A CoCuFe2O4@GO ternary composite material, its preparation method and application

Abstract

The application provides a CoCuFe2O4@GO ternary composite material and a preparation method and application thereof, and relates to the field of environmental functional materials. The preparation method of the ternary composite material is as follows: a Co / CuFe2O4 nano powder and graphene oxide are combined through an interface chemical bond to form the material, wherein cobalt elements enter a CuFe2O4 crystal lattice in a doped form; the method comprises the following steps: S1, mixing a copper source, an iron source and a cobalt source with water to prepare a mixed metal salt solution, adding citric acid into the mixed metal salt solution, and preparing the Co / CuFe2O4 nano powder through a sol-gel combustion method; S2, mixing the Co / CuFe2O4 nano powder with a graphene oxide dispersion solution, and preparing the Co / CuFe2O4@GO ternary composite material through a hydrothermal method. In the application, the synergistic process of the sol-gel combustion method and the hydrothermal method ensures uniform doping of cobalt and stable loading of GO, and the obtained material has a high specific surface area and excellent magnetism. The material can efficiently activate hydrogen peroxide to degrade organic pollutants under visible light irradiation, and is especially suitable for antibiotic wastewater treatment.

Description

Technical Field

[0001] This invention relates to the field of environmental functional materials, and in particular to a cobalt / copper ferrite-supported graphene (Co / CuFe2O4@GO) ternary composite material and its preparation method, as well as the application of this material in degrading antibiotics such as oxytetracycline (OTC) in water. Background Technology

[0002] Traditional Fenton technology, as a classic advanced oxidation process, has been widely used in the treatment of organic wastewater. This technology relies on Fe... 2+ Catalytic decomposition of H₂O₂ to generate hydroxyl radicals (·OH) for pollutant degradation, while possessing strong oxidizing power, its practical application is severely limited. The reaction must be carried out under strongly acidic conditions (pH 2-4), which necessitates the consumption of large amounts of acid and alkali reagents to adjust the pH value during actual wastewater treatment. More seriously, the reaction generates a large amount of iron-containing sludge, causing secondary pollution and significantly increasing subsequent treatment costs. Furthermore, dissolved Fe... 2+ The catalyst cannot be recycled, leading to resource waste and increased operating costs.

[0003] To overcome the limitations of traditional Fenton technology, researchers have developed heterogeneous Fenton catalytic systems, among which spinel-type copper ferrite (CuFe2O4) has attracted much attention due to its unique structural properties. These materials remain stable over a wide pH range (3-9) and exhibit ferromagnetism, facilitating magnetic separation and recovery. CuFe2O4 contains Cu... 2+ / Cu + and Fe 3+ / Fe 2+ Theoretically, a redox pair can synergistically activate H₂O₂. However, CuFe₂O₄ catalysts prepared by traditional co-precipitation methods often have small specific surface areas (<50 m²). 2 Problems include insufficient exposure of active sites (e.g.). Its semiconductor properties result in a high recombination rate of photogenerated carriers, limiting the activation efficiency of H2O2. In addition, its wide band gap (>2.0 eV) makes it primarily respond to ultraviolet light, with low utilization of visible light.

[0004] In recent years, graphene-based composite materials have provided new insights into improving Fenton catalysis performance. Graphene oxide (GO) possesses an ultra-high specific surface area (theoretical value 2630 m² / g) and excellent electrical conductivity (~10). 6The graphene-based Fenton catalyst (S / m) effectively disperses the active components and promotes electron transfer. Its abundant oxygen-containing functional groups (-COOH, -OH, etc.) facilitate strong interactions with metal oxides. While the CuFe2O4 / rGO composite material disclosed in existing patents improves catalytic performance to some extent, the co-precipitation method results in uneven dispersion of the active components and weak metal-support interface bonding. Another patent reports a CoFe2O4 / GO catalyst with improved activity, but cobalt species are prone to aggregation, leading to insufficient cycle stability, and the preparation process is relatively complex. These technical defects severely limit the practical application of graphene-based Fenton catalysts.

