Boron-doped biochar for promoting tobacco growth, preparation method, catalytic system and application

Abstract

The present invention relates to the technical field of pesticide degradation, and specifically to boron-doped biochar, a preparation method, a catalytic system, and an application thereof for promoting tobacco growth. The boron-doped biochar is prepared by the preparation method. The preparation method comprises adding a boron source to water, heating and dissolving the boron source, then adding a carbon source, and stirring the mixture to obtain a mixed solution; heating and evaporating the mixed solution under stirring conditions to obtain a concentrate; and drying and calcining the concentrate to obtain the boron-doped biochar. The catalytic system comprises adding persulfate to the boron-doped biochar. The application is the application of the catalytic system in catalytic degradation of dichloroquinoline. The present invention can significantly improve the catalytic degradation performance of dichloroquinoline and promote tobacco growth.

Description

Technical Field

[0001] The present invention relates to the technical field of pesticide degradation, and in particular to boron-doped biochar for promoting tobacco growth, a preparation method, a catalytic system and applications. Background Art

[0002] Quinclorac is widely used in rice paddies for its excellent barnyardgrass control. However, it is difficult to degrade naturally in soil and water. Residual quinclorac can cause phytotoxicity to Solanaceae crops such as tobacco, eggplant, and peppers, severely impacting crop quality and yield. Rapidly and effectively removing residual quinclorac from water and soil to minimize its impact on the agricultural environment is a current research hotspot.

[0003] Currently, the main methods for removing residual quinclorac from water and soil include adsorption, photocatalytic degradation, microbial degradation, and catalytic persulfate-based advanced oxidation degradation. While adsorption is simple to operate, it merely transfers the pollutant from one phase to another and does not fundamentally address the problem. Photocatalytic degradation requires specific light source conditions. Microbial degradation offers advantages such as low cost, good environmental compatibility, and suitability for large-scale application. However, quinclorac-degrading bacteria face challenges such as difficulty in selecting dominant strains and poor field survival, and most research remains limited to the laboratory stage. In contrast, catalytic persulfate-based advanced oxidation technologies offer advantages such as cost-effectiveness, high efficiency, environmental friendliness, safety, and stability, as they generate strong oxidizing species that can mineralize the organic pollutant quinclorac into non-toxic CO2, H2O, and other small molecules. However, existing catalytic persulfate-based advanced oxidation technologies often use metal elements such as iron, cobalt, and nickel as modifiers, and the introduced metals may cause secondary environmental pollution. In response to this, researchers have used carbon-based materials to activate persulfate to degrade herbicides. This carbon-based material requires no additional energy, produces no secondary pollution, and can improve soil properties, making it an emerging green activator material. However, these carbon-based materials, such as carbon nanotubes, graphene, and activated carbon fibers, have drawbacks such as complex preparation processes and high costs.

[0004] Biochar produced from agricultural waste offers advantages such as a wide range of raw materials, low cost, and simple preparation. However, unmodified biochar suffers from limitations such as a limited number of surface active sites and low catalytic degradation efficiency. Surface modification of biochar, such as doping with one or two non-metallic elements such as nitrogen, phosphorus, or sulfur, can modulate its physical and chemical properties, increase its surface active sites, and enhance its catalytic performance. Boron, a nutrient required by crops, has an atomic radius similar to that of carbon atoms. During high-temperature preparation, it more readily forms covalent bonds with carbon oxygen, enhancing the degree of graphitization and increasing the number of catalytically active functional groups on the biochar surface. However, the catalytic activity of boron-doped biochar materials is affected by multiple factors, including the boron doping level, preparation temperature, and biomass type. Currently, most methods for preparing boron-doped biochar use a two-step process: a low-temperature hydrothermal reaction to produce hydrothermal carbon, followed by high-temperature oxygen-limited pyrolysis to produce the boron-doped biochar. This preparation process is cumbersome and time-consuming.

