A method of photocatalytic enhanced aging of microplastics by peroxy monosulfate

Abstract

This invention belongs to the field of environmental pollution control technology, specifically relating to a method for photocatalytically enhanced peroxymonosulfate (PMS) aging of microplastics. The invention involves adding peroxymonosulfate and a photocatalytic enhancement catalyst to water containing microplastics, thereby conducting a photocatalytically enhanced degradation reaction to obtain aged microplastics. The photocatalytic enhancement catalyst comprises graphitic carbon nitride and silicon carbide supported on the surface of the graphitic carbon nitride. This invention achieves efficient aging of various microplastics under mild conditions through the synergistic effect of photocatalysis and PMS oxidation via the photocatalytic enhancement catalyst, while ensuring the cyclic stability and easy recyclability of the catalyst, providing a practical and feasible technical solution for the treatment of microplastic pollution in water bodies.

Description

Technical Field

[0001] This invention belongs to the field of environmental pollution control technology, specifically relating to a method for photocatalytically enhanced peroxymonosulfate aging of microplastics. Background Technology

[0002] Microplastics, as a new type of pollutant widely present in the environment, have been detected in various environmental media such as water, soil, and atmosphere due to their small particle size, recalcitrant nature, and high mobility, posing a potential threat to ecosystems and human health. Existing microplastic remediation technologies mainly include physical removal, biodegradation, and advanced oxidation, but all have significant limitations: physical removal can only achieve the transfer of microplastics and cannot fundamentally degrade them; biodegradation rates are slow and have limited effectiveness on recalcitrant microplastics (such as PE and PVC); traditional advanced oxidation technologies (such as photocatalysis alone and peroxide oxidation) suffer from low reaction efficiency, insufficient free radical utilization, and the need for stringent reaction conditions, making it difficult to meet the practical needs of microplastic pollution remediation in water bodies.

[0003] An advanced oxidation process combining photocatalysis with peroxymonosulfate (PMS) generates sulfate radicals (·SO4) through the catalysis of PMS. - Strong oxidizing free radicals such as hydroxyl radicals (·OH) can damage the surface structure of microplastics, achieving their aging and degradation, and represent a highly promising direction for microplastic remediation. However, in existing combined systems, catalysts often suffer from defects such as poor thermal conductivity, high photogenerated carrier recombination rate, and insufficient cycle stability, resulting in low free radical generation efficiency and poor microplastic aging effects. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method for photocatalytically enhanced peroxymonosulfate aging of microplastics. This invention enhances the synergistic effect of photocatalysis and PMS oxidation by enhancing the catalyst, thereby achieving efficient aging of various microplastics under mild conditions, while ensuring the cyclic stability and easy recyclability of the catalyst, thus providing a practical and feasible technical solution for the treatment of microplastic pollution in water bodies.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for photocatalytically enhancing peroxymonosulfate-aged microplastics, comprising the following steps: Peroxymonosulfate and a photocatalytic enhancement catalyst were added to the water containing microplastics to carry out a photocatalytic enhanced degradation reaction to obtain aged microplastics. The photocatalytic enhancement catalyst comprises graphitic carbon nitride and silicon carbide supported on the surface of the graphitic carbon nitride.

[0006] Preferably, the microplastics include one or more of polyethylene terephthalate, polylactic acid, polybutylene succinate, polyethylene, polyvinyl chloride, and polystyrene.

[0007] Preferably, the dosage of the photocatalytic enhancement catalyst in the microplastic-containing water body to be treated is 0.3~1.2 g / L.

[0008] Preferably, the dosage of peroxymonosulfate in the microplastic-containing water body to be treated is 0.5~2.0 mmol / L.

[0009] Preferably, the photocatalytic enhanced degradation reaction is carried out under xenon lamp irradiation; the power of the xenon lamp is 150~300W and the wavelength λ≥420nm.

[0010] Preferably, the temperature of the photocatalytic enhanced degradation reaction is 35~55℃, and the reaction time is 3~8h.

[0011] Preferably, the preparation method of the photocatalytic enhancement catalyst includes the following steps: Graphitic carbon nitride, silicon carbide and water are mixed and subjected to a hydrothermal reaction. The resulting hydrothermal reaction product is then calcined to obtain a photocatalytic enhancement catalyst.

