A method for efficiently activating peroxymonosulfate to degrade ofloxacin

Abstract

This invention discloses a highly efficient method for activating peroxymonosulfate (PMS) to degrade ofloxacin. The method is characterized by employing a degradation catalytic material based on an Mxenes support, containing both Mn and N active sites, to activate PMS. The synergistic effect of the combined catalytic action of the Mn and N active sites enhances the activation efficiency of PMS, thereby achieving the degradation of ofloxacin in water. This invention reduces metal leaching, improves degradation stability, and increases the efficiency of PMS-activated ofloxacin degradation during the ofloxacin degradation process. It also boasts advantages such as simple material preparation, low cost, convenient implementation, good catalytic degradation effect on pollutants, convenient recovery, and no secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of environmental protection technology for removing antibiotics from water, specifically to a method for efficiently activating peroxymonosulfate to degrade ofloxacin. Background Technology

[0002] Ofloxacin (OFL) is a typical fluoroquinolone antibiotic, commonly used as an antibiotic for bacterial infections. However, this class of drugs has high chemical toxicity; even low concentrations of ofloxacin can induce changes in the genetic structure of bacteria, causing them to produce resistance genes, which can then spread through the water cycle. Furthermore, it can lead to the development of drug resistance and antibiotic resistance genes (ARGs) in pathogens and other microorganisms, thereby threatening human health and disrupting ecosystem stability. Therefore, it is necessary to take effective measures to remove this type of pollutant from water.

[0003] Advanced oxidation processes (AOPs) can effectively degrade antibiotics by generating highly reactive free radicals (such as hydroxyl radicals (·OH)), converting large antibiotic molecules into smaller, less toxic compounds, and even mineralizing them into non-toxic carbon dioxide (CO2) and water (H2O). Therefore, AOPs are widely used in antibiotic removal research. Among them, persulfate-activated AOPs (SR-AOPs) utilize sulfate radicals generated during persulfate activation. Hydroxyl radicals (·OH) and other reactive oxygen species (ROS) remove recalcitrant organic matter from water, exhibiting strong removal capabilities and adaptability for antibiotics. Furthermore, compared to other advanced oxidation technologies, SR-AOPs demonstrate better selectivity, longer half-lives, and a wider pH range. Therefore, SR-AOPs are frequently used to remove recalcitrant pollutants and are particularly advantageous for antibiotic removal.

[0004] Currently, the main activation methods for persulfate include thermal activation, ultraviolet light activation, alkali activation, transition metal activation, ultrasonic activation, and electroactivation. Among these, transition metal activation can achieve persulfate activation at room temperature without additional energy or chemicals, and it boasts high activation efficiency, good antibiotic removal efficacy, and generally good catalytic degradation effects. However, conventional transition metal activation degradation methods often result in the inability to recover metals, leading to serious secondary pollution.

[0005] Therefore, how to better utilize the principle of transition metal activation degradation to improve the catalytic degradation effect of ofloxacin, while reducing metal leaching, improving degradation stability, and enhancing the degradation of pollutants during the degradation process, has become a problem that needs to be considered and solved by those skilled in the art. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a highly efficient method for degrading ofloxacin by activated peroxymonosulfate, which has good degradation effect, can reduce metal leaching, improve degradation stability, and improve the efficiency of pollutant degradation.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A method for efficiently activating peroxymonosulfate to degrade ofloxacin is characterized by employing a degradation catalytic material based on Mxenes carrier, containing both Mn and N active sites, to activate peroxymonosulfate. The synergistic effect of the co-catalysis by the Mn and N active sites enhances the activation effect of peroxymonosulfate, thereby achieving the degradation of ofloxacin in water.

[0009] Thus, because the degradation catalytic material used in this method contains both Mn and N active sites, the characterization results show that the Mn and N active sites are tightly bound to the Mxenes support, loaded on the surface of the MXenes and embedded in the interlayer, giving it a larger specific surface area and pore volume, and the presence of oxygen vacancies that are conducive to the activation of peroxymonosulfate, further accelerating the reaction rate of ofloxacin degradation.

[0010] Furthermore, this method first prepares an accordion-shaped Mxenes material as a carrier, and introduces it into the interior of the Mxenes material by adding Mn and N precursors; then, Mn-N active sites are loaded by chemical bonding to obtain a two-dimensional layered ofloxacin degradation catalytic material; finally, the prepared ofloxacin degradation catalytic material and peroxymonosulfate are added to the water containing ofloxacin to be degraded, and the ofloxacin degradation catalytic material is used to activate the peroxymonosulfate to achieve the degradation of ofloxacin.

[0011] Thus, this method utilizes Mxenes as a support. Mxenes are two-dimensional inorganic compounds with characteristics such as high specific surface area, environmental friendliness, abundant functional groups, ease of functionalization, high metallic conductivity, and hydrophilicity. Furthermore, MXenes possess a unique layered structure and two-dimensional morphology, offering significant flexibility. The metal oxides supported on two-dimensional MXenes increase the number of active metal sites, improve conductivity, and facilitate the generation of active substances. The coordination interactions between the multi-metal and functional groups on the MXene surface accelerate the redox cycle reactions between metal ions, promoting electron transfer and significantly improving catalytic activation and the degradation efficiency of organic pollutants. In addition, the transition metal structure supported on two-dimensional MXenes exhibits good stability, greatly reducing metal ion leaching.

[0012] Therefore, in this method, a degradation catalytic material with Mn-N active sites loaded by chemical bonding is used as a support for MXenes. This not only improves the activation effect and reduces the leaching of metal ions, but also allows the Ti metal element contained in the MXenes support to transform into more free radicals between Ti(II) and Ti(III), thereby enhancing the degradation of ofloxacin.

[0013] Furthermore, the ofloxacin degradation catalytic material is mainly composed of Ti3C2T. x Using Mxenes as the matrix, porous two-dimensional layered structures are formed by loading Mn and N elements to create Mn-O and NO structural configurations. The chemical formula can be characterized as Mn-U. 2.5 @MXenes 1.0 .

