediate and efficient catalytic activity. During the entire 1440 min experimental period, the fixed bed system maintained a stable degradation efficiency, indicating that the system has good durability and stability and is suitable for long-term operation. The experimental results show that the system can achieve a high removal rate of sulfamethoxazole, which is attributed to the PCA-MnO 2 @OSBC / Cotton's strong oxidizing ability and the role of PAA in the system. Even in a complex aquaculture wastewater environment, the system can maintain a high degradation efficiency and show good anti-interference performance, which is particularly important for actual wastewater treatment. By delivering premixed solutions through a peristaltic pump, the system achieves continuous flow reaction, is easy to operate and easy to control, and is suitable for industrial applications. In summary, Fig.18 The fixed bed system shown in the paper exhibits excellent performance in the degradation of sulfamethoxazole. It not only has high degradation efficiency but also is easy to operate and environmentally friendly, and has good application prospects.

[0209] There are some similar products in the prior art, but the present invention is based on PCA-MnO 2 @The fluidized bed system designed with the binary system of OSBC / Cotton / PAA has significant advantages, mainly in terms of economy, indirect efficiency, catalyst recovery and packing characteristics. The following is a comparison between the present invention and the existing common technology:

[0210] Table 2 Comparison of advantages of the present invention and existing common technologies

[0211]

[0212] The fluidized bed system of the present invention is superior to the prior art in multiple key indicators and has significant advantages. These advantages not only improve the processing efficiency and economy of the system, but also enhance its feasibility and sustainability in practical applications, making it more in line with the needs of industrial applications. 2 @The detailed advantages of the fluidized bed system designed with the OSBC / Cotton / PAA binary system are as follows:

[0213] Advantages of catalyst recovery: In the prior art, powdered catalysts are directly added to water bodies, which makes it difficult to effectively recover them from dynamic water flows, resulting in resource waste and potential secondary pollution. However, the present invention fixes the catalyst on a three-dimensional porous cellulose-based carrier. The catalyst is not directly added to the treated water body, but is fixed by the physical structure and chemical bonding of the carrier. It can be efficiently recovered by simple physical methods (such as filtration and centrifugation), reducing resource waste and environmental pollution.

[0214] Treatment efficiency advantage: the existing immobilization technology (such as silica gel embedding) cannot meet the large flow demand of aquaculture wastewater treatment due to the pore size blockage of the carrier and the decrease of flux. 2 / Sludge biochar was used to construct a three-dimensional porous cellulose-based carrier. Its unique structure and modification treatment provided a large specific surface area and good permeability, reduced the risk of pore blockage, maintained high flux and treatment efficiency, and experiments showed that it maintained efficient degradation of sulfamethoxazole during the 1440 min experimental period.

[0215] Economic advantage: The existing technology requires frequent replenishment of catalysts, which is costly. The catalyst of the present invention is fixed on a carrier and can be reused, reducing the replacement frequency and use cost. At the same time, the system is easy to operate and has low energy consumption, which further reduces operating costs and improves economic efficiency.

[0216] Anti-pollution ability advantage: Using absorbent cotton as a three-dimensional porous cellulose-based carrier and loading catalyst has good anti-pollution performance and can maintain a stable treatment effect in a complex wastewater environment. Its porous structure and chemical modification can absorb and intercept some pollutants, reduce the impact on catalyst activity, and maintain long-term stable operation of the system.

[0217] Advantages of operational complexity: Some existing technologies are complex to operate and require professionals and equipment. The fluidized bed system of the present invention realizes automatic control through peristaltic pumps and other equipment, is easy to operate and maintain, has low requirements on operators, reduces labor costs, and improves the feasibility of practical application.

[0218] Startup time advantage: The system of the present invention is reasonably designed, and the catalyst fixation and fluidized bed structure are conducive to rapid startup, shortening the preparation time and improving the operating efficiency, while some existing systems have a long startup time.

[0219] Maintenance frequency advantage: The system structure of the present invention is stable, the carrier and catalyst are wear-resistant and pollution-resistant, maintenance is simple, and the frequency of component replacement is low, which reduces downtime and maintenance costs and improves operation continuity and reliability.

