A method for mineralizing organic pollutants in surface water

Abstract

This invention discloses a method for mineralizing organic pollutants in surface water. The method involves mixing a photocatalyst, a heterogeneous Fenton catalyst, and organic pollutants, followed by illumination to achieve mineralization. The chemical structure of the photocatalyst is shown in Formula I, where n ≥ 1. This invention combines a photocatalyst with a heterogeneous Fenton catalyst to form a photocatalytic self-Fenton catalytic system. Selective degradation of pollutants and generation of hydrogen peroxide are achieved through oxygen-centered organic free radicals (OCORs) fixed on the surface of the photocatalyst. Under the action of the heterogeneous Fenton catalyst, hydrogen peroxide is activated in situ into highly oxidizing hydroxyl radicals, thereby enabling interaction between different active species and effectively improving the mineralization rate of organic pollutants.

Description

Technical Field

[0001] This invention relates to the field of catalyst technology containing organic compounds, and more specifically, to a method for mineralizing organic pollutants in surface water. Background Technology

[0002] Rapid global population growth and industrialization have exacerbated water pollution problems, posing a significant threat to social sustainability and human health worldwide. Currently, most methods employ advanced oxidation processes to mineralize and degrade organic pollutants by generating highly reactive oxidants within the reaction system. For example, the Fenton reaction utilizes ferric ions to catalyze the generation of reactive species such as hydroxyl groups from hydrogen peroxide to degrade organic pollutants. However, this method suffers from drawbacks such as a narrow effective pH range (2–4), low hydrogen peroxide utilization, and the potential for secondary pollution due to ferric ion precipitation.

[0003] Unlike Fenton oxidation, photocatalysis is a promising and sustainable water treatment method. Especially in heterogeneous Fenton systems, photocatalysts are increasingly used to promote Fenton oxidation, leveraging the combined effect of light and oxidants to generate a strong oxidizing effect and enhance the degradation of organic pollutants. For example, existing technologies disclose a visible light-assisted Fenton catalyst and its preparation method. This involves synthesizing macroporous structures using a dual-template method with three-dimensionally ordered colloidal particles as hard templates, long-chain surfactants as mesoporous pore-forming agents, and then combining this with calcination treatment of interconnected macroporous-mesoporous materials. This catalyst can be used in photo-Fenton systems, but it often requires excitation light exceeding the intensity of natural light to achieve a high mineralization rate. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings and deficiencies of existing photocatalytic Fenton catalysts in achieving low mineralization rates of organic pollutants under low-intensity light conditions, and to provide a method for mineralizing organic pollutants in surface water.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution:

[0006] This invention relates to a method for protecting organic pollutants in mineralized surface water, comprising the following steps:

[0007] The organic pollutants are mineralized by mixing a photocatalyst, a heterogeneous Fenton catalyst, and an organic pollutant and then irradiating them with light. The chemical structure of the photocatalyst is shown in Formula I, where n ≥ 1.

[0008]

[0009] This invention combines a photocatalyst with a heterogeneous Fenton catalyst to form a photocatalytic self-Fenton catalytic system. Through the oxygen-centered organic free radicals (OCORs) fixed on the surface of the photocatalyst, the selective degradation of pollutants and the generation of hydrogen peroxide are achieved. Under the action of the heterogeneous Fenton catalyst, hydrogen peroxide is activated in situ into a highly oxidizing hydroxyl radical, thereby enabling different active species to interact and effectively improve the mineralization rate of organic pollutants.

[0010] Moreover, unlike the existing photocatalytic hydrogen peroxide generation pathway (where photogenerated electrons directly react with oxygen to generate superoxide radical intermediates, and then the superoxide radicals gain another electron to generate hydrogen peroxide), the photocatalyst with the above-mentioned special structure can not only avoid the attack of free radicals on the catalyst itself during the photocatalytic process, thus avoiding its instability, but also has high photon utilization, and can effectively mineralize pollutants even under low light intensity.

[0011] Optionally, the mass ratio of the photocatalyst to the heterogeneous Fenton catalyst is 1:(0.5-1.5). The amount of heterogeneous Fenton catalyst is adapted to the amount of photocatalyst so that the H2O2 generated by the photocatalyst is completely consumed by the heterogeneous Fenton catalyst.

[0012] Specifically, the heterogeneous Fenton catalyst is K-FeOCl(K + The intercalated iron(II) oxychloride, FeOCl (ferric oxychloride), FeOOH (ferric hydroxide), Fhy (ferrous hydrate) or FeP (ferric phosphide) is at least one of these.

