Method for degrading antibiotics using near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst

Abstract

The invention discloses a method for degrading antibiotics by using a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst. The near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst is used to degrade the antibiotics. The transfer path of the photogenerated electron-hole of the Z-type photocatalyst conforms to the Z-type mechanism, which can not only broaden the light response range and promote the improvement of the migration efficiency of the photogenerated carriers, but also protect and utilize the redox ability with more negative conduction band potentials and more positive valence band potentials. The method has the advantages of wide light response range, high photogenerated electron-hole separation efficiency, high photocatalytic activity, strong redox ability, good stability, corrosion resistance, etc. When used for degrading antibiotics, the method can realize efficient degradation of various antibiotic pollutants. The method has the advantages of simple process, convenient operation, low treatment cost, high treatment efficiency, good degradation effect, etc., and is of great significance for effectively purifying antibiotic pollution in water environment.

Description

Technical Field

[0001] The present invention belongs to the technical field of photocatalysis, and relates to a method for degrading antibiotics by using a near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst. Background Art

[0002] Antibiotics are one of the most popular multi-functional drugs. They can be applied not only to disease treatment and infection prevention, but also to promoting the growth of animals and plants. Therefore, antibiotics can be widely seen in various fields such as medicine, agriculture, and animal husbandry. However, a large amount of antibiotics that have not been effectively utilized enter the water environment through soil erosion, animal manure, and wastewater discharge, posing a great threat to the human living environment and physical health. Therefore, effectively removing antibiotics from the water environment has become an urgent problem to be solved currently.

[0003] Photocatalysis technology is considered a promising and sustainable pollutant removal technology. It can degrade and even mineralize pollutants into harmless CO 2 and H 2 O under the excitation of solar energy, which provides a new path for the treatment of antibiotic pollutants. However, currently widely used photocatalysts, such as g-C 3 N 4 (2.7 eV), TiO 2 (~3.2 eV) and ZnO (~3.37 eV), etc., have relatively wide band gaps and can only be activated by visible light or even ultraviolet light. In contrast, infrared light, which accounts for most (53%) of the solar spectrum, is still not utilized. Therefore, actively developing highly efficient and renewable near-infrared light-responsive photocatalysts is of great significance for giving full play to the role of solar energy.

[0004] In order to achieve the near-infrared light response of the photocatalyst, selecting a suitable narrow-bandgap photocatalyst is an ideal method. Among them, bismuth-rich bismuth oxide semiconductors have relatively narrow band gaps (Eg ~1.2 eV) and are one of the strong candidates for preparing near-infrared spectrum-responsive photocatalysts. However, the existing bismuth-rich bismuth oxide monomers still have weak photocatalytic activity in the near-infrared band, and their redox ability is also very weak. At the same time, like many narrow-band semiconductors, bismuth-rich bismuth oxide monomers also have a relatively fast carrier recombination rate, which is not conducive to the effective utilization of photo-generated carriers and has a low photocatalytic degradation efficiency. It is generally believed that the construction of heterojunctions can effectively promote the migration of photo-generated carriers. However, the migration of charge carriers in ordinary type II heterojunctions will lead to a weakening of the reduction ability of photo-generated electrons and the oxidation ability of holes. For example, bismuth-rich bismuth oxide (Bi 4 O 7When forming a heterojunction with carbon nitride, no obvious near-infrared response is observed, and the redox ability of the catalyst becomes weaker, making it difficult to exhibit excellent photocatalytic degradation performance. Additionally, there are no relevant literature reports on the composite of bismuth-rich bismuth oxide and bismuth-rich bismuth iodide oxide, nor are there reports on the composite of Bi 4 O 7 with other bismuth iodide oxides. Furthermore, in the actual research of this application, it is also found that some bismuth-rich bismuth iodide oxides have the defect of unstable chemical properties, which is not conducive to the preparation of a heterojunction catalyst with stable chemical properties, thus making it difficult to be widely applied in the water environment. At the same time, it is also found that ordinary bismuth iodide oxide cannot form a well-contact heterojunction with Bi 4 O 7 Therefore, it is of great significance to construct a new type of photocatalyst with a wide light response range, high photocatalytic activity, strong redox ability, and good stability for improving the wide application of photocatalytic technology in the treatment of antibiotic pollution and promoting the efficient degradation of antibiotics in the water environment. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method for degrading antibiotics using a near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst, which has simple process, convenient operation, low treatment cost, high treatment efficiency, and good degradation effect.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions.

[0007] A method for degrading antibiotics using a near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst, which uses the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst to degrade antibiotics; the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst uses bismuth-rich bismuth oxide as a carrier, and bismuth-rich bismuth iodide oxide is modified on the bismuth-rich bismuth oxide; the mass percentage content of bismuth-rich bismuth iodide oxide in the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst is ≤10%; the chemical formula of the bismuth-rich bismuth oxide is Bi 4 O 7 ; the chemical formula of the bismuth-rich bismuth iodide oxide is Bi 5 O 7 I.

[0008] In the above method, further improved, the mass percentage content of bismuth-rich bismuth iodide oxide particles in the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst is 1% - 8%; the bismuth-rich bismuth oxide is in the form of nano-sheets; the bismuth-rich bismuth iodide oxide is in the form of particles.

