A ZnFe-LDH@LCF composite material, a preparation method and application thereof

Abstract

This application discloses a ZnFe-LDH@LCF composite material, its preparation method, and its applications, belonging to the field of functional materials technology. The preparation method includes: preparing lignin-based carbon fibers, surface-activating the lignin-based carbon fibers, and then adding iron ion solution and zinc ion solution for reaction; after the reaction is complete, the reaction solution is sequentially aged and filtered, and the filtered product is dried to obtain the ZnFe-LDH@LCF composite material. The ZnFe-LDH@LCF composite material prepared by the method of this application can not only be recycled and avoid secondary pollution; but also effectively expand the contact area with pollutants, expose more active sites, enhance the interaction between the photocatalytic system and ofloxacin, and thus significantly improve the degradation efficiency.

Description

Technical Field

[0001] This application belongs to the field of functional materials technology, and in particular relates to a ZnFe-LDH@LCF composite material, its preparation method and application. Background Technology

[0002] Wastewater containing ofloxacin has chronic toxicity and easily leads to bacterial resistance. Therefore, research has been conducted on the removal of ofloxacin from wastewater using physical adsorption, photocatalysis, biological and / or chemical degradation techniques. Photocatalysis has been shown to be inexpensive, efficient, and environmentally friendly, and is considered one of the most promising technologies for treating ofloxacin-containing wastewater.

[0003] In related technologies, layered bimetallic hydroxides (LDHs) can be used as photocatalysts to degrade antibiotics in wastewater. Currently, research mainly focuses on using MgAl-LDH, MgFe-LDH, and NiAl-LDH as photocatalysts to degrade tetracycline (TC), diclofenac sodium (DCF), and sulfamethoxazole (SMX) in wastewater, with few reports on the degradation of ofloxacin in wastewater. Furthermore, layered bimetallic hydroxides are mostly in powder form, making them difficult to recycle and prone to causing secondary pollution, greatly limiting their practical application. To address the difficulty of recycling layered bimetallic hydroxides, related technologies further disclose the use of non-woven fabrics as carriers to support them.

[0004] However, non-woven fabrics are generally made of organic polymer materials, which are easily degraded by photocatalysis and cause pollution when used in photocatalysis technology, thus limiting their practical application; in addition, non-woven fabrics have poor conductivity, resulting in a high electron recombination rate and reducing photocatalytic efficiency. Summary of the Invention

[0005] The purpose of this application is to provide a ZnFe-LDH@LCF composite material, its preparation method and application, aiming to solve the technical problems of low photocatalytic efficiency and easy pollution caused by layered bimetallic hydroxide supported on nonwoven fabric photocatalysts.

[0006] To achieve the above objectives, the technical solution of this application is:

[0007] The first aspect of this application provides a method for preparing a ZnFe-LDH@LCF composite material, the method comprising the following steps:

[0008] Preparation of lignin-based carbon fibers;

[0009] After surface activation of the lignin-based carbon fibers, iron ion solution and zinc ion solution are added to carry out the reaction.

[0010] After the reaction is complete, the reaction solution is successively aged and filtered, and the filtered product is dried to obtain the ZnFe-LDH@LCF composite material.

[0011] In a preferred embodiment, the method for preparing lignin-based carbon fibers includes:

[0012] The lignin powder is sequentially melt-blown, pre-oxidized, and carbonized to obtain lignin-based carbon fibers.

[0013] In a more preferred implementation, the meltblowing is performed at a temperature of 240-250°C.

[0014] In a more preferred embodiment, the pre-oxidation is carried out at a temperature of 250-300°C, and the heating rate for the pre-oxidation is 0.15-0.35°C / min, and the time is 60-80min.

[0015] In a more preferred embodiment, the carbonization is carried out at a temperature of 1000-1500°C, and the heating rate for the carbonization is 3-5°C / min, with a time of 60-80min.

[0016] In a preferred embodiment, when adding the iron ion solution and the zinc ion solution for reaction, the addition rate of both the iron ion solution and the zinc ion solution is 0.5-3 mL / min.

