Adsorption-oxidation difunctional boron-doped porous biochar material as well as preparation method and application thereof

Abstract

The invention discloses an adsorption-oxidation difunctional boron-doped porous biochar material and a preparation method and application thereof, the preparation method comprises the following steps: mixing alfalfa, sodium bicarbonate, boric acid and water, evaporating and pyrolyzing to obtain the boron-doped porous biochar material. The adsorption-oxidation dual-function boron-doped porous biochar material has the advantages of large specific surface area, developed multi-stage pore structure, rich oxygen-containing functional groups, good surface affinity, high-reaction-activity boron-doped species BC3 and the like, so that the adsorption performance and the catalytic performance are excellent; when being applied to a persulfate advanced oxidation technology, the catalyst can realize efficient removal of sulfonamide antibiotics mediated by a non-free radical way, has the advantages of strong adsorption capacity, high catalytic activity, good recycling property and the like, and shows good practical application potential.

Description

Technical Field

[0001] The present invention belongs to the field of biochar materials and water treatment, and in particular relates to an adsorption-oxidation dual-functional boron-doped porous biochar material and a preparation method and application thereof. Background Art

[0002] Antibiotics are one of the most important discoveries in medicine. Since the discovery of penicillin in 1928, countless new antibiotics have been developed and widely used in human medicine, livestock, poultry, and aquaculture. However, due to widespread and ongoing global overuse, improper discharge and disposal, and the inherent biodegradability of antibiotics, antibiotic residues in the environment continue to rise, and their presence has been detected in aquatic environments worldwide. Environmental antibiotic residues can disrupt the structure and function of certain microbial populations, thereby affecting ecological functions such as nitrogen transformation, nutrient cycling, and organic matter degradation, and even leading to ecological imbalance. Furthermore, long-term antibiotic retention can accelerate the development of antibiotic-resistant bacteria and antibiotic resistance genes in the surrounding environment, leading to increased resistance to antimicrobial drugs and posing a significant threat to the ecological environment. In recent years, sulfonamide antibiotics, particularly sulfamethoxazole (SMX), have been frequently detected in water bodies worldwide, posing a serious ecological risk. However, due to its stable molecular structure and low biodegradability, SMX has proven difficult to effectively remove using traditional wastewater treatment methods and processes involving biological treatment.

[0003] In recent years, persulfate-based advanced oxidation processes (PS-AOPs) have been recognized as promising green and efficient technologies for antibiotic wastewater remediation due to their excellent oxidation capacity, good environmental compatibility, and ease of operation. Among these technologies, biochar-activated persulfate technology has been widely studied and applied due to its environmental friendliness, economic feasibility, simplicity, and high efficiency. Numerous studies have demonstrated that biochar-activated persulfate technology can effectively remove pollutants such as heavy metals, polycyclic aromatic hydrocarbons, antibiotics, polychlorinated biphenyls, and herbicides from the environment, showing great potential in soil and water environmental remediation, including soil improvement, groundwater remediation, and wastewater treatment. However, existing biochar materials, particularly for the treatment of sulfonamide antibiotics, suffer from low antibiotic adsorption, low adsorption rates, poor removal efficiency, and slow degradation rates. Therefore, there is an urgent need to develop a boron-doped porous biochar material with strong adsorption capacity, high catalytic activity, and good recyclability for the rapid and complete removal of sulfonamide antibiotics. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an adsorption-oxidation dual-functional boron-doped porous biochar material with strong adsorption capacity, high catalytic activity and good recyclability, as well as a preparation method and application thereof.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0006] A method for preparing an adsorption-oxidation dual-functional boron-doped porous biochar material comprises the following steps: S1. Mixing alfalfa, sodium bicarbonate, boric acid, and water, and heating until the water is completely evaporated to obtain a mixture; the mass ratio of the alfalfa, sodium bicarbonate, and boric acid is 1:1:0.2-0.75; S2. Pyrolyzing the mixture obtained in step S1 at a temperature greater than 650° C. to obtain an adsorption-oxidation dual-functional boron-doped porous biochar material.

[0007] The above preparation method is further improved, in step S1, the mass ratio of alfalfa, sodium bicarbonate and boric acid is 1:1:0.2-0.3.

[0008] The above preparation method is further improved in that in step S2, the pyrolysis temperature is 700°C to 900°C.

[0009] The above preparation method is further improved. In step S1, the heating temperature is 80° C. to 90° C., and the heating is performed under stirring conditions. The alfalfa is further processed as follows before use: washing, drying, and crushing the alfalfa.