[0009] In the above method, further improved, the mass percentage of bismuth-rich bismuth iodide oxide particles in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst is 2% to 4%.

[0010] In the above method, further improved, the preparation method of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst comprises the following steps:

[0011] S1. Mix bismuth-rich bismuth iodide oxide, sodium bismuthate dihydrate and water, ultrasonically disperse, add an alkaline solution, and stir to obtain a mixed solution;

[0012] S2. Hydrothermally treat the mixed solution obtained in step S1 to obtain a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst.

[0013] In the above method, further improved, in step S1, the bismuth-rich bismuth iodide oxide is prepared by the following method:

[0014] (1) Mix a bismuth salt, an iodide salt solution and ethylene glycol, stir, and dry to obtain a precursor reactant;

[0015] (2) Calcinate the precursor reactant obtained in step (1) to obtain bismuth-rich bismuth iodide oxide.

[0016] In the above method, further improved, in step (1), the molar ratio of bismuth ions in the bismuth salt to iodide ions in the iodide salt solution is 1:0.8 to 1.2; the bismuth salt is bismuth nitrate pentahydrate; the iodide salt is potassium iodide.

[0017] In the above method, further improved, in step (2), the heating rate during the calcination is 2 °C / min to 5 °C / min; the calcination temperature is 500 °C to 560 °C; the calcination time is 3 h to 5 h.

[0018] In the above method, further improved, in step S1, the ratio of bismuth-rich bismuth iodide oxide to sodium bismuthate dihydrate is 6.72 mg to 37.2 mg:2.8 mmol; the ultrasonic dispersion time is 40 min to 90 min; the alkaline solution is sodium hydroxide solution and / or potassium hydroxide solution; the stirring time is 0.5 h to 1.5 h; the molar ratio of hydroxide ions to sodium bismuthate dihydrate in the mixed solution is 1:0.1 to 0.3.

[0019] In the above method, further improved, in step S2, the hydrothermal treatment temperature is 160 °C to 200 °C; the hydrothermal treatment time is 12 h to 20 h.

[0020] In the above method, for further improvement, when using a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst to degrade antibiotics in water, the following steps are included: mixing the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst with the antibiotic wastewater, stirring, and performing a photocatalytic reaction under light irradiation to complete the degradation of antibiotics in the water; the addition amount of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst is 0.2 g to 1.0 g of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst added per liter of the antibiotic wastewater.

[0021] In the above method, for further improvement, the antibiotic in the antibiotic wastewater is tetracycline hydrochloride; the initial concentration of the antibiotic in the antibiotic wastewater is 5 mg / L to 30 mg / L.

[0022] In the above method, for further improvement, the stirring time is 1 h; the photocatalytic reaction is carried out under visible light with λ ≥ 420 nm or near-infrared light with λ ≥ 700 nm; the time of the photocatalytic reaction is ≥ 60 min.

[0023] Compared with the prior art, the advantages of the present invention are as follows:

[0024] (1) Aiming at the deficiencies of existing photocatalytic materials, such as poor response to near-infrared light, still not high photocatalytic activity, inhibited redox ability, poor stability, etc., and the resulting defects such as low utilization rate of sunlight, low pollutant treatment efficiency, and poor degradation effect, the present invention creatively proposes a method for degrading antibiotics using a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst. Specifically, the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst is used to degrade antibiotics. Among them, the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst uses bismuth-rich bismuth oxide as a carrier, and bismuth-rich bismuth iodide oxide is modified on the bismuth-rich bismuth oxide. And the mass percentage content of bismuth-rich bismuth iodide oxide in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst is ≤ 10%. The chemical formula of bismuth-rich bismuth oxide is Bi 4 O 7 , and the chemical formula of bismuth-rich bismuth iodide oxide is Bi 5 O 7 I. In the present invention, the bismuth-rich bismuth oxide (Bi 4 O 7 ) and bismuth-rich bismuth iodide oxide (Bi 5 O 7 I) have appropriate Fermi levels and energy band structures. Therefore, Bi 5 O 7 I is modified on Bi 4 O 7A well - contacted Z - type heterojunction can be formed thereon. The formation of this Z - type heterojunction can not only reduce the recombination of photo - generated carriers, but also improve the redox ability of single bismuth - rich bismuth oxide, and can improve the near - infrared light response ability of bismuth - rich bismuth oxide, thereby effectively improving the near - infrared light response ability of the composite material. At the same time, in the Z - type photocatalyst composed of Bi 5 O 7 I modified on Bi 4 O 7 , the empty Bi 4 O 7 (Bi 5+ (6s 0 )) orbital of bismuth - rich bismuth oxide can be used to adjust the energy band structure to form an intermediate energy level, which can not only broaden the light response range of the composite photocatalyst, improve the utilization rate of near - infrared light, but also promote the migration and separation of photo - generated electron - hole pairs. Moreover, the iodide ions in bismuth - rich bismuth iodide oxide (Bi 5 O 7 I) can be hybridized in the p - orbitals, making the composite material have a more positive delocalized valence - band edge, so that more active holes can be provided to oxidize pollutants, that is, the oxidation ability is stronger. In addition, compared with other bismuth - rich bismuth iodide oxides, the Bi 5 O 7 I used in the present invention has better chemical stability. Therefore, modifying Bi 5 O 7 I on Bi 4 O 7 can obtain a composite material with more excellent stability and can show more excellent corrosion resistance. It can be seen that the near - infrared - responsive bismuth - rich bismuth oxide / bismuth - rich bismuth iodide oxide Z - type photocatalyst adopted in the present invention has a photo - generated electron - hole transfer path that conforms to the Z - type mechanism. It can not only broaden the light response range and promote the migration efficiency of photo - generated carriers, but also protect and utilize the redox ability with more negative conduction - band potentials and more positive valence - band potentials. It has the advantages of a wide light response range, high photo - generated electron - hole separation efficiency, high photocatalytic activity, strong redox ability, good stability, and corrosion resistance. It is a new type of composite photocatalyst with excellent performance, high use value, and good application prospects. At the same time, when it is used for degrading antibiotics, it can achieve the efficient degradation of various antibiotic pollutants, and has the advantages of simple process, convenient operation, low treatment cost, high treatment efficiency, and good degradation effect, which is of great significance for effectively purifying the antibiotic pollution in the water environment.

