Anode system for in-situ generation of high-valence iron synergistic nitrogen modified biochar, preparation method of anode system and application of anode system in degradation of antibiotics in water

Abstract

The invention provides an anode system for in-situ generation of high-valence iron synergistic nitrogen modified charcoal, a preparation method of the anode system and application of the anode system in degradation of antibiotics in a water body, and belongs to the technical field of wastewater treatment. The anode system (E / NBC / Fe (III) system) comprises an anode, a cathode, an electrolyte, a Fe (III) compound and nitrogen modified biochar, an electrolyte is Na2SO4, a reaction solution of an anode system contains antibiotics, a Fe (III) compound and nitrogen-modified biochar, the in-situ generated high-valence iron and nitrogen-modified biochar synergistic anode system can degrade the antibiotics in the water body, and the E / NBC / Fe (III) system can degrade the antibiotics in the water body through a coupling mechanism of electrochemical high-valence iron generation, biochar catalysis and multi-free-radical synergism. The method realizes green and efficient degradation of antibiotics, and has the characteristics of low cost, high adaptability and environmental safety.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, and particularly relates to an anode system for in-situ generation of high-valent iron-synergistic nitrogen-modified biochar, its preparation method, and its application in the degradation of antibiotics in water. Background Technology

[0002] Antibiotics have been widely used since the 20th century and have become important drugs for preventing and treating infectious diseases in humans and animals. However, their high chemical stability and poor biodegradability lead to persistent antibiotic residues in the environment, which accumulate through the food chain, inducing the spread of drug-resistant bacteria and genes, seriously threatening the ecological environment and public health. Sulfonamides, represented by sulfamethoxazole, are widely used in medicine and aquaculture due to their low cost and broad efficacy; however, they are frequently detected in water bodies, and even low concentrations can induce drug resistance, and they can even interfere with the human immune and nervous systems through intestinal absorption. Therefore, research on efficient and green removal technologies for sulfamethoxazole is of significant practical importance.

[0003] Sulfamethoxazole is an antibacterial antibiotic whose mechanism of action is to inhibit dihydrofolate synthase, an enzyme required for the synthesis of folic acid precursors during bacterial growth. According to data from the U.S. Geological Survey, sulfamethoxazole is one of the most frequently detected wastewater pollutants, ranking among the top 30. Its strong antibacterial properties can significantly alter the function of environmental microorganisms; even low concentrations can induce antibiotic-resistant bacteria and the generation of resistance genes. Simultaneously, it can be directly absorbed by human intestinal tissues and the circulatory system, affecting not only the immune system, central and peripheral nervous systems locally or distally, but also indirectly regulating nervous system function through its action on the gut microbiota. Therefore, developing efficient and green methods for the removal of sulfamethoxazole is particularly urgent.

[0004] Currently, antibiotic removal technologies mainly include physical methods, biological methods, and advanced oxidation methods. However, all of these technologies have significant limitations and cannot meet the requirements for efficient removal of sulfonamide antibiotics.

[0005] Traditional physical treatment technologies achieve phase transfer of antibiotics through physical processes such as van der Waals forces, hydrophobic interactions, and gravity. Common methods include adsorption, filtration, and flotation, with adsorption using porous carbon materials with high specific surface area, such as biochar, being the most widely used. However, physical methods can only achieve phase transfer of pollutants and cannot completely degrade antibiotics. They cannot achieve mineralization and detoxification by altering the chemical structure and are prone to secondary pollution due to difficulties in solid-liquid separation of the adsorbent, making it difficult to achieve deep purification goals.

[0006] Biological methods rely on the metabolic activities of microorganisms such as bacteria and fungi to degrade antibiotics into non-toxic substances using them as carbon sources. Common technologies include activated sludge processes, biofilm processes, and biofilters. Although the degradation products have low toxicity, their application is significantly limited: they are only applicable to biodegradable pollutants, have poor adaptability to high-concentration antibiotic wastewater, requiring pre-dilution; the removal cycle is long and inefficient, and they are significantly constrained by environmental factors such as temperature, pH, and dissolved oxygen, making it difficult to control microbial growth conditions and ensuring cost-effectiveness.

[0007] In contrast, advanced oxidation processes have attracted widespread attention because they can completely mineralize or convert pollutants into less toxic products by generating free radicals. However, while existing advanced oxidation technologies (such as Fe(VI) / PMS-based systems) have high degradation efficiency, they rely on external oxidants (such as persulfate), which significantly increases treatment costs. At the same time, excessive addition of oxidants may cause byproduct pollution, and they fail to fully utilize the inherent components in the wastewater (such as sulfate) as oxidant precursors, resulting in resource waste and insufficient economic viability.