[0010] The above preparation method is further improved. In step S2, the pyrolysis is carried out under a nitrogen atmosphere, the heating rate during the pyrolysis process is 5°C / min to 10°C / min, and the pyrolysis time is 2h to 4h; after the pyrolysis, the following treatment is also included: washing and drying the pyrolysis product, and the drying temperature is 50°C to 70°C.

[0011] As a general technical concept, the present invention also provides an adsorption-oxidation dual-functional boron-doped porous biochar material prepared by the above-mentioned preparation method.

[0012] The above-mentioned adsorption-oxidation dual-functional boron-doped porous biochar material is further improved in that the adsorption-oxidation dual-functional boron-doped porous biochar material has a microporous and mesoporous structure.

[0013] As a general technical concept, the present invention also provides an application of the above-mentioned adsorption-oxidation dual-functional boron-doped porous biochar material in treating antibiotic wastewater.

[0014] The above application is further improved, comprising the following steps: mixing the adsorption-oxidation dual-functional boron-doped porous biochar material with antibiotic wastewater, adding persulfate, and performing a catalytic degradation reaction to achieve degradation of antibiotics in the water. The above application is further improved, wherein the mass ratio of the adsorption-oxidation bifunctional boron-doped porous biochar material to the antibiotic in the antibiotic wastewater is 0.5 to 10:1, the amount of persulfate added is 0.25 mmol to 1 mmol of persulfate per liter of antibiotic wastewater, the initial concentration of the antibiotic in the antibiotic wastewater is 10 mg / L to 50 mg / L, the initial pH value of the antibiotic wastewater is 3 to 9, the antibiotic in the antibiotic wastewater is a sulfonamide antibiotic, the sulfonamide antibiotic is sulfamethoxazole, the persulfate is sodium peroxydisulfate, the time of the catalytic degradation reaction is ≥20 min, the catalytic degradation reaction is carried out under stirring conditions, and the stirring speed is 300 r / min to 500 r / min.

[0015] Compared with the prior art, the advantages of the present invention are: (1) The present invention provides a method for preparing an adsorption-oxidation dual-functional boron-doped porous biochar material, using alfalfa as a raw material, sodium bicarbonate and boric acid as modifiers, and limiting the mass ratio of alfalfa, sodium bicarbonate, and boric acid to 1:1:0.2-0.75. The adsorption-oxidation dual-functional boron-doped porous biochar material is prepared by a simple heating-pyrolysis method. The preparation method of the present invention, on the one hand, sodium bicarbonate and boric acid decompose and release a large amount of gas during the pyrolysis process. Combined with the expansion of water vapor inside the alfalfa, a multi-level pore structure with coexisting micropores and mesopores is formed within the biochar material. The micropores provide sufficient adsorption space, and the mesopores facilitate the transmission and diffusion of organic macromolecules, thereby providing sufficient adsorption sites and reaction sites. On the other hand, the boron doping not only increases the content of highly reactive C=O and π-π* in the biochar material, but also forms a graphite-like structure BC3, which has superior electron transfer ability and provides favorable reaction conditions for persulfate activation. More importantly, by limiting the mass ratio of alfalfa, sodium bicarbonate, and boric acid to 1:1:0.2-0.75, the biochar material has a higher B content and O content, which is more conducive to the formation of various boron-doped species and oxygen-containing functional groups, thereby improving the redox capacity of the biochar and giving the biochar material high catalytic activity. The preparation method of the present invention has the advantages of mild reaction conditions, simple process flow, environmental protection, low energy consumption, and low cost.

[0016] (2) The preparation method of the present invention optimizes the mass ratio of alfalfa, sodium bicarbonate, and boric acid to 1:1:0.2-0.3, thereby obtaining an adsorption-oxidation bifunctional boron-doped porous biochar material with the best performance in terms of adsorption capacity, catalytic activity, and recyclability. If the amount of boric acid used is too small, it is not conducive to the introduction of heteroatoms; if the amount of boric acid used is too large, it will clog the pores and destroy the carbon skeleton framework, thereby affecting the performance of the catalyst. At the same time, it will further expand the pores and cause a large-scale collapse of the pore structure, resulting in a significant decrease in the adsorption capacity of the carbon material.

