Preparation method of Mn self-assembled biochar

Abstract

The invention provides a preparation method of Mn self-assembled biochar, and belongs to the technical field of biochar. Typical agricultural / urban solid wastes are taken as raw materials to be subjected to high-temperature pyrolysis in a nitrogen atmosphere to prepare biochar, then the biochar is used for adsorbing and simulating Mn (II) in aquaculture wastewater, and the Mn (II) adsorption capacity is evaluated. And carrying out freeze-drying treatment on the Mn (II)-adsorbed saturated biochar material, and carrying out pyrolysis again to prepare the spherical Mn self-assembled biochar. The spherical Mn self-assembled biochar prepared by the method can efficiently activate persulfate generated by electrochemistry to degrade antibiotics in water, and the removal rate of various antibiotics can reach 80% or above when the reaction is carried out for 60 min. According to the method, harmless treatment and resource utilization of the rice straw can be achieved, and meanwhile efficient removal of Mn (II) and antibiotics in the breeding wastewater is achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of biochar, and in particular relates to a method for preparing Mn self-assembled biochar. Background Art

[0002] In recent years, persulfate-based advanced oxidation technology has attracted special attention from researchers in the degradation of new pollutants, mainly because of its diverse activation methods (carbon-based materials, ultrasound, ultraviolet and metal-organic frameworks, etc.) and the ability to produce a variety of active oxygen groups (free radicals and non-free radicals). Among them, carbon-based materials-biochar are considered to be a promising catalytic material due to its advantages such as wide raw material sources, low cost and good biocompatibility, but the practical application of biochar is still limited by its weak catalytic ability. Studies have shown that doping with transition metals (such as Mn, Fe, Co and Cu, etc.) and non-metals (such as N, P, B and S, etc.) can significantly improve the activation ability of biochar for persulfate. Among them, transition metal-doped biochar has high metal utilization, unsaturated coordination environment, stable structure and strong electron transfer ability, and is considered to be an efficient persulfate heterogeneous catalyst. However, the preparation of existing transition metal-doped biochar for persulfate activation is achieved by introducing chemical reagents containing transition metals into biochar exogenously, and its practical application is still limited by its high production cost, complex doping process and possible metal dissolution risk.

[0003] Transition metal elements (such as Mn) are important components of enzymes, hormones and vitamins in livestock and poultry. They constitute organic compounds with certain special functions in animal soft tissues and are often used as feed additives to promote the growth, development and reproduction of livestock and poultry. After being ingested by animals, except for a small amount that can be metabolized and absorbed, 78%-95% will be excreted through feces and urine and enter the aquaculture wastewater, causing water pollution. Studies have shown that biochar adsorption is considered to be a low-cost, efficient and easy-to-operate technology for removing transition metals from wastewater (such as aquaculture wastewater, etc.), but the harmless treatment of biochar after adsorbing transition metals is still an urgent problem to be solved.

[0004] In addition, it is worth noting that the persulfate in the current persulfate-based advanced oxidation technology is mostly derived from exogenously added persulfate or peroxydisulfate. The addition of exogenous persulfate not only increases operating costs, but may also cause secondary pollution to water bodies, which to some extent limits the application and development of this technology. Introducing electrochemical technology into sulfate-containing wastewater can convert sulfate (SO4 2- ) generates persulfate (E-PS) in situ at the anode (2SO4 2- → S2O8 2- +2e -), which provides a feasible method for achieving the non-exogenous addition of persulfate. At the same time, the introduction of electrochemical technology can continuously provide electrons to the surface of the biochar after the reaction, so that their consumed carboxyl, hydroxyl and reduced transition metal ions are regenerated, achieving efficient and sustainable degradation of target pollutants. Summary of the invention

[0005] Based on the above shortcomings of the prior art, the technical problem solved by the present invention is to screen a biochar that can efficiently adsorb and remove Mn(II) in aquaculture wastewater, and prepare the biochar saturated with Mn(II) adsorption as a catalyst that can efficiently activate electrochemically generated persulfate to degrade antibiotics. This treatment technology can not only realize the resource utilization of waste, but also realize the efficient removal of antibiotics in water, without the need for exogenous addition of chemical modifiers and oxidants in the process.

