Boron-doped modified peanut shell biochar as well as preparation method and application thereof

Abstract

The invention relates to boron-doped modified peanut shell biochar as well as a preparation method and application thereof, the boron-doped modified peanut shell biochar is an irregular particle with a rough surface and a hierarchical pore structure, and the hierarchical pore structure comprises macropores, micropores and mesopores. And in the hierarchical pore structure, macropores account for 1%-30%, mesopores account for 30%-80%, and the balance is micropores. The graphitization degree of the carbon structure is improved, the specific surface area is increased, electron migration is accelerated, and new defect edges and active sites are increased, so that the adsorption and catalysis capabilities are enhanced. And the corresponding preparation method has the advantages of low cost, simplicity and convenience in operation and environment friendliness, and resource utilization of the peanut shells and industrial production of the catalyst can be realized. In addition, the boron-doped modified peanut shell biochar serves as a catalyst to activate potassium peroxydisulfate to degrade antibiotics, and the degradation rate is larger than or equal to 60%.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to boron-doped modified peanut shell biochar and a preparation method and application thereof. Background Art

[0002] With the rapid development of healthcare, agriculture and other industries, antibiotics are widely used to treat various bacterial infections or diseases caused by pathogenic microorganisms. These antibiotics are not fully absorbed by humans and animals, and most of them are discharged into water bodies, seriously threatening ecological security and human health. Due to the complex molecular structure of antibiotics and their difficulty in biodegradation, traditional biochemical treatment processes are difficult to remove them from the water environment.

[0003] The persulfate-based advanced oxidation technology has been proven to be an efficient method for removing refractory organic pollutants from water. This technology uses persulfate as a strong oxidant. After activation by a catalyst, it degrades organic pollutants by free radical oxidation and non-free radical oxidation mechanisms, and converts them into small molecular compounds or mineralizes them into H2O and CO2, thereby achieving the purpose of harmless degradation of organic pollutants. The persulfate-based advanced oxidation technology is easy to operate, has strong oxidation ability, wide redox potential, wide pH adaptability range, and high chemical stability. It has broad application prospects in the treatment of antibiotic wastewater.

[0004] Among many catalysts, transition metal-based homogeneous or heterogeneous catalysts have been shown to have high catalytic activity for activating persulfate. However, these transition metal-based catalysts have the disadvantages of metal leaching and poor stability. Carbon-based materials are a kind of green catalyst. Carbon-based materials such as carbon nanotubes, reduced graphene oxide, and nanodiamonds can effectively activate persulfate, but their high cost, complex preparation process, and low yield limit the widespread application of nanocarbon materials. Summary of the invention

[0005] The purpose of the present invention is to provide a boron-doped modified peanut shell biochar with large specific surface area, rich pore structure, high degree of graphitization and strong catalytic ability, as well as a preparation method and use thereof.

[0006] On the one hand, the present invention provides a boron-doped modified peanut shell biochar, wherein the boron-doped modified peanut shell biochar is in the form of irregular particles with a rough surface and a multi-level pore structure, wherein the multi-level pore structure includes macropores, micropores and mesopores. According to the definition of the International Union of Pure and Applied Chemistry (IUPAC), pores with a diameter less than 2 nm are called micropores; pores with a diameter greater than 50 nm are called macropores; pores with a diameter of 2-50 nm are called mesopores. The pore diameter of the macropores in the present invention is greater than 50 nm and less than 800 nm; the pore diameter of the micropores is greater than 0 and less than 2 nm.

[0007] Furthermore, in the multi-level pore structure of the boron-doped modified peanut shell biochar described in the present application, macropores account for 1% to 30%, mesopores account for 30% to 80%, and the remainder is micropores.

[0008] Furthermore, the boron-doped modified peanut shell biochar described in the present application includes BC3, BC2O and BCO2, and the molar ratio of BC3:BC2O:BCO2 is (1~4):(4~16):(4~10).

[0009] In another aspect, the present invention provides a method for preparing any of the above-mentioned boron-doped modified peanut shell biochars, comprising the following steps: S1: washing, drying, crushing and sieving the collected peanut shells to obtain peanut shell powder; S2: Mix peanut shell powder and boric acid in a mass ratio of 1:(0.5-4), stir magnetically, dry, and grind to obtain a precursor; S3: The precursor is then calcined at 600-1000° C. for 1-3 h in a N2 atmosphere, and then washed, dried, ground, and sieved to obtain the boron-doped modified peanut shell biochar.