[0013] Optionally, the intensity of the light is ≤100mW / cm². 2 Preferably ≤10mW / cm 2 Moreover, photocatalysis does not require the introduction of additional oxygen or the addition of a sacrificial agent from the Fenton catalytic system.

[0014] Optionally, the concentration of the photocatalyst is 0.05–0.2 g / L, specifically 0.05 g / L, 0.1 g / L, 0.15 g / L, or 0.2 g / L; the concentration of the heterogeneous Fenton catalyst is 0.05–0.3 g / L, specifically 0.05 g / L, 0.1 g / L, 0.15 g / L, 0.2 g / L, 0.25 g / L, or 0.3 g / L.

[0015] Optionally, the organic pollutant has a pH of 3 to 9 and may also include Cl. - SO4 2- NO3 - The presence of multiple anions fully demonstrates that the method for mineralizing organic pollutants in surface water according to this invention can be applied to various complex environments and can still efficiently degrade organic pollutants under conditions of pH=3 to 9 and the presence of multiple anions.

[0016] Optionally, the photocatalyst is prepared by the following method: in an inert atmosphere, using 3,3',6,6'-tetrabromo-9,9'-biscarbazole and 2,6-diethynylanthraquinone as polymerization monomers, a photocatalyst is obtained by a photocatalyst coupling reaction in an organic solvent; wherein the photocatalyst coupling reaction is carried out at a temperature of 80-90°C for a time of 36-48 h.

[0017] Specifically, the preparation method of the above-mentioned photocatalyst includes the following steps:

[0018] S1. Preparation of anthraquinone precursor: Under an inert atmosphere, 2,6-dibromoanthraquinone, trimethylsilylacetylene and catalyst were added to a mixed solvent of tetrahydrofuran and diisopropylamine, heated to a certain temperature and held for a certain time to generate anthraquinone precursor through a stalk coupling reaction;

[0019] Preparation of S2,2,6-diethynylanthraquinone: The anthraquinone precursor in S1 was reacted with tetrabutylammonium fluoride in chloroform solvent to remove the silicon protecting group. The 2,6-diethynylanthraquinone was obtained by extraction and drying.

[0020] S3. Under an inert atmosphere, 3,3',6,6'-tetrabromo-9,9'-biscarbazole, 2,6-diethynylanthraquinone from S2, and an organic solvent are mixed to carry out a stalk coupling reaction to obtain a photocatalyst; wherein the temperature of the stalk coupling reaction is 80-90℃ and the time is 36-48h.

[0021] More specifically, in step S1, the molar ratio of 2,6-dibromoanthraquinone to trimethylsilylacetylene is 1:4; the catalyst is bis(triphenylphosphine)palladium chloride and cuprous iodide in a molar ratio of 1:1; the volume ratio of tetrahydrofuran to diisopropylamine is 1:1; and the heating temperature is 75°C for 24 hours.

[0022] Furthermore, the molar ratio of the anthraquinone precursor to tetrabutylammonium fluoride in step S2 is 1:4.

[0023] In step S3, the molar ratio of 3,3',6,6'-tetrabromo-9,9'-biscarbazole to 2,6-diethynylanthraquinone is 1:2; the catalyst is bis(triphenylphosphine)palladium chloride and cuprous iodide in a molar ratio of 1:1; and the solvent is triethylamine and N,N-dimethylformamide in a volume ratio of 1:1.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] This invention combines a photocatalyst with a heterogeneous Fenton catalyst to form a photocatalytic self-Fenton catalytic system, breaking the traditional degradation pathway of reactive oxygen species. By increasing the electron-donating ability of the electron-donating unit, the amount of OCORs generated in the system is increased, thereby improving the degradation efficiency. Combined with oxygen-centered organic radicals (OCORs) fixed on the surface of the photocatalyst, selective degradation of pollutants and generation of hydrogen peroxide are achieved. Under the action of the heterogeneous Fenton catalyst, hydrogen peroxide is activated in situ into highly oxidizing hydroxyl radicals, thereby enabling different reactive species to interact and effectively improve the mineralization rate of organic pollutants.

[0026] During the degradation of organic pollutants, the photon utilization rate at 470 nm reached 32%, enabling the photocatalytic self-Fenton catalytic system to operate under low light intensity conditions (10 mW / cm²). 2 It can also effectively mineralize pollutants. Furthermore, even after 10 consecutive cycles of use, it maintains a high rate of mineralization of organic pollutants and exhibits excellent stability. Attached Figure Description

[0027] Figure 1 The XRD patterns are those of the photocatalyst BCz-AQ in Example 3 and the photocatalyst Cz-AQ in Comparative Example 1.

