Method for degrading antibiotic pollutants by using boron-carbon co-regulated nanoscale zero-valent iron as activating agent

Abstract

The invention belongs to the technical field of antibiotic pollutant degradation, and discloses a method for degrading antibiotic pollutants by using boron-carbon co-regulated nanoscale zero-valent iron as an activating agent, which comprises the following steps: step 1, synthesizing carbon-coated nanoscale zero-valent iron, marked as Fe0-C, through a hydrothermal method and a carbothermic method; and step 2, mixing the Fe < 0 >-C obtained in the step 1 with crystal boron, adding the mixture into sewage containing antibiotic pollutants, and then adding persulfate as an oxidizing agent to degrade the antibiotic pollutants. A boron-carbon co-regulation method is adopted to realize the passivation resistance of the nano zero-valent iron in the whole process from preparation, storage to application, and the nano zero-valent iron is applied to the process of activating persulfate to degrade tetracycline.

Description

Technical Field

[0001] This invention relates to the field of antibiotic pollutant degradation technology, and in particular to a method for degrading antibiotic pollutants using boron-carbon co-regulated nano-zero-valent iron as an activator. Background Technology

[0002] The persistent presence of antibiotic pollutants in aquatic environments can lead to the development of drug-resistant bacteria and resistance genes, posing a potential threat to the ecological environment and human health. Persulfate advanced oxidation technology (PAO) has shown significant advantages in antibiotic remediation due to its strong oxidizing properties, wide pH adaptability, and long half-life. However, the application of PAO typically requires external energy or electron transfer to generate highly oxidizing reactive oxygen species (ROS). While traditional activation technologies such as heat, light, and microwave can effectively generate ROS, their high energy consumption limits their application in practical pollution remediation. In contrast, metal-based activation materials, especially nano-zero valent iron (nZVI), have attracted widespread attention due to their environmentally friendly characteristics. nZVI can continuously activate PAO through surface corrosion reactions, offering the advantages of both low cost and high reactivity. However, in practical engineering applications, zero-valent iron is prone to catalytic efficiency degradation due to surface passivation, hydrogen evolution reactions, and nanoparticle aggregation. Surface sulfidation, carbon-based material composites, or loading onto porous supports (such as biochar and montmorillonite) can significantly enhance the dispersibility and stability of nZVI, thereby improving its effective electron utilization. However, existing modification strategies mostly focus on overcoming its aggregation defects and side reactions, and breakthroughs in the inherent passivation mechanism of nZVI are still lacking. Passivation of zero-valent iron is involved throughout the entire process from preparation, storage, transportation to application, and the dense oxide film formed by passivation can also lead to the covering of active sites and the blockage of electron transport channels. This makes it difficult for the service life of nZVI to meet practical engineering requirements, becoming a core bottleneck restricting its large-scale application.

[0003] Overcoming the passivation defect of nZVI aims to improve its effective electron utilization. However, due to the unavoidable passivation of nZVI in existing studies, pretreatment techniques such as acid washing and hydrogen reduction are typically used to remove the surface passivation layer before use to improve its reactivity. However, existing strategies have significant limitations: on the one hand, the passivation layer stripping process is accompanied by the loss of electrons from active iron nuclei; on the other hand, newly exposed nZVI surfaces can form an oxide layer 1 nm thick in air in just 0.2 fs, and the oxide layer thickness can increase to about 3 nm over time, making it difficult to maintain long-term activity through pretreatment. Therefore, from the nZVI preparation stage, controlling the preparation method to achieve passivation resistance is crucial to effectively suppress the subsequent passivation process. Carbon-coated nano-zero-valent iron (Fe) prepared by combining hydrothermal and carbothermal processes... 0@C) can effectively inhibit its air passivation process, and after being stored in air for 120 days, its activity is comparable to that of freshly prepared Fe. 0 @C is almost identical. However, in Fe 0 In practical applications of @C-activated persulfate for pollutant degradation, this system still suffers from a bottleneck problem in reaction kinetics: a "fast at first, slow later" pattern. After the rapid reaction phase (0-15 min), ferrous ions (Fe...)... 2+ The release rate drops sharply and the reaction rate constant decreases by three orders of magnitude. This is because, in addition to the conventional oxidation passivation pathway, the surface deposition of iron-based products during the reaction forms a dense passivation layer, forcing the electron transfer mode to change from direct contact to Fe. 0 Multiphase transport in the core-passivation layer-solution phase significantly increases the electron transport barrier, thereby leading to Fe 0 Electrons cannot be fully released. Therefore, how to suppress Fe through regulation methods is a key issue. 0 The deposition of iron ions during the activation process of @C remains an important scientific problem that needs to be solved in the practical application of nZVI for pollution remediation.