[0017] (3) The present invention also provides an adsorption-oxidation dual-functional boron-doped porous biochar material, which has the advantages of large specific surface area, developed multi-level pore structure, rich oxygen-containing functional groups, good surface affinity and highly reactive boron-doped species BC3, thereby showing excellent adsorption and catalytic properties; when it is applied to persulfate advanced oxidation technology, it can achieve efficient removal of sulfonamide antibiotics mediated by non-free radical pathways, and has the advantages of strong adsorption capacity, high catalytic activity, good recyclability, etc., showing good practical application potential.

[0018] (4) The present invention also provides an application of an adsorption-oxidation bifunctional boron-doped porous biochar material in the treatment of antibiotic wastewater. The adsorption-oxidation bifunctional boron-doped porous biochar material is used to catalyze the activation of persulfate, which can achieve rapid removal of antibiotics in water bodies and has good resistance to interfering ions in water bodies. It has the advantages of simple operation, high treatment efficiency, controllable risk of secondary environmental pollution, and wide adaptability to the environment, and has good practical application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 These are scanning electron microscope images of the original biochar (BC), porous biochar (PC), and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) prepared in Example 1 of the present invention.

[0020] Figure 2 This is a pore size distribution curve of the original biochar (BC), porous biochar (PC) and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) prepared in Example 1 of the present invention.

[0021] Figure 3 These are Raman graphs of the original biochar (BC), porous biochar (PC), and the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) before and after use prepared in Example 1 of the present invention.

[0022] Figure 4XPS graphs of C 1s, O 1s, and B 1s of the porous biochar (PC) prepared in Example 1 of the present invention and the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) before and after use.

[0023] Figure 5 This is a diagram showing the degradation effects of sulfamethoxazole by activating persulfate with original biochar (BC), porous biochar (PC), and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) in Example 2 of the present invention.

[0024] Figure 6 This is a graph showing the degradation reaction rates of sulfamethoxazole by persulfate activation using original biochar (BC), porous biochar (PC), and adsorption-oxidation bifunctional boron-doped porous biochar material (BPC-0.25) in Example 2 of the present invention.

[0025] Figure 7 This is a diagram showing the degradation effect of sulfamethoxazole by activating persulfate with different adsorption-oxidation dual-functional boron-doped porous biochar materials (BPC-0.25, BPC-0.5, and BPC-0.75) in Example 3 of the present invention.

[0026] Figure 8 Graph showing the linear correlation between the adsorption rate and oxidation rate of the original biochar (BC), porous biochar (PC), and adsorption-oxidation dual-functional boron-doped porous biochar materials (BPC-0.25, BPC-0.5, and BPC-0.75) in Example 3 of the present invention.

[0027] Figure 9 This is a diagram showing the degradation effect of sulfamethoxazole by activating persulfate at different pH values ​​using the adsorption-oxidation dual-functional boron-doped porous biochar (BPC-0.25) in Example 4 of the present invention.

[0028] Figure 10 This is a diagram showing the degradation effect of sulfamethoxazole by activating persulfate in the presence of different interferents using the adsorption-oxidation dual-functional boron-doped porous biochar (BPC-0.25) in Example 5 of the present invention. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but the scope of protection of the present invention is not limited thereby. The materials and instruments used in the following examples are all commercially available.

[0030] Example 1: A method for preparing an adsorption-oxidation dual-functional boron-doped porous biochar material of the present invention comprises the following steps: S1. Wash the purchased alfalfa with deionized water to remove impurities, place it in a constant temperature drying oven at 60°C for 24 hours, and grind and sieve the dried alfalfa (100 mesh, <0.15 mm) to obtain alfalfa powder of uniform size.

[0031] S2. Mix 1 g of alfalfa powder, 1 g of sodium bicarbonate, 0.25 g of boric acid, and 30 mL of deionized water. Heat in a water bath at 80° C. with stirring until the solution is completely evaporated (evaporated to dryness) to obtain a mixture.

[0032] S3. The mixture obtained in step S2 was transferred to a tube furnace, heated to 800°C at a heating rate of 5°C / min using nitrogen as a protective gas, and pyrolyzed for 3 h. After the sample was naturally cooled, the pyrolysis product was washed with ultrapure water and anhydrous ethanol several times to remove impurities. Finally, it was dried at 60°C overnight to obtain an adsorption-oxidation dual-functional boron-doped porous biochar material, named BPC-0.25.

