CoMoO4 / BiVO4 nano material, preparation method and application

Abstract

The invention discloses a CoMoO4 / BiVO4 nano material, a preparation method and application, CoMoO4 and BiVO4 are used as raw materials, CoMoO4 and BiVO4 are mixed according to a certain mass, and the CoMoO4 / BiVO4 nano material is successfully prepared through a hydrothermal reaction and calcination treatment. When the CoMoO4 / BiVO4 nano material is used as a photocatalyst for degrading levofloxacin hydrochloride in antibiotic wastewater, the CoMoO4 / BiVO4 nano material shows excellent visible light absorption performance and photocatalytic oxidation activity, so that the CoMoO4 / BiVO4 nano material can be used for photocatalytic degradation of levofloxacin hydrochloride pollutants. In addition, the preparation method has the characteristics of simple process, easy operation, easily available raw materials and the like, and is suitable for industrial production and popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterial synthesis, and particularly relates to a CoMoO4 / BiVO4 nanomaterial, a preparation method and an application thereof. Background Art

[0002] Antibiotic wastewater is a common source of water pollution, mainly from hospitals, pharmaceutical factories and livestock farms. These wastewaters contain a large amount of antibiotic residues and metabolites, resulting in excessive antibiotic concentrations in natural waters. Due to the weak absorption ability of animals to antibiotics, the widespread use of antibiotics has led to their residual release and accumulation in wastewater, fresh water and seawater, and thus migrated into the food chain, posing potential hazards to the water ecosystem and human health. Therefore, designing a rapid and effective method for efficiently treating antibiotic-contaminated wastewater is considered essential.

[0003] Photocatalytic degradation is one of the new technologies for combating antibiotics and purifying the environment. In order to obtain environmentally friendly functional materials to combat residual antibiotic pollution, scientists have begun to conduct photocatalytic experiments using semiconductors, and the application of semiconductor photocatalytic technology to degrade antibiotics in water has been proven to be a promising technology.

[0004] The key to semiconductor photocatalytic technology is to construct an efficient and stable photocatalyst. So far, various photocatalysts have been reported, such as TiO2, Ag2MoO4, Bi2WO6, MoS2, C3N4, BiVO4 and WO3. Among them, the bismuth-based material BiVO4 is recognized as an efficient visible-light-responsive photocatalyst with broad application prospects because of its characteristics such as narrow bandgap (2.4 eV), visible-light responsiveness, n-type characteristics, non-toxicity, anti-photocorrosion and strong oxidizing ability for decomposing organic pollutants. However, when BiVO4 is used alone as a photocatalytic material in practical applications, it shows low photocatalytic efficiency, resulting in serious limitations in its large-scale application. Summary of the Invention

[0005] Aiming at the problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a CoMoO4 / BiVO4 nanomaterial, a preparation method and an application thereof.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] The first aspect of the present invention is to provide a preparation method of a CoMoO4 / BiVO4 nanomaterial, comprising the following steps:

[0008] S1. Prepare CoMoO4 nanoparticles:

[0009] Dissolve Co(NO3)2·6H2O and Na2MoO4 in deionized water respectively to obtain Co(NO3)2 solution and Na2MoO4 solution; mix the Co(NO3)2 solution and Na2MoO4 solution, then transfer them to an autoclave for reaction. After the reaction is completed, naturally cool to room temperature, filter the lower precipitate, wash, dry, grind into powder, and place it in a muffle furnace for calcination to obtain CoMoO4 nanoparticles;

[0010] S2. Preparation of BiVO4 nanomaterials:

[0011] First, dissolve Bi(NO3)3·5H2O in HNO3 solution to obtain solution A, and dissolve NH4VO3 in NaOH solution to obtain solution B; then add solution B to solution A, and adjust the pH of the system to 9.0 - 10.0 after addition to obtain BiVO4 nanomaterials;

[0012] S3. Preparation of CoMoO4 / BiVO4 nanomaterials: Add CoMoO4 nanoparticles to BiVO4 nanomaterials and stir to mix, then place the mixed solution in a reaction kettle for hydrothermal reaction. After natural cooling, wash the reaction product with deionized water and absolute ethanol, centrifuge, dry, and finally place it in a muffle furnace for calcination treatment to obtain CoMoO4 / BiVO4 nanomaterials.