[0014] Thus, because the Ti element in the accordion-shaped MXenes support combines with oxygen to form Ti-O bonds, while manganese ions and nitrogen elements also bond with oxygen elements, and oxygen elements bond with Ti elements in the support, these interconnected rings form a two-dimensional layered metal framework structure, resulting in a Mn / NO-Ti structure. This structure shows that the Mn-N sites loaded on the MXenes are connected by oxygen elements as intermediate bridges, consistent with XPS detection results. Furthermore, since the two-dimensional layered catalytic degradation catalytic material of this application is obtained through the pyrolysis of the accordion-shaped MXenes, the precursor loses a large amount of oxygen and hydrogen elements during the pyrolysis reaction, creating numerous oxygen vacancies in the precursor. Combined with the Mn-N site configuration, which exists in the form of NO or Mn-O, this allows more reaction sites to be embedded or attached within the MXenes material. This not only provides excellent adsorption performance but also fixes the active sites, enhancing the stability during the catalytic degradation process and significantly reducing the leaching of metal ions. Furthermore, both the supported Mn metal and the Ti metal in the MXenes material can provide a variety of positively valenced metal ions for activating PMS (peroxymonosulfate), which is more conducive to improving the activation effect and efficiency. Meanwhile, the two-dimensional layered catalytic degradation material generated in this application has a CN / CO configuration, which allows more active sites to be fully exposed, thereby improving catalytic activity.

[0015] From the perspective of the chemical reaction process, the reason why this experiment achieved the activation of peroxymonosulfate to degrade ofloxacin is that peroxymonosulfate has a weak ability to degrade ofloxacin. However, the ofloxacin degradation catalytic material prepared in this experiment (which can be characterized as Mn-U) 2.5 @MXenes 1.0Where Mn represents the Mn site in the catalytic material; U represents the N site in the catalytic material; 2.5 represents the mass ratio of MnCl2·4H2O:urea during the preparation process; @MXenes 1.0 This indicates that MXenes (supported by MXenes) has a certain adsorption effect on ofloxacin. Further mixing with degradation catalysts and peroxymonosulfate resulted in the formation of Mn-U... 2.5 @MXenes 1.0 Activating the peroxymonosulfate system can generate sulfate free radicals. Hydroxyl radical (·OH), superoxide radical Singlet oxygen 1 O2 and other reactive oxygen species work together to degrade adsorbed (and unadsorbed) ofloxacin. The catalytic degradation material Mn-U prepared in this experiment... 2.5 @MXenes 1.0 With its two-dimensional layered porous structure, large specific surface area, and CN / CO configuration, Mn-U allows for the full exposure of more active sites, thereby enhancing catalytic activity. 2.5 @MXenes 1.0 The active site is a Mn / N diatomic pair, giving the catalyst a strong electron transfer capability. Firstly, the Ti atoms within the precursor MXenes can catalyze the formation of peroxymonosulfate. And ·OH, and Ti(II) and Ti(III) can interconvert to generate more free radicals to degrade ofloxacin. Then, the active site Mn atom can activate peroxymonosulfate to produce ·OH、 Free radicals; and different valence states of metallic Mn can interconvert to generate more free radicals, enhancing the degradation of ofloxacin. Furthermore, unlike most materials that generate free radicals by capturing dissolved oxygen in water... The difference is that, due to Mn-U 2.5 @MXenes 1.0 It has abundant oxygen vacancies, and can produce peroxymonosulfate by activating these oxygen vacancies. This greatly enhanced The amount produced and the utilization rate of peroxymonosulfate.

[0016] Furthermore, the ofloxacin degradation catalytic material is prepared according to the following steps:

[0017] a. Immerse Ti3AlC2 in the corresponding amount of hydrofluoric acid at a ratio of 10 ml per gram, stir and mix evenly at room temperature and react.

[0018] The suspension obtained by b was repeatedly centrifuged and dehydrated and washed with pure water until the pH of the supernatant was greater than 6.

[0019] c. The dehydrated precipitate was dried to obtain accordion-shaped Ti3C2T x Mxenes vector.

[0020] The obtained Mxenes support was pyrolyzed at high temperature, and Mn and N reactive sites were loaded through chemical bonding to generate a two-dimensional layered degradation catalytic material (also known as Mn-U). 2.5 @Mxenes 1.0 ).

[0021] Furthermore, in step a, the mixture is stirred for 20 hours to ensure the reaction is effective.

[0022] Furthermore, in step b, the resulting suspension is centrifuged at 3500 rpm for 5 minutes each time to dehydrate before washing. This ensures effective dehydration and washing.

[0023] Furthermore, in step c, drying is carried out at 60°C for 24 hours. This ensures effective drying without damaging the carrier structure.

[0024] Furthermore, step d is performed at a high temperature of 120°C to ensure the reaction is effective.

[0025] Further, step d includes: 1) adding the two raw materials in proportion to 30 mL of DMF (N,N-dimethylformamide) for every 0.3 g MnCl2·4H2O and mixing and stirring to dissolve them; (this is to introduce Mn active sites into the catalytic material, and the addition of DMF promotes the reaction rate of the preparation process);

[0026] 2) Add 10 mL of ethanol, 5 mL of pure water, and urea in the corresponding proportions, with the mass ratio of MnCl2·4H2O to urea being 1:(1.5-3). (In practice, the mass ratios of the two are 1.5, 1:2, 1:2.5, and 1:3 to form four different comparative experimental examples.) This is to introduce N active sites in the catalytic material and to prepare different proportions of catalytic material for subsequent experiments.

[0027] 3) Add 0.3g of MXenes material in the corresponding proportion, stir and mix evenly (preferably by mechanical stirring for 60 minutes followed by ultrasonic vibration for 5 minutes to better promote thorough mixing);

[0028] 4) The mixture is kept at 120°C for 12 hours to complete the loading reaction (preferably in a high-pressure reactor lined with polytetrafluoroethylene). After cooling to room temperature, it is centrifuged to remove water and repeatedly washed and dried to obtain the degradation catalyst material. (Preferably, centrifugation at 3500 r / min for 5 min is performed for dehydration, followed by washing with pure water and ethanol three times each to complete the repeated washing. The resulting precipitate is then dried at 80°C for 24 hours to complete the drying process, in order to maximize the cleaning and collection of the catalyst material and remove any possible residual solvent or reaction byproducts.)