[0005] Furthermore, although graphene-based materials with cobalt as the active center (such as certain systems that activate persulfate) perform well in degrading antibiotics, persulfate itself is expensive and may leave sulfate residues after the reaction. Hydrogen peroxide (H2O2), as a green oxidant, is inexpensive and its decomposition product is only water, making it a more ideal choice. However, H2O2 has a high O / O bond energy, making it difficult to activate efficiently under neutral conditions. Therefore, how to combine the advantages of cobalt doping modification with graphene composites to develop a novel catalyst that can efficiently, stably, and selectively activate low-concentration H2O2 under neutral conditions has become a pressing technical bottleneck that needs to be overcome, and it has greater practical application value. Summary of the Invention

[0006] This invention addresses the technical bottlenecks of existing Fenton catalysts, such as insufficient activity, poor stability, and narrow photoresponse range, by providing a novel Co / CuFe2O4@GO ternary composite photo-Fenton material and its preparation method. Through unique structural design and preparation process, this material achieves a significant improvement in catalytic performance.

[0007] The technical solution of this invention is implemented as follows: A method for preparing a Co / CuFe2O4@GO ternary composite material, wherein the material is composed of Co / CuFe2O4 nanopowder and graphene oxide through interfacial chemical bonds, wherein cobalt is incorporated into the CuFe2O4 lattice in a doping form; the method includes the following steps: S1. Mix copper source, iron source and cobalt source with water to prepare a mixed metal salt solution. Add citric acid to the mixed metal salt solution and obtain Co / CuFe2O4 nanopowder by sol-gel combustion method. S2. Co / CuFe2O4 nanoparticles were mixed with graphene oxide dispersion, and Co / CuFe2O4@GO ternary composite material was prepared by hydrothermal method.

[0008] Furthermore, in step S1, the copper source and the iron source are in a molar ratio of Cu:Fe = 1:1.9-2.1; the molar amount of Co in the cobalt source is 5%-15% of the total molar amount of Cu and Fe in the copper source and the iron source, preferably 10%-15%, and more preferably 13%.

[0009] Furthermore, the copper source is at least one of Cu(NO3)2·3H2O, CuCl2·2H2O, and CuSO4·5H2O; The iron source is at least one of Fe(NO3)3·9H2O, FeCl3·6H2O, and Fe2(SO4)3; The cobalt source is at least one of Co(NO3)2·6H2O, CoCl2·6H2O, and CoSO4·7H2O.

[0010] Furthermore, in step S1, the preparation method of the Co / CuFe2O4 binary nanomaterial includes the following steps: (1) Mix copper, iron and cobalt sources with water to prepare a mixed metal salt solution; (2) Add citric acid to the mixed metal salt solution in step (1), and then adjust the pH to neutral; stir at a constant temperature of 85-95℃ to form a wet gel; (3) Dry the wet gel from step (2) to form a dry gel; ignite the dry gel to obtain a black fork-shaped substance, and then anneal it to obtain Co-doped CuFe2O4 nanopowder, i.e., obtain Co / CuFe2O4 nanopowder.

[0011] Furthermore, in step S1, the preparation method of the Co / CuFe2O4 binary nanomaterial includes the following steps: (1) Dissolve copper, iron and cobalt sources in water to prepare a mixed metal salt solution; (2) Add citric acid to the mixed metal salt solution obtained in step (1). The molar ratio of metal ions to citric acid in the mixed metal salt solution is 0.9-1.1:0.9-1.1. Then adjust the pH to neutral. Stir at a constant temperature of 85-95℃ for 4-5 hours to form a wet gel. (3) Transfer the wet gel obtained in step (2) to an oven at 125-135℃ and dry it for 4-6 hours to form a dry gel; ignite the dry gel to obtain a black fork-shaped object, and then place it in a muffle furnace and anneal it at 450-550℃ for 2-4 hours to obtain Co-doped CuFe2O4 nanopowder, i.e., obtain Co / CuFe2O4 nanopowder.

