Preparation method of photocatalyst, photocatalyst and application thereof

Abstract

The application belongs to the technical field of resource utilization, and particularly relates to a preparation method of a photocatalyst, the photocatalyst and application thereof. The preparation method of the photocatalyst provided by the application comprises the following steps: 1) mixing plant powder after repairing cadmium contaminated soil, phenolic resin and urea, and then performing calcination, acid washing, alcohol washing, drying to obtain cadmium-containing porous biochar; 2) placing the cadmium-containing porous biochar obtained in the step 1) in copper ion-containing wastewater to perform adsorption, filtering, drying the filter residue to obtain copper and cadmium-containing porous biochar; 3) reacting the copper and cadmium-containing porous biochar obtained in the step 2) with diethylenetriamine pentaacetic acid aqueous solution and thiourea aqueous solution, filtering after the reaction, washing the filter residue, freeze-drying, calcining to obtain copper and cadmium bimetallic porous biochar photocatalyst. The preparation process realizes resource utilization of hyperaccumulation heavy metal contaminated plants and copper ion-containing wastewater; and the obtained photocatalyst can quickly degrade tetracycline.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of resource utilization, and particularly relates to a preparation method of a photocatalyst, the photocatalyst and application thereof. BACKGROUND

[0002] With the acceleration of the national industrialization and urbanization process, heavy metals, as a non-essential element in the body, gradually enrich in the soil, and have become a major problem of soil pollution. Compared with physical and chemical remediation technologies for soil heavy metal pollution, phytoremediation is a low-cost, small environmental disturbance and low risk of secondary pollution heavy metal pollution control measure.

[0003] The phytoremediation technology for soil heavy metal pollution mainly utilizes the physiological characteristics of plants to tolerate and accumulate heavy metals, so as to purify, absorb and fix heavy metals in the soil. However, the transfer and accumulation of heavy metals in hyperaccumulator plants also pose potential threats. If not properly disposed, heavy metal pollutants will return to the soil through plant decay, leaf fall and other ways, causing "secondary pollution".

[0004] The methods for treating hyperaccumulator plants include incineration, composting, pyrolysis, gasification, compression landfill, liquid phase extraction and the like. These technologies treat the remediated plants as hazardous waste or solid waste, which cannot realize resource utilization and easily cause "secondary pollution". At present, the metal in the hyperaccumulator plant obtained by calcining can be used as a catalyst for resource utilization, which can effectively reduce secondary pollution, but the catalytic effect of the metal catalyst needs to be improved, and there is no photocatalyst for efficient and rapid degradation of tetracycline. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to overcome the defects in the prior art that the catalytic effect of the metal catalyst needs to be improved when the metal in the hyperaccumulator plant obtained by calcining is used as a catalyst for resource utilization, and there is no photocatalyst for efficient and rapid degradation of tetracycline, so as to provide a preparation method of a photocatalyst, the photocatalyst and application thereof.

[0006] The present application provides a preparation method of a photocatalyst, which comprises the following steps:

[0007] 1) mixing plant powder after remediation of cadmium contaminated soil with phenolic resin and urea, and calcining, acid washing, alcohol washing and drying to obtain cadmium-containing porous biochar (denoted as Cd / BC);

[0008] 2) placing the cadmium-containing porous biochar obtained in step 1) in copper ion-containing wastewater for adsorption, filtering, and drying the filter residue to obtain copper and cadmium-containing porous biochar (denoted as Cu / Cd / BC);

[0009] 3) the copper-cadmium-containing porous biochar obtained in step 2) is reacted with a diethylenetriamine pentaacetic acid aqueous solution and a thiourea aqueous solution, after the reaction is completed, filtration is performed, the filter residue is washed, freeze-drying is performed, and calcination is performed to obtain a copper-cadmium bimetallic porous biochar photocatalyst (denoted as CuS / CdS / BC / DTPA). The copper-cadmium bimetallic porous biochar photocatalyst prepared is an organic-inorganic hybrid catalyst.