[0012] Preferably, the mass ratio of silicon carbide to graphitic carbon nitride is 0.5~4:1~8.

[0013] Preferably, the calcination temperature is 450~550℃, and the holding time is 2~4h.

[0014] Preferably, the hydrothermal reaction temperature is 50~60℃, and the holding time is 6~12h.

[0015] This invention provides a method for photocatalytically enhancing peroxymonosulfate-aged microplastics, comprising the following steps: Peroxymonosulfate and a photocatalytic enhancement catalyst were added to the water containing microplastics to carry out a photocatalytic enhanced degradation reaction to obtain aged microplastics. The photocatalytic enhancement catalyst comprises graphitic carbon nitride and silicon carbide supported on the surface of the graphitic carbon nitride.

[0016] The beneficial effects of this invention are as follows: 1. Catalyst structure innovation: SiC-modified g-C3N4 is used to construct a composite catalyst. The high thermal conductivity of SiC can effectively promote heat transfer in the reaction system, reduce the recombination rate of photogenerated carriers, and improve the structural stability of the catalyst, thus solving the problem of insufficient performance of traditional g-C3N4 catalysts.

[0017] 2. Innovative Synergistic Mechanism: Integrating photocatalysis, peroxymonosulfate (PMS) oxidation, and thermal conduction enhancement technologies, the three work together to generate a large number of highly oxidizing free radicals, which rapidly break the chemical bonds on the surface of microplastics and significantly improve aging efficiency. Compared with single oxidation or photocatalysis technologies, the aging effect is improved by more than 1 times.

[0018] 3. Mild and controllable reaction conditions: The reaction pH value can be adapted to a wide range (5.5~8.5), the temperature can be controlled at 35~55℃, no extreme reaction conditions are required, energy consumption is low, and it is suitable for the treatment of microplastics in different water quality environments.

[0019] 4. Highly practical and environmentally friendly: The catalyst can be quickly recovered through centrifugation and reused more than 10 times, reducing processing costs; it is suitable for various microplastics such as PET, PLA, PE, and PVC. After aging, the specific surface area of ​​microplastics is significantly increased, laying the foundation for subsequent deep degradation or removal, without the risk of secondary pollution. Detailed Implementation

[0020] This invention provides a method for photocatalytically enhancing peroxymonosulfate-aged microplastics, comprising the following steps: Peroxymonosulfate and a photocatalytic enhancement catalyst were added to the water containing microplastics to carry out a photocatalytic enhanced degradation reaction to obtain aged microplastics. The photocatalytic enhancement catalyst comprises graphitic carbon nitride (g-C3N4) and silicon carbide (SiC) supported on the surface of the graphitic carbon nitride.

[0021] Unless otherwise specified, the present invention does not have special requirements on the source of raw materials used, and commercially available products well known to those skilled in the art can be used.

[0022] In one embodiment, the mass percentage of graphitic carbon nitride (g-C3N4) in the photocatalytic enhancement catalyst is 60-94.12%, specifically 60%, 80% or 94.12% in the embodiment, and the mass percentage of silicon carbide (SiC) is 5.88-40%, specifically 5.88%, 20% or 40% in the embodiment.

[0023] As one embodiment, the preparation method of the photocatalytic enhancement catalyst includes the following steps: Graphitic carbon nitride, silicon carbide and water are mixed and subjected to a hydrothermal reaction. The resulting hydrothermal reaction product is then calcined to obtain a photocatalytic enhancement catalyst.

[0024] In one embodiment, the silicon carbide is pretreated silicon carbide; the pretreatment involves sequentially calcining, cooling to room temperature, and acid leaching the silicon carbide, followed by solid-liquid separation, and the resulting solid is sequentially washed and dried; the calcination temperature is ≥700℃, specifically 700℃ in this embodiment, and the holding time is ≥0.5h, specifically 0.5h in this embodiment; the reagent used for acid leaching is HF solution; the mass concentration of the HF solution is ≥40wt%, specifically 40% in this embodiment; the acid leaching time is ≥12h, specifically 12h in this embodiment; the solid-liquid separation is centrifugal separation; the reagent used for washing is ultrapure water; the washing is performed until the pH value is 6.8~7.2, specifically 7.0 in this embodiment; the drying equipment used is a vacuum drying oven; the drying temperature is ≥60℃, specifically 60℃ in this embodiment, and the drying time is ≥10h, specifically 10h in this embodiment.