[0012] Furthermore, in step S2, the mass ratio of the Co / CuFe2O4 nanoparticles to graphene oxide is 1:0.5-2.

[0013] Furthermore, in step S2, the preparation method of the Co / CuFe2O4@GO ternary composite material includes the following steps: (1) Mix graphene oxide with water to obtain a uniform graphene oxide dispersion; (2) Co / CuFe2O4 nanopowder was mixed with anhydrous ethanol to obtain a uniform Co / CuFe2O4 dispersion; (3) Mix the graphene oxide dispersion and the Co / CuFe2O4 dispersion, stir, and perform hydrothermal reaction. After centrifugation and washing, the reaction product is dried under vacuum to finally obtain the Co / CuFe2O4@GO ternary composite material.

[0014] Furthermore, in step S2, the preparation method of the Co / CuFe2O4@GO ternary composite material includes the following steps: (1) Disperse graphene oxide in water and sonicate for 0.5-1.5 hours to obtain graphene oxide dispersion; (2) Disperse Co / CuFe2O4 nanoparticles in anhydrous ethanol and sonicate for 20-40 min to form a Co / CuFe2O4 dispersion; (3) The graphene oxide dispersion and the Co / CuFe2O4 dispersion were mixed at a mass ratio of 1:0.5-2. After stirring for 20-40 minutes, the mixture was transferred to a reaction vessel lined with polyethylene tetroxide. The mixture was then subjected to hydrothermal reaction at 175-185℃ for 10-14 hours. After centrifugation and washing, the reaction product was vacuum dried at 55-65℃ for 20-30 hours to finally obtain the Co / CuFe2O4@GO ternary composite material.

[0015] A Co / CuFe2O4@GO ternary composite material is prepared by any one of the preparation methods described in this invention.

[0016] The present invention relates to the application of the Co / CuFe2O4@GO ternary composite material in the photo-Fenton degradation of oxytetracycline.

[0017] Furthermore, the specific steps for using the Co / CuFe2O4@GO ternary composite material for photo-Fenton degradation of oxytetracycline are as follows: (1) 10 mg of Co / CuFe2O4@GO ternary composite material (catalyst) and 200 mL of oxytetracycline solution (initial concentration 10 mg / L) were added to a 250 mL reactor and the adsorption experiment was carried out in the dark at 25℃. 1 mL of sample was taken every 10 minutes (no liquid was added after sampling) and the OTC (oxytetracycline) concentration was determined by UV-2500 spectrometer until adsorption equilibrium was reached. (2) Irradiate the suspension under visible light conditions, and add the required amount of H2O2 to the above mixed solution to initiate the photo-Fenton catalytic reaction; at a given interval, take 5 ml of sample from the reactor and analyze the absorbance at a specified wavelength using a UV 2500 spectrophotometer. (3) The effects of adjusting the H2O2 concentration (0.1 mmol-6 mmol) and initial pH (3-11) on the degradation reaction were investigated. (4) After the reaction, the used catalyst is collected again, washed several times with water and ethanol, and dried at 60°C for recycling test.

[0018] Furthermore, the Co / CuFe2O4@GO ternary composite material of the present invention exhibits excellent photocatalytic activity when used to activate low-concentration H2O2 to degrade oxytetracycline in water.