[0010] Preferably, the plants in the plant powder in step 1) are at least one selected from Sedum plumbizincicola, Bidens pilosa and Solanum nigrum;

[0011] Step 1) further comprises a step of grinding and sieving the plants after remediation of cadmium-contaminated soil to form a plant powder;

[0012] The grinding rotation speed is 200-300 rpm, and the grinding time is 10-30 min.

[0013] The present application does not make specific limitations on the grinding method, and ball milling can be selected, and the ball-to-material ratio of ball milling is (5-25):1.

[0014] Optionally, the sieving is sieving through a 100-mesh sieve.

[0015] Optionally, the plants after remediation of cadmium-contaminated soil further comprise the steps of crushing, washing and drying before grinding;

[0016] The present application does not make specific limitations on the crushing of the plants before grinding, and the purpose of convenient cleaning can be achieved, and after crushing, the length of the plants is 2-10 cm, the solvent for washing is water, the drying temperature after washing of the plants after remediation of cadmium-contaminated soil is 40-60℃, and the drying time is 12-24 h.

[0017] Optionally, the mass content of cadmium in the plant powder is 5-20 mg / g 。

[0018] Preferably, the mass ratio of the plant powder, phenolic resin and urea in step 1) is (1-5):1:(1-2).

[0019] In step 1), the calcination temperature is 400-600℃, and the calcination time is 3-5 h; optionally, the heating rate during calcination is 5-10℃ / min.

[0020] The calcination is performed under an oxygen-free condition.

[0021] Preferably, the calcination is performed under a nitrogen atmosphere.

[0022] Optionally, after the calcination in step 1) is completed, natural cooling to room temperature is performed.

[0023] Preferably, the acid washing in step 1) is hydrochloric acid aqueous solution washing, and the number of acid washing is 2-4 times;

[0024] The mass concentration of hydrochloric acid in the hydrochloric acid aqueous solution is 0.1-0.5%;

[0025] The solvent of the alcohol washing is selected from ethanol;

[0026] The drying temperature in step 1) is 40-60℃, and the drying time is 12-24h.

[0027] Preferably, the mass concentration of copper ions in the copper ion-containing wastewater in step 2) is 100-200mg / L;

[0028] The mass ratio of the cadmium-containing porous biochar to copper ions in the copper ion-containing wastewater is (1-10):1;

[0029] The adsorption in step 2) is carried out under stirring, the stirring speed is 100-150rpm, and the adsorption time is 10-30min;

[0030] The filter residue in step 2) further includes a water washing step before drying;

[0031] The drying temperature in step 2) is 40-60℃, and the drying time is 10-12h.

[0032] Preferably, the mass concentration of thiourea in the thiourea aqueous solution in step 3) is 50-80mg / L;

[0033] The mass concentration of diethylenetriamine pentaacetic acid in the diethylenetriamine pentaacetic acid aqueous solution is 50-80mg / L;

[0034] The mass ratio of diethylenetriamine pentaacetic acid in the diethylenetriamine pentaacetic acid aqueous solution to thiourea in the thiourea aqueous solution is 1:(1-5);

[0035] The mass ratio of the copper and cadmium-containing porous biochar to thiourea in the thiourea aqueous solution is 1:(0.0005-0.0025).

[0036] Preferably, the step of the copper and cadmium-containing porous biochar reacting with the diethylenetriamine pentaacetic acid aqueous solution and the thiourea aqueous solution in step 3) includes: after mixing the copper and cadmium-containing porous biochar with the diethylenetriamine pentaacetic acid aqueous solution and the thiourea aqueous solution, first stirring reaction and then heating reaction are carried out in sequence;

[0037] The stirring reaction speed is 100-150rpm, and the stirring reaction time is 1-3h;

[0038] The heating reaction temperature is 150-180℃, and the heating reaction time is 12-18h.

[0039] Preferably, the washing of the residue in step 3) comprises water washing, and then alcohol washing; and the alcohol washing is preferably ethanol washing.

[0040] The freeze-drying temperature is -50±0.1℃, the freeze-drying vacuum degree is 20±0.1Pa, and the freeze-drying time is 24-48h.

[0041] The calcination temperature in step 3) is 300-500℃, and the calcination time is 6-12h.