[0010] Furthermore, in step S1 of the preparation method of the present invention, the drying temperature is 60-90° C., the drying time is 12-36 hours; the crushing time is 10-60 minutes, and the mesh size of the peanut shell powder is 40-200 meshes; In the step S2, the mixing process of the peanut shell powder and the boric acid is carried out in ultrapure water and magnetically stirred throughout the process, the speed of the magnetic stirring is 100-200 rpm, and the magnetic stirring time is 1-24 h; the magnetic stirring is carried out under oil bath conditions, and the oil bath temperature is 60-80° C.; the drying is carried out under vacuum conditions, and the drying temperature is 60-120° C.; The heating rate of the calcination process in S3 is 2-10°C / min; the washing process is specifically washing with ultrapure water and ethanol at least twice; the drying temperature in S3 is 60-80°C, and the drying time is 12-24 h; the mesh size of the boron-doped modified peanut shell biochar is 40-200 mesh.

[0011] The present invention also provides a use of the boron-doped modified peanut shell biochar described in any one of the above items, wherein the boron-doped modified peanut shell biochar is used as a catalyst.

[0012] Furthermore, the boron-doped modified peanut shell biochar of the present invention is used as an activation catalyst when potassium persulfate is used to degrade antibiotics.

[0013] Furthermore, the antibiotics described in the present invention are any one or more of tetracycline, oxytetracycline, levofloxacin, norfloxacin, sulfamethoxazole, and ciprofloxacin.

[0014] Furthermore, the boron-doped modified peanut shell biochar of the present invention is added as a catalyst and potassium persulfate into wastewater containing antibiotics, stirred, and subjected to a catalytic degradation reaction to complete the degradation of the antibiotics in the wastewater; The initial concentration of antibiotics in the wastewater: catalyst: potassium persulfate is (10-100 mg / L): (10-200 mg / L): (2-50 mmol / L); the pH value of the wastewater is 3-11; The degradation rate of antibiotics in the degradation process containing activated catalysts is ≥60%.

[0015] Furthermore, the boron-doped modified peanut shell biochar of the present invention activates potassium persulfate to produce • OH radicals, Free radicals, Free radicals and 1 The number ratio of O2 non-free radicals is (2-10): (1-5): (1-5): (1-5). The free radicals are detected by electron paramagnetic resonance technology, specifically using DMPO and TEMPO as free radical scavengers, the central magnetic field is 3500.00 G, the sweep width is 200.00 G, the sweep time is 30.00 s, the microwave power is 19.45 mW, the modulation amplitude is 1.000 G, the switching time is 40.0 ms, and the frequency is 9.852508 GHz.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects: The invention provides a boron-doped modified peanut shell biochar and a preparation method thereof. First, peanut shell powder is immersed in a boric acid solution and then pyrolyzed to obtain the boron-doped modified peanut shell biochar. On the one hand, during the pyrolysis process, the boric acid molecules loaded on the peanut shell are first decomposed into B2O3, and then B2O3 is used as an active substance in the doping process to promote the formation of BCO2 and BC2O in the carbon structure, and finally the amount of BC3:BC2O:BCO2 is (1-4): (4-16): (4-10). The obtained boron-doped modified peanut shell biochar is an irregular granular with a rough surface and a multi-level pore structure, wherein the multi-level pore structure includes macropores, micropores and mesopores, and the macropores account for 1%-30% of the multi-level pore structure, the number of mesopores accounts for 30%-80%, and the remainder is micropores. Boron-doped modified biochar improves the graphitization degree of the carbon structure, increases the specific surface area, accelerates electron migration, and adds new defect edges and active sites, thereby enhancing its adsorption and catalytic capabilities. On the other hand, the low-cost and easy-to-operate preparation method has the advantages of being green and environmentally friendly, and can realize the resource utilization of peanut shells and the industrial production of catalysts.

[0017] Secondly, peanut shells are biochar materials with a wide range of raw materials, simple preparation process, low cost, large specific surface area, and rich surface functional groups. They are ideal catalysts to replace nanocarbon materials. At the same time, they can also avoid the risk of secondary pollution caused by the leakage of loaded metal ions in metal doping modification.