[0029] In this way, Mn and N elements are introduced into MXenes as precursors and combine with oxygen atoms, resulting in a better Mn / NO structural configuration. Furthermore, this treatment method also allows the metallic Ti element contained in the MXenes support to better combine with oxygen elements to form Ti-O bonds. Therefore, this method enables the efficient and rapid preparation of pure catalytic materials.

[0030] Thus, in the above steps, Mn-U is first prepared using a hydrothermal method. 2.5 @Mxenes 1.0 The hydrothermal method provides a suitable reaction space for the degradation catalyst material, ensuring a uniformly dispersed environment conducive to the reaction. Subsequently, the resulting MXenes product is pyrolyzed. Pyrolysis transforms the organic framework into a two-dimensional layered support, further reducing metal ion leaching and preventing secondary contamination of the material.

[0031] The advantage of this precursor Mxenes lies in its distinct two-dimensional layered structure, which allows Mn-N particle clusters to tightly bind with MXenes, loading them on the MXenes surface and embedding them in the interlayer. This results in a larger specific surface area and pore volume, and the presence of oxygen vacancies conducive to PMS activation. Simultaneously, pyrolysis causes the organic framework to lose a large amount of oxygen and hydrogen, creating numerous oxygen vacancies and increasing the activation degree with PMS. The oxygen vacancies generated by pyrolysis provide the catalyst with multiple active sites. The Mn and N reactive sites and oxygen vacancies in the catalyst facilitate the full utilization of PMS, reducing resource waste. Furthermore, oxygen vacancies generate singlet oxygen and superoxide radicals, improving the degradation efficiency of ofloxacin. Therefore, the catalytic material of this invention effectively reduces metal ion leaching and promotes metal ion participation in the catalytic reaction, with a large number of Mn-N reactive sites loaded in the interlayer of MXenes, enhancing PMS activation efficiency.

[0032] Furthermore, during degradation, the prepared ofloxacin degradation catalyst is first added to the water body to be degraded and mixed evenly, and then peroxymonosulfate is added to the water body to be degraded and mixed evenly to complete the degradation reaction.

[0033] This is because the two-dimensional layered degradation catalyst material itself is a porous adsorbent with strong adsorption properties. Adding this material first and mixing it thoroughly with the water to be degraded allows some of the ofloxacin to be adsorbed into the pores of the catalyst material. Then, adding persulfate occurs because a catalytic activation reaction occurs between the catalyst material and the persulfate, naturally attracting the persulfate. This activation of the persulfate allows for more efficient degradation of ofloxacin. Furthermore, the MXenes carrier has good hydrophilicity, further improving the degradation efficiency and effectiveness.

[0034] Furthermore, during degradation, the ratio of the ofloxacin degradation catalyst and peroxymonosulfate is such that for every 0.01g of ofloxacin in the water, 0.2g of ofloxacin degradation catalyst and 0.5g of peroxymonosulfate are added.

[0035] This data represents the optimal ratio for verifying the degradation effect. Specifically, the applicant determined the optimal amount of catalyst material through preliminary experiments. First, 100 mL of ofloxacin solution with a concentration of 10 mg / L was added to a 250 mL beaker; PMS was prepared as a 1 g / L solution, and the dosage of catalyst Mn-U@MXenes was 0.2 g / L. The mass of Mn raw material (i.e., MnCl2·4H2O) and MXenes was kept constant during the experiment, which was conducted at room temperature (25℃) without adjusting the pH or changing the mass ratio of urea.

[0036] Specifically, the process of activating peroxymonosulfate with the ofloxacin degradation catalytic material of the present invention includes the following reaction:

[0037]

[0038]

[0039]

[0040]

[0041]

[0042]

[0043]

[0044]

[0045]

[0046]

[0047]

[0048] Furthermore, after the degradation reaction is completed, the used ofloxacin degradation catalyst material is regenerated. First, the material is washed three times with deionized water. Then, the washed material is soaked in ethanol for 2 hours. Next, it is centrifuged and washed three times with ethanol. Finally, it is washed three times with deionized water and placed in an oven at 60°C for 12 hours to achieve recycling.

[0049] This is because, with increasing reaction times, both the degradation rate and reaction rate constant of the catalytic degradation material for ofloxacin decrease. This is likely due to the reduction in Mn-N active sites and pore blockage, leading to a decrease in the reaction rate constant for persulfate. Therefore, during regeneration, three washes with deionized water are performed to remove impurities or residues from the material surface; soaking in ethanol for 2 hours further cleans the surface and helps remove moisture; after centrifugation, three washes with ethanol further remove impurities; finally, three washes with deionized water followed by drying in a 60°C oven for 12 hours completely removes any remaining moisture, ensuring accuracy and stability for subsequent experiments. These steps are necessary to regenerate the Mn-N active sites. 2.5 @Mxenes 1.0 The degradation catalyst material remains clean and pure, providing a stable foundation for subsequent methods. Subsequent experiments show that the ofloxacin degradation catalyst material prepared in this invention can be easily and quickly recycled while still exhibiting good catalytic degradation performance, thus significantly reducing material costs.

[0050] Therefore, compared with other catalysts, the advantages of this method are low metal leaching, good catalytic performance, and the ability to create a large number of Mn-N reaction sites by utilizing the precursor MXenes itself, which improves the reaction rate of ofloxacin degradation. The organic framework can be converted into a support by utilizing the precursor itself under pyrolysis conditions, thus saving raw materials.

[0051] In summary, this invention can reduce metal leaching, improve degradation stability, and increase the efficiency of activated PMS in degrading of ofloxacin during the degradation process. It has the advantages of simple material preparation method, low cost, convenient implementation, good catalytic degradation effect on pollutants, convenient recycling, and no secondary pollution. Attached Figure Description

[0052] Figure 1 A schematic diagram illustrating the performance analysis of PMS activation for ofloxacin degradation using degradation catalytic materials prepared with different urea ratios.

[0053] Figure 2A schematic diagram illustrating the performance analysis of PMS degradation of ofloxacin using degradation catalysts prepared with different MXene pairing ratios.