[0028] Figure 2 The infrared spectra are those of the photocatalyst BCz-AQ in Example 3 and the photocatalyst Cz-AQ in Comparative Example 1.

[0029] Figure 3 Solid-state carbon NMR spectra of photocatalyst BCz-AQ in Example 3 and photocatalyst Cz-AQ in Comparative Example 1.

[0030] Figure 4 Transmission electron microscopy (TEM) images of photocatalyst BCz-AQ in Example 3 and photocatalyst Cz-AQ in Comparative Example 1.

[0031] Figure 5 The UV diffuse reflectance spectra of photocatalyst BCz-AQ in Example 3 and photocatalyst Cz-AQ in Comparative Example 1 are shown.

[0032] Figure 6 This is a comparison chart of the catalytic performance of different catalysts.

[0033] Figure 7 This is a comparison diagram of the photocatalytic processes and the active species involved in the heterogeneous self-Fenton process of photocatalyst BCz-AQ in Example 3.

[0034] Figure 8 This is a comparison diagram of the in-situ EPR monitoring of OCOs intensity changes between the photocatalyst BCz-AQ in Example 3 and the photocatalyst Cz-AQ in Comparative Example 1.

[0035] Figure 9 This is a comparison of the degradation efficiency of the photocatalytic self-Fenton catalytic system composed of photocatalyst BCz-AQ and K-FeOCl in Example 3 under weak light and different pH and multiple anion conditions.

[0036] Figure 10 This is a comparison chart showing the degradation efficiency of the photocatalytic self-Fenton catalytic system composed of photocatalysts BCz-AQ and K-FeOCl in Example 3 under different actual environmental conditions. Detailed Implementation

[0037] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0038] Example 1

[0039] Anthraquinone precursors can be prepared by the following methods:

[0040] 1 g of 2,6-dibromoanthraquinone, 19.2 mg of bis(triphenylphosphine)palladium chloride and 5.2 mg of cuprous iodide were placed in a flask, 60 mL of tetrahydrofuran and 60 mL of diisopropylamine were added, and the mixture was stirred for 30 min under an argon atmosphere. Then 1.5 mL of trimethylsilylacetylene was added, and the mixture was heated to 75 °C and reacted for 24 h to obtain the anthraquinone precursor.

[0041] Example 2

[0042] 2,6-Diethynylanthraquinone can be prepared by the following method:

[0043] 500 mg of the anthraquinone precursor from Example 1 was reacted with 1.28 g of tetrabutylammonium fluoride in 40 mL of chloroform solvent to remove the silicon protecting group. The mixture was then extracted and dried to obtain 2,6-diethynylanthraquinone.

[0044] Example 3

[0045] A photocatalyst (BCz-AQ) can be prepared by the following method:

[0046] 100 mg of 3,3',6,6'-tetrabromo-9,9'-biscarbazole, 79 mg of 2,6-diethynylanthraquinone from Example 2, 10.8 mg of bis(triphenylphosphine)palladium chloride, and 2.9 mg of cuprous iodide were placed in a flask, and 14 mL of N,N-dimethylformamide was added. The mixture was stirred for 30 min under an argon atmosphere, and then 14 mL of triethylamine was added. The mixture was heated to 80 °C and reacted for 48 h to obtain the photocatalyst (BCz-AQ), the chemical structure of which is shown below:

[0047]

[0048] Comparative Example 1

[0049] A photocatalyst (Cz-AQ) can be prepared by the following method:

[0050] 100 mg of 3,6-dibromo-9-(2-ethylhexyl)-9H-carbazole, 79 mg of 2,6-diethynylanthraquinone from Example 2, 10.8 mg of bis(triphenylphosphine)palladium chloride, and 2.9 mg of cuprous iodide were placed in a flask, and 14 mL of N,N-dimethylformamide was added. The mixture was stirred for 30 min under an argon atmosphere, and then 14 mL of triethylamine was added. The mixture was heated to 80 °C and reacted for 48 h to obtain the photocatalyst (Cz-AQ), the chemical structure of which is shown below:

[0051]

[0052] Performance testing

[0053] (1) Characterization of photocatalysts

[0054] The X-ray diffraction patterns of photocatalyst BCz-AQ in Example 3 and photocatalyst Cz-AQ in Comparative Example 1 are as follows: Figure 1 As shown, the Fourier transform infrared spectrum is as follows: Figure 2 As shown, the solid-state NMR spectrum is as follows Figure 3 As shown, the TEM image is as follows Figure 4 As shown, the ultraviolet diffuse reflectance spectrum is as follows: Figure 5 As shown.