[0004] Previous studies have proposed various strategies to suppress the formation of iron (hydrogen) oxide passivation layers on the surface of iron-based nanoparticles caused by the oxidation and hydrolysis of iron ions. One strategy is to introduce organic ligands (such as ethylenediaminetetraacetic acid) to immobilize iron ions through complexation, thereby inhibiting their deposition and accelerating the formation of Fe. 0 Surface trivalent iron (Fe) 3+ ) to Fe 2+ The first method involves conversion; the second method uses small molecule acids (such as citric acid) to regulate the pH of the reaction system and inhibit the crystallization and precipitation of iron (hydrogen) oxides. However, the use of organic ligands (such as ethylenediaminetetraacetic acid) will compete with the target pollutant for ROS in the reaction system and generate secondary pollution. Furthermore, the continuous addition of small molecule acids increases operating costs and consumes Fe. 0 The available electrons. More fundamentally, existing strategies are mostly designed for the application stage of nZVI, and a systematic anti-passivation scheme has not yet been formed that runs through the entire process of nZVI preparation, storage, and application. This has become a key bottleneck restricting the large-scale application of nZVI technology. However, to date, no control strategy that can achieve anti-passivation throughout the entire process of nZVI has been reported. Summary of the Invention

[0005] The purpose of this invention is to address the technical deficiencies in the prior art by providing a method for degrading antibiotic pollutants using boron-carbon co-regulated nano-zero-valent iron as an activator.

[0006] The technical solution adopted to achieve the purpose of this invention is: A method for degrading antibiotic pollutants using boron-carbon co-regulated nano-zero-valent iron as an activator includes the following steps: Step 1: Carbon-coated nano-zero-valent iron, denoted as Fe, is synthesized via hydrothermal and carbothermal methods. 0 @C; Step 2, take the Fe obtained in Step 1 0 @C is mixed with crystalline boron and added to wastewater containing antibiotic pollutants. Persulfate is then added as an oxidant to degrade the antibiotic pollutants.

[0007] In the above technical solution, in step 1, Fe 0 The preparation method of @C includes the following steps: Glucose and nano-ferric oxide were dissolved in deionized water and subjected to a hydrothermal reaction. After filtration, washing, and freeze-drying, a carbothermal reaction was carried out under a protective gas environment to obtain carbon-coated nano-zero-valent iron.

[0008] In the above technical solution, the molar ratio of carbon in the glucose to iron in nano-ferric oxide is (16~22):1; the hydrothermal reaction temperature is 180℃~200℃, and the reaction time is 8~10 hours; during washing, ethanol and deionized water are used for washing respectively; the freeze-drying temperature is -40℃~-50℃, and the freeze-drying time is 4~6 hours; the carbothermal reaction temperature is 550℃~700℃, and the reaction time is 2~3 hours.

[0009] In the above technical solution, in step 2, Fe 0 The mass ratio of C to crystalline boron is (1~4):1.

[0010] In the above technical solution, in step 2, the persulfate is sodium persulfate, potassium persulfate, or ammonium persulfate.