[0054] Figure 3 Scanning electron microscope images and elemental distribution diagrams before and after the preparation of degradation catalytic materials.

[0055] Figure 4 The X-ray diffraction patterns are shown before and after the preparation process of the degradation catalytic material.

[0056] Figure 5 A schematic diagram of the infrared spectra (FTIR) of the catalyst material before and after the reaction for degradation.

[0057] Figure 6 This is a schematic diagram of the nitrogen adsorption-desorption isotherm (BET) curve for the degradation catalyst material.

[0058] Figure 7 This is a schematic diagram comparing the degradation rate and degradation reaction rate constant of ofloxacin in different systems.

[0059] Figure 8 For the degradation catalytic material Mn-U 2.5 @Mxenes 1.0 A schematic diagram of a cyclic experiment for the degradation of ofloxacin by activated PMS. Detailed Implementation

[0060] The present invention will now be described in further detail with reference to the accompanying drawings.

[0061] Optimal Implementation Method: A method for efficiently activating peroxymonosulfate to degrade ofloxacin, characterized in that the method uses a degradation catalytic material based on Mxenes carrier, containing both Mn and N active sites, to activate peroxymonosulfate. The synergistic effect of the co-catalysis of Mn and N active sites is utilized to improve the activation effect of peroxymonosulfate and achieve the degradation of ofloxacin in water.

[0062] Thus, because the degradation catalytic material used in this method contains both Mn and N active sites, the characterization results show that the Mn and N active sites are tightly bound to the Mxenes support, loaded on the surface of the MXenes and embedded in the interlayer, giving it a larger specific surface area and pore volume, and the presence of oxygen vacancies that are conducive to the activation of peroxymonosulfate, further accelerating the reaction rate of ofloxacin degradation.

[0063] Specifically, this method first prepares an accordion-shaped Mxenes material as a carrier, and introduces it into the interior of the Mxenes material by adding Mn and N precursors; then, Mn-N active sites are loaded by chemical bonding to obtain a two-dimensional layered ofloxacin degradation catalytic material; finally, the prepared ofloxacin degradation catalytic material and peroxymonosulfate are added to the water containing ofloxacin to be degraded, and the ofloxacin degradation catalytic material is used to activate the peroxymonosulfate to achieve the degradation of ofloxacin.

[0064] Thus, this method utilizes Mxenes as a support. Mxenes are two-dimensional inorganic compounds with characteristics such as high specific surface area, environmental friendliness, abundant functional groups, ease of functionalization, high metallic conductivity, and hydrophilicity. Furthermore, MXenes possess a unique layered structure and two-dimensional morphology, offering significant flexibility. The metal oxides supported on two-dimensional MXenes increase the number of active metal sites, improve conductivity, and facilitate the generation of active substances. The coordination interactions between the multi-metal and functional groups on the MXene surface accelerate the redox cycle reactions between metal ions, promoting electron transfer and significantly improving catalytic activation and the degradation efficiency of organic pollutants. In addition, the transition metal structure supported on two-dimensional MXenes exhibits good stability, greatly reducing metal ion leaching.

[0065] Therefore, in this method, a degradation catalytic material with Mn-N active sites loaded by chemical bonding is used as a support for MXenes. This not only improves the activation effect and reduces the leaching of metal ions, but also allows the Ti metal element contained in the MXenes support to transform into more free radicals between Ti(II) and Ti(III), thereby enhancing the degradation of ofloxacin.

[0066] In this embodiment, the ofloxacin degradation catalytic material is mainly composed of Ti3C2T. x Using Mxenes as the matrix, porous two-dimensional layered structures are formed by loading Mn and N elements to create Mn-O and NO structural configurations. The chemical formula can be characterized as Mn-U. 2.5 @MXenes 1.0 .

[0067] Thus, because the Ti element in the accordion-shaped MXenes support combines with oxygen to form Ti-O bonds, while manganese ions and nitrogen elements also bond with oxygen elements, and oxygen elements bond with Ti elements in the support, these interconnected rings form a two-dimensional layered metal framework structure, resulting in a Mn / NO-Ti structure. This structure shows that the Mn-N sites loaded on the MXenes are connected by oxygen elements as intermediate bridges, consistent with XPS detection results. Furthermore, since the two-dimensional layered catalytic degradation catalytic material of this application is obtained through the pyrolysis of the accordion-shaped MXenes, the precursor loses a large amount of oxygen and hydrogen elements during the pyrolysis reaction, creating numerous oxygen vacancies in the precursor. Combined with the Mn-N site configuration, which exists in the form of NO or Mn-O, this allows more reaction sites to be embedded or attached within the MXenes material. This not only provides excellent adsorption performance but also fixes the active sites, enhancing the stability during the catalytic degradation process and significantly reducing the leaching of metal ions. Furthermore, both the supported Mn metal and the Ti metal in the MXenes material can provide a variety of positively valenced metal ions for activating PMS (peroxymonosulfate), which is more conducive to improving the activation effect and efficiency. Meanwhile, the two-dimensional layered catalytic degradation material generated in this application has a CN / CO configuration, which allows more active sites to be fully exposed, thereby improving catalytic activity.