[0005] In summary, it is necessary to provide boron-doped biochar, preparation method, catalytic system and application for promoting tobacco growth, so as to solve the problem that the preparation process of boron-doped biochar in the prior art is cumbersome and time-consuming. Summary of the Invention

[0006] The present invention aims to provide boron-doped biochar for promoting tobacco growth, a preparation method, a catalytic system, and applications. The specific technical solutions are as follows:

[0007] In a first aspect, the present invention provides a method for preparing boron-doped biochar for promoting tobacco growth, comprising adding a boron source to water, heating and dissolving the boron source, adding a carbon source, and stirring the mixture to obtain a mixed solution; heating and evaporating the mixed solution under stirring to obtain a concentrate; and drying and calcining the concentrate to obtain boron-doped biochar for promoting tobacco growth.

[0008] In the mixed solution, the mass ratio of the boron source, the water and the carbon source is 2-6:40-60:2-10.

[0009] Preferably, the boron source includes at least one of boric acid, borax, sodium borate and boron oxide.

[0010] Preferably, the carbon source comprises at least one of waste tea residues, fruit peels, fruit shells, tobacco straws and reed straws.

[0011] Preferably, the heating temperature used for the heating dissolution is 50°C-90°C; the heating temperature used for the heating evaporation is 50°C-90°C.

[0012] Preferably, the drying temperature used in the drying treatment is 60° C.-90° C., and the drying time is 12 h-24 h.

[0013] Preferably, the calcination temperature used in the calcination treatment is 550°C-650°C, and the calcination time is 2h-4h; the heating rate used before heating to the calcination temperature is 5-10°C / min; the cooling rate used after the calcination is 10-15°C / min; inert gas is introduced during the calcination process, and the flow rate of the inert gas is controlled to be 200-800mL / min.

[0014] Preferably, a post-treatment is further included after the calcination treatment, and the post-treatment includes alcohol washing and water washing of the boron-doped biochar.

[0015] In a second aspect, the present invention provides a boron-doped biochar prepared by the method for preparing boron-doped biochar.

[0016] In a third aspect, the present invention provides a catalytic system of boron-doped biochar, the catalytic system comprising adding persulfate to the boron-doped biochar; the mass ratio of the boron-doped biochar to the persulfate is 0.01-0.025:0.0228-0.456; the persulfate comprises ammonium persulfate.

[0017] In a fourth aspect, the present invention provides an application of the catalytic system using the boron-doped biochar in catalytic degradation of quinclorac.

[0018] The application of the technical solution of the present invention has at least the following beneficial effects:

[0019] (1) The preparation method of boron-doped biochar for promoting tobacco growth provided by the present invention adopts a mixture of a boron source and a carbon source to prepare boron-doped biochar, which can increase the catalytic active functional groups (such as BCO2 and BC2O) on the surface of biochar, and at the same time, by adjusting the electron distribution on the carbon surface, greatly enhance the electron-donating ability of biochar, resulting in the catalysis of ammonium persulfate to produce more active species such as sulfate radicals (SO4 ·- ), hydroxyl radicals (·OH), superoxide radicals (O2 ·- ) and singlet oxygen ( 1 O2), etc., thereby significantly improving the catalytic degradation performance of dichloroquinoline.

[0020] (2) The present invention uses a carbon source rich in nutrient elements as a raw material and a boron source as a modifier, and adopts a one-step pyrolysis method to prepare a boron-doped biochar with excellent catalytic performance for ammonium persulfate. This preparation method is simple, easy and low-cost.

[0021] (3) The oxidant selected in the catalytic system of the present invention is ammonium persulfate, and the nitrogen in ammonium persulfate is an essential nutrient for crop growth. The catalytic system composed of boron-doped biochar and ammonium persulfate in the present invention not only degrades dichloroquinoline residues in the soil, but also provides nutrients for tobacco growth, thereby promoting tobacco growth.

[0022] (4) The present invention provides an application of a catalytic system using boron-doped biochar for the catalytic degradation of quinclorac. The application is mainly developed to address the reality that in the tobacco-rice rotation area in the south, the residues of herbicides such as quinclorac used in the previous crop rice fields are prone to cause phytotoxicity to the next crop tobacco. Boron-doped biochar can quickly catalyze the degradation of quinclorac by ammonium persulfate. Compared with other catalytic systems (such as heavy metals Co, Fe, Ni or Mn catalyzing persulfate), the catalytic system does not contain harmful heavy metal elements. It is composed of boron-doped biochar and ammonium persulfate. It can not only efficiently catalyze the degradation of quinclorac, but also the nutrients contained in the catalytic system, such as boron, ammonium nitrogen and organic matter, can provide nutrients for the growth of crops, thereby having the dual effects of reducing pollution and increasing fertilizer.