[0220] Energy consumption advantage: The main energy-consuming equipment of the present invention is a peristaltic pump, which has low power and only needs to provide power for wastewater diuresis during operation, with low energy consumption and low operating cost. Some existing technologies may involve complex equipment and high temperature and high pressure conditions, with high energy consumption.

[0221] Adaptability advantage: Using defatted cotton as a three-dimensional porous cellulose-based carrier and loading the catalyst has good adaptability and can treat wastewater of different types and concentrations. By adjusting the carrier and catalyst formula and system parameters, the treatment effect can be further optimized. The present invention maintains high-efficiency degradation performance in complex aquaculture wastewater and embodies good adaptability.

[0222] Although the embodiments of the present invention are disclosed for illustrative purposes, those skilled in the art will appreciate that various substitutions, changes and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the scope of the present invention is not limited to the contents disclosed in the embodiments.

Claims

1. A method for preparing a composite material for sulfonamide antibiotic treatment, characterized in that: The steps include: S1, preparing sludge biochar SBC; S2, immersing the SBC in acid, and performing microwave-assisted acid treatment in a microwave chemical reactor to obtain functionalized sludge biochar OSBC; S3, wet ball milling the functionalized sludge biochar and the pore regulator in anhydrous acetone, mixing the ball milling product with the manganese source, the crystal plane directing agent, the dispersant and the solvent, and obtaining the ultra-dense polycrystalline MnO2-coated porous functionalized sludge biochar MnO2@OSBC through one-pot hydrothermal synthesis; S4, reacting protocatechol PCA with ethylenediamine EDA under the catalysis of carbodiimide / succinimide (EDC / NHS), purifying by centrifugation precipitation with n-hexane, washing with anhydrous acetone and vacuum drying to obtain aminated PCA (PCA-NH2); S5, reacting MnO2@OSBC with PCA-NH2 in a carbodiimide / succinimide (EDC / NHS) system, centrifugally washing, and vacuum drying to obtain PCA-MnO2@OSBC; S6. Cut the cotton wool and clean it ultrasonically with deionized water, dry it for later use, disperse PCA-MnO2@OSBC in polyvinyl alcohol (PVA) solution and ultrapure water to obtain a suspension of PCA-MnO2@OSBC-PVA solution and a PCA-MnO2@OSBC water-based suspension, respectively, soak the cotton wool in the suspension of PCA-MnO2@OSBC-PVA solution, add glutaraldehyde for cross-linking and curing, immerse the cross-linked cotton wool in the PCA-MnO2@OSBC water-based suspension, freeze-dry and heat-treat it under an inert gas atmosphere, and finally obtain the cotton wool loaded with protocatechuol-MnO2 / sludge biochar composite material PCA-MnO2@OSBC / Cotton for sulfonamide antibiotic aquaculture wastewater treatment.

2. The preparation method according to claim 1, characterized in that: In S1, the sludge biochar is prepared by pyrolyzing the sludge; Before the sludge is subjected to pyrolysis treatment, the process also includes: using solid-liquid separation equipment to collect sludge from the sludge treatment system of the sewage treatment plant, washing the sludge with ultrapure water and freeze-drying the sludge until it reaches a constant weight state, removing soluble impurities and excess water therein, and obtaining pre-treated sludge; wherein the sludge has an organic matter content of 40-90%, a freeze-drying temperature of -60-10°C, and a freeze-drying vacuum of 10-100 Pa; During the pyrolysis treatment of sludge: the heating rate is 5-20℃ / min; the pyrolysis is continued at 400-800℃ for 60-180 min; the pyrolysis atmosphere is inert gas; the gas flow rate is 0.05-0.4 L / min; After the residual sludge is pyrolyzed, the process further includes: acid washing the pyrolysis product to remove the soluble ash therein, then washing it with ethanol and water alternately until the pH value of the filtrate is neutral, freeze drying it to constant weight, grinding and sieving it to obtain sludge biochar; wherein the acid used in the acid washing process is an inorganic acid; the freeze drying temperature is -60-10°C; the freeze drying vacuum degree is 10-100 Pa; and after grinding, passing through a 50-300 mesh sieve; Alternatively, in S2, the acid is dilute nitric acid; the ratio of SBC to dilute nitric acid g:mL is 1-20:200; the mass concentration of dilute nitric acid is 20%-68%; the microwave treatment time is 0.1-2 h, and the microwave power is 100 W-600 W; Alternatively, the functionalized sewage sludge biochar OSBC in S2 is also treated as follows: The filtrate was rinsed alternately with ethanol and water until the pH of the filtrate was neutral, and then freeze-dried to constant weight and ground and sieved to obtain sludge biochar; wherein the freeze-drying temperature was -60-10°C; the freeze-drying vacuum was 10-100 Pa; and the sludge was ground and sieved through a 50-300 mesh sieve.

