Preparation method and application of carbon-based fiber-loaded MOF-derived Co3O4 catalytic material
By growing MOF precursors in situ on carbon-based fibers and calcining them into Co3O4, the separation and activity problems of powdered catalysts in water treatment were solved, and the preparation of carbon-based fiber-supported Co3O4 catalytic materials for the efficient degradation of antibiotics was realized, exhibiting good catalytic performance and stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANCHANG UNIV
- Filing Date
- 2026-03-31
- Publication Date
- 2026-05-05
AI Technical Summary
Existing powdered persulfate catalysts are difficult to separate and recover quickly in water treatment, are prone to agglomeration, have insufficient exposure of active sites, and exhibit rapid activity decay in complex water bodies. They also suffer from high mass transfer resistance in engineered devices. Furthermore, the active phase distribution is uneven after existing MOF precursors are combined with carbon-based fibers, and improper calcination temperature control leads to poor performance.
By growing MOF precursors in situ on the surface of carbon-based fibers and calcining them into Co3O4 at different temperatures, a carbon-based fiber-supported Co3O4 composite catalytic material with strong interfacial bonding and controllable structure is formed, which is used for persulfate-activated degradation of antibiotic pollutants.
It achieves high activity, high stability and easy assembly of catalytic materials, can effectively degrade antibiotics such as levofloxacin, avoids the defects of powder catalysts, has good operability and recyclability, and is suitable for complex aquatic environments.
Smart Images
Figure CN121972166A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of environmental catalytic materials and advanced oxidation technology, specifically relating to a carbon-based fiber-supported Co3O4 composite catalytic material obtained by calcination conversion using carbon-based fibers as a carrier and metal-organic framework (MOF) materials as precursors, as well as its preparation method and application in the persulfate-activated degradation of antibiotic pollutants, belonging to the field of advanced oxidation. Background Technology
[0002] In recent years, advanced oxidation technologies have become an important direction for removing recalcitrant organic pollutants due to their ability to generate highly active free radicals or non-free radical active species in situ. Among them, persulfate-based oxidation systems have attracted widespread attention due to their strong oxidizing power, wide applicable pH range, and efficient activation through transition metal catalysts. During persulfate activation, active species such as sulfate radicals, hydroxyl radicals, and singlet oxygen can be induced on the catalyst surface, thereby achieving rapid degradation of antibiotic pollutants such as levofloxacin. However, traditional persulfate activation catalysts are mostly powdered materials, which generally have the following shortcomings: First, powdered catalysts are difficult to separate and recover quickly in water treatment systems, resulting in poor reusability; second, powdered materials are prone to agglomeration during actual reactions, leading to insufficient exposure of effective active sites; third, powdered catalysts are easily affected by inorganic ions, organic coexistences, and natural organic matter in complex aquatic environments, resulting in rapid activity decay; fourth, powdered materials require additional carriers, binders, or immobilization processes in engineered devices, increasing assembly difficulty and potentially causing increased mass transfer resistance.
[0003] To address the aforementioned challenges of powdered catalysts in practical applications, developing a morphologically formed catalytic material that combines high activity, high stability, ease of assembly, and excellent mass transfer capabilities is crucial. Carbon-based fibers, as a flexible carbon-based conductive substrate, possess a three-dimensional interwoven fiber network structure, good mechanical strength, excellent conductivity, and a large specific surface area. Furthermore, their surface typically contains a certain number of oxygen-containing functional groups, which facilitates the anchoring and growth of metals or metal oxides. Therefore, carbon-based fibers can serve as excellent catalyst supports or frameworks for constructing integrated, recyclable, easily cut, and assembleable morphologically formed catalytic materials.
[0004] On the other hand, metal-organic frameworks (MOFs) have attracted widespread attention in catalysis, separation, and energy storage due to their advantages such as tunable pore structure, uniform metal site distribution, large specific surface area, and designable chemical composition. In particular, MOF precursors constructed from metal ions and organic ligands can be transformed into metal oxides, metal / carbon composites, or porous derivatives through pyrolysis, calcination, or carbonization, thus combining the designability of MOFs with the stability and activity of derived materials. Among them, ZIF-67, as a typical cobalt-containing MOF material, is widely used in constructing cobalt-based functional materials because of its stable crystal structure, mild synthesis conditions, ease of in-situ growth on carbon-based fiber surfaces, and ability to form cobalt-based oxides such as Co3O4 after thermal conversion.