[0025] In one embodiment, the mass ratio of silicon carbide (SiC) to graphitic carbon nitride (g-C3N4) is 0.5~4:1~8, and in specific embodiments it is 0.5:8, 3:2 or 4:1; the water is deionized water; the mass ratio of graphitic carbon nitride to water volume is (3~8)g:50mL, and in specific embodiments it is 8g:50mL or 3g:50mL or 6g:50mL.

[0026] In one embodiment, the mixing of graphitic carbon nitride, silicon carbide, and water involves placing graphitic carbon nitride in water, ultrasonically dispersing it, adding silicon carbide, stirring, and adjusting the pH to 6.8-7.2. The ultrasonic dispersion power is 150-200W, specifically 150W in this embodiment, the frequency is 40-50kHz, specifically 40kHz in this embodiment, and the time is 30-60min, specifically 30min in this embodiment. The pH is then adjusted to 7.

[0027] In one embodiment, the temperature of the hydrothermal reaction is 50~60℃, specifically 60℃ in this embodiment, and the holding time is 6~12h, specifically 6h in this embodiment. After the hydrothermal reaction, the process further includes: sequentially performing solid-liquid separation and washing on the products of the hydrothermal reaction; the solid-liquid separation is filtration; the reagent used for washing is deionized water, and the washing is performed 3~5 times, specifically 3 times in this embodiment.

[0028] In one embodiment, the calcination is carried out in a protective gas; the protective gas is nitrogen; the heating rate from room temperature to the calcination temperature is 5~10℃ / min, specifically 5℃ / min or 10℃ / min in this embodiment; the calcination temperature is 450~550℃, specifically 450℃, 500℃ or 550℃ in this embodiment, and the holding time is 2~4h, specifically 2h, 3h or 4h in this embodiment; after calcination, the process further includes: cooling the calcined product and then grinding it.

[0029] In one embodiment, peroxymonosulfate and a photocatalytic enhancement catalyst are added to the water containing microplastics.

[0030] In one embodiment, the microplastics include one or more of polyethylene terephthalate (PET), polylactic acid (PLA), polybutylene succinate (PBS), polyethylene (PE), polyvinyl chloride (PVC), and polystyrene (PS), with a specific embodiment being polyethylene terephthalate (PET), polylactic acid (PLA), polybutylene succinate (PBS), polyethylene (PE), polyvinyl chloride (PVC), or polystyrene (PS); the mass content of microplastics in the water to be treated is 50~200 mg / L, with a specific embodiment being 50 mg / L; the peroxymonosulfate (PMS) includes one or more of sodium peroxymonosulfate, potassium peroxymonosulfate, ammonium peroxymonosulfate, calcium peroxymonosulfate, and magnesium peroxymonosulfate, with a specific embodiment being potassium peroxymonosulfate.

[0031] In one implementation method, the dosage of the photocatalytic enhancement catalyst in the microplastic-containing water body to be treated is 0.3~1.2 g / L, specifically 0.3 g / L or 1.2 g / L in this embodiment, and the dosage of peroxymonosulfate (PMS) is 0.5~2.0 mmol / L, specifically 0.5 mmol / L or 2.0 mmol / L in this embodiment. After adding peroxymonosulfate and the photocatalytic enhancement catalyst to the microplastic-containing water body to be treated, the process further includes: stirring until homogeneous; the stirring rate is 150~300 rpm, specifically 150 rpm or 300 rpm in this embodiment; the photocatalytic enhancement degradation reaction is carried out under xenon lamp irradiation; the power of the xenon lamp is 150~300 W, specifically 300 W in this embodiment, and the wavelength λ≥420 nm; the temperature of the photocatalytic enhancement degradation reaction is 35~55℃, specifically 35℃, 40℃ or 55℃ in this embodiment, and the reaction time is 3~8 h, specifically 3 h, 5 h or 8 h in this embodiment.