[0008] In addition to the limitations of single technologies, existing treatment technologies also face overall bottlenecks: actual wastewater often contains multiple pollutants such as antibiotics, sulfates and transition metals, but existing technologies can usually only remove single pollutants (such as antibiotics). There is a lack of comprehensive treatment systems that can synergistically achieve efficient degradation of antibiotics, conversion of sulfates and recovery of transition metals, making it difficult to achieve the dual goals of wastewater purification and resource utilization, which seriously limits treatment efficiency and economic feasibility.

[0009] Despite existing attempts at improvement, none have systematically solved the aforementioned problems. Therefore, there is an urgent need to develop a novel, low-cost, green, and efficient oxidation system that utilizes electrochemical activation of low-valent iron combined with biochar activation to achieve efficient degradation and mineralization of sulfamethoxazole, while reducing reliance on chemical reagents and providing a sustainable solution for antibiotic pollution control. To this end, this invention proposes an anolyte system for in-situ generation of high-valent iron-synergistic nitrogen-modified biochar, its preparation method, and its application in the degradation of antibiotics in water. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention proposes an anolyte system for in-situ generation of high-valent iron-synergistic nitrogen-modified biochar, its preparation method, and its application in the degradation of antibiotics in water.

[0011] To achieve the above objectives, the present invention provides the following technical solution:

[0012] One of the technical solutions of the present invention:

[0013] An in-situ generation of high-valent iron synergistic nitrogen-modified biochar (E / NBC / Fe(III) system) includes an anode, a cathode, an electrolyte, a trivalent iron compound, and nitrogen-modified biochar; the anode is a titanium sheet, the cathode is a platinum wire, the electrolyte is Na2SO4, and the reaction solution of the anode system contains antibiotics, trivalent iron compounds, and nitrogen-modified biochar.

[0014] Furthermore, the trivalent iron compound is FeCl3·6H2O.

[0015] Furthermore, in the reaction solution of the anode system, the concentration of FeCl3·6H2O is 0.1-2 mmol / L, and the concentration of nitrogen-modified biochar is 0.2-0.8 g / L.

[0016] Furthermore, the amount of electrolyte added to the reaction solution of the anode system is 1 mmol / L.

[0017] Furthermore, the nitrogen-modified biochar is prepared by impregnating corn stalks with urea and then heat-treating them at 600-900℃ for 1-2 hours. Specifically, it includes the following steps:

[0018] (1) Crush the corn stalks with a grinder, pass them through a 60-mesh sieve, and then dry them in an oven at 70-100℃ for use.

[0019] (2) Dissolve 0.05-0.2 mol of urea completely in 100 mL of pure water, then soak 10 g of corn stalk powder in the urea solution, stir with a magnetic stirrer for 8-12 hours, then evaporate and dry at 100 °C, and finally heat-treat the impregnated sample in a tube furnace at 600-900 °C for 1-2 hours at a heating rate of 5-20 °C / min.

[0020] The second technical solution of the present invention:

[0021] A method for preparing the above-mentioned in-situ generated high-valent iron synergistic nitrogen-modified biochar anode system includes the following steps:

[0022] Na2SO4 was added as an electrolyte to a solution containing antibiotics, FeCl3·6H2O and nitrogen-modified biochar. A titanium anode and a platinum wire cathode were inserted, the initial pH of the system was adjusted, and after energizing, the in-situ generated high-valent iron synergistic nitrogen-modified biochar anode system was obtained.

[0023] The third technical solution of the present invention:

[0024] Application of an anodic system for in-situ generation of high-valent iron-co-nitrogen-modified biochar as described above in the degradation of antibiotics in water.

[0025] Furthermore, the concentration of antibiotics in the water body is 5-20 mg / L during application.

[0026] Furthermore, the antibiotic is a sulfonamide antibiotic, such as sulfamethoxazole, sulfamethoxypyridazine, sulfadiazine, sulfadoxine, sulfathiazole, or sulfonamide.

[0027] Furthermore, the method for degrading antibiotics in water using the above-mentioned in-situ generated high-valent iron-co-nitrogen-modified biochar anolyte system includes the following steps:

[0028] FeCl3·6H2O and nitrogen-modified biochar were added to water containing antibiotics, along with Na2SO4 as the electrolyte. A titanium anode and a platinum wire cathode were inserted, and the initial pH of the system was adjusted to 1-9. After energizing, the antibiotics in the water were degraded.