[0017] In a more preferred embodiment, the curing is carried out at a temperature of 60-80°C for 20-30 hours.

[0018] In a more preferred embodiment, the drying is carried out at a temperature of 140-150°C for 6-8 hours.

[0019] The second aspect of this application also provides ZnFe-LDH@LCF composite materials prepared by the method described in the first aspect.

[0020] The third aspect of this application also provides the application of the ZnFe-LDH@LCF composite material described in the second aspect in the degradation treatment of ofloxacin.

[0021] Compared with the prior art, the advantages or beneficial effects of this application include at least the following:

[0022] The preparation method provided in the first aspect of this application enables the in-situ generation of regular and uniform layered bimetallic hydroxide (ZnFe-LDH) on the surface of lignin-based carbon fibers, thereby achieving effective loading of layered bimetallic hydroxide on the surface of lignin-based carbon fibers. Firstly, this application discloses for the first time the loading of ZnFe-LDH onto the surface of lignin-based carbon fibers. This allows the utilization of the excellent chemical stability and resistance to photocatalytic degradation of lignin-based carbon fibers, making the photocatalyst ZnFe-LDH easy to recycle and effectively avoiding secondary pollution. Furthermore, the large specific surface area and controllable porosity of lignin-based carbon fibers effectively expand the contact area with pollutants, expose more active sites, enhance the interaction between the photocatalytic system and ofloxacin, and significantly improve degradation efficiency. Secondly, the raw materials used in the preparation of the ZnFe-LDH@LCF composite material in this application are readily available, low-cost, and environmentally friendly, which is conducive to promoting industrial production.

[0023] The ZnFe-LDH@LCF composite material provided in the second aspect of this application, by loading layered bimetallic hydroxide (ZnFe-LDH) onto the surface of lignin-based carbon fiber (LCF), enables the layered bimetallic hydroxide and lignin-based carbon fiber to fully exert a synergistic effect, thereby giving the ZnFe-LDH@LCF composite material a more efficient degradation efficiency while facilitating the recycling of layered bimetallic hydroxide.

[0024] The ZnFe-LDH@LCF composite material provided in the third aspect of this application, when used in the treatment of oxyfloxacin-containing wastewater, exhibits advantages such as high photocatalytic degradation efficiency and easy recyclability. Therefore, after use in the treatment of oxyfloxacin-containing wastewater, the ZnFe-LDH@LCF composite material not only effectively degrades and removes oxyfloxacin from the wastewater, but also, as a photocatalyst, the ZnFe-LDH@LCF composite material can be recycled, resulting in low treatment costs, no pollution, and facilitating industrial application. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The XRD pattern of ZnFe-LDH@LCF-1 provided in the embodiments of this application;

[0027] Figure 2SEM images of ZnFe-LDH@LCF-1 provided in the embodiments of this application;

[0028] Figure 3 AFM diagram of ZnFe-LDH@LCF-1 provided in the embodiments of this application;

[0029] Figure 4 XPS spectra of ZnFe-LDH@LCF-1, LCF-1, and ZnFe-LDH provided for embodiments of this application;

[0030] Figure 5 UV-Vis image of ZnFe-LDH@LCF-1 degradation of ofloxacin provided in the embodiments of this application;

[0031] Figure 6 The efficiency diagram of ZnFe-LDH@LCF-1 cyclic degradation of ofloxacin provided in the embodiments of this application. Detailed Implementation

[0032] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0033] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0034] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0035] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0036] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0037] It should be noted that all raw materials and / or reagents in the embodiments of this application were purchased commercially or prepared according to conventional methods well known to those skilled in the art. Furthermore, the terms "curing," "activation," "meltblowing," "pre-oxidation," and "carbonization," etc., used in the following descriptions of the embodiments of this application are specifically understood according to their general meaning in the art. For example, "curing" refers to placing lignin-based carbon fibers with a surface-loaded layered bimetallic hydroxide precursor into a curing chamber to allow the layered bimetallic hydroxide precursor to crosslink, solidify, and evaporate the solvent; "activation" refers to immersing lignin-based carbon fibers in an activation solution to introduce activating groups such as hydroxyl groups onto the surface of the lignin-based carbon fibers.