[0023] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0025] Figure 1 Scanning electron micrographs of the non-boron-doped biochar prepared in Comparative Example 1, and the boron-doped biochars prepared in Example 1 and Comparative Examples 2-3 at different calcination temperatures;

[0026] Figure 2 The curve of quinclorac concentration changing with different amounts of boron-doped biochar in the catalytic system at different reaction times t is shown in Figure 2. Figure 2 0.125 g·L -1 The mass concentration of the boron-doped biochar in Comparative Example 4 is 0.0063 g in 50 mL of quinclorac aqueous solution; 0.25 g·L -1 The mass concentration of boron-doped biochar in Example 4 is 0.0125 g in 50 mL of quinclorac aqueous solution; 0.50 g·L -1 represents the mass concentration of 0.0250 g of boron-doped biochar in 50 mL of quinclorac aqueous solution in Example 5);

[0027] Figure 3 The curve of the concentration of quinclorac at different reaction times t changes with the amount of ammonium persulfate in the catalytic system ( Figure 30.1 mM indicates that the amount of ammonium persulfate used in Example 6 is 0.1 mmol; 0.5 mM indicates that the amount of ammonium persulfate used in Example 5 is 0.5 mmol; 1 mM indicates that the amount of ammonium persulfate used in Example 7 is 1.0 mmol; 2 mM indicates that the amount of ammonium persulfate used in Example 8 is 2.0 mmol);

[0028] Figure 4 is the degradation rate of quinclorac as the reaction time changes under different pH conditions;

[0029] Figure 5 The XPS spectra of boron-doped biochar before and after reaction in Example 1 in Table 1 ( Figure 5 (a)-(c) are XPS spectra of boron-doped biochar before reaction; (d)-(f) are XPS spectra of boron-doped biochar after reaction).

[0030] Figure 6 It is the result of characterization of active substances using electron paramagnetic resonance technology;

[0031] Figure 7 It is the degradation pathway of quinclorac;

[0032] Figure 8 This figure shows the effects of different treatments on quinclorac phytotoxicity in tobacco seedlings. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention are within the scope of protection of the present invention.

[0034] Example 1:

[0035] The preparation method of boron-doped biochar for promoting tobacco growth comprises the following steps: adding a boron source (specifically boric acid) to water (specifically distilled water), heating (specifically heating at 70° C.) to dissolve the boron source, adding a carbon source (specifically waste tea residue, having an organic carbon content of 32.82%, a nitrogen content of 4.89%, a P2O5 content of 0.65%, and a K2O content of 1.96%), and stirring the mixture to obtain a mixed solution; heating the mixed solution under stirring (specifically heating at 70° C.) and evaporating the mixture to dryness to obtain a concentrate; and drying the concentrate (specifically drying at 60° C. for 24 hours) and calcining the concentrate to obtain the boron-doped biochar for promoting tobacco growth.

[0036] In the mixed liquid, the mass ratio of the boron source, the water and the carbon source is 4:60:2.

[0037] The calcination treatment adopts a calcination temperature of 600°C and a calcination time of 2 hours; the heating rate adopted before the temperature is raised to the calcination temperature is 5°C / min; the cooling rate adopted after the calcination is completed is 10°C / min, and an inert gas is introduced during the calcination process, and the flow rate of the inert gas is controlled to be 200 mL / min; wherein, the inert gas is nitrogen, and its flow rate is controlled to be 200 mL / min, so as to exhaust the air in the calcination furnace and achieve the purpose of oxygen limitation.

[0038] After the calcination treatment, a post-treatment is also included, and the post-treatment includes alcohol washing (specifically, using ethanol to wash the boron-doped biochar once to wash away tar and other organic matter produced by biomass pyrolysis) and water washing (specifically, using distilled water to wash the boron-doped biochar until it is neutral) of the boron-doped biochar.

[0039] Example 2:

[0040] Different from Example 1, in the mixed solution, the mass ratio of the boron source, the water and the carbon source is 2:60:2.

[0041] Example 3:

[0042] Different from Example 1, in the mixed solution, the mass ratio of the boron source, the water and the carbon source is 6:60:2.

