Photocatalytic membrane for inhibiting microcystis aeruginosa as well as preparation method and application of photocatalytic membrane

Abstract

The invention discloses a photocatalytic membrane for inhibiting microcystis aeruginosa as well as a preparation method and application of the photocatalytic membrane, and belongs to the technical field of algal bloom pollution treatment. According to the photocatalytic membrane for inhibiting the microcystis aeruginosa, Bi2WO6 or CQDs / Bi2WO6 powder is used as a photocatalyst, and cellulose acetate is used as a membrane molecular skeleton to construct the photocatalytic membrane; the Bi2WO6 photocatalytic membrane or the CQDs / Bi2WO6 photocatalytic membrane is obtained. The photocatalytic membrane prepared by the method has the advantages that the material can be recycled, and the pollution to a water body is small; the Bi2WO6 or CQDs / Bi2WO6 photocatalytic membrane is placed in a microcystis aeruginosa solution, growth of microcystis aeruginosa can be effectively inhibited for a long time, and the algae inhibition rate can reach 55% or above; and the prepared Bi2WO6 or CQDs / Bi2WO6 photocatalytic membrane can be repeatedly used for carrying out an algae inhibition experiment for multiple times, and the stable algae inhibition rate is kept.

Description

Technical Field

[0001] The invention relates to a photocatalytic film for inhibiting Microcystis aeruginosa and a preparation method and application thereof, belonging to the technical field of water bloom pollution control. Background Art

[0002] In recent years, global warming and eutrophication of water bodies have led to frequent harmful algal blooms. As the main algae growing on the surface of water bodies, the rapid growth of cyanobacteria reduces the light transmittance of the water body, inhibits the photosynthesis of aquatic organisms, and reduces the oxygen content of the water body, thus affecting the normal growth of aquatic organisms. In particular, Microcystis aeruginosa has become the main cause of red tides in freshwater bodies due to its wide distribution. The microcystin toxins it releases pose a serious threat to the nervous and renal systems of animals and even humans. At present, common methods for removing Microcystis aeruginosa from water bodies include physical methods (Wu X, Joyce EM, Mason TJ, Water Res. 2012, 46 (9): 2851-2858.), chemical methods (Park J, Yang B, JangM, et al., Chem. Eng. J. 2019, 366: 423-432.) and biological methods (Tan K, Huang Z, Ji R, et al., Microbiology 2019, 165 (6): 587-592.). Although physical methods are effective, they can only temporarily solve the problem and cannot fundamentally solve the algal bloom problem. In addition, the cost and maintenance costs are high, and the treatment effect on microalgae particles is not good. Chemical methods may produce by-products in the process of treating algal blooms, posing potential risks to the aquatic ecosystem. Biological treatment takes a long time and has high requirements for environmental conditions (Fan GD, Cai CJ, Chen ZY, et al., J Hazard Mater., 2023, 441: 129932.). In recent years, photocatalysts have been reported to show application prospects in controlling harmful algal blooms (Sun SQ, Tang QX, Yu TP, et al., Environ. Res., 2022, 215:114216.). Photocatalytic technology directly uses solar energy as an energy source, which is environmentally friendly, low-cost and highly efficient. However, the biggest problem facing the application of photocatalytic technology in algae removal is that powdered nanomaterials are difficult to recycle, causing secondary pollution to the water environment. In addition, photocatalysts are prone to aggregation and precipitation when injected into water bodies, thereby limiting the full contact between algae cells and photocatalysts. Therefore, immobilizing powdered photocatalytic materials is a necessary condition for the practical application of photocatalysts in algae inactivation. Summary of the invention

[0003] The present invention aims to provide a photocatalytic film for inhibiting Microcystis aeruginosa and a preparation method and application thereof, which can effectively solve the problems of secondary pollution of water bodies caused by powder catalysts and difficulty in material recovery during the existing process of controlling algal blooms.

[0004] The present invention is based on Bi 2 WO 6 or CQDs / Bi 2 WO 6 Powder is used as a photocatalyst. First, bismuth tungstate (Bi 2 WO 6 ) as a photocatalyst, Bi 2 WO 6 The unique layered structure can effectively absorb visible light and provide sufficient sites for the reaction; secondly, in order to improve Bi 2 WO 6 To improve the utilization rate of light energy, composite carbon quantum dots (CQDs) are used to improve Bi 2 WO 6 The present invention uses cellulose acetate as the membrane molecular skeleton to construct the photocatalytic film, and Bi 2 WO 6 or CQDs / Bi 2 WO 6 The powder is evenly fixed to prevent the photocatalyst from agglomerating and precipitating after entering the water body, thereby ensuring sufficient contact between the algae cells and the photocatalyst.