[0005] However, existing reports on the conversion of MOF precursors into cobalt oxides by combining them with carbon-based fibers and then reheating them still have several shortcomings: First, the growth uniformity and adhesion strength of MOF precursors on carbon-based fibers are limited, leading to uneven distribution of the active phase after subsequent calcination; second, the effects of different calcination temperatures on the material's grain size, pore structure, interfacial bonding, and exposure of active sites lack systematic regulation; third, existing materials often only focus on a single temperature point or a single performance evaluation, lacking in-depth design of the coupling relationship between "temperature-structure-performance"; fourth, existing systems may still suffer from insufficient activity, poor structural stability, or rapid performance degradation when continuously degrading antibiotic pollutants such as levofloxacin.
[0006] Therefore, there is an urgent need to provide a carbon fiber-supported Co3O4 composite catalytic material based on MOF precursors, especially based on cobalt-containing MOF precursors, and its preparation method. By precisely controlling the calcination temperature, a morphological catalytic material with excellent structural controllability, active site distribution, and sustained catalytic ability can be obtained to solve the defects of existing powder catalysts and conventional supported catalysts in practical applications. Summary of the Invention
[0007] The present invention aims to provide a method for preparing and applying a carbon-based fiber-supported MOF-derived Co3O4 catalytic material. The method utilizes carbon-based fibers as a substrate and MOF precursors as intermediates, converting them into Co3O4 through calcination to obtain a carbon-based fiber-supported Co3O4 composite catalytic material. This method involves in-situ growth of MOF precursors on the surface of carbon-based fibers and calcination at different temperatures to convert them into Co3O4, thereby obtaining a composite catalytic material with good interfacial bonding, tunable structure, and excellent catalytic activity. This material is used for the persulfate-activated degradation of antibiotic pollutants, and is particularly suitable for the removal of levofloxacin.
[0008] To achieve the above objectives, the present invention adopts the following technical solution.
[0009] The present invention discloses a method for preparing a carbon-based fiber-supported MOF-derived Co3O4 catalytic material, comprising the following steps:
[0010] (1) After cutting the carbon fiber substrate material to a predetermined size, it is ultrasonically cleaned with deionized water, ethanol and / or acetone in sequence to remove oil, dust and other impurities attached to the surface of the material; after cleaning, it is air-dried or vacuum-dried for later use to improve the nucleation ability and adhesion stability of the subsequent MOF precursor on its surface.
[0011] The carbon fiber substrate material is preferably one or more of carbon cloth, carbon fiber fabric, carbon fiber woven fabric, carbon fiber felt, carbon fiber paper, carbon fiber nonwoven fabric, carbon fiber mesh, or carbon fiber film, and is more preferably carbon cloth.
[0012] (2) The pretreated carbon-based fiber is placed in a reaction system containing a metal source and an organic ligand, so that the MOF precursor is generated in situ on the surface of the carbon-based fiber, thereby obtaining a carbon-based fiber-supported MOF precursor composite material.
[0013] Preferably, the MOF precursor is a cobalt-containing MOF; more preferably, the cobalt-containing MOF is ZIF-67.
[0014] (3) The carbon-based fiber-supported MOF precursor composite material is placed in an inert atmosphere and calcined at 400℃~800℃ to convert the MOF precursor into a Co3O4 composite catalyst material.
[0015] Preferably, the calcination temperature is 600℃; the heating rate is preferably 5℃ / min; and the holding time is preferably 2h.
[0016] The present invention relates to the application of carbon-based fiber-supported MOF-derived Co3O4 catalytic material in the degradation of organic pollutants by activated persulfate.
[0017] Preferably, the organic pollutant is an antibiotic.
[0018] Preferably, the antibiotic is levofloxacin.
[0019] Compared with the prior art, the present invention has at least the following beneficial effects:
[0020] (1) In-situ growth and strong interfacial bonding: The MOF precursor crystallizes and grows in situ on the surface of carbon fiber, which reduces peeling and agglomeration during subsequent calcination and enhances the interfacial interaction between the active phase and the support.