[0019] Compared with the prior art, the beneficial effects of the present invention are: Unlike existing one-step composite processes using co-precipitation, this invention creatively employs a step-by-step synergistic preparation strategy combining the "sol-gel combustion method" and the "hydrothermal method." First, a Co / CuFe2O4 precursor with high crystallinity, a well-defined spinel structure, and uniform cobalt doping within the crystal lattice is precisely prepared through high-temperature calcination using the sol-gel combustion method. This step ensures that cobalt forms a stable Co-O-Fe bond structure through lattice substitution, rather than simply being a surface load, thus allowing the original Cu atoms in CuFe2O4 to... 2+ / Cu + and Fe 3+ / Fe 2+ Based on the redox pair, add Co 2+ / Co 3+ Redox pairs. The three pairs of multivalent metal cycles generate a synergistic effect through electron transfer within the crystal lattice, significantly improving the activation efficiency of H2O2. At the same time, cobalt doping can adjust the band structure of the material, enhance the visible light response, and achieve efficient coupling of photocatalysis and Fenton-like reaction, a characteristic not possessed by traditional catalysts with Fe3O4 or MnO2 as the core.

[0020] Subsequently, Co / CuFe2O4 nanosheets were firmly anchored onto graphene oxide sheets using a mild hydrothermal method. Graphene oxide, acting as a conductive carrier, not only increased the specific surface area of ​​the material but also promoted the separation of photogenerated electron-hole pairs. This stepwise strategy effectively avoided the interference of GO on the metal ion crystallization process in the co-precipitation method, achieving a balance between the integrity of the active component's crystal structure and the high dispersibility of the carrier, laying the foundation for constructing heterostructures with strong interfacial coupling.

[0021] Based on the above methods and structural design, the CoCuFe2O4@GO composite material prepared by this invention exhibits significant advantages in degrading organic pollutants: it maintains high catalytic activity within a pH range of 3-9, eliminating the need to adjust the wastewater pH; its utilization rate of H2O2 exceeds 85%, far surpassing that of traditional Fenton catalysts; and the material possesses magnetic and recyclable properties, maintaining an activity of over 98% after five cycles. Therefore, this invention offers advantages such as low operating costs, excellent environmental compatibility, and minimal risk of anion residue, making it more suitable for large-scale water treatment applications. Attached Figure Description

[0022] Figure 1 The image shows the powder X-ray diffraction (XRD) pattern of the material obtained in Example 1; in the image, Intensity represents the intensity.

[0023] Figure 2 The images shown are scanning electron microscope (SEM) images of the Co / CFO@GO ternary composite material obtained in Example 1, the Co / CFO binary material obtained in Comparative Example 1, and graphene oxide. Figure 2 a: 13% Co / CFO binary material; Figure 2 b: Single graphene oxide (GO); Figure 2 c: The Co / CuFe2O4@GO ternary composite material obtained in Example 1.

[0024] Figure 3 The image shows the Fourier transform infrared spectrum (FT-IR) of the material obtained in Example 1; in the image, Wavenumber and Transminttance are the transmittance values.

[0025] Figure 4 The X-ray photoelectron spectroscopy (XPS) of the Co / CFO@GO and Co / CFO binary composite materials obtained in Example 1 is shown in the figure. In the figure, Intensity: intensity; Binding energy: binding energy.

[0026] Figure 5 The OTC degradation performance of different Co / CFO@GO ternary composites and Co / CFO binary composites was studied.

[0027] Figure 6 The OTC degradation performance of Co / CFO@GO (2:1) ternary composite material and Co / CFO binary composite material after 1-5 cycles of use.

[0028] Figure 7 The EPR spectrum of the material Co / CFO@GO obtained in Example 1 is shown; in the figure, Magnetic field (G) represents the magnetic field.

[0029] Figure 8The H2O2 consumption kinetics test of the Co / CFO@GO material obtained in Example 1 is shown. Remaining H2O2: concentration of remaining H2O2; Time: time.

[0030] Figure 9 To demonstrate the OTC degradation performance under different pH conditions in Example 1.

[0031] Figure 10 To demonstrate the OTC degradation performance under different H2O2 concentrations in Example 2. Detailed Implementation

[0032] Unless otherwise specified, the experimental methods used in the embodiments of this invention are conventional methods; Unless otherwise specified, all materials and reagents used in the embodiments of this invention are commercially available.

[0033] The Chinese meanings of some abbreviations or English terms in this invention are as follows: GO: Graphene oxide; OTC: Oxytetracycline.