[0043] Example 4:

[0044] Ammonium persulfate was added to the boron-doped biochar prepared in Example 1 to prepare a catalytic system; the mass of the boron-doped biochar was 0.0125 g, and the mass of the ammonium persulfate was 0.114 g (ie, a molar weight of 0.5 mmol).

[0045] Example 5:

[0046] Ammonium persulfate was added to the boron-doped biochar prepared in Example 1 to prepare a catalytic system; the mass of the boron-doped biochar was 0.0250 g; the mass of the ammonium persulfate was 0.114 g (ie, the molar weight was 0.5 mmol).

[0047] Example 6:

[0048] The difference from Example 5 is that the mass of the ammonium persulfate is 0.0228 g (ie, the molar weight is 0.1 mmol).

[0049] Example 7:

[0050] The difference from Example 5 is that the mass of the ammonium persulfate is 0.228 g (ie, the molar weight is 1.0 mmol).

[0051] Example 8:

[0052] The difference from Example 5 is that the mass of the ammonium persulfate is 0.456 g (ie, the molar weight is 2.0 mmol).

[0053] Comparative Example 1:

[0054] The difference from Example 1 is that the amount of the boron source used is zero, that is, non-boron-doped biochar is prepared.

[0055] Comparative Example 2:

[0056] The difference from Example 1 is that the calcination temperature used in the calcination treatment is 500°C.

[0057] Comparative Example 3:

[0058] The difference from Example 1 is that the calcination temperature used in the calcination treatment is 700°C.

[0059] Comparative Example 4:

[0060] Ammonium persulfate was added to the boron-doped biochar prepared in Example 1 to prepare a catalytic system; the mass of the boron-doped biochar was 0.0063 g, and the mass of the ammonium persulfate was 0.114 g (ie, a molar weight of 0.5 mmol).

[0061] The boron-doped biochar prepared by embodiment 1 and the unboron-doped biochar prepared by comparative example 1 all weigh 12.5mg and add respectively in the dichloroquine acid aqueous solution that 50mL concentration is 10mg / L to form two groups of adsorption systems, carry out adsorption experiment respectively.After adsorption equilibrium, measure the residual dichloroquine acid concentration in the dichloroquine acid aqueous solution; Subsequently, in every group of adsorption system, add the ammonium persulfate solution (being abbreviated as APS) that 125uL concentration is 200mM, namely add 0.025mmol ammonium persulfate to form degradation system, react for 30 minutes to wait for degradation equilibrium and measure the residual dichloroquine acid concentration in the dichloroquine acid aqueous solution.According to initial dichloroquine acid concentration and residual dichloroquine acid concentration, calculate the clearance of dichloroquine acid in adsorption system and degradation system, result is as table 1.

[0062] Table 1 Removal rates of quinclorac by boron-doped biochar and non-boron-doped biochar under different systems

[0063]

[0064] As shown in Table 1, the adsorption rate and degradation rate of dichloroquinoline by the unboron-doped biochar prepared in Comparative Example 1 are both lower than 10%. In comparison, the adsorption rate and degradation rate of dichloroquinoline by the boron-doped biochar prepared in Example 1 are greatly improved, with the degradation rate reaching 88.7%, indicating that boron doping can significantly improve the physical and chemical properties of the biochar surface and improve its adsorption and catalytic degradation performance.

[0065] The non-boron-doped biochar prepared in Comparative Example 1 and the boron-doped biochar prepared in Example 1 and Comparative Examples 2-3 at different calcination temperatures were sampled and analyzed by scanning electron microscopy. The results are as follows: Figure 1 shown. Figure 1 (a) is the 600℃ biochar without boron doping, namely TBC-600; Figure 1 (b)-(d) are respectively 500℃ biochar, 600℃ biochar and 700℃ biochar with a mass ratio of boric acid to tea residue of 4:2 (i.e. 2:1), i.e. 2-BTC-500, 2-BTC-600 and 2-BTC-700. Figure 1 It is known that boron doping can form carbon microspheres on the surface of biochar, thereby increasing the specific surface area of ​​biochar. As the temperature rises to 700℃, the carbon microspheres agglomerate, which may reduce the specific surface area of ​​the material and lead to a decrease in the degradation rate of dichloroquinoline.