[0032] As one implementation method, after the photocatalytic enhanced degradation reaction is completed, the process further includes: solid-liquid separation, in which the obtained solid is sequentially washed, filtered and dried to obtain aged microplastics; the reagent used for washing is distilled water; the number of washing cycles is ≥3 times, specifically 3 times in this embodiment; the drying temperature is ≥60℃, specifically 60℃ in this embodiment, and the drying time is ≥10h, specifically 10h in this embodiment.

[0033] As one implementation method, after the photocatalytic enhanced degradation reaction, the process further includes: centrifugation to recover the photocatalytic enhanced catalyst for reuse; the number of times the catalyst is reused is ≥10 times, specifically 10 times in this embodiment; the recovered photocatalytic enhanced catalyst is reused more than 10 times to maintain stable aging performance.

[0034] This invention provides a method for photocatalytically enhanced peroxymonosulfate (PMS) aging of microplastics. By preparing a SiC / g-C3N4 thermally conductive catalyst and combining it with a PMS photocatalytic system, efficient aging of microplastics is achieved under mild conditions. The catalyst of this invention exhibits excellent thermal conductivity, is reusable, and can synergistically generate strong oxidizing free radicals with PMS, rapidly disrupting the surface structure of microplastics, increasing their specific surface area and surface negative charge density, and accelerating subsequent degradation or removal of microplastics. This method is simple to operate, operates under mild reaction conditions, and has a wide range of applications, effectively treating various types of microplastic pollution and showing promising practical application prospects.

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, but they should not be construed as limiting the scope of protection of the present invention.

[0036] Preparation of microplastic solution: Accurately weigh appropriate amounts of one or more of the following microplastics: polyethylene terephthalate (PET), polylactic acid (PLA), polybutylene succinate (PBS), polyethylene (PE), polyvinyl chloride (PVC), and polystyrene (PS), and prepare a microplastic solution with a concentration of 50 mg / L. Adjust the pH to 7.0 and set aside for later use.

[0037] Example 1 SiC powder was calcined in a muffle furnace at 700℃ for 0.5h, cooled to room temperature, immersed in 40wt% HF solution for 12h, centrifuged, washed with ultrapure water until pH=7.0, dried in a vacuum drying oven at 60℃ for 10h, and then dried for later use. 8 g of g-C3N4 was weighed and placed in 50 mL of deionized water, and ultrasonically dispersed at 150 W power and 40 kHz frequency for 30 min. 0.5 g of pretreated SiC powder was added, and the mixture was stirred at 200 rpm until homogeneous. The pH was adjusted to 7.0, and the reaction was carried out at 60 °C for 6 h. The reaction product was filtered, and the resulting solid was washed three times with deionized water. The solid was placed in a nitrogen atmosphere furnace and calcined at 450 °C at a heating rate of 5 °C / min for 2 h. After cooling, the solid was ground to obtain the SiC / g-C3N4-1 catalyst, in which the SiC content was 5.88%. Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus. Potassium persulfate was added to a concentration of 0.5 mmol / L, followed by SiC / g-C3N4-1 catalyst to a concentration of 0.3 g / L. The mixture was stirred at 200 rpm until homogeneous, and then irradiated with a xenon lamp (300 W, λ ≥ 420 nm). The reaction temperature was controlled at 35 °C, and the reaction time was 8 h. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, and dried at 60 °C for 10 h after vacuum filtration to obtain aged microplastics, which were named APET-1, APLA-1, APBS-1, APE-1, APVC-1, and APS-1, respectively.

[0038] Example 2 SiC powder was calcined in a muffle furnace at 700℃ for 0.5h, cooled to room temperature, immersed in 40wt% HF solution for 12h, centrifuged, washed with ultrapure water until pH=7.0, dried in a vacuum drying oven at 60℃ for 10h, and then dried for later use. Weigh 3g of g-C3N4 and place it in 50mL of deionized water. Disperse the mixture ultrasonically at 150W power and 40kHz frequency for 30min. Add 2g of pretreated SiC powder, stir at 200rpm until homogeneous, adjust the pH to 7.0, and react at 60℃ for 6h. Filter the reaction product, wash the resulting solid three times with deionized water, place it in a nitrogen atmosphere furnace, raise the temperature to 550℃ at a rate of 10℃ / min, calcine for 4h, cool, and grind to obtain SiC / g-C3N4-2 catalyst, wherein the SiC content is 40%. Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus. Potassium persulfate was added to a concentration of 2 mmol / L, followed by SiC / g-C3N4-2 catalyst to a concentration of 1.2 g / L. The mixture was stirred at 200 rpm until homogeneous, and then irradiated with a xenon lamp (300 W, λ ≥ 420 nm). The reaction temperature was controlled at 55 °C for 3 h. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, and dried at 60 °C for 10 h after vacuum filtration to obtain aged microplastics, which were named APET-2, APLA-2, APBS-2, APE-2, APVC-2, and APS-2, respectively.