[0038] Before providing a detailed explanation of the embodiments of this application, the technical principles of the embodiments of this application will be explained first.

[0039] This application demonstrates a highly efficient degradation of ofloxacin in wastewater through the synergistic effect of layered bimetallic hydroxide (ZnFe-LDH) and lignin-based carbon fiber (LCF). Under visible light irradiation, electrons in the valence band of ZnFe-LDH are rapidly induced to the conduction band, simultaneously generating holes. Due to the excellent conductivity of lignin-based carbon fiber, the photogenerated electrons are rapidly conducted away, reducing the electron-hole recombination rate and thus improving photocatalytic efficiency. Subsequently, the photogenerated electrons reduce O2 in the wastewater to highly reactive superoxide radical anions (·O2). - ) and hydroxyl radicals (·OH), superoxide radical anions (·O2) - ) and hydroxyl radicals (·OH) can attack and destroy ofloxacin molecules. Ofloxacin can be directly oxidized by photogenerated holes, or holes can react with water molecules to produce hydroxyl radicals (·OH), which then attack ofloxacin molecules, ultimately successfully degrading ofloxacin in water.

[0040] In a first aspect, embodiments of this application provide a method for preparing a ZnFe-LDH@LCF composite material. The method includes the following steps:

[0041] Preparation of lignin-based carbon fibers;

[0042] After surface activation of the lignin-based carbon fibers, iron ion solution and zinc ion solution are added to carry out the reaction.

[0043] After the reaction is complete, the reaction solution is successively aged and filtered, and the filtered product is dried to obtain the ZnFe-LDH@LCF composite material.

[0044] It should be noted that the surface activation of lignin-based carbon fibers involves immersing the lignin-based carbon fibers in an activation solution to introduce activating groups onto the surface of the lignin-based carbon fibers. In this embodiment, it is preferable to immerse the lignin-based carbon fibers in a mixed solution of sodium carbonate and sodium hydroxide to introduce hydroxyl (-OH) functional groups onto the surface of the lignin-based carbon fibers. This allows the lignin-based carbon fibers to bond with metal ions such as zinc ions through O-Zn bonds, thus providing binding sites through surface activation.

[0045] In this embodiment, ZnFe-LDH@LCF composite material is prepared by surface activation of lignin-based carbon fibers, followed by reaction, aging, and filtration with iron and zinc ion solutions, and then drying the filtered product. Firstly, the excellent chemical stability and resistance to photocatalytic degradation of lignin-based carbon fibers make the ZnFe-LDH photocatalyst easy to recycle, effectively avoiding secondary pollution. Secondly, the large specific surface area and controllable porosity of lignin-based carbon fibers effectively expand the contact area with pollutants, exposing more active sites and enhancing the interaction between the photocatalytic system and ofloxacin, thus significantly improving degradation efficiency. Thirdly, the raw materials used in this preparation are readily available, low-cost, and environmentally friendly, which is conducive to promoting industrial production.

[0046] In this embodiment of the application, the method for preparing lignin-based carbon fibers preferably includes: sequentially performing melt-blowing, pre-oxidation, and carbonization on lignin powder to obtain lignin-based carbon fibers. Melt-blowing refers to the process of using high-speed hot air to draw a fine stream of lignin melt to form ultrafine fibers.

[0047] It should be noted that, in this embodiment of the application, the lignin powder is melt-blown before pre-oxidation and carbonization, which can effectively control the microstructure of lignin-based carbon fibers and make them form a regular morphology of cylindrical interlaced arrangement. This is beneficial to the loading of layered bimetallic hydroxides, thereby enhancing the synergistic effect between lignin-based carbon fibers and layered bimetallic hydroxides.