[0066] 12.5 mg of each boron-doped biochar prepared at different calcination temperatures in Example 1 and Comparative Examples 2-3 was weighed and added to 50 mL of a 10 mg / L aqueous solution of quinclorac. Then, 125 μL of a 200 mM APS solution (i.e., 0.025 mmol APS) was added. The mixture was reacted for 30 minutes until degradation equilibrium was reached, and the remaining quinclorac concentration in the aqueous solution was measured. The degradation rate of quinclorac by the boron-doped biochar prepared at different calcination temperatures was calculated based on the initial and remaining quinclorac concentrations. The results are shown in Table 2.

[0067] Table 2 Degradation rate of quinclorac by boron-doped biochar prepared at different calcination temperatures

[0068]

[0069] As shown in Table 2, in the presence of APS, the boron-doped biochar prepared at 600°C in Example 1 of the present invention exhibited the highest degradation rate of quinclorac compared to the boron-doped biochar prepared at 500°C and 700°C. This is because the boron-doped biochar prepared at 600°C has a higher specific surface area and abundant pore structure, which facilitates the adsorption of quinclorac, thereby improving the catalytic degradation rate of quinclorac.

[0070] 12.5 mg of each of the boron-doped biochars prepared in Examples 1-3 at different boron source dosages and the unboron-doped biochar prepared in Comparative Example 1 were weighed and added to 50 mL of a 10 mg / L aqueous solution of quinclorac. Then, 125 μL of a 200 mM APS solution (i.e., 0.025 mmol APS) was added. The mixture was reacted for 30 minutes until degradation equilibrium was reached, and the remaining quinclorac concentration in the aqueous solution was measured. The removal efficiency of quinclorac by the boron-doped biochars prepared at different boron source dosages was calculated based on the initial quinclorac concentration and the remaining quinclorac concentration. The results are shown in Table 3.

[0071] Table 3 Effect of different amounts of boron source biochar on the removal of dichloroquinoline

[0072]

[0073] As shown in Table 3, in the presence of APS, the degradation of dichloroquine by biochar without boron addition was less than 10%, while the degradation of dichloroquine by biochar after boron addition was between 79.6% and 88.7%, indicating that boron addition can effectively improve the catalytic performance of biochar, and the best removal effect of dichloroquine is achieved when the mass ratio of boric acid to tea residue is 4:2 (i.e., 2:1).

[0074] The catalytic systems prepared in Examples 4-5 and Comparative Example 4 were added to 50 mL of a 10 mg / L (initial concentration c0) aqueous solution of quinclorac, and samples were taken after reaction times t of 2 min, 5 min, 10 min, 20 min, and 30 min, and the residual quinclorac concentration c was determined by high performance liquid chromatography. t , calculate the degradation rate, and calculate the first-order kinetic rate constant k according to the following formula (W): obs The curve of the change of quinclorac concentration at different reaction times t with different amounts of boron-doped biochar in the catalytic system is shown in Figure 2. Figure 2 As shown. The degradation rate and first-order kinetic rate constant k of quinclorac by different amounts of boron-doped biochar in the catalytic system after the reaction time t is 30 min obs The values ​​are shown in Table 4.

[0075]

[0076] Table 4 Degradation rate and k of quinclorac at different dosages of boron-doped biochar in the catalytic system obs The impact of value

[0077] Grouping Comparative Example 4 Example 4 Example 5 Boron-doped biochar dosage (g) 0.0063 0.0125 0.0250 Degradation rate (%) 46.6 83.7 91.4 <![CDATA[K obs (min -1 )]]> 0.0324 0.0835 0.1147

[0078] As shown in Table 4, the degradation rate of quinclorac increases with the increase of the amount of boron-doped biochar within the reaction time t of 30 min. When the amount of boron-doped biochar is 0.0250 g, the degradation rate and efficiency of quinclorac in this system are the highest. It is expected that when the amount of boron-doped biochar increases to a certain extent, quinclorac can be completely degraded.

[0079] The catalytic systems prepared in Examples 5-8 were added to 50 mL of a 10 mg / L (initial concentration c0) aqueous solution of quinclorac, and samples were taken after reaction times t of 2 min, 5 min, 10 min, 20 min, and 30 min, and the residual quinclorac concentration c was determined by high performance liquid chromatography. t , calculate the degradation rate, and calculate k according to the following formula (W) obs The curve of the change of quinclorac concentration with different amounts of ammonium persulfate in the catalytic system at different reaction times t is as follows: Figure 3 As shown. The degradation rate and k of dichloroquinoline acid with different amounts of ammonium persulfate in the catalytic system after the reaction time t is 30min obs The values ​​are shown in Table 5.

