Preparation method and application of tungsten anchored g-C3N4 photocatalyst

Abstract

The invention relates to the technical field of advanced oxidation, and discloses a preparation method and application of a tungsten anchored g-C3N4 photocatalyst. The preparation method of the tungsten-anchored g-C3N4 photocatalyst comprises the following steps: preparing a yellow g-C3N4 block by taking melamine as a raw material, mixing and grinding the g-C3N4 block, NaOH and WCl6 under an infrared lamp, then adding ultrapure water, performing ultrasonic treatment, drying, and calcining in a nitrogen atmosphere to obtain the tungsten-anchored g-C3N4 photocatalyst. The prepared tungsten anchored g-C3N4 photocatalyst shows efficient performance of photoactivated peroxymonosulfate for degrading ofloxacin, meanwhile, the preparation process is safe, simple, convenient and efficient, and the tungsten anchored g-C3N4 photocatalyst has potential environment purification application prospects.

Description

Technical Field

[0001] This invention relates to the field of advanced oxidation technology, specifically to a method for preparing a tungsten-anchored g-C3N4 photocatalyst and its application. Background Technology

[0002] Ofloxacin, a third-generation fluoroquinolone antibiotic, is widely used in human medicine, veterinary clinics, and animal husbandry due to its broad-spectrum antibacterial activity and high bioavailability. However, due to its poor biodegradability, ofloxacin cannot be effectively removed in conventional wastewater treatment plants, leading to its frequent detection in various environmental media such as water, soil, and even sediments.

[0003] Persulfate advanced oxidation technology (PAO) is a rapidly developing novel pollutant treatment technology in recent years. Its core principle involves the decomposition of PAO into highly reactive species with strong oxidizing capabilities, such as sulfate radicals, hydroxyl radicals, and singlet oxygen, through energy input or catalyst activation. These reactive species can rapidly attack and degrade organic pollutants, even achieving complete mineralization. Therefore, sulfate radical-based PAO processes have attracted significant attention due to their high oxidation potential, wide pH applicability, and strong resistance to interference in complex water bodies. PAO, with its high stability and safe transportation, has become a promising oxidant precursor.

[0004] Graphitic carbon nitride has shown great potential in the field of photocatalysis due to its unique two-dimensional layered structure, suitable band structure and visible light response. Its preparation is simple, low cost and stable physicochemical properties, and it is considered to be one of the ideal substrate materials for constructing photoactivated PMS systems.

[0005] Traditional g-C3N4 has a large and dense block structure with insufficient exposure of active sites, which severely limits its contact efficiency with PMS and pollutant molecules. Pure g-C3N4 has limited activation ability for PMS and often needs to be combined with other highly active components.

[0006] Tungsten, as a non-precious metal, has advantages such as multiple valence states, low biotoxicity, and low leaching tendency. Previous studies have introduced tungsten into g-C3N4 to prepare catalysts for degrading pollutants, but the degradation effect still needs to be improved. Therefore, it is necessary to provide an enhanced method for photoactivated persulfate degradation of ofloxacin, which can simultaneously improve the degradation rate and efficiency of ofloxacin, thereby comprehensively improving the effect of persulfate degradation of ofloxacin. Summary of the Invention

[0007] To address the problems existing in the prior art, one objective of this invention is to provide a method for preparing a tungsten-anchored g-C3N4 photocatalyst, comprising the following steps: (1) Melamine was calcined to obtain yellow g-C3N4 blocks.

[0008] (2) Yellow g-C3N4 block, NaOH and WCl6 are mixed and ground under infrared lamp, then water is added and ultrasonic is performed. After ultrasonication, the powder is dried, and the powder obtained by drying is calcined. The calcined product is washed and dried to obtain tungsten-anchored g-C3N4 photocatalyst.

[0009] Preferably, the calcination conditions in step (1) are to heat to 500-550°C at a heating rate of 5-10°C / min in an air atmosphere and calcinate for 1.5-3 hours.

[0010] Preferably, in step (2), the mass ratio of yellow g-C3N4 block, NaOH and WCl6 is yellow g-C3N4 block:NaOH:WCl6=1:(0.05~0.1):(0.03~0.09).

[0011] Preferably, the calcination conditions in step (2) are to heat to 500-550°C at a heating rate of 5-10°C / min under a nitrogen atmosphere and calcinate for 3-4 hours.