[0042] Optionally, the heating rate during calcination is 5-10℃ / min. ；

[0043] The calcination is preferably oxygen-free calcination.

[0044] Preferably, the calcination is carried out under a nitrogen atmosphere.

[0045] Optionally, after the calcination in step 3) is completed, the product is naturally cooled to room temperature.

[0046] The application provides a photocatalyst prepared by the above-mentioned method for preparing a photocatalyst.

[0047] The application also provides application of the photocatalyst prepared by the above-mentioned method for preparing a photocatalyst in degradation of tetracycline.

[0048] The technical scheme of the application has the following advantages:

[0049] 1. The preparation method of the photocatalyst provided by the present invention includes the following steps: 1) Plant powder after remediation of cadmium-contaminated soil is mixed with phenolic resin and urea and calcined, acid washed, alcohol washed, and dried to obtain cadmium-containing porous biochar; 2) The cadmium-containing porous biochar obtained in step 1) is placed in copper-containing wastewater for adsorption, filtered, and the filter residue is dried to obtain copper-cadmium-containing porous biochar; 3) The copper-cadmium-containing porous biochar obtained in step 2) is reacted with diethylenetriaminepentaacetic acid aqueous solution and thiourea aqueous solution. After the reaction is completed, the mixture is filtered, the filter residue is washed, freeze-dried, and calcined to obtain copper-cadmium bimetallic porous biochar photocatalyst. This invention utilizes plants rich in heavy metals as raw materials, combined with phenolic resin and urea, to prepare porous biochar through calcination. During calcination, the urea generates gas that creates more dense channels within the porous biochar. Phenolic resin continuously fills these newly formed channels during calcination, supporting and protecting the pore structure and preventing collapse. After acid and alcohol washing to remove the phenolic resin, a porous biochar with a complete and dense pore structure is finally formed. This porous biochar is then used to adsorb heavy metal ions from wastewater and react with diethylenetriaminepentaacetic acid aqueous solution and thiourea aqueous solution to prepare an organic-inorganic hybrid porous biochar-supported bimetallic composite photocatalyst. In the reaction process, diethylenetriaminepentaacetic acid (DITA) aqueous solution interacts with thiourea aqueous solution to synergistically form CdS and CuS. DITA participates in controlling the structural morphology of CdS and CuS formation, improving the catalytic activity of the product photocatalyst, and simultaneously promoting charge transfer during the photocatalytic process and preventing photocorrosion. The preparation process of this photocatalyst not only achieves the harmless treatment and resource utilization of plants hyperaccumulating heavy metal pollution, but also realizes the resource utilization of copper-containing wastewater. Furthermore, the obtained photocatalyst exhibits high photoresponsive catalytic activity and can rapidly degrade tetracycline under light conditions, providing a new approach for the resource utilization of plants enriched with heavy metals.

[0050] 2. The photocatalyst preparation method provided by the present invention has the advantages of simple process flow, environmental protection and high efficiency, and low cost. Attached Figure Description

[0051] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0052] Figure 1 The graph shows the change in the concentration ratio of tetracycline when the photocatalysts prepared in Examples 1-3 and Comparative Examples 1-5 degrade tetracycline. Detailed Implementation

[0053] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0054] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0055] Example 1

[0056] This embodiment provides a method for preparing a photocatalyst, comprising the following steps:

[0057] 1) The Sedum aizoon, which was used to remediate cadmium-contaminated soil, was crushed to a length of 2 cm, washed with water, and dried at 40°C for 24 h. It was then ball-milled for 30 min at a ball-to-material ratio of 10:1 and a rotation speed of 300 rpm. The resulting plant powder was passed through a 100-mesh sieve and contained cadmium at a mass content of 10 mg / g. The plant powder, phenolic resin, and urea were mixed at a mass ratio of 1:1:1 and calcined at 600°C for 3 h under nitrogen at a heating rate of 10°C / min. The mixture was then allowed to cool naturally to room temperature, washed three times with a 0.2% dilute hydrochloric acid solution, and then washed with ethanol. Finally, it was dried at 40°C for 12 h to obtain cadmium-containing porous biochar (Cd / BC).