[0005] The present invention provides a photocatalytic film for inhibiting Microcystis aeruginosa, using Bi 2 WO 6 or CQDs / Bi 2 WO 6 Powder was used as a photocatalyst, and cellulose acetate was used as a membrane molecular skeleton to construct a photocatalytic film; Bi 2 WO 6 Photocatalytic film or CQDs / Bi 2 WO 6 Photocatalytic film.

[0006] The present invention provides the above-mentioned Bi for inhibiting Microcystis aeruginosa 2 WO 6 The method for preparing a photocatalytic film comprises the following steps: Step 1: Bi(NO 3 ) 3 ·5H 2 O and Na 2 WO 6The mixture was dissolved in deionized water and stirred for 10 to 30 min. After the reaction was completed, it was washed with deionized water and anhydrous ethanol for several times, and then placed in a drying oven at 60 to 80 °C for 16 to 24 h to obtain Bi 2 WO 6 powder; Among them, Bi(NO 3 ) 3 ·5H 2 O and Na 2 WO 6 The molar ratio of Na 2 WO 6 The dosage ratio with deionized water is 0.68 ~ 6.6 mg / mL.

[0007] Step 2: Dissolve cellulose acetate in acetone and add photocatalyst Bi 2 WO 6 Powder, after ultrasonic treatment for 1 to 3 h, a cross-linked product was obtained; In the acetone solution of cellulose acetate, the concentration of cellulose acetate is 0.033 ~ 0.2 g / mL, and the cellulose acetate and the photocatalyst Bi 2 WO 6 The mass ratio of the powder is 1.03 ~ 8.25.

[0008] Step 3: Add deionized water to the crosslinked product, shake it evenly, and then pour it into a petri dish with a diameter of 6 cm to dry to obtain Bi 2 WO 6 Photocatalytic film.

[0009] The temperature of the deionized water is 60 to 80°C, and the amount ratio of the deionized water to the cross-linked product is 0.47 to 1.42 mL / g.

[0010] The present invention provides the above-mentioned CQDs / Bi for inhibiting Microcystis aeruginosa 2 WO 6 The method for preparing a photocatalytic film comprises the following steps: Step 1: Bi(NO 3 ) 3 ·5H 2 O and Na 2 WO 6 The mixture was mixed in deionized water and stirred for 10 to 30 min. After adding CQDs powder, the mixture was ultrasonicated for 30 to 60 min and then placed in a high-pressure reactor for hydrothermal reaction for 16 to 24 h. After the reaction, the mixture was washed with deionized water and anhydrous ethanol for several times and then placed in a drying oven at 60 to 80 °C for 16 to 24 h to obtain CQDs / Bi 2 WO6 powder; Among them, Bi(NO 3 ) 3 ·5H 2 O and Na 2 WO 6 The molar ratio of Na 2 WO 6 The dosage ratio of CQDs to deionized water was 0.68 ~ 6.6 mg / mL; 3 ) 3 ·5H 2 The mass ratio of O is 0.003 ~ 0.124.

[0011] Step 2: Dissolve cellulose acetate in acetone and add photocatalyst CQDs / Bi 2 WO 6 Powder, after ultrasonication for 1 to 3 hours, a cross-linked product is obtained; In the acetone solution of cellulose acetate, the concentration of cellulose acetate is 0.033 ~ 0.2 g / mL, and the cellulose acetate and photocatalyst CQDs / Bi 2 WO 6 The mass ratio of the powder is 1.03 ~ 8.25.

[0012] Step 3: Add deionized water to the crosslinked product, shake it evenly, and then pour it into a petri dish with a diameter of 6 cm to dry, thereby obtaining CQDs / Bi 2 WO 6 Photocatalytic film.

[0013] The temperature of the deionized water is 60 to 80°C, and the amount ratio of the deionized water to the cross-linked product is 0.35 to 1.68 mL / g.

[0014] The present invention provides the above-mentioned Bi for inhibiting Microcystis aeruginosa 2 WO 6 or CQDs / Bi 2 WO 6 Application of photocatalytic film in inhibiting the growth of Microcystis aeruginosa.

[0015] In the above application, the obtained Bi 2 WO 6 or CQDs / Bi 2 WO 6 The photocatalytic film is placed in a solution of Microcystis aeruginosa to inhibit its growth under natural light. The concentration of the solution is 4×10 6 ~ 22×10 6 cells / mL.