[0012] Preferably, the washing method described in step (2) is to wash the sample with hydrochloric acid solution at least once, and then wash the sample with ultrapure water at least three times.

[0013] The second objective of this invention is to provide an application of tungsten-anchored g-C3N4 photocatalyst in the degradation of ofloxacin by activating persulfate.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention utilizes the redox cycle between the various valences of tungsten to effectively activate PMS (persulfate), thereby generating active species such as sulfate radicals and hydroxyl radicals, and increasing the reaction rate.

[0015] (2) The present invention prepared a tungsten-anchored g-C3N4 photocatalyst by pyrolysis and added NaOH for alkaline treatment, so that tungsten can be precisely anchored on g-C3N4, thereby regulating the morphology and structure of g-C3N4, introducing active functional groups, optimizing electronic structure and improving the dispersion and binding of tungsten, forming nanosheets with more pores, which can provide efficient heterogeneous catalytic sites for persulfate activation, and improve the degradation effect of persulfate on ofloxacin. This efficient coupling of "photocatalysis" and "persulfate activation" can continuously generate a variety of highly active species such as sulfate radicals and hydroxyl radicals. Compared with "photocatalysis" alone, the degradation performance of ofloxacin is significantly improved. Through the method of the present invention, 98.7% of ofloxacin can be degraded in about 10 minutes.

[0016] (3) The catalyst of this invention remained stable in five cycles of testing, demonstrating excellent stability.

[0017] (4) The present invention has excellent degradation performance of ofloxacin in a variety of actual water bodies. Attached Figure Description

[0018] Figure 1 The XRD diffraction patterns are those of the catalysts prepared in Examples 1-4 and Comparative Example 1.

[0019] Figure 2 These are SEM images of the catalysts prepared in Example 1 and Comparative Example 1 of the present invention, as well as TEM and EDS images of the catalyst prepared in Example 1.

[0020] Figure 3 This is the UV-DRS image of the catalysts prepared in Example 1 and Comparative Example 1 of this invention.

[0021] Figure 4 This is a PL diagram of the catalysts prepared in Example 1 and Comparative Example 1 of the present invention.

[0022] Figure 5 The graph shows the photocatalytic degradation performance of ofloxacin by the catalysts prepared in Example 1 and Comparative Example 1.

[0023] Figure 6 The graph shows the performance of the catalyst prepared in Example 1 in degrading ofofloxacin in different water bodies.

[0024] Figure 7 The graphs show the photo-activated persulfate degradation performance of ofloxacin by the catalysts prepared in Examples 1-4 and Comparative Example 1.

[0025] Figure 8 The graph shows the photocatalytic degradation performance of ofloxacin by the catalysts prepared in Example 1 and Comparative Example 2.

[0026] Figure 9 The graph shows the photocatalytic degradation performance of ofloxacin by the catalysts prepared in Examples 1, 5, 6 and Comparative Example 3.

[0027] Figure 10 The stability test diagram is prepared in Example 1. Detailed Implementation

[0028] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0029] Unless otherwise specified, all reagents used in this invention are commercially available analytical grade reagents.

[0030] Example 1 The preparation method of a tungsten-anchored g-C3N4 catalyst is as follows: (1) Place 10g of melamine in a muffle furnace and heat it to 550℃ at a heating rate of 10℃ / min in air atmosphere. Calcine for 2h to obtain yellow g-C3N4 block.

[0031] (2) Mix and grind 100mg of yellow g-C3N4 block, 10mg of NaOH and 5mg of WCl6 under an infrared lamp, then add to 30mL of ultrapure water, sonicate for 30min, dry in an oven at 60℃ and collect the powder.

[0032] (3) The powder obtained in (2) was placed in a tube furnace and heated to 550°C at a heating rate of 10°C / min under a nitrogen atmosphere. The calcined product I was obtained after calcination for 4 hours. The calcined product I was washed once with 1 mmol / L hydrochloric acid solution, then washed three times with ultrapure water, and dried in an oven at 60°C. The tungsten-anchored g-C3N4 photocatalyst was collected.

[0033] The catalyst prepared in this embodiment is designated as WCN-5.

[0034] Example 2 The preparation method of a tungsten-anchored g-C3N4 catalyst is as follows: (1) Place 10g of melamine in a muffle furnace and heat it to 500℃ in air atmosphere at a heating rate of 5℃ / min. Calcine for 3h to obtain yellow g-C3N4 block.

