A Fe3O4-CuO graphene oxide composite, its preparation method and application
By preparing Fe3O4-CuO graphene oxide composite, the problems of low oxidation efficiency of photocatalysts and the difficulty in degrading tetracycline pollutants were solved, realizing efficient catalytic degradation and catalyst recycling, which is suitable for water pollution treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GUANGXI ACAD OF SCI
- Filing Date
- 2026-04-02
- Publication Date
- 2026-06-09
AI Technical Summary
Existing photocatalysts have low oxidation efficiency and are difficult to recycle, and tetracycline antibiotic pollutants in water are difficult to degrade.
A Fe3O4-CuO graphene oxide composite was prepared by combining Fe3O4 and CuO with graphene oxide to form a composite material with high catalytic activity, magnetism and good stability, which can be used for the catalytic degradation of tetracycline.
It significantly improves the degradation efficiency of tetracycline, enables efficient recovery and recycling of the catalyst, reduces treatment costs, and is suitable for water pollution treatment under visible light conditions.
Smart Images
Figure CN122164407A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of environmental remediation application materials technology, specifically relating to a Fe3O4-CuO graphene oxide composite, its preparation method, and its application. Background Technology
[0002] Among water pollution treatment methods, photocatalytic oxidation has the advantages of high efficiency and simple operation. Its oxidation reaction achieves both resource reuse and environmental protection. Photocatalysis generates strong oxidizing or reducing species through light excitation, further decomposing pollutants. This catalytic reaction can fully utilize solar energy to comprehensively degrade organic pollutants, greatly saving the treatment costs of related pollutants and minimizing secondary pollution, making it a relatively ideal wastewater treatment method. However, due to the relatively recent development of photocatalytic oxidation technology, its technical level is not yet fully mature, and it cannot be widely applied to practical wastewater treatment at present. Therefore, further in-depth research is needed, including thorough analysis of the mechanism of visible light catalytic reactions, improving the specificity and reliability of metal-based catalysis, and enabling its better application in environmental remediation. This oxidation reaction, assisted by visible or ultraviolet light, triggers the catalyst to produce active oxide species, which rapidly oxidize various organic pollutants, demonstrating certain applicability. However, the oxidation efficiency of existing catalysts still needs improvement, and the key lies in the development and application of composite catalysts, such as copper oxide and iron oxide, which have advantages such as high activity and selectivity, and recyclability. By improving or combining oxide catalysts, we can make full use of the low-cost and abundant solar energy, which is convenient to use, environmentally friendly, and not prone to secondary pollution.
[0003] Graphene oxide (GO) is a stable carbon nanomaterial with a two-dimensional network structure composed of sp2-hybridized carbon atoms. It has a large specific surface area and exhibits excellent photoelectric properties, mechanical properties, and thermal stability. It can be used as an oxide support to prepare catalysts with better structures and stronger stability. Iron(III) oxide (Fe3O4) is a type of magnetic particle (MP) possessing magnetic and nanoscale properties, as well as certain biocompatibility and surface effects. Combining it with catalysts can yield higher-performance magnetic composite materials with wide applications in environmental remediation and other fields.
[0004] In recent years, antibiotics have emerged as a new type of pollutant in large quantities in my country's river basins and coastal areas, leading to the deterioration of natural water quality and posing a serious crisis to coastal industries such as aquaculture, mining, and salt production. Antibiotics can inhibit or kill specific microorganisms and are widely used in human production and daily life. Based on their chemical structure, they can be classified into tetracyclines, sulfonamides, and quinolones, among others. Studies have found antibiotic residues in seawater, groundwater, and surface water. Large amounts of antibiotics accumulate in water bodies, especially in sediments, posing a very high pollution risk. Tetracycline (TC), a common and representative antibiotic, has been detected in large quantities in the Yangtze River basin. It negatively impacts the microbial community and the abundance of antibiotic resistance genes in the environment. Tetracycline itself is difficult to degrade, easily attaches to other pollutants, and can accumulate in large quantities in the aquatic food chain, harming the growth and development of organisms and forming persistent tetracycline pollution. Summary of the Invention
[0005] This invention aims to overcome the shortcomings of existing photocatalytic catalysts, such as low oxidation efficiency, difficulty in recovery, and insufficient specificity, as well as the problem of the difficulty in degrading tetracycline antibiotic pollutants in water. It provides a Fe3O4-CuO graphene oxide composite with good catalytic activity, high oxidation and recovery efficiency, and good recyclability.