[0048] In a specific embodiment, the melt-blowing is preferably performed at a temperature of 240-250°C. Melt-blowing at this temperature enables the preparation of lignin fibers with a narrow diameter distribution and low roughness.

[0049] In a specific embodiment, the pre-oxidation is preferably carried out at a temperature of 250-300°C, and the heating rate for the pre-oxidation is preferably 0.15-0.35°C / min, with a time of 60-80 min. Under these conditions, pre-oxidation enables the fibers to undergo cyclization, cross-linking, and oxidation reactions, significantly improving the thermal stability of the fibers and preventing fiber fusion during carbonization.

[0050] In a specific embodiment, the carbonization is preferably carried out at a temperature of 1000-1500°C, and the heating rate for carbonization is preferably 3-5°C / min, with a preferred time of 60-80min. Carbonization under these conditions can produce lignin-based carbon fibers with smooth surfaces, high integrity, and good electrical conductivity.

[0051] In a specific embodiment, when the iron ion solution and zinc ion solution are added for reaction, the addition rate of both the iron ion solution and the zinc ion solution is preferably 0.5-3 mL / min. Controlling the addition rate of the iron ion solution and zinc ion solution to 0.5-3 mL / min effectively controls the reaction rate of iron / zinc ions on the surface of lignin-based carbon fibers, thereby controlling the morphology and structure of the layered bimetallic hydroxide, resulting in a regular layered structure.

[0052] In a specific embodiment, the curing is preferably carried out at a temperature of 60-80°C, and the curing time is preferably 20-30 hours. Curing under these conditions allows the layered bimetallic hydroxide in the solute to crystallize or deposit onto the lignin-based carbon fibers.

[0053] In a specific embodiment, the drying is preferably carried out at a temperature of 140-150°C, and the drying time is preferably 6-8 hours. Drying under these conditions ensures that the obtained layered bimetallic hydroxide is uniformly distributed on the lignin-based carbon fibers.

[0054] Secondly, embodiments of this application also provide a ZnFe-LDH@LCF composite material prepared by the method described in the first aspect. The ZnFe-LDH@LCF composite material enables a synergistic effect between ZnFe-LDH (layered bimetallic hydroxide) and LCF (lignin-based carbon fiber), thereby giving the ZnFe-LDH@LCF composite material a more efficient degradation rate.

[0055] Thirdly, embodiments of this application also provide the application of the ZnFe-LDH@LCF composite material described in the second aspect in the degradation of ofloxacin. This is because the ZnFe-LDH@LCF composite material possesses high photocatalytic degradation efficiency and is easy to recycle. Therefore, after being used to treat ofloxacin-containing wastewater, the ZnFe-LDH@LCF composite material can not only effectively degrade ofloxacin in the wastewater, but also, as a photocatalyst, the ZnFe-LDH@LCF composite material can be easily recycled, resulting in low treatment costs, no pollution, and facilitating industrial application.

[0056] The technical solution of this application will be further described below with reference to specific embodiments.

[0057] Example 1

[0058] This embodiment provides a method for preparing composite material M1 (ZnFe-LDH@LCF-1), including the following steps S101-S107:

[0059] S101: Lignin powder is melt-blown at a temperature of 240℃ to obtain lignin nonwoven fabric;

[0060] S102: The lignin nonwoven fabric is pre-oxidized and kept at 280°C for 1 hour, wherein the heating rate is 0.25°C / min, to obtain a lignin-based carbon fiber precursor.

[0061] S103: The lignin-based carbon fiber precursor is carbonized at 1000℃ for 1 hour, wherein the heating rate is 5℃ / min, to obtain lignin-based carbon fiber (LCF-1).

[0062] S104: Add 1.06g of sodium carbonate and 0.16g of sodium hydroxide to 30mL of deionized water, stir for 20min, mix well, and obtain an activated solution;

[0063] S105: Immerse 0.25g of the lignin-based carbon fiber (LCF-1) into the activation solution, and simultaneously add 0.01g / mL of ferric sulfate hydrate solution and 0.004g / mL of zinc sulfate hydrate solution at a rate of 2mL / min, and then stir the reaction for 30min.