[0025] (2) In the present invention, in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst, granular bismuth-rich bismuth iodide oxide is modified on nano-sheet bismuth-rich bismuth oxide, and the mass percentage content of bismuth-rich bismuth iodide oxide is optimized to be 1% - 8%, which is more conducive to the full contact between bismuth-rich bismuth oxide nano-sheets and bismuth-rich bismuth iodide oxide particles. By increasing the contact area between the two, more heterojunction sites beneficial to charge transfer are established, thereby enabling more excellent photocatalytic performance. This is because when the content of bismuth-rich bismuth iodide oxide particles is too small, a small amount of bismuth-rich bismuth iodide oxide is not sufficient to form a transport channel conducive to charge transfer, and thus it is difficult to achieve the effective separation and migration of photo-generated electron-hole pairs in bismuth-rich bismuth oxide nano-sheets. When the content of bismuth-rich bismuth iodide oxide particles is excessive, it will damage the effective heterojunction cross-section, thereby reducing the photocatalytic activity. In particular, when the mass percentage content of bismuth-rich bismuth iodide oxide particles is 2% - 4%, the obtained near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst exhibits more excellent photocatalytic performance.

[0026] (3) In the present invention, the preparation method of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst has the advantages of simple synthesis method, low raw material cost, less energy consumption, short time consumption, easy control of conditions, etc., is suitable for continuous large-scale batch production, and is convenient for industrial utilization. Brief Description of the Drawings

[0027] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0028] Figure 1 SEM images of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst (3-BBO), bismuth-rich bismuth iodide oxide (BOI), and bismuth-rich bismuth oxide (BO) prepared in Example 1 of the present invention, where a is BOI, b is BO, and c is 3-BBO.

[0029] Figure 2 Photocurrent curves and electrochemical impedance diagrams of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth iodide oxide (BOI), and bismuth-rich bismuth oxide (BO) prepared in Example 1 of the present invention.

[0030] Figure 3 Diffuse reflectance spectra of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-type photocatalyst (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth iodide oxide (Bi 5 O 7 I), and bismuth-rich bismuth oxide (Bi 4 O 7 ) prepared in Example 1 of the present invention.

[0031] Figure 4 For the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth oxyiodide Z-scheme photocatalysts (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth oxyiodide (Bi 5 O 7 I), and bismuth-rich bismuth oxide (Bi 4 O 7 ) in Example 1 of the present invention, it is the relationship diagram of time-degradation efficiency corresponding to the photocatalytic degradation of TC wastewater under visible light irradiation.

[0032] Figure 5 For bismuth-rich bismuth oxyiodide (Bi 5 O 7 I), bismuth-rich bismuth oxide (Bi 4 O 7 ) and the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth oxyiodide Z-scheme photocatalyst (3-BBO) in Example 2 of the present invention, it is the relationship diagram of time-degradation efficiency corresponding to the photocatalytic degradation of TC wastewater under near-infrared light irradiation.

[0033] Figure 6 For the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth oxyiodide Z-scheme photocatalyst (3-BBO) in Example 3 of the present invention, it is the bar chart of photocatalytic performance for three cycles of reaction.

[0034] Figure 7 For the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth oxyiodide Z-scheme photocatalyst (3-BBO) in Example 3 of the present invention, it is the energy band and degradation mechanism diagram.