[0011] In the above technical solution, in step 2, the antibiotic contaminant is a tetracycline, sulfonamide, quinolone, macrolide, β-lactam, or chloramphenicol.

[0012] In the above technical solution, in step 2, the pH value of the wastewater containing antibiotic pollutants is 3 to 11, preferably 7.

[0013] In the above technical solution, in step 2, the amount of persulfate added is 0.5~4 mmol / L, preferably 0.5~1 mmol / L.

[0014] In the above technical solution, in step 2, the amount of crystalline boron fed is 0~200 mg / L, preferably 100~200 mg / L, and Fe... 0 The dosage of @C is 50~400mg / L, preferably 200~400mg / L.

[0015] Another aspect of the present invention includes the application of persulfate as an oxidant and carbon-coated nano-zero-valent iron synergistically crystallized boron as an activator of persulfate in the degradation of antibiotic pollutants.

[0016] Compared with the prior art, the beneficial effects of the present invention are: This invention employs a boron-carbon co-regulation method to achieve passivation resistance throughout the entire process of nano-zero-valent iron, from preparation and storage (achieved through carbon coating of nano-zero-valent iron) to application (achieved through boron crystals), and applies it to the activated persulfate degradation of tetracycline process, specifically including: 1. Compared to simply using Fe 0 @C acts as a persulfate activator, crystalline boron coupled with Fe 0 The @C system can achieve ultra-efficient tetracycline removal and higher tetracycline mineralization rate; 2. Crystalline boron / Fe 0 The @C / persulfate system has a wide pH range for tetracycline degradation; 3. Crystallized boron can accelerate Fe 0 @C / The redox process of iron ions in the persulfate system, thereby inhibiting the redox reaction of iron ions in Fe. 0 Deposition on the C surface; 4. Crystalline boron can continuously expose active sites through surface self-cleaning during the process of accelerating iron ion cycling; 5. Crystalline boron coupled with Fe 0 The @C system achieves passivation resistance throughout the entire process from preparation to application of nano-zero valent iron. Attached Figure Description

[0017] Figure 1 For Fe 0 Scanning electron microscope (SEM) images of C and crystalline boron; Figure 2 For Fe 0 X-ray diffraction (XRD) patterns of C and crystalline boron. Figure 3 Figures showing the tetracycline degradation efficiency and TOC mineralization rate in different reaction systems; Figure 4 To evaluate the effect of different initial pH conditions on crystalline boron / Fe 0 @C / Persulfate system (Boron / Fe) 0 The effect of @C / PDS on tetracycline removal and the pH change of the reaction system over time; Figure 5 For different persulfate dosages, the effect on Boron / Fe 0 The effect of the C / PDS system on tetracycline removal and the persulfate conversion efficiency in systems with different persulfate dosages; Figure 6For different boron crystal dosages and Fe 0 @C dosage versus Boron / Fe 0 The effect of the C / PDS system on the removal of tetracycline; Figure 7 For different quenching agents on Boron / Fe 0 @C / PDS system and Fe 0 Quenching effect and electron paramagnetic resonance spectrum of the C / persulfate system; Figure 8 For Boron / Fe 0 @C / PDS system and Fe 0 Iron ion leaching concentration diagram in the C / PDS system; Figure 9 The images show the X-ray photoelectron spectroscopy (XPS) spectra of crystalline boron before and after the reaction, as well as the leaching concentration. Figure 10 For the original Fe 0 @C and Fe after reaction in different systems 0 XPS graph of @C; Figure 11 Fe before and after the reaction in different systems 0 SEM and elemental diagram of @C. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0019] Example 1 A method for degrading antibiotic pollutants using boron-carbon co-regulated nano-zero-valent iron as an activator includes the following steps: Step 1: Preparation of carbon-coated nano-zero valent iron (Fe) 0 @C), the specific steps are as follows: 7.92 g of hydrated glucose was added to 80 mL of deionized water and stirred until the glucose was fully dissolved. Then, 1.16 g of nano-Fe3O4 was added to the mixture, and the mixture was sonicated and stirred for 1 to 2 minutes to fully disperse the nano-Fe3O4. After sonication, the mixture was quickly transferred to a 120 mL reaction vessel lined with polytetrafluoroethylene and heated in a forced-air drying oven at 180°C–200°C for 8–10 hours. After the reaction vessel cooled to room temperature, the mixture was filtered, and then washed three times with ethanol and deionized water respectively. The black solid particles were then freeze-dried for 4–6 hours to remove moisture. The dried black solid particles were calcined in a vacuum tube furnace at 700°C for 2 hours under a nitrogen atmosphere to obtain Fe. 0 @C.