[0013] Preferably, in step S1, the molar ratio of Co(NO3)2·6H2O to Na2MoO4 is 1:1 - 1.2.

[0014] Preferably, in step S1, the reaction temperature is 120 - 180 °C and the reaction time is 3 - 8 h.

[0015] Preferably, in step S1, the conditions for the calcination treatment are: the heating rate is 2 - 6 °C / min, the calcination temperature is 200 - 500 °C, and the calcination time is 0.5 - 3 h.

[0016] Preferably, in step S2, the molar ratio of Bi(NO3)3·5H2O to NH4VO3 is 1:1 - 1.2.

[0017] Preferably, in step S3, the temperature of the hydrothermal reaction is 60 - 180 °C and the hydrothermal reaction time is 12 - 36 h.

[0018] Preferably, in step S3, the conditions for the calcination treatment are: the heating rate is 3 - 10 °C / min, the calcination temperature is 200 - 500 °C, and the calcination time is 1 - 4 h.

[0019] The second aspect of the present invention lies in providing the CoMoO4 / BiVO4 nanomaterials prepared by the above preparation method.

[0020] Preferably, in the CoMoO4 / BiVO4 nanomaterial, the percentage content of CoMoO4 nanoparticles is 1-5 wt%.

[0021] The third aspect of the present invention lies in providing the application of the above-mentioned CoMoO4 / BiVO4 nanomaterial as a photocatalyst in the degradation of levofloxacin hydrochloride in antibiotic wastewater.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) The present invention uses CoMoO4 and BiVO4 as raw materials, and successfully prepares CoMoO4 / BiVO4 nanomaterial by mixing them in a certain mass and then performing hydrothermal reaction and calcination treatment. The obtained CoMoO4 / BiVO4 nanomaterial has a nanorod-like microstructure.

[0024] (2) The preparation method of the present invention has the characteristics of simple process, easy operation, and easy availability of raw materials, and is suitable for industrial production and promotion.

[0025] (3) When the CoMoO4 / BiVO4 nanomaterial prepared by the present invention is used as a photocatalyst for the degradation of levofloxacin hydrochloride in antibiotic wastewater, it exhibits excellent visible light absorption performance and photocatalytic oxidation activity. Therefore, it can be used for photocatalytic degradation of levofloxacin hydrochloride pollutants. Description of the Drawings

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0027] Figure 1 SEM of the CoMoO4 / BiVO4 nanomaterial prepared in Example 1 Figure 1 (200 nm scale);

[0028] Figure 2 SEM of the CoMoO4 / BiVO4 nanomaterial prepared in Example 1 Figure 2 (10 μm scale);

[0029] Figure 3 XRD pattern of the CoMoO4 / BiVO4 nanomaterial prepared in Examples 1-5;

[0030] Figure 4 Infrared spectrum of the CoMoO4 / BiVO4 nanomaterial prepared in Examples 1-5;

[0031] Figure 5 Fluorescence spectra of the CoMoO4 / BiVO4 nanomaterials prepared in Examples 1-5;

[0032] Figure 6 UV-visible absorption spectra of the CoMoO4 / BiVO4 nanomaterials prepared in Examples 1-5;

[0033] Figure 7 Photocatalytic oxidation activity results of the CoMoO4 / BiVO4 nanomaterial prepared in Example 1, the pure BiVO4 nanomaterial prepared in Comparative Example 1, and CoMoO4;

[0034] Figure 8 Degradation result graphs of the CoMoO4 / BiVO4 nanomaterials prepared in Examples 1-5, the pure BiVO4 nanomaterial prepared in Comparative Example 1, and CoMoO4 as photocatalysts for the catalytic degradation of levofloxacin hydrochloride; Detailed implementation manners

[0035] In the following description, specific details such as specific system structures and technologies are presented for the purpose of illustration rather than limitation, so as to thoroughly understand the embodiments of the present invention. However, those skilled in the art should clearly understand that the present invention can also be implemented in other embodiments without these specific details.