[0029] Furthermore, the voltage applied is 5-15V, and the power-on process takes 30-180 minutes.

[0030] Furthermore, the initial pH of the system was adjusted using NaOH and H2SO4.

[0031] The anolyte system for in-situ generation of high-valent iron-co-nitrogen modified biochar in this invention achieves efficient degradation of antibiotics in water through the synergistic effect of electrochemical action and material catalysis. The specific mechanism is as follows:

[0032] (1) In-situ generation of high-valence iron: In this invention, a titanium sheet is used as the anode. Under energized conditions (5-15V), an electrochemical oxidation reaction occurs at the anode, oxidizing Fe(III) (provided by FeCl3·6H2O) in situ to generate high-valence iron species (Fe(IV) / Fe(V)). This process does not require an external oxidant and directly utilizes electrical energy to drive the valence state of Fe(III), providing a highly oxidizing species for antibiotic degradation.

[0033] (2) Catalytic enhancement of nitrogen-modified biochar: Nitrogen-modified biochar, which is prepared by urea impregnation and heat treatment at 600-900℃, has a porous structure and active sites (such as pyridine nitrogen and pyrrole nitrogen) introduced by nitrogen doping, which can accelerate electron transfer efficiency. On the one hand, it promotes the valence state cycle of Fe(III) / Fe(IV) / Fe(V) and increases the generation rate of high-valence iron. On the other hand, it simultaneously generates hydroxyl radicals (·OH), which enhances the oxidation capacity through the synergistic effect of multiple radicals.

[0034] (3) Co-oxidation and free radical enhancement: In the system, high-valent iron species (Fe(IV) / Fe(V)) and hydroxyl radicals (·OH) form a co-oxidation system. Among them, Fe(IV) directly participates in antibiotic degradation as the main oxide species, while ·OH accelerates degradation by attacking the active sites in antibiotic molecules (such as the SN bond of sulfonamides).

[0035] (4) Degradation pathway of antibiotics: Under the synergistic effect of the above-mentioned active species, antibiotics (especially sulfonamides) undergo reactions such as SN bond cleavage, amination and hydroxylation: the strong oxidizing property of high-valence iron directly breaks the key chemical bonds in antibiotic molecules, while free radicals gradually transform macromolecules into low-toxicity small molecules through addition and substitution reactions, ultimately achieving efficient degradation (for example, the degradation rate of sulfamethoxazole reaches 97.04% within 60 min).

[0036] (5) System adaptability regulation: By adjusting the initial pH (1-9), the existing form of antibiotics (such as the ionic / molecular state of sulfonamides at different pH) and the stability of active species can be optimized; by controlling the energizing time (30-180 min) and the concentration of FeCl3·6H2O (0.1-2 mmol / L) and the concentration of nitrogen-modified biochar (0.2-0.8 g / L), it can be adapted to the degradation requirements of different concentrations of antibiotics (5-20 mg / L) to ensure that it remains highly efficient in actual water bodies (such as Yangtze River water and poultry wastewater).

[0037] Compared with the prior art, the present invention has the following advantages and technical effects:

[0038] (1) The E / NBC / Fe(III) system of the present invention achieves green and efficient degradation of antibiotics through the coupling mechanism of electrochemical high-valence iron generation, biochar catalysis and multi-radical synergy. It has the characteristics of low cost (no need for external oxidant), high adaptability (wide pH range, adaptable to complex water bodies) and environmental safety (low toxicity of degradation products).

[0039] (2) This invention eliminates the need for additional oxidants, solving the key problems of high oxidant consumption and secondary pollution in advanced oxidation technologies. The E / NBC / Fe(III) system of this invention is established for the first time and used for the degradation of sulfonamide antibiotics. From an economic feasibility perspective, the E / NBC / Fe(III) system of this invention has low energy consumption. From a degradation efficiency perspective, E / FeO... x The degradation efficiency of / NHPC750 / H2O2 is 95%, but the required time is 90 minutes. Furthermore, this invention not only maintains high degradation efficiency but also reduces the time to 60 minutes. Therefore, this invention maintains both relatively favorable energy consumption and operating costs while preserving the high degradation efficiency of sulfonamide antibiotics. Attached Figure Description

[0040] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0041] Figure 1The degradation rates of sulfamethoxazole in the mono-E system, binary E / Fe(III) system, and ternary E / NBC / Fe(III) system of Comparative Example 1, Comparative Example 2, and Example 1 are shown.