[0055] according to Figure 1 It can be observed that the XRD patterns of both photocatalysts BCz-AQ and Cz-AQ exhibit a single broad peak, originating from the interlayer stacking of the polymers, indicating that both photocatalysts BCz-AQ and Cz-AQ are in an amorphous state. Figure 2 The infrared spectrum shows that at 1670 cm⁻¹ -1 and 2200cm -1 The presence of characteristic peaks corresponding to C=O and C≡C at the locations indicates that the carbazole monomer reacted with the anthraquinone monomer.

[0056] according to Figure 3 As can be seen, the photocatalyst BCz-AQ exhibits a clear carbonyl carbon signal at 180 ppm and an alkynyl carbon signal at 90 ppm; simultaneously, according to... Figure 3b. It can be found that the photocatalyst Cz-AQ not only shows a clear carbonyl carbon signal at 180 ppm and an alkynyl carbon signal at 90 ppm, but also shows alkyl carbon signals in the carbazole side chain at 12 ppm and 37 ppm, which indicates that the photocatalysts BCz-AQ with the structure shown in Formula I and Cz-AQ with the structure shown in Formula II have been successfully synthesized.

[0057] according to Figure 4 As can be seen from a, the photocatalyst BCz-AQ has a layered structure, which is beneficial for improving photon utilization and achieving good catalytic effect under low light intensity; therefore, Figure 4 As shown in b, the morphology of the photocatalyst Cz-AQ is similar to that of BCz-AQ, both being layered structures. According to... Figure 5 It can be seen that both photocatalysts BC-AQ and Cz-AQ absorb light in the visible region, indicating that BC-AQ and Cz-AQ have similar light-harvesting capabilities in the visible region.

[0058] (2) Photocatalytic activity test

[0059] Test Method 1: Add 2 mg of photocatalyst (BCz-AQ or Cz-AQ) to 20 mL of phenol solution (10 ppm), and react in the dark for 30 min to reach adsorption equilibrium; then place it under a 300 W xenon lamp (light intensity 100 mW / cm²). 2 The reaction was carried out under light irradiation, with 500 μL samples taken every 10 minutes. The collected reaction solution was filtered through a 0.22 μm organic filter membrane, and the phenol degradation efficiency, hydrogen peroxide yield, and total organic carbon removal rate of the photocatalyst were tested. The test results were... Figure 6 As shown.

[0060] Test Method 2: Add 2 mg of photocatalyst (BCz-AQ or Cz-AQ) and 2 mg of K-FeOCl to 20 mL of phenol solution (10 ppm), and react in the dark for 30 min to reach adsorption equilibrium; then place it under a 300 W xenon lamp (light intensity 100 mW / cm²). 2 The reaction was carried out under light irradiation, with 500 μL samples taken every 10 minutes. The collected reaction solution was filtered through a 0.22 μm organic filter membrane, and the phenol degradation efficiency and total organic carbon removal rate of the photocatalyst + K-FeOCl were tested. The test results are as follows: Figure 6 As shown.

[0061] according to Figure 6As can be seen, the phenol degradation efficiency of photocatalyst BCz-AQ is higher than that of photocatalyst Cz-AQ, reaching 72% within 30 minutes, significantly higher than that of photocatalyst Cz-AQ (45%). Furthermore, it was observed that both BCz-AQ and Cz-AQ, when combined with K-FeOCl, contribute to improved phenol degradation efficiency. However, the combination of BCz-AQ and K-FeOCl results in a significantly higher phenol degradation efficiency, indicating a synergistic effect between BCz-AQ and K-FeOCl.

[0062] according to Figure 6 b. It can be found that the mineralization rate of the photocatalyst BCz-AQ (65%) is not only higher than that of Cz-AQ (17%), but its mineralization rate after combining with K-FeOC is as high as 95%. This indicates that the photocatalytic self-Fenton catalytic system formed by combining BCz-AQ with K-FeOCl can effectively improve the mineralization rate of organic pollutants.