[0006] The technical solution of this invention is as follows: A method for preparing a Fe3O4-CuO graphene oxide composite includes the following steps: (1) Preparation of graphene oxide: Graphite powder was added to concentrated sulfuric acid and stirred thoroughly to disperse it evenly. NaNO3 and KMnO4 were added one after another and magnetic stirring was carried out continuously in an ice-water bath. Then hydrogen peroxide solution was added, and after standing and layering, centrifugation was performed. After separation, the upper clear liquid was discarded, and the precipitate obtained at the bottom was repeatedly washed with deionized water until neutral to obtain graphene oxide. (2) Preparation of CuO composite graphene oxide: CuO was added to glacial acetic acid and stirred evenly to obtain CuO acetic acid solution; the graphene oxide obtained in step (1) was dissolved in ultrapure water and subjected to ultrasonic treatment to obtain graphene oxide dispersion; CuO acetic acid solution was then added to graphene oxide dispersion and ultrasonic reaction was continuously carried out. The reaction product was centrifuged and separated. The precipitate obtained at the bottom was thoroughly dried to obtain CuO composite graphene oxide. (3) Preparation of Fe3O4-CuO graphene oxide composite: FeCl3 and FeCl2 were weighed and dissolved in ultrapure water. After stirring and mixing evenly, an iron salt solution was obtained. CuO composite graphene oxide obtained in step (2) was added to the iron salt solution. The mixture was stirred evenly and heated for a period of time. The reaction product was filtered, washed, and dried to obtain Fe3O4-CuO graphene oxide composite.
[0007] Preferably, in step (1) of the present invention, the ratio of graphite powder to concentrated sulfuric acid is 3g:50-60mL, the ratio of graphite powder to hydrogen peroxide solution is 3g:20-40mL, the volume ratio of deionized water to hydrogen peroxide solution is 5-6:1, and the mass ratio of graphite powder, NaNO3 and KMnO4 is 3:2.5:7.
[0008] Preferably, in step (2) of the present invention, the ratio of CuO to glacial acetic acid is 1-1.5g:100mL, the ratio of graphene oxide to ultrapure water is 0.7:100-120mL, and the volume ratio of CuO acetic acid solution to graphene oxide dispersion is 2:5-6.
[0009] Preferably, in step (3) of the present invention, the mass ratio of FeCl3 to FeCl2 is 42-48:17-19, and the material-liquid ratio of FeCl2 to ultrapure water is 17-19g:50-100mL.
[0010] Preferably, in step (1) of the present invention, the stirring time is 20-30 min and the standing time is 1-1.5 h.
[0011] Preferably, in step (2) of the present invention, the graphene oxide solution is first ultrasonically treated for 0.5-1.0h; after mixing, the ultrasonic reaction is continued for 1.0-3.0h.
[0012] Preferably, in step (3) of the present invention, the stirring is continued for 1.5-2 hours, the reaction temperature in the ultrasonic oscillator is 60-70℃, and the reaction time is 1.5-2.5 hours.
[0013] This invention also provides the Fe3O4-CuO graphene oxide composite prepared by the method of this invention, and provides the application of the Fe3O4-CuO graphene oxide composite in the degradation of tetracycline in water. In application, the concentration of tetracycline in the wastewater is 50-55 mg / L, and 20-30 mg of Fe3O4-CuO graphene oxide composite is added to every 100 mL of tetracycline-contaminated wastewater.
[0014] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows: 1. The Fe3O4-CuO graphene oxide composite of the present invention has high catalytic activity as a catalyst and can significantly improve the degradation efficiency of tetracycline antibiotics.
[0015] 2. The introduction of Fe3O4 into the Fe3O4-CuO graphene oxide composite of the present invention gives the composite good magnetic properties. After the reaction, the catalyst can be recovered through simple magnetic separation, which solves the problem that traditional catalysts are difficult to recover and are prone to secondary pollution.
[0016] 3. The Fe3O4-CuO graphene oxide composite of the present invention has good chemical stability. After five cycles of use, the degradation efficiency is still above 80%, which has high recycling efficiency and reduces processing costs.
[0017] 4. The raw materials used in the preparation process of the Fe3O4-CuO graphene oxide composite of the present invention are inexpensive and abundant, the preparation process is simple and easy to operate, there is no emission of toxic and harmful substances, and the catalyst can be recycled and reused after use, which is not likely to cause secondary pollution, and is in line with the concept of green and environmentally friendly development.