[0035] Figure 8 For the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth oxyiodide Z-scheme photocatalyst (3-BBO) and bismuth-rich bismuth oxide / graphitic carbon nitride heterojunction catalyst (Bi 4 O 7 / g-C 3 N 4 ) prepared in Example 1 of the present invention, it is the comparison diagram of the degradation effect on tetracycline hydrochloride under the condition of visible light irradiation with λ ≥ 420 nm and under the condition of near-infrared light irradiation with λ ≥ 700 nm. Detailed Embodiments

[0036] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0037] Example 1

[0038] A method for degrading antibiotics using a near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst, specifically, the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst is used to degrade tetracycline hydrochloride (TC) in water under visible light irradiation with λ ≥ 420 nm, including the following steps:

[0039] Weigh 0.025 g of bismuth-rich bismuth iodide oxide (BOI), bismuth-rich bismuth oxide (BO), and near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalysts (1-BBO, 3-BBO, 5-BBO) respectively, and add them to 50 mL of tetracycline hydrochloride (TC) wastewater with a concentration of 10 mg / L. Stir magnetically in the dark for one hour to reach adsorption equilibrium; then turn on the light source (xenon lamp) and irradiate under visible light (λ ≥ 420 nm) for 90 min to complete the degradation of TC in the wastewater.

[0040] In this example, the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) used is based on bismuth-rich bismuth oxide as the carrier, and bismuth-rich bismuth iodide oxide is modified on the bismuth-rich bismuth oxide. Among them, the mass percentage content of bismuth-rich bismuth iodide oxide in the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst is 3%, and the mass percentage content of bismuth-rich bismuth oxide is 97%; the chemical formula of bismuth-rich bismuth oxide is Bi 4 O 7 , which is nanosheet-like; the chemical formula of bismuth-rich bismuth iodide oxide is Bi 5 O 7 I, which is granular with a diameter of 3 μm.

[0041] In this example, the preparation method of the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) includes the following steps:

[0042] (1) Add 4 mmol of bismuth nitrate pentahydrate to 30 mL of ethylene glycol. After ultrasonic treatment for 30 min, gradually add a potassium iodide solution with a mass fraction of 2 wt%. After stirring for 2 h, collect the precipitate, and wash it three times with ultrapure water and ethanol respectively. Dry it at 80 °C for 6 h to obtain an orange-red product. Weigh 2.5 g of the above orange-red product into a 50 mL covered ceramic crucible, transfer the crucible to a muffle furnace, and increase the calcination temperature to 520 °C at a heating rate of 3 °C / min and maintain it for 4 h. After cooling to room temperature, collect the product to obtain bismuth-rich bismuth iodide oxide, which is Bi 5 O 7 I, named BOI.

[0043] (2) Add 20.16 mg of bismuth-rich bismuth iodide oxide prepared in step (1) and 2.8 mmol of sodium bismuthate dihydrate to 25 mL of ultrapure water by ultrasonic wave, and ultrasonicate and stir for 30 min each to form a uniformly dispersed suspension.

[0044] (3) Add 10 mL of a 1.6 M sodium hydroxide solution dropwise to the suspension obtained in step (2), and stir for 30 min to obtain a pre-reaction precursor dispersion.

[0045] (4) Transfer the completely mixed pre-reaction precursor dispersion obtained in step (3) to a 100 mL reaction kettle liner, and place it in an electric heating oven at 180 °C for reaction for 18 h. After the reaction kettle is naturally cooled to room temperature, wash the obtained product three times with ultrapure water and ethanol respectively. Finally, collect the washed product and place it in a blast drying oven at 60 °C for drying overnight to obtain a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst, named 3-BBO.

[0046] In this example, the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (1-BBO) used is basically the same as 3-BBO, except that: the mass percentage content of bismuth-rich bismuth iodide oxide in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (1-BBO) is 1%.

[0047] In this example, the preparation method of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (1-BBO) used is basically the same as that of 3-BBO, except that: in the preparation method of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (1-BBO), the dosage of bismuth-rich bismuth iodide oxide is 6.72 mg.

[0048] In this example, the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (5-BBO) used is basically the same as 3-BBO, except that: the mass percentage content of bismuth-rich bismuth iodide oxide in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (5-BBO) is 5%.

[0049] In this example, the preparation method of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (5-BBO) used is basically the same as that of 3-BBO, except that: in the preparation method of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (5-BBO), the dosage of bismuth-rich bismuth iodide oxide is 33.6 mg.

[0050] In this example, the preparation method of the bismuth-rich bismuth oxide used includes the following steps: Add 2.8 mmol of NaBiO 3 ·2H 2O was added to 25 mL of ultrapure water. After ultrasonic treatment and stirring for 30 min each, a uniformly dispersed suspension was formed. Then, 10 mL of a 1.6 M sodium hydroxide solution was added dropwise to this suspension. After stirring for 30 min, the completely mixed reaction solution was transferred to a 100 mL reaction kettle liner and placed in an electric heating oven at 180 °C for reaction for 18 h. After the reaction kettle was naturally cooled to room temperature, the obtained product was washed three times with ultrapure water and ethanol respectively. Finally, the washed product was collected and placed in a blast drying oven at 60 °C for drying overnight to obtain bismuth-rich bismuth oxide, which is Bi 4 O 7 , named BO.

[0051] Figure 1 SEM images of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO), bismuth-rich bismuth iodide oxide (BOI), and bismuth-rich bismuth oxide (BO) prepared in Example 1 of the present invention. Among them, a is BOI, b is BO, and c is 3-BBO. From Figure 1 a, it can be seen that bismuth-rich bismuth iodide oxide shows microsphere particles composed of many ultrathin nanosheets stacked together, with a diameter of about 3 μm. From Figure 1 b, it can be seen that bismuth-rich bismuth oxide shows a two-dimensional nanosheet morphology with irregular edges. From Figure 1 c, it can be seen that in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO), the collapsed bismuth-rich bismuth iodide oxide particles are attached to the surface of the bismuth-rich bismuth oxide nanosheets.