[0021] (2) Controllable structure and adjustable performance: By adjusting the calcination temperature, the grain size of Co3O4, the different collapse modes of MOF dodecahedrons and their distribution can be controlled, thereby adjusting the morphology and performance of the material.
[0022] (3) Convertibility of MOF to oxide: MOF precursors have good structural designability and convertibility. Highly dispersed cobalt oxides can be formed by calcination, which improves the utilization rate of active sites.
[0023] (4) Applicable to antibiotic pollutant degradation: The material can efficiently generate active species in the persulfate activation system, and has an excellent removal effect on refractory antibiotics such as levofloxacin.
[0024] (5) Avoiding the drawbacks of powder catalysts: Compared with traditional powder catalysts, the material of the present invention is a morphological catalytic material, which has better operability, recyclability and engineering application potential.
[0025] (6) The preferred calcined sample at 600℃ has a better balance between activity, stability and structural integrity, and has better overall performance, making it more suitable for the efficient degradation of antibiotics such as levofloxacin. Attached Figure Description
[0026] Figure 1 Photograph of a MOF-derived Co3O4 composite catalyst supported on a carbon fiber substrate prepared at calcination temperature of 600℃.
[0027] Figure 2 Scanning electron microscope (SEM) images of samples loaded with ZIF-67 and calcined at 400℃, 600℃ and 800℃.
[0028] Figure 3 This is a high-resolution transmission electron microscope (HRTEM) image of the MOF-derived Co3O4 composite catalyst material supported on a carbon fiber substrate prepared at a calcination temperature of 600℃ in Example 1.
[0029] Figure 4 The X-ray diffraction (XRD) patterns of different samples in Example 1 are shown.
[0030] Figure 5 Performance spectra of the catalytic materials prepared in Example 1 and Comparative Examples 1 and 2 for activating persulfate to degrade levofloxacin;
[0031] Figure 6 The performance spectrum of the catalytic material prepared in Example 1 for activating persulfate degradation of various antibiotics is shown.
[0032] Figure 7 The image shows a comparison of the catalyst material prepared in Example 1 at a calcination temperature of 600℃ before and after its reaction in treating medical wastewater. Detailed Implementation
[0033] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The following content is merely illustrative and explanatory of the inventive concept. Various modifications or additions to the described specific embodiments by those skilled in the art, or the use of similar methods to replace them, shall fall within the protection scope of the present invention as long as they do not depart from the inventive concept or exceed the scope defined by the claims.
[0034] Example 1: Preparation of carbon-based fiber-supported MOF-derived Co3O4 catalytic material.
[0035] The preparation of carbon-based fiber-supported MOF-derived Co3O4 catalytic materials includes the following steps:
[0036] (1) Cut the carbon fiber substrate material into 1.0cm×1.0cm sheet samples, place them in an ultrasonic cleaner, and ultrasonically clean them sequentially with deionized water and ethanol. The cleaning time for each solvent is 10-20 minutes to remove impurities and oil stains attached to the material surface. After cleaning, take out the samples and let them air dry at room temperature or place them in a vacuum drying oven at 60℃ for later use.
[0037] Preparation of precursor growth solutions: 2-methylimidazole and sodium hydroxide were dissolved in 50 mL of ultrapure water to obtain solution A; cobalt nitrate hexahydrate was dissolved in 10 mL of ultrapure water to obtain solution B. The pretreated carbon fiber substrate was placed in solution A, and solution B was added dropwise to solution A at a rate of 0.17 mL / min using a micro-injection pump under magnetic stirring.
[0038] After the addition was complete, the reaction continued for 6 hours, and the MOF precursor ZIF-67 was grown in situ on the surface of the carbon fiber substrate by co-precipitation. After the reaction was completed, the obtained material was taken out and washed three times with methanol and ultrapure water to remove unbound particles and residual precursor substances. Then it was placed in a vacuum drying oven at 60℃ for 12 hours to obtain a carbon fiber substrate-supported MOF precursor composite material.