[0064] S106: The mixed solution after the reaction is aged at 80°C for 24 hours;

[0065] S107: Filter the matured solution, collect the filtered product and dry it at 150℃ for 6 hours to obtain composite material M1 (ZnFe-LDH@LCF-1).

[0066] Example 2

[0067] This embodiment provides a method for preparing composite material M2 (ZnFe-LDH@LCF-2), including the following steps S201-S207:

[0068] S201: Lignin powder is melt-blown at a temperature of 240℃ to obtain lignin nonwoven fabric;

[0069] S202: The lignin nonwoven fabric is pre-oxidized and kept at 280°C for 1 hour, wherein the heating rate is 0.25°C / min, to obtain a lignin-based carbon fiber precursor.

[0070] S203: The lignin-based carbon fiber precursor is carbonized at 1000℃ for 1 hour, wherein the heating rate is 5℃ / min, to obtain lignin-based carbon fiber (LCF-2).

[0071] S204: Add 1.06g of sodium carbonate and 0.16g of sodium hydroxide to 30mL of deionized water, stir for 20min, mix well, and obtain an activated solution;

[0072] S205: Immerse 0.25g of the lignin-based carbon fiber (LCF-2) into the activation solution, and simultaneously add 0.01g / mL of ferric sulfate hydrate solution and 0.008g / mL of zinc sulfate hydrate solution at a rate of 2mL / min, and then stir the reaction for 30min.

[0073] S206: The mixed solution after the reaction is aged at 80°C for 24 hours;

[0074] S207: Filter the matured solution, collect the filtered product and dry it at 150℃ for 6 hours to obtain composite material M2 (ZnFe-LDH@LCF-2).

[0075] Example 3

[0076] This embodiment provides a method for preparing composite material M3 (ZnFe-LDH@LCF-3), including the following steps S301-S307:

[0077] S301: Lignin powder is melt-blown at a temperature of 240℃ to obtain lignin nonwoven fabric;

[0078] S302: The lignin nonwoven fabric is pre-oxidized and kept at 280°C for 1 hour, wherein the heating rate is 0.25°C / min, to obtain a lignin-based carbon fiber precursor.

[0079] S303: The lignin-based carbon fiber precursor is carbonized at 1000℃ for 1 hour, wherein the heating rate is 5℃ / min, to obtain lignin-based carbon fiber (LCF-3).

[0080] S304: Add 1.06g of sodium carbonate and 0.16g of sodium hydroxide to 30mL of deionized water, stir for 20min, mix well, and obtain an activated solution;

[0081] S305: Immerse 0.25g of the lignin-based carbon fiber (LCF-3) into the activation solution, and simultaneously add 0.01g / mL of ferric sulfate hydrate solution and 0.002g / mL of zinc sulfate hydrate solution at a rate of 2mL / min, and then stir the reaction for 30min.

[0082] S306: The mixed solution after the reaction is aged at 80°C for 24 hours;

[0083] S307: After aging, the solution is filtered, the filtered product is collected and dried at 150℃ for 6 hours to obtain composite material M3 (ZnFe-LDH@LCF-3).

[0084] To verify and illustrate the actual technical effects of this application, Comparative Example 1 is also provided in the embodiments of this application.

[0085] Comparative Example 1

[0086] This comparative example provides a method for preparing a layered bimetallic hydroxide (ZnFe-LDH), specifically including the following steps S401-S404:

[0087] S401: Add 1.06g of sodium carbonate and 0.16g of sodium hydroxide to 30mL of deionized water, stir for 20min, mix well, and obtain an activated solution;

[0088] S402: Add 0.01 g / mL ferric sulfate hydrate solution and 0.004 g / mL zinc sulfate hydrate solution dropwise to the activation solution at a rate of 2 mL / min, and stir the reaction for 30 min;

[0089] S403: The mixed solution after the reaction is aged at 80°C for 24 hours;

[0090] S404: After aging, the solution is filtered, the filtered product is collected and dried at 150°C for 6 hours to obtain layered bimetallic hydroxide (ZnFe-LDH).