[0042] Figure 2 The degradation rate of sulfamethoxazole in different actual water bodies in Example 2;

[0043] Figure 3 The degradation rate of different antibiotics by the E / NBC / Fe(III) system in Example 3;

[0044] Figure 4 The degradation rate of sulfamethoxazole by different FeCl3·6H2O concentrations in the E / NBC / Fe(III) system in Example 4 is shown.

[0045] Figure 5 The degradation rate of sulfamethoxazole under different energizing voltages in the E / NBC / Fe(III) system in Example 5;

[0046] Figure 6 The degradation rate of sulfamethoxazole at different initial pH values ​​in the E / NBC / Fe(III) system in Example 6;

[0047] Figure 7 The effect of anions and humic acid on the degradation rate of sulfamethoxazole in the E / NBC / Fe(III) system in Example 7 is shown, where (a)-(f) represent Cl... - NO3 - CO3 2- HCO 3- H2PO4 - and humic acid;

[0048] Figure 8 The effect of cations on the degradation rate of sulfamethoxazole in the E / NBC / Fe(III) system in Example 8 is shown, where (a) is Na + (b) is K + ;

[0049] Figure 9 The results of acute toxicity (LC50) and chronic toxicity (ChV50) tests of the sulfamethoxazole intermediate degradation product of the system in Example 1 on fish, fleas and green algae;

[0050] Figure 10 This is to demonstrate the performance of the system in Example 1 during continuous operation. Detailed Implementation

[0051] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0052] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0053] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0054] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0055] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0056] This invention proposes an anodic system (E / NBC / Fe(III) system) for in-situ generation of high-valent iron synergistic nitrogen-modified biochar, comprising an anode, a cathode, an electrolyte, FeCl3·6H2O, and nitrogen-modified biochar; the anode is a titanium sheet, the cathode is a platinum wire, the electrolyte is Na2SO4, and the reaction solution of the anode system contains antibiotics, FeCl3·6H2O, and nitrogen-modified biochar.

[0057] In a preferred embodiment of the present invention, the concentration of FeCl3·6H2O in the reaction solution of the anode system is 0.1-2 mmol / L, and the concentration of nitrogen-modified biochar is 0.2-0.8 g / L.

[0058] In a preferred embodiment of the present invention, the amount of electrolyte added to the reaction solution of the anolyte system is 1 mmol / L.

[0059] In a preferred embodiment of the present invention, nitrogen-modified biochar is prepared by impregnating corn stalks with urea and then heat-treating them at 600-900°C for 1-2 hours; specifically, it includes the following steps:

[0060] (1) Crush the corn stalks with a grinder, pass them through a 60-mesh sieve, and then dry them in an oven at 70°C for use.

[0061] (2) Dissolve 0.1 mol of urea completely in 100 mL of pure water, then soak 10 g of corn stalk powder in the urea solution, stir with a magnetic stirrer for 12 hours, then evaporate and dry at 100 °C, and finally heat-treat the impregnated sample at 700 °C for 2 hours in a tube furnace at a heating rate of 5 °C / min.

[0062] This invention also proposes a method for preparing the above-mentioned in-situ generated high-valent iron synergistic nitrogen-modified biochar anode system, comprising the following steps:

[0063] Na2SO4 was added as an electrolyte to a solution containing antibiotics, FeCl3·6H2O and nitrogen-modified biochar. A titanium anode and a platinum wire cathode were inserted, the initial pH of the system was adjusted, and an anode system in which high-valent iron synergistically generates nitrogen-modified biochar was obtained after energizing.

[0064] This invention also proposes the application of an anolyte system for in-situ generation of high-valent iron-co-nitrogen-modified biochar, as described above, in the degradation of antibiotics in water.

[0065] In a preferred embodiment of the present invention, the concentration of antibiotics in the water is 5-20 mg / L during application.

[0066] In a preferred embodiment of the present invention, the antibiotic is a sulfonamide antibiotic, such as sulfamethoxazole, sulfamethoxypyridazine, sulfadiazine, sulfadoxine, sulfathiazole, or sulfonamide.

[0067] In a preferred embodiment of the present invention, the method for degrading antibiotics in water using the above-described in-situ generated high-valent iron-co-nitrogen modified biochar anolyte system includes the following steps:

[0068] FeCl3·6H2O and nitrogen-modified biochar were added to water containing antibiotics, along with Na2SO4 as the electrolyte. A titanium anode and a platinum wire cathode were inserted, and the initial pH of the system was adjusted to 1-9. After energizing, the antibiotics in the water were degraded.