[0035] (2) Mix and grind 100mg of yellow g-C3N4 block, 10mg of NaOH and 3mg of WCl6 under an infrared lamp, then add it to 30mL of ultrapure water, sonicate for 30min, dry in an oven at 60℃ and collect the powder.

[0036] (3) The powder obtained in (2) was placed in a tube furnace and heated to 500°C at a heating rate of 5°C / min under a nitrogen atmosphere. The calcined product I was obtained after calcination for 3 hours. The calcined product I was washed once with 1 mmol / L hydrochloric acid solution, then washed three times with ultrapure water, and dried in an oven at 60°C. The tungsten-anchored g-C3N4 photocatalyst was collected.

[0037] The catalyst prepared in this embodiment is designated as WCN-3.

[0038] Example 3 This embodiment uses the same method as Example 1 to prepare the W-C3N4 catalyst, except that the amount of WCl6 added in this embodiment is 7 mg.

[0039] The catalyst prepared in this embodiment is designated as WCN-7.

[0040] Example 4 This embodiment uses the same method as Example 1 to prepare the W-C3N4 catalyst, except that the amount of WCl6 added in this embodiment is 9 mg.

[0041] The catalyst prepared in this embodiment is designated as WCN-9.

[0042] Example 5 The preparation method of a tungsten-anchored g-C3N4 catalyst is as follows: (1) Place 10g of melamine in a muffle furnace and heat it to 550℃ at a heating rate of 10℃ / min in air atmosphere. Calcine for 1.5h to obtain yellow g-C3N4 block.

[0043] (2) Mix and grind 100mg of yellow g-C3N4 block, 5mg of NaOH and 5mg of WCl6 under an infrared lamp, then add to 30mL of ultrapure water, sonicate for 30min, dry in an oven at 60℃ and collect the powder.

[0044] (3) The powder obtained in (2) was placed in a tube furnace and heated to 550°C at a heating rate of 10°C / min under a nitrogen atmosphere. The calcined product I was obtained after calcination for 4 hours. The calcined product I was washed once with 1 mmol / L hydrochloric acid solution, then washed three times with ultrapure water, and dried in an oven at 60°C. The tungsten-anchored g-C3N4 photocatalyst was collected.

[0045] The catalyst prepared in this embodiment is designated as MWCN-5.

[0046] Example 6 This embodiment uses the same method as Example 1 to prepare the W-C3N4 catalyst, except that the amount of NaOH added in this embodiment is 15 mg.

[0047] The catalyst prepared in this embodiment is designated as MWCN-15.

[0048] Comparative Example 1 The catalyst in this comparative example was prepared using the same method as in Example 1, except that NaOH and WCl6 were not added.

[0049] The catalyst prepared in this embodiment is denoted as CN.

[0050] Comparative Example 2 The catalyst in this comparative example was prepared using the same method as in Example 1, except that the tungsten source used in this comparative example was WO3.

[0051] The catalyst prepared in this embodiment is denoted as WOCN.

[0052] Comparative Example 3 The catalyst in this comparative example was prepared using the same method as in Example 1, except that NaOH was not used.

[0053] The catalyst prepared in this embodiment is denoted as MWCN-0.

[0054] Figure 1 The X-ray diffraction patterns of the catalysts prepared in Examples 1-4 and Comparative Example 1 of this invention are shown in the figures. It can be seen from the figures that the characteristic peaks of W-C3N4 and CN are consistent with the standard card. No extra diffraction peaks appear in the figures, which proves that the W-C3N4 catalyst was successfully prepared in Examples 1-4 and the CN catalyst was successfully prepared in Comparative Example 1.

[0055] Figure 2 These are SEM images of the catalysts prepared in Comparative Example 1 and Example 1 of this invention. Figure 2 a, b), and TEM images of the catalyst prepared in Example 1 ( Figure 2 c) and EDS plot ( Figure 2 d) As can be seen from the figure, the introduction of tungsten successfully modulates the morphology of C3N4, transforming it from a dense bulk into a porous nanostructure. Its porous nanosheet structure suggests that it may have a higher specific surface area and more surface active sites.

[0056] Figure 3 The images show the UV-DRS diagrams of the catalysts prepared in Example 1 and Comparative Example 1 of this invention. It can be seen that pure CN has an absorption edge around 469 nm, indicating that CN has a relatively large band gap energy (2.64 eV). Furthermore, the maximum absorption wavelength of W-CN is approximately 514 nm, corresponding to a band gap energy of approximately 2.41 eV. Therefore, the introduction of a single W atom broadens the visible light absorption of pure CN, which means that sunlight can be utilized more effectively.