[0018] 5. The Fe3O4-CuO graphene oxide composite of the present invention has strong applicability and can exert a catalytic effect under visible light irradiation. It can make full use of solar energy and is suitable for the degradation treatment of tetracycline pollutants in water bodies (such as coastal waters such as the Beibu Gulf). It can effectively alleviate the harm of antibiotic pollution to coastal industries and the ecological environment and has broad practical application prospects. Attached Figure Description
[0019] Figure 1 The image shows the XRD pattern of the Fe3O4-CuO graphene oxide composite prepared in Example 1.
[0020] Figure 2 The visible absorption spectrum of the Fe3O4-CuO graphene oxide composite prepared in Example 1 is shown.
[0021] Figure 3 The image shows the magnetization curve of the Fe3O4-CuO graphene oxide composite prepared in Example 1.
[0022] Figure 4 The graph shows the degradation efficiency of tetracycline using Fe3O4-CuO graphene oxide as a photocatalyst in Example 4.
[0023] Figure 5 The graph shows the recycling efficiency of Fe3O4-CuO graphene oxide as a photocatalyst in Example 4.
[0024] Figure 6This is a graph showing the adsorption effect of tetracycline on the Fe3O4-CuO graphene oxide composite in Example 5. Detailed Implementation
[0025] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0026] In the following embodiments: The concentration of concentrated sulfuric acid is 98.3 wt.%, and the concentration of hydrogen peroxide solution is 30 wt.%. Example 1
[0027] (1) Preparation of graphene oxide: Weigh 1.50g of graphite powder and add it to 25mL of concentrated sulfuric acid. Place it on a magnetic stirrer and stir for 20min to disperse it evenly. Then add 1.25g of NaNO3 and continue stirring for 10min. Then slowly add 3.50g of KMnO4. Place the mixture in an ice-water bath throughout the process and control the reaction temperature at 5℃. Stir magnetically for 1h. After the reaction is complete, slowly add 60mL of deionized water and stir for 1h. Then slowly add 10mL of hydrogen peroxide and stir for 20min. Let it stand for 1.5h to separate the layers. Place the precipitate in a centrifuge and centrifuge at 8000r / min for 15min. Remove the supernatant. Wash the precipitate at the bottom repeatedly with deionized water and centrifuge until the pH of the supernatant is 7 to obtain graphene oxide. (2) Preparation of CuO graphene oxide composite: Weigh 0.75g CuO and add it to 50mL glacial acetic acid. Stir magnetically for 1h until CuO is completely dissolved to obtain CuO acetic acid solution. Dissolve 0.35g of graphene oxide obtained in step (1) in 50mL ultrapure water and place it in an ultrasonic oscillator. Ultrasonically treat it at 150W power and 30kHz frequency for 30min to obtain graphene oxide dispersion. Slowly add 20mL CuO acetic acid solution to 50mL graphene oxide dispersion and continue ultrasonic reaction for 3h. Wash the obtained reaction product with deionized water 3 times, centrifuge and dry it in a 70℃ hot oven for 8h to obtain CuO composite graphene oxide. (3) Preparation of Fe3O4-CuO graphene oxide composite: Weigh 0.42g FeCl3 and 0.17g FeCl2 and dissolve them in 100mL of ultrapure water. Stir mechanically for 2h until completely dissolved to obtain an iron salt solution. Add 1g of CuO composite graphene oxide obtained in step (2) to the above iron salt solution. Stir continuously for 2h to disperse evenly. Transfer to an ultrasonic oscillator and heat to 60℃. Ultrasonic reaction at 200W power for 1.5h. The obtained reaction product is filtered and separated, washed 3 times with ultrapure water, and dried in a vacuum drying oven at 60℃ for 12h to obtain Fe3O4-CuO graphene oxide composite.
[0028] like Figure 1 As can be seen, characteristic diffraction peaks corresponding to CuO and GO can be found in the spectrum of the prepared Fe3O4-CuO / GO composite, proving the presence of these two phases in the composite. The diffraction peaks at 36.5° and 38.5° belong to the crystal structure of CuO, while the additional diffraction peaks at 29.6˚, 35.3˚, and 43.5˚ are characteristic peaks of Fe3O4. The peaks in the spectrum are complete and there are no obvious impurity peaks, indicating that the obtained sample has high purity. The peak intensity variations in the composite are due to the interaction between Fe3O4 and CuO; the mixed crystal phases affect their respective peaks. This analysis confirms the formation of the Fe3O4-CuO / GO composite.