[0080] Table 5 Degradation rate and k of quinclorac at different dosages of ammonium persulfate in the catalytic system obs The impact of value

[0081] Grouping Example 6 Example 5 Example 7 Example 8 APS (mmol) 0.1 0.5 1.0 2.0 Degradation rate% 79.2 91.4 87.1 85.4 <![CDATA[K obs (min -1 )]]> 0.0515 0.1147 0.0801 0.093

[0082] As shown in Table 5, as the amount of ammonium persulfate APS increases in the catalytic system, its degradation rate and k obs The values ​​did not increase linearly, but showed a trend of increasing first and then decreasing. Among them, when the APS dosage was 0.5mmol, the degradation rate of dichloroquinoline and k obs The value reaches the maximum value; when the amount of APS is greater than 0.5mmol, the degradation rate decreases instead. This is because there are too many free radicals (such as SO4 ·- and ·OH), resulting in the mutual reaction between free radicals, as shown in reaction formula (1)-(2), which reduces the free radical content in the degradation system and leads to a slight decrease in the degradation effect.

[0083] SO4 ·- +SO4 ·- →S2O8 2- (1)

[0084] ·OH+·OH→H2O2 (2)

[0085] Five groups of catalytic system samples were prepared in parallel with Example 4 and added to five groups of dichloroquine acid aqueous solutions of different pH values ​​as shown in Table 6, wherein the concentration of each group of dichloroquine acid aqueous solutions was 10 mg / L and the volume was 50 mL. Samples were taken after reaction times t of 2 min, 5 min, 10 min, 20 min, and 30 min, and the residual dichloroquine acid concentration was determined by high performance liquid chromatography. The degradation rate was calculated. The results are shown in Table 6. Figure 4 The degradation rates of the dichloroquinoline aqueous solutions at different pH values ​​after a reaction time of 30 min are shown in Table 6.

[0086] Table 6 Degradation rate of quinclorac under different pH conditions

[0087] pH 2.38 4.55 7.34 10.30 11.60 Degradation rate (%) 76.8 83.8 86.4 85.2 40.0

[0088] As shown in Table 6, under different pH conditions, the degradation rates of the four catalytic systems prepared in parallel by Example 4 for dichloroquine are all very high at a larger pH range (2.38-10.30), which are above 76.8%. However, when the pH is 11.60, the degradation rate drops to 40.0%, which may be because the isoelectric point of the boron-doped biochar is 10.48. When the pH value of the system is less than 10.48, the surface of the boron-doped biochar is positively charged, and persulfate and dichloroquine are ionized into anions under this acidity condition, resulting in a large electrostatic attraction between the boron-doped biochar and them, thereby effectively catalyzing the degradation of dichloroquine by APS. However, when the pH of the system increases to 11.60, the surface of the boron-doped biochar is negatively charged, resulting in a large electrostatic repulsion between it and persulfate and dichloroquine, resulting in a significant decrease in the degradation rate of dichloroquine. Therefore, the suitable pH range for the catalytic degradation of dichloroquine by boron-doped biochar on APS is 2.38-10.30.

[0089] Figure 5 The XPS spectra of boron-doped biochar before and after reaction in Example 1 in Table 1 are shown. Figure 5 It is known that after the reaction of boron-doped biochar, the content of certain oxygen-containing functional groups, such as -COOH, -C=O, BCO2 and BC2O, decreases compared to before the reaction, indicating that these oxygen-containing functional groups may participate in the reaction. Specifically, these oxygen-containing functional groups have electron-rich oxygen groups with conjugated π systems, which can serve as active sites to promote the transfer of electrons from boron-doped biochar to APS, causing APS to produce sulfate radicals SO4 ·- The sulfate radical then reacts with other substances to produce other active species. The specific reaction process is as follows (BTC-C=O and BTC-OH represent the carbonyl and hydroxyl functional groups on the boron-doped biochar, respectively):