[0091] The LCF-1 and ZnFe-LDH@LCF-1 of Example 1 and the layered bimetallic hydroxide ZnFe-LDH of Comparative Example 1 were characterized in structure and tested in performance, as follows:

[0092] 1.1 XRD Characterization

[0093] XRD characterization of ZnFe-LDH@LCF-1 yielded the following results: Figure 1 As shown. Among them, Figure 1 The XRD pattern of ZnFe-LDH@LCF-1 is shown.

[0094] according to Figure 1 It can be seen that the diffraction peak at 2θ value of 10.8° belongs to the (003) crystal plane of LDH, which characterizes the layered structure of LDH; the diffraction peak at 23.8° is the (002) crystal plane, which corresponds to the reflection caused by stacked graphite-like sheets, indicating that the lignin-based carbon fiber (LCF-1) prepared in Example 1 has a graphite-like structure.

[0095] 1.2 SEM characterization

[0096] Electron microscopy was performed on ZnFe-LDH@LCF-1, and the results were as follows: Figure 2 As shown. Among them, Figure 2 The SEM image of ZnFe-LDH@LCF-1 is shown.

[0097] according to Figure 2 It can be seen that the lignin-based carbon fiber (LCF-1) is arranged in a cylindrical interlaced pattern, and ZnFe-LDH is uniformly and regularly loaded on the surface of the lignin-based carbon fiber (LCF-1).

[0098] 1.3 AFM Characterization

[0099] Atomic force microscopy was performed on ZnFe-LDH@LCF-1, and the results were as follows: Figure 3 As shown. Among them, Figure 3 The AFM plot of ZnFe-LDH@LCF-1 is shown.

[0100] according to Figure 3 As can be seen, the ZnFe-LDH prepared in the embodiments of this application has a layered structure with a layer thickness between 10-15 nm.

[0101] 1.4 XPS characterization

[0102] XPS characterization was performed on LCF-1 and ZnFe-LDH@LCF-1 prepared in Example 1 and ZnFe-LDH prepared in Comparative Example 1. The results are as follows: Figure 4 As shown. Among them, Figure 4XPS spectra of ZnFe-LDH@LCF-1, LCF-1, and ZnFe-LDH are shown.

[0103] according to Figure 4 It can be seen that lignin-based carbon fibers (LCF-1) and layered bimetallic hydroxides (ZnFe-LDH) are bonded through MOM (where M is ZnFe). 2+ Fe 3+ They are tightly connected in a way that allows them to communicate effectively.

[0104] 1.5 Photocatalytic performance test

[0105] To verify the photocatalytic performance of the composite material M1 (ZnFe-LDH@LCF-1) prepared in Example 1, this application conducted photocatalytic performance tests on ZnFe-LDH@LCF-1, specifically including:

[0106] S501: Prepare 40 mL of ofloxacin aqueous solution with a concentration of 10 mg / L;

[0107] S502: 0.2g of ZnFe-LDH@LCF-1 was placed into the ofloxacin aqueous solution and magnetically stirred for 1h under no light conditions. After reaching the adsorption / desorption equilibrium, 3mL of ofloxacin aqueous solution was filtered through a 0.45μm PTFE syringe, and ofloxacin in the ofloxacin aqueous solution was quantitatively detected by ultraviolet spectrophotometer. The detected value was recorded as C0.

[0108] S503: Maintain the magnetic stirring of step S502, place a 500W xenon lamp light source 10cm above the reaction vessel and turn it on. After reacting for 2 hours, filter the ofloxacin aqueous solution through a 0.45μm PTFE syringe, use an ultraviolet spectrophotometer to quantitatively detect ofloxacin in the ofloxacin aqueous solution, and calculate the degradation efficiency using formula (1).