[0039] Example 3 SiC powder was calcined in a muffle furnace at 700℃ for 0.5h, cooled to room temperature, immersed in 40wt% HF solution for 12h, centrifuged, washed with ultrapure water until pH=7.0, dried in a vacuum drying oven at 60℃ for 10h, and then dried for later use. 6 g of g-C3N4 was weighed and placed in 50 mL of deionized water, and ultrasonically dispersed at 150 W power and 40 kHz frequency for 30 min. 1.5 g of pretreated SiC powder was added, and the mixture was stirred at 200 rpm until homogeneous. The pH was adjusted to 7.0, and the reaction was carried out at 60 °C for 6 h. The reaction product was filtered, and the resulting solid was washed three times with deionized water. The solid was placed in a nitrogen atmosphere furnace and heated to 500 °C at a heating rate of 10 °C / min. The solid was calcined for 3 h, cooled, and then ground to obtain the SiC / g-C3N4-3 catalyst, in which the SiC content was 20%. Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus. Potassium persulfate was added to a concentration of 2 mmol / L, followed by SiC / g-C3N4-3 catalyst to a concentration of 0.8 g / L. The mixture was stirred at 200 rpm until homogeneous, and then irradiated with a xenon lamp (300 W, λ ≥ 420 nm). The reaction temperature was controlled at 40 °C, and the reaction time was 5 h. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, filtered, and dried at 60 °C for 10 h to obtain aged microplastics, which were named APET-3, APLA-3, APBS-3, APE-3, APVC-3, and APS-3, respectively.

[0040] Comparative Example 1 Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus, and potassium persulfate was added to a concentration of 0.5 mmol / L. The mixture was stirred at 200 rpm until homogeneous, and then irradiated with a xenon lamp (300 W, λ ≥ 420 nm). The reaction temperature was controlled at 35 °C, and the reaction time was 8 h. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, filtered, and dried at 60 °C for 10 h to obtain aged microplastics, which were named APET-1-1, APLA-1-1, APBS-1-1, APE-1-1, APVC-1-1, and APS-1-1, respectively.

[0041] Comparative Example 2 Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus, and potassium persulfate was added to a concentration of 2 mmol / L. The mixture was stirred at 200 rpm until homogeneous, and then irradiated with a xenon lamp (300 W, λ ≥ 420 nm). The reaction temperature was controlled at 55 °C, and the reaction time was 3 h. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, filtered, and dried at 60 °C for 10 h to obtain aged microplastics, which were named APET-2-1, APLA-2-1, APBS-2-1, APE-2-1, APVC-2-1, and APS-2-1, respectively.

[0042] Comparative Example 3 Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus, and potassium persulfate was added to a concentration of 2 mmol / L. The mixture was stirred at 200 rpm until homogeneous, and then irradiated with a xenon lamp (300 W, λ ≥ 420 nm). The reaction temperature was controlled at 40 °C, and the reaction time was 5 h. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, filtered, and dried at 60 °C for 10 h to obtain aged microplastics, which were named APET-3-1, APLA-3-1, APBS-3-1, APE-3-1, APVC-3-1, and APS-3-1, respectively.

[0043] Comparative Example 4 Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus and stirred at 200 rpm until homogeneous. Xenon lamp irradiation (300 W, λ ≥ 420 nm) was applied, and the reaction temperature was controlled at 35°C for 8 hours. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, and dried at 60°C for 10 hours after vacuum filtration to obtain aged microplastics, which were named APET-1-2, APLA-1-2, APBS-1-2, APE-1-2, APVC-1-2, and APS-1-2, respectively.