[0036] Example 1

[0037] A preparation method of a CoMoO4 / BiVO4 nanomaterial, comprising the following steps:

[0038] (1) Dissolve 2 mmol of Co(NO3)2·6H2O and 2 mmol of Na2MoO4 in 20 mL of deionized water respectively. After fully stirring and dissolving, obtain a Co(NO3)2 solution and a Na2MoO4 solution; mix the Co(NO3)2 solution and the Na2MoO4 solution, then transfer them to a 100 mL autoclave, react at 150 °C for 5 h, naturally cool to room temperature after the reaction, filter the lower precipitate, wash it repeatedly with absolute ethanol and deionized water, centrifuge, dry at 60 °C for 12 h, grind it into powder, and finally place the obtained light purple powder in a muffle furnace, heat it to 300 °C at a heating rate of 3 °C / min, and calcine for 1 h to obtain light purple CoMoO4 nanoparticles;

[0039] (2) Dissolve 2mmol Bi(NO3)3·5H2O in 5mL 4M HNO3 solution to obtain solution A; dissolve 2mmol NH4VO3 in 50mL 2M NaOH solution to obtain solution B; slowly dropwise add solution B to solution A while stirring, and keep stirring continuously during the process. After the dropwise addition is completed, adjust the pH of the system to 9.0 to obtain a BiVO4 (nanomaterial) solution;

[0040] (3) Weigh 0.263 g of CoMoO4 nanoparticles and add them to the BiVO4 (nanomaterial) solution, stir for 30 min, then transfer to a 100 mL reactor, perform hydrothermal reaction at 120°C for 24 h, naturally cool to room temperature, separate the solid and liquid, repeatedly wash with deionized water and anhydrous ethanol, centrifuge, dry at 60°C, and finally place in a muffle furnace and heat to 300°C at 3°C / min, calcine for 1 h to obtain a CoMoO4 / BiVO4 composite material, recorded as 3wt% CoMoO4 / BiVO4 nanomaterial.

[0041] Example 2

[0042] (1) 2 mmol Co(NO3)2·6H2O and 2 mmol Na2MoO4 were dissolved in 20 mL of deionized water, respectively, and stirred thoroughly to obtain Co(NO3)2 solution and Na2MoO4 solution; the Co(NO3)2 solution and the Na2MoO4 solution were mixed, and then transferred to a 100 mL autoclave, reacted at 150°C for 5 h, and naturally cooled to room temperature after the reaction was completed. The lower precipitate was filtered, repeatedly washed with anhydrous ethanol and deionized water, centrifuged, dried at 60°C for 12 h, and ground into powder. Finally, the obtained lavender powder was placed in a muffle furnace, heated to 300°C at a heating rate of 3°C / min, and calcined for 1 h to obtain lavender CoMoO4 nanoparticles;

[0043] (2) Dissolve 2mmol Bi(NO3)3·5H2O in 5mL 4M HNO3 solution to obtain solution A; dissolve 2mmol NH4VO3 in 50mL 2M NaOH solution to obtain solution B; slowly dropwise add solution B to solution A while stirring, and keep stirring continuously during the process. After the dropwise addition is completed, adjust the pH of the system to 9.0 to obtain a BiVO4 (nanomaterial) solution;

[0044] (3) Weigh 0.087 g of light purple CoMoO4 nanoparticles and add them to the BiVO4 solution. Stir for 30 min, then transfer to a 100 mL autoclave and carry out a hydrothermal reaction at 60 °C for 36 h. Naturally cool to room temperature, separate the solid and liquid, wash the obtained precipitate repeatedly with deionized water and absolute ethanol, centrifuge, dry at 60 °C, then place it in a muffle furnace, heat it to 300 °C at a rate of 3 °C / min, and calcine for 1 h to obtain the CoMoO4 / BiVO4 composite material, denoted as 1 wt% CoMoO4 / BiVO4 nanomaterial.