[0016] Beneficial effects of the present invention: (1) The photocatalytic film prepared by the present invention can solve the secondary pollution of water bodies caused by algaecides in traditional algae removal methods, and has the advantages of being recyclable and cyclical, and having little pollution to water bodies; (2) The photocatalyst is evenly fixed on cellulose acetate and will not enter the water body, thus preventing the material from causing water pollution; (3) Change Bi 2 WO 6 or CQDs / Bi 2 WO 6 The photocatalytic film was placed in the algae solution of Microcystis aeruginosa, which could effectively inhibit the growth of Microcystis aeruginosa for a long time, and the inhibition rate could reach more than 55%. 2 WO 6 or CQDs / Bi 2 WO 6 The photocatalytic film can be used to repeatedly perform algae inhibition experiments and maintain a stable algae inhibition rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Bi prepared in Examples 1 and 2 of the present invention 2 WO 6 、CQDs / Bi 2 WO 6 XRD pattern of .

[0018] Figure 2 Bi prepared in Examples 1 and 2 of the present invention 2 WO 6 、CQDs / Bi 2 WO 6 The inhibition rate of photocatalytic film on Microcystis aeruginosa under natural light. C is the concentration of algae solution, C 0 is the initial concentration of algae solution. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. Example 1

[0020] (1) Add 485 mg Bi(NO 3 ) 3 ·5H 2 O and 165 mg Na 2 WO 6 Mixed in 100 mL of deionized water, stirred for 15 min, and then placed in a high-pressure reactor for hydrothermal reaction for 24 h. After the reaction, it was washed with deionized water and anhydrous ethanol several times, and then placed in a drying oven at 60 ° C for 24 h to obtain Bi 2WO 6 powder.

[0021] (2) Dissolve 1 g of cellulose acetate in 10 mL of acetone and add 599 mg of Bi 2 WO 6 The cross-linked product was obtained after ultrasonic treatment for 2 h.

[0022] (3) Add 1 mL of 80 ℃ deionized water to the above cross-linked product, shake it evenly, and pour it into a Petri dish with a diameter of 6 cm to dry to obtain Bi 2 WO 6 Photocatalytic film.

[0023] (4) Microcystis aeruginosa was selected as the target algae solution, with a concentration of 6×10 6 cells / mL, take 100 mL of algae solution into a 250 mL beaker. Add the Bi 2 WO 6 Photocatalytic film, the algae liquid was placed under natural light, the experimental site was 37°44'47.537"N, 112°43'21.504"E, the illumination period was from August 9, 2024 to September 23, 2024, the illumination time was 6:00 am-19:30 pm every day, excluding rainy days, the actual number of days of illumination was 24. After the end of each day's illumination, the algae liquid was sampled and the absorbance was measured to characterize the concentration change of the algae liquid. The experimental results are as follows Figure 2 The final algae inhibition rates are listed in Table 1. Example 2

[0024] (1) Add 485 mg Bi(NO 3 ) 3 ·5H 2 O and 165 mg Na 2 WO 6 The mixture was mixed in 100 mL of deionized water, 15 mg of CQDs powder was added, and then ultrasonicated for 10 min. After stirring for 15 min, the mixture was placed in a high-pressure reactor for hydrothermal reaction for 24 h. After the reaction, it was washed with deionized water and anhydrous ethanol several times, and then placed in a drying oven at 60 °C for 24 h to obtain CQDs / Bi 2 WO 6 powder.

[0025] (2) Dissolve 1 g of cellulose acetate in 10 mL of acetone and add 599 mg of CQDs / Bi 2 WO 6 The cross-linked product was obtained after ultrasonic treatment for 2 h.

[0026] (3) Add 1 mL of 80 °C deionized water to the cross-linked product, shake it evenly, and pour it into a 6 cm diameter Petri dish to dry to obtain CQDs / Bi 2 WO 6 Photocatalytic film.

[0027] (4) Microcystis aeruginosa was selected as the target algae solution, with a concentration of 6×10 6 cells / mL, take 100 mL of algae solution into a 250 mL beaker. Add the CQDs / Bi 2 WO 6 Photocatalytic film, the algae liquid was placed under natural light, the experimental site was 37°44'47.537"N, 112°43'21.504"E, the illumination period was from August 9, 2024 to September 23, 2024, the illumination time was 6:00 am-19:30 pm every day, excluding rainy days, the actual number of days of illumination was 24. After the end of each day's illumination, the algae liquid was sampled and the absorbance was measured to characterize the concentration change of the algae liquid. The experimental results are as follows Figure 2 The final algae inhibition rates are listed in Table 1.