3. The preparation method according to claim 1, characterized in that: In S3, the functionalized sludge biochar OSBC and solid sodium chloride particles are placed in a zirconia ball mill, anhydrous acetone and zirconia grinding balls are added for wet ball milling, and the solvent is subsequently recovered by freeze drying; the ball milled product is then placed in a solution containing permanganate, sodium citrate, and polyethylene glycol for ultrasonic mixing, and then transferred to a reactor for hydrothermal synthesis under optimized hydrothermal synthesis conditions, and the solid is filtered to obtain the solid, which is washed with ultrapure water until the filtrate is colorless, dried, ground, and sieved to obtain ultra-dense polycrystalline MnO2-coated porous functionalized sludge biochar MnO2@OSBC; Among them, solid sodium chloride is used as a soluble multi-level pore template agent for hydrothermal synthesis, potassium permanganate is used as a manganese source for the hydrothermal synthesis system, sodium citrate is used as a crystal plane director for the hydrothermal synthesis system, and polyethylene glycol PEG10000 is used as a dispersant for the hydrothermal synthesis system; The mass ratio of solid sodium chloride to sludge biochar is 0.1-0.3:1; the mass ratio of acetone to sludge biochar is 3-5:1; the mass ratio of zirconium oxide grinding balls to sludge biochar is 5-50:1; the ball milling speed is 100-500 rpm; the ball milling time is 30-90 min; the freeze-drying temperature is -60-10°C; the freeze-drying vacuum is 10-100 Pa; In step S3, the mass ratio of potassium permanganate to sludge biochar is 0.57-5.66:1; the molar concentration ratio of potassium permanganate to sodium citrate is 1-6:1; water is used in the one-pot hydrothermal synthesis, and the dosage ratio of sludge biochar to water is 1:10-100 in g:mL; the mass ratio of dispersant to sludge biochar is 0.1-10:1; Alternatively, the mixture is uniformly mixed by ultrasound in S3; Alternatively, the mass ratio of the dispersant to the sludge biochar is 0.1-10:1; the ultrasonic time is 10-30 min; the ultrasonic temperature is 20-80°C; the ultrasonic power is 100-300 W; Alternatively, the temperature of the hydrothermal reaction in S3 is 110-200 °C, and the time of the hydrothermal reaction is 60 min-360 min; Alternatively, the product after the one-pot hydrothermal synthesis in S3 is further treated as follows: The product after one-pot hydrothermal synthesis is filtered, washed with water until the filtrate is colorless, freeze-dried to constant weight, ground and sieved to obtain ultra-dense polycrystalline MnO2-coated functionalized sludge biochar; wherein the freeze-drying temperature is -60-10°C; the freeze-drying vacuum degree is 10-100Pa, and the product is ground and sieved through a 50-200 mesh sieve.