[0018] Furthermore, the boron-doped modified peanut shell biochar of the present invention is used as a catalyst to activate potassium persulfate to degrade antibiotics. This is the first time that the boron-doped modified peanut shell biochar catalyst has been applied to a persulfate advanced oxidation system. • OH), superoxide anion ( )、sulfate radical( ) dominated by free radical oxidation pathways and singlet oxygen ( 1 O2)-dominated non-radical oxidation pathway efficiently degrades antibiotics. Moreover, the boron-doped modified peanut shell biochar activated potassium persulfate produced by the present application • OH radicals, Free radicals, Free radicals and 1 The number ratio of O2 non-free radicals is (2~10):(1~5):(1~5):(1~5). The degradation rate of antibiotics in the degradation process containing activated catalyst is ≥60%. It can be widely used in the removal of difficult-to-degrade organic matter in water, realize the resource utilization of solid waste, and has application prospects in actual water treatment.

[0019] The boron-doped modified peanut shell biochar of the present invention, as a catalyst, exhibits excellent degradation performance for tetracycline hydrochloride in a wide pH range of 3.0 to 11.0. Under extremely alkaline conditions of pH 11, the degradation efficiency of tetracycline can still reach 64%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a scanning electron microscope image of the boron-doped modified peanut shell biochar described in Example 1 of the present invention; Figure 2 Scanning electron microscope image of the undoped modified peanut shell biochar described in Comparative Example 1 of the present invention; Figure 3 N2 adsorption-desorption isotherms of the samples in Example 1 and Comparative Example 1 of the present invention; Figure 4 It is the B 1s element peak diagram of the samples in Example 1 and Comparative Example 1 of the present invention; Figure 5 The degradation effect diagram of tetracycline by activation of potassium persulfate in samples of Example 1 and Comparative Example 1 of the present invention is shown; Figure 6 Electron paramagnetic resonance test of potassium persulfate activated by B-doped modified peanut shell biochar (B4BC) in Example 5 of the present invention (a) DMPO capture and • OH, (b) DMPO capture , (c) TEMPO capture 1 O2; Figure 7 The degradation effect diagram of tetracycline in Examples 6 to 10 of the present invention is shown; Figure 8 These are the effect diagrams of degrading different antibiotics in Examples 11 to 14 of the present invention. DETAILED DESCRIPTION

[0021] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described in detail with reference to the accompanying drawings. The described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the specific implementation method, they shall be carried out according to the conventional conditions or the conditions provided by the manufacturer.

[0022] When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims. The terms used in the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0023] The present invention is further described in detail below with reference to specific embodiments. Specific implementation method one: The invention provides a boron-doped modified peanut shell biochar, which is in the form of irregular particles with a rough surface and a multi-level pore structure, wherein the multi-level pore structure includes macropores, micropores and mesopores.

[0025] In other embodiments of the present invention, in the multi-level pore structure of the boron-doped modified peanut shell biochar, macropores account for 1% to 30%, mesopores account for 30% to 80%, and the remainder is micropores.

[0026] In other embodiments of the present invention, the boron-doped modified peanut shell biochar includes BC3, BC2O and BCO2, and the molar ratio of BC3:BC2O:BCO2 is (1~4):(4~16):(4~10). Specific implementation method 2: A method for preparing boron-doped modified peanut shell biochar based on any of the above specific embodiments comprises the following steps: S1: washing, drying, crushing and sieving the collected peanut shells to obtain peanut shell powder; S2: Mix peanut shell powder and boric acid in a mass ratio of 1:(0.5-4), stir magnetically, dry, and grind to obtain a precursor; S3: The precursor is then calcined at 600-1000° C. for 1-3 h in a N2 atmosphere, and then washed, dried, ground, and sieved to obtain the boron-doped modified peanut shell biochar.

[0028] In other embodiments of the present invention, in step S1, the drying temperature is 60-90° C., the drying time is 12-36 h; the crushing time is 10-60 min, and the mesh size of the peanut shell powder is 40-200 mesh; In the step S2, the mixing process of the peanut shell powder and the boric acid is carried out in ultrapure water and magnetically stirred throughout the process, the speed of the magnetic stirring is 100-200 rpm, and the magnetic stirring time is 1-24 h; the stirring is carried out under oil bath conditions, and the oil bath temperature is 60-80° C.; the drying is carried out under vacuum conditions, and the drying temperature is 60-120° C.; The heating rate of the calcination process in S3 is 2-10°C / min; the washing process is specifically washing with ultrapure water and ethanol at least twice; the drying temperature in S3 is 60-80°C, and the drying time is 12-24 h; the mesh size of the boron-doped modified peanut shell biochar is 40-200 mesh. Specific implementation method three: A use of the boron-doped modified peanut shell biochar according to any one of the above specific embodiments, wherein the boron-doped modified peanut shell biochar is used as a catalyst.