[0057] Figure 4 The PL plots are of the catalysts prepared in Example 1 and Comparative Example 1 of this invention. The PL intensity of W-C3N4 is significantly lower than that of pure C3N4, indicating that the doping of W may inhibit the recombination of photogenerated electron-hole pairs, thereby improving the separation efficiency of photogenerated carriers. The introduction of W provides a non-radiative recombination channel, which promotes the transfer of electrons from C3N4 to W species, thereby enhancing photocatalytic or photoelectric performance.

[0058] Example 1 Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min and use a white LED lamp to simulate sunlight to irradiate the light tube at an energy intensity of 10 W.

[0059] Weigh 15 mg of the CN catalyst prepared in Comparative Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min and use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0060] Every minute, 1 mL of ofloxacin aqueous solution from each of the two experimental groups was taken and filtered through a 0.45 μm filter membrane to obtain the filtrate. The ofloxacin concentration in the filtrate was then determined using high-performance liquid chromatography (HPLC). The results are as follows: Figure 5 As shown.

[0061] pass Figure 5 It can be seen that both CN and WCN-5 alone have a certain degradation effect on ofloxacin in water. However, the degradation effect of CN is very limited, reducing ofloxacin in water to only about 70%, while WCN-5 can reduce ofloxacin in water to about 38%. This confirms that the introduction of tungsten inhibits the recombination of photogenerated electron-hole pairs, thereby improving the separation efficiency of photogenerated carriers. It also promotes the transfer of electrons from C3N4 to W species, thus enhancing photocatalytic or photoelectric performance.

[0062] Example 2 Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0063] Weigh 15 mg of the CN catalyst prepared in Comparative Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0064] Add 15 mg of potassium persulfate to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L), stir for 30 min, and irradiate the light tube with a white LED lamp to simulate sunlight at an energy intensity of 10 W.

[0065] Weigh 15 mg of the WCN-3 catalyst prepared in Example 2 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0066] Weigh 15 mg of the WCN-7 catalyst prepared in Example 3 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0067] Weigh 15 mg of the WCN-9 catalyst prepared in Example 4 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0068] Every minute, 1 mL of ofloxacin aqueous solution from each of the six experimental groups was taken and filtered through a 0.45 μm filter membrane to obtain the filtrate. The ofloxacin concentration in the filtrate was then determined using high-performance liquid chromatography (HPLC). The results are as follows: Figure 6 As shown.

[0069] pass Figure 5 and Figure 6 The comparison shows that using WCN-5 to catalyze the activation of persulfate to degrade ofloxacin in water can almost completely degrade a certain concentration of ofloxacin within 10 minutes. Both the degradation rate and degradation efficiency are significantly improved, indicating that the catalyst of this invention has excellent catalytic activation performance for persulfate, thus effectively catalyzing and activating persulfate and significantly enhancing the degradation effect of persulfate on ofloxacin.

[0070] pass Figure 6 It can be seen that CN removed only 39.6% of OFL within 10 minutes of light irradiation, while potassium persulfate removed only 23.8% of OFL. However, the addition of NaOH to treat g-C3N4 with alkali and the introduction of WCl6 can significantly improve the activation of persulfate by g-C3N4. However, the amount of WCl6 introduced will affect the activation effect of the catalyst on persulfate, thus affecting the degradation effect on OFL. Among them, the WCN-5 sample had the best degradation effect, reaching 98.7%.

[0071] Example 3 Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin solution prepared with actual tap water, ofloxacin concentration in solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0072] Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin solution prepared with actual wastewater treatment plant effluent, ofloxacin concentration in solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0073] Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin solution prepared with artificial lake water in actual water body, ofloxacin concentration in solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0074] Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin solution was prepared using water from the actual Laoyu River, with an ofloxacin concentration of 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0075] Every minute, 1 mL of ofloxacin aqueous solution from each of the four experimental groups was taken and filtered through a 0.45 μm filter membrane to obtain the filtrate. The ofloxacin concentration in the filtrate was then determined using high-performance liquid chromatography (HPLC). The results are as follows: Figure 5 As shown.

[0076] pass Figure 7 It can be seen that the WCN-5 catalyst prepared in Example 1 has a degradation effect on ofloxacin in different actual water bodies. It can be basically completely degraded within 10 minutes, and has a higher degradation efficiency for sewage treatment plant effluent, fish-catching river water and artificial lake water, which proves the technical feasibility and high efficiency of the present invention and can be adapted to different water qualities.