[0028] By the attached Figure 1 It can be seen that after adding CQDs, CQDs / Bi 2 WO 6 The diffraction peaks of Bi 2 WO 6 There is no obvious change compared with the previous study, indicating that the amount of CQDs added is small and 2 WO 6 Evenly distributed on the surface.

[0029] By the attached Figure 2 It can be seen that compared with Example 1, the addition of tiny CQDs makes CQDs / Bi 2 WO 6 The algae inhibition rate increased by 35.49%. Example 3

[0030] (1) Add 485 mg Bi(NO 3 ) 3 ·5H 2 O and 165 mg Na 2 WO 6 Mixed in 100 mL of deionized water, stirred for 15 min, and then placed in a high-pressure reactor for hydrothermal reaction for 24 h. After the reaction, it was washed with deionized water and anhydrous ethanol several times, and then placed in a drying oven at 60 ° C for 24 h to obtain Bi 2 WO 6 powder.

[0031] (2) Dissolve 1 g of cellulose acetate in 10 mL of acetone and add 300 mg of Bi 2 WO 6 The cross-linked product was obtained after ultrasonic treatment for 2 h.

[0032] (3) Add 1 mL of 80 ℃ deionized water to the above cross-linked product, shake it evenly, and pour it into a Petri dish with a diameter of 6 cm to dry to obtain Bi 2 WO 6 Photocatalytic film.

[0033] (4) Microcystis aeruginosa was selected as the target algae solution, with a concentration of 6×10 6 cells / mL, take 100 mL of algae solution into a 250 mL beaker. Add the Bi 2 WO 6 Photocatalytic film, the algae liquid was placed under natural light, the experimental site was 37°44'47.537"N, 112°43'21.504"E, the illumination period was from August 9, 2024 to September 23, 2024, the illumination time was 6:00 am-19:30 pm every day, excluding rainy days, the actual illumination days were 24. After the end of each day's illumination, the algae liquid absorbance was sampled and measured to characterize the concentration change of the algae liquid, and the final algae inhibition rate is listed in Table 1. Example 4

[0034] (1) Add 485 mg Bi(NO 3 ) 3 ·5H 2 O and 165 mg Na 2 WO 6 The mixture was mixed in 100 mL of deionized water, 5 mg of CQDs powder was added, and then ultrasonicated for 10 min. After stirring for 15 min, it was placed in a high-pressure reactor for hydrothermal reaction for 24 h. After the reaction, it was washed with deionized water and anhydrous ethanol several times, and then placed in a drying oven at 60 °C for 24 h to obtain CQDs / Bi 2 WO 6 powder.

[0035] (2) Dissolve 1 g of cellulose acetate in 10 mL of acetone and add 599 mg of CQDs / Bi 2 WO 6 The cross-linked product was obtained after ultrasonic treatment for 2 h.

[0036] (3) Add 1 mL of 80 °C deionized water to the cross-linked product, shake it evenly, and pour it into a 6 cm diameter Petri dish to dry to obtain CQDs / Bi 2 WO 6 Photocatalytic film.

[0037] (4) Microcystis aeruginosa was selected as the target algae solution, with a concentration of 6×10 6 cells / mL, take 100 mL of algae solution into a 250 mL beaker. Add the CQDs / Bi 2 WO 6 Photocatalytic film, the algae liquid was placed under natural light, the experimental site was 37°44'47.537"N, 112°43'21.504"E, the illumination period was from August 9, 2024 to September 23, 2024, the illumination time was 6:00 am-19:30 pm every day, excluding rainy days, the actual illumination days were 24. After the end of each day's illumination, the algae liquid absorbance was sampled and measured to characterize the concentration change of the algae liquid, and the final algae inhibition rate is listed in Table 1.

[0038] The drugs and reagents used in the above examples are all analytically pure. 2 WO 6 、CQDs / Bi 2 WO 6 The algae inhibition rate of the photocatalytic film in different embodiments.

[0039] Table 1 Algae inhibition rate of the photocatalytic films of Examples 1 to 4 .

Claims

1. A photocatalytic film for inhibiting Microcystis aeruginosa, characterized in that: A photocatalytic film is constructed by using Bi2WO6 or CQDs / Bi2WO6 powder as a photocatalyst and cellulose acetate as a membrane molecular skeleton; a Bi2WO6 photocatalytic film or a CQDs / Bi2WO6 photocatalytic film is obtained.