[0033] In this example, different adsorption-oxidation bifunctional boron-doped porous biochar materials were also prepared. Their preparation methods were basically the same as the preparation method of the adsorption-oxidation bifunctional boron-doped porous biochar material (BPC-0.25), with the only difference being that in step S2, the amounts of boric acid used were 0.5 g and 0.75 g, respectively; the corresponding adsorption-oxidation bifunctional boron-doped porous biochar materials were named BPC-0.5 and BPC-0.75, respectively.

[0034] In addition, undoped raw biochar was also prepared. Its preparation method was basically the same as that of the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25), with the only difference being that sodium bicarbonate and boric acid were not added in step S2; the raw biochar obtained was named BC.

[0035] In addition, porous biochar was also prepared. Its preparation method was basically the same as that of the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25), with the only difference being that boric acid was not added in step S2; the porous biochar obtained was named PC.

[0036] Figure 1 These are scanning electron microscope images of the original biochar (BC), porous biochar (PC), and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) prepared in Example 1 of the present invention. Figure 1 In the figure, (a) is BC, (b) is PC, and (c) is BPC-0.25. Figure 1 As shown in (a), the undoped raw biochar (BC) presents an irregular block structure with a relatively smooth surface and almost no wrinkles or holes. Figure 1As shown in (b), porous biochar (PC) has interconnected pores of varying sizes that are distributed in an orderly and dense manner on its surface, forming an extremely developed honeycomb pore structure. Figure 1 As shown in (c), the adsorption-oxidation bifunctional boron-doped porous biochar (BPC-0.25) exhibits partial inward pore collapse, while the majority of the pore structure remains preserved. This results in a roughened surface, thinned pore walls, disordered pores, and more wrinkles. This is due to two factors: first, the pores expand during pyrolysis of boric acid, further increasing pore size and leading to unstable pore structures, which gradually break or collapse. Second, the introduction of boron destroys portions of the carbon skeleton, causing some structural collapse. This demonstrates that the adsorption-oxidation bifunctional boron-doped porous biochar (BPC-0.25) of the present invention possesses a well-developed pore structure, providing ample adsorption and reaction sites.

[0037] Figure 2 This is a pore size distribution curve of the original biochar (BC), porous biochar (PC) and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) prepared in Example 1 of the present invention. Figure 2 In the figure, N2 adsorption / desorption isotherms are inserted. Specific surface area and pore characteristics are key parameters for evaluating the adsorption performance of catalysts, which can be measured by N2 adsorption-desorption isotherm tests. Figure 2 As shown, compared to PC, BPC-0.25 has a more complex multiscale porous structure, forming a hierarchical porous structure with both micropores and mesopores. Furthermore, the N2 adsorption-desorption isotherm fitting results also show that the BPC-0.25 isotherm coincides with type IV, indicating that the pore morphology of BPC-0.25 is a coexistence of micropores and mesopores. Because micropores provide ample adsorption space and mesopores facilitate the transport and diffusion of organic macromolecules, the hierarchical porous structure of BPC-0.25 is more conducive to adsorption and catalytic reactions.

[0038] Figure 3 The Raman graphs of the original biochar (BC), porous biochar (PC), and the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) prepared in Example 1 of the present invention before and after use are shown. Figure 3 It can be seen that the Raman spectrum of carbon materials forms two characteristic peaks, which are located at 1355 cm -1 Place, representing disordered sp 3 The D band peaks of carbon and defects, as well as the peak at 1580 cm -1 At, represents the ordered sp 2 The G band peak of carbon (i.e. the degree of graphitization). The peak intensity ratio of the D band and the G band (I D / I G) can be used to characterize the degree of graphitization of the material, I D / I G The larger the ratio, the more defects the carbon material has and the lower the degree of graphitization. Figure 3 As shown, compared with BC, PC has a higher I D / I G The ratio decreased significantly, indicating that PC has a higher degree of graphitization and better conductivity; compared with PC, BPC-0.25, I D / I G The ratio is slightly improved, which indicates that B doping retains most of the carbon skeleton structure of PC and only slightly increases the degree of defects. It is worth noting that the I D / I G The ratio is still greater than 1.0, which indicates that there are still certain defect structures in the carbon material, and the defect structure of the carbon material is an important active site, which shows that the adsorption-oxidation bifunctional boron-doped porous biochar (BPC-0.25) can activate persulfate to produce various reactive oxygen species through free radical or non-free radical pathways.