[0034] Example 1 Step 1, Synthesis of Co / CuFe2O4 (Co / CFO) nanomaterials: (1) Weigh 10 mmol Cu(NO3)2·3H2O and 20 mmol Fe(NO3)3·9H2O, and 3.9 mmol Co(NO3)2·6H2O respectively and dissolve them in 30 ml of deionized water to prepare a mixed metal salt solution; (2) Weigh 33.9 mmol of citric acid and dissolve it in the above mixed metal salt solution, and then adjust the pH to neutral with ammonia. (3) Stir in a water bath at 90℃ for 4~5h until a wet gel is formed, and then dry in an oven at 130℃ for 5h to form a dry gel; ignite the dry gel to obtain a black fork-shaped object, and then place it in a muffle furnace and anneal at 500℃ for 3h to obtain Co-doped CuFe2O4 (Co / CuFe2O4) powder.

[0035] Step 2, Synthesis of Co / CuFe2O4@GO (Co / CFO@GO 2:1) ternary composite material: (1) Pretreatment of graphene oxide: 0.1g GO is dispersed in an appropriate amount of deionized water and ultrasonically treated for 1 hour to form a uniform dispersion.

[0036] (2) Disperse 0.2g Co / CuFe2O4 powder in anhydrous ethanol and sonicate for 30min to form a uniform dispersion.

[0037] (3) The uniform dispersions obtained in (1) and (2) above were mixed (the mass ratio of GO to Co / CuFe2O4 was 1:2), stirred for 30 minutes, and then transferred to a reaction vessel lined with polyethylene tetroxide. The reaction was carried out hydrothermally at 180°C for 12 hours. After centrifugation and washing, the reaction product was dried under vacuum at 60°C for 24 hours to finally obtain the Co / CuFe2O4@GO ternary composite material.

[0038] Example 2 Step 1, Synthesis of Co / CuFe2O4 (Co / CFO) nanomaterials: (1) Weigh 10 mmol Cu(NO3)2·3H2O and 20 mmol Fe(NO3)3·9H2O, and 3.9 mmol Co(NO3)2·6H2O respectively and dissolve them in 30 ml of deionized water to prepare a mixed metal salt solution; (2) Weigh 33.9 mmol of citric acid and dissolve it in the above mixed metal salt solution, and then adjust the pH to neutral with ammonia. (3) Stir in a water bath at 90℃ for 4~5h until a wet gel is formed, and then dry in an oven at 130℃ for 5h to form a dry gel. Ignite the dry gel to obtain a black fork-shaped object, and then place it in a muffle furnace and anneal at 500℃ for 3h to obtain Co-doped CuFe2O4 (Co / CuFe2O4) powder.

[0039] Step 2, Synthesis of Co / CuFe2O4@GO (Co / CFO@GO 1:1) ternary composite material: (4) Pretreatment of graphene oxide: 0.1g GO is dispersed in an appropriate amount of deionized water and ultrasonically treated for 1 hour to form a uniform dispersion.

[0040] (5) Disperse 0.1g Co / CuFe2O4 powder in anhydrous ethanol and sonicate for 30min to form a uniform dispersion.

[0041] (6) The uniform dispersions obtained in (1) and (2) above were mixed (the mass ratio of GO to Co / CuFe2O4 was 1:1), stirred for 30 minutes, and then transferred to a reaction vessel lined with polyethylene tetroxide. The reaction was carried out hydrothermally at 180°C for 12 hours. After centrifugation and washing, the reaction product was dried under vacuum at 60°C for 24 hours to finally obtain the Co / CuFe2O4@GO ternary composite material.