[0020] In this step, carbon-coated nano-zero-valent iron is prepared by combining hydrothermal and carbothermal reduction methods. This method has a simple preparation process and can achieve the passivation resistance of nano-zero-valent iron, which has good application scenarios in the field of environmental remediation.

[0021] The formation of a high-level oxidation system using persulfate as an oxidant and carbon-coated nano-zero-valent iron synergistically crystallized boron as an activator of persulfate, generates reactive oxygen species that can oxidize various types of antibiotics. In this embodiment, tetracycline is used as an example for illustration.

[0022] Step 2, Fe 0 @C and crystalline boron are directly mixed and added to 50 mL of wastewater containing tetracycline. Sodium persulfate (PDS) is then added as an oxidant to initiate the degradation reaction, thereby achieving an ultra-efficient degradation process of tetracycline. The reaction system is denoted as Boron / Fe 0 @C / PDS. The tetracycline concentration is 20 mg / L, Fe... 0 @C dosage (50, 100, 200, 400 mg / L), crystalline boron dosage (25, 50, 100, 200 mg / L), sodium persulfate dosage (0.5, 1, 2, 4 mM), initial pH (3, 5, 7, 9, 11).

[0023] Figure 1 For Fe 0 Scanning electron microscope (SEM) images of C and crystalline boron, by Figure 1 From (a), we can see that the synthesized Fe 0 @C consists of spherical particles with an average size of approximately 2 μm and a smooth carbon layer on the surface. Figure 1 As shown in (b), crystalline boron consists of irregular particles of about 2 μm.

[0024] Figure 2 For Fe 0 X-ray diffraction (XRD) patterns of C and crystalline boron, by Figure 2 From (a), we can know that Fe 0 Fe appeared at 44.9°, 65.3°, and 82.5°. 0 The peak, diffraction pattern and Fe 0 The standard XRD pattern (JCPDS 06-0696) shows excellent agreement, indicating the successful synthesis of carbon-coated nano-zero-valent iron. Furthermore, the XRD pattern obtained from... Figure 2 As shown in (b), the XRD pattern of crystalline boron indicates that it is β-Boron (JCPDS 80-0323).

[0025] Comparative Example 1 Crystalline boron was added to 50 mL of wastewater containing tetracycline to initiate the degradation reaction. This reaction system is denoted as Boron. The tetracycline concentration was 20 mg / L, and the crystalline boron dosage was 100 mg / L.

[0026] Comparative Example 2 Crystalline boron was added to 50 mL of wastewater containing tetracycline, and sodium persulfate (PDS) was added as an oxidant to carry out the degradation reaction. The reaction system was denoted as Boron / PDS. The tetracycline concentration was 20 mg / L, the crystalline boron dosage was 100 mg / L, and the sodium persulfate dosage was 1 mM.

[0027] Comparative Example 3 Sodium persulfate (PDS) was added to 50 mL of wastewater containing tetracycline to carry out a degradation reaction. The reaction system was designated as PDS only. The tetracycline concentration was 20 mg / L, and the sodium persulfate dosage was 1 mM.

[0028] Comparative Example 4 Fe 0 @C was added to 50 mL of wastewater containing tetracycline for degradation, wherein the tetracycline concentration was 20 mg / L, and Fe... 0 @C dosage is 200 mg / L.