[0030] In other embodiments of the present invention, the boron-doped modified peanut shell biochar is used as an activation catalyst when potassium persulfate is used to degrade antibiotics.

[0031] In other embodiments of the present invention, the antibiotic is any one or more of tetracycline, oxytetracycline, levofloxacin, norfloxacin, sulfamethoxazole, and ciprofloxacin.

[0032] In other embodiments of the present invention, the boron-doped modified peanut shell biochar is added as a catalyst and potassium persulfate to wastewater containing antibiotics, stirred, and subjected to a catalytic degradation reaction to complete the degradation of the antibiotics in the wastewater; The initial concentration of antibiotics in the wastewater: catalyst: potassium persulfate is (10-100 mg / L): (10-200 mg / L): (2-50 mmol / L); the pH value of the wastewater is 3-11; The degradation rate of antibiotics in the degradation process containing activated catalysts is ≥60%.

[0033] In other embodiments of the present invention, the boron-doped modified peanut shell biochar activated potassium persulfate to produce • OH radicals, Free radicals, Free radicals and 1 The number ratio of O2 non-free radicals is (2~10):(1~5):(1~5):(1~5).

[0034] Embodiment 1: A method for preparing boron-doped modified peanut shell biochar comprises the following steps: The collected peanut shells are washed, dried, crushed, and sieved (100 mesh) to obtain peanut shell powder. The drying temperature is 60-90°C, the drying time is 12-36 h, and the crushing time is 10-60 min.

[0035] Peanut shell powder and boric acid are mixed in a mass ratio of 1:4, magnetically stirred, dried, and ground to obtain a boron-doped modified peanut shell biochar precursor; the mixing process of peanut shell powder and boric acid is carried out in ultrapure water and magnetically stirred throughout the process, the magnetic stirring speed is 100-200 rpm, and the magnetic stirring time is 1-24 h; the magnetic stirring is carried out under oil bath conditions, and the oil bath temperature is 60-80°C; the drying is carried out under vacuum conditions, and the drying temperature is 60-120°C.

[0036] The boron-doped modified peanut shell biochar precursor was transferred to the Ark, calcined in a tube furnace for 2 h at a temperature of 900 ° C in a N2 atmosphere, and then washed, dried, ground, and sieved to obtain the boron-doped modified peanut shell biochar, sample 1, denoted as B4BC. The heating rate of the calcination process was 2-10 ° C / min; the washing process was specifically washed at least twice with ultrapure water and ethanol; the drying temperature in S3 was 60-80 ° C, and the drying time was 12-24 h.

[0037] Embodiment 2: The only difference between Example 2 and Example 1 is that peanut shell powder and boric acid are mixed in a mass ratio of 1:0.5 to finally obtain sample 2#.

[0038] Embodiment 3: The only difference between Example 3 and Example 1 is that the precursor is calcined at 600° C. to finally obtain Sample #3.

[0039] Embodiment 4: The only difference between Example 4 and Example 1 is that the precursor is calcined at 1000° C. to finally obtain sample #4.

[0040] Comparative Example 1: As in Example 1, the collected peanut shells were washed, dried, crushed, and sieved (100 meshes) to obtain peanut shell powder.

[0041] The peanut shell powder was directly placed in an ark and calcined in a tube furnace for 2 h at 900 °C, and then washed, dried, ground, and sieved. The operating conditions were the same as those in Example 1 to obtain undoped modified peanut shell biochar, which was recorded as BC.

[0042] Comparative Example 2: The only difference between this comparative example 2 and example 1 is that peanut shell powder and boric acid are mixed in a mass ratio of 1:0.4 to finally obtain sample 5#. Insufficient boric acid will result in insufficient acid etching effect on biochar, insufficient defect level to generate new active sites, and too few BCO2 active sites generated.

[0043] Comparative Example 3: The only difference between this comparative example 3 and example 1 is that peanut shell powder and boric acid are mixed in a mass ratio of 1:5 to finally obtain sample 6#. Excessive boric acid will cause excessive acid etching of biochar, destroy the pore structure, and fail to significantly increase the number of BCO2 active sites. It also increases costs and causes waste.