[0045] Example 3

[0046] (1) Dissolve 2 mmol of Co(NO3)2·6H2O and 2 mmol of Na2MoO4 in 20 mL of deionized water respectively. After fully stirring and dissolving, obtain the Co(NO3)2 solution and the Na2MoO4 solution; mix the Co(NO3)2 solution and the Na2MoO4 solution, then transfer to a 100 mL autoclave and react at 150 °C for 5 h. After the reaction, naturally cool to room temperature, filter the lower-layer precipitate, wash it repeatedly with absolute ethanol and deionized water, centrifuge, dry at 60 °C for 12 h, grind it into powder, and finally place the obtained light purple powder in a muffle furnace, heat it to 300 °C at a heating rate of 3 °C / min, and calcine for 1 h to obtain light purple CoMoO4 nanoparticles;

[0047] (2) Dissolve 2 mmol of Bi(NO3)3·5H2O in 5 mL of 4 M HNO3 solution to obtain solution A; dissolve 2 mmol of NH4VO3 in 50 mL of 2 M NaOH solution to obtain solution B; slowly drop solution B into solution A while stirring, and keep stirring continuously during this process. After dropping, adjust the pH of the system to 9.0 to obtain the BiVO4 (nanomaterials) solution;

[0048] (3) Weigh 0.175 g of CoMoO4 nanoparticles and add them to the BiVO4 solution. Stir for 30 min, then transfer to a 100 mL autoclave and carry out a hydrothermal reaction at 90 °C for 30 h. Naturally cool to room temperature, separate the solid and liquid, wash it repeatedly with deionized water and absolute ethanol, centrifuge, dry at 60 °C, and finally place it in a muffle furnace and heat it to 300 °C at a rate of 3 °C / min, and calcine for 1 h to obtain the CoMoO4 / BiVO4 composite material, denoted as 2 wt% CoMoO4 / BiVO4 nanomaterial.

[0049] Example 4

[0050] (1) Dissolve 2 mmol of Co(NO3)2·6H2O and 2 mmol of Na2MoO4 in 20 mL of deionized water respectively. After fully stirring and dissolving, obtain Co(NO3)2 solution and Na2MoO4 solution; mix the Co(NO3)2 solution and Na2MoO4 solution, then transfer them to a 100 mL autoclave, react at 150 °C for 5 h. After the reaction, naturally cool to room temperature, filter the lower-layer precipitate, wash it repeatedly with anhydrous ethanol and deionized water, centrifuge, dry at 60 °C for 12 h, grind it into powder. Finally, place the obtained light purple powder in a muffle furnace, heat it to 300 °C at a heating rate of 3 °C / min, and calcine for 1 h to obtain light purple CoMoO4 nanoparticles;

[0051] (2) Dissolve 2 mmol of Bi(NO3)3·5H2O in 5 mL of 4M HNO3 solution to obtain solution A; dissolve 2 mmol of NH4VO3 in 50 mL of 2M NaOH solution to obtain solution B; slowly drip solution B into solution A while stirring, and keep stirring continuously during this process. After the dripping is completed, adjust the pH of the system to 9.0 to obtain BiVO4 (nanomaterials) solution;

[0052] (3) Weigh 0.350 g of CoMoO4 nanoparticles and add them to the BiVO4 solution, stir for 30 min, then transfer to a 100 mL reaction kettle, carry out hydrothermal reaction at 150 °C for 18 h, naturally cool to room temperature, separate the solid and liquid, wash repeatedly with deionized water and anhydrous ethanol, centrifuge, dry at 60 °C, and finally place it in a muffle furnace and heat it to 300 °C at a heating rate of 3 °C / min and calcine for 1 h to obtain CoMoO4 / BiVO4 composite material, denoted as 4wt% CoMoO4 / BiVO4 nanomaterials.