[0063] according to Figure 6 As can be seen from c, in the absence of pollutants, the H2O2 yield of photocatalyst BCz-AQ (3956 μmol / (g·h)) is higher than that of Cz-AQ (1960 μmol / (g·h)), indicating that photocatalyst BCz-AQ has better photocatalytic performance in H2O2 synthesis. Furthermore, it can be found that during the pollutant degradation process, the H2O2 yield of photocatalyst BCz-AQ can be increased to 5364 μmol / (g·h), indicating that photocatalyst BCz-AQ can effectively improve the H2O2 yield. In addition, according to... Figure 6 It can be found that the photocatalytic self-Fenton catalytic system formed by the combination of BCz-AQ and K-FeOCl can still maintain a degradation efficiency of nearly 100% even after 10 cycles of degradation, indicating that the catalytic system has excellent stability.

[0064] (3) Reactive species test

[0065] Test method: 2 mg of photocatalyst BCz-AQ was added to 20 mL of phenol solution (10 ppm) and reacted in the dark for 30 min to reach adsorption equilibrium; then deferoxamine methanesulfonate (DFO), disodium EDTA-2Na, isopropanol (IPA), superoxide dismutase (SOD), histidine, and potassium dichromate were added as OCORs, holes, hydroxyl radicals (·OH), and superoxide radicals (·O) respectively. 2- Singlet oxygen () 1 O2) and an electron sacrificial agent were then placed in a 300W xenon lamp (illuminance 100mW / cm²). 2The reaction was carried out under light irradiation, with 500 μL samples taken every 10 minutes. The collected reaction solution was filtered through a 0.22 μm organic filter membrane, and the phenol degradation efficiency of the photocatalyst was tested to evaluate the contribution of different active species to the degradation efficiency. The test results... Figure 7 As shown.

[0066] according to Figure 7 As can be seen from a, in the BCz-AQ pollutant degradation process, the degradation efficiency significantly decreased only after the addition of DFO, indicating that the main reactive species in the degradation process are OCORs rather than traditional reactive oxygen species. Meanwhile, from Figure 7 b. It can be observed that, in addition to the inhibitory effect of DFO, the addition of IPA and histidine also has a significant inhibitory effect after the addition of K-FeOCl. This also indicates that the active species in the degradation reaction process change from OCORs to OCORs, ·OH and 1 O2 synergistic effect.

[0067] (4) Concentration and lifetime of OCORs: in-situ electron paramagnetic resonance testing

[0068] The testing method was as follows: 20 mg of photocatalyst powder (BCz-AQ) was placed in a quartz tube, and the initial OCORS signal intensity was collected; then, a 300 W xenon lamp (illuminance 100 mW / cm²) was used. 2 The reaction was conducted under illumination, with spectral scanning performed every 5 minutes. Once the signal intensity reached its maximum, the 300W xenon lamp was turned off, and spectral scanning continued every 5 minutes to monitor the OCRs lifetime decay process. The test results are as follows: Figure 8 As shown.

[0069] according to Figure 8 As can be seen from a, after photoexcitation, the amount of OCRs generated begins to increase, and the OCRs concentration reaches its maximum within 10 minutes; from Figure 8 b. It can be observed that the intensity of OCRs gradually decreases after the light is removed. Fitting the entire OCR intensity change process yields the following results: Figure 8 As shown in c, the concentration of OCORs reaches its maximum within 10 minutes under illumination, and the intensity decay process can continue for nearly 10 minutes after the illumination is removed, indicating that the stable long-lifetime characteristics of OCORs can provide sufficient time for the diffusion of pollutants. At the same time, it also indirectly shows that OCORs reduce the attack on the photocatalyst itself and can improve the stability of the photocatalytic self-Fenton catalytic system formed by the combination of BCz-AQ and K-FeOCl.

[0070] (4) Degradation test of organic pollutants under different light intensities

[0071] Test Method 1: Add 2 mg of photocatalyst BCz-AQ and 2 mg of photocatalyst BCz-AQ + 2 mg of K-FeOCl to 20 mL of phenol solution (10 ppm), respectively, and react in the dark for 30 min to reach adsorption equilibrium; then place them under an LED light (light intensity 10 mW / cm²). 2 The reaction was carried out, and 500 μL samples were taken every 30 minutes. The collected reaction solution was filtered through a 0.22 μm organic filter membrane, and the phenol degradation efficiency and mineralization rate of BCz-AQ and BCz-AQ+K-FeOCl were tested respectively. The test results are as follows: Figure 9 As shown in a. According to Figure 9 It can be observed that, compared to BCz-AQ, BCz-AQ+K-FeOCl exhibits better performance under 10 mW / cm² illumination. 2 It still exhibits higher degradation efficiency and mineralization rate even under low light conditions.