[0077] Example of effect 4 Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0078] Weigh 15 mg of the WOCN catalyst prepared in Comparative Example 2 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0079] Every minute, 1 mL of ofloxacin aqueous solution from each of the two experimental groups was taken and filtered through a 0.45 μm filter membrane to obtain the filtrate. The ofloxacin concentration in the filtrate was then determined using high-performance liquid chromatography (HPLC). The results are as follows: Figure 7 As shown.

[0080] pass Figure 8 It can be seen that different tungsten sources in the catalyst affect the degradation of ofloxacin in water. The degradation rate of WO3 as the tungsten source can only reach 78%, while WCN-5 can degrade ofloxacin in water to about 98.7%. The catalyst prepared by WCl6 is even more effective because the tungsten in WCl6 exists in the form of a six-coordinate chloride. The chloride ligand makes the electron cloud of tungsten more easily polarized, enhancing its interaction with g-C3N4, thus making it easier to form active sites during the preparation process and improving the catalyst performance.

[0081] Example 5 Weigh 15 mg of the WCN-5 catalyst prepared in Example 1 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0082] Weigh 15 mg of the MWCN-0 catalyst prepared in Comparative Example 3 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0083] Weigh 15 mg of the MWCN-5 catalyst prepared in Example 5 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0084] Weigh 15 mg of the WCN-15 catalyst prepared in Example 6 and add it to a light tube containing 50 mL of ofloxacin aqueous solution (ofloxacin concentration in the solution is 10 mg / L). Stir for 30 min, then add 15 mg of potassium persulfate. Use a white LED lamp to simulate sunlight and irradiate the light tube at an energy intensity of 10 W.

[0085] Every minute, 1 mL of ofloxacin aqueous solution from each of the four experimental groups was taken and filtered through a 0.45 μm filter membrane to obtain the filtrate. The ofloxacin concentration in the filtrate was then determined using high-performance liquid chromatography (HPLC). The results are as follows: Figure 8 As shown.

[0086] pass Figure 9 It can be seen that different proportions of NaOH added as catalyst affect the degradation of ofloxacin in water. The best degradation effect was observed with 10 mg of NaOH added (WCN-5). This also confirms that alkaline treatment with sodium hydroxide optimizes the catalyst's electronic structure, improves the separation efficiency of photogenerated carriers, and enhances the dispersion and binding of tungsten, thereby improving catalyst performance and significantly increasing the degradation efficiency of ofloxacin.

[0087] Figure 10 The WCN-5 catalyst was subjected to multiple cycles of experiments under the same conditions. It can be seen that the WCN-5 catalyst has good stability. After five cycles of photocatalytic degradation of OFL, the WCN-5 catalyst still maintained considerable performance. Its good stability makes it have certain potential for large-scale application.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a tungsten-anchored g-C3N4 photocatalyst, characterized in that: Includes the following steps: (1) Melamine was calcined to obtain yellow g-C3N4 blocks; (2) Yellow g-C3N4 block, NaOH and WCl6 are mixed and ground under infrared lamp, then water is added and ultrasonic is performed. After ultrasonication, the powder is dried, and the powder obtained by drying is calcined. The calcined product is washed and dried to obtain tungsten-anchored g-C3N4 photocatalyst.

2. The preparation method of a tungsten-anchored g-C3N4 photocatalyst according to claim 1, characterized in that: In step (1), the calcination conditions are to heat to 500-550°C at a heating rate of 5-10°C / min in an air atmosphere and calcine for 1.5-3 hours.

3. The method for preparing a tungsten-anchored g-C3N4 photocatalyst according to claim 1, characterized in that: In step (2), the mass ratio of yellow g-C3N4 block, NaOH and WCl6 is yellow g-C3N4 block:NaOH:WCl6=1:(0.05~0.1):(0.03~0.09).

4. The method for preparing a tungsten-anchored g-C3N4 photocatalyst according to claim 1, characterized in that: In step (2), the calcination conditions are to heat to 500-550℃ at a heating rate of 5-10℃ / min under a nitrogen atmosphere and calcine for 3-4 hours.

5. The application of the tungsten-anchored g-C3N4 photocatalyst prepared by the method according to any one of claims 1 to 4 in the degradation of ofloxacin by activating persulfate.

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