[0052] Photoelectrochemical detection was carried out on the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalysts (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth iodide oxide (BOI), and bismuth-rich bismuth oxide (BO) prepared in Example 1, and the results are as Figure 2 shown.

[0053] Figure 2 Photocurrent curves and electrochemical impedance diagrams of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalysts (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth iodide oxide (BOI), and bismuth-rich bismuth oxide (BO) prepared in Example 1 of the present invention. Figure 2 Among them, a is the photocurrent curve diagram, and b is the electrochemical impedance diagram. From Figure 2 a, it can be seen that the photocurrent densities of the prepared near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalysts (1-BBO, 3-BBO, and 5-BBO) are significantly higher than those of pure BOI and pure BO, indicating that the formation of heterojunctions is conducive to the separation of photogenerated carriers. At the same time, from Figure 2From the electrochemical impedance spectroscopy (EIS), it can be known that the order of the arc radius of the prepared samples is: BOI > BO > 1-BBO > 5-BBO > 3-BBO, which means that 3-BBO has the smallest charge transfer resistance. The above results indicate that the formation of the heterojunction is beneficial to promoting the separation and migration of photo-generated electrons and holes, and the content of BOI has a great influence on the improvement of carrier separation and migration. 3-BBO has the best photo-generated carrier separation and migration ability.

[0054] Diffuse reflectance spectroscopy was performed on the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalysts (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth iodide oxide (BOI), and bismuth-rich bismuth oxide (BO) prepared in Example 1, and the results are as Figure 3 shown.

[0055] Figure 3 This is the diffuse reflectance spectrum diagram of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalysts (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth iodide oxide (Bi 5 O 7 I), and bismuth-rich bismuth oxide (Bi 4 O 7 ) prepared in Example 1 of the present invention. As Figure 3 can be seen, after the formation of the heterojunction between bismuth-rich bismuth iodide oxide (Bi 5 O 7 I) and bismuth-rich bismuth oxide (Bi 4 O 7 ), the light absorption ability of the obtained composite material in the region of 200 nm - 1200 nm has been significantly improved, which indicates that the introduction of the narrow-bandgap semiconductor BO and the synergistic effect of the formation of the heterojunction endow the composite material with a wide-range and high-intensity light absorption ability, which is very beneficial to improving the photocatalytic performance of the composite material.

[0056] Determination of degradation efficiency: Every 15 minutes, 1 mL of the photocatalytic degradation solution in the reaction vessel was aspirated, filtered with a 0.25 μm filter head, and the filtrate was detected by high-performance liquid chromatography. The results are as Figure 4 shown.

[0057] Figure 4 This is the relationship diagram of time-degradation efficiency corresponding to the photocatalytic degradation of TC wastewater under visible light irradiation by the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalysts (1-BBO, 5-BBO, and 3-BBO), bismuth-rich bismuth iodide oxide (Bi 5 O 7 I), and bismuth-rich bismuth oxide (Bi 4 O 7 ) in Example 1 of the present invention. Figure 4 In it, Ct represents the concentration of TC after degradation, C0 Represents the initial concentration of TC before the photocatalytic reaction.

[0058] From Figure 4 it can be seen that:

[0059] The degradation efficiency of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst (1-BBO) prepared in Example 1 of the present invention for TC is 90.0% after 90 min of reaction under visible light irradiation.

[0060] The degradation efficiency of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst (3-BBO) prepared in Example 1 of the present invention for TC is 94.8% after 90 min of reaction under visible light irradiation.

[0061] The degradation efficiency of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst (5-BBO) prepared in Example 1 of the present invention for TC is 85.7% after 90 min of reaction under visible light irradiation.

[0062] The bismuth-rich iodine bismuth oxide (Bi 5 O 7 I) prepared in Example 1 of the present invention has a degradation efficiency of 58.7% for TC after 90 min of reaction under visible light irradiation.

[0063] The bismuth-rich bismuth oxide (Bi 4 O 7 ) prepared in Example 1 of the present invention has a degradation efficiency of 32.1% for TC after 90 min of reaction under visible light irradiation.

[0064] The above results show that: The near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalysts (1-BBO, 5-BBO and 3-BBO) prepared in Example 1 can all effectively degrade tetracycline hydrochloride (TC) in wastewater. In particular, the degradation rate of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst (3-BBO) for TC can reach the best, and the degradation efficiency for TC is 94.8% after 90 min of reaction under visible light irradiation, and the photocatalytic degradation rate is 0.0315 min -1 , while the degradation rates of pure bismuth-rich iodine bismuth oxide (Bi 5 O 7 I) and pure bismuth-rich bismuth oxide (Bi 4 O 7 ) are only 0.00901 min -1 and 0.00391 min -1. By comparison, it can be seen that compared with pure bismuth-rich bismuth iodide oxide and pure bismuth-rich bismuth oxide, the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst of the present invention exhibits very excellent photocatalytic performance and can achieve efficient degradation of antibiotic pollutants in wastewater. In particular, the degradation rate of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) for TC wastewater is increased by 3.5 times and 8.1 times respectively compared with bismuth-rich bismuth iodide oxide and bismuth-rich bismuth oxide. The main reason for this phenomenon is that a Z-scheme heterojunction with broad spectral absorption is formed in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst of the present invention, which improves the light response ability and promotes the migration and separation of electrons and holes in the semiconductor.