[0044] Comparative Example 4: The difference between this comparative example 4 and example 1 is that the precursor is calcined at 500° C. to finally obtain sample #7. If the temperature is too low, the graphitization degree of the obtained material is low, and if the temperature is too low, it is not conducive to the doping of B element.

[0045] Comparative Example 5: The only difference between Comparative Example 5 and Example 1 is that the precursor is calcined at 1200° C. to finally obtain Sample #8. Too high a temperature causes the pore structure of the biochar material to collapse, resulting in a decrease in the specific surface area, affecting adsorption and causing the active sites to be covered, which is not conducive to the catalytic reaction.

[0046] from Figure 1 and Figure 2 By comparison, it can be seen that Figure 2 The surface of the BC sample prepared in Comparative Example 1 is smooth and does not show obvious void structure. After adding boric acid, Figure 1 The surface of sample 1#, B4BC, prepared in Example 1 is rough and exhibits an obvious multi-level pore structure. This is because the boric acid impregnation treatment destroys the cellulose, hemicellulose and lignin structures in the peanut shells, thereby promoting the formation of a developed multi-level pore structure in the peanut shells after heat treatment and carbonization.

[0047] Depend on Figure 3 It can be seen that the BC sample isotherm prepared in Comparative Example 1 is Type I with an H4 hysteresis loop, indicating that it is mainly a microporous structure, while the 1# sample prepared in Example 1 exhibits a Type IV isotherm and an H3 hysteresis loop, indicating that its pore structure is mainly micropores and mesopores, and when the relative pressure approaches 1.0, the adsorption amount of nitrogen in Example 1 surges, indicating the presence of macropores. Therefore, the introduction of boron forms a multi-level pore structure, that is, macropores are conducive to the passage of substances, while micropores and mesopores provide sufficient specific surface area and active sites, which is beneficial to the adsorption and catalytic degradation of antibiotics by the material.

[0048] from Figure 4 It can be seen that the fitted peaks are at 190.07 eV, 191.54 eV and 192.71 eV, corresponding to BC3, BC2O and BCO2, respectively, indicating that the B atom has been successfully introduced into the carbon framework. The introduction of the B element forms active sites, which greatly improves the degradation performance of the biochar material.

[0049] Embodiment 5: A use of boron-doped modified peanut shell biochar, specifically comprising the following steps: Take 2 portions of 100 mL and 40 mg / L tetracycline solution and add them to two 250 mL beakers respectively. At this time, the initial pH value of the solution in the beaker is 5.75. Then, 12 mg of boron-doped modified peanut shell biochar (B4BC) prepared in Example 1 and 12 mg of undoped modified peanut shell biochar (BC) prepared in Comparative Example 1 were added as catalysts, and 5 mmol / L potassium persulfate PDS was added at the same time. The reaction was carried out in a shaker in the dark, with a stirring rate of 100-500 rpm, and catalytic degradation was carried out at room temperature. Samples were taken at regular intervals, and the clear solution was filtered with a 0.22 μm filter. An equal amount of methanol was added, and the tetracycline concentration was measured with a UV-visible spectrophotometer at a wavelength of 357 nm.

[0050] from Figure 5 It can be seen that within the 30 min reaction time, the undoped peanut shell biochar (BC) was the most catalytic, with a degradation efficiency of only 7% for tetracycline hydrochloride (40 mg / L), while the boron-doped peanut shell biochar (B4BC) had a degradation efficiency of 88%. The degradation efficiency of the boron-doped peanut shell biochar was 12.57 times that of the undoped one. Boron doping introduced new active sites, thereby improving the catalytic activity of biochar for PDS.

[0051] from Figure 6 It can be seen that the activation of potassium persulfate by boron-doped peanut shell biochar (B4BC) mainly produces • OH, , Free radicals and 1 O2 is not a free radical. And it can be detected by electron paramagnetic resonance technology. • OH radicals, Free radicals, Free radicals and 1The number ratio of O2 non-radicals is (2~10):(1~5):(1~5):(1~5). Specifically, DMPO and TEMPO are used as free radical scavengers, the central magnetic field is 3500.00 G, the sweep width is 200.00 G, the sweep time is 30.00 s, the microwave power is 19.45 mW, the modulation amplitude is 1.000 G, the conversion time is 40.0 ms, and the frequency is 9.852508 GHz. These active oxygen species play an important role in the degradation of antibiotics, and the order of their role is: • OH > > > 1 O2. It can be seen that the active sites on the surface of boron-doped modified peanut shell biochar (B4BC) as active centers can effectively adsorb potassium persulfate molecules and further catalytically activate them to produce active oxygen with high reactivity.