[0068] From the perspective of the chemical reaction process, the reason why this experiment achieved the activation of peroxymonosulfate to degrade ofloxacin is that peroxymonosulfate has a weak ability to degrade ofloxacin. However, the ofloxacin degradation catalytic material prepared in this experiment (which can be characterized as Mn-U) 2.5 @MXenes 1.0 Where Mn represents the Mn site in the catalytic material; U represents the N site in the catalytic material; 2.5 represents the mass ratio of MnCl2·4H2O:urea during the preparation process; @MXenes 1.0 This indicates that MXenes (supported by MXenes) has a certain adsorption effect on ofloxacin. Further mixing with degradation catalysts and peroxymonosulfate resulted in the formation of Mn-U... 2.5 @MXenes 1.0 Activating the peroxymonosulfate system can generate sulfate free radicals. Hydroxyl radical (·OH), superoxide radical Singlet oxygen 1 O2 and other reactive oxygen species work together to degrade adsorbed (and unadsorbed) ofloxacin. The catalytic degradation material Mn-U prepared in this experiment... 2.5 @MXenes 1.0With its two-dimensional layered porous structure, large specific surface area, and CN / CO configuration, Mn-U allows for the full exposure of more active sites, thereby enhancing catalytic activity. 2.5 @MXenes 1.0 The active site is a Mn / N diatomic pair, giving the catalyst a strong electron transfer capability. Firstly, the Ti atoms within the precursor MXenes can catalyze the formation of peroxymonosulfate. And ·OH, and Ti(II) and Ti(III) can interconvert to generate more free radicals to degrade ofloxacin. Then, the active site Mn atom can activate peroxymonosulfate to produce ·OH、 Free radicals; and different valence states of metallic Mn can interconvert to generate more free radicals, enhancing the degradation of ofloxacin. Furthermore, unlike most materials that generate free radicals by capturing dissolved oxygen in water... The difference is that, due to Mn-U 2.5 @MXenes 1.0 It has abundant oxygen vacancies, and can produce peroxymonosulfate by activating these oxygen vacancies. This greatly enhanced The amount produced and the utilization rate of peroxymonosulfate.

[0069] In practice, the ofloxacin degradation catalytic material is prepared according to the following steps:

[0070] a. Immerse Ti3AlC2 in the corresponding amount of hydrofluoric acid at a ratio of 10 mL per gram, stir and mix evenly at room temperature and react.

[0071] The suspension obtained by b was repeatedly centrifuged and dehydrated and washed with pure water until the pH of the supernatant was greater than 6.

[0072] c. The dehydrated precipitate was dried to obtain accordion-shaped Ti3C2T x Mxenes vector.

[0073] The obtained Mxenes support was pyrolyzed at high temperature, and Mn and N reactive sites were loaded through chemical bonding to generate a two-dimensional layered degradation catalytic material (also known as Mn-U). 2.5 @Mxenes 1.0 ).

[0074] During implementation, stir for 20 hours in step a to ensure the reaction effect.

[0075] In practice, in step b, the resulting suspension is centrifuged at 3500 rpm for 5 minutes each time to dehydrate before washing. This ensures effective dehydration and washing.

[0076] During implementation, in step c, drying is carried out at 60℃ for 24 hours. This ensures effective drying without damaging the carrier structure.

[0077] During implementation, the high-temperature environment for step d is 120℃ to ensure the reaction effect.

[0078] During implementation, step d includes: 1) Adding the two raw materials to 30 mL of DMF (N,N-dimethylformamide) according to the ratio of 0.3 g MnCl2·4H2O and mixing and stirring to dissolve them;

[0079] 2) Add 10 mL of ethanol, 5 mL of pure water, and urea in the corresponding proportions, with the mass ratio of MnCl2·4H2O to urea being 1:(1.5-3). In subsequent experiments, the mass ratios of the two materials will be 1.5, 1:2, 1:2.5, and 1:3 to form four different comparative test cases. This preparation of different proportions of catalyst materials is to prepare for subsequent experiments.

[0080] 3) Add 0.3g of MXenes material in the corresponding proportion, stir and mix evenly. It is preferable to use mechanical stirring for 60 minutes followed by ultrasonic vibration for 5 minutes to better promote thorough mixing.

[0081] 4) The mixture was kept at 120℃ for 12 hours to complete the loading reaction (in practice, this was carried out in a high-pressure reactor lined with polytetrafluoroethylene). After cooling to room temperature, it was centrifuged to dehydrate and repeatedly washed and dried to obtain the degradation catalyst material. In practice, centrifugation was performed at 3500 r / min for 5 min for dehydration, followed by washing with pure water and ethanol three times each. The resulting precipitate was then dried at 80℃ for 24 hours to complete the drying process, in order to maximize the cleaning and collection of the catalyst material and remove any possible residual solvent or reaction byproducts.

[0082] In this way, Mn and N elements are introduced into MXenes as precursors and combine with oxygen atoms, resulting in a better Mn / NO structural configuration. Furthermore, this treatment also allows the metallic Ti element contained in the MXenes support to better combine with oxygen elements to form Ti-O bonds.

[0083] Thus, in the above steps, Mn-U is first prepared using a hydrothermal method. 2.5 @Mxenes 1.0 The hydrothermal method provides a suitable reaction space for the degradation catalyst material, ensuring a uniformly dispersed environment conducive to the reaction. Subsequently, the resulting MXenes product is pyrolyzed. Pyrolysis transforms the organic framework into a two-dimensional layered support, further reducing metal ion leaching and preventing secondary contamination of the material.

[0084] The advantage of this precursor Mxenes lies in its distinct two-dimensional layered structure, which allows Mn-N particle clusters to tightly bind with MXenes, loading them on the MXenes surface and embedding them in the interlayer. This results in a larger specific surface area and pore volume, and the presence of oxygen vacancies conducive to PMS activation. Simultaneously, pyrolysis causes the organic framework to lose a large amount of oxygen and hydrogen, creating numerous oxygen vacancies and increasing the activation degree with PMS. The oxygen vacancies generated by pyrolysis provide the catalyst with multiple active sites. The Mn and N reactive sites and oxygen vacancies in the catalyst facilitate the full utilization of PMS, reducing resource waste. Furthermore, oxygen vacancies generate singlet oxygen and superoxide radicals, improving the degradation efficiency of ofloxacin. Therefore, the catalytic material of this invention effectively reduces metal ion leaching and promotes metal ion participation in the catalytic reaction, with a large number of Mn-N reactive sites loaded in the interlayer of MXenes, enhancing PMS activation efficiency.

[0085] In this embodiment, during degradation, the prepared ofloxacin degradation catalyst is first added to the water to be degraded and mixed evenly, and then peroxymonosulfate is added to the water to be degraded and mixed evenly to complete the degradation reaction.

