A flower ball-shaped CoMoO4 loaded Fe-doped g-C3N4 composite photocatalyst, a preparation method and application thereof

Abstract

The application belongs to the technical field of photocatalytic degradation of antibiotics, and relates to a flower-spherical CoMoO4 loaded Fe-doped g-C3N4 composite photocatalyst, a preparation method and application thereof.The composite photocatalyst is composed of flower-spherical CoMoO4 loaded nanosheet Fe-doped g-C3N4, is obtained by uniformly loading Fe-doped g-C3N4 on flower-spherical CoMoO4 through an ultrasonic immersion method, wherein the Fe-doped g-C3N4 is obtained by calcining a melamine and ferric chloride hexahydrate mixture, and the flower-spherical CoMoO4 is obtained by a simple hydrothermal method.Under the synergistic effect of the composite photocatalyst and persulfate oxidant, the degradation effect can reach 77% within one minute, the reaction time is short and the efficiency is high, which provides a train of thought and means for photocatalytic activation of persulfate degradation of antibiotics, environmental protection and other fields, and has great popularization value.

Description

Technical Field

[0001] This invention belongs to the field of antibiotic photocatalytic degradation technology, specifically relating to a flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst, its preparation method, and its application. Background Technology

[0002] Antibiotics widely used in medicine and aquaculture, particularly quinolone antibiotics, a broad-spectrum class, are seeing a continuous increase in usage. Approximately 90% of these antibiotics are excreted into the natural environment through the waste of patients and livestock. The long-term presence of quinolone antibiotics in aquatic environments may lead to the development of antibiotic-resistant bacteria and antibiotic resistance genes, accelerating the spread of antibiotic resistance and posing a serious threat to aquatic ecological security, ultimately endangering human health. Currently, photocatalysis technology based on semiconductor materials is receiving widespread attention due to its highly efficient degradation of organic matter and environmentally friendly characteristics.

[0003] Existing literature often employs photocatalysis for the direct degradation of quinolone antibiotics, but this method is time-consuming and inefficient. Therefore, combining photocatalysts with oxidants is considered. For example, persulfate, a strong oxidant, can be directly added to the aquatic environment and, under different activation conditions, can be decomposed to generate sulfate radicals (·SO4) with strong oxidizing power. - It can oxidize and decompose organic matter, eventually converting it into non-toxic small molecules, and has the advantages of fast reaction speed and wide range of applications.

[0004] Graphitic carbon nitride (g-C3N4) is a typical polymer semiconductor that responds to visible light in the 400-600 nm range, and is therefore widely used in photocatalysis. However, the inherent limitations of g-C3N4 result in low catalytic activity in photocatalytic reactions, which cannot meet the needs of practical production. Currently, methods such as morphology manipulation, elemental doping, and the construction of heterojunctions are commonly used to improve its catalytic activity in photocatalytic reactions. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: in order to overcome the above problems, the present invention provides a method for preparing a flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst, which is prepared by combining flower-shaped CoMoO4 and nanosheet-shaped Fe-doped g-C3N4, wherein the mass of Fe-doped g-C3N4 is 20%-80% of the mass of flower-shaped CoMoO4.

[0007] Preferably, the mass of the Fe-doped g-C3N4 is 40% of the mass of the flower-shaped CoMoO4.

[0008] The preparation method of the above-mentioned flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst includes the following steps:

[0009] (1) Preparation of Fe-doped g-C3N4: Melamine and ferric chloride hexahydrate were mixed and ground thoroughly for 30 min. The mixture was then calcined to obtain block g-C3N4. The block g-C3N4 was calcined again under the same conditions. Then it was added to ethanol, sonicated continuously for 3 h, and dried to obtain sheet-like Fe-doped g-C3N4.

[0010] (2) Preparation of flower-shaped CoMoO4: Co(NO3)2·6H2O, Na2MoO4 and urea were stirred in distilled water until fully dissolved and dispersed, transferred to a stainless steel autoclave made of polytetrafluoroethylene, and kept at 110-130℃ for 24h. After cooling to room temperature, the precursor was collected by centrifugation. The mixture was then placed in a tube furnace for heat treatment to obtain flower-shaped CoMoO4, wherein the mass ratio of Co(NO3)2·6H2O, Na2MoO4 and urea was 1:1:1.