[0029] Comparative Example 5 Fe 0 @C was directly mixed with crystalline boron and added to 50 mL of wastewater containing tetracycline to carry out a degradation reaction. The reaction system is denoted as Boron / Fe. 0 @C, where the tetracycline concentration is 20 mg / L, the boron crystalline dosage is 100 mg / L, and Fe 0 @C dosage is 200 mg / L.

[0030] Comparative Example 6 Nano-zero valent iron (nZVI) was added to 50 mL of wastewater containing tetracycline, and sodium persulfate (PDS) was added as an oxidant to carry out the degradation reaction. The reaction system was denoted as nZVI / PDS. The tetracycline concentration was 20 mg / L, the nano-zero valent iron (nZVI) dosage was 107 mg / L, and the sodium persulfate dosage was 1 mM.

[0031] Comparative Example 7 Fe 0 @C was directly added to 50 mL of wastewater containing tetracycline, followed by the addition of sodium persulfate (PDS) as an oxidant for degradation. The reaction system is denoted as Fe. 0 @C / PDS. The tetracycline concentration is 20 mg / L, Fe... 0 @C dosage is 200 mg / L, sodium persulfate dosage is 1 mM.

[0032] Test Example 1 The tetracycline degradation efficiency and TOC mineralization rate in different reaction systems of Example 1 and Comparative Examples 1 to 7 were tested, and the results are as follows: Figure 3 As shown. By Figure 3 As can be seen in (a), and in Comparative Examples 2 and 5, crystalline boron has no activating effect on persulfate, and its effect on Fe... 0 @C does not have a separate enhancing effect; as can be seen from Comparative Examples 6 and 7, the activation efficiency of conventional nZVI for PDS is very limited, Fe 0 @C is superior to conventional nZVI for PDS, but still suffers from the problem of a fast initial reaction rate followed by a slowdown. In Example 1, Boron / Fe... 0 The @C / PDS system exhibited ultrafast removal efficiency for tetracycline, achieving 100% removal within 1 minute. Furthermore, the residual TOC concentration in different systems was measured, and the results are as follows: Figure 3 As shown in (b), Fe 0 @C will leach out some TOC (Fe) due to the dissolution of the carbon shell. 0 @C / DW, Fe 0 @C dispersed in deionized water), while relative to Fe 0 @C / PDS system: TOC removal rate of 30.67%, Boron / Fe 0 The @C / PDS system achieved a TOC removal rate of 52.03%, demonstrating the effectiveness of crystalline boron in removing Fe. 0 The strengthening effect of the @C / PDS system.

[0033] Test Example 2 The effect of different initial pH conditions on Boron / Fe in Example 1 0 The effect of the C / PDS system on tetracycline removal and the change of pH in the reaction system over time were tested, and the results are as follows: Figure 4 As shown. Figure 4 As can be seen in (a), Boron / Fe 0 The @C / PDS system effectively degraded TC under all pH conditions, with the most significant degradation effect observed at an initial pH of 7. Although strong acid and strong alkaline conditions had some impact on the TC degradation effect in the initial stage of the reaction, the removal rate reached nearly 90% after 15 minutes of reaction. Figure 4 As shown in (b), the pH trends of different reaction systems indicate that, except for the system with an initial pH of 11, the pH of other systems rapidly decreases to around 3 at the beginning of the reaction and then slightly increases as the reaction progresses. This may be because a large number of hydrogen ions are generated during the decomposition of PDS in the early stage of the reaction, while Fe... 0The in-situ Fenton reaction and its reaction with water produced some hydroxide ions, resulting in a slight increase in pH. Under the condition of an initial pH of 11, the pH of the reaction system decreased continuously with the extension of reaction time, dropping to 5.07 after 15 min. This may be due to the large amount of hydrogen ions generated by the alkaline hydrolysis of PDS and the hydrolysis of sulfate free radicals during the reaction.