[0090] S2O8 2- +e - →SO4 ·-+SO4 2-

[0091] SO4 ·- +H2O→SO4 2- +·OH+H +

[0092] BTC-C=O+S2O8 2- →SO4 ·- +SO4 2- +BTC=O +

[0093] BTC-OH+S2O8 2- →SO4 ·- +SO4 2- +BTC-O·+H +

[0094] BTC-O·+S2O8 2- +2OH - →BTC=O+2SO4 2- + 1 O2+2H2O

[0095]

[0096]

[0097] According to the method reported in the literature (Science of the Total Environment 856(2023)158917), 5,5-dimethyl-pyrroline-nitrogen oxide (DMPO) was used as SO4 ·- , OH and O2 ·- Tetramethylpiperidone (TEMP) was used as a free radical scavenger. 1 O2 non-radical scavengers, the presence of each active substance in the catalytic system prepared in Example 4 was determined by the electron paramagnetic resonance technique (EPR) through the hyperfine coupling interaction between these active substances and DMPO and TEMP. The measurement results are as follows Figure 6 shown.

[0098] Depend on Figure 6 It is known that in the catalytic system prepared in Example 4, the boron-doped biochar catalyzes the SO4 produced by APS. ·- , OH, O2 ·- and 1The O2 signal increases with time, indicating that the content of the four active substances in the catalytic reaction system increases with time, which plays a role in the degradation of dichloroquine. Dichloroquine reacts with the active substances to form intermediates, which are finally decomposed into carbon dioxide, water and other small molecular products. The possible degradation pathways are as follows Figure 7 See Figure 7 There are two main degradation pathways and 11 degradation products of quinclorac (abbreviated as QC). Degradation pathway Ⅰ (i.e. Pathway Ⅰ): SO4 ·- , ·OH, and 1 O2 attacks QC, thereby decarboxylating and opening the pyridine ring to generate product E, which then undergoes decarboxylation, alkyl olefination, and rearrangement to generate product F, and then SO4 ·- Extracting an electron from the oxygen in the carboxyl group, the resulting carboxyl radical releases carbon dioxide and an alkyl radical, thereby decarboxylating. 1 O2 generates product G through electrophilic addition and electron abstraction, and finally product G is mineralized to produce carbon dioxide, water and other small molecular products; degradation pathway II (i.e., Pathway II): ·OH attacks the QC quinoline ring through substitution reaction to produce product A, and then product A reacts with active substances and undergoes a series of chemical reactions such as dechlorination, hydroxylation, ring opening, dealkylation and oxidation to produce products B, C, D, I, J and K. Subsequently, part of product I generates product G, and finally products G, I and K are mineralized to produce carbon dioxide, water and other small molecular products.

[0099] Twenty tobacco seedlings of uniform growth were transplanted into 20 plastic pots containing 250 g of soil to form 20 potted tobacco seedlings. The 20 potted tobacco seedlings were then incubated in a constant temperature incubator maintained at 25°C, 75% relative humidity, and a 16 / 8 hour cycle (16 represents 16 hours of light exposure and 8 represents 8 hours of no light). After the seedlings were grown for 10 days and survived, the 20 pots were divided into four groups (five replicates each) and labeled as the T1 experimental group, the T2 experimental group, the T3 experimental group, and the CK experimental group. 2 groups of catalyst system samples are prepared in parallel in embodiment 5, wherein 1 group of catalyst system samples is added to 50mL in the water not containing quinclorac, is labeled as T1 experimental group and uses watering water;Another 1 group of catalyst system samples is added to 50mL in the water (containing quinclorac 0.5mg / L) containing quinclorac, is labeled as T2 experimental group and uses watering water;Get 50mL of water (containing quinclorac 0.5mg / L) containing quinclorac and is labeled as T3 experimental group and uses watering water;Get 50mL of water (containing quinclorac 0.5mg / L) and is labeled as CK experimental group and uses watering water.The watering water of T1 experimental group, T2 experimental group, T3 experimental group and CK experimental group is respectively arranged 20 repetitions by identical configuration conditions, and every pot of tobacco seedlings in corresponding group repeats to irrigate 4 times, and every adjacent two irrigation times all equal. Ten days later, the agronomic traits of tobacco seedlings were measured (the fourth leaf from the top, leaf area = leaf length × leaf width × 0.635, where 0.635 is the common leaf area coefficient for flue-cured tobacco). The relevant agronomic traits are shown in Table 7 (in Table 7, each value is the measurement mean ± standard deviation, and different lowercase letters in the same column of data indicate significant differences at the P < 0.05 level).