[0011] (3) Preparation of flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst: Flower-shaped CoMoO4 and Fe-doped g-C3N4 were dispersed in ethanol and sonicated until fully dispersed to obtain ethanol solutions of flower-shaped CoMoO4 and Fe-doped g-C3N4. The ethanol solution of flower-shaped CoMoO4 was added dropwise to the ethanol solution of Fe-doped g-C3N4 and sonicated until uniform. Then, acetone was added and stirred for 20-24 hours. After washing several times and drying, the flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst was obtained.

[0012] Furthermore, the calcination method described in step (1) is as follows: the temperature is increased to 500-550℃ at a rate of 2-5℃ / min and maintained for 3-5 hours.

[0013] Furthermore, the mass ratio of melamine to ferric chloride hexahydrate in step (1) is 10:1.

[0014] Furthermore, the amount of Co(NO3)2·6H2O, Na2MoO4 and urea used in step (2) determines the morphology of the obtained flower-shaped CoMoO4. Preferably, the mass ratio of Co(NO3)2·6H2O, Na2MoO4 and urea is 1:1:1, which can obtain a more uniform flower-shaped CoMoO4.

[0015] Furthermore, the heat treatment in step (2) is as follows: heating to 480-500℃ at a heating rate of 3-5℃ / min under a nitrogen atmosphere and holding for 4-5h.

[0016] The flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst prepared by the above method is applied to the degradation of antibiotics. The specific steps are as follows: the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst and persulfate are added to a solution containing norfloxacin, and catalytic degradation is carried out under light irradiation.

[0017] Furthermore, the antibiotic is norfloxacin; the persulfate includes potassium persulfate.

[0018] Furthermore, the illumination includes natural light and simulated sunlight. The simulated sunlight source is a xenon lamp.

[0019] This invention obtains bulk Fe-doped g-C3N4 by calcining melamine and ferric chloride hexahydrate, followed by secondary calcination and ultrasonication to obtain sheet-like Fe-doped g-C3N4. Flower-shaped CoMoO4 is prepared by a simple hydrothermal method. Fe-doped g-C3N4 is uniformly loaded onto flower-shaped CoMoO4 by ultrasonic impregnation to obtain a flower-shaped composite photocatalyst, which can be applied to the field of photocatalytic activation of persulfate.

[0020] Compared with the prior art, the technical solution of the present invention achieves the following beneficial technical effects:

[0021] (1) The present invention uses Fe-doped g-C3N4 and flower-shaped CoMoO4 to prepare a flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst. The composite photocatalyst and persulfate oxidant can achieve a synergistic degradation effect of 86% of norfloxacin, and its degradation effect within one minute can reach 77%, with short reaction time and high efficiency.

[0022] (2) The present invention uses ultrasonic impregnation to prepare composite photocatalysts, which is simple, easy to carry out, and has good reproducibility. It provides ideas and means for photocatalytic activation of persulfate, environmental protection and other fields, and has great promotion value. Attached Figure Description

[0023] The invention will be further described below with reference to the accompanying drawings.

[0024] Figure 1 The X-ray diffraction patterns are of Fe-doped g-C3N4 (FCN), flower-shaped CoMoO4 (CMO), and 0.2-0.8FCN-CMO prepared in Example 1.

[0025] Figure 2This is a SEM image of the Fe-doped g-C3N4 obtained in Example 1;

[0026] Figure 3 These are SEM images of the flower-shaped CoMoO4 obtained in Examples 1 and 6-7, where (ab) is Example 6, (c) is Example 7, and (d) is Example 1.

[0027] Figure 4 This is a SEM image of the 0.4FCN-CMO composite photocatalyst;

[0028] Figure 5 The graph shows the degradation effect of flower-shaped CoMoO4 and 0.2-0.8FCN-CMO prepared in Example 1 (the shaded area from 0-30 min in the graph represents the dark reaction);

[0029] Figure 6 The graph shows the degradation effect of 0.4FCN-CMO under different conditions (the shaded area from 0 to 30 min in the graph represents the dark reaction);

[0030] Figure 7 This is a photocatalytic experiment cycle diagram of 0.4FCN-CMO in Example 2 of the present invention. Detailed Implementation

[0031] This invention is not limited to the specific embodiments listed below. Those skilled in the art can implement this invention using various other specific embodiments based on the content disclosed herein. Any modifications or alterations made to the design structure and concept of this invention fall within the protection scope of this invention. It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0032] The present invention will be further described in detail below with reference to the embodiments:

[0033] Example 1

[0034] (1) Preparation of Fe-doped g-C3N4: Melamine and ferric chloride hexahydrate were mixed at a mass ratio of 10:1 and ground thoroughly for 30 min. The mixture was heated to 550℃ at a heating rate of 3℃ / min and calcined for 5 h to obtain block g-C3N4. The block g-C3N4 was calcined again under the same conditions at 550℃ for 5 h. Then it was added to ethanol and sonicated continuously for 3 h. After drying, sheet-like Fe-doped g-C3N4 was obtained.