[0006] In order to solve the above technical problems, the present invention provides a preparation method of spherical Mn self-assembled biochar that can efficiently activate electrochemically generated persulfate to degrade antibiotics, comprising the following steps: The collected or purchased agricultural / urban solid waste (rice straw, corn straw, soybean straw, wheat straw, bagasse and municipal sludge) was washed with ultrapure water and dried to constant weight, then placed in a tube furnace for pyrolysis under anaerobic conditions, ground and sieved to produce rice straw biochar (RBC), corn straw biochar (CBC), soybean straw biochar (SBBC), wheat straw biochar (WBC), bagasse biochar (BBC) and sludge biochar (SBC); (2) Preparation of spherical Mn self-assembled biochar: The biochar obtained in step (1) was used to adsorb Mn(II) in simulated aquaculture wastewater. The test results showed that rice straw biochar (RBC) had the strongest adsorption capacity for Mn(II). The rice straw biochar (RBC) saturated with Mn(II) was filtered and freeze-dried in a freeze dryer, and then placed in a tubular furnace for pyrolysis under anaerobic conditions, ground and sieved to obtain spherical Mn self-assembled rice straw biochar (Mn@RBC).

[0007] As a preferred embodiment of the above technical solution, the preparation of a spherical Mn self-assembled biochar (Mn@RBC) that can efficiently activate electrochemically generated persulfate-degradable antibiotics provided by the present invention further includes some or all of the following technical features: As an improvement of the above technical solution, in the step (1), the drying temperature is 50-105°C; the pyrolysis conditions are a nitrogen flow rate of 0.1-0.5 L / min, a heating rate of 5-20°C / min, a pyrolysis temperature of 300-900°C, and a pyrolysis time of 30-480 min; and after grinding, the granules are sieved through a 60-200 mesh sieve.

[0008] As an improvement of the above technical solution, in the step (2), the amount of biochar added is 0.01-0.05 g, the concentration of Mn(II) is 10-200 mg / L, and the volume of aquaculture wastewater is 0.1-0.5 L; the freeze-drying temperature is -45°C to -35°C, and the vacuum degree is 20-50 Pa; the flow rate of nitrogen during pyrolysis is 0.1-0.5 L / min, the heating rate is 5-20°C / min, the pyrolysis temperature is 300-900°C, and the pyrolysis time is 30-480 min; after grinding, the sieve is passed through a 60-200 mesh sieve.

[0009] A spherical Mn self-assembled biochar (Mn@RBC) that can efficiently activate electrochemically generated persulfate to degrade antibiotics. The spherical Mn self-assembled biochar (Mn@RBC) is prepared by any of the above methods.

[0010] A spherical Mn self-assembled biochar (Mn@RBC) that can efficiently activate electrochemically generated persulfate to degrade antibiotics comprises the following steps: using the prepared Mn self-assembled rice straw biochar (Mn@RBC) as a catalyst to activate electrochemically generated persulfate (E-PS) to degrade antibiotics, and filtering after the oxidation reaction is completed to obtain a solution after the antibiotics are degraded.

[0011] As a preferred embodiment of the above technical solution, the present invention provides a spherical Mn self-assembled biochar (Mn@RBC) that can efficiently activate electrochemically generated persulfate-degradable antibiotics, further comprising some or all of the following technical features: As an improvement of the above technical solution, the concentration of sulfamethoxazole in the antibiotic solution is 2.5-10 mg / L and the pH is 3-11; the dosage of Mn self-assembled rice straw biochar (Mn@RBC) is 0.0025-0.02 g; the concentration of Na2SO4 is 0.1-5 mM; and the voltage is 10-30 V.

[0012] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: it provides a preparation method of spherical Mn self-assembled biochar (Mn@RBC) using persulfate that can efficiently activate electrochemical generation, which can not only efficiently eliminate Mn (II) and antibiotics in aquaculture wastewater, but also realize the resource utilization of rice straw.