[0042] Example 3 Step 1, Synthesis of Co / CuFe2O4 (Co / CFO) nanomaterials: (1) Weigh 10 mmol Cu(NO3)2·3H2O and 20 mmol Fe(NO3)3·9H2O, and 3.9 mmol Co(NO3)2·6H2O respectively and dissolve them in 30 ml of deionized water to prepare a mixed metal salt solution; (2) Weigh 33.9 mmol of citric acid and dissolve it in the above mixed metal salt solution, and then adjust the pH to neutral with ammonia. (3) Stir in a water bath at 90℃ for 4~5h until a wet gel is formed, and then dry in an oven at 130℃ for 5h to form a dry gel. Ignite the dry gel to obtain a black fork-shaped object, and then place it in a muffle furnace and anneal at 500℃ for 3h to obtain Co-doped CuFe2O4 (Co / CuFe2O4) powder.

[0043] Step 2, Synthesis of Co / CuFe2O4@GO (Co / CFO@GO 1:2) ternary composite material: (1) Pretreatment of graphene oxide: 0.2g GO is dispersed in an appropriate amount of deionized water and ultrasonically treated for 1 hour to form a uniform dispersion.

[0044] (2) Disperse 0.1g Co / CuFe2O4 powder in anhydrous ethanol and sonicate for 30min to form a uniform dispersion.

[0045] (3) The uniformly dispersed liquids obtained in (1) and (2) above were mixed (the mass ratio of GO to Co / CuFe2O4 was 2:1), stirred for 30 minutes, and then transferred to a reaction vessel with a polyethylene tetroxide liner. The reaction was carried out hydrothermally at 180°C for 12 hours. After centrifugation and washing, the reaction product was vacuum dried at 60°C for 24 hours to finally obtain the Co / CuFe2O4@GO ternary composite material.

[0046] Comparative Example 1 The main difference between Comparative Example 1 and Example 1 is the absence of graphene oxide (GO). Following step 1 of Example 1, Co / CuFe2O4 nanomaterials were prepared, resulting in a Co / CFO binary composite material (the molar amount of Co in the cobalt source was 13% of the total molar amount of Cu and Fe in the copper and iron sources, denoted as 13% Co doping). Experimental results show that under the same reaction conditions, the degradation rates of Comparative Example 1 and Example 1 were 88% and 98.9% respectively after 90 minutes, and remained at 87.5% and 98.7% respectively after 5 cycles. The Co / CFO@GO ternary composite material of Example 1 exhibits superior performance and a more stable structure compared to the Co / CFO binary composite material of Comparative Example 1. The corresponding comparative results are as follows: Figure 5 and Figure 6 As shown.

[0047] The materials obtained in the above embodiments were characterized and tested. Example 1 is a typical example, and the characterization results are described below: The powder X-ray diffraction (XRD) pattern of the material obtained in Example 1 is as follows: Figure 1 As shown, by Figure 1 As can be seen from the XRD patterns of GO, Co / CFO, Co / CFO@GO(1:1), Co / CFO@GO(1:2), and Co / CFO@GO(2:1), the three clearly defined diffraction peaks of Co / CFO appear at 30.2°, 35.6°, and 43.3°, corresponding to the (220), (311), and (400) crystal planes of standard spinel CuFe2O4, respectively. For GO, the sharp characteristic peak appears at 11.1°, corresponding to the (001) crystal plane between GO layers. In the pattern of Co / CFO@GO, characteristic diffraction peaks corresponding to Co / CFO can still be observed. At the same time, as the Co / CFO content increases, the characteristic peaks of GO relatively weaken. The position and intensity of these peaks indicate that the composite material was successfully synthesized.

[0048] Scanning electron microscope (SEM) images of the Co / CFO@GO obtained in Example 1 and the materials obtained in Comparative Example 1 are shown below. Figure 2 As shown, by Figure 2 c shows that Co / CFO@GO has a sheet-like structure.

[0049] The Fourier transform infrared spectrum (FT-IR) of the material obtained in Example 1 is as follows: Figure 3 As shown, by Figure 3 It can be seen that at 520cm -1 350cm -1 Left and right sides and 1600cm -1 The peaks at the specified locations are attributed to the stretching vibrations of the Fe-O and Cu-O bonds in Co / CFO and the C=C bond in GO, respectively, indicating the successful synthesis of the Co / CFO@GO ternary composite material. To elucidate the high efficiency of the Co / CFO@GO (2:1) catalyst obtained in Example 1, a series of in-depth characterizations were performed.