[0039] Figure 4 The XPS graphs of C 1s, O 1s and B 1s of the porous biochar (PC) prepared in Example 1 of the present invention and the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) before and after use. Figure 4 It can be seen that compared with PC, the content of CC bonds in BPC-0.25 decreased significantly, while the content of CO / COB bonds increased. More importantly, it was also observed that the contents of C=O and π-π* in BPC-0.25 increased. C=O with highly active lone pair electrons and π-π* with electron acceptance and donation capabilities can improve the catalytic activity of carbon materials. They can act as reaction sites or electron transfer media to activate persulfate to degrade pollutants. In addition, the peaks of BC3 (191.2 eV), BC2O (193.0 eV), and BCO2 (195.5 eV) were fitted into the B 1s XPS spectrum, further demonstrating the successful bonding of the boron atoms to the carbon skeleton. BC3 has the highest proportion, reaching 71.78%. Compared with BC2O and BCO2, BC3, with its graphite-like structure, has superior electron transfer ability. Furthermore, because the electronegativity of boron is weaker than that of carbon, positively charged active sites are formed in BC3, which is conducive to the adsorption of persulfate ions in the solution and the formation of a metastable carbon-PS* complex. This indicates that the adsorption-oxidation bifunctional boron-doped porous biochar of the present invention has higher surface reactivity than porous biochar (PC).

[0040] In addition, combined Figure 3 and Figure 4By comparing the Raman and XPS graphs of the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) before use and the adsorption-oxidation dual-functional boron-doped porous biochar material (used BPC-0.25) after use, it was proved that BPC-0.25 has excellent stability and reusability.

[0041] Example 2: An application of an adsorption-oxidation bifunctional boron-doped porous biochar material in treating antibiotic wastewater, specifically using the adsorption-oxidation bifunctional boron-doped porous biochar material to activate persulfate to degrade sulfamethoxazole in water, comprising the following steps: Take three 150 mL beakers, add 100 ml of a 10 mg / L, pH 4.75 sulfamethoxazole solution, and then add 10 mg each of the original biochar (BC), porous biochar (PC), and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) prepared in Example 1. Subsequently, 23.8 mg of sodium peroxydisulfate (PDS) was added to each beaker, mixed evenly, and the catalytic degradation reaction was carried out for 30 minutes under stirring at a speed of 450 r / min to complete the degradation of sulfamethoxazole in the water.

[0042] During the catalytic degradation process, samples were taken at 0 min, 5 min, 10 min, 20 min, and 30 min to determine the concentration of sulfamethoxazole in each beaker.

[0043] Adsorption groups (BC, PC, BPC-0.25): sodium persulfate was not added, and other conditions were the same.

[0044] Blank group (PDS): No catalyst was added, and other conditions were the same.

[0045] The specific surface area of ​​the adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) in Example 2 of the present invention was 841.10 m 2 / g, pore volume of 0.54 cm 3 / g, the average pore size is 9.44 nm, the adsorption capacity of sulfamethoxazole is 343.45 mg / g, and the adsorption rate is 0.050 min -1 The degradation rate of sulfamethoxazole was 0.233 min -1 .

[0046] Figure 5 The figure shows the degradation effect of sulfamethoxazole by activating persulfate with original biochar (BC), porous biochar (PC) and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) in Example 2 of the present invention. Figure 5As can be seen, PDS alone is barely capable of degrading sulfamethoxazole (SMX) due to its limited oxidation capacity. Similarly, unmodified BC and the BC / PDS system also failed to effectively degrade SMX, indicating the poor adsorption capacity and catalytic activity of the original biochar. Within 30 minutes, PC and PC / PDS achieved SMX removal efficiencies of 63.3% and 92.8%, respectively. Among all catalysts, BPC-0.25 performed best, adsorbing and removing 83% of SMX within 30 minutes. BPC-0.25 / PDS, synergistically oxidized with PDS, rapidly removed nearly 80% of SMX within 5 minutes and achieved complete degradation within 20 minutes.

[0047] Figure 6 The degradation reaction rate diagram of sulfamethoxazole degradation by persulfate activated by original biochar (BC), porous biochar (PC) and adsorption-oxidation dual-functional boron-doped porous biochar material (BPC-0.25) in Example 2 of the present invention is shown in FIG. Figure 6 As shown in the figure, when no PDS was added, the degradation reaction rate (k obs ) is 0.050 min -1 , respectively BC (k obs 0.002 min -1 ) 25 times, PC (k obs 0.031 min -1 ) is 1.6 times of that of BPC-0.25 / PDS; after adding PDS, the k obs 0.233 min -1 , respectively BC / PDS (k obs 0.010 min -1 ) 23 times, PC / PDS (k obs 0.082 min -1 ), which is 2.8 times that of BPC-0.25 / PDS. It can be seen that the removal efficiency of SMX by BPC-0.25 / PDS is effectively improved.