[0034] Test Example 3 For different persulfate dosages in Example 1, the effect on Boron / Fe 0 The effects of the @C / PDS system on tetracycline removal and the persulfate conversion efficiency in systems with different persulfate dosages were tested, and the results are as follows: Figure 5 As shown. By Figure 5 As can be seen in (a), with the increase of PDS dosage, Boron / Fe 0 The degradation efficiency of TC in the @C / PDS system initially increased and then decreased. When the PDS concentration increased from 0.5 mmol / L to 1 mmol / L, the TC removal rate increased from 61.71% to 100% after 1 min of reaction. Increasing the PDS dosage increased the ROS concentration in the reaction system, thereby improving the tetracycline removal rate. However, with further increases in PDS dosage, the TC removal rate in the reaction system began to decrease. This is due to the quenching of free radicals by excessive PDS and the recombination of free radicals in the co-catalytic system. Figure 5 As shown in Figure (b), the conversion rates of PDS in different PDS addition systems also confirm this conclusion. When the PDS concentration does not exceed 1 mM, its conversion rate in the reaction process is close to 100%, while the conversion rate decreases continuously with the increase of PDS dosage. It should be noted that although the conversion rate decreases with the increase of PDS dosage, the actual conversion amount increases, thus generating excessive free radicals in the reaction system. Therefore, the dosage of PDS should be controlled at an appropriate concentration.

[0035] Test Example 4 Different dosages of crystalline boron and Fe in Example 1 0 @C dosage versus Boron / Fe 0 The effect of removing tetracycline from the @C / PDS system was tested, and the results are as follows: Figure 6 As shown, with the crystal boron ( Figure 6 (a) and Fe 0 @C dose ( Figure 6 As shown in (b), the removal rate of TC in the reaction system increased with the increase of Fe. 0 Increasing the @C dosage can provide more reaction sites and available electrons to the reaction system, while increasing the concentration of boron crystals can enhance the iron ion circulation process in the reaction system, thereby continuously activating PDS to degrade tetracycline.

[0036] Test Example 5 This example compares the effects of different quenchers (MeOH, TBA, BQ, and DABCO) on the Boron / Fe ratio of Example 1. 0 @C / PDS system and Fe of Comparative Example 7 0 The quenching effect of the @C / PDS system was tested, and the results are as follows: Figure 7 As shown. By Figure 7 As can be seen in (a) to (b), the quenching experiment results show that the boron coupling did not change the ROS formation pathway in the reaction system. 0 @C / PDS system and Fe 0 The @C / PDS system contains multiple ROS, with singlet oxygen as the main active species. Furthermore, [the following text appears to be incomplete and requires further context: "by..."] Figure 7 As can be seen in (c) to (f), the electron paramagnetic resonance spectra show Boron / Fe 0 The concentration of ROS in the C / PDS system is higher than that of Fe. 0 The @C / PDS system indicates that the introduction of crystalline boron enhances Fe... 0 @C activates PDS, thus generating more ROS.