[0013] (1) The spherical Mn self-assembled biochar (Mn@RBC) prepared in the present invention can efficiently activate electrochemically generated persulfate, and the degradation rate of various antibiotics can reach more than 80% within 60 min.

[0014] (2) Compared with other technologies (such as adsorption and microbial degradation), the spherical Mn self-assembled biochar (Mn@RBC) prepared in the present invention can not only efficiently activate electrochemically generated persulfate to degrade antibiotics, but also achieve the removal of Mn(II) in aquaculture wastewater and the resource utilization of agricultural waste. This technology has the advantages of simple operation process, low cost and the prospect of large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 Comparison of the adsorption capacity of different biochars on Mn(Ⅱ) in simulated aquaculture wastewater; Figure 2 is the fitting curve of the adsorption isotherm of RBC to Mn(Ⅱ); Figure 3 Surface morphology of RBC and Mn@RBC; Figure 4 The removal performance of 5 mg / L sulfamethoxazole by different reaction systems (RBC, Mn@RBC, E, E / Na2SO4, E / RBC, E / Mn@RBC, RBC / Na2SO4, Mn@RBC / Na2SO4, E / Na2SO4 / RBC and E / Na2SO4 / Mn@RBC) within 0-60 min. Figure 5 The effect of voltage (10-30 V) on the removal capacity of E / Na2SO4 / Mn@RBC system for 10 mg / L sulfamethoxazole in 0-60 min; Figure 6 The effect of Na2SO4 concentration (0.1-5 mM) on the removal capacity of E / Na2SO4 / Mn@RBC system for 5 mg / L sulfamethoxazole in 0-60 min; Figure 7 The effect of Mn@RBC dosage (0.0025-0.02 g) on ​​the removal capacity of E / Na2SO4 / Mn@RBC system for 5 mg / L sulfamethoxazole in 0-60 min; Figure 8 The effect of pH (3-11) on the removal capacity of E / Na2SO4 / Mn@RBC system for 5 mg / L sulfamethoxazole in 0-60 min; Fig. 9 is the removal capacity of E / Na2SO4 / Mn@RBC system for sulfamethoxazole with a concentration of 5 mg / L in different actual water bodies; Fig.10 The sustainable removal capacity of E / Na2SO4 / Mn@RBC system for sulfamethoxazole with a concentration of 5 mg / L; Fig.11 The effect of the number of Mn@RBC cycles on the dissolution concentration of Mn ions; Fig.12 The removal capacity of E / Na2SO4 / Mn@RBC system for different antibiotics with a concentration of 5 mg / L. DETAILED DESCRIPTION

[0016] In order to further illustrate the present invention, the technical solutions provided by the present invention are described in detail below in conjunction with embodiments, but they should not be construed as limiting the protection scope of the present invention. Example 1

[0017] The washed rice straw, corn straw, soybean straw, wheat straw, bagasse, tobacco stem and municipal sludge were placed in a 60 ℃ oven and dried to constant weight, then transferred to a high-temperature tube furnace (nitrogen flow rate of 0.1 L / min, heating rate of 10 ℃ / min) for pyrolysis at 600 ℃ for 120 min, and ground through a 100-mesh sieve to obtain rice straw biochar (RBC), corn straw biochar (CBC), soybean straw biochar (SBBC), wheat straw biochar (WBC), bagasse biochar (BBC), tobacco stem biochar (TBC) and sludge biochar (SBC). A mass of 0.02 g of different biochars was placed in a simulated aquaculture wastewater containing Mn(Ⅱ) with a concentration of 40 mg / L and a volume of 0.2 L. Samples were taken and filtered at t=720 min, and the residual Mn(Ⅱ) concentration was determined by atomic absorption spectrophotometer to calculate and compare the adsorption capacity of different biochars for Mn(Ⅱ).