[0048] Combine Figure 5 and Figure 6 The results show that the adsorption and catalytic performance of the adsorption-oxidation bifunctional boron-doped porous biochar (BPC-0.25) are significantly enhanced compared to pristine biochar (BC) and porous biochar (PC). BPC-0.25 and PDS exhibit a positive synergistic effect, enabling the BPC-0.25 / PDS system to efficiently remove and mineralize sulfamethoxazole in water. This demonstrates that the adsorption-oxidation bifunctional boron-doped porous biochar of the present invention can achieve efficient and thorough degradation of antibiotics in water.

[0049] Example 3: The effects of different adsorption-oxidation bifunctional boron-doped porous biochars on the degradation of antibiotics were investigated. Specifically, the adsorption-oxidation bifunctional boron-doped porous biochar materials were used to activate persulfate to degrade sulfamethoxazole in water, including the following steps: Take three 150 mL beakers, add 100 ml of a 10 mg / L, pH 4.75 sulfamethoxazole solution, and then add 10 mg each of the adsorption-oxidation dual-functional boron-doped porous biochar materials (BPC-0.25, BPC-0.5, and BPC-0.75) prepared in Example 1. Subsequently, 23.8 mg of sodium peroxydisulfate (PDS) was added to each beaker, mixed evenly, and the catalytic degradation reaction was carried out at a stirring speed of 450 r / min for 30 minutes to complete the degradation of sulfamethoxazole in the water.

[0050] During the catalytic degradation process, samples were taken at 0 min, 5 min, 10 min, 20 min, and 30 min to determine the concentration of sulfamethoxazole in each beaker.

[0051] Adsorption groups (BPC-0.25, BPC-0.5, BPC-0.75): sodium persulfate was not added, and other conditions were the same.

[0052] Figure 7 This is a graph showing the degradation effect of sulfamethoxazole by activating persulfate with different adsorption-oxidation dual-functional boron-doped porous biochar materials (BPC-0.25, BPC-0.5, BPC-0.75) in Example 3 of the present invention. Figure 7As shown, compared to BPC-0.25, the adsorption and oxidation capacities of BPC-0.5 and BPC-0.75 for SMX decreased. Specifically, within 30 minutes, BPC-0.25 achieved an 83% SMX removal efficiency, while BPC-0.25 / PDS completely degraded SMX within 20 minutes. Meanwhile, within 30 minutes, the SMX removal efficiencies of BPC-0.5 and BPC-0.5 / PDS were 59.6% and 82.5%, respectively, while those of BPC-0.75 and BPC-0.75 / PDS were 29.4% and 91.1%, respectively. The significant decrease in the adsorption capacity of BPC-0.5 and BPC-0.75 is attributed to the fact that excessive boric acid can clog pores and destroy the carbon framework, thus affecting catalyst performance. Furthermore, boric acid has a pore-expanding effect during high-temperature pyrolysis. Excessive boric acid further expands the pores, leading to widespread pore collapse. In addition, the XPS test results also show that BPC-0.25 has a higher B content (2.82%) and O content (12.32%), which is more conducive to the formation of various boron-doped species and oxygen-containing functional groups, thereby further improving the redox capacity of the adsorption-oxidation dual-functional boron-doped porous biochar material.

[0053] Figure 8 The linear correlation diagram of the adsorption rate and oxidation rate of the original biochar (BC), porous biochar (PC) and adsorption-oxidation dual-functional boron-doped porous biochar materials (BPC-0.25, BPC-0.5, BPC-0.75) in Example 3 of the present invention is shown in FIG. Figure 8 As shown, based on the adsorption rate k obs and oxidation rate k obs The linear correlation between adsorption and oxidation in different catalyst systems was constructed, and the results showed that there was a good positive linear relationship between adsorption and oxidation (R 2 = 0.649), indicating that the adsorption process facilitates synergistic catalytic oxidation, and that as the adsorption rate increases, the degradation rate also increases accordingly. This indicates that compared to other modified carbon materials, BPC-0.25 exhibits excellent adsorption and oxidation synergy. Adsorption and oxidation can occur simultaneously, significantly reducing the time required to degrade the antibiotic and increasing the degradation rate.