[0086] This is because the two-dimensional layered degradation catalyst material itself is a porous adsorbent with strong adsorption properties. Adding this material first and mixing it thoroughly with the water to be degraded allows some of the ofloxacin to be adsorbed into the pores of the catalyst material. Then, adding persulfate occurs because a catalytic activation reaction occurs between the catalyst material and the persulfate, naturally attracting the persulfate. This activation of the persulfate allows for more efficient degradation of ofloxacin. Furthermore, the MXenes carrier has good hydrophilicity, further improving the degradation efficiency and effectiveness.

[0087] In this embodiment, during degradation, the ratio of the ofloxacin degradation catalyst and peroxymonosulfate is such that 0.2g of ofloxacin degradation catalyst and 0.5g of peroxymonosulfate are added for every 0.01g of ofloxacin in the water.

[0088] This data represents the optimal ratio for verifying the degradation effect. Specifically, the applicant determined the optimal amount of catalyst material through preliminary experiments. First, 100 mL of ofloxacin solution with a concentration of 10 mg / L was added to a 250 mL beaker; PMS was prepared as a 1 g / L solution, and the dosage of catalyst Mn-U@MXenes was 0.2 g / L. The mass of Mn raw material (i.e., MnCl2·4H2O) and MXenes was kept constant during the experiment, which was conducted at room temperature (25℃) without adjusting the pH or changing the mass ratio of urea.

[0089] Specifically, the process of activating peroxymonosulfate with the ofloxacin degradation catalytic material of the present invention includes the following reaction:

[0090]

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[0092]

[0093]

[0094]

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[0096]

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[0101] In this embodiment, after the degradation reaction is completed, the used ofloxacin degradation catalyst material is regenerated. First, the material is washed three times with deionized water. Then, the washed material is soaked in ethanol for 2 hours. Next, it is centrifuged and washed three times with ethanol. Finally, it is washed three more times with deionized water and placed in an oven at 60°C for 12 hours to achieve recycling.

[0102] This is because, with increasing reaction times, both the degradation rate and reaction rate constant of the catalytic degradation material for ofloxacin decrease. This is likely due to the reduction in Mn-N active sites and pore blockage, leading to a decrease in the reaction rate constant for persulfate. Therefore, during regeneration, three washes with deionized water are performed to remove impurities or residues from the material surface; soaking in ethanol for 2 hours further cleans the surface and helps remove moisture; after centrifugation, three washes with ethanol further remove impurities; finally, three washes with deionized water followed by drying in a 60°C oven for 12 hours completely removes any remaining moisture, ensuring accuracy and stability for subsequent experiments. These steps are necessary to regenerate the Mn-N active sites. 2.5 @Mxenes 1.0The degradation catalyst material remains clean and pure, providing a stable foundation for subsequent methods. Subsequent experiments show that the ofloxacin degradation catalyst material prepared in this invention can be easily and quickly recycled while still exhibiting good catalytic degradation performance, thus significantly reducing material costs.

[0103] Therefore, compared with other catalysts, the advantages of this method are low metal leaching, good catalytic performance, and the ability to create a large number of Mn-N reaction sites by utilizing the precursor MXenes itself, which improves the reaction rate of ofloxacin degradation. The organic framework can be converted into a support by utilizing the precursor itself under pyrolysis conditions, thus saving raw materials.

[0104] See Figure 1-8 To further study and verify the process and principle of this method, the applicant conducted further experimental verification and analysis on the principle and effect of this application based on the steps of the above specific implementation.

[0105] First, the applicant conducted an experimental study on the degradation effect of the degradation catalytic materials obtained during material preparation for different urea pairing ratios in the above-mentioned specific implementation process. (See [link to relevant documentation]). Figure 1 As shown, the applicant conducted ofloxacin degradation experiments by keeping the mass of Mn raw material (i.e., MnCl2·4H2O) and MXenes constant, while changing the mass ratio of urea. The results showed... Figure 1 As shown in (a), when the amount of urea used is 0.75g (i.e., Mn-U), 2.5 @MXenes 1.0 ) and 0.60g (i.e., Mn-U 2.0 @MXenes 1.0 The removal rate of ofloxacin reached over 90%; and Mn-U 2.5 @MXenes 1.0 The removal rate was even higher (95.81%). Also, see... Figure 1 (b) shows that, based on the ofloxacin adsorption experiment within 1 hour, when Mn-U is used... 2.5 @MXenes 1.0 At that time, the adsorption removal rate of ofloxacin was only 25.60%; using Mn-U 2.0 @MXenes 1.0 The adsorption removal rate of ofloxacin reached 39.13%. This indicates that when the urea dosage is 0.60g, the removal rate of ofloxacin is largely due to the adsorption effect of the material, rather than the degradation effect of ROS generated by activated PMS, which is not conducive to the conversion of OFL to small molecule organic compounds or even the mineralization of OFL. Therefore, it is concluded that a urea dosage of 0.75g is the optimal ratio (i.e., Mn-U). 2.5 @MXenes 1.0 ).

[0106] Figure 2 Performance analysis of PMS degradation of ofloxacin using catalytic materials prepared with different MXene pairing ratios. The applicant further investigated the effect of the MXene pairing ratio on the removal and adsorption performance of ofloxacin. In experiments groups a and b, the amounts of Mn and urea were kept constant at 0.30 g and 0.75 g, respectively, while the amount of MXene was varied. The results showed that the removal efficiency of OFL within 1 h differed significantly when the MXene amounts were 0.15 g, 0.30 g, and 0.45 g. The OFL removal efficiency with 0.30 g of MXene was significantly better than the other two groups, and the adsorption efficiencies of the three groups were similar. Therefore, the optimal catalytic material should be selected with a mass ratio of 0.3 g of MnCl2·4H2O, 0.75 g of urea, and 0.30 g of MXene (i.e., Mn-U). 2.5 @MXenes 1.0 ).