[0052] Embodiment 6: The only difference between Example 6 and Example 5 is that after 100 mL and 40 mg / L tetracycline solution were added to a 250 mL beaker, respectively, the initial pH value of the solution was adjusted to 3 with 0.1 M HCl and 0.1 M HCl, and then 20 mg of the boron-doped modified peanut shell biochar prepared in Example 1 was added as a catalyst, and 2.5 mmol / L potassium persulfate PDS was added at the same time.

[0053] Embodiment 7: The only difference between Example 7 and Example 6 is that the initial pH value of the solution is adjusted to 5 using 0.1 M HCl and 0.1 M NaOH.

[0054] Embodiment 8: The only difference between Example 8 and Example 6 is that the initial pH value of the solution is adjusted to 7 using 0.1 M HCl and 0.1 M NaOH.

[0055] Embodiment 9: The only difference between Example 9 and Example 6 is that the initial pH value of the solution is adjusted to 9 using 0.1 M HCl and 0.1 M NaOH.

[0056] Embodiment 10: The only difference between Example 10 and Example 6 is that the initial pH value of the solution is adjusted to 11 using 0.1 M HCl and 0.1 M NaOH.

[0057] Comparative Example 6: The difference between this comparative example 6 and example 6 is that the initial pH value of the solution is adjusted to 1 by using 0.1 M HCl and 0.1 M NaOH. Under strong acidic conditions with a pH value of less than 3.3, the tetracycline molecule TCH is positively charged, mainly in the form of TCH3+. Since the surface of B4BC has abundant oxygen-containing functional groups such as -COOH and -OH, the interaction between B4BC and TCH and the hydrogen bond interaction are enhanced, and the adsorption capacity is strong.

[0058] Comparative Example 7: The difference between this comparative example 7 and example 6 is that the initial pH value of the solution is adjusted to 13 with 0.1 M HCl and 0.1 M NaOH. The tetracycline molecule TCH is gradually deprotonated, and its electron-accepting ability is weakened, resulting in a decrease in the adsorption capacity of B4BC to TCH. Under alkaline conditions, TCH exists in the form of anions. At this time, the surface of B4BC carries a negative charge, and a strong electrical repulsion occurs between the electronegative B4BC and the negatively charged TCH, which inhibits the adsorption of B4BC to TCH, thereby affecting the removal effect of TCH.

[0059] from Figure 7 It can be seen that the boron-doped modified peanut shell biochar as a catalyst shows excellent degradation performance for tetracycline hydrochloride in a wide pH range of 3.0~11.0. Under the extremely alkaline condition of pH 11, the degradation efficiency of tetracycline can still reach 64%.

[0060] Embodiment 11: A 20 mg / L oxytetracycline (OTC) solution was prepared, 100 mL of the solution to be degraded was placed in a 250 mL beaker, and then 20 mg of the boron-doped modified peanut shell biochar catalyst (B4BC) prepared in Example 1 was added, and 2.5 mmol / L potassium persulfate PDS was added at the same time, and the reaction was carried out in a shaker in the dark, and the catalytic degradation was carried out at room temperature. Samples were taken at regular intervals, and the clear liquid was filtered with a 0.22 μm filter, an equal amount of methanol was added, and the tetracycline concentration was measured with a UV-visible spectrophotometer at a wavelength of 357 nm.

[0061] Embodiment 12: The only difference between Example 12 and Example 11 is that the solution to be degraded is 20 mg / L, 100 mL of levofloxacin (LEV).

[0062] Embodiment 13: The only difference between Example 13 and Example 11 is that the solution to be degraded is 20 mg / L, 100 mL of norfloxacin (NOR).

[0063] Embodiment 14: The only difference between Example 14 and Example 11 is that the solution to be degraded is 20 mg / L, 100 mL of ciprofloxacin (CIP).