[0054] Example 4: The effect of adsorption-oxidation bifunctional boron-doped porous biochar (BPC-0.25) on the degradation of antibiotics under different pH conditions was investigated. Specifically, the adsorption-oxidation bifunctional boron-doped porous biochar was used to activate persulfate to degrade sulfamethoxazole in water, including the following steps: Sulfamethoxazole solutions with pH values ​​of 3, 5, 7, 9, and 11 were prepared respectively (the initial concentration of the solutions was 10 mg / L and the volume was 100 mL), 10 mg of the adsorption-oxidation bifunctional boron-doped porous biochar (BPC-0.25) prepared in Example 1 was added, followed by the addition of 23.8 mg of sodium peroxydisulfate (PDS), and the catalytic degradation reaction was carried out for 30 minutes under stirring at a speed of 450 r / min to complete the degradation of sulfamethoxazole in the water.

[0055] During the catalytic degradation process, samples were taken at 0 min, 5 min, 10 min, 20 min, and 30 min, and the concentration of sulfamethoxazole in each beaker was measured. Finally, the catalytic performance of the adsorption-oxidation bifunctional boron-doped porous biochar (BPC-0.25) under different pH conditions was obtained.

[0056] Figure 9 The following is a graph showing the degradation effect of sulfamethoxazole by activating persulfate at different pH values ​​using the adsorption-oxidation dual-functional boron-doped porous biochar (BPC-0.25) in Example 4 of the present invention. Figure 9 The results showed that under acidic, neutral, and weakly alkaline conditions, the BPC-0.25 / PDS system achieved SMX removal efficiencies exceeding 96% within 30 minutes, demonstrating its excellent applicability within a pH range of 3 to 9. However, at a strongly alkaline pH of 11, electrostatic repulsion between the negatively charged surface of BPC-0.25 and the anionic forms of SMX and PDS was enhanced, hindering adsorption and PDS activation. This significantly inhibited SMX degradation, resulting in a SMX removal efficiency of only 61.7% within 30 minutes. Overall, the BPC-0.25 / PDS system exhibited excellent SMX degradation performance over a wide pH range (3 to 9), demonstrating broad application prospects.

[0057] Example 5: The effect of adsorption-oxidation bifunctional boron-doped porous biochar on the degradation of antibiotics under complex water conditions was investigated. Specifically, the adsorption-oxidation bifunctional boron-doped porous biochar was used to activate persulfate to degrade sulfamethoxazole in water, including the following steps: Prepared separately containing 10mmol / L SO4 2- 、10mmol / L H2PO4 - 、10mmol / L HCO3 - 、10mmol / L Cl - 、10mmol / L NO3 -, a sulfamethoxazole solution containing a 10 mg / L humic acid (HA) interfering substance, and a sulfamethoxazole solution without an interfering substance, wherein the concentration of the above sulfamethoxazole solutions are all 10 mg / L, the volume is all 100 mL, and the pH is all 4.75; take seven 150 mL beakers, add 10 mg of the adsorption-oxidation dual-functional boron-doped porous biochar (BPC-0.25) prepared in Example 1 and the above sulfamethoxazole solution, then add 23.8 mg of sodium persulfate (PDS) to each beaker, and carry out a catalytic degradation reaction for 30 minutes at a stirring speed of 450 r / min to complete the degradation of sulfamethoxazole in the water, and then take samples for determination.

[0058] Figure 10 This is a diagram showing the degradation effect of sulfamethoxazole by activating persulfate in the presence of different interferents using the adsorption-oxidation dual-functional boron-doped porous biochar (BPC-0.25) in Example 5 of the present invention. Figure 10 In the equation, control means no interference. Figure 10 It can be seen that among various anions, SO4 2- The effect on the degradation of sulfamethoxazole is minimal, at 10mmol / L SO4 2- BPC-0.25 / PDS can still completely degrade SMX at the same concentration; - 、NO3 - 、HCO3 - and H2PO4 - After addition of 10 mg / L HA, the SMX removal efficiency of BPC-0.25 / PDS decreased by 3.1%, 4.0%, 7.1%, and 8.1%, respectively, indicating that the SMX removal efficiency was inhibited to varying degrees. When coexisting with 10 mg / L HA, the SMX removal efficiency of BPC-0.25 / PDS decreased to 91.2%. HA also exhibited a slight inhibitory effect on the BPC-0.25 / PDS system. Despite this, the above experimental results indicate that the SMX removal efficiency of the BPC-0.25 / PDS system remained above 90% in the presence of different inorganic ions or HA, demonstrating the system's excellent oxidation performance and anti-interference properties. This indicates that the adsorption-oxidation bifunctional boron-doped porous biochar material (BPC-0.25) prepared in this invention still exhibits stable degradation performance in the presence of various common interfering ions and can be widely used for the removal of antibiotics from various water bodies.