[0050] XPS analysis results are as follows: Figure 4 As shown, its Fe 2+ The proportion is as high as 65.21%, and there is a clear MOC bond characteristic peak at 530.9 eV in the O1s spectrum, indicating that a strong interfacial chemical coupling is formed between Co / CFO and GO, and provides abundant low-valence metal active sites.

[0051] Significant TEMPO-h was observed in the EPR test. + DMPO-·O2 - DMPO-·OH characteristic peak signal (such as Figure 7This directly confirms the existence of h within the system. + O2 - The efficient generation of ·OH. Meanwhile, H2O2 consumption kinetics tests show (e.g.) Figure 8 Under optimal conditions, the conversion rate of H2O2 reached over 85% within 90 minutes of reaction, demonstrating the catalyst's efficient activation and utilization of H2O2, rather than ineffective decomposition. These results collectively reveal that the Co-Cu-Fe multimetallic synergistic catalytic cycle, the rapid interfacial electron transfer channel constructed by MOC bonds, and the efficient activation capability for H2O2 are the key mechanisms by which this catalyst achieves excellent degradation performance under neutral conditions.

[0052] Example 4 Based on Example 1 (where the molar amount of Co in the cobalt source is 13% of the total molar amount of Cu and Fe in the copper and iron sources, denoted as 13% Co doping), the Co doping amount was adjusted to 5%, 7%, 10%, and 15%, respectively. The resulting Co / CFO nanomaterials were all significantly superior to undoped CFO. The objective of this invention can be achieved when the molar amount of Co in the cobalt source is 5%, 7%, 10%, or 15% of the total molar amount of Cu and Fe in the copper and iron sources.

[0053] Application Example 1 Application Example 1 and Example 1 used the same catalyst. The main difference was that the OTC degradation performance was examined under different pH conditions. The performance comparison results are as follows: Figure 9 As shown.

[0054] Application Example 2 Application Example 2 uses the same catalyst as Example 1. The main difference is that the OTC degradation performance was investigated under different concentrations of H2O2. The performance comparison results are as follows: Figure 10 As shown.

[0055] The results above show that, compared to single GO and Co / CFO binary nanocomposites, the Co / CFO@GO ternary composites prepared in Examples 1-3 of this invention achieve a higher OTC removal rate at neutral pH. Therefore, the Co / CFO@GO ternary composites prepared by the method of this invention have advantages such as simple operation, low cost, and high efficiency.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the scope of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a Co / CuFe2O4@GO ternary composite material, characterized in that, The material is composed of Co / CuFe2O4 nanopowder and graphene oxide through interfacial chemical bonds, wherein cobalt is incorporated into the CuFe2O4 lattice in the form of dopant. Includes the following steps: S1. Mix copper source, iron source and cobalt source with water to prepare a mixed metal salt solution. Add citric acid to the mixed metal salt solution and obtain Co / CuFe2O4 nanopowder by sol-gel combustion method. S2. Co / CuFe2O4 nanoparticles were mixed with graphene oxide dispersion, and Co / CuFe2O4@GO ternary composite material was prepared by hydrothermal method.

2. The preparation method of the Co / CuFe2O4@GO ternary composite material according to claim 1, characterized in that, In step S1, the copper source and the iron source are in a molar ratio of Cu:Fe = 1:1.9-2.1; the molar amount of Co in the cobalt source is 5%-15% of the total molar amount of Cu and Fe in the copper source and the iron source.

3. The preparation method of the Co / CuFe2O4@GO ternary composite material according to claim 1, characterized in that, The copper source is at least one of Cu(NO3)2·3H2O, CuCl2·2H2O, and CuSO4·5H2O; The iron source is at least one of Fe(NO3)3·9H2O, FeCl3·6H2O, and Fe2(SO4)3; The cobalt source is at least one of Co(NO3)2·6H2O, CoCl2·6H2O, and CoSO4·7H2O.