[0065] Example 2

[0066] A method for degrading antibiotics using a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst, specifically, using the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst to degrade tetracycline hydrochloride (TC) in water under the irradiation of near-infrared light with λ ≥ 700 nm, including the following steps:

[0067] Weigh 0.025 g of bismuth-rich bismuth iodide oxide (Bi 5 O 7 I), bismuth-rich bismuth oxide (Bi 4 O 7 ), and near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) prepared in Example 1, and add them to 50 mL of tetracycline hydrochloride (TC) wastewater with a concentration of 10 mg / L respectively, and stir magnetically in the dark for one hour to reach adsorption equilibrium; then turn on the light source (xenon lamp) and carry out photocatalytic reaction for 90 min under the irradiation of near-infrared light (λ ≥ 700 nm) to complete the degradation of TC in the wastewater.

[0068] Determination of degradation efficiency: Every 15 min, suck 1 mL of the photocatalytic degradation solution in the reaction vessel, filter it with a 0.25 μm filter head, and detect the filtrate by high performance liquid chromatography. The results are as Figure 5 shown.

[0069] Figure 5 This is the relationship diagram of time-degradation efficiency corresponding to bismuth-rich bismuth iodide oxide (Bi 5 O 7 I), bismuth-rich bismuth oxide (Bi 4 O 7 ), and near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) during the photocatalytic degradation of TC wastewater under near-infrared light irradiation in Example 2 of the present invention. Figure 5 In which C tRepresents the concentration of degraded TC, C 0 Indicates the initial concentration of TC before the photocatalytic reaction. From Figure 5 It can be seen that:

[0070] The degradation efficiency of TC by the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) prepared in Example 1 of the present invention under near-infrared light irradiation for 90 min is 31.9%.

[0071] The bismuth-rich bismuth iodide oxide (Bi 5 O 7 I) prepared in Example 1 of the present invention does not have photocatalytic degradation ability under near-infrared light irradiation.

[0072] The bismuth-rich bismuth oxide (Bi 4 O 7 ) prepared in Example 1 of the present invention has a degradation efficiency of only 1.3% for TC after reacting under near-infrared light irradiation for 90 min.

[0073] The above results show that: the degradation efficiency of TC by the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) under near-infrared light irradiation for 90 min is 31.9%, and the photocatalytic degradation rate is 0.00395 min -1 , while the degradation rate of pure bismuth-rich bismuth oxide is only 0.000297 min -1 , and pure bismuth-rich bismuth iodide does not respond to near-infrared light and does not have photocatalytic degradation ability under near-infrared light irradiation. By comparison, it can be seen that: compared with pure bismuth-rich bismuth iodide and bismuth-rich bismuth oxide, the degradation rate of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) of the present invention for TC wastewater under near-infrared light irradiation is increased by 13.3 times compared with bismuth-rich bismuth oxide, and there is a substantial improvement compared with bismuth-rich bismuth iodide. The main reason for this phenomenon is that the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst of the present invention forms a Z-scheme heterojunction with broad-spectrum absorption, which promotes light absorption and improves the separation efficiency of electrons and holes in the semiconductor.

[0074] Example 3

[0075] Investigate the corrosion resistance and stability of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst of the present invention during the photocatalytic degradation process, including the following steps:

[0076] (1) Weigh 0.025 g of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide oxide Z-scheme photocatalyst (3-BBO) in Example 1 and add it to 50 mL of TC wastewater with a concentration of 10 mg / L to obtain a reaction system.

[0077] (2) Place the reaction system obtained in step (1) (TC wastewater added with 3-BBO) on a magnetic stirrer and stir it in the dark for 1 h to reach the adsorption equilibrium. Take out 1 mL of the solution to represent the initial solution to be degraded, that is, the solution at the reaction time of 0 min, measure its concentration by high-performance liquid chromatography, and record it as C. 0 .

[0078] (3) Carry out photocatalytic reaction on the remaining solution in step (2) under visible light (visible light with λ ≥ 420 nm). After 90 min of reaction, take out 1 mL of the solution from the reaction system for filtration, and measure the TC concentration in the filtrate by high-performance liquid chromatography, and record it as C.

[0079] (4) Centrifuge and separate the solution after the reaction in step (3), pour out the supernatant, collect the reacted 3-BBO, wash it with ethanol, centrifuge and dry it to obtain the regenerated 3-BBO, weigh it and re-add it to 50 mL of TC wastewater with a concentration of 10 mg / L to form a new reaction system.

[0080] (5) Continue to repeat steps (2) to (4) twice.