[0059] In summary, the adsorption-oxidation dual-functional boron-doped porous biochar material prepared by the present invention has the advantages of large specific surface area, developed multi-level pore structure, rich oxygen-containing functional groups, good surface affinity and highly reactive boron-doped species BC3, thereby exhibiting excellent adsorption and catalytic properties; when it is applied to persulfate advanced oxidation technology, it can achieve efficient removal of sulfonamide antibiotics mediated by non-free radical pathways, and has the advantages of strong adsorption capacity, high catalytic activity, good recyclability, etc., showing good practical application potential.

[0060] The above description is only a preferred embodiment of the present invention and does not constitute any formal limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can, without departing from the spirit and technical solution of the present invention, use the methods and technical contents disclosed above to make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for preparing an adsorption-oxidation dual-functional boron-doped porous biochar material, characterized in that: The following steps are involved: S1. Mixing alfalfa, sodium bicarbonate, boric acid, and water, and heating until the water is completely evaporated to obtain a mixture; the mass ratio of the alfalfa, sodium bicarbonate, and boric acid is 1:1:0.2-0.75; S2. Pyrolyzing the mixture obtained in step S1 at a temperature greater than 650° C. to obtain an adsorption-oxidation dual-functional boron-doped porous biochar material.

2. The method for preparing the adsorption-oxidation dual-functional boron-doped porous biochar material according to claim 1, characterized in that: In step S1, the mass ratio of alfalfa, sodium bicarbonate and boric acid is 1:1:0.2-0.

3.

3. The method for preparing the adsorption-oxidation dual-functional boron-doped porous biochar material according to claim 2, characterized in that: In step S2, the pyrolysis temperature is 700°C to 900°C.

4. The method for preparing the adsorption-oxidation dual-functional boron-doped porous biochar material according to any one of claims 1 to 3, characterized in that: In step S1, the heating temperature is 80° C. to 90° C., and the heating is performed under stirring conditions. The alfalfa is further processed as follows before use: washing, drying, and crushing the alfalfa.

5. The method for preparing the adsorption-oxidation dual-functional boron-doped porous biochar material according to any one of claims 1 to 3, characterized in that: In step S2, the pyrolysis is carried out under a nitrogen atmosphere, the heating rate during the pyrolysis process is 5°C / min to 10°C / min, and the pyrolysis time is 2h to 4h; after the pyrolysis, the following treatment is also included: washing and drying the pyrolysis product, and the drying temperature is 50°C to 70°C.

6. An adsorption-oxidation dual-functional boron-doped porous biochar material prepared by the preparation method according to any one of claims 1 to 5.

7. The adsorption-oxidation dual-functional boron-doped porous biochar material according to claim 6, characterized in that: The adsorption-oxidation dual-functional boron-doped porous biochar material has microporous and mesoporous structures.

8. Use of the adsorption-oxidation bifunctional boron-doped porous biochar material according to any one of claims 6 to 7 in treating antibiotic wastewater.

9. The use according to claim 8, characterized in that The method comprises the following steps: mixing an adsorption-oxidation dual-functional boron-doped porous biochar material and antibiotic wastewater, adding persulfate, and performing a catalytic degradation reaction to achieve degradation of the antibiotics in the water body.

10. The use according to claim 9, characterized in that The mass ratio of the adsorption-oxidation dual-functional boron-doped porous biochar material to the antibiotic in the antibiotic wastewater is 0.5-10:1, the amount of persulfate added is 0.25 mmol-1 mmol per liter of antibiotic wastewater, the initial concentration of the antibiotic in the antibiotic wastewater is 10 mg / L-50 mg / L, the initial pH value of the antibiotic wastewater is 3-9, the antibiotic in the antibiotic wastewater is a sulfonamide antibiotic, the sulfonamide antibiotic is sulfamethoxazole, the persulfate is sodium peroxydisulfate, the time of the catalytic degradation reaction is ≥20 min, the catalytic degradation reaction is carried out under stirring conditions, and the stirring speed is 300 r / min-500 r / min.

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