[0064] from Figure 8 It can be seen that the boron-doped modified peanut shell biochar (B4BC) and potassium persulfate advanced oxidation system have a good degradation effect on the four antibiotics, oxytetracycline, levofloxacin, norfloxacin and ciprofloxacin, and the removal rate can reach more than 60% within 30 minutes.

[0065] The present invention is described by the above specific embodiments, and those skilled in the art should understand that various changes and equivalent substitutions can be made to the present invention without departing from the scope of the present invention. The parts not described in detail in the present specification are well-known technologies to those skilled in the art. In addition, various modifications can be made to the present invention for specific situations or specific circumstances without departing from the scope of the present use. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all implementation methods falling within the scope of the claims of the present invention.

Claims

1. A boron-doped modified peanut shell biochar, characterized in that: The boron-doped modified peanut shell biochar is in the form of irregular particles with a rough surface and a multi-level pore structure, wherein the multi-level pore structure includes macropores, micropores and mesopores.

2. The boron-doped modified peanut shell biochar according to claim 1, characterized in that: In the multi-level pore structure of the boron-doped modified peanut shell biochar, macropores account for 1% to 30%, mesopores account for 30% to 80%, and the remainder is micropores.

3. The boron-doped modified peanut shell biochar according to claim 1, characterized in that: The boron-doped modified peanut shell biochar includes BC3, BC2O and BCO2, and the molar ratio of BC3:BC2O:BCO2 is (1-4):(4-16):(4-10).

4. A method for preparing boron-doped modified peanut shell biochar according to any one of claims 1 to 3, characterized in that: The preparation method comprises the following steps: S1: washing, drying, crushing and sieving the collected peanut shells to obtain peanut shell powder; S2: peanut shell powder and boric acid are mixed in a mass ratio of 1:(0.5-4), magnetically stirred, dried, and ground to obtain a precursor; S3: The precursor is then calcined at 600-1000° C. for 1-3 h in a N2 atmosphere, and then washed, dried, ground, and sieved to obtain the boron-doped modified peanut shell biochar.

5. The preparation method according to claim 4, characterized in that: In the step S1, the drying temperature is 60-90° C., the drying time is 12-36 h, the crushing time is 10-60 min, and the mesh size of the peanut shell powder is 40-200 mesh; In the step S2, the mixing process of the peanut shell powder and the boric acid is carried out in ultrapure water and magnetically stirred throughout the process, the speed of the magnetic stirring is 100-200 rpm, and the magnetic stirring time is 1-24 h; the magnetic stirring is carried out under oil bath conditions, and the oil bath temperature is 60-80° C.; the drying is carried out under vacuum conditions, and the drying temperature is 60-120° C.; The heating rate of the calcination process in S3 is 2-10°C / min; the washing process is specifically washing with ultrapure water and ethanol at least twice; the drying temperature in S3 is 60-80°C, and the drying time is 12-24 h; the mesh size of the boron-doped modified peanut shell biochar is 40-200 mesh.

6. A use of boron-doped modified peanut shell biochar, characterized in that: The boron-doped modified peanut shell biochar is the boron-doped modified peanut shell biochar described in any one of claims 1 to 3, and the boron-doped modified peanut shell biochar prepared by the preparation method of the boron-doped modified peanut shell biochar described in any one of claims 4 or 5, and the boron-doped modified peanut shell biochar is used as a catalyst.

7. The use according to claim 6, characterized in that The boron-doped modified peanut shell biochar is used as an activation catalyst when potassium persulfate degrades antibiotics.

8. The use according to claim 7, characterized in that The antibiotic is any one or more of tetracycline, oxytetracycline, levofloxacin, norfloxacin, sulfamethoxazole, and ciprofloxacin.

9. The use according to claim 8, characterized in that The boron-doped modified peanut shell biochar is added as a catalyst and potassium persulfate into the wastewater containing antibiotics, stirred, and catalytically degraded to complete the degradation of the antibiotics in the wastewater; The initial concentration of antibiotics in the wastewater: catalyst: potassium persulfate is (10-100 mg / L): (10-200 mg / L): (2-50 mmol / L); the pH value of the wastewater is 3-11; The degradation rate of antibiotics in the degradation process containing activated catalysts is ≥60%.

10. The use according to claim 9, characterized in that The boron-doped modified peanut shell biochar activated potassium persulfate to produce • OH radicals, Free radicals, Free radicals and 1 The number ratio of O2 non-free radicals is (2~10):(1~5):(1~5):(1~5).

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