[0058] 2) Place 1g of the cadmium-containing porous biochar obtained in step 1) into 1L of copper ion-containing wastewater with a copper ion concentration of 200mg / L for adsorption. The adsorption time is 30min, and the stirring speed during adsorption is 110rpm. After centrifugation and filtration, the filter residue is washed with water and dried at 40℃ for 12h to obtain copper-cadmium-containing porous biochar Cu / Cd / BC.

[0059] 3) 1g of copper-cadmium porous biochar obtained in step 2), 10mL of 50mg / L DTPA aqueous solution, and 30mL of 50mg / L thiourea aqueous solution were stirred and reacted for 1h at a stirring speed of 110rpm. The resulting suspension was transferred to a polytetrafluoroethylene-lined autoclave and heated to react at a temperature of 180℃ for 12h. After the reaction was completed, the mixture was filtered, and the filter residue was washed with water and then with ethanol. The product was then freeze-dried at a temperature of -50℃, a vacuum of 20Pa, and a freezing time of 48h. The freeze-dried product was then calcined at 500℃ for 5h under a nitrogen atmosphere at a rate of 10℃ / min. After natural cooling to room temperature, the copper-cadmium bimetallic porous biochar photocatalyst CuS / CdS / BC / DTPA was obtained.

[0060] Example 2

[0061] This embodiment provides a method for preparing a photocatalyst, comprising the following steps:

[0062] 1) After remediating cadmium-contaminated soil, Bidens trifoliata was crushed to a length of 5 cm, washed with water, and dried at 40℃ for 24 h. It was then ball-milled for 10 min at a ball-to-material ratio of 5:1 and a rotation speed of 200 rpm. The resulting plant powder was passed through a 100-mesh sieve and contained cadmium at a mass content of 5 mg / g. The plant powder, phenolic resin, and urea were mixed at a mass ratio of 1:1:1 and calcined at 400℃ for 3 h under nitrogen at a heating rate of 10℃ / min. The mixture was then naturally cooled to room temperature, washed twice with a 0.1% dilute hydrochloric acid solution, and then washed with ethanol. Finally, it was dried at 40℃ for 12 h to obtain cadmium-containing porous biochar (Cd / BC).

[0063] 2) Place 1g of the cadmium-containing porous biochar obtained in step 1) into 5L of copper ion-containing wastewater with a copper ion concentration of 200mg / L for adsorption. The adsorption time is 30min, and the stirring speed during adsorption is 100rpm. After centrifugation and filtration, the filter residue is washed with water and dried at 40℃ for 10h to obtain copper-cadmium-containing porous biochar Cu / Cd / BC.

[0064] 3) 1g of copper-cadmium porous biochar obtained in step 2), 10mL of 50mg / L DTPA aqueous solution, and 10mL of 50mg / L thiourea aqueous solution were stirred and reacted for 1h at a stirring speed of 100rpm. The resulting suspension was transferred to a polytetrafluoroethylene-lined autoclave and heated to react at a temperature of 150℃ for 12h. After the reaction was completed, the mixture was filtered, and the filter residue was washed with water and then with ethanol. The product was then freeze-dried at a temperature of -50℃, a vacuum of 20Pa, and a freezing time of 48h. The freeze-dried product was then calcined at 300℃ for 6h under a nitrogen atmosphere at a rate of 10℃ / min. After natural cooling to room temperature, the copper-cadmium bimetallic porous biochar photocatalyst CuS / CdS / BC / DTPA was obtained.

[0065] Example 3

[0066] This embodiment provides a method for preparing a photocatalyst, comprising the following steps:

[0067] 1) The black nightshade after remediation of cadmium-contaminated soil was crushed into 5cm lengths, washed with water, dried at 40℃ for 24h, ball-milled for 30min at a ball-to-material ratio of 25:1 and a rotation speed of 300rpm, and passed through a 100-mesh sieve to obtain plant powder. The cadmium content in the plant powder was 20mg / g. The plant powder, phenolic resin and urea were mixed at a mass ratio of 1:1:1 and calcined at 600℃ for 5h under nitrogen at a heating rate of 10℃ / min. After natural cooling to room temperature, the mixture was washed four times with a 0.5% dilute hydrochloric acid solution and then washed with ethanol. After drying at 60℃ for 24h, cadmium-containing porous biochar Cd / BC was obtained.