[0018] Depend on Figure 1 It can be seen that the adsorption capacity of different biochars for Mn(Ⅱ) is as follows: RBC>WBC>TBC>BBC>CBC>SBBC>SBC. The adsorption capacity of RBC for Mn(Ⅱ) is significantly higher than that of other biochars, which are 5.12, 4.58, 2.14, 1.88, 1.75 and 1.20 times that of SBC, SBBC, CBC, BBC, TBC and WBC respectively. Therefore, RBC was selected for the adsorption and removal of Mn(Ⅱ) in aquaculture wastewater. Example 2

[0019] A rice straw biochar (RBC) with a mass of 0.02 g was placed in simulated aquaculture wastewater containing Mn(Ⅱ) at concentrations of 10, 20, 40, 80, 100, 120, 160 and 200 mg / L and a volume of 0.2 L. Samples were taken and filtered at t=720 min, and the equilibrium concentration of Mn(Ⅱ) was determined by atomic absorption spectrophotometer to calculate the maximum adsorption capacity of RBC for Mn(Ⅱ).

[0020] Depend on Figure 2 It can be seen that the equilibrium adsorption capacity of rice straw biochar (RBC) for Mn(Ⅱ) increases with the increase of the initial concentration of Mn(Ⅱ). Langmuir (R 2 =0.980) and Freundlich (R 2 =0.979) can well fit the adsorption isotherm data of RBC for Mn(Ⅱ), which indicates that the adsorption process of RBC for Mn(Ⅱ) includes both monolayer chemical adsorption and multilayer physical adsorption. According to the fitting results of Langmuir model, the theoretical maximum adsorption capacity of RBC for Mn(Ⅱ) can reach 405.8 mg / g. Example 3

[0021] 0.1 g of rice straw biochar (RBC) was placed in a simulated aquaculture wastewater containing Mn(Ⅱ) at a concentration of 200 mg / L and a volume of 1.0 L. The rice straw biochar (RBC) saturated with Mn(Ⅱ) was filtered and placed in a freeze dryer at a temperature of -40℃ and a vacuum degree of 30 Pa for freeze drying. The freeze-dried sample was transferred into a high-temperature tube furnace (nitrogen flow rate of 0.1 L / min, heating rate of 10℃ / min) and pyrolyzed at 600℃ for 120 min, and ground through a 100-mesh sieve to obtain Mn self-assembled biochar (Mn@RBC).

[0022] Depend on Figure 3 It can be seen that the surface of RBC is relatively smooth, without obvious branches and impurity particle distribution; the surface of Mn@RBC is rough and covered with a large number of spherical impurity particles. EDS spectrum test was carried out, and the results showed that carbon (C) and oxygen (O) are the main components of RBC and Mn@RBC, and both contain a small amount of silicon (Si). Specifically, the contents of C, O, Si and Mn in RBC are 76.86%, 18.41%, 4.57% and 0.16%, respectively; the contents of C, O, Si and Mn in Mn@RBC are 51.80%, 24.70%, 4.86% and 18.63%, respectively. The content of Mn in Mn@RBC is significantly higher than that in RBC, indicating that the Mn(Ⅱ) adsorbed by RBC is successfully loaded onto the surface of Mn@RBC after pyrolysis and exists in spherical form. Example 4

[0023] The mono-system (RBC, Mn@RBC and E), the binary system (E / Na2SO4, E / RBC, E / Mn@RBC, RBC / Na2SO4 and Mn@RBC / Na2SO4) and the ternary system (E / Na2SO4 / RBC and E / Na2SO4 / Mn@RBC) were constructed to compare their removal abilities for sulfamethoxazole in water, where the voltage was 25 V, the Na2SO4 concentration was 1 mM, the RBC and Mn@RBC dosages were 0.01 g, and the sulfamethoxazole concentration and volume were 5 mg / L and 0.05 L, respectively. The reaction process was carried out on a magnetic stirrer at a speed of 600 rpm, and samples were taken at set time intervals (0-60 min). The residual sulfamethoxazole concentration was determined by high performance liquid chromatography, and the removal rate of sulfamethoxazole at different times was calculated.