[0039] (2) The carbon-based fiber-supported MOF precursor composite material obtained in step (1) is placed in a tube furnace and calcined under a nitrogen or other inert gas atmosphere. The preferred heating rate is 5℃ / min, and the temperature is raised to 600℃ and held at the target temperature for 2 hours. After calcination, it is naturally cooled to room temperature to obtain the carbon-based fiber-supported Co3O4 composite catalyst material, denoted as CC@MOF-600-Co3O4. If ZIF-67 is used as the precursor, the corresponding sample can be denoted as CC@Z-600-Co3O4.
[0040] During calcination, the MOF precursor decomposes and generates Co3O4, while some carbonaceous structures are retained or transformed, forming a composite interface tightly coupled with carbon-based fibers. For example... Figure 1 The image shown is a photograph of the sample prepared in this embodiment at a calcination temperature of 600℃. It can be seen that the obtained material maintains good flexibility and structural integrity, without significant damage or pulverization, indicating that the preparation method can achieve stable loading of active components while maintaining the macroscopic structure of the carbon fiber substrate material.
[0041] When calcined at 600℃, the MOF precursor can be fully converted into well-crystallized Co3O4 while maintaining good dispersibility and a reasonable pore structure. At this temperature, the interfacial bonding between Co3O4 and carbon-based fibers is relatively stable, the electron transport pathway is smooth, and the active sites are sufficiently exposed, typically achieving a good balance between catalytic activity and structural stability. Therefore, samples calcined at 600℃ are usually preferred as representative samples with the best overall performance. Figure 3 The image shown is a high-resolution transmission electron microscope (HRTEM) image of the sample calcined at 600℃. Clear lattice fringes are visible in the image, indicating that the Co3O4 in this sample has good crystallinity. Simultaneously, the close interfacial contact between the Co3O4 nanostructure and the carbon fiber substrate facilitates electron transfer between the active phase and the support, thereby improving the catalytic reaction efficiency.
[0042] like Figure 4 The X-ray diffraction (XRD) patterns of carbon cloth loaded with ZIF-67 and samples calcined at different temperatures are shown. The results indicate that the co-precipitated MOF material was successfully loaded onto carbon fibers, and all samples formed the characteristic Co3O4 crystalline phase after calcination. Differences in diffraction peak intensity and shape at different calcination temperatures suggest variations in crystallinity and grain size. The sample calcined at 600℃ exhibited moderate crystallinity and strong diffraction peaks, indicating a well-developed crystal structure.
[0043] Compared to Example 1, different calcination temperatures cause variations in material grain growth, pore structure collapse or optimization, changes in residual carbon content, and differences in surface oxygen vacancies and defect concentrations, thus significantly impacting subsequent catalytic performance. For example... Figure 2The image shows scanning electron microscope (SEM) images of ZIF-67 and samples calcined at different temperatures (400℃, 600℃, and 800℃). The images reveal significant differences in the surface morphology of the materials under different conditions. The ZIF-67-loaded carbon fibers are fully grown with a dodecahedral metal-organic framework. In the 400℃ sample, the particle size is small but the distribution is not uniform. In the 600℃ sample, the Co3O4 particles are uniformly distributed and well-adhered, without obvious agglomeration. In the 800℃ sample, the bottom layer of the Co3O4 precursor structure is still preserved, while the outermost particles show significant growth and localized sintering, resulting in a denser surface structure.
[0044] In this invention, calcination temperature is one of the key factors affecting the material structure and catalytic performance. Specifically:
[0045] Comparative Example 1: Low-temperature calcined sample
[0046] like Figure 2 As shown, when the calcination temperature is low, such as 400℃, the decomposition of the MOF precursor is relatively limited, resulting in smaller Co3O4 grains, which may be accompanied by a certain amount of residual organic carbon or semi-carbonized structures. This sample typically has more surface defects and a higher specific surface area, which is beneficial for the adsorption and activation of pollutants, but its crystallinity and long-term stability may be relatively insufficient.