[0053] Example 5

[0054] (1) Dissolve 2 mmol of Co(NO3)2·6H2O and 2 mmol of Na2MoO4 in 20 mL of deionized water respectively. After fully stirring and dissolving, obtain Co(NO3)2 solution and Na2MoO4 solution; mix the Co(NO3)2 solution and Na2MoO4 solution, then transfer them to a 100 mL autoclave, react at 150 °C for 5 h. After the reaction, naturally cool to room temperature, filter the lower-layer precipitate, wash it repeatedly with anhydrous ethanol and deionized water, centrifuge, dry at 60 °C for 12 h, grind it into powder. Finally, place the obtained light purple powder in a muffle furnace, heat it to 300 °C at a heating rate of 3 °C / min, and calcine for 1 h to obtain light purple CoMoO4 nanoparticles;

[0055] (2) Dissolve 2 mmol of Bi(NO3)3·5H2O in 5 mL of 4 M HNO3 solution to obtain solution A; dissolve 2 mmol of NH4VO3 in 50 mL of 2 M NaOH solution to obtain solution B; slowly add solution B dropwise to solution A while stirring, and keep stirring continuously during this process. After the addition is complete, adjust the pH of the system to pH = 9.0 to obtain a BiVO4 (nanomaterials) solution;

[0056] (3) Weigh 0.438 g of CoMoO4 nanoparticles and add them to the BiVO4 solution. Stir for 30 min, then transfer to a 100 mL autoclave and carry out a hydrothermal reaction at 180 °C for 12 h. Naturally cool to room temperature, separate the solid and liquid, wash repeatedly with deionized water and absolute ethanol, centrifuge, dry at 60 °C, and finally place in a muffle furnace and heat up to 300 °C at a rate of 3 °C / min and calcine for 1 h to obtain the CoMoO4 / BiVO4 composite material, denoted as 5 wt% CoMoO4 / BiVO4 nanomaterials.

[0057] Example 6

[0058] (1) Dissolve 2 mmol of Co(NO3)2·6H2O and 2 mmol of Na2MoO4 in 20 mL of deionized water respectively. After fully stirring and dissolving, obtain a Co(NO3)2 solution and a Na2MoO4 solution; mix the Co(NO3)2 solution and the Na2MoO4 solution, then transfer to a 100 mL autoclave and react at 150 °C for 5 h. After the reaction is completed, naturally cool to room temperature, filter the lower layer precipitate, wash repeatedly with absolute ethanol and deionized water, centrifuge, dry at 60 °C for 12 h, grind into powder, and finally place the obtained light purple powder in a muffle furnace and heat up to 300 °C at a heating rate of 3 °C / min and calcine for 1 h to obtain light purple CoMoO4 nanoparticles;

[0059] (2) Dissolve 2 mmol of Bi(NO3)3·5H2O in 5 mL of 4 M HNO3 solution to obtain solution A; dissolve 2 mmol of NH4VO3 in 50 mL of 2 M NaOH solution to obtain solution B; slowly add solution B dropwise to solution A while stirring, and keep stirring continuously during this process. After the addition is complete, adjust the pH of the system to pH = 9.0 to obtain a BiVO4 (nanomaterials) solution;

[0060] (3) Weigh 0.263 g of CoMoO4 nanoparticles and add them to the BiVO4 solution. Stir for 30 min, then transfer to a 100 mL autoclave and carry out a hydrothermal reaction at 120 °C for 18 h. Naturally cool to room temperature, separate the solid and liquid, wash repeatedly with deionized water and absolute ethanol, centrifuge, dry at 60 °C, and finally place in a muffle furnace and heat to 200 °C at a rate of 6 °C / min and calcine for 4 h to obtain the CoMoO4 / BiVO4 nanomaterial.