[0035] (2) Preparation of flower-shaped CoMoO4: Co(NO3)2·6H2O, Na2MoO4 and urea were stirred in distilled water until fully dissolved and dispersed, transferred to a stainless steel autoclave made of polytetrafluoroethylene, and kept at 120℃ for 24h. After cooling to room temperature, the precursor was collected by centrifugation. The mixture was then placed in a tube furnace and heated to 500℃ at a heating rate of 5℃ / min under a nitrogen atmosphere and kept for 5h to obtain flower-shaped CoMoO4, wherein the mass ratio of Co(NO3)2·6H2O, Na2MoO4 and urea was 1:1:1.

[0036] (3) Preparation of flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst: 50 mg CoMoO4 and 10 mg Fe-doped g-C3N4 were dispersed in ethanol and sonicated until fully dispersed to obtain ethanol solutions of CoMoO4 and Fe-doped g-C3N4. The ethanol solution of CoMoO4 was added dropwise to the ethanol solution of Fe-doped g-C3N4 and sonicated until uniform. Then acetone was added and stirred for 24 h. After washing several times and drying, the flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst was obtained, which is referred to as 0.2FCN-CMO.

[0037] Example 2

[0038] (1) Same as Example 1;

[0039] (2) Same as Example 1;

[0040] (3) Preparation of flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst: 50 mg CoMoO4 and 20 mg Fe-doped g-C3N4 were dispersed in ethanol and sonicated until fully dispersed to obtain ethanol solutions of CoMoO4 and Fe-doped g-C3N4. The ethanol solution of CoMoO4 was added dropwise to the ethanol solution of Fe-doped g-C3N4 and sonicated until uniform. Then acetone was added and stirred for 20-24 h. After washing several times and drying, the flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst was obtained, which is referred to as 0.4FCN-CMO.

[0041] Example 3

[0042] (1) Same as Example 1;

[0043] (2) Same as Example 1;

[0044] (3) Preparation of flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst: 50 mg CoMoO4 and 30 mg Fe-doped g-C3N4 were dispersed in ethanol and sonicated until fully dispersed to obtain ethanol solutions of CoMoO4 and Fe-doped g-C3N4. The ethanol solution of CoMoO4 was added dropwise to the ethanol solution of Fe-doped g-C3N4 and sonicated until uniform. Then acetone was added and stirred for 20-24 h. After washing several times and drying, the flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst was obtained, which is referred to as 0.6FCN-CMO.

[0045] Example 4

[0046] (1) Same as Example 1;

[0047] (2) Same as Example 1;

[0048] (3) Preparation of flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst: 50 mg CoMoO4 and 40 mg Fe-doped g-C3N4 were dispersed in ethanol and sonicated until fully dispersed to obtain ethanol solutions of CoMoO4 and Fe-doped g-C3N4. The ethanol solution of CoMoO4 was added dropwise to the ethanol solution of Fe-doped g-C3N4 and sonicated until uniform. Then acetone was added and stirred for 20-24 h. After washing several times and drying, the flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst was obtained, which is referred to as 0.8FCN-CMO.

[0049] Example 5

[0050] Preparation of flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst: Melamine and ferric chloride hexahydrate were mixed and ground thoroughly for 30 min to obtain mixture A. Co(NO3)2·6H2O, Na2MoO4 and urea in a mass ratio of 1:1:1 were stirred in distilled water until fully dissolved and dispersed. Then, mixture A was added and transferred to a polytetrafluoroethylene stainless steel autoclave. The mixture was kept at 120℃ for 24 h. After cooling to room temperature, the precursor was collected by centrifugation. The mixture was then placed in a tube furnace and heated to 500℃ at a heating rate of 5℃ / min under a nitrogen atmosphere and kept for 5 h. The resulting flower-shaped composite photocatalyst was designated as 0.4FCN-CMO-C.