4. The method for preparing the Co / CuFe2O4@GO ternary composite material according to any one of claims 1-3, characterized in that, In step S1, the preparation method of the Co / CuFe2O4 binary nanomaterial includes the following steps: (1) Mix copper, iron and cobalt sources with water to prepare a mixed metal salt solution; (2) Add citric acid to the mixed metal salt solution in step (1), and then adjust the pH to neutral; stir at a constant temperature of 85-95℃ to form a wet gel; (3) Dry the wet gel from step (2) to form a dry gel; ignite the dry gel to obtain a black fork-shaped substance, and then anneal it to obtain Co-doped CuFe2O4 nanopowder, i.e., obtain Co / CuFe2O4 nanopowder.

5. The preparation method of the Co / CuFe2O4@GO ternary composite material according to claim 4, characterized in that, In step S1, the preparation method of the Co / CuFe2O4 binary nanomaterial includes the following steps: (1) Dissolve copper, iron and cobalt sources in water to prepare a mixed metal salt solution; (2) Add citric acid to the mixed metal salt solution obtained in step (1). The molar ratio of metal ions to citric acid in the mixed metal salt solution is 0.9-1.1:0.9-1.

1. Then adjust the pH to neutral. Stir at a constant temperature of 85-95℃ for 4-5 hours to form a wet gel. (3) Transfer the wet gel obtained in step (2) to an oven at 125-135℃ and dry it for 4-6 hours to form a dry gel; ignite the dry gel to obtain a black fork-shaped object, and then place it in a muffle furnace and anneal it at 450-550℃ for 2-4 hours to obtain Co-doped CuFe2O4 nanopowder, i.e., obtain Co / CuFe2O4 nanopowder.

6. The preparation method of the Co / CuFe2O4@GO ternary composite material according to claim 1, characterized in that, In step S2, the mass ratio of the Co / CuFe2O4 nanopowder to graphene oxide is 1:0.5-2.

7. The method for preparing the Co / CuFe2O4@GO ternary composite material according to claim 1 or 6, characterized in that, In step S2, the preparation method of the Co / CuFe2O4@GO ternary composite material includes the following steps: (1) Mix graphene oxide with water to obtain a graphene oxide dispersion; (2) Co / CuFe2O4 nanoparticles were mixed with anhydrous ethanol to obtain a Co / CuFe2O4 dispersion; (3) Mix the graphene oxide dispersion and the Co / CuFe2O4 dispersion, stir, and perform hydrothermal reaction. After centrifugation and washing, the reaction product is dried under vacuum to finally obtain the Co / CuFe2O4@GO ternary composite material.

8. The preparation method of the Co / CuFe2O4@GO ternary composite material according to claim 7, characterized in that, In step S2, the preparation method of the Co / CuFe2O4@GO ternary composite material includes the following steps: (1) Disperse graphene oxide in water and sonicate for 0.5-1.5 hours to obtain graphene oxide dispersion; (2) Disperse Co / CuFe2O4 nanoparticles in anhydrous ethanol and sonicate for 20-40 min to form a Co / CuFe2O4 dispersion; (3) The graphene oxide dispersion and the Co / CuFe2O4 dispersion were mixed at a mass ratio of 1:0.5-2. After stirring for 20-40 minutes, the mixture was transferred to a reaction vessel lined with polyethylene tetroxide. The mixture was then subjected to hydrothermal reaction at 175-185℃ for 10-14 hours. After centrifugation and washing, the reaction product was vacuum dried at 55-65℃ for 20-30 hours to finally obtain the Co / CuFe2O4@GO ternary composite material.

9. A Co / CuFe2O4@GO ternary composite material, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the Co / CuFe2O4@GO ternary composite material according to claim 9 in the photo-Fenton degradation of oxytetracycline.

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