[0044] Comparative Example 5 Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus and stirred at 200 rpm until homogeneous. Xenon lamp irradiation (300 W, λ ≥ 420 nm) was applied, and the reaction temperature was controlled at 55°C for 3 hours. After the reaction, the microplastics were separated by filtration, washed three times with distilled water, and dried at 60°C for 10 hours after filtration to obtain aged microplastics, which were named APET-2-2, APLA-2-2, APBS-2-2, APE-2-2, APVC-2-2, and APS-2-2, respectively.

[0045] Comparative Example 6 Each microplastic solution containing a single type of microplastic was placed in a constant-temperature reaction apparatus and stirred at 200 rpm until homogeneous. Xenon lamp irradiation (300W power, λ≥420nm) was applied, and the reaction temperature was controlled at 40℃ for 5 hours. After the reaction, the microplastics were separated by filtration, washed three times repeatedly with distilled water, filtered, and dried at 60℃ for 10 hours to obtain aged microplastics, which were named APET-3-2, APLA-3-2, APBS-3-2, APE-3-2, APVC-3-2, and APS-3-2, respectively.

[0046] Performance testing Microplastic aging effect test: The specific surface area of ​​microplastics before and after aging was detected by a specific surface area analyzer, and the isoelectric point (pH value when the surface charge is zero) was measured by a Zeta potentiometer. The results are shown in Table 1.

[0047] Table 1. Aging effect of microplastics

[0048] As shown in Table 1, after aging using the method of this invention, the specific surface area of ​​all microplastics increased significantly, while the isoelectric point decreased, indicating that the surface structure of the microplastics was destroyed, the negative charge increased, and the aging effect was significant. Among them, the specific surface area of ​​PLA microplastics changed most significantly, indicating that they are more susceptible to aging by free radicals.

[0049] Catalyst lifetime test: The aging reaction in Example 1 was repeated 10 times. After each reaction, the SiC / g-C3N4-1 catalyst was recovered by centrifugation, washed, dried, and reused. The results showed that after 10 cycles, the increase in specific surface area and the decrease in isoelectric point of the microplastics were not significantly reduced compared with the first use, indicating that the catalyst has excellent stability and reusability.

[0050] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method of photocatalytically reinforced aging of microplastics with peroxy monosulfate characterized in that, Includes the following steps: Peroxymonosulfate and a photocatalytic enhancement catalyst were added to the water containing microplastics to carry out a photocatalytic enhanced degradation reaction to obtain aged microplastics. The photocatalytic enhancement catalyst comprises graphitic carbon nitride and silicon carbide supported on the surface of the graphitic carbon nitride.

2. The method of claim 1, wherein, The microplastics include one or more of polyethylene terephthalate, polylactic acid, polybutylene succinate, polyethylene, polyvinyl chloride, and polystyrene.

3. The method of claim 1, wherein, The dosage of the photocatalytic enhancement catalyst in the microplastic-containing water body to be treated is 0.3~1.2 g / L.

4. The method of claim 1, wherein, The dosage of peroxymonosulfate in the water containing microplastics is 0.5~2.0 mmol / L.

5. The method according to claim 1, characterized in that, The photocatalytic enhanced degradation reaction is carried out under xenon lamp irradiation; the power of the xenon lamp is 150~300W and the wavelength λ≥420nm.

6. The method according to claim 1, characterized in that, The photocatalytic enhanced degradation reaction is carried out at a temperature of 35-55℃ for 3-8 hours.

7. The method according to claim 1, characterized in that, The preparation method of the photocatalytic enhancement catalyst includes the following steps: Graphitic carbon nitride, silicon carbide and water are mixed and subjected to a hydrothermal reaction. The resulting hydrothermal reaction product is then calcined to obtain a photocatalytic enhancement catalyst.

8. The method according to claim 7, characterized in that, The mass ratio of silicon carbide to graphitic carbon nitride is 0.5~4:1~8.

9. The method according to claim 7, characterized in that, The calcination temperature is 450~550℃, and the holding time is 2~4h.

10. The method according to claim 7, characterized in that, The hydrothermal reaction is carried out at a temperature of 50-60℃ for 6-12 hours.

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