[0107] Figure 3 Electron microscopy was used to analyze the surface structure and elemental composition of the catalytic material. Figure 3 (a) A scanning electron microscope (SEM) diagram of the Mxenes support prepared by the reaction of Ti3AlC2 and hydrofluoric acid. As shown in the figure, it exhibits a two-dimensional layered structure with clear interlayer spacing, indicating that the prepared Mxenes has good etching properties, which is conducive to the subsequent preparation of Mn-U 2.5 @MXenes 1.0 It provided favorable conditions. Figure 3 Images (b)-(c) show the Mn-N reactive sites attached to the MXenes material; the scanning electron microscope (SEM) images are at 500 nm and 200 nm, respectively. Based on the images, the catalytic material Mn-N... 2.5 @MXenes 1.0 Successfully prepared. Compared with MXenes, Mn-U prepared by hydrothermal method... 2.5 @MXenes 1.0 Mn-N particles were successfully attached to the surface of the material, and Mn-N particles were also embedded between the layered structures, thanks to the sandwich-like structure of MXenes. Figure 3 (d) is Mn-U 2.5 @MXenes 1.0 This is an overall elemental distribution diagram of EDS. The diagram shows that the prepared catalytic material widely contains five elements: Ti, Mn, C, N, and O. Furthermore, these five elements are distributed across the Mn-U range. 2.5 @MXenes 1.0 The uniform distribution of Mn-N particles indicates that the Mn-N particles (i.e., the reactive sites) are well distributed in the catalyst.

[0108] Figure 3(e)-(f) represent the catalysts Mn-U, respectively. 2.5 @MXenes 1.0 Distribution images of Ti, Mn, C, N, and O under EDS characterization.

[0109] Figure 4 The X-ray diffraction patterns are shown before and after the preparation of the degradation catalyst material. XRD analysis was performed on MXenes and Mn-U. 2.5 @MXenes 1.0 The crystal structures of Mn-U were compared. Compared to MXenes, Mn-U... 2.5 @MXenes 1.0 Several new peaks appeared. Among them, Mn-U 2.5 @MXenes 1.0 The peaks at 14.60°, 29.43°, 30.97°, 43.04°, and 52.99° correspond to the (002), (004), (111), (020), and (024) crystal planes of Mn3N2 (JCPDS No. 47-1465), indicating the successful formation of manganese-nitrogen sites. Meanwhile, the Mn-U... 2.5 @MXenes 1.0 The peaks at 17.55°, 28.87°, 34.06°, 35.74°, 41.58°, 51.59°, and 60.11° correspond to the (111), (220), (311), (222), (400), (422), and (440) crystal planes of Mn3O4 (JCPDS No. 04-0732). Furthermore, Mn-U 2.5 @MXenes 1.0 The characteristic peaks at 17.37° (020), 26.67° (120), 36.36° (021), 38.35° (111), 43.72° (050), and 52.55° (201) conform to MnO (JCPDS No. 04-0326). These results all indicate that Mn-U 2.5 @MXenes 1.0 The successful preparation of [catalyst name missing] demonstrates that the generation of manganese and nitrogen sites enhances the activation of PMS through reaction sites. Furthermore, the oxidation-reduction reaction between metals facilitates the cycling of metal valence states, promoting PMS activation and generating more free radicals, thus achieving efficient degradation of ofloxacin. This will benefit future researchers in developing catalysts with superior performance based on structure and different metal configurations.

[0110] Figure 5 FTIR spectroscopy analysis was performed on the degradation catalyst material before and after the reaction. Mn-U 2.5 @MXenes 1.0 Spectral images such as Figure 5As shown. MXenes at 3408 cm -1 2924cm -1 and 1119cm -1 The peaks represent -OH, CH, and COC, respectively. Meanwhile, due to the stretching vibration of C=O, MXenes show a peak at 1635 cm⁻¹. -1 Characteristic peaks were also observed nearby. Similar to MXenes, -OH, CH, C=O, and COC also appeared in the FTIR spectrum of Mn-U2.5@MXenes1.0, but some functional groups were shifted to a certain extent relative to MXenes, which may be due to slight bond disorder caused by the catalyst recombination process.

[0111] Figure 6 The image shows the nitrogen adsorption-desorption isotherm (BET) curves for the degradation catalyst material. Figure 6 As shown, MXenes and Mn-U2.5@MXenes1.0 conform to type IV isotherms with hysteresis lines at P / P0 = 0.4-1.0, indicating that they have a mesoporous structure. The results show that Mn-U... 2.5 @MXenes 1.0 It exhibits a significantly larger specific surface area and pore volume, which is likely due to structural modification caused by Mn particle doping, indicating that Mn-U 2.5 @MXenes 1.0 Successfully prepared. Furthermore, the larger specific surface area facilitates the exposure of active sites, thereby enhancing the catalyst's adsorption and removal efficiency for ofloxacin and its PMS activation performance.

[0112] Figure 7 The figures (a) and (b) show the degradation rate of ofloxacin in different systems. Figure 7 (a) shows that the removal of ofloxacin by persulfate alone is mainly concentrated in the first 20 minutes (degradation rate of 14.49%). The removal capacity significantly weakens from 20 to 90 minutes, with the OFL degradation rate increasing to only 21.81% by 90 minutes (an increase of 7.32% after 70 minutes), indicating that the oxidative degradation capacity of persulfate for ofloxacin is limited. MXenes and Mn-U 2.5 @MXenes 1.0 The system achieved adsorption and removal rates of ofloxacin of 14.07% and 21.45% within 10 min, respectively, and of 16.27% (an increase of only 2.20%) and 30.77% (an increase of only 9.32%) at 90 min. This indicates that MXenes and Mn-U 2.5 @MXenes 1.0 A relatively balanced adsorption state can be reached in about 10 minutes, and this result also indicates that Mn-U 2.5 @MXenes1.0 The adsorption performance of ofloxacin was superior to that of MXenes. In the MXenes / PMS system, the removal rate of OFL was 65.99% at 60 min, and only 71.32% at 90 min. However, Mn-U 2.5 @MXenes 1.0 The PMS system removed 95.81% of ofloxacin within 60 minutes (96.07% within 90 minutes). This indicates that Mn-U 2.5 @MXenes 1.0 It plays a crucial role in the activation of persulfate and the degradation of ofloxacin, attributed to Mn-U 2.5 @MXenes 1.0 It possesses abundant Mn-N active sites and a unique two-dimensional layered structure. Furthermore, such as... Figure 7 (b) shows PMS, MXenes, and Mn-U alone. 2.5 @MXenes 1.0 MXenes / PMS and Mn-U 2.5 @MXenes 1.0 The reaction rate constant (k) of the / PMS system obs The values ​​were 0.0088 min. -1 0.0172min -1 0.0264min -1 0.0769min -1 and 0.2031min -1 Compared to the systems of persulfate and MXenes alone, the calculated synergistic index of the MXenes / PMS system was 2.96, indicating a synergistic effect between PMS and MXenes. However, compared to PMS and Mn-U alone... 2.5 @MXenes 1.0 System, Mn-U 2.5 @MXenes 1.0 The synergy index of the PMS / Mn-U system was 5.77 (nearly twice that of the MXenes / PMS system), indicating that PMS and Mn-U... 2.5 @MXenes 1.0 There is a stronger synergistic effect between them. The above research results indicate that Mn-U 2.5 @MXenes 1.0 The PMS system exhibits superior ofloxacin removal efficiency and synergistic effects, significantly improving its removal rate.