[0061] Example 7

[0062] (1) Dissolve 2 mmol of Co(NO3)2·6H2O and 2 mmol of Na2MoO4 in 20 mL of deionized water respectively. After fully stirring and dissolving, obtain the Co(NO3)2 solution and the Na2MoO4 solution; mix the Co(NO3)2 solution and the Na2MoO4 solution, then transfer to a 100 mL autoclave and react at 150 °C for 5 h. After the reaction, naturally cool to room temperature, filter the lower precipitate, wash repeatedly with absolute ethanol and deionized water, centrifuge, dry at 60 °C for 12 h, grind into powder, and finally place the obtained light purple powder in a muffle furnace and heat to 300 °C at a heating rate of 3 °C / min and calcine for 1 h to obtain light purple CoMoO4 nanoparticles;

[0063] (2) Dissolve 2 mmol of Bi(NO3)3·5H2O in 5 mL of 4 M HNO3 solution to obtain solution A; dissolve 2 mmol of NH4VO3 in 50 mL of 2 M NaOH solution to obtain solution B; slowly add solution B dropwise to solution A while stirring, and keep stirring continuously during this process. After the addition is complete, adjust the system to pH = 9.0 to obtain the BiVO4 (nanomaterials) solution;

[0064] (3) Weigh 0.263 g of CoMoO4 nanoparticles and add them to the BiVO4 solution. Stir for 30 min, then transfer to a 100 mL autoclave and carry out a hydrothermal reaction at 150 °C for 24 h. Naturally cool to room temperature, separate the solid and liquid, wash repeatedly with deionized water and absolute ethanol, centrifuge, dry at 60 °C, and finally place in a muffle furnace and heat to 500 °C at a rate of 10 °C / min and calcine for 2 h to obtain the CoMoO4 / BiVO4 nanomaterial.

[0065] Comparative Example 1

[0066] It is basically the same as the steps of Example 1, except that CoMoO4 is not added, and pure BiVO4 nanorods are obtained.

[0067] Comparative Example 2

[0068] The procedure was basically the same as that of Example 1, except that BiVO4 was not used, and pure CoMoO4 nanoparticles were obtained.

[0069] Test characterization

[0070] The series of CoMoO4 / BiVO4 nanomaterials (1wt% CoMoO4 / BiVO4 nanomaterials, 2wt% CoMoO4 / BiVO4 nanomaterials, 3wt% CoMoO4 / BiVO4 nanomaterials, 4wt% CoMoO4 / BiVO4 nanomaterials, 5wt% CoMoO4 / BiVO4 nanomaterials) prepared in Examples 1-5, the pure BiVO4 nanorods prepared in Comparative Example 1, and the pure CoMoO4 nanoparticles prepared in Comparative Example 2 were tested and characterized. The results are shown in Figures 1-7 .

[0071] From Figure 1 and Figure 2 the results, it can be seen that the 3wt% CoMoO4 / BiVO4 nanomaterial prepared in Example 1 of the present invention has a rod-like microscopic morphology structure, and CoMoO4 is successfully loaded on the BiVO4 nanorods.