[0024] Depend on Figure 4 It can be seen that the removal rates of sulfamethoxazole by the mono-system (RBC, Mn@RBC and E), the binary system (E / RBC, E / Mn@RBC and E / Na2SO4) and the ternary system (E / Na2SO4 / RBC and E / Na2SO4 / Mn@RBC) at t=60 min were 18.3%, 5.7%, 3.4%, 10.7%, 20.0%, 19.4%, 16.5%, 5.1%, 47.4% and 95.6%, respectively. The above results show that the Mn self-assembled biochar (Mn@RBC) can efficiently activate the electrochemically generated persulfate to degrade sulfamethoxazole. Example 5

[0025] In the E / Na2SO4 / Mn@RBC system, the voltage was 10-30 V, the Na2SO4 concentration was 1 mM, the Mn@RBC dosage was 0.01 g, and the concentration and volume of sulfamethoxazole were 5 mg / L and 0.05 L, respectively. The reaction process was carried out on a magnetic stirrer with a speed of 600 rpm, and samples were taken at set time intervals (0-60 min). The residual sulfamethoxazole concentration was determined by high performance liquid chromatography, and the effect of voltage on the ability of the E / Na2SO4 / Mn@RBC system to remove sulfamethoxazole was calculated.

[0026] Figure 5The results show that the removal capacity of E / Na2SO4 / Mn@RBC system for sulfamethoxazole increases with the increase of voltage. When the voltage is 10, 15, 20, 25 and 30 V, the removal rates of E / Na2SO4 / Mn@RBC system for sulfamethoxazole at t=60 min are 36.2%, 50.2%, 75.8%, 95.6% and 96.5%, respectively. When the voltage is 25 and 30 V, there is no significant difference in the removal capacity of E / Na2SO4 / Mn@RBC system for sulfamethoxazole at t=60 min, so the voltage of 25 V is selected for subsequent experiments. Example 6

[0027] In the E / Na2SO4 / Mn@RBC system, the voltage was 25 V, the Na2SO4 concentration was 0.1-5 mM, the Mn@RBC dosage was 0.01 g, and the concentration and volume of sulfamethoxazole were 5 mg / L and 0.05 L, respectively. The reaction process was carried out on a magnetic stirrer with a speed of 600 rpm, and samples were taken at set time intervals (0-60 min). The residual sulfamethoxazole concentration was determined by high performance liquid chromatography, and the effect of Na2SO4 concentration on the ability of the E / Na2SO4 / Mn@RBC system to remove sulfamethoxazole was calculated.

[0028] Depend on Figure 6 It can be seen that when the Na2SO4 concentration is 0.1, 0.5, 1, 2 and 5 mM, the removal rates of sulfamethoxazole by the E / Na2SO4 / Mn@RBC system at t=60 min are 24.1%, 56.0%, 95.6%, 97.6% and 98.1%, respectively. When the Na2SO4 concentration is 1, 2 and 5 mM, there is no significant difference in the removal rate of sulfamethoxazole by the E / Na2SO4 / Mn@RBC system at t=60 min, so the Na2SO4 concentration of 1 mM is selected for subsequent experiments. Example 7

[0029] In the E / Na2SO4 / Mn@RBC system, the voltage was 25 V, the Na2SO4 concentration was 1 mM, the Mn@RBC dosage was 0.0025-0.02 g, and the concentration and volume of sulfamethoxazole were 5 mg / L and 0.05 L, respectively. The reaction process was carried out on a magnetic stirrer with a speed of 600 rpm, and samples were taken at set time intervals (0-60 min). The residual sulfamethoxazole concentration was determined by high performance liquid chromatography, and the effect of Mn@RBC dosage on the ability of E / Na2SO4 / Mn@RBC system to remove sulfamethoxazole was calculated.