[0069] In a preferred embodiment of the present invention, the voltage applied is 5-15V, and the power-on processing time is 30-180min.

[0070] In a preferred embodiment of the present invention, NaOH and H2SO4 are used to adjust the initial pH of the system.

[0071] In a preferred embodiment of the present invention, the cathode and anode materials used include, but are not limited to, titanium sheets and platinum wires. The FeCl3·6H2O used is used to provide ferric iron, and may also be other ferric iron raw materials.

[0072] The energy per order (EEO) of the E / NBC / Fe(III) system of this invention is 2.1 units, and similar systems such as E / FeO... x The EEO of / NHPC750 / H2O2 is 15.6 yuan. A comparison shows that the energy consumption of the E / NBC / Fe(III) system of this invention is relatively low. From an economic feasibility perspective, the cost of degrading 5 ppm is approximately 0.8 yuan.

[0073] The technical solution of the present invention will be further illustrated by the following embodiments.

[0074] Example 1

[0075] A method for degrading antibiotics in water using an anolyte system (E / NBC / Fe(III) system) that utilizes in-situ generated high-valent iron synergistically modified nitrogen biochar, comprising the following steps:

[0076] The process was conducted in a 100 mL glass beaker at a stable temperature of 25 ± 2 °C. FeCl3·6H2O and nitrogen-modified biochar were added to water containing sulfamethoxazole (5 mg / L) to achieve a FeCl3·6H2O concentration of 1 mmol / L and a nitrogen-modified biochar concentration of 0.4 g / L. Na2SO4 was then added as an electrolyte at a concentration of 1 mmol / L. The mixture was stirred on a magnetic stirrer at 800 rpm. A titanium anode and a platinum wire cathode were inserted into the water. The initial pH of the system was adjusted to 1 using 0.1 M NaOH and H2SO4. The degradation of sulfamethoxazole in the water was carried out under a voltage of 15 V.

[0077] Comparative Example 1

[0078] A method for degrading antibiotics in water using a mono-E system includes the following steps:

[0079] The process was carried out in a 100 mL glass beaker at a stable temperature of 25 ± 2 °C. Na₂SO₄ was added as an electrolyte to water containing 5 mg / L sulfamethoxazole at a concentration of 1 mmol / L. The mixture was stirred on a magnetic stirrer at 800 rpm. A titanium anode and a platinum cathode were inserted into the water. The initial pH of the system was adjusted to 1 using 0.1 M NaOH and H₂SO₄. The degradation of sulfamethoxazole in the water was carried out by applying an electric current at 15 V.

[0080] Comparative Example 2

[0081] A method for degrading antibiotics in water using a binary E / Fe(III) system includes the following steps:

[0082] The process was carried out in a 100 mL glass beaker at a stable temperature of 25 ± 2 °C. FeCl3·6H2O was added to water containing sulfamethoxazole (SMX, concentration 5 mg / L) to bring the concentration of FeCl3·6H2O in the water to 1 mmol / L. Then, Na2SO4 was added as an electrolyte at a concentration of 1 mmol / L. The mixture was stirred on a magnetic stirrer at 800 rpm. A titanium anode and a platinum wire cathode were inserted into the water. The initial pH of the system was adjusted to 1 using 0.1 M NaOH and H2SO4. The degradation of sulfamethoxazole in the water was carried out by applying an electric current at 15 V.

[0083] The residual concentration of sulfamethoxazole in Example 1 and Comparative Examples 1-2 was determined by high performance liquid chromatography (HPLC), and the removal rate of sulfamethoxazole at different time points was calculated. The results are shown in [Figure number missing]. Figure 1 .Depend on Figure 1 It can be seen that the degradation efficiencies of the mono-E system, binary E / Fe(III) system, and ternary E / NBC / Fe(III) system of Comparative Example 1, Comparative Example 2, and Example 1 for sulfamethoxazole within 60 min were 2.41%, 74.57%, and 97.09%, respectively. Compared with the mono-E system, the binary E / Fe(III) system showed a significant improvement due to the generation of ferric species (Fe(IV) and Fe(V)). The ternary E / NBC / Fe(III) system of Example 1 of this invention exhibited a better removal rate and removal efficiency of sulfamethoxazole than the binary E / Fe(III) system, achieving a removal efficiency of 97.09% after 60 min of reaction. This is because the nitrogen-modified biochar accelerated the generation of Fe(IV) and Fe(V). This result indicates that the ternary E / NBC / Fe(III) system can achieve efficient degradation of sulfamethoxazole.