[0029] Figure 2 The results show that the Fe3O4-CuO / GO composite exhibits an absorption edge at around 450 nm and has a certain absorbance in the visible light region, indicating that it can sufficiently absorb the visible light portion of solar energy. The Fe3O4-CuO / GO composite possesses a wide light absorption region and good visible light conversion capability, enabling it to generate sufficient photoelectrons.
[0030] Figure 3 The prepared Fe3O4-CuO / GO composite exhibits magnetic responsiveness, with a saturation magnetization of 13.5 emu / g. The hysteresis loop in the spectrum confirms that the Fe3O4-CuO / GO composite can exhibit rapid separation under an applied magnetic field. This composite material can serve as an effective magnetic photocatalyst and is easily recyclable. Example 2
[0031] (1) Preparation of graphene oxide: Weigh 1.50g of graphite powder and add it to 25mL of concentrated sulfuric acid. Place it on a magnetic stirrer and stir for 30min to disperse it evenly. Then add 1.25g of NaNO3 and continue stirring for 10min. Then slowly add 3.50g of KMnO4. Place it in an ice-water bath throughout the process and control the reaction temperature at 5℃. Stir magnetically for 30h. After the reaction is completed, slowly add 50mL of deionized water and stir for 1h. Then slowly add 10mL of hydrogen peroxide and stir for 30min. Let it stand for 1h to separate the layers. Place the precipitate in a centrifuge and centrifuge at 8000r / min for 15min. Remove the supernatant. Wash the precipitate obtained at the bottom repeatedly with deionized water and centrifuge until the pH of the supernatant is 7 to obtain graphene oxide. (2) Preparation of CuO graphene oxide composite: Weigh 0.50g CuO and add it to 50mL glacial acetic acid. Stir magnetically for 1h until CuO is completely dissolved to obtain CuO acetic acid solution. Dissolve 0.35g of graphene oxide obtained in step (1) in 50mL ultrapure water and place it in an ultrasonic oscillator. Ultrasonically treat it at 150W power and 30kHz frequency for 30min to obtain graphene oxide dispersion. Slowly add 20mL CuO acetic acid solution to 50mL graphene oxide dispersion and continue ultrasonic reaction for 1.5h. Wash the obtained reaction product with ultrapure water 3 times, centrifuge and dry it in a 70℃ hot oven for 8h to obtain CuO composite graphene oxide. (3) Preparation of Fe3O4-CuO graphene oxide composite: Weigh 0.42g FeCl3 and 0.17g FeCl2 and dissolve them in 50mL of ultrapure water. Stir mechanically for 1.5h until completely dissolved to obtain an iron salt solution. Add 1g of CuO composite graphene oxide obtained in step (2) to the above iron salt solution and stir continuously for 1.5h to disperse evenly. Then transfer it to an ultrasonic oscillator, heat it to 60℃, and ultrasonically react it with 200W power for 2h. After the reaction product is separated by filtration, wash it three times with ultrapure water and dry it in a vacuum drying oven at 60℃ for 12h to obtain Fe3O4-CuO graphene oxide composite. Example 3
[0032] (1) Preparation of graphene oxide: Weigh 1.50g of graphite powder and add it to 30mL of concentrated sulfuric acid. Place it on a magnetic stirrer and stir for 30min to disperse it evenly. Then add 1.25g of NaNO3 and continue stirring for 10min. Then slowly add 3.50g of KMnO4. Place it in an ice-water bath throughout the process and control the reaction temperature at 3℃. Stir magnetically for 1h. After the reaction is completed, slowly add 50mL of deionized water and stir for 1h. Then add 20mL of hydrogen peroxide and stir for 30min. Allow it to stand and separate into layers. Place the precipitate in a centrifuge and centrifuge at 8000r / min for 15min. Remove the supernatant. Wash the precipitate at the bottom repeatedly with deionized water and centrifuge until the pH of the supernatant is 7 to obtain graphene oxide. (2) Preparation of CuO graphene oxide composite: Weigh 0.75g CuO and add it to 50mL glacial acetic acid. Stir magnetically for 1h until CuO is completely dissolved to obtain CuO acetic acid solution. Dissolve 0.35g of graphene oxide obtained in step (1) in 60mL ultrapure water and place it in an ultrasonic oscillator. Ultrasonically treat it at 150W power and 30kHz frequency for 15min to obtain graphene oxide dispersion. Slowly add 20mL CuO acetic acid solution to 60mL graphene oxide dispersion and continue ultrasonic reaction for 1h. Wash the obtained reaction product with ultrapure water 3 times, centrifuge and dry it in a 70℃ hot oven for 8h to obtain CuO composite graphene oxide. (3) Preparation of Fe3O4-CuO graphene oxide composite: Weigh 0.48g FeCl3 and 0.19g FeCl2 and dissolve them in 50mL of ultrapure water. Stir mechanically for 1.5h until completely dissolved to obtain an iron salt solution. Add 1g of CuO composite graphene oxide obtained in step (2) to the above iron salt solution and stir continuously for 1.5h to disperse evenly. Then transfer it to an ultrasonic oscillator, heat it to 70℃, and ultrasonically react it at 150W power for 2.5h. The reaction product obtained is filtered and separated, washed 3 times with ultrapure water, and dried in a vacuum drying oven at 60℃ for 12h to obtain Fe3O4-CuO graphene oxide composite.