[0072] (5) Anti-interference capability test

[0073] Test Method 1: Add 2 mg of photocatalyst BCz-AQ + 2 mg of K-FeOCl to 20 mL of phenol solution (10 ppm), and adjust the pH of the solution to 3, 5, 7, and 9 respectively. React in the dark for 30 min to reach adsorption equilibrium; then place it under xenon lamp illumination (light intensity 100 mW / cm²). 2 The reaction was carried out, and 500 μL samples were taken every 30 minutes. The collected reaction solution was filtered through a 0.22 μm organic filter membrane, and the phenol degradation efficiency of BCz-AQ+K-FeOCl was tested. The test results are as follows: Figure 9 As shown in b.

[0074] Test Method 2: Add 2 mg of photocatalyst BCz-AQ + 2 mg of K-FeOCl to 20 mL of phenol solution (10 ppm), and add 10 mM NaCl, Na2SO4, and NaNO3 respectively. React in the dark for 30 min to reach adsorption equilibrium; then place it under xenon lamp illumination (light intensity 100 mW / cm²). 2 The reaction was carried out, and 500 μL samples were taken every 30 minutes. The collected reaction solution was filtered through a 0.22 μm organic filter membrane, and the phenol degradation efficiency of BCz-AQ+K-FeOCl was tested. The test results are as follows: Figure 9 As shown in c.

[0075] Depend on Figure 9 b and Figure 9 c shows that BCz-AQ+K-FeOCl also has excellent anti-interference ability, within the pH range of 3-9 and with multiple anions (Cl... - SO4 2-NO3 - Even in the presence of ), it still maintains a high degradation efficiency.

[0076] (6) Simulate real-world environment testing

[0077] Test method: 2 mg of photocatalyst BCz-AQ + 2 mg of K-FeOCl were added to 20 mL of actual water (River 1, River 2) and placed in a dark environment for 30 min to reach adsorption equilibrium; then, it was placed on a rooftop to simulate the light conditions of a real natural environment (e.g., Figure 10 As shown in b), a degradation test was conducted, and the test results were... Figure 10 As shown in a. According to Figure 10 As can be seen from a, under simulated real natural environment conditions, even if the ambient light intensity is weak and fluctuates, it can still degrade rapidly and maintain excellent anti-interference ability in complex actual water environments.

[0078] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for mineralizing organic pollutants in surface water, characterized in that, The mineralization of organic pollutants is achieved by mixing photocatalysts, heterogeneous Fenton catalysts, and organic pollutants, followed by illumination. The chemical structural formula of the photocatalyst is shown in Formula I, where n ≥ 1. Formula I.

2. The method for mineralizing organic pollutants in surface water according to claim 1, characterized in that, The mass ratio of the photocatalyst to the heterogeneous Fenton catalyst is 1:(0.5~1.5).

3. The method for mineralizing organic pollutants in surface water according to claim 2, characterized in that, The heterogeneous Fenton catalyst is at least one of K-FeOCl, FeOCl, iron hydroxide, ferrous sulfate, or iron phosphide.

4. The method for mineralizing organic pollutants in surface water according to claim 1, characterized in that, The intensity of the light is ≤100mW / cm 2 .

5. The method for mineralizing organic pollutants in surface water according to claim 4, characterized in that, The intensity of the light is ≤10mW / cm 2 .

6. The method for mineralizing organic pollutants in surface water according to claim 1, characterized in that, The concentration of the photocatalyst is 0.05~0.2 g / L, and the concentration of the heterogeneous Fenton catalyst is 0.05~0.3 g / L.

7. The method for mineralizing organic pollutants in surface water according to claim 1, characterized in that, The organic pollutants have a pH of 3 to 9.

8. The method for mineralizing organic pollutants in surface water according to claim 1, characterized in that, The photocatalyst is prepared by the following method: The product is obtained by coupling reaction of 3,3',6,6'-tetrabromo-9,9'-biscarbazole and 2,6-diethynylanthraquinone in an organic solvent under an inert atmosphere.

9. The method for mineralizing organic pollutants in surface water according to claim 8, characterized in that, The molar ratio of 3,3',6,6'-tetrabromo-9,9'-biscarbazole to 2,6-diethynylanthraquinone is 1:(1.5~2.5).

10. The method for mineralizing organic pollutants in surface water according to claim 8, characterized in that, The coupling reaction of the scallion head is carried out at a temperature of 80~90℃ for 36~48h.

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