4. The preparation method according to claim 1, characterized in that: In S4, protocatechuol PCA and ethylenediamine EDA are dissolved in phosphate buffer, and EDC / NHS is added to react in the dark. After the reaction, the mixture is precipitated by n-hexane and centrifuged. The precipitate is collected and washed with anhydrous acetone, and then dried in vacuum to obtain aminated PCA, i.e., PCA-NH2. In the process of synthesizing aminated PCA: the pH of the phosphate buffer solution is 3-9; the volume of the phosphate buffer solution added to each 1.00 g of protocatechol is 60-200 mL; the molar ratio of PCA to EDA is 1:1-5; the molar ratio of EDC:NHS:PCA is 1-3:1-3:1; the reaction time is 4-24 h; the shaking rate is 100-200 rpm; the reaction conditions are room temperature and protected from light throughout the process; Alternatively, the volume ratio of n-hexane to reaction liquid is 2-5:1; the centrifugation condition is 4000-8000 rpm; the centrifugation time is 10-30 min; the freeze-drying temperature is -60-10°C; the freeze-drying vacuum degree is 10-100 Pa; Alternatively, in S5, PCA-MnO2@OSBC is subjected to a pre-reaction treatment, including: adding MnO2@OSBC and amino PCA to ultrapure water and thoroughly mixing them by ultrasonication; wherein the ultrasonication time is 10-30 min; the ultrasonication temperature is 20-80°C; the ultrasonication power is 100-300 W; and the volume of ultrapure water added to each 1.00 g of MnO2@OSBC is 60-200 mL; Alternatively, the mass ratio of EDC to PCA-MnO2@OSBC in S5 is 1-3:1; the molar ratio of EDC to NHS is 1:1; the shaking rate is 100-200 rpm; the concentration of PCA-NH2 solution is 1-5 mg / mL; the reaction time is 12-48 h; the reaction conditions are room temperature and protected from light throughout the process; After the reaction in the EDC / NHS system, the reaction solution was precipitated and centrifuged with anhydrous ethanol, the precipitate was collected and washed with anhydrous ethanol, and then vacuum dried to obtain PCA-MnO2@OSBC; wherein the volume ratio of anhydrous ethanol: reaction solution was 2-5:1; the centrifugation conditions were 4000-8000 rpm; the centrifugation time was 10-30 min; the freeze-drying temperature was -60-10°C; and the freeze-drying vacuum was 10-100 Pa.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In S6, the size of the cotton wool after cutting is 0.5 cm × 0.5 cm to 2 cm × 2 cm; the ultrasonic temperature is 20-80°C; the ultrasonic power is 100-300 W; the ultrasonic time is 10-30 min; the drying temperature is 50-80°C, the drying temperature is 60°C; the drying time is 6-12 h; Alternatively, the mass concentration of polyvinyl alcohol (PVA) solution is 3-7%; the immersion time is 0.5-2 h; the added volume concentration of glutaraldehyde is 1-3%; the curing temperature is 50-70°C; the curing time is 1-3 h; the concentration of PCA-MnO2@OSBC suspension is 0.5-2 mg / mL; the freeze-drying temperature is -60-10°C, and the freeze-drying vacuum is 10-100 Pa; the heat treatment temperature is 100-150°C, and the heat treatment time is 0.5-2 h; and the inert gas is N2.

6. A composite material for sulfonamide antibiotic treatment obtained by the preparation method according to any one of claims 1 to 5.

7. Use of the composite material for treating sulfonamide antibiotics as claimed in claim 6 in efficiently activating peracetic acid to degrade sulfonamide antibiotics in water.

8. A method for using the composite material for sulfonamide antibiotic treatment as claimed in claim 6, characterized in that: The steps include: The cotton wool loaded protocatechuol-MnO2 / sludge biochar composite material is cut and added into an aqueous solution containing peracetic acid and sulfonamide antibiotics. After the degradation process is completed, it is filtered to obtain a solution after the sulfonamide antibiotics are removed.

9. The method according to claim 8, characterized in that: The sulfonamide antibiotics include at least one of sulfamethoxazole, sulfadiazine, sulfacetamide, sulfadoxine, and sulfathiazole; Alternatively, the concentration of sulfonamide antibiotics is 1-20 μmol / L; the concentration of peracetic acid is 100-800 μmol / L; Alternatively, the dosage of the cotton wool loaded protocatechuol-MnO2 / sludge biochar composite material is 0.1-0.8 g / L; the system pH is 1-14.

10. A fixed bed system of a composite material for treating sulfonamide antibiotics according to claim 6, characterized in that: The system comprises a filling column, a peristaltic pump and a premixed solution introduction device, wherein the filling column is filled with absorbent cotton loaded with protocatechuol-MnO2 / sludge biochar composite material; The premix solution introduction device can contain the PAA solution, and the premix solution introduction device is connected to the input end of the filling column through a peristaltic pump. The premix solution introduction device can input the PAA solution into the filling column. The aquaculture wastewater containing sulfamethoxazole is also connected to the input end of the filling column through another peristaltic pump, and the peristaltic pump inputs the aquaculture wastewater containing sulfamethoxazole into the filling column.

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