A dual-function algaecide for inhibiting the growth of harmful algae and its preparation method

Abstract

The present invention discloses a bifunctional algaecide for inhibiting the growth of harmful algae and a preparation method thereof, and belongs to the technical field of water pollutant treatment. The method of the present invention introduces an EDU functional group while condensing SiO2-COOH with CP through an EDCI-mediated condensation method, thereby obtaining a bifunctional algaecide SiO2@EDU@CP with flocculation / photocatalysis. Under the irradiation of a 23W white light lamp or even sunlight, SiO2@EDU@CP can generate superoxide radicals and holes to inhibit the growth of Microcystis aeruginosa. Through reasonable optimization of reaction conditions, the method can achieve an inhibition rate of up to 94.8% on Microcystis aeruginosa within 740 minutes of reaction under light, and can also inhibit the growth of cyanobacteria in the actual environment of Taihu Lake. The SiO2@EDU@CP has a very broad application prospect as an algaecide that can inhibit cyanobacteria in a broad spectrum.

Description

Technical Field

[0001] The invention relates to a dual-function algaecide for inhibiting the growth of harmful algae and a preparation method thereof, belonging to the technical field of water pollutant treatment. Background Art

[0002] Algal blooms and the large amounts of algal toxins produced during their metabolism by the dominant algae are extremely harmful to the aquatic environment, animals, and even humans. Therefore, effectively controlling the excessive growth of the dominant algae that cause algal blooms is the primary task of algal bloom management.

[0003] Methods for controlling harmful algae can be categorized into physical, chemical, and biological methods. Photocatalysis offers advantages such as ease of availability, low cost, wide range of pollutant removal, mild reaction conditions, and strong oxidative capacity, making it a promising method for pollutant degradation. However, direct use of organic photocatalysts for inhibiting cyanobacteria still presents challenges such as low degradation efficiency and potential secondary pollution. Therefore, the development of a versatile, highly efficient photocatalytic algaecide that addresses this potential secondary pollution issue is crucial. Summary of the Invention

[0004] In response to the current problem of lack of economical and effective methods for controlling harmful algae such as cyanobacteria blooms, the present invention provides an application of a dual-function algaecide in inhibiting the growth of harmful algae.

[0005] The present invention provides a preparation method of a bifunctional algaecide SiO2@EDU@CP. The method comprises the following steps: subjecting SiO2-COOH, EