Nano-mofs loaded bio-based fiber photo-fenton catalytic material, preparation method and application thereof

Abstract

The application provides a kind of nanometer MOFs load biological fiber photo-Fenton catalytic material and its preparation method and application, the present application with green and environment-friendly photosensitive material 4-carboxyl phenyl porphyrin TCPP as organic ligand, Fe 2+ Nano Fe-MOFs is prepared for central metal, and is loaded to biological cotton fiber surface for photo-Fenton degradation of organic pollutants. The combination of nano Fe-MOFs and biological cotton fiber is mainly enhanced, which includes plasma cleaning, alkalization treatment and carboxymethyl treatment of the fiber. Compared with traditional powder catalytic materials, the three-dimensional composite material Fe-MOFs / CF is convenient to recycle after use, which greatly improves the practical performance of the material. The present application has the advantages of green, environmental protection, fast degradation rate, high removal rate, easy recovery and the like.

Description

Technical Field

[0001] This invention belongs to the fields of bio-based environmental protection materials and nano-metal-organic framework materials, involving multiple technical areas such as the combination of nanomaterials and bio-based carriers, photocatalysis, Fenton-like degradation and organic matter removal. Specifically, it relates to a bio-based fiber photo-Fenton catalytic material supported on nano-MOFs, its preparation method, and its application. Background Technology

[0002] With the development of persistent organic pollutant (POP) degradation in wastewater, antibiotics have been identified as emerging pollutants. Their persistent impact on the entire ecosystem directly leads to irreversible damage worldwide. Currently, methods for removing antibiotics and other organic pollutants mainly include ion exchange, microbial treatment, membrane filtration, adsorption, and Fenton advanced oxidation degradation. Among these, Fenton-like advanced oxidation methods are considered one of the most promising organic pollutant removal technologies due to their strong oxidative degradation capabilities, lack of pollution, environmental friendliness, and simple operation. Fenton-like reactions are advanced oxidation processes that utilize transition metals (such as iron, copper, and manganese) or their compounds to catalyze the generation of highly reactive free radicals (such as ·OH) from hydrogen peroxide, which are then used to degrade organic pollutants. Common Fenton-like catalysts include iron oxides, copper oxides, single-atom catalysts, and metal-organic frameworks (MOFs). Among various Fenton-like catalysts, MOFs, due to their active metal centers, large specific surface areas, and abundant pore structures, have shown great potential in the field of catalytic degradation. However, there are some drawbacks in Fenton-like reactions. For example, powdered Fenton-like catalysts are difficult to recover, and the slow cycling of metal valence states in Fenton-like catalysts leads to insufficient free radical yields. To improve free radical conversion efficiency, some studies have used photo-Fenton technology to enhance degradation efficiency. Photo-Fenton technology, based on Fenton-like processes, introduces ultraviolet or visible light to significantly increase the generation efficiency of free radicals, thereby enhancing the degradation capacity of organic pollutants. The photo-Fenton catalyst plays a crucial role in the reaction process; it must be able to activate hydrogen peroxide and also be photoexcited to generate photo-generated electrons to promote metal valence state cycling. Therefore, it is essential to explore photo-Fenton catalysts that are environmentally friendly, highly efficient, and easily recoverable. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a nano-MOFs-supported bio-based fiber photo-Fenton catalytic material, its preparation method, and its application. To enhance the bonding ability between the nano-MOFs and bio-based cotton fibers, the cotton fiber (CF) underwent a series of pretreatments, including plasma cleaning, alkalization, and carboxymethylation. Using the photosensitive material 4-carboxyphenylporphyrin TCPP as the organic ligand and Fe as the central metal, the nano-MOFs were successfully prepared by in-situ growth onto the surface of the cotton fiber (CF) via a hydrothermal method. 0.2-MOFs / CF composites. 4-Carboxyphenylporphyrin TCPP, as a green organic ligand, possesses good visible light harvesting ability, especially its ability to implant single atoms into the center of a rigid framework. Therefore, 4-carboxyphenylporphyrin TCPP is mainly used as a component of various photosensitive MOFs. Photoinduced ee by 4-carboxyphenylporphyrin TCPP excitation... − It can transfer to Fe3O(COO)6, leading to the accelerated reduction of Fe(III) to Fe(II), further promoting the generation of free radicals. Using the photosensitizer 4-carboxyphenylporphyrin TCPP as an organic ligand and the Fenton-active Fe ion as the central metal, Fe-MOFs were synthesized hydrothermally and loaded onto cotton fibers to improve their dispersibility and practicality. Simultaneously, this combination promoted the separation of photogenerated electron-hole pairs, improved the redox capacity of Fe(II) / Fe(III) in the MOFs, and the synergistic effect of photocatalysis and Fenton significantly improved the degradation efficiency.

[0004] Under light irradiation, the catalyst activates H2O2 to generate free radicals. These free radicals attack tetracycline TC and other organic pollutants and decompose them into small molecules CO2 and H2O. The degradation system of this invention has the advantages of being green, environmentally friendly, fast in degradation rate, high in removal rate, strong in anti-interference ability, and easy to recycle. It has been successfully used for the degradation of tetracycline TC and other organic pollutants.

[0005] The present invention achieves the above-mentioned technical objectives through the following technical means.

[0006] A method for preparing a nano-MOFs-supported bio-based fiber photoFenton catalytic material, characterized by comprising the following steps:

[0007] Step S1, Pretreatment of bio-based cotton fiber (CF):

[0008] The cleaned cotton fiber CF was plasma cleaned for 60 seconds, followed by alkalization to activate the cellulose in the cotton fiber CF, and finally carboxymethylation of the cotton fiber CF. This series of measures is beneficial for loading metal-organic frameworks (MOFs).

[0009] Step S2, Fe nano-MOFs bio-based fiber composite material X Preparation of MOFs / CF:

[0010] FeCl₂ • 6H₂O was dissolved in an organic solvent, and then the pretreated cotton fibers CF from step S1 were impregnated in the organic solvent for 8 h; subsequently, benzoic acid and 4-carboxyphenylporphyrin TCPP were dissolved in the solvent, with the ratio of benzoic acid:4-carboxyphenylporphyrin TCPP:FeCl₂ • 6H₂O = 30:1:5; the mixture was then subjected to a hydrothermal reaction at 90 °C for 5 h to obtain Fe X -MOFs / CF; then the prepared Fe X - The MOFs / CF were first dried and then washed with ethanol to remove undissolved ligands, yielding the final nano-MOFs bio-based fiber composite material Fe. X -MOFs / CF; Fe X In MOFs / CF, X represents the amount of FeCl2 • 6H2O doping.

[0011] In this step, the ratio of benzoic acid: 4-carboxyphenylporphyrin TCPP: FeCl2 • 6H2O = 30:1:5 is kept constant, and the volume of the organic solvent is not changed. The loading rate of MOFs on cotton fiber CF is changed by changing the amount of FeCl2 • 6H2O.

[0012] Preferably, the alkalization treatment in step S1 is to swell the cotton fiber CF and activate the cellulose to facilitate better carboxymethylation. The alkali is a 20%~30% mass ratio NaOH solution, and 50 ml of NaOH solution corresponds to 0.5 g~1.0 g of cotton fiber CF. Stirring is carried out at room temperature (25~30℃) for 1~3 h.

[0013] In the above scheme, carboxymethylation in step S1 is to improve the binding of MOFs to cotton fiber CF. 50 ml of a 20%–30% chloroacetic acid solution corresponds to 0.5 g–1.0 g of cotton fiber CF, and the reaction is carried out at 50°C–70°C for 2–4 h.

[0014] Preferably, the organic solvent in step S2 is either N,N-dimethylformamide or ethanol.

[0015] Preferably, in step S3, X is 0.05~0.25. In step S3, the ratio of benzoic acid:4-carboxyphenylporphyrin TCPP:FeCl2 • 6H2O is kept constant at 30:1:5, and the volume of the organic solvent is kept constant. The loading rate of MOFs is changed by altering the amount of FeCl2 • 6H2O. XThe amounts of benzoic acid, 4-carboxyphenylporphyrin TCPP, and FeCl2 •6H2O in MOFs / CF were 0.3 g, 0.01 g, 0.05 g; 0.6 g, 0.02 g, 0.10 g; 0.9 g, 0.03 g, 0.15 g; 1.2 g, 0.04 g, 0.20 g; and 1.5 g, 0.05 g, 0.25 g, respectively; while the amount of pretreated cotton fiber CF was fixed at 0.5 g.

[0016] Preferably, step S3 Fe X The optimal X content in MOFs / CF is 0.2, namely benzoic acid, 4-carboxyphenylporphyrin TCPP, and FeCl2 • 6H2O, with concentrations of 1.2 g, 0.04 g, and 0.20 g respectively. The nano-MOFs bio-based fiber composite material is Fe... 0.2 -MOFs / CF.

[0017] A MOFs-based bio-based fiber composite material Fe was prepared according to the preparation method of the aforementioned nano-MOFs-supported bio-based fiber photo-Fenton catalytic material. 0.2 - Application of MOFs / CFs in the degradation and removal of tetracycline (TC) and other organic pollutants. These other organic pollutants include methyl orange (MO), methylene blue (MB), norfloxacin (NFX), enrofloxacin (ENR), and oxytetracycline (OTC).

[0018] In the above scheme, the Fe nano-MOFs bio-based fiber composite material is used. 0.2 The application of MOFs / CF in catalyzing the generation of free radicals from hydrogen peroxide (H₂O₂) under light irradiation to oxidize and degrade tetracycline (TC) and other organic pollutants includes the following steps:

[0019] Weigh out Fe from the nano-MOFs bio-based fiber composite material 0.2 MOFs / CF are added to the water to be treated, which contains tetracycline (TC) and other organic pollutants. Hydrogen peroxide (H₂O₂) is added under xenon lamp irradiation to adjust the pH. The solution is then transferred through a nano-MOFs bio-based fiber composite material (Fe). 0.2 -MOFs / CF catalyze H2O2 to generate free radicals to degrade and remove TC and other organic pollutants.

[0020] Furthermore, the nano-MOFs bio-based fiber composite material Fe 0.2 The MOFs / CF dosage was 0.05 g·L⁻¹. –1 ~0.25 g·L –1 The amount of hydrogen peroxide (H₂O₂) used is 5 mM to 40 mM, and the pH is adjusted to 2 to 10; the amount of organic pollutants is 10 mg·L⁻¹. –1 ~100 mg·L –1Xenon lamp illumination intensity: 100 mW / cm².

[0021] Furthermore, the nano-MOFs bio-based fiber composite material Fe 0.2 The MOFs / CF dosage was 0.20 g·L⁻¹. –1 .

[0022] Furthermore, the amount of hydrogen peroxide (H2O2) used is 30 mM.

[0023] Furthermore, the pH is 6.

[0024] Furthermore, the organic pollutant 50 mg·L –1 .

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] (1) This invention uses 4-carboxyphenylporphyrin TCPP as an organic ligand and ferrous ion as the central metal to prepare a novel nano MOFs and load them onto bio-based fibers for photo-Fenton efficient degradation of organic pollutants.

[0027] (2) This invention provides a bio-based fiber surface treatment method to enhance the loading effect of nano-MOFs, namely plasma cleaning, alkalization treatment, and carboxymethylation treatment. The three processes can greatly enhance the bonding ability between nano-MOFs and fibers, and improve the usability and recyclability of the material.

[0028] (3) Fe prepared in this invention 0.2 -MOFs / CF catalyzes the degradation and removal of tetracycline TC and other organic pollutants under light conditions. It has good stability and high removal efficiency, especially for tetracycline TC, which can achieve a removal rate of 99.13% after 60 min of degradation. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the preparation process;

[0030] Figure 2 A schematic diagram illustrating the mechanism of photo-Fenton degradation of TC;

[0031] Figure 3 This is a scanning electron microscope image of the material. Figure 3 Image (a) is a scanning electron microscope (SEM) image of fresh cotton fibers (CF). Figure 3 (b) is an electron micrograph of cotton fibers after alkali treatment and carboxymethylation. Figure 3 (c) represents Fe 0.2 - Electron micrograph of MOFs / CF composite material Figure 3 (d) represents Fe 0.2- A magnified view of a portion of the MOFs / CF composite material;

[0032] Figure 4 For the characterization spectrum of the material, Figure 4 In the middle (a), Fe is... 0.2 -MOFs, CF, Fe 0.2 XRD patterns of MOFs / CF Figure 4 (b) represents Fe 0.2 -MOFs, Fe 0.2 XPS plots of MOFs / CF;

[0033] Figure 5 Composite materials with different Fe doping ratios (Fe X Removal rate of tetracycline TC by MOFs / CF;

[0034] Figure 6 To investigate the effects of different conditions on the removal rate of tetracycline (TC), Figure 6 In Figure (a), the effect of different pH values ​​on the removal rate of tetracycline (TC) is shown. Figure 6 (b) shows the effect of different catalyst dosages on the removal rate of tetracycline (TC). Figure 6 (c) shows the effect of different hydrogen peroxide (H2O2) on the removal rate of tetracycline (TC). Figure 6 (d) shows the removal effect of the system on different concentrations of tetracycline (TC);

[0035] Figure 7 The ability to degrade and remove tetracycline (TC) in different systems. Figure 7 (a) shows the change of TC in the degradation of tetracycline over time in different systems. Figure 7 (b) shows the removal rate of tetracycline TC in different systems after 60 min of degradation;

[0036] Figure 8 The graph shows the changes over time in the degradation of different organic pollutants by the photo-Fenton system. Detailed Implementation

[0037] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0038] Example 1: A method for preparing a bio-based fiber photoFenton catalytic material supported on nano-MOFs, comprising the following steps:

[0039] MOFs bio-based fiber composites Fe 0.2 Preparation steps of MOFs / CF:

[0040] Step S1, Cotton fiber CF pretreatment:

[0041] Cotton fiber CF was cleaned alternately with deionized water and ethanol, and after drying, it was plasma-cleaned for 60 seconds to activate the oxygen-containing functional groups on the cotton fiber surface. Subsequently, an alkalization treatment was performed to activate the cellulose in the cotton fiber CF. 0.5 g of cotton fiber CF was immersed in 50 ml of a 20% (w / w) NaOH solution and stirred at 25°C for 2 hours. Finally, the cotton fiber CF was carboxymethylated by immersing 0.5 g of cotton fiber CF in 50 ml of a 20% chloroacetic acid solution and reacting at 70°C for 2 hours. Figure 3 As shown in (a), the surface of fresh cotton fiber (CF) is very smooth. After plasma treatment, alkali treatment, and carboxymethylation treatment, the surface of cotton fiber (CF) exhibits a helical microfiber structure. This structure can effectively load nano-MOFs, and its structure is as follows: Figure 3 As shown in (b).

[0042] Step S2, Fe nano-MOFs bio-based fiber composite material X Preparation of MOFs / CF:

[0043] Fe X The preparation of -MOFs / CF involves dissolving 0.05 g–0.25 g of FeCl₂ • 6H₂O in 40 ml of ethanol solution, followed by impregnation of pretreated cotton fiber CF in the solution for 8 h. Subsequently, 0.3 g–1.5 g of benzoic acid and 0.01 g–0.05 g of 4-carboxyphenylporphyrin TCPP are dissolved in the solution, with a benzoic acid:4-carboxyphenylporphyrin TCPP:FeCl₂ • 6H₂O ratio of 30:1:5. The mixture is then subjected to a hydrothermal reaction at 90 °C for 5 h to obtain Fe... X -MOFs / CF. Then the prepared Fe... X -MOFs / CF were first dried and then washed to obtain the final nano-MOFs bio-based fiber composite material Fe. X -MOFs / CF.

[0044] Fe X During the preparation of MOFs / CF, the ratio of benzoic acid:4-carboxyphenylporphyrin TCPP:FeCl2 • 6H2O was kept constant at 30:1:5, the amount of cotton fiber CF was fixed at 0.5 g, and the volume of organic solvent (40 mL) was kept constant. The loading rate of MOFs was varied by changing the amount of FeCl2 • 6H2O. XIn -MOFs / CF, the amounts of benzoic acid, 4-carboxyphenylporphyrin TCPP, and FeCl2 • 6H2O are 0.3 g, 0.01 g, 0.05 g; 0.6 g, 0.02 g, 0.10 g; 0.9 g, 0.03 g, 0.15 g; 1.2 g, 0.04 g, 0.20 g; and 1.5 g, 0.05 g, 0.25 g, respectively. X represents the doping amount of FeCl2 • 6H2O, which are 0.05, 0.10, 0.15, 0.20, and 0.25 g, respectively, i.e., Fe... 0.05 -MOFs / CF, Fe 0.10 -MOFs / CF, Fe 0.15 -MOFs / CF, Fe 0.20 -MOFs / CF, Fe 0.25 -MOFs / CF, Fe 0.20 Scanning electron microscope images of MOFs / CF are shown below. Figure 3 (c) and Figure 3 As shown in (d).

[0045] Example 2: The Fe prepared according to the present invention X - MOFs / CF composite materials catalyze the generation of free radicals from hydrogen peroxide (H2O2) under light irradiation for the degradation of tetracycline (TC). Specific steps include:

[0046] (1) Preparation of tetracycline TC stock solution:

[0047] Weigh 100 mg of tetracycline TC into a 1 L beaker, add 800 mL of deionized water, sonicate to dissolve, and then transfer to a 1 L volumetric flask and dilute to volume. Prepare a solution of 100 mg / L. –1 Tetracycline TC stock solution.

[0048] (2) Construction of the standard curve for tetracycline TC solution:

[0049] Dilute the stock solution to different concentration gradients of 1 mg·L⁻¹ –1 5 mg·L –1 10 mg·L –1 30 mg·L –1 50 mg·L –1 The absorbance of different concentrations of TC at 358 nm was then measured using a UV spectrophotometer. Based on the linear relationship between the absorbance of different concentrations of TC at 358 nm and their concentration values, a standard curve was plotted for subsequent calculation of TC concentration.

[0050] (3) Fe X -MOFs / CF catalyzes the degradation of tetracycline TC by H2O2 under light irradiation:

[0051] Add 20 mL of a 50 mg·L⁻¹ solution to the glass bottle. –1 The TC solution was then weighed, followed by 0.004 g of Fe. X MOFs / CF materials were added, followed by 10 mM H2O2 (30%). The xenon lamp light source was 20 cm away from the glass bottle. Under illumination, Fe... X MOFs / CF catalyze the generation of free radicals from H2O2 to degrade and remove TC. Light irradiation can significantly enhance Fe... X - The efficiency of MOFs / CF catalysis in generating free radicals from H2O2. At regular intervals of 0 min, 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min, 1 mL samples were taken and their absorbance was measured using UV light. The TC concentration of the sample was calculated by substituting the absorbance into the standard curve. The ratio of the current concentration to the initial concentration (C) was then used as the basis for the calculation. t The degradation efficiency can be assessed using the CO2 (C0) method. Alternatively, a sample can be taken after 60 minutes of reaction to measure its concentration and calculate the removal rate of TC after 60 minutes of reaction.

[0052] (4) The degradation efficiency of TC at different time periods is represented by C t / C0 indicates that the removal rate is calculated as follows:

[0053] r = (1– C t / C0)× 100%

[0054] (5) Fe composite materials with different doping ratios X -The effect of MOFs / CF light Fenton removal on TC:

[0055] Under the condition of consistent catalyst dosage, light intensity, H2O2 dosage, and TC concentration, the catalytic performance of composite materials with different proportions was compared. 0.004 g of Fe was weighed... 0.05 -MOFs / CF, Fe 0.10 -MOFs / CF, Fe 0.15 -MOFs / CF, Fe 0.20 -MOFs / CF, Fe 0.25 -MOFs / CF were added to 20 mL of a solution containing 50 mg·L⁻¹ –1 In a TC solution, 21.6 μL of 30% H2O2 (10 mM) was added, followed by reaction under xenon lamp irradiation for 60 min. The TC concentration after degradation was measured to calculate the removal rate. Experimental results are as follows: Figure 5 As shown. Fe 0.05 -MOFs / CF, Fe 0.10 -MOFs / CF, Fe 0.15 -MOFs / CF, Fe 0.20-MOFs / CF, Fe 0.25 -MOFs / CF pairs achieved TC removal rates of 86.90%, 92.86%, 97.38%, 98.05%, and 98.57% under photo-Fenton systems. Under the same conditions, Fe... 0.05 -MOFs / CF to Fe 0.15 -MOFs / CF removal rate increases with increasing MOFs doping ratio in composite materials. When the doping ratio further increases (Fe... 0.20 -MOFs / CF to Fe 0.25 -MOFs / CF) removal rate hardly increases anymore, therefore subsequent use of Fe 0.20 Characterization and condition screening of MOFs / CF composites were conducted. Fe with different doping ratios... X The MOFs / CF content and removal rate are shown in the table below:

[0056] Example 3: Fe 0.20 The optimization of the degradation process of the MOFs / CF and H2O2 photo-Fenton system under different pH and dosage conditions is as follows:

[0057] Exploration of pH condition optimization:

[0058] Under the condition that the H2O2 dosage, TC concentration, catalyst usage, light intensity, etc. are kept consistent, the prepared TC solutions are adjusted to pH 2, 4, 6, 8, and 10 by using 0.1 M HCl and 0.1 M NaOH.

[0059] Weigh 0.004 g Fe 0.05 -MOFs / CF, Fe 0.10 -MOFs / CF, Fe 0.15 -MOFs / CF, Fe 0.20 -MOFs / CF, Fe 0.25 -MOFs / CF were added to 20 mL of a solution containing 50 mg·L⁻¹ –1 In a TC solution, 21.6 μL of 30% H2O2 (10 mM) was added, followed by reaction under xenon lamp irradiation for 60 min. The TC removal rates under different pH conditions are as follows: Figure 6As shown in (a), the removal rates of TC by the photo-Fenton system at pH values ​​of 2, 4, 6, 8, and 10 were 83.24%, 98.32%, 97.55%, 76.76%, and 69.45%, respectively. Under excessively acidic conditions, proton-promoted dissolution may lead to partial damage to the material. Under alkaline conditions, H2O2 easily decomposes into O2 and H2O, reducing the production of free radicals. pH 6 is closer to the actual water body, therefore, pH 6 was used subsequently.

[0060] catalyst Fe 0.20 -MOFs / CF usage optimization:

[0061] Add 20 mL of a solution with a concentration of 50 mg·L⁻¹ to a 50 mL glass bottle. –1 The TC solution was then used, and subsequently 0.001 g, 0.002 g, 0.003 g, 0.005 g, and 0.005 g of Fe were weighed out. 0.20 MOFs / CFF materials were added, followed by 21.6 μL of H₂O₂ (10 mM). The glass vial was then placed under xenon lamp irradiation for 60 min, and the TC concentration was measured. Different Fe... 0.20 The effect of MOFs / CF usage on TC removal rate is as follows: Figure 6 As shown in (b), with Fe 0.20 -MOFs / CF dosage from 0.05 g·L –1 Increase by 0.25 g·L –1 The TC removal rate gradually increased. After 60 min of degradation, the catalyst dosage was 0.05 g·L⁻¹. –1 0.10 g·L –1 0.15 g·L –1 0.20 g·L –1 0.25 g·L –1 Fe 0.20 The removal rates of TC by MOFs / CF were 86.23%, 92.07%, 93.97%, 96.11%, and 96.25%, respectively.

[0062] The catalyst dosage was 0.20 g·L⁻¹. –1 0.25 g·L –1 At that time, the removal rate almost reached a plateau, so 0.20 g·L was chosen from a cost perspective. –1 The optimal dosage is [amount to be specified].

[0063] (3) Optimization of H2O2 concentration:

[0064] In ensuring Fe 0.20 -MOFs / CF dosage: 0.20 g·L –120 mL of TC concentration is 50 mg·L –1 Under identical conditions (pH=6, light exposure, etc.), the amount of H2O2 added was varied. 10.8 μL, 21.6 μL, 43.2 μL, 64.8 μL, and 86.4 μL of H2O2 were added to the solution, corresponding to 5 mM, 10 mM, 20 mM, 30 mM, and 40 mM, respectively. The glass bottle was then placed under a xenon lamp for 60 min, and the concentration of TC solution after the reaction was measured. The results are as follows: Figure 6 As shown in (c), the TC removal rates after 50 min of H2O2 usage (5 mM, 10 mM, 20 mM, 30 mM, 40 mM) were 88.24%, 95.66%, and 97.84%, respectively.

[0065] The removal rates of TC increased with the increase of H2O2 concentration, reaching 98.67% and 98.99%, eventually plateauing. From an economic cost perspective, 30 mM was chosen as the final dosage.

[0066] (4) The ability of the photo-Fenton system to degrade different TC concentrations:

[0067] To investigate the degradation ability of this photo-Fenton system for different concentrations of TC, while ensuring Fe... 0.20 -MOFs / CF dosage: 0.20 g·L –1 Under identical conditions (pH=6, H₂O₂ dosage 30 mM, TC solution volume 20 mL, light conditions, etc.), different concentration gradients of TC were set up, each with a concentration of 10 g·L⁻¹. –1 30 g·L –1 50 g·L –1 70 g·L –1 100 g·L –1 The removal rate was calculated by measuring the TC solution concentration after 60 minutes of reaction. The results are as follows: Figure 6 As shown in (d), this optical Fenton system is effective against 10 g·L⁻¹. –1 30 g·L –1 50 g·L –1 70 g·L –1 100 g·L –1 The removal rates of TC solutions were 97.56%, 98.72%, 98.69%, 96.09%, and 95.32%, respectively. The results indicate that this photo-Fenton system has good removal effects on both low-concentration and high-concentration TC solutions.

[0068] Example 4: Investigating the removal effect of TC under different systems, mainly examining whether single-factor variables affect TC degradation and the adsorption performance, Fenton-like performance, photocatalytic performance, and photo-Fenton performance of the materials, specifically including the following steps:

[0069] (1) The degradation effect of H2O2 on TC:

[0070] 64.8 μL of H2O2 (30 mM) was added to 20 mL of a solution with a concentration of 50 mg·L⁻¹. –1 In the TC solution, the concentration was measured by sampling every 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min. t / C0 is used to assess its degradation efficiency, and the degradation process is as follows: Figure 7 As shown in (a), the TC removal rate was only 0.57% after 60 min of degradation, as indicated in the results. Figure 7 As shown in (b). The results show that simply adding H2O2 (30 mM) does not induce the generation of free radicals to degrade TC.

[0071] (2) The degradation effect of light on TC:

[0072] To investigate the effect of light on degradation performance, a xenon lamp source was directly irradiated with 20 mL of a 50 mg·L⁻¹ solution. –1 The concentration change of the TC solution was checked every 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min using C. t / C0 is used to assess its degradation efficiency as follows: Figure 7 As shown in (a), the TC removal rate was only 4.24% after 60 min of degradation, as indicated in the results. Figure 7 As shown in (b), the results indicate that light exposure affects TC concentration.

[0073] (3) The degradation effect of light + H2O2 on TC:

[0074] To investigate the effect of the combination of light and H2O2 on TC degradation, 64.8 μL of H2O2 (30 mM) was added to 20 mL of a solution with a concentration of 50 mg·L⁻¹. –1 The solution was placed in a TC solution and irradiated under a xenon lamp. The concentration was measured at 10, 20, 30, 40, 50, and 60 minutes using CT. t / C0 is used to assess its degradation efficiency, and the degradation process is as follows: Figure 7 As shown in (a), the TC removal rate was 12.04% after 60 min of degradation, as shown in the results. Figure 7As shown in (b). The results show that the combination of light and H2O2 has a significantly better degradation ability for TC than H2O2 alone or light alone, indicating that light can stimulate H2O2 to generate a small portion of free radicals for TC degradation.

[0075] (4) Adsorption and removal effect of catalyst on TC:

[0076] To evaluate the adsorption performance of the catalyst itself and its proportion of TC removal in the photo-Fenton system, its adsorption performance was investigated by adding only the catalyst to the TC solution. 0.004 g of catalyst Fe... 0.20 -MOFs / CF were added to a 20 mL volume at a concentration of 50 mg·L⁻¹. –1 The concentration change of the TC solution was checked every 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min using C. t / C0 is used to assess its degradation efficiency as follows: Figure 7 As shown in (a), the TC removal rate was only 8.03% after 60 min of degradation, as indicated in the results. Figure 7 As shown in (b), the results indicate that the catalyst itself has a low adsorption capacity for TC.

[0077] (5) Degradation effect of catalyst + photocatalysis system on TC:

[0078] To evaluate the role of the catalyst + light photocatalytic system in photo-Fenton, 0.004 g of catalyst Fe was used. 0.20 -MOFs / CF were added to a 20 mL volume at a concentration of 50 mg·L⁻¹. –1 The TC solution was irradiated with a xenon lamp, and its concentration change was checked every 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min using C. t / C0 is used to assess its degradation efficiency, and the degradation process is as follows: Figure 7 As shown in (a), the TC removal rate was 14.24% after 60 min of degradation, as shown in the results. Figure 7 As shown in (b). The results indicate that the photocatalytic system has a certain degradation effect, suggesting that light can excite electron-hole separation for TC degradation. However, electron-hole recombination is common, resulting in a lower degradation effect; therefore, photocatalysis does not play a dominant role. Photocatalytic reaction formula:

[0079] Fe 0.20 -MOFs / CF+hν → h + +e - (1)

[0080] (6) Degradation effect of H2O2+ catalyst-based Fenton system on TC:

[0081] 0.004 g of catalyst Fe 0.20 -MOFs / CF were added to a 20 mL volume at a concentration of 50 mg·L⁻¹. –1 The TC solution was prepared and 64.8 μL of H2O2 (30 mM) was added. The concentration change was checked every 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min using C. t / C0 is used to assess its degradation efficiency, and the degradation process is as follows: Figure 7 As shown in (a). Fe 2+ It can activate H2O2 to generate hydroxyl radicals, which are used for TC degradation. The reaction formula is as follows:

[0082] Fe 2+ +H₂O₂ → Fe 3+ +·OH+OH − (2)

[0083] Fe 3+ +H₂O₂ → Fe 2+ +·OOH+H + (3)

[0084] Fe in Fenton-like reactions 2+ It reacts with H2O2 to produce Fe 3+ The rate is extremely fast, however, Fe 3+ Reduced to Fe 2+ The rate is extremely slow, resulting in Fe... 2+ Rapid depletion, Fe 3+ Accumulation. In this embodiment, the degradation effect of the H2O2+ catalyst-like Fenton system on TC is as follows: Figure 7 As shown in (b), the TC removal rate was 58.86% after 60 min of degradation. The results indicate that although the Fenton-like system plays a dominant role in the TC degradation process, Fe... 2+ / Fe 3+ There is still room for improvement in the cyclical process.

[0085] (7) The degradation effect of the light + catalyst + H2O2 photo-Fenton system on TC:

[0086] 0.004 g of catalyst Fe 0.20 -MOFs / CF were added to a 20 mL volume at a concentration of 50 mg·L⁻¹. –1 A TC solution was prepared and 64.8 μL of H2O2 (30 mM) was added. The reaction was carried out under xenon lamp illumination, and the concentration change was checked every 10 min, 20 min, 30 min, 40 min, 50 min, and 60 min via C. t / C0 is used to assess its degradation efficiency, and the degradation process is as follows: Figure 7As shown in (a), the reaction equation for the photo-Fenton system is as follows:

[0087] Fe 2+ +H₂O₂ → Fe 3+ +·OH+OH − (2)

[0088] Fe 3+ +H₂O₂ → Fe 2+ +·OOH+H + (3)

[0089] Fe 0.20 -MOFs / CF+hν → h + +e - (1)

[0090] Fe 3+ +e - → Fe 2+ (4)

[0091] In the photo-Fenton reaction, light can excite electron-hole separation, and the generated electrons can be absorbed by Fe. 3+ Consumption thus promotes Fe in Fenton-like reactions 2+ / Fe 3+ Circular solution of Fe 2+ Rapid consumption of Fe 3+ The accumulation of electrons and the difficulty of hole recombination after electron consumption also enhances photocatalytic performance. In this embodiment, the degradation effect of the H2O2 + catalyst + light-based Fenton-like system on TC is as follows: Figure 7 As shown in (b), the TC removal rate was 99.13% after 60 min of degradation, indicating that the photo-Fenton system can efficiently degrade and remove TC. The TC degradation process data for different reaction systems are shown in the table below:

[0092] Removal rate r of TC for different reaction systems at various time periods: r = (1 - C t / C0)*100%, detailed data is shown in the table below:

[0093]

[0094] Example 5: The photo-Fenton system degrades other organic pollutants. Specific steps:

[0095] Preparation of 50 mg·L –1 Other organic contaminants in the solution. Other organic contaminants include methyl orange (MO), methylene blue (MB), norfloxacin (NFX), enrofloxacin (ENR), and oxytetracycline (OTC). 0.004 g of catalyst Fe... 0.20-MOFs / CF were added to a 20 mL volume at a concentration of 50 mg·L⁻¹. –1 Methyl orange (MO), methylene blue (MB), norfloxacin (NFX), enrofloxacin (ENR), and oxytetracycline (OTC) solutions were added, and 64.8 μL of H₂O₂ (30 mM) was added. The mixture was reacted under xenon lamp illumination, and its concentration changes were monitored at 10, 20, 30, 40, 50, and 60 min using C0. t / C0 is used to assess its degradation efficiency, and the degradation process is as follows: Figure 6 As shown in the table, after 60 min of reaction, the removal rates of methyl orange (MO), methylene blue (MB), norfloxacin (NFX), enrofloxacin (ENR), and oxytetracycline (OTC) were 51.28%, 99.41%, 87.84%, 65.33%, and 97.31%, respectively. This indicates that the photo-Fenton system has a good degradation and removal effect on other organic pollutants. Detailed data on the degradation process over time are shown in the table below:

[0096] The table below shows the changes in the removal rate of other organic pollutants by the photo-Fenton system over time:

[0097] This invention uses the environmentally friendly photosensitive material 4-carboxyphenylporphyrin TCPP as an organic ligand, Fe 2+ Nano-Fe-MOFs prepared with a metal center exhibit excellent photo-Fenton catalytic performance, enabling rapid and efficient removal of tetracycline (TC) and other organic pollutants. The enhanced photo-Fenton degradation performance is primarily attributed to the separation of photo-excited electrons and holes; photogenerated electrons promote the degradation of Fe in Fenton-like structures. 3+ The reduction process, similar to Fenton's process, consumes electrons, making it difficult for electrons and holes to recombine, thus promoting the photocatalytic degradation process. The synergistic effect of photocatalysis and Fenton's process greatly promotes the generation of free radicals and efficiently degrades organic matter; for example, methylene blue (MO) can achieve a removal rate of 99.41% within 60 minutes.

[0098] In addition, this invention also involves the technology of combining nano-Fe-MOFs with bio-based cotton fibers, mainly including plasma cleaning, alkalization treatment, and carboxymethyl treatment. Loading these nano-Fe-MOFs onto bio-based fiber (CF) can effectively prevent the aggregation of nano-Fe-MOFs and improve their catalytic efficiency. Compared with traditional powdered catalytic materials, the three-dimensional structure of the composite material... 0.20 -MOFs / CF are easy to recycle after use, which greatly improves the actual performance of this material. Fe 0.20The photo-Fenton degradation system of MOFs / CF + light + H2O2 has the advantages of fast degradation rate, high removal rate, green environmental protection and easy recycling, and has been successfully used for the degradation of tetracycline TC and other organic pollutants.

[0099] It should be noted that although this patent document describes the invention using a multi-example approach, this does not mean that each example involves only a single technical solution. This approach is solely for clarity of explanation, and those skilled in the art should understand the content of the specification from an overall perspective. In fact, the technical solutions disclosed in each embodiment can be reasonably combined according to actual needs to form other technical solutions that can be implemented by those skilled in the art.

[0100] The detailed embodiments described above are merely specific illustrations of feasible implementations of the present invention and are not intended to limit the scope of protection of the present invention. Any equivalent substitutions or modifications made based on the core technical concept of the present invention should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing a nano-MOFs-supported bio-based fiber photoFenton catalytic material, characterized in that, Includes the following steps: Step S1, Pretreatment of bio-based cotton fiber (CF): The cleaned cotton fiber CF was plasma cleaned for 60 seconds, followed by alkalization to activate the cellulose in the cotton fiber CF, and finally carboxymethylation of the cotton fiber CF. This series of measures is beneficial for loading metal-organic frameworks (MOFs). Step S2, Fe nano-MOFs bio-based fiber composite material X Preparation of MOFs / CF: Will The cotton fibers CF pretreated in step S1 were dissolved in an organic solvent, and then impregnated in the organic solvent for 8 hours; subsequently, benzoic acid and 4-carboxyphenylporphyrin TCPP were dissolved in the solvent, and the ratio of benzoic acid:4-carboxyphenylporphyrin TCPP: Fe was prepared by hydrothermal reaction at 90℃ for 5 h with a ratio of 30:1:

5. X -MOFs / CF; then the prepared Fe X - The MOFs / CF were first dried and then washed with ethanol to remove undissolved ligands, yielding the final nano-MOFs bio-based fiber composite material Fe. X -MOFs / CF; Fe X In MOFs / CF, X represents... Doping amount; In this step, maintain benzoic acid: 4-carboxyphenylporphyrin TCPP: The ratio of 30:1:5 remains unchanged, and the volume of the organic solvent is not altered. The change is achieved by altering... The amount of MOFs is used to change the loading rate of CF in cotton fibers.

2. The method for preparing the nano-MOFs-supported bio-based fiber photoFenton catalytic material according to claim 1, characterized in that, In step S1, the alkalization treatment is to swell the cotton fiber CF and activate the cellulose to facilitate better carboxymethylation. The alkali is a 20%~30% mass ratio NaOH solution, and 50 ml of NaOH solution corresponds to 0.5 g~1.0 g of cotton fiber CF. Stir at room temperature (25~30℃) for 1~3 h.

3. The method for preparing the nano-MOFs-supported bio-based fiber photoFenton catalytic material according to claim 1, characterized in that, In step S1, carboxymethylation is used to improve the binding of MOFs to cotton fiber CF; 50 ml of 20%~30% chloroacetic acid solution corresponds to 0.5 g~1.0 g of cotton fiber CF, and the reaction is carried out at 50℃~70℃ for 2 h~4 h.

4. The method for preparing the nano-MOFs-supported bio-based fiber photoFenton catalytic material according to claim 1, characterized in that, In step S2, the organic solvent is either N,N-dimethylformamide or ethanol.

5. The method for preparing the nano-MOFs-supported bio-based fiber photoFenton catalytic material according to claim 1, characterized in that, In step S2, X is 0.05~0.

25.

6. The method for preparing the nano-MOFs-supported bio-based fiber photoFenton catalytic material according to claim 5, characterized in that, In step S2, X is 0.2, i.e., benzoic acid, 4-carboxyphenylporphyrin TCPP. The amounts were 1.2 g, 0.04 g, and 0.20 g, respectively. The nano-MOFs bio-based fiber composite material was Fe. 0.2 -MOFs / CF.

7. The application of a nano-MOFs bio-based fiber composite material prepared by the method according to any one of claims 1-6 for photo-Fenton degradation of tetracycline TC and other organic pollutants.

8. The application of the nano-MOFs bio-based fiber composite material according to claim 7 in the photo-Fenton degradation of tetracycline TC and other organic pollutants, characterized in that, Other organic pollutants include methyl orange (MO), methylene blue (MB), norfloxacin (NFX), enrofloxacin (ENR), and oxytetracycline (OTC).

9. The application of the nano-MOFs bio-based fiber composite material according to claim 7 in the photo-Fenton degradation of tetracycline TC and other organic pollutants, characterized in that, Applications of photo-enhanced composite materials catalyzing the generation of free radicals from hydrogen peroxide (H2O2) to oxidize and degrade tetracycline (TC) and other organic pollutants. Includes the following steps: Weigh out Fe from the nano-MOFs bio-based fiber composite material 0.2 MOFs / CF are added to the water to be treated, which contains tetracycline (TC) and other organic pollutants. Hydrogen peroxide (H₂O₂) is then added to adjust the pH. A xenon lamp source is introduced, and the MOFs bio-based fiber composite material (Fe) is then applied. 0.2 -MOFs / CF catalyze the generation of free radicals from H2O2 under light conditions to degrade and remove tetracycline (TC) and other organic pollutants.

10. The application of the nano-MOFs bio-based fiber composite material according to claim 9 in the photo-Fenton degradation of tetracycline TC and other organic pollutants, characterized in that, The MOFs bio-based fiber composite material Fe 0.2 The MOFs / CF dosage was 0.05 g·L⁻¹. –1 ~0.25 g·L –1 Hydrogen peroxide (H₂O₂) usage: 5 mM ~ 40 mM; pH: 2 ~ 10; Organic pollutant: 10 mg·L⁻¹ –1 ~100 mg·L –1 Xenon lamp illumination intensity: 100 mW / cm².

Images