[0033] Example 4: Application of the Fe3O4-CuO graphene oxide composite prepared in Example 1 in the degradation of tetracycline. (1) Measure 100 mL of tetracycline TC solution with a concentration of 50 mg / L and transfer it into a quartz test tube. Add 20 mg of Fe3O4-CuO graphene oxide composite and mix well. Place the test tube in a photochemical reactor and turn on the xenon lamp as the reaction light source. Take a sample of the dispersion every 10 min under the light and filter it to obtain the sample to be tested. (2) The absorbance of the tetracycline solution was measured by a UV-Vis spectrophotometer to determine the remaining concentration of tetracycline; (3) Repeat steps (1) and (2), and use a magnet to separate and recover the composite catalyst after the light reaction. After drying it thoroughly under vacuum, it can be reused in the experiment. Repeat the same experimental conditions 5 times.
[0034] To verify the application effect of Fe3O4-CuO graphene oxide composite in degrading tetracycline in wastewater, the following comparative examples were set up: (1) Unlike Example 4, Fe3O4-CuO graphene oxide composite was replaced with CuO as catalyst, and the rest was the same as Example 4; (2) Unlike Example 4, no catalyst was used (i.e. no Fe3O4-CuO graphene oxide composite was used), and the rest was the same as Example 4.
[0035] The experimental results are shown in Figure 4 As shown, with the catalytic effect of Fe3O4-CuO graphene oxide, the concentration of tetracycline (TC) gradually decreased. When the initial TC concentration was 50 mg / L, the degradation efficiency of TC by the composite catalyst reached 80.2% after 60 min of visible light irradiation. In comparison, the degradation efficiencies of pure CuO and pure light irradiation for TC were 35.3% and 4.9%, respectively. It can be seen that the photocatalytic performance of the Fe3O4-CuO / GO composite is significantly improved compared to metal oxides, which has considerable practical significance for wastewater treatment in production processes.
[0036] Figure 5 The results demonstrate the reusability of the composite catalyst, indicating that the degradation efficiency of Fe3O4-CuO / GO for antibiotics remained at a high level after multiple repeated experiments, with an overall decrease of less than 7.5%. The composite maintained good photoreactivity, and its catalytic ability remained essentially unchanged.
[0037] Example 5: Adsorption of tetracycline by the Fe3O4-CuO graphene oxide composite prepared in Example 1 Measure 100 mL of tetracycline solution (concentration 50 mg / L), add 20 mg of Fe3O4-CuO graphene oxide composite, and continuously stir the dispersion under light-free conditions to carry out the adsorption reaction. Take samples of the dispersion every 10 min, and place the filtered samples into a UV-Vis spectrophotometer to determine the concentration.
[0038] Meanwhile, the following comparative examples were set up: (1) The difference from Example 5 is that the Fe3O4-CuO graphene oxide composite was replaced with CuO, and the rest was the same as in Example 5; (2) The difference from Example 5 is that the Fe3O4-CuO graphene oxide composite was replaced with graphene oxide, and the rest was the same as in Example 5.