[0047] Comparative Example 2: High-Temperature Calcination Sample
[0048] like Figure 2 As shown, when the calcination temperature is further increased, for example to 800℃, Co3O4 grains may grow significantly, accompanied by a decrease in specific surface area and partial collapse of the pore structure, resulting in higher leaching of heavy metal Co and causing secondary pollution of water bodies. Although the thermal stability and crystal integrity of the sample may be improved, excessive sintering often leads to a reduction in surface active sites and poor dispersibility, thereby reducing catalytic activity.
[0049] Example 3: Performance difference analysis of samples at different temperatures.
[0050] The prepared carbon fiber substrate material loaded with Co3O4 composite catalyst was used to activate persulfate to degrade the antibiotic levofloxacin. A certain amount of catalyst was added to an aqueous solution containing levofloxacin, and persulfate was added as an oxidant. The reaction was carried out with stirring at room temperature, and samples were taken periodically to analyze changes in pollutant concentration. Figure 5The figure shows the performance spectrum of the sample calcined at 600℃ in the persulfate system for the degradation of levofloxacin. The results indicate that this catalytic material can effectively activate persulfate and rapidly degrade levofloxacin, exhibiting excellent catalytic activity. In contrast, the samples calcined at 400℃ and 800℃ showed lower degradation efficiencies under the same conditions. This result further illustrates that calcination temperature is a crucial parameter affecting the catalytic performance of MOF-derived carbon fiber-supported Co3O4 materials.
[0051] Example 4: Practical application degradation performance and analysis of CC@Z-600-Co3O4 sample
[0052] Furthermore, such as Figure 6 As shown, the catalytic material exhibits good degradation effects on various antibiotics such as tetracycline, sulfadiazine, levofloxacin, and ciprofloxacin hydrochloride in a persulfate system, indicating that it has strong broad-spectrum applicability.
[0053] To verify the performance of the material of this invention in actual complex water bodies, samples calcined at 600℃ were used in a medical wastewater treatment experiment. For example... Figure 7 The image shows a comparison of medical wastewater before and after the reaction. It can be seen that the color and turbidity of the water were significantly reduced after treatment, and the odor was significantly improved. This indicates that the pollutants were effectively removed. These results demonstrate that the carbon fiber substrate-supported MOF-derived Co3O4 composite catalyst prepared in this invention has good application potential in practical wastewater treatment.
[0054] In summary, by controlling the calcination temperature, a balance can be achieved between the crystallinity, defect concentration, specific surface area, conductivity, and interfacial bonding of the material, so as to obtain carbon-based fiber-supported Co3O4 composite catalytic materials suitable for different reaction requirements.
[0055] The above are merely exemplary embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing a carbon-based fiber-supported MOF-derived Co3O4 composite catalytic material, characterized in that, Includes the following steps: (1) The carbon-based fiber substrate material is pretreated to obtain pretreated carbon-based fibers; (2) The pretreated carbon-based fibers are placed in a reaction system containing a metal source and organic ligands to generate MOF precursors in situ on the surface of the carbon-based fibers, thereby obtaining carbon-based fiber-supported MOF precursor composite materials. (3) The carbon fiber supported MOF precursor composite material is placed in an inert atmosphere and calcined at 400℃~800℃ to convert the MOF precursor into Co3O4, thereby obtaining carbon fiber supported Co3O4 composite catalyst material.
2. The preparation method according to claim 1, characterized in that, The carbon-based fiber substrate material mentioned in step (1) is carbon cloth, carbon fiber fabric, carbon fiber felt or carbon fiber paper.
3. The preparation method according to claim 1, characterized in that, The MOF precursor mentioned in step (2) is ZIF-67.
4. The preparation method according to claim 4, characterized in that, The calcination temperature is 600℃.
5. A carbon-based fiber-supported MOF-derived Co3O4 composite catalytic material, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 5.
6. The carbon-based fiber-supported MOF-derived Co3O4 composite catalytic material according to claim 5, characterized in that, The Co3O4 is loaded on the surface of the carbon fiber and forms an interface bond with the carbon fiber.
7. The application of the carbon-based fiber-supported MOF-derived Co3O4 composite catalytic material as described in claim 5 or 6 in the degradation of organic pollutants by activated persulfate.
8. The application according to claim 7, characterized in that, The organic pollutant is an antibiotic.
9. The application according to claim 8, characterized in that, The antibiotic in question is levofloxacin.