阅读说明：本技术 一种一维氧化镍/钼钨酸铋固溶体光催化材料及其制备方法与应用 (One-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material and preparation method and application thereof ) 是由 李倩茹 王翠青 刘涛 于 2021-10-11 设计创作，主要内容包括：本发明涉及一种一维氧化镍/钼钨酸铋固溶体光催化材料及其制备方法与应用,属于无机光催化材料技术领域。所述一维氧化镍/钼钨酸铋的微观形貌为中空纳米管；中空纳米管的直径为100-500nm,纳米管壁厚为50-150nm,长度为5-20μm。本发明能够提供大量的活性位点,有利于光生载流子的输送与分离,从而提高光催化降解性能；同时本发明光催化材料能有效去除四环素溶液的生物毒性；最后本发明制备的光催化材料形貌均一、连续性好、循环稳定性好,降低了生产成本,提升了经济效益。(The invention relates to a one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material, a preparation method and application thereof, and belongs to the technical field of inorganic photocatalytic materials. The microscopic morphology of the one-dimensional nickel oxide/molybdenum bismuth tungstate is a hollow nanotube; the diameter of the hollow nanotube is 100-500nm, the wall thickness of the nanotube is 50-150nm, and the length is 5-20 μm. The invention can provide a large number of active sites, which is beneficial to the transportation and separation of photon-generated carriers, thereby improving the photocatalytic degradation performance; meanwhile, the photocatalytic material can effectively remove the biotoxicity of the tetracycline solution; finally, the photocatalytic material prepared by the method has the advantages of uniform appearance, good continuity and good cycling stability, reduces the production cost and improves the economic benefit.)

1. A one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material is characterized in that the microscopic morphology of the one-dimensional nickel oxide/molybdenum bismuth tungstate is a hollow nanotube.

2. The one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material as recited in claim 1, wherein the hollow nanotube has a diameter of 100-500nm, a nanotube wall thickness of 50-150nm, and a length of 5-20 μm.

3. A method of preparing a one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material as claimed in claim 2 or 3, wherein the method comprises the steps of:

(1) dissolving ammonium molybdate, ammonium metatungstate, bismuth nitrate and a nickel source in a mixed solution A consisting of absolute ethyl alcohol and N, N-dimethylformamide, adjusting the pH of the solution to be 1.0-4.0, then adding citric acid, and stirring to obtain a nickel oxide/molybdenum bismuth tungstate solution;

(2) adding the nickel oxide/molybdenum bismuth tungstate solution prepared in the step (1) into a mixed solution B consisting of absolute ethyl alcohol and N, N-dimethylformamide dissolved with polyvinylpyrrolidone (PVP), and stirring until the solution is uniformly mixed to obtain nickel oxide/molybdenum bismuth tungstate sol;

(3) performing electrostatic spinning on the nickel oxide/bismuth tungstate sol prepared in the step (2) at room temperature to obtain nickel oxide/bismuth tungstate gel fibers;

(4) and (4) putting the nickel oxide/molybdenum bismuth tungstate gel fibers prepared in the step (3) into a drying oven for drying, and then calcining in an air atmosphere to obtain the nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material.

4. The method according to claim 3, wherein the nickel source in the step (1) is nickel nitrate hexahydrate or nickel acetate tetrahydrate.

5. The production method according to claim 3, wherein the molar ratio of Mo and W in the step (1) is 1: (0-1); the molar ratio of Mo to Bi is (0-1): 2; the molar ratio of Bi to Ni is 1: 1; the molar ratio of the nickel source to the citric acid is 1: (2-6).

6. The production method according to claim 3, wherein the volume ratio of anhydrous ethanol to N, N-dimethylformamide in the step (1) is 1: 1; the molar volume ratio of the nickel source to the mixed solution A is 1: (4-10), unit mmol/mL.

7. The production method according to claim 3, wherein in the step (1), the pH of the solution is adjusted with nitric acid having a mass concentration of 66 wt%, hydrochloric acid having a mass concentration of 37 wt%, or acetic acid having a mass concentration of 99 wt%.

8. The method according to claim 3, wherein the volume ratio of the absolute ethanol to the N, N-dimethylformamide in the step (2) is 1: 4; the mass volume ratio of the polyvinylpyrrolidone to the mixed solution B is (0.8-1.0): (10-15) in g/mL.

9. The production method according to claim 3, wherein in the step (3), the electrostatic spinning is carried out at a take-in distance of 15 to 20cm, an ejection rate of 1.0 to 1.5mL/h, a voltage of 15 to 25kV, and a relative humidity of 15 to 30%.

10. The method according to claim 3, wherein the drying temperature in the step (4) is 40 to 60 ℃ and the drying time is 6 to 12 hours; the calcination temperature is 500-700 ℃, the heating rate is 1-5 ℃/min, and the heat preservation time is 1-2 h.

Technical Field

The invention relates to a one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material, a preparation method and application thereof, and belongs to the technical field of inorganic photocatalytic materials.

Background

With the development of science and technology and the improvement of living standard of people, the problem of water pollution caused by the technology is more and more serious. Among them, tetracycline is a typical broad-spectrum antibiotic, and is widely used in medical and animal husbandry, and the generated domestic sewage and medical wastewater containing a large amount of antibiotics are discharged into the environment, and the high-concentration antibiotic wastewater is not only unfavorable for the growth of plants, but also enhances the drug resistance of bacteria. Therefore, water body pollution caused by abuse or excessive use of antibiotics seriously damages the environment and ecological balance and has great influence on the health of people. Therefore, how to effectively remove antibiotics in wastewater and reduce the biological toxicity of the antibiotics so that the treated wastewater can be directly discharged into the environment is one of the major environmental problems which need to be solved urgently.

Heretofore, there have been various methods for removing antibiotics from Water bodies, such as physical adsorption (see: Bioresource Technology,2020,316,123950), biodegradation (see: Journal of Hazardous Materials,2021,408,124762), electrochemical oxidation (see: Water Research,2018,137,324-334), and photocatalytic degradation (see: Journal of Hazardous Materials,2022,422,126920). The photocatalysis can directly utilize clean energy sunlight, has the advantages of mild reaction conditions, high degradation efficiency, no secondary pollution and the like, and is an effective method for removing antibiotics in wastewater.

The core of photocatalysis is a photocatalyst, but the photocatalyst with a single component has the defects of low quantum yield, easy recombination of photogenerated electron-hole pairs, low carrier transmission rate and the like, and the photocatalytic activity of the photocatalyst is limited. At present, morphology regulation (see: Microporous and Mesoporous Materials,2021,323,111228), heterojunction construction (see: Chinese Journal of Catalysis,2020,41,1480-1487), doping (see: Catalysis Today,2021,375,506-513) and the like are effective methods for improving the photocatalytic performance. However, the energy level of the local impurity introduced by doping is easy to become a recombination center of a carrier, which is not beneficial to the improvement of the photocatalytic performance. And the solid solution method can realize the precise regulation and control of band gap and band edge position, so that the light absorption and oxidation-reduction potential of the material reach the optimal balance, and the improvement of the photocatalytic performance is facilitated.

The invention prepares a one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material by combining electrostatic spinning with a calcining process. The bismuth molybdate-tungstate solid solution is beneficial to improvement of photocatalytic performance, and separation of photon-generated carriers is further promoted after the bismuth molybdate-tungstate solid solution and nickel oxide form a heterojunction, so that the photocatalytic performance is further improved.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material, a preparation method and application thereof. The one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material is obtained by combining electrostatic spinning with a calcination process, has excellent photocatalytic performance, researches the biotoxicity of a pollutant solution through a mung bean sprouting experiment, shows no obvious inhibition effect on sprouting of mung beans by a solution subjected to photocatalytic degradation, and shows that the photocatalytic material can effectively remove the biotoxicity in the pollutant solution.

Description of terms:

spinning receiving distance: distance of the electrospinning needle to the receiving device.

Room temperature: having a meaning well known in the art, meaning 25. + -. 5 ℃.

The technical scheme of the invention is as follows:

a one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material is characterized in that the microscopic morphology of the one-dimensional nickel oxide/molybdenum bismuth tungstate is a hollow nanotube.

According to the invention, the diameter of the hollow nanotube is 100-500nm, the wall thickness of the nanotube is 50-150nm, and the length is 5-20 μm.

Further, the preparation method of the one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material comprises the following steps:

(1) dissolving ammonium molybdate, ammonium metatungstate, bismuth nitrate and a nickel source in a mixed solution A consisting of absolute ethyl alcohol and N, N-dimethylformamide, adjusting the pH of the solution to be 1.0-4.0, then adding citric acid, and stirring to obtain a nickel oxide/molybdenum bismuth tungstate solution;

(2) adding the nickel oxide/molybdenum bismuth tungstate solution prepared in the step (1) into a mixed solution B consisting of absolute ethyl alcohol and N, N-dimethylformamide dissolved with polyvinylpyrrolidone (PVP), and stirring until the solution is uniformly mixed to obtain nickel oxide/molybdenum bismuth tungstate sol;

(3) performing electrostatic spinning on the nickel oxide/bismuth tungstate sol prepared in the step (2) at room temperature to obtain nickel oxide/bismuth tungstate gel fibers;

(4) and (4) putting the nickel oxide/molybdenum bismuth tungstate gel fibers prepared in the step (3) into a drying oven for drying, and then calcining in an air atmosphere to obtain the nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material.

Preferably according to the invention, the nickel source in step (1) is nickel nitrate hexahydrate or nickel acetate tetrahydrate.

Preferably, according to the invention, the molar ratio of Mo and W in step (1) is 1: (0-1); the molar ratio of Mo to Bi is (0-1): 2; the molar ratio of Bi to Ni is 1: 1; the molar ratio of the nickel source to the citric acid is 1: (2-6).

Preferably, according to the present invention, the volume ratio of the absolute ethyl alcohol to the N, N-dimethylformamide in the step (1) is 1: 1; the molar volume ratio of the nickel source to the mixed solution A is 1: (4-10), unit mmol/mL.

Preferably, according to the invention, in step (1), the pH of the solution is adjusted with nitric acid having a mass concentration of 66% by weight or hydrochloric acid having a mass concentration of 37% by weight or acetic acid having a mass concentration of 99% by weight.

According to the present invention, the volume ratio of the absolute ethanol to the N, N-dimethylformamide in the step (2) is 1: 4; the mass volume ratio of the polyvinylpyrrolidone to the mixed solution B is (0.8-1.0): (10-15) in g/mL.

Preferably, in step (3), the electrostatic spinning has a receiving distance of 15-20cm, a spraying rate of 1.0-1.5mL/h, a voltage of 15-25kV and a relative humidity of 15-30%.

Preferably, according to the invention, the drying temperature in the step (4) is 40-60 ℃, and the drying time is 6-12 h; the calcination temperature is 500-700 ℃, the heating rate is 1-5 ℃/min, and the heat preservation time is 1-2 h.

All chemicals used in the present invention were of analytical grade and were not further processed.

Compared with the prior art, the invention has the following advantages:

1. the invention combines electrostatic spinning and calcining processes to prepare the one-dimensional nickel oxide/molybdenum bismuth tungstate solid solution photocatalytic material. The one-dimensional nano tube has large specific surface area, can provide a large number of active sites, and is beneficial to the transportation and separation of photon-generated carriers, thereby improving the photocatalytic degradation performance.

2. In the nickel oxide/molybdenum bismuth tungstate solid solution, Mo is replaced by W with stronger electronegativity, so that lattice distortion is caused, and separation of photo-generated carriers is promoted; in addition, the bismuth molybdate-tungstate and the nickel oxide form a heterojunction, so that the separation and transmission of photon-generated carriers are further promoted, and the photocatalytic performance is further improved.

3. The cultivation experiment result of the mung bean sprouts shows that the tetracycline solution after photocatalytic degradation does not have obvious inhibition effect on the growth of the mung bean sprouts, and the photocatalytic material disclosed by the invention is proved to be capable of effectively removing the biotoxicity of the tetracycline solution and beneficial to practical application.

4. The preparation method and the process equipment are simple, and the prepared one-dimensional nickel oxide/bismuth molybdate-tungstate solid solution is uniform in appearance, good in continuity and good in cycling stability, so that the production cost is reduced, and the economic benefit is improved.

Drawings

FIG. 1 is an X-ray diffraction (XRD) spectrum of a nickel oxide/bismuth molybdate tungsten solid solution prepared in accordance with the present invention;

FIG. 2 shows NiO/Bi prepared in example 1₂Mo_0.75W_0.25O₆TEM images of solid solutions;

FIG. 3 is a NiO/Bi solution prepared in comparative example 1₂WO₆A TEM image of (B);

FIG. 4 shows NiO/Bi prepared in comparative example 2₂Mo_0.25W_0.75O₆TEM images of solid solutions;

FIG. 5 is a NiO/Bi solution prepared in comparative example 3₂Mo_0.5W_0.5O₆SEM image of solid solution;

FIG. 6 is a NiO/Bi solution prepared in comparative example 4₂MoO₆A TEM image of (B);

FIG. 7 shows NiO/Bi prepared in example 1₂Mo_0.75W_0.25O₆The absorbance curve of the solid solution photocatalytic material for photocatalytic degradation of tetracycline under the irradiation of simulated sunlight;

FIG. 8 is a NiO/Bi solution prepared in comparative example 1₂WO₆The absorbance curve of the photocatalytic material for photocatalytic degradation of tetracycline under simulated sunlight irradiation;

FIG. 9 shows NiO/Bi prepared in comparative example 2₂Mo_0.25W_0.75O₆The absorbance curve of the solid solution photocatalytic material for photocatalytic degradation of tetracycline under the irradiation of simulated sunlight;

FIG. 10 is a NiO/Bi solution prepared in comparative example 3₂Mo_0.5W_0.5O₆The absorbance curve of the solid solution photocatalytic material for photocatalytic degradation of tetracycline under the irradiation of simulated sunlight;

FIG. 11 is a NiO/Bi solution prepared in comparative example 4₂MoO₆The absorbance curve of the photocatalytic material for photocatalytic degradation of tetracycline under simulated sunlight irradiation;

FIG. 12 shows NiO/Bi in application example 1₂Mo_0.75W_0.25O₆、NiO/Bi₂WO₆、NiO/Bi₂Mo_0.25W_0.75O₆、NiO/Bi₂Mo_0.5W_0.5O₆And NiO/Bi₂MoO₆A graph comparing the degradation rate of the photocatalytic material to 10mg/L tetracycline under simulated solar illumination;

FIG. 13 shows NiO/Bi in application example 2₂Mo_0.75W_0.25O₆A degradation efficiency chart of a 10mg/L tetracycline photocatalytic degradation three-cycle experiment by the photocatalytic material under simulated sunlight;

FIG. 14 is an optical photograph showing the growth of mung bean sprouts of application example 3, wherein a is an optical photograph of a culture with clear water for 7 days, b is an optical photograph of a culture with a 10mg/L tetracycline solution for 7 days, and c is an optical photograph of a culture with a photocatalytic degradation solution for 7 days.

Detailed Description

The invention will be further described with reference to specific embodiments, and the advantages and features of the invention will become apparent as the description proceeds. The examples are illustrative only and do not limit the scope of the present invention in any way. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention, and that such changes and modifications may be made without departing from the spirit and scope of the invention.

The raw materials used in the examples are conventional raw materials, and the equipment used is conventional equipment, all of which are commercially available.

The electrostatic spinning device adopts a common electrostatic spinning machine on the market; the propeller is a conventional plastic syringe;

the polyvinylpyrrolidone (PVP) used in the examples was polyvinylpyrrolidone K88-96, having an average molecular weight of 130 ten thousand.

Example 1: one-dimensional NiO/Bi₂Mo_0.75W_0.25O₆Preparation method of solid solution photocatalytic material

The method comprises the following steps:

(1) weighing 0.1mmol of ammonium molybdate, 0.02mmol of ammonium metatungstate, 2mmol of bismuth nitrate and 2mmol of nickel acetate, adding the ammonium molybdate, the ammonium metatungstate, the bismuth nitrate and the nickel acetate into a mixed solution consisting of 5mL of absolute ethyl alcohol and 5mL of N, N-dimethylformamide, adding 1mL of hydrochloric acid with the mass concentration of 37 wt%, adjusting the pH value of the solution to be 1.0-4.0, then adding 1g of citric acid, and stirring to obtain NiO/Bi₂Mo_0.75W_0.25O₆A solution;

(2) 1g of polyvinylpyrrolidone (PVP) was dissolved in a mixed solution composed of 8mL of anhydrous ethanol and 2mL of N, N-dimethylformamide, and then 3mL of NiO/Bi prepared in step (1) was added₂Mo_0.75W_0.25O₆Stirring the solution until the solution is uniformly mixed to obtain NiO/Bi₂Mo_0.75W_0.25O₆Sol;

(3) NiO/Bi prepared in the step (2)₂Mo_0.75W_0.25O₆Pouring the sol into an injector, and carrying out electrostatic spinning at room temperature, wherein the receiving distance of the electrostatic spinning is 20cm, the ejection rate is 1.0mL/h, the voltage is 20kV, and the relative humidity is 15-30%, so as to obtain NiO/Bi₂Mo_0.75W_0.25O₆Gel fibers;

(4) NiO/Bi prepared in the step (3)₂Mo_0.75W_0.25O₆Putting the gel fiber into a drying oven for drying for 12h, then raising the temperature to 610 ℃ at the heating rate of 1 ℃/min in the air atmosphere, and preserving the temperature for 2h to obtain NiO/Bi₂Mo_0.75W_0.25O₆A solid solution photocatalytic material.

The one-dimensional NiO/Bi prepared in this example₂Mo_0.75W_0.25O₆The X-ray diffraction pattern (XRD) of the solid solution photocatalytic material is shown in fig. 1. As can be seen from FIG. 1, NiO/Bi₂Mo_0.75W_0.25O₆NiO and Bi appear in the sample at the same time₂WO₆And Bi₂MoO₆The diffraction peak of (2) proves that the pure-phase NiO/Bi is synthesized₂Mo_0.75W_0.25O₆。

NiO/Bi prepared in this example₂Mo_0.75W_0.25O₆A Transmission Electron Microscope (TEM) of the solid solution is shown in FIG. 2. As can be seen from FIG. 2, NiO/Bi₂Mo_0.75W_0.25O₆The solid solution is in a one-dimensional nanotube shape, the nanotube is uniform and continuous in shape, and the wall thickness of the nanotube is about 100 nm.

Example 2: NiO/Bi₂Mo_0.75W_0.25O₆Preparation method of solid solution photocatalytic material

The method comprises the following steps:

(1) weighing 0.1mmol of ammonium molybdate, 0.02mmol of ammonium metatungstate, 2mmol of bismuth nitrate and 2mmol of nickel acetate, adding the ammonium molybdate, the ammonium metatungstate, the 2mmol of bismuth nitrate and the 2mmol of nickel acetate into a mixed solution consisting of 4mL of absolute ethyl alcohol and 4mL of N, N-dimethylformamide, adding 1mL of nitric acid with the mass concentration of 66 wt%, adjusting the pH value of the solution to be 1.0-4.0, then adding 0.8g of citric acid, and stirring to obtain NiO & ltLi & gtBi₂Mo_0.75W_0.25O₆A solution;

(2) 1g of polyvinylpyrrolidone (PVP) was dissolved in a mixed solution composed of 12mL of anhydrous ethanol and 3mL of N, N-dimethylformamide, and then 3mL of NiO/Bi prepared in step (1) was added₂Mo_0.75W_0.25O₆Stirring the solution until the solution is uniformly mixed to obtain NiO/Bi₂Mo_0.75W_0.25O₆Sol;

(3) NiO/Bi prepared in the step (2)₂Mo_0.75W_0.25O₆Pouring the sol into an injector, and carrying out electrostatic spinning at room temperature, wherein the receiving distance of the electrostatic spinning is 15cm, the ejection rate is 1.5mL/h, the voltage is 15kV, the relative humidity is 15-30%, and NiO/Bi is obtained₂Mo_0.75W_0.25O₆Gel fibers;

(4) NiO/Bi prepared in the step (3)₂Mo_0.75W_0.25O₆Putting the gel fiber into a drying oven for drying for 12h, then raising the temperature to 600 ℃ at the heating rate of 2 ℃/min in the air atmosphere, and preserving the temperature for 1h to obtain NiO/Bi₂Mo_0.75W_0.25O₆A solid solution photocatalytic material.

Example 3: NiO/Bi₂Mo_0.75W_0.25O₆Preparation method of solid solution photocatalytic material

The method comprises the following steps:

(1) weighing 0.1mmol of ammonium molybdate, 0.02mmol of ammonium metatungstate, 2mmol of bismuth nitrate and 2mmol of nickel acetate, adding the ammonium molybdate, the ammonium metatungstate, the bismuth nitrate and the nickel acetate into a mixed solution consisting of 10mL of absolute ethyl alcohol and 10mL of N, N-dimethylformamide, adding 1mL of acetic acid with the mass concentration of 99 wt%, adjusting the pH value of the solution to be 1.0-4.0, then adding 0.5g of citric acid, and stirring to obtain NiO/Bi₂Mo_0.75W_0.25O₆A solution;

(2) 0.8g of polyvinylpyrrolidone (PVP) was dissolved in a mixed solution composed of 8mL of anhydrous ethanol and 2mL of N, N-dimethylformamide, and then 3mL of NiO/Bi prepared in step (1) was added₂Mo_0.75W_0.25O₆Stirring the solution until the solution is uniformly mixedTo obtain NiO/Bi₂Mo_0.75W_0.25O₆Sol;

(3) NiO/Bi prepared in the step (2)₂Mo_0.75W_0.25O₆Pouring the sol into an injector, and carrying out electrostatic spinning at room temperature, wherein the receiving distance of the electrostatic spinning is 20cm, the ejection rate is 1.5mL/h, the voltage is 25kV, the relative humidity is 15-30%, and NiO/Bi is obtained₂Mo_0.75W_0.25O₆Gel fibers;

(4) NiO/Bi prepared in the step (3)₂Mo_0.75W_0.25O₆Putting the gel fiber into a drying oven for drying for 12h, then raising the temperature to 550 ℃ at the heating rate of 2 ℃/min in the air atmosphere, and preserving the temperature for 2h to obtain NiO/Bi₂Mo_0.75W_0.25O₆A solid solution photocatalytic material.

Comparative example 1:

NiO/Bi₂WO₆The preparation method of the photocatalytic material is the same as that of the embodiment 1, except that;

0.083mmol ammonium metatungstate, 2mmol bismuth nitrate and 2mmol nickel acetate are weighed in the step (1).

Comparative example 2:

NiO/Bi₂Mo_0.25W_0.75O₆The preparation method of the solid solution photocatalytic material is the same as that of the example 1, except that;

in the step (1), 0.035mmol of ammonium molybdate, 0.062mmol of ammonium metatungstate, 2mmol of bismuth nitrate and 2mmol of nickel acetate are weighed.

Comparative example 3:

NiO/Bi₂Mo_0.5W_0.5O₆The preparation method of the solid solution photocatalytic material is the same as that of the example 1, except that;

in the step (1), 0.07mmol of ammonium molybdate, 0.042mmol of ammonium metatungstate, 2mmol of bismuth nitrate and 2mmol of nickel acetate are weighed.

Comparative example 4:

NiO/Bi₂MoO₆The preparation method of the photocatalytic material is the same as that of the embodiment 1, except that; in the step (1), the name is0.143mmol of ammonium molybdate, 2mmol of bismuth nitrate and 2mmol of nickel acetate are taken.

NiO/Bi in comparative examples of the invention₂WO₆、NiO/Bi₂Mo_0.25W_0.75O₆、NiO/Bi₂Mo_0.5W_0.5O₆And NiO/Bi₂MoO₆The X-ray diffraction pattern (XRD) of the photocatalytic material is shown in fig. 1. As can be seen from fig. 1, the diffraction peaks of all samples correspond to those of the standard PDF card, which proves that the phase-pure photocatalytic material is synthesized.

NiO/Bi in comparative examples of the invention₂WO₆、NiO/Bi₂Mo_0.25W_0.75O₆And NiO/Bi₂MoO₆The Transmission Electron Micrographs (TEM) of the photocatalytic material are shown in FIG. 3, FIG. 4 and FIG. 6, respectively, and NiO/Bi₂Mo_0.5W_0.5O₆The Scanning Electron Micrograph (SEM) of (a) is shown in FIG. 5. As can be seen from the SEM and TEM images, the photocatalytic materials in all the comparative examples are hollow nanotube structures.

Application example 1:

photocatalytic degradation of tetracyclines

NiO/Bi prepared by the invention₂Mo_0.75W_0.25O₆And NiO/Bi prepared in comparative example 1₂WO₆NiO/Bi prepared in comparative example 2₂Mo_0.25W_0.75O₆NiO/Bi prepared in comparative example 3₂Mo_0.5W_0.5O₆And NiO/Bi prepared according to comparative example 4₂MoO₆The method is applied to a tetracycline photocatalytic degradation experiment, the used simulated light source is a 800W xenon lamp, the concentration of the tetracycline solution is 10mg/L, and the method comprises the following steps:

40mg of NiO/Bi prepared according to the invention₂Mo_0.75W_0.25O₆And 40mg of NiO/Bi prepared in comparative example 1₂WO₆NiO/Bi prepared in comparative example 2₂Mo_0.25W_0.75O₆NiO/Bi prepared in comparative example 3₂Mo_0.5W_0.5O₆And NiO/Bi prepared according to comparative example 4₂MoO₆Are respectively dispersed to 40The method comprises the following steps of (1) adding a 10mg/L tetracycline solution into mL, and then placing the solution in a dark box for stirring and adsorbing for 30min to reach adsorption balance; and then, turning on a xenon lamp simulating a sunlight source, illuminating the solution, taking 4mL of the solution every 30min, centrifuging for 5min at 8000rpm by using a centrifuge, taking supernatant, and testing absorbance by using a UV-2550 spectrophotometer, wherein the detection wavelength is 200-450 nm. And after the reaction is finished, recovering the precipitate, namely completing the recovery of the catalyst.

FIG. 7 shows NiO/Bi prepared in example 1₂Mo_0.75W_0.25O₆The absorbance curve chart of the photocatalytic material for photocatalytic degradation of tetracycline under simulated sunlight is shown in FIGS. 8-11, which are NiO/Bi prepared in comparative example 1₂WO₆NiO/Bi prepared in comparative example 2₂Mo_0.25W_0.75O₆NiO/Bi prepared in comparative example 3₂Mo_0.5W_0.5O₆And NiO/Bi prepared according to comparative example 4₂MoO₆The absorbance curve of the photocatalytic material for photocatalytic degradation of tetracycline in simulated sunlight has a detection wavelength of 200-450 nm. FIG. 12 is a graph showing the comparison of the degradation efficiency of the photocatalytic material in the present application example in the photocatalytic degradation of 10mg/L tetracycline under the irradiation of simulated sunlight.

As can be seen from FIGS. 7-12, the NiO/Bi prepared in example 1 compares with the degradation efficiency of the catalyst in the comparative example₂Mo_0.75W_0.25O₆The photocatalytic degradation efficiency of tetracycline is the highest and reaches 93.4%.

Application example 2:

photocatalytic degradation cycle performance test of tetracycline

NiO/Bi recovered in application example 1₂Mo_0.75W_0.25O₆Dispersing into 40mL of 10mg/L tetracycline solution, placing in a dark box, stirring and adsorbing for 30min to reach adsorption balance; and then, turning on a xenon lamp simulating a sunlight source, illuminating the solution, taking 4mL of the solution every 30min, centrifuging for 5min at 8000rpm by using a centrifuge, taking supernatant, and testing absorbance by using a UV-2550 spectrophotometer, wherein the detection wavelength is 200-450 nm. After the reaction, the precipitate was recovered. This was repeated three times.

FIG. 13 is a NiO/Bi solution prepared in example 1₂Mo_0.75W_0.25O₆The degradation efficiency of the photocatalytic material in a three-cycle experiment for photocatalytic degradation of 10mg/L tetracycline in simulated sunlight is shown in the figure. As can be seen from FIG. 13, the NiO/Bi prepared in example 1₂Mo_0.75W_0.25O₆The first degradation rate of the photocatalytic material is 93.4%, and after three times of cyclic utilization, the degradation efficiency of the photocatalytic material can still reach 90.5%, which proves that NiO/Bi₂Mo_0.75W_0.25O₆Has good circulation stability, can be repeatedly used and greatly reduces the production cost.

Application example 3:

biotoxicity assay for Tetracycline

Respectively using tap water, 10mg/L tetracycline stock solution and NiO/Bi₂Mo_0.75W_0.25O₆And irrigating and cultivating the mung bean sprouts by using the tetracycline solution after photocatalytic degradation. The biological toxicity of the solution is judged by observing the growth condition of the mung bean sprouts.

FIG. 14 is an optical photograph of the mung bean sprouts cultivated in the present application example, from which it can be seen that the mung bean sprouts cultivated in clear water are in good condition and grow vigorously; the growth of the mung bean sprouts cultivated by the tetracycline stock solution of 10mg/L is obviously inhibited; the growth of the mung bean sprouts cultured by the tetracycline solution after photocatalytic degradation is not obviously inhibited, which shows that the photocatalytic material disclosed by the invention not only can be used for photocatalytic degradation of tetracycline, but also can be used for effectively removing the biotoxicity in tetracycline wastewater.