[0037] Test Example 6 For Boron / Fe in Example 1 0 @C / PDS system and Fe of Comparative Example 7 0 The iron ion leaching concentration in the @C / PDS system was tested, and the results are as follows: Figure 8 As shown. By Figure 8 As can be seen in (a), in Fe 0 In the @C / PDS system, a large number of ferric ions appear in the initial stage of the reaction, while the concentration of ferrous ions is relatively low. After 8 minutes of reaction, Fe... 0 In the @C / PDS system, the concentration of ferrous ions (Fe2+) increases continuously with increasing reaction time, while the concentration of ferric ions (Fe3+) decreases continuously with increasing reaction time. This is because the concentration of Fe2+ decreases in the later stages of the reaction. 0 The reduction of ferric ions also means that ferric ions begin to form in Fe. 0 @C surface deposition. However, when crystalline boron is introduced as a co-catalyst into the reaction system, although Boron / Fe... 0 The concentration of ferric ions in the @C / PDS system also showed a trend of first increasing and then decreasing. However, during the entire reaction process, the concentration of ferric ions was only higher than that of ferrous ions at 5 min, indicating that the introduction of crystalline boron effectively accelerated the iron ion circulation process in the reaction system, thus ensuring sufficient ferrous ions required for PDS activation. Furthermore, after 5 min of reaction, the Boron / Fe... 0The concentration of ferric ions in the @C / PDS system continued to decrease and almost completely disappeared after 11 min. Correspondingly, the concentration of ferrous ions continued to increase after 5 min of reaction, reaching 1.05 mM after 15 min, indicating that the introduction of crystalline boron effectively suppressed the accumulation of ferric ions in the reaction system. Furthermore, as... Figure 8 As shown in (b), Fe 0 In the @C / PDS system, the release of total iron ions gradually stopped after 11 min of reaction, and the total iron ion concentration in the reaction system was 0.69 mM after 15 min of reaction. However, in the Boron / Fe... 0 In the @C / PDS system, the total iron ion concentration increased with increasing reaction time, reaching 1.05 mM after 15 min of reaction. This indicates that crystalline boron inhibits the activity of ferric ions in Fe by enhancing the iron ion cycling process. 0 The surface deposition enables the nZVI to achieve passivation resistance throughout the entire process.

[0038] Test Example 7 The X-ray photoelectron spectroscopy (XPS) spectra and leaching concentrations of crystalline boron before and after the reaction were measured in Examples 1, 1, 2, and 5. The results are as follows: Figure 9 As shown. By Figure 9 As can be seen in (a), primordial boron (B) exists on the surface of the primordial boron. 0 , 72.54%), interfacial boron suboxides (B(I) and B(II), 25.41%) and boron oxide (B(III), 2.05%). From Figure 9 As shown in (b), after the reaction, the proportion of primary boron on the boron surface decreased from 72.54% to 59.02%, while the proportion of interfacial boron suboxide increased from 25.41% to 38.77%. The decrease in primary boron content and the increase in interfacial boron suboxide content after the reaction indicate that the BB structure on the boron surface and the interfacial boron suboxide accelerate the iron ion cycling process by transferring electrons to ferric iron. Furthermore, from... Figure 9 As shown in (c), Fe appeared in the XPS spectrum of the residual boron after the reaction. 3+ (712.96 and 725.09 eV) and Fe 2+ (710.15 and 723.12 eV), further proving Fe 3+ The reduction process occurs on the boron surface. (By...) Figure 9 As can be seen in (d), compared to other reaction systems, Boron / Fe 0 The concentration of dissolved boron in the @C / PDS system increases significantly, which means that during the reaction, the boron surface undergoes a self-cleaning process after the reduction of ferric iron to ensure that the surface can continuously drive the iron ion cycling process, thereby enhancing the Fenton-like reaction.

[0039] Test Example 8 For the original Fe 0 @C and Boron / Fe of Example 1 0 @C / PDS system and Fe of Comparative Example 7 0 Fe after reaction in the C / PDS system 0 The XPS spectra of @C were tested, and the results are as follows: Figure 10 As shown, by Figure 10 As can be seen in (a), the original Fe 0 Fe present on the C surface 0 ,Depend on Figure 10 As can be seen in (b)-(c), the Fe after the reaction in different systems 0 @C surface Fe 0 All disappeared. For example... Figure 10 As shown in (b), after the reaction, Fe 0 In the @C / PDS system, the content of divalent iron on the surface of the composite material increased from 21.77% to 26.41%, while the content of trivalent iron decreased from 77.31% to 73.59%. This indicates that during the PDS activation process, Fe... 0 The @C surface gradually passivates, causing electrons to transfer only from the core to the outside during subsequent activation. For example... Figure 10 As shown in (c), after introducing crystalline boron as a co-catalyst, Fe 0 The content of divalent iron on the C surface decreased from 21.77% to 17.92%, while the content of trivalent iron increased from 73.59% to 82.07%. This indicates that the crystalline boron inhibited the growth of Fe. 0 The iron ion deposition passivation of @C allows more electrons in the composite material to be used to activate PDS to degrade tetracycline.