[0068] 2) Place 2g of the cadmium-containing porous biochar obtained in step 1) into 1L of copper ion-containing wastewater with a copper ion concentration of 200mg / L for adsorption. The adsorption time is 30min, and the stirring speed during adsorption is 150rpm. After centrifugation and filtration, the filter residue is washed with water and dried at 60℃ for 12h to obtain copper-cadmium-containing porous biochar Cu / Cd / BC.

[0069] 3) 1g of copper-cadmium porous biochar obtained in step 2), 10mL of 50mg / L DTPA aqueous solution, and 50mL of 50mg / L thiourea aqueous solution were stirred and reacted for 1h at a stirring speed of 150rpm. The resulting suspension was transferred to a polytetrafluoroethylene-lined autoclave and heated to react at a temperature of 180℃ for 18h. After the reaction was completed, the mixture was filtered, and the filter residue was washed with water and then with ethanol. The product was then freeze-dried at a temperature of -50℃, a vacuum of 20Pa, and a time of 48h. The freeze-dried product was then calcined at 500℃ for 12h under a nitrogen atmosphere at a rate of 10℃ / min. After natural cooling to room temperature, the copper-cadmium bimetallic porous biochar photocatalyst CuS / CdS / BC / DTPA was obtained.

[0070] Comparative Example 1

[0071] This comparative example provides a method for preparing a photocatalyst, which differs from Example 1 in that phenolic resin and urea are not added in step 1).

[0072] Comparative Example 2

[0073] This comparative example provides a method for preparing a photocatalyst, which differs from Example 1 in that, in step 1), plant powder and urea are mixed at a mass ratio of 1:2, and no phenolic resin is added.

[0074] Comparative Example 3

[0075] This comparative example provides a method for preparing a photocatalyst, which differs from Example 1 in that, in step 1), plant powder and phenolic resin are mixed at a mass ratio of 1:2, and urea is not added.

[0076] Comparative Example 4

[0077] This comparative example provides a method for preparing a photocatalyst. The difference between this method and Example 1 is that in step 3), 1g of copper-cadmium porous biochar obtained in step 2) and 40mL of 50mg / L thiourea aqueous solution are stirred and reacted without adding DTPA aqueous solution, and other conditions remain unchanged, to obtain the copper-cadmium bimetallic porous biochar photocatalyst CuS / CdS / BC.

[0078] Comparative Example 5

[0079] This comparative example provides a method for preparing a photocatalyst. The difference between this method and Example 1 is that in step 3), 1g of copper-cadmium porous biochar obtained in step 2) and 40mL of 50mg / L DTPA aqueous solution are stirred and reacted without adding thiourea aqueous solution, and other conditions remain unchanged, to obtain a copper-cadmium bimetallic porous biochar photocatalyst Cu / Cd / BC / DTPA.

[0080] Test case

[0081] Using a 300W xenon lamp to simulate sunlight, the photocatalytic degradation performance of tetracycline by the CuS / CdS / BC / DTPA photocatalysts prepared in Examples 1-3 and Comparative Examples 1-5 was measured. Before illumination, the photocatalyst and tetracycline were stirred at 100 rpm for 30 min in the dark to ensure adsorption equilibrium was reached and the tetracycline concentration no longer changed. Stirring was continued at 100 rpm, and timing began after the xenon lamp was turned on. Every 5 min, 1 mL of sample was taken from the reactor, and the tetracycline concentration (denoted as C) was measured at 356 nm using a UV-Vis spectrophotometer. The initial tetracycline concentration was denoted as C0. The degradation efficiency of the photocatalyst for tetracycline was determined based on the concentration ratio C / C0. The test results are as follows. Figure 1 As shown.