[0051] Example 6

[0052] Preparation of flower-shaped CoMoO4: Co(NO3)2·6H2O, Na2MoO4 and urea were stirred in distilled water until fully dissolved and dispersed. The mixture was then transferred to a stainless steel autoclave made of polytetrafluoroethylene and kept at 120°C for 24 h. After cooling to room temperature, the precursor was collected by centrifugation. The mixture was then placed in a tube furnace and heated to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere and kept at 5 h to obtain flower-shaped CoMoO4, wherein the mass ratio of Co(NO3)2·6H2O, Na2MoO4 and urea was 3:2:1 and 2:2:1, respectively.

[0053] Example 7

[0054] Preparation of flower-shaped CoMoO4: Co(NO3)2·6H2O, Na2MoO4 and urea were stirred in distilled water until fully dissolved and dispersed. The mixture was then transferred to a stainless steel autoclave made of polytetrafluoroethylene and kept at 160℃ for 24 h. After cooling to room temperature, the precursor was collected by centrifugation. The mixture was then placed in a tube furnace and heated to 500℃ at a heating rate of 5℃ / min under a nitrogen atmosphere and kept at 5 h to obtain flower-shaped CoMoO4, wherein the mass ratio of Co(NO3)2·6H2O, Na2MoO4 and urea was 1:1:1.

[0055] The crystal structures of the flower-shaped CoMoO4, Fe-doped g-C3N4, and 0.2-0.8FCN-CMO prepared in Examples 1-4 were analyzed using a Rigaku D / max2500PC rotating X-ray diffractometer. The X-ray diffraction patterns are shown below. Figure 1 As shown, Fe-doped g-C3N4 exhibits two typical (100) and (002) diffraction peaks, centered at 13.1° and 27.8°, respectively. The peak positions of CoMoO4 are consistent with the standard card; the peak positions of FCN-CMO are consistent with the pure sample, fully demonstrating the successful synthesis of the two-phase mixture.

[0056] The morphology and structure of the Fe-doped g-C3N4 prepared in Examples 1-4 were analyzed using a JSM-6360A scanning electron microscope (JSM-6360A, Japan). Figure 2 The scanning electron microscope image shows that Fe-doped g-C3N4 appears as thin sheets.

[0057] The morphology and structure of the flower-shaped CoMoO4 (CMO) prepared in Examples 1-4 and 6-7 were analyzed using a JSM-6360A scanning electron microscope (JSM-6360A, Japan). Figure 3Scanning electron microscopy (SEM) images show that the morphology of CoMoO4 varies under different experimental conditions. When the raw material ratio changes, it is impossible to form well-formed flower-like structures. When the hydrothermal reaction temperature is increased to 160℃, the resulting CoMoO4 nanosheets are thicker. In other words, changes in reaction conditions lead to a decrease in the specific surface area of ​​the flower-like CoMoO4 and a weakening of its catalytic performance.

[0058] The 0.4FCN-CMO composite photocatalyst prepared in Example 2 was analyzed using a JSM-6360A scanning electron microscope (JSM-6360A, Japan). Figure 4 Scanning electron microscopy images show that the composite photocatalyst has a rough, spherical structure.

[0059] The 0.2-0.8 FCN-CMO prepared in Examples 1-4 was used as a photocatalyst for the degradation of norfloxacin. 2 mg of the photocatalyst was added to 50 mL of a 10 mg / L norfloxacin aqueous solution, and a 1000 W xenon lamp was used as the light source to carry out the photocatalytic activation of the persulfate degradation reaction. The dark reaction lasted for 30 minutes. After the dark reaction, potassium persulfate was added to the solution to make the concentration of potassium persulfate in the solution 0.15 mM. After illumination, 3 mL of the suspension was pipetted every 1 minute using a 3 mL pipette, and this was repeated 5 times. The suspension was then analyzed using a UV-Vis absorption spectrometer. Figure 5 It can be seen that the degradation efficiency of norfloxacin by the 0.4FCN-CMO composite photocatalyst can reach 86% within 40 minutes, indicating that the prepared 0.4FCN-CMO composite photocatalyst has high photocatalytic activity.

[0060] To verify the degradation effect of the 0.2-0.8FCN-CMO prepared in Example 2, and to compare it with the 0.4FCN-CMO-C prepared in situ in Example 5, degradation experiments were conducted under different experimental conditions: with / without potassium persulfate, with / without light. Figure 6 It can be seen that when both light and persulfate participate in the reaction, the 0.4FCN-CMO catalyst exhibits the best degradation effect, while the sample prepared by the in-situ method has a poor effect.