[0040] Test Example 9 Original Fe 0 @C and Boron / Fe of Example 1 0 @C / PDS system and Fe of Comparative Example 7 0 Fe before and after the reaction in the C / PDS system 0 SEM and elemental diagram of @C are as follows: Figure 11 As shown, by Figure 11 As can be seen in (a), the original Fe 0 @C surface exhibits a smooth carbon shell, composed of Figure 11 As can be seen in (b), Fe 0 In the @C / PDS system, the carbon layer on the surface of the composite material slightly detached after the reaction. It is worth noting that... Figure 11 As shown in (c), the introduction of crystalline boron leads to the shedding of a large amount of carbon shell from the surface of the composite material, resulting in a spherical, flower-like morphology. Besides the difference in surface morphology, the... Figure 11As shown in (d)-(e), the elemental mapping diagram reveals that the original composite material surface contains very little iron. However, after adding crystalline boron as a co-catalyst, a large amount of iron appears on the composite material surface. This also proves that crystalline boron inhibits Fe... 0 @C surface iron ion deposition promotes the release of iron ions in the composite material, which in turn promotes the shedding of the carbon shell on the surface of the composite material.

[0041] The above description is only a preferred embodiment of the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for degrading antibiotic pollutants using boron-carbon co-regulated nano-zero-valent iron as an activator, characterized in that, Includes the following steps: Step 1: Carbon-coated nano-zero-valent iron, denoted as Fe, is synthesized via hydrothermal and carbothermal methods. 0 @C; Step 2, take the Fe obtained in Step 1 0 @C is mixed with crystalline boron and added to wastewater containing antibiotic pollutants. Persulfate is then added as an oxidant to degrade the antibiotic pollutants.

2. The method as described in claim 1, characterized in that, In step 1, Fe 0 The preparation method of @C includes the following steps: Glucose and nano-ferric oxide were dissolved in deionized water and subjected to a hydrothermal reaction. After filtration, washing, and freeze-drying, a carbothermal reaction was carried out under a protective gas environment to obtain carbon-coated nano-zero-valent iron.

3. The method as described in claim 2, characterized in that, The molar ratio of carbon in the glucose to iron in the nano-iron oxide is (16~22):1; the hydrothermal reaction temperature is 180℃~200℃, and the reaction time is 8~10 hours; during washing, ethanol and deionized water are used respectively; the freeze-drying temperature is -40℃~-50℃, and the freeze-drying time is 4~6 hours; the carbothermal reaction temperature is 550℃~700℃, and the reaction time is 2~3 hours.

4. The method as described in claim 1, characterized in that, In step 2, Fe 0 The mass ratio of C to crystalline boron is (1~4):

1.

5. The method as described in claim 1, characterized in that, In step 2, the persulfate is sodium persulfate, potassium persulfate, or ammonium persulfate.

6. The method as described in claim 1, characterized in that, In step 2, the antibiotic contaminants are tetracyclines, sulfonamides, quinolones, macrolides, β-lactams, or chloramphenicol.

7. The method as described in claim 1, characterized in that, In step 2, the pH value of the wastewater containing antibiotic pollutants is 3 to 11, preferably 7.

8. The method as described in claim 1, characterized in that, In step 2, the amount of persulfate added is 0.5~4 mmol / L, preferably 0.5~1 mmol / L.

9. The method as described in claim 1, characterized in that, In step 2, the amount of crystalline boron fed is 0~200 mg / L, preferably 100~200 mg / L, and Fe... 0 The dosage of @C is 50~400mg / L, preferably 200~400mg / L.

10. Application of persulfate as an oxidant and carbon-coated nano-zero-valent iron synergistically crystallized boron as an activator of persulfate in the degradation of antibiotic pollutants.

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