[0081] Figure 6 This is a bar chart of the photocatalytic performance of the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst (3-BBO) in Example 3 of the present invention after three cycles of reaction. Figure 6 In it, the degradation efficiency of TC is used as the vertical coordinate and the number of cycles is used as the horizontal coordinate. It can be seen from Figure 6 that after three cycles, the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst (3-BBO) still exhibits high photocatalytic performance, and the degradation efficiency still reaches 86.06% after three cycles. This shows that the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst of the present invention has the advantages of stable photocatalytic performance, strong corrosion resistance, and high degradation efficiency for antibiotic pollutant wastewater. It is a new type of visible light catalyst with good stability, corrosion resistance and high efficiency, and has good practical application prospects.

[0082] Figure 7 This is the energy band and degradation mechanism diagram of the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-scheme photocatalyst (3-BBO) in Example 3 of the present invention. It can be known from Figure 7 that pure Bi 5 O 7 I can only be excited to generate electrons and holes under visible light irradiation. However, due to the low charge separation efficiency and relatively insufficient light utilization ability, the photocatalytic performance of Bi 5 O 7 I is at a relatively low level. When an appropriate amount of Bi 4 O 7After the formation of the 3-BBO composite photocatalyst, under visible light irradiation, the photo-generated electrons on the valence band (VB) of Bi 4 O 7 nanosheets can be excited to the conduction band (CB) or defect energy levels. At the same time, the photo-generated electrons on the VB of Bi 5 O 7 I can also jump to the CB. Subsequently, under the action of the built-in electric field and electrostatic attraction, the electrons in the CB of Bi 5 O 7 I can quickly recombine with the holes in the VB of Bi 4 O 7 , thus promoting the separation of the holes in the VB of Bi 5 O 7 I and the electrons in the CB of Bi 4 O 7 . Under near-infrared light irradiation, Bi 5 O 7 I cannot be excited, and only the photo-generated electrons on the VB of Bi 4 O 7 nanosheets can undergo transitions. At this time, the existence of the heterojunction interface can still promote the migration of photo-generated holes in Bi 4 O 7 and inhibit their recombination with photo-generated electrons. Therefore, the photocatalytic performance of 3-BBO under near-infrared light irradiation is significantly improved compared with that of pure Bi 4 O 7 . In addition, since the CB potential of Bi 4 O 7 is more positive than the standard redox potential of O 2 / ·O 2 - (-0.33 eV), the photo-generated electrons in the 3-BBO system can reduce the adsorbed O 2 to ·O 2 - radicals. At the same time, the VB potential of Bi 5 O 7 I is higher than the redox potential of ·OH / OH-, so the photo-generated holes in the 3-BBO system can oxidize OH- to produce ·OH.

[0083] In this invention, the degradation effect of the bismuth-rich bismuth oxide / graphitic carbon nitride heterojunction catalyst (Bi 4 O 7 / g-C 3 N 4 ) on tetracycline hydrochloride was also investigated. Except for the different catalysts, other conditions were the same as those in Example 1 and Example 2, and the results are as Figure 8 shown.

[0084] Figure 8For the comparison chart of the degradation effects of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-type photocatalyst (3-BBO) and bismuth-rich bismuth oxide / graphite carbon nitride heterojunction catalyst (Bi 4 O 7 / g-C 3 N 4 ) prepared in Example 1 of the present invention under visible light irradiation conditions with λ ≥ 420 nm and under near-infrared light irradiation conditions with λ ≥ 700 nm for tetracycline hydrochloride. Figure 8 In Figure 8 , a is the visible light irradiation condition with λ ≥ 420 nm, and b is the near-infrared light irradiation condition with λ ≥ 700 nm. As can be seen from Figure 8 , the bismuth-rich bismuth oxide / graphite carbon nitride heterojunction catalyst (Bi 4 O 7 / g-C 3 N 4 ) does not have a near-infrared response effect, and its catalytic degradation effect under visible light is significantly inferior to that of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine bismuth oxide Z-type photocatalyst (3-BBO) of the present invention.

[0085] The preparation method of the adopted bismuth-rich bismuth oxide / graphite carbon nitride heterojunction catalyst (Bi 4 O 7 / g-C 3 N 4 ) includes the following steps:

[0086] Add 20.16 mg of g-C3N4 and 2.8 mmol of NaBiO 3 ·2H 2 O to 25 mL of ultrapure water, and after ultrasonic and stirring for 30 min each, a uniformly dispersed suspension is formed. Then, 10 mL of a sodium hydroxide solution with a concentration of 1.6 M is added dropwise to the suspension. After stirring for 30 min, the completely mixed reaction solution is transferred to a 100 mL reaction kettle liner and placed in an electric heating oven at 180 °C for reaction for 18 h. After the reaction kettle is naturally cooled to room temperature, the obtained product is washed three times with ultrapure water and ethanol respectively. Finally, the washed product is collected and placed in a blast drying oven at 60 °C for drying overnight to obtain the bismuth-rich bismuth oxide / graphite carbon nitride heterojunction catalyst, named Bi 4 O 7 / g-C 3 N 4 .

[0087] In addition, the present invention also investigated the degradation effects of different bismuth-rich iodine bismuth oxide-based composite photocatalysts on pollutants, as shown in Table 1.