[0084] Example 2

[0085] Using the same conditions as in Example 1, the water bodies in Example 1 were replaced with water from Tangxun Lake, Yangtze River, poultry wastewater, and drinking water (the SMX of natural water bodies meets the sanitary standards, so the water body experiment in this example uses natural water bodies as the SMX environment, that is, the water in the experiment is replaced with natural water bodies, so the initial SMX concentration is 5 ppm). The removal effect of the E / NBC / Fe(III) system on sulfamethoxazole in different actual water bodies was determined. The mixture was stirred on a magnetic stirrer at 800 rpm, and samples were taken after 60 min of reaction. The residual concentration of sulfamethoxazole was determined by high performance liquid chromatography to explore the removal effect of the E / NBC / Fe(III) system on sulfamethoxazole in different actual water bodies.

[0086] The degradation rates of sulfamethoxazole in different actual water bodies are shown in the figure. Figure 2 ,Depend on Figure 2 It was found that the degradation rates of sulfamethoxazole by the E / NBC / Fe(III) system in Tangxun Lake water, Yangtze River water, poultry wastewater, and tap water were 100.00%, 68.49%, 77.27%, and 95.76%, respectively. The mechanism of sulfamethoxazole reduction involves different types of ions and organic matter consuming electrons or free radicals and generating other oxide species. The degradation effect was slightly lower in poultry wastewater, possibly because it contains other types of antibiotics that compete with sulfamethoxazole for free radical consumption. In conclusion, the method of this invention can efficiently degrade sulfamethoxazole in actual water bodies and has great promise for practical applications.

[0087] Example 3

[0088] Same as Example 1, except that sulfamethoxazole was replaced with sulfamethoxypyridazine, sulfadiazine, sulfadoxine, sulfathiazole, sulfonamide, and sulfamethoxazole, respectively. The mixture was stirred on a magnetic stirrer at 800 rpm, and samples were taken at 0-60 min of reaction time. The residual concentration of antibiotics was determined by high performance liquid chromatography to explore the broad-spectrum degradation performance of the E / NBC / Fe(III) system.

[0089] The degradation rates of different antibiotics in the E / NBC / Fe(III) system are shown in the figure. Figure 3 ,Depend on Figure 3 It can be seen that the removal rates of sulfamethoxypyridazine, sulfadiazine, sulfadoxine, sulfathiazole, sulfonamide, and sulfamethoxazole by the E / NBC / Fe(III) system are 100%, 100%, 100%, 75.43%, 99.91%, and 97.09%, respectively. This indicates that the method of the present invention has excellent degradation effect on sulfonamide antibiotics.

[0090] Example 4

[0091] Same as Example 1, except that the concentrations of FeCl3·6H2O in the water were 0.1, 0.2, 0.5, 1, and 2 mmol / L (mmol / L is equivalent to mM, the same below). The mixture was stirred on a magnetic stirrer at 800 rpm, and samples were taken from 0 to 60 min into the reaction time. The residual antibiotic concentration was determined by high-performance liquid chromatography (HPLC) to investigate the effect of the FeCl3·6H2O concentration in the E / NBC / Fe(III) system on the degradation rate of sulfamethoxazole.

[0092] The degradation rates of sulfamethoxazole by different FeCl3·6H2O concentrations in the E / NBC / Fe(III) system are shown in the figure. Figure 4 ,Depend on Figure 4It can be seen that the removal rate of sulfamethoxazole by the E / NBC / Fe(III) system increases with the increase of Fe(III) (i.e., FeCl3·6H2O). When the Fe(III) concentration is 1 mmol / L, after a reaction time of 60 min, the removal rate of sulfamethoxazole by the E / NBC / Fe(III) system is approximately 97.09%. This is because the higher the Fe(III) concentration, the more Fe(IV) / Fe(V) is generated by electrolysis, and Fe(IV) / Fe(V) are the main free radicals that degrade sulfamethoxazole. In addition, Fe(II) can also be generated through electron transfer, which can activate SO42-. 2- Degrades sulfamethoxazole.

[0093] Example 5

[0094] Same as Example 1, except that sulfamethoxazole degradation in water was carried out by applying voltages of 5, 10, 15, 20, and 25 V. The mixture was stirred on a magnetic stirrer at 800 rpm, and samples were taken from 0 to 60 min into the reaction time. The residual antibiotic concentration was determined by high-performance liquid chromatography (HPLC) to investigate the effect of the applied voltage on the degradation rate of sulfamethoxazole in the E / NBC / Fe(III) system.