[0100] Table 7 Agronomic traits of tobacco seedlings under different treatments

[0101] Grouping Leaf length (cm) Leaf width (cm) <![CDATA[Leaf area (cm 2 )]]> Plant height (cm) Number of blades CK 13.66±0.9b 7.1±0.41a 61.73±7.08b 6.6±1.07a 12.6±1.52a T1 17.34±1.7a 7.98±0.94a 88.65±19.41a 7.28±1.1a 11.6±1.67ab T2 16.56±1.97a 8.1±0.65a 85.5±14.47a 5.66±1.78ab 12.2±1.3ab T3 11.12±1.26c 3.92±0.87b 28.03±8.73c 4.28±0.83b 10.2±1.92b

[0102] From Table 7 and Figure 8 It can be seen that compared with the CK experimental group, the tobacco seedlings irrigated with the T3 experimental group grew significantly worse than those in the CK experimental group, and showed phytotoxicity such as leaf curling and growth inhibition; the leaf length and leaf width of the T1 and T2 experimental groups increased, and the leaf area increased by about 27 cm and 10 cm, respectively, compared with the tobacco seedlings in the CK experimental group. 2 and 24cm 2 , indicating that the T1 and T2 experimental groups containing the catalytic degradation system not only alleviated quinclorac phytotoxicity but also promoted the growth and development of tobacco seedlings. This is mainly because the nutrients contained in the catalytic system, such as boron, nitrogen, and organic matter, can provide nutritional elements for tobacco seedling growth. It can be seen that the catalytic system of the present invention can not only effectively degrade quinclorac, alleviate phytotoxicity in tobacco seedlings, but also provide nutrients for tobacco seedling growth.

[0103] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An application of a boron-doped biochar catalytic system in catalytic degradation of quinclorac, characterized in that: The catalytic system comprises adding persulfate to boron-doped biochar; the mass ratio of the boron-doped biochar to the persulfate is 0.01-0.025:0.0228-0.456; the persulfate comprises ammonium persulfate; The method for preparing boron-doped biochar comprises adding a boron source to water, heating and dissolving the boron source, then adding a carbon source, and stirring the mixture to obtain a mixed solution; heating and evaporating the mixed solution under stirring conditions to obtain a concentrate; and drying and calcining the concentrate to obtain boron-doped biochar that promotes tobacco growth. In the mixed solution, the mass ratio of the boron source, the water and the carbon source is 2-6:40-60:2-10.

2. The use of the boron-doped biochar catalytic system according to claim 1 in catalytic degradation of quinclorac, characterized in that: The boron source includes at least one of boric acid, borax, sodium borate and boron oxide.

3. The use of the boron-doped biochar catalytic system according to claim 1 in catalytic degradation of quinclorac, characterized in that: The carbon source comprises at least one of waste tea residue, fruit peel, fruit shell, tobacco straw and reed straw.

4. The use of the boron-doped biochar catalytic system according to claim 1 in catalytic degradation of quinclorac, characterized in that: The heating temperature used for the heating dissolution is 50°C-90°C; the heating temperature used for the heating evaporation is 50°C-90°C.

5. The use of the boron-doped biochar catalytic system according to claim 1 in catalytic degradation of quinclorac, characterized in that: The drying temperature used in the drying process is 60° C.-90° C., and the drying time is 12 h-24 h.

6. Use of the boron-doped biochar catalytic system according to any one of claims 1 to 5 in catalytic degradation of quinclorac, characterized in that: The calcination treatment adopts a calcination temperature of 550°C-650°C and a calcination time of 2h-4h; the heating rate adopted before heating to the calcination temperature is 5-10°C / min; the cooling rate adopted after the calcination is completed is 10-15°C / min; inert gas is introduced during the calcination process, and the flow rate of the inert gas is controlled to be 200-800mL / min.

7. Use of the boron-doped biochar catalytic system according to claim 6 in catalytic degradation of quinclorac, characterized in that: After the calcination treatment, a post-treatment is also included, and the post-treatment includes washing the boron-doped biochar with alcohol and water.

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