2. The photocatalytic film for inhibiting Microcystis aeruginosa according to claim 1, characterized in that: In the Bi2WO6 photocatalytic film, the mass ratio of cellulose acetate to photocatalyst Bi2WO6 powder is 1.03 ~ 8.

25.

3. The photocatalytic film for inhibiting Microcystis aeruginosa according to claim 1, characterized in that: In the CQDs / Bi2WO6 photocatalytic film, the mass ratio of cellulose acetate to photocatalyst CQDs / Bi2WO6 powder is 1.03 ~ 8.

25.

4. A method for preparing a photocatalytic film for inhibiting Microcystis aeruginosa according to claim 1 or 2, characterized in that The following steps are involved: Step 1: Mix Bi(NO3)3·5H2O and Na2WO6 and dissolve them in deionized water, stir for 10 to 30 min, wash with deionized water and anhydrous ethanol several times after the reaction, and then place in a drying oven at 60 to 80 °C for 16 to 24 h to obtain Bi2WO6 powder; Step 2: dissolving cellulose acetate in acetone, adding photocatalyst Bi2WO6 powder, and ultrasonicating for 1 to 3 h to obtain a cross-linked product; Step 3: Add deionized water to the cross-linked product, shake it evenly, pour it into a culture dish and dry it to obtain a Bi2WO6 photocatalytic film.

5. The method for preparing a photocatalytic film for inhibiting Microcystis aeruginosa according to claim 4, characterized in that: In step 1, the molar ratio of Bi(NO3)3·5H2O to Na2WO6 is 0.5 to 4; the dosage ratio of Na2WO6 to deionized water is 0.68 to 6.6 mg / mL.

6. The method for preparing a photocatalytic film for inhibiting Microcystis aeruginosa according to claim 4, characterized in that: In step 2, the concentration of cellulose acetate in the acetone solution of cellulose acetate is 0.033 ~ 0.2 g / mL, and the mass ratio of cellulose acetate to photocatalyst Bi2WO6 powder is 1.03 ~ 8.25; in step 3, the temperature of deionized water is 60 ~ 80 ° C, and the amount ratio of deionized water to cross-linked material is 0.47 ~ 1.42 mL / g.

7. A method for preparing a photocatalytic film for inhibiting Microcystis aeruginosa according to claim 1 or 3, characterized in that The following steps are involved: Step 1: Mix Bi(NO3)3·5H2O and Na2WO6 in deionized water, stir for 10 to 30 min, add CQDs powder and ultrasonicate for 30 to 60 min, then place in a high-pressure reactor for hydrothermal reaction for 16 to 24 h; after the reaction, wash with deionized water and anhydrous ethanol several times, then place in a drying oven at 60 to 80 °C and dry for 16 to 24 h to obtain CQDs / Bi2WO6 powder; Step 2: dissolving cellulose acetate in acetone, adding photocatalyst CQDs / Bi2WO6 powder, and ultrasonicating for 1 to 3 h to obtain a cross-linked product; Step 3: Add deionized water to the cross-linked product, shake it evenly, pour it into a culture dish with a diameter of 6 cm and dry it to obtain a CQDs / Bi2WO6 photocatalytic film.

8. The method for preparing a photocatalytic film for inhibiting Microcystis aeruginosa according to claim 7, characterized in that: In step 1, the molar ratio of Bi(NO3)3·5H2O to Na2WO6 is 0.5 to 4; the dosage ratio of Na2WO6 to deionized water is 0.68 to 6.6 mg / mL; and the mass ratio of CQDs to Bi(NO3)3·5H2O is 0.003 to 0.

124.

9. The method for preparing a photocatalytic film for inhibiting Microcystis aeruginosa according to claim 7, characterized in that: In step 2, the concentration of cellulose acetate in the acetone solution of cellulose acetate is 0.033 ~ 0.2 g / mL, and the mass ratio of cellulose acetate to photocatalyst CQDs / Bi2WO6 powder is 1.03 ~ 8.25; in step 3, the temperature of deionized water is 60 ~ 80 ° C, and the amount ratio of deionized water to cross-linked material is 0.35 ~ 1.68 mL / g.

10. Use of the photocatalytic film for inhibiting Microcystis aeruginosa according to any one of claims 1 to 3 in inhibiting the growth of Microcystis aeruginosa.

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