[0095] The degradation rates of sulfamethoxazole under different energizing voltages in the E / NBC / Fe(III) system are shown in the figure. Figure 5 ,Depend on Figure 5 It can be seen that the removal rate of sulfamethoxazole by the ternary E / NBC / Fe(III) system increases with increasing voltage. When the voltage is 15V and the reaction time is 60min, the removal rate of sulfamethoxazole by the ternary system is approximately 97.09%. This is because increasing the voltage provides more electrons to iron(III), thereby generating free radicals and accelerating the reaction in the system.

[0096] Example 6

[0097] Same as Example 1, except that the initial pH of the system was adjusted to 1, 3, 5, 7, and 9 for the degradation of sulfamethoxazole in water. The system was stirred on a magnetic stirrer at 800 rpm, and samples were taken from 0 to 60 min into the reaction time. The residual antibiotic concentration was determined by high-performance liquid chromatography (HPLC) to investigate the effect of the initial pH of the E / NBC / Fe(III) system on the degradation rate of sulfamethoxazole.

[0098] The degradation rates of sulfamethoxazole at different initial pH values ​​in the E / NBC / Fe(III) system are shown in the figure. Figure 6 ,Depend on Figure 6It can be seen that the removal rate of sulfamethoxazole by the ternary E / NBC / Fe(III) system increases with decreasing solution pH. The highest removal rate of sulfamethoxazole (98.55%) is achieved when the solution pH is 1. However, the degradation efficiency gradually decreases with increasing pH. This is because when pH < 1.7, sulfamethoxazole mostly exists in cationic form; when pH < 5.6, it exists in molecular form; and when pH > 5.6, it mostly exists in anionic form.

[0099] Example 7

[0100] In the system of Example 1, anions and humic acid were added to the water, and the effects of anions and humic acid on the degradation rate of sulfamethoxazole were determined. Anions (Cl...) were added to the water. - NO3 - CO3 2- HCO 3- H2PO4 - The concentrations of sulfotrioxazole (SSA) were 0, 1, 5, and 10 mM, and the concentrations of humic acid (HA) were 0, 1, 5, and 10 mg / L. The mixture was stirred on a magnetic stirrer at 800 rpm, and samples were taken from 0 to 60 min. The residual antibiotic concentration was determined by high-performance liquid chromatography (HPLC) to investigate the effects of anions and humic acid in the E / NBC / Fe(III) system on the degradation rate of sulfamethoxazole.

[0101] The effects of anions and humic acid on the degradation rate of sulfamethoxazole in the E / NBC / Fe(III) system are shown in the figure. Figure 7 Where (a)-(f) represent Cl respectively - NO3 - CO3 2- HCO 3- H2PO4 - and humic acid, from Figure 7 As can be seen from (a), Cl - This system promotes the degradation of sulfamethoxazole because Cl - It reacts with ·OH to form ·Cl and ·Cl2, which have high redox potentials. Figure 7 Images (b), (c), (d), and (e) show NO3. - CO3 2- HCO3 - H2PO4 - This system inhibits the degradation of sulfamethoxazole. This is because NO3... - It will compete with sulfamethoxazole for electrons, generating NO3- and NO2- with low oxidizing power. CO3 2- and HCO3 - With SO4·- ·OH and Fe(IV) exhibit high reactivity, generating CO3· with low oxidizing power. - and HCO3· H2PO4 - Regarding SO4· - It has a quenching effect and also reacts rapidly with Fe(III) to form FeH2PO4. 2+ . Figure 7 Figure (f) shows that the removal rate of sulfamethoxazole decreased slightly with increasing humic acid concentration, from 97.08% to 82.83%. This is because humic acid has the ability to compete with the target pollutant for free radicals. However, the system can still maintain a high degradation rate in the presence of high concentrations of humic acid.

[0102] Example 8

[0103] In the system of Example 1, cations were added to the water to set the cations (Na+). + K + The concentrations of antibiotics were 0, 1, 5 and 10 mM, respectively, and the mixture was stirred on a magnetic stirrer at 800 rpm. Samples were taken from 0 to 60 min of reaction time, and the residual concentration of antibiotics was determined by high performance liquid chromatography to investigate the effect of cations in the E / NBC / Fe(III) system on the degradation rate of sulfamethoxazole.

[0104] The effect of cations on the degradation rate of sulfamethoxazole in the E / NBC / Fe(III) system is shown in the figure. Figure 8 , where (a) is Na + (b) is K + .Depend on Figure 8 It can be seen that Na + This system promotes the degradation of sulfamethoxazole. + It has a slight inhibitory effect on the degradation of sulfamethoxazole, but can still maintain a degradation rate of over 90%.