[0030] Depend on Figure 7It can be seen that when the dosage of Mn@RBC is 0.0025, 0.005, 0.01, 0.015 and 0.02 g, the removal rates of sulfamethoxazole by the E / Na2SO4 / Mn@RBC system at t=60 min are 45.9%, 76.3%, 95.6%, 97.6% and 98.1%, respectively. When the dosage of Mn@RBC is 0.01, 0.015 and 0.02 g, there is no significant difference in the removal rate of sulfamethoxazole by the E / Na2SO4 / Mn@RBC system at t=60 min. In order to achieve efficient removal of sulfamethoxazole and reduce the operating cost of the system, Mn@RBC with a dosage of 0.01 g was selected for subsequent experiments. Example 8

[0031] In the E / Na2SO4 / Mn@RBC system, the voltage was 25 V, the Na2SO4 concentration was 1 mM, the Mn@RBC dosage was 0.01 g, the concentration and volume of sulfamethoxazole were 5 mg / L and 0.05 L, respectively, and the solution pH was set to 3-11. The reaction process was carried out on a magnetic stirrer with a speed of 600 rpm, and samples were taken at set time intervals (0-60 min). The residual sulfamethoxazole concentration was determined by high performance liquid chromatography, and the effect of solution pH on the ability of E / Na2SO4 / Mn@RBC system to remove sulfamethoxazole was calculated.

[0032] Depend on Figure 8 It can be seen that the removal rates of sulfamethoxazole by the E / Na2SO4 / Mn@RBC system at t=60 min were 98.4%, 95.8%, 88.4%, 80.4% and 49.5% respectively when the solution pH was 3, 5, 7, 9 and 11. The removal rate of SMX by the E / Na2SO4 / Mn@RBC system in the pH range of 3-9 exceeded 80%, indicating that the system has a high tolerance to pH changes. Example 9

[0033] In the E / Na2SO4 / Mn@RBC system, the voltage was 25 V, the Na2SO4 concentration was 1 mM, the Mn@RBC dosage was 0.01 g, the concentration and volume of sulfamethoxazole were 5 mg / L and 0.05 L, respectively, and the water bodies were aquaculture wastewater, sewage effluent, river water, and lake water. The reaction process was carried out on a magnetic stirrer with a speed of 600 rpm. Samples were taken at t=60 min, and the residual sulfamethoxazole concentration was determined by high performance liquid chromatography. The removal capacity of sulfamethoxazole in different actual water bodies by the E / Na2SO4 / Mn@RBC system was calculated.

[0034] Depend on Fig. 9It can be seen that the removal rates of SMX in river water, lake water, sewage effluent and aquaculture wastewater by the E / Na2SO4 / Mn@RBC system at t=60 min were 83.6%, 82.1%, 78.7% and 75.5%, respectively. Example 10

[0035] In the E / Na2SO4 / Mn@RBC system, the voltage was 25 V, the Na2SO4 concentration was 1 mM, the Mn@RBC dosage was 0.01 g, and the concentration and volume of sulfamethoxazole were 5 mg / L and 0.05 L, respectively. The reaction process was carried out on a magnetic stirrer with a speed of 600 rpm. Samples were taken at t=60 min, and the residual sulfamethoxazole concentration was determined by high performance liquid chromatography. After the reaction was completed, the filtered Mn@RBC was freeze-dried and the above catalytic degradation reaction was continued for 2-5 times. The sustainable catalytic degradation ability of Mn@RBC for sulfamethoxazole in the E / Na2SO4 / Mn@RBC system was calculated.

[0036] Depend on Fig.10 It can be seen that the E / Na2SO4 / Mn@RBC system can achieve stable and sustainable degradation of SMX. At t=60 min, the degradation rates of SMX from the first to the fifth cycle were 95.6%, 91.2%, 86.8%, 86.1% and 81.5%, respectively. Embodiment 11

[0037] The voltage in the E / Na2SO4 / Mn@RBC system was 25 V, the Na2SO4 concentration was 1 mM, the Mn@RBC dosage was 0.01 g, and the concentration and volume of sulfamethoxazole were 5 mg / L and 0.05 L, respectively. The reaction process was carried out on a magnetic stirrer with a speed of 600 rpm. Samples were taken at t=60 min, and the dissolution concentration of Mn ions was determined using an atomic absorption spectrophotometer. The above catalytic degradation reaction was continued for 2-5 times and the dissolution concentration of Mn ions was determined. The dissolution level of Mn in the process of sustainable removal of sulfamethoxazole by Mn@RBC in the E / Na2SO4 / Mn@RBC system was calculated.