[0088] As can be seen from Table 1, the existing bismuth-rich iodine bismuth oxide-based composite photocatalysts cannot quickly and thoroughly remove antibiotics in the water environment.

[0089]

[0090] In Table 1, DE (degradation rate) = (1 - equilibrium concentration of pollutant ÷ initial concentration of pollutant) × 100%; RC: reaction rate constant.

[0091] As can be seen from the above results, in the present invention, the near-infrared-responsive bismuth-rich bismuth oxide / bismuth-rich bismuth iodide Z-scheme photocatalyst adopted has a transfer path of photo-generated electrons and holes that conforms to the Z-scheme mechanism. It can not only broaden the light response range and promote the migration efficiency of photo-generated carriers, but also protect and utilize the redox ability with more negative conduction band potentials and more positive valence band potentials. It has the advantages of a wide light response range, high photo-generated electron-hole separation efficiency, high photocatalytic activity, strong redox ability, good stability, and corrosion resistance. It is a novel composite photocatalyst with excellent performance, high use value, and good application prospects. At the same time, when it is used to degrade antibiotics, it can achieve efficient degradation of various antibiotic pollutants, and has the advantages of simple process, convenient operation, low treatment cost, high treatment efficiency, and good degradation effect, which is of great significance for effectively purifying the antibiotic pollution in the water environment.

[0092] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention by using the above-disclosed methods and technical contents, or modify it into an equivalent embodiment with equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change, and modification made to the above embodiments based on the technical essence of the present invention without departing from the technical solution of the present invention still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for degrading antibiotics using a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst, characterized in that: A near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst is used to degrade antibiotics; the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst uses bismuth-rich bismuth oxide as a carrier, and the bismuth-rich bismuth oxide is modified with bismuth-rich iodine oxide; the mass percentage of bismuth-rich iodine oxide in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst is ≤10%; the chemical formula of the bismuth-rich bismuth oxide is Bi4O7; the chemical formula of the bismuth-rich iodine oxide is Bi5O7I; the preparation method of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst comprises the following steps: S1, mixing bismuth-rich iodine bismuth oxide, sodium bismuthate dihydrate and water, ultrasonically dispersing, adding alkaline solution, stirring, and obtaining a mixed solution; S2. The mixed solution obtained in step S1 is subjected to hydrothermal treatment to obtain a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst; the temperature of the hydrothermal treatment is 160° C. to 200° C.; and the time of the hydrothermal treatment is 12 h to 20 h.

2. The method according to claim 1, characterized in that The mass percentage of bismuth-rich iodine oxide particles in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst is 1% to 8%; the bismuth-rich bismuth oxide is in the form of nanosheets; and the bismuth-rich iodine oxide is in the form of particles.

3. The method according to claim 1, characterized in that The mass percentage of bismuth-rich iodine oxide particles in the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst is 2% to 4%.

4. The method according to claim 3, characterized in that In step S1, the bismuth-rich iodine bismuth oxide is prepared by the following method: (1) mixing a bismuth salt, an iodine salt solution and ethylene glycol, stirring, and drying to obtain a precursor reactant; (2) calcining the precursor reactant obtained in step (1) to obtain bismuth-rich iodine bismuth oxide.

5. The method according to claim 4, characterized in that In step (1), the molar ratio of bismuth ions in the bismuth salt to iodide ions in the iodine salt solution is 1:0.8-1.2; the bismuth salt is bismuth nitrate pentahydrate; and the iodine salt is potassium iodide; In step (2), the heating rate during the calcination process is 2°C / min to 5°C / min; the calcination temperature is 500°C to 560°C; and the calcination time is 3h to 5h.

6. The method according to claim 5, characterized in that In step S1, the ratio of bismuth-rich iodine bismuth oxide to sodium bismuth dihydrate is 6.72 mg to 37.2 mg: 2.8 mmol; the ultrasonic dispersion time is 40 min to 90 min; the alkaline solution is sodium hydroxide solution and / or potassium hydroxide solution; the stirring time is 0.5 h to 1.5 h; and the molar ratio of hydroxide ions to sodium bismuth dihydrate in the mixed solution is 1: 0.1 to 0.

3.

7. The method according to any one of claims 1 to 6, characterized in that: The invention adopts a near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst to degrade antibiotics in water, comprising the following steps: mixing the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst with antibiotic wastewater, stirring, and performing a photocatalytic reaction under light conditions to complete the degradation of the antibiotics in the water; the addition amount of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst is 0.2 g to 1.0 g of the near-infrared responsive bismuth-rich bismuth oxide / bismuth-rich iodine oxide Z-type photocatalyst per liter of antibiotic wastewater.

8. The method according to claim 7, characterized in that The antibiotic in the antibiotic wastewater is tetracycline hydrochloride; the initial concentration of the antibiotic in the antibiotic wastewater is 5 mg / L to 30 mg / L.

9. The method according to claim 8, characterized in that The stirring time is 1 hour; the photocatalytic reaction is carried out under visible light with λ ≥ 420 nm or near-infrared light with λ ≥ 700 nm; the photocatalytic reaction time is ≥ 60 minutes.

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