[0113] Figure 8 For the degradation catalytic material Mn-U 2.5 @Mxenes 1.0Schematic diagram of a cyclic experiment for the degradation of ofloxacin using activated PMS. (Refer to...) Figure 8 The applicant studied Mn-U 2.5 @Mxenes 1.0 The stability and reusability of the catalyst have been tested, demonstrating its potential practicality. In this process, the catalyst material is washed with ethanol and then placed in an oven for simple and convenient recovery. Mn-U 2.5 @Mxenes 1.0 The degradation rate of ofloxacin during the process decreased slightly with increasing reuse (from 95.81% to 73.85%). After four cycles, Mn-U 2.5 @Mxenes 1.0 It still retains certain catalytic degradation performance, indicating that it has strong repeatability as an activator for the removal of ofloxacin by PMS.

[0114] Therefore, in the method of this invention, a catalytic material with abundant oxygen vacancies is first prepared, which can efficiently activate PMS and has a significant synergistic effect with PMS. Mn-U 2.5 @Mxenes 1.0 Combined with PMS, it is used to degrade ofloxacin. Mn-U 2.5 @Mxenes 1.0 The PMS process has advantages such as high efficiency, recyclability, and strong adaptability in degrading ofloxacin.

Claims

1. A method for efficiently activating peroxymonosulfate to degrade ofloxacin, characterized in that, This method uses a degradation catalytic material based on Mxenes carrier, which contains both Mn and N active sites, to activate peroxymonosulfate. By utilizing the synergistic effect of the co-catalysis of Mn and N active sites, the activation effect of peroxymonosulfate is improved, thereby achieving the degradation of ofloxacin in water. This method first prepares an accordion-shaped Mxenes material as a carrier, and introduces it into the interior of the Mxenes material by adding Mn and N precursors; then, Mn-N active sites are loaded by chemical bonding to obtain a two-dimensional layered ofloxacin degradation catalytic material; finally, the prepared ofloxacin degradation catalytic material and peroxymonosulfate are added to the water containing ofloxacin to be degraded, and the ofloxacin degradation catalytic material is used to activate the peroxymonosulfate to achieve the degradation of ofloxacin; The ofloxacin degradation catalytic material is mainly composed of Ti3C2T. x Using Mxenes as the matrix, porous two-dimensional layered structures are formed by loading Mn and N elements to create Mn-O and NO structural configurations, respectively. The chemical formula is Mn-U. 2.5 @MXenes 1.0 ; The ofloxacin degradation catalytic material is prepared according to the following steps: a. Immerse Ti3AlC2 in the corresponding amount of hydrofluoric acid at a ratio of 10 ml per gram, stir and mix evenly at room temperature and react. The suspension obtained by b was repeatedly centrifuged and dehydrated and washed with pure water until the pH of the supernatant was greater than 6. c. The dehydrated precipitate was dried to obtain accordion-shaped Ti3C2T x Mxenes vector; The obtained Mxenes support was pyrolyzed at high temperature, and Mn and N reactive sites were loaded through chemical bonding to generate a two-dimensional layered degradation catalytic material; Step d specifically includes: 1) Adding the two raw materials to 30 mL of DMF according to the ratio of 0.3 g MnCl2•4H2O and mixing and stirring to dissolve; 2) Add 10 mL of ethanol, 5 mL of pure water, and urea in the corresponding proportions, wherein the mass ratio of MnCl2•4H2O to urea is 1:(1.5-3). 3) Add the corresponding proportion of 0.3g MXenes material, stir and mix well; 4) The mixture was kept at 120℃ for 12 h to complete the loading reaction. After cooling to room temperature, it was centrifuged to dehydrate and repeatedly washed and dried to obtain the degradation catalyst material.

2. The method for efficiently activating peroxymonosulfate to degrade ofloxacin as described in claim 1, characterized in that, Stir for 20 hours in step a.

3. The method for efficiently activating peroxymonosulfate to degrade ofloxacin as described in claim 1, characterized in that, In step b, the resulting suspension is centrifuged at 3500 rpm for 5 minutes each time to dehydrate before washing.

4. The method for efficiently activating peroxymonosulfate to degrade ofloxacin as described in claim 1, characterized in that, In step c, dry at 60℃ for 24 hours.

5. The method for efficiently activating peroxymonosulfate to degrade ofloxacin as described in claim 1, characterized in that, During degradation, the prepared ofloxacin degradation catalyst is first added to the water body to be degraded and mixed evenly, and then peroxymonosulfate is added to the water body to be degraded and mixed evenly to complete the degradation reaction. During degradation, the ratio of the ofloxacin degradation catalyst and peroxymonosulfate is as follows: for every 0.01g of ofloxacin in the water, 0.2g of ofloxacin degradation catalyst and 0.5g of peroxymonosulfate are added.

6. The method for efficiently activating peroxymonosulfate to degrade ofloxacin as described in claim 5, characterized in that, After the degradation reaction is completed, the used ofloxacin degradation catalyst material is regenerated. First, the material is washed three times with deionized water. Then, the washed material is soaked in ethanol for 2 hours. Next, it is centrifuged and washed three times with ethanol. Finally, it is washed three times with deionized water and placed in an oven at 60 °C for 12 hours to achieve recycling.

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