[0072] From Figure 3 the results, it can be seen that the strong peaks of pure BiVO4 nanorods appear at 2θ of 18.6°, 28.9°, and 30.5°, corresponding to the (110), (121), and (040) crystal planes of pure BiVO4 nanorods, respectively. All have diffraction characteristic peaks, which are consistent with the diffraction peak positions of standard monoclinic BiVO4. In addition, strong and sharp characteristic diffraction peaks are also found, indicating that the prepared pure sample BiVO4 has good crystallinity. The strong peaks of pure sample CoMoO4 appear at 2θ of 24.9° and 26.5°, corresponding to the (021) and (002) crystal planes of pure sample CoMoO4, respectively. The diffraction peaks are consistent with the diffraction peak positions of the CoMoO4 standard card, indicating that the two are pure phases of BiVO4 and CoMoO4. In the XRD characterization of the prepared series of CoMoO4 / BiVO4 nanomaterial samples, the characteristic peaks of the structure, composition, morphology, etc. of the CoMoO4 / BiVO4 nanomaterials obtained under different ratios were detected in the composite samples, and no peaks of other impurities were detected in the composite materials, indicating that the CoMoO4 / BiVO4 nanomaterials prepared in the present invention are composed of CoMoO4 and BiVO4, that is, the CoMoO4 / BiVO4 nanomaterials prepared in the present invention are effectively compounded from pure samples of CoMoO4 and BiVO4.

[0073] From Figure 4 the results, it can be seen that the FTIR characterization result of CoMoO4 is at 949 cm -1The peak at [specific position] corresponds to the stretching vibration of its chemical bonds, while in the infrared spectrum of BiVO4, it is at 1003 cm -1 At [specific position]. In the composite sample, the characteristic peaks of CoMoO4 and BiVO4 at 1591 cm -1 and 2331 cm -1 can both be detected, indicating that CoMoO4 / BiVO4 is composed of CoMoO4 and BiVO4.

[0074] From Figure 5 the results, it can be seen that BiVO4 has a strong fluorescence emission peak, indicating a large recombination rate of photo-generated electrons and holes. However, the strong absorption peaks of the series of CoMoO4 / BiVO4 nanomaterials are significantly lower than those of pure BiVO4. This shows that the electrons and holes are effectively separated, improving the photocatalytic performance.

[0075] From Figure 6 and Figure 7 the results, it can be known that the band gaps of pure BiVO4 nanorods and CoMoO4 nanoparticles are 2.23 eV and 2.58 eV respectively. The band gap of the 3wt% CoMoO4 / BiVO4 nanomaterial is lower than that of pure CoMoO4, being 2.34 eV. This result indicates that the CoMoO4 / BiVO4 nanomaterial prepared in this invention has better photocatalytic activity than pure BiVO4 nanorods and CoMoO4 nanoparticles, can utilize visible light more effectively, has better visible light absorption performance, and thus can greatly improve the photocatalytic performance.

[0076] Applied research

[0077] The series of CoMoO4 / BiVO4 rod-shaped composite materials prepared in Examples 1 - 5 of this invention, the pure BiVO4 nanorods prepared in Comparative Example 1, and pure CoMoO4 were respectively dissolved in a levofloxacin hydrochloride pollution solution with a concentration of 10 mg / L according to a mass ratio of 1 - 10% in a solution containing the pollutant, ultrasonically dispersed for 10 min, then magnetically stirred in the dark for 20 min. After stirring, first take 3 mL of the solution to measure the absorbance, and then irradiate with a xenon lamp as the light source. Take samples every 30 min to measure the absorbance, and calculate the content of the pollutant through the absorbance. The results are shown in Figure 8 .