[0061] To verify the stability of the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst prepared in this invention, a photocatalytic cycling test was conducted on the 0.4FCN-CMO prepared in Example 2. The experimental results are as follows: Figure 7 As shown, the degradation rate of norfloxacin can still reach more than 80% after four cycles, indicating that the flower-shaped CoMoO4 supported Fe-doped g-C3N4 composite photocatalyst has good stability.

[0062] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst, characterized in that, The composite photocatalyst is prepared by combining flower-shaped CoMoO4 and nanosheet-shaped Fe-doped g-C3N4, with the mass of Fe-doped g-C3N4 being 40%-60% of the mass of flower-shaped CoMoO4; the application of the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst in the degradation of antibiotics; the antibiotic being norfloxacin. The preparation method of the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst includes the following steps: dispersing flower-shaped CoMoO4 and Fe-doped g-C3N4 separately in ethanol and sonicating until fully dispersed to obtain an ethanol solution of flower-shaped CoMoO4 and an ethanol solution of Fe-doped g-C3N4; adding the flower-shaped CoMoO4 ethanol solution dropwise to the Fe-doped g-C3N4 ethanol solution and continuing to sonicate until uniform; then adding acetone and stirring for 20-24 h; washing several times; and drying to obtain the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst. The preparation method of the flower-shaped CoMoO4 is as follows: Co(NO3)2·6H2O, Na2MoO4 and urea are stirred in distilled water until fully dissolved and dispersed, transferred to a stainless steel autoclave made of polytetrafluoroethylene, and kept at 110-130℃ for 24 h. After cooling to room temperature, the precursor is collected by centrifugation, and then the mixture is placed in a tube furnace for heat treatment to obtain flower-shaped CoMoO4.

2. A method for preparing the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst according to claim 1, characterized in that, The steps include the following: Flower-shaped CoMoO4 and Fe-doped g-C3N4 were dispersed in ethanol and sonicated until fully dispersed to prepare ethanol solutions of flower-shaped CoMoO4 and Fe-doped g-C3N4. The ethanol solution of flower-shaped CoMoO4 was added dropwise to the ethanol solution of Fe-doped g-C3N4 and sonicated until homogeneous. Then, acetone was added and stirred for 20-24 h. After washing several times and drying, the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst was obtained. The preparation method of the flower-shaped CoMoO4 is as follows: Co(NO3)2·6H2O, Na2MoO4 and urea are stirred in distilled water until fully dissolved and dispersed, transferred to a stainless steel autoclave made of polytetrafluoroethylene, and kept at 110-130℃ for 24 h. After cooling to room temperature, the precursor is collected by centrifugation, and then the mixture is placed in a tube furnace for heat treatment to obtain flower-shaped CoMoO4.

3. The method for preparing the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst according to claim 2, characterized in that: The preparation method of Fe-doped g-C3N4 is as follows: melamine and ferric chloride hexahydrate are mixed and ground thoroughly for 30 min, heated to 500-550℃ at 2-5℃ / min, and calcined for 3-5 h to obtain block g-C3N4. The block g-C3N4 is then calcined a second time under the same conditions, and then added to ethanol, continuously sonicated for 3 h, and dried to obtain sheet-like Fe-doped g-C3N4.

4. The method for preparing the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst according to claim 3, characterized in that: The mass ratio of melamine to ferric chloride hexahydrate is 10:

1.

5. The method for preparing the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst according to claim 2, characterized in that: The mass ratio of Co(NO3)2·6H2O, Na2MoO4 and urea is 1:1:

1.

6. The method for preparing the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst according to claim 2, characterized in that: The heat treatment is as follows: heating to 480-500℃ at a heating rate of 3-5℃ / min under a nitrogen atmosphere and holding for 4-5 h.

7. The application of the flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst according to claim 1, characterized in that, The process involves adding a flower-shaped CoMoO4-supported Fe-doped g-C3N4 composite photocatalyst and persulfate to a solution containing norfloxacin, and then catalytically degrading it under light irradiation.

8. The application according to claim 7, characterized in that, The persulfate includes potassium peroxymonosulfate; the illumination includes natural light and simulated sunlight, and the simulated sunlight source is a xenon lamp.

Images