[0038] Depend on Fig.11 It can be seen that the dissolution concentration of Mn ions did not change significantly during the 1st to 5th cycle reaction. The highest concentration was 0.518 mg / L in the 5th cycle, which is lower than the national drinking water hygiene standard (0.1 mg / L) (GB5749-2022), indicating that Mn@RBC has high safety during use and is not easy to cause secondary pollution to the water body. Example 12

[0039] The voltage in the E / Na2SO4 / Mn@RBC system was 25 V, the Na2SO4 concentration was 1 mM, and the Mn@RBC dosage was 0.01 g. The concentrations and volumes of sulfamethoxazole, ciprofloxacin, chloramphenicol, amoxicillin, and tetracycline were 5 mg / L and 0.05 L, respectively. The reaction process was carried out on a magnetic stirrer at a speed of 600 rpm. At t=60 min, the concentration of residual antibiotics was determined by high performance liquid chromatography, and the removal capacity of the E / Na2SO4 / Mn@RBC system for different antibiotics was calculated.

[0040] Depend on Fig.12 It can be seen that the E / Na2SO4 / Mn@RBC system has a strong removal ability for different types of antibiotics. At t=60 min, the removal rates of sulfamethoxazole, ciprofloxacin, chloramphenicol, amoxicillin and tetracycline by the E / Na2SO4 / Mn@RBC system were 95.6%, 90.7%, 91.5%, 83.9% and 80.6%, respectively.

[0041] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing Mn self-assembled biochar, characterized in that: The following steps are involved: The biochar material saturated with Mn(II) is freeze-dried, pyrolyzed under anaerobic conditions, ground and sieved to obtain Mn self-assembled biochar; the biochar material is selected from at least one of the following: rice straw biochar, corn straw biochar, soybean straw biochar, wheat straw biochar, bagasse biochar and tobacco stem biochar.

2. The preparation method according to claim 1, characterized in that: The biochar material includes biochar obtained by anaerobic pyrolysis of agricultural and / or urban solid waste.

3. The preparation method according to claim 2, characterized in that: Before preparing the biochar material, the process also includes washing and drying agricultural and / or urban solid waste to a constant weight, anaerobic pyrolysis in a tubular furnace, grinding and sieving to obtain the biochar material.

4. The preparation method according to claim 3, characterized in that: The drying temperature is 50-105°C; during the pyrolysis, the nitrogen flow rate is 0.1-0.5 L / min, the heating rate is 5-20°C / min, the pyrolysis temperature is 300-900°C, and the pyrolysis time is 30-480 min; after grinding, the powder is sieved through a 60-200 mesh screen.

5. The preparation method according to claim 1, characterized in that: The method for preparing the biochar material saturated with Mn(II) adsorption comprises using the biochar material to adsorb Mn(II) in simulated aquaculture wastewater, and testing the adsorption capacity of the biochar material for Mn(II); The dosage of the biochar material is 0.01-0.05 g, the concentration of Mn(II) is 10-200 mg / L, and the volume of aquaculture wastewater is 0.1-0.5 L; the freeze-drying temperature is -45°C to -35°C, and the vacuum degree is 20-50 Pa.

6. The preparation method according to claim 1, characterized in that: During the pyrolysis process, the flow rate of nitrogen is 0.1-0.5 L / min, the heating rate is 5-20° C. / min, the pyrolysis temperature is 300-900° C., and the pyrolysis time is 30-480 min; after grinding, the granules are sieved through a 60-200 mesh screen.

7. A Mn self-assembled biochar prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the Mn self-assembled biochar according to claim 7 in the degradation of antibiotics.

9. A method for efficiently activating electrochemically generated persulfate to degrade antibiotics, characterized in that: The method comprises using the Mn self-assembled biochar described in claim 7 as a catalyst to activate electrochemically generated persulfate to degrade antibiotics, and filtering after the oxidation reaction is completed to obtain a solution after the antibiotics have been degraded.

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