[0082] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a photocatalyst, characterized in that, Includes the following steps: 1) Plant powder after remediation of cadmium-contaminated soil is mixed with phenolic resin and urea, calcined, acid-washed, alcohol-washed, and dried to obtain cadmium-containing porous biochar. 2) The cadmium-containing porous biochar obtained in step 1) is placed in copper-containing wastewater for adsorption, filtered, and the filter residue is dried to obtain copper-cadmium-containing porous biochar. 3) The copper-cadmium porous biochar obtained in step 2) is reacted with diethylenetriaminepentaacetic acid aqueous solution and thiourea aqueous solution. After the reaction is completed, the mixture is filtered, the filter residue is washed, freeze-dried, and calcined to obtain copper-cadmium bimetallic porous biochar photocatalyst. The plant in the plant powder mentioned in step 1) is selected from at least one of Sedum sarmentosum, Bidens trifoliata, and Solanum nigrum; Step 1) also includes grinding and sieving the plants after remediation of cadmium-contaminated soil to form plant powder; The grinding speed is 200-300 rpm, and the grinding time is 10-30 min; The mass ratio of plant powder, phenolic resin and urea in step 1) is (1-5):1:(1-2); The calcination temperature in step 1) is 400-600℃, and the calcination time is 3-5 h; The calcination described in step 1) is carried out under anaerobic conditions.

2. The method for preparing the photocatalyst according to claim 1, characterized in that, The calcination described in step 1) is carried out under a nitrogen atmosphere.

3. The method for preparing the photocatalyst according to claim 1, characterized in that, Step 1) The pickling is performed by washing with hydrochloric acid aqueous solution, and the number of pickling cycles is 2-4. The hydrochloric acid in the aqueous solution has a mass concentration of 0.1-0.5%. The solvent for the alcohol washing is selected from ethanol; The drying temperature in step 1) is 40-60℃, and the drying time is 12-24h.

4. The method for preparing the photocatalyst according to claim 1, characterized in that, The mass concentration of copper ions in the copper-containing wastewater mentioned in step 2) is 100-200 mg / L; The mass ratio of the cadmium-containing porous biochar to the copper ions in the copper-containing wastewater is (1-10):1; The adsorption described in step 2) is carried out under stirring at a speed of 100-150 rpm for a time of 10-30 min. Step 2) further includes a water washing step before the filter residue is dried; The drying temperature in step 2) is 40-60℃, and the drying time is 10-12 h.

5. The method for preparing the photocatalyst according to claim 1, characterized in that, The thiourea concentration in the thiourea aqueous solution described in step 3) is 50-80 mg / L; The mass concentration of diethylenetriaminepentaacetic acid in the aqueous solution of diethylenetriaminepentaacetic acid is 50-80 mg / L; The mass ratio of diethylenetriaminepentaacetic acid in the aqueous solution to thiourea in the aqueous solution is 1:(1-5). The mass ratio of the copper-cadmium porous biochar to the mass ratio of thiourea in the thiourea aqueous solution is 1:(0.0005-0.0025).

6. The method for preparing the photocatalyst according to claim 1, characterized in that, The step 3) of reacting copper-cadmium porous biochar with diethylenetriaminepentaacetic acid aqueous solution and thiourea aqueous solution includes: mixing copper-cadmium porous biochar with diethylenetriaminepentaacetic acid aqueous solution and thiourea aqueous solution, stirring the mixture first, and then heating it to react. The stirring speed is 100-150 rpm, and the stirring time is 1-3 hours. The heating reaction temperature is 150-180℃, and the heating reaction time is 12-18 h.

7. The method for preparing the photocatalyst according to any one of claims 1-6, characterized in that, The filter residue washing described in step 3) includes water washing followed by alcohol washing; The freeze-drying temperature is -50±0.1℃, the freeze-drying vacuum degree is 20±0.1 Pa, and the freeze-drying time is 24-48 h; In step 3), the calcination temperature is 300-500℃ and the calcination time is 6-12h; The calcination described in step 3) is anaerobic calcination.

8. The method for preparing the photocatalyst according to claim 7, characterized in that, The calcination described in step 3) is carried out under a nitrogen atmosphere.

9. A photocatalyst, characterized in that, The photocatalyst is prepared by the method for preparing the photocatalyst according to any one of claims 1-8.

10. The application of the photocatalyst prepared by the method of any one of claims 1-8 in the degradation of tetracycline.

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