[0078] From Figure 8The results show that under visible light conditions, when the pure samples of BiVO4 nanorods, CoMoO4 nanoparticles and a series of CoMoO4 / BiVO4 nanomaterials are used as photocatalysts, after 180 min of degradation, the degradation efficiencies of the two pure samples of BiVO4 nanorods and CoMoO4 nanoparticles are only 38% and 14% respectively, while the degradation effects of the series of CoMoO4 / BiVO4 nanomaterials as photocatalysts are generally higher than those of the two pure samples. Among them, the degradation efficiency of the 3wt% CoMoO4 / BiVO4 nanomaterial is the best (86%), and the degradation effects of the 2wt% CoMoO4 / BiVO4 nanomaterial, 5wt% CoMoO4 / BiVO4 nanomaterial and 4wt% CoMoO4 / BiVO4 nanomaterial increase in turn, generally in the range of 70%-82%. The above results indicate that under visible light conditions, the CoMoO4 / BiVO4 nanomaterial prepared in this invention has strong catalytic oxidation activity for levofloxacin hydrochloride pollutants, which may be attributed to the formation of a heterojunction interface between the CoMoO4 and BiVO4 phases due to a relatively appropriate doping ratio, inhibiting the recombination of electrons and holes, improving the separation efficiency of electrons and holes, and enabling electrons and holes to participate in the generation of hydroxyl radicals or superoxide radicals and further activating levofloxacin hydrochloride. Therefore, it can be used as a photocatalyst for the degradation of levofloxacin hydrochloride in antibiotic wastewater.

[0079] The present invention is not limited to the above specific embodiments. Those of ordinary skill in the art starting from the above concepts and making various transformations without creative labor fall within the protection scope of the present invention.

Claims

1. A method for preparing CoMoO4 / BiVO4 nanomaterial, characterized in that: The method comprises the following steps: mixing CoMoO4 nanoparticles with BiVO4 nanomaterials, carrying out a hydrothermal reaction, and then purifying the reaction product and calcining it to obtain the CoMoO4 / BiVO4 nanomaterial.

2. The method for preparing the CoMoO4 / BiVO4 nanomaterial according to claim 1, characterized in that: The preparation steps of the CoMoO4 nanoparticles include: dissolving Co(NO3)2·6H2O and Na2MoO4 in deionized water respectively to obtain Co(NO3)2 solution and Na2MoO4 solution; mixing the Co(NO3)2 solution and the Na2MoO4 solution, and then transferring them to an autoclave for reaction, naturally cooling to room temperature after the reaction, filtering the lower layer of precipitate, washing, drying, grinding into powder, placing in a muffle furnace for calcination, and obtaining CoMoO4 nanoparticles; the molar ratio of Co(NO3)2·6H2O and Na2MoO4 is 1:1-1.

2.

3. The method for preparing the CoMoO4 / BiVO4 nanomaterial according to claim 2, characterized in that: The reaction temperature is 120-180° C., and the reaction time is 3-8 hours.

4. The method for preparing the CoMoO4 / BiVO4 nanomaterial according to claim 2, characterized in that: The calcination treatment conditions are: heating rate of 2-6°C / min, calcination temperature of 200-500°C, and calcination time of 0.5-3h.

5. The method for preparing the CoMoO4 / BiVO4 nanomaterial according to claim 2, characterized in that: The preparation steps of the BiVO4 nanomaterial include: firstly dissolving Bi(NO3)3·5H2O in HNO3 solution to obtain solution A, dissolving NH4VO3 in NaOH solution to obtain solution B; then adding solution B to solution A, adjusting the pH of the system to 9.0-10.0, and obtaining the BiVO4 nanomaterial; the molar ratio of Bi(NO3)3·5H2O and NH4VO3 is 1:1-1.

2.

6. The method for preparing the CoMoO4 / BiVO4 nanomaterial according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 60-180° C., and the hydrothermal reaction time is 12-36 hours.

7. The method for preparing the CoMoO4 / BiVO4 nanomaterial according to claim 1, characterized in that: The calcination treatment conditions are: heating rate of 3-10°C / min, calcination temperature of 200-500°C, and calcination time of 1-4h.

8. A CoMoO4 / BiVO4 nanomaterial prepared by the preparation method according to any one of claims 1 to 7, characterized in that: In the CoMoO4 / BiVO4 nanomaterial, the mass percentage content of CoMoO4 is 1-5wt%.

9. A CoMoO4 / BiVO4 nanomaterial as claimed in claim 8 used as a photocatalyst to degrade levofloxacin hydrochloride in antibiotic wastewater.

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