[0039] Depend on Figure 6The trend shows that under no-light conditions, the adsorption efficiency of Fe3O4-CuO / GO for tetracycline TC is 21.6%, while the adsorption efficiency of pure GO is 28.1%. The decrease in the composite catalyst's efficiency is partly due to the addition of CuO and Fe3O4 particles occupying some of the active sites on the GO surface. However, the presence of CuO significantly enhances the photocatalytic activity of the composite material, and Fe3O4 imparts good magnetic responsiveness to the material.
[0040] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit of the present invention should fall within the patent scope covered by the present invention.
Claims
1. A method for preparing a Fe3O4-CuO graphene oxide composite, characterized in that, Includes the following steps: (1) Preparation of graphene oxide: Graphite powder was added to concentrated sulfuric acid and stirred thoroughly to disperse it evenly. NaNO3 and KMnO4 were added one after another and magnetic stirring was carried out continuously in an ice-water bath. Then deionized water and hydrogen peroxide solution were added. After standing and separating into layers, centrifugation was performed. After separation, the supernatant was discarded and the precipitate obtained at the bottom was repeatedly washed with deionized water until neutral to obtain graphene oxide. (2) Preparation of CuO composite graphene oxide: CuO was added to glacial acetic acid and stirred evenly to obtain CuO acetic acid solution; the graphene oxide obtained in step (1) was dissolved in ultrapure water and subjected to ultrasonic treatment to obtain graphene oxide dispersion; CuO acetic acid solution was then added to graphene oxide dispersion and ultrasonic reaction was continuously carried out. The reaction product was centrifuged and separated, and the precipitate obtained at the bottom was thoroughly dried to obtain CuO composite graphene oxide. (3) Preparation of Fe3O4-CuO graphene oxide composite: FeCl3 and FeCl2 were weighed and dissolved in ultrapure water. After stirring and mixing evenly, an iron salt solution was obtained. CuO composite graphene oxide obtained in step (2) was added to the iron salt solution. The mixture was stirred evenly and heated for a period of time. The reaction product was filtered, washed, and dried to obtain Fe3O4-CuO graphene oxide composite.
2. The preparation method of the Fe3O4-CuO graphene oxide composite as described in claim 1, characterized in that: In step (1), the ratio of graphite powder to concentrated sulfuric acid is 3g:50-60mL, the ratio of graphite powder to hydrogen peroxide solution is 3g:20-40mL, the volume ratio of deionized water to hydrogen peroxide solution is 5-6:1, and the mass ratio of graphite powder, NaNO3 and KMnO4 is 3:2.5:
7.
3. The preparation method of the Fe3O4-CuO graphene oxide composite as described in claim 1, characterized in that: In step (2), the ratio of CuO to glacial acetic acid is 1-1.5g:100mL, the ratio of graphene oxide to ultrapure water is 0.7:100-120mL, and the volume ratio of CuO acetic acid solution to graphene oxide dispersion is 2:5-6.
4. The preparation method of the Fe3O4-CuO graphene oxide composite as described in claim 1, characterized in that: In step (3), the mass ratio of FeCl3 to FeCl2 is 42-48:17-19, and the ratio of FeCl2 to ultrapure water is 17-19g:50-100mL.
5. The method for preparing the Fe3O4-CuO graphene oxide composite as described in claim 1, characterized in that: In step (1), the stirring time is 20-30 min and the standing time is 1-1.5 h.
6. The method for preparing the Fe3O4-CuO graphene oxide composite as described in claim 1, characterized in that: In step (2), the graphene oxide solution is first ultrasonically treated for 0.5-1.0h; after mixing, the ultrasonic reaction is continued for 1.0-3.0h.
7. The method for preparing the Fe3O4-CuO graphene oxide composite as described in claim 1, characterized in that: In step (3), the stirring is continued for 1.5-2 hours, the reaction temperature in the ultrasonic oscillator is 60-70℃, and the reaction time is 1.5-2.5 hours.
8. The Fe3O4-CuO graphene oxide composite prepared by the method according to any one of claims 1-7.
9. The application of the Fe3O4-CuO graphene oxide composite as described in claim 8 in the degradation of tetracycline in water.
10. The application as described in claim 9, characterized in that: The concentration of tetracycline in the wastewater is 50-55 mg / L, and 20-30 mg of Fe3O4-CuO graphene oxide complex is added to every 100 mL of tetracycline wastewater.