[0105] Example 9

[0106] To evaluate the acute toxicity (LC50) and chronic toxicity (ChV50) of the intermediate products generated from the degradation of sulfamethoxazole in the system of Example 1 to fish, fleas, and green algae, simulations were performed using ECOSAR 2.0. The specific steps are as follows: the molecular structures of the degradation products were plotted using Chemdraw, and the SMILE code was copied to ECOSAR 2.0 software for prediction calculations. The results are shown below. Figure 9 .according to Figure 9 It can be seen that the overall toxicity of all degradation products of sulfamethoxazole is lower than that of sulfamethoxazole, indicating that the system has a good degradation effect on sulfamethoxazole.

[0107] Example 10

[0108] To investigate the continuous operation capability of the system in Example 1, a continuous experiment was conducted. Each test lasted for 60 minutes. After the test, the concentration of sulfamethoxazole was replenished to 5 mg / L, and the experiment was repeated 5 times.

[0109] Figure 10 It can be seen that after 5 cycles, the removal rate of sulfamethoxazole can still reach 70.54%, indicating that the system has good continuous operation capability.

[0110] All the raw materials listed in this invention, as well as the upper and lower limits and ranges of the raw materials and the upper and lower limits and ranges of the process parameters (such as temperature, time, etc.), can realize this invention. Examples are not listed one by one here.

[0111] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An anode system for in-situ generation of high-valent iron-co-nitrogen-modified biochar, characterized in that, It includes anode, cathode, electrolyte, ferric compounds, and nitrogen-modified biochar; The anode is a titanium sheet, the cathode is a platinum wire, and the electrolyte is Na2SO4. The reaction solution of the anode system contains antibiotics, ferric compounds, and nitrogen-modified biochar.

2. The anode system for in-situ generation of high-valent iron-co-nitrogen-modified biochar according to claim 1, characterized in that, In the reaction solution of the anode system, the concentration of ferric compounds is 0.1-2 mmol / L, and the concentration of nitrogen-modified biochar is 0.2-0.8 g / L.

3. The anode system for in-situ generation of high-valent iron-co-nitrogen-modified biochar according to claim 1, characterized in that, The concentration of the electrolyte in the reaction solution of the anolyte system is 1 mmol / L.

4. The anode system for in-situ generation of high-valent iron-synergistic nitrogen-modified biochar according to claim 1, characterized in that, The nitrogen-modified biochar is prepared by impregnating corn stalks with urea and then heat-treating them at 600-900℃ for 1-2 hours.

5. A method for preparing an anode system for in-situ generation of high-valent iron-synergistic nitrogen-modified biochar as described in any one of claims 1-4, characterized in that, Includes the following steps: Na2SO4 was added as an electrolyte to a solution containing ferric compounds and nitrogen-modified biochar. A titanium anode and a platinum wire cathode were inserted, the initial pH of the system was adjusted, and after energizing, the in-situ generated ferric synergistic nitrogen-modified biochar anode system was obtained.

6. The application of an anodic system for in-situ generation of high-valent iron-synergistic nitrogen-modified biochar as described in any one of claims 1-4 in the degradation of antibiotics in water.

7. The application of the in-situ generated high-valent iron synergistic nitrogen-modified biochar anolyte system according to claim 6 in the degradation of antibiotics in water, characterized in that, When applying the antibiotic, the concentration of the antibiotic in the water body should be 5-20 mg / L.

8. The application of the in-situ generated high-valent iron synergistic nitrogen-modified biochar anolyte system according to claim 7 in the degradation of antibiotics in water, characterized in that, The antibiotic in question is a sulfonamide antibiotic.

9. The application of the in-situ generated high-valent iron synergistic nitrogen-modified biochar anolyte system according to claim 6 in the degradation of antibiotics in water, characterized in that, The method for degrading antibiotics in water using the in-situ generated high-valent iron-co-nitrogen modified biochar anolyte system includes the following steps: Ferric compounds and nitrogen-modified biochar were added to water containing antibiotics, along with Na2SO4 as an electrolyte. A titanium anode and a platinum wire cathode were inserted, and the initial pH of the system was adjusted to 1-9. After energizing, the antibiotics in the water were degraded.

10. The application of the in-situ generated high-valent iron synergistic nitrogen-modified biochar anolyte system according to claim 9 in the degradation of antibiotics in water, characterized in that, The voltage applied is 5-15V, and the power-on process takes 30-180 minutes.

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