[0109] η=(C0-C) / C0 (1)

[0110] In formula (1), η is the photocatalytic degradation efficiency, C0 is the initial concentration before light irradiation, and C is the concentration of ofloxacin after photocatalytic treatment;

[0111] S504: Take out ZnFe-LDH@LCF-1 from the ofloxacin aqueous solution and test its reusability through the same process as steps S501, S502, and S503, and cycle it 5 times.

[0112] The test results are Figures 5 to 6 As shown. Among them, Figure 5 The UV-Vis image of ZnFe-LDH@LCF-1 degradation of ofloxacin is shown. Figure 6The efficiency diagram of ZnFe-LDH@LCF-1 in the cyclic degradation of ofloxacin is shown.

[0113] according to Figure 5 It is known that the maximum absorption wavelength of ofloxacin is 290 nm. After the photocatalytic reaction, the absorption peak drops significantly. Repeated experiments show that the average degradation efficiency exceeds 95%.

[0114] according to Figure 6 It can be seen that the degradation efficiency of ofloxacin (OFX) was above 95% in all five cycles without significant decrease, indicating that the ZnFe-LDH@LCF prepared in this application has good reusability.

[0115] In summary, this application prepares a ZnFe-LDH@LCF composite material by surface activation of lignin-based carbon fibers, followed by reaction, aging, and filtration with iron and zinc ion solutions, and drying the filtered product. Firstly, the excellent chemical stability and resistance to photocatalytic degradation of lignin-based carbon fibers make the ZnFe-LDH photocatalyst easy to recycle, effectively avoiding secondary pollution. Secondly, the large specific surface area and controllable porosity of lignin-based carbon fibers effectively expand the contact area with pollutants, exposing more active sites and enhancing the interaction between the photocatalytic system and ofloxacin, resulting in a significant improvement in degradation efficiency. Thirdly, the raw materials used in this preparation are readily available, low-cost, and environmentally friendly, which is conducive to promoting industrial production.

[0116] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0117] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. Application of a ZnFe-LDH@LCF composite material in the degradation treatment of ofloxacin, characterized in that, The preparation method of the ZnFe-LDH@LCF composite material comprises the following steps: Preparation of lignin-based carbon fiber; After 0.25 g of the lignin-based carbon fiber is immersed in a mixed solution of sodium carbonate and sodium hydroxide for surface activation, 0.01 g / mL of an iron ion solution and 0.04 g / mL of a zinc ion solution are added for reaction, wherein the adding speed of the iron ion solution and the zinc ion solution is 0.5-3 mL / min. After the reaction is completed, the reaction solution is sequentially matured and filtered, and the filtered product is dried, to obtain the ZnFe-LDH@LCF composite material, wherein the lignin-based carbon fiber is in a cylindrical staggered arrangement, the ZnFe-LDH is uniformly and regularly loaded on the surface of the lignin-based carbon fiber, and the lignin-based carbon fiber and the ZnFe-LDH are tightly connected in a M-O-M mode, M being Zn 2+ , Fe 3 + ; The method for preparing the lignin-based carbon fiber comprises the following steps: sequentially performing melt blowing, pre-oxidation and carbonization on lignin powder, and thus the lignin-based carbon fiber is obtained; wherein the melt blowing is performed at a temperature of 240-250 DEG C.

2. Use according to claim 1, characterized in that, The pre-oxidation is performed at a temperature of 250-300 DEG C. The temperature increasing rate for the pre-oxidation is 0.15-0.35 DEG C / min, and the time is 60-80 min.

3. Use according to claim 1, characterized in that, The carbonization is performed at a temperature of 1000-1500 DEG C. The temperature increasing rate for the carbonization is 3-5 DEG C / min, and the time is 60-80 min.

4. Use according to claim 1, characterized in that, at 60-80 o The ripening is carried out at a temperature of 20-30°C for a time of 20-30 h.

5. The use according to claim 1, characterized in that, at 140-150 o The drying is carried out at a temperature of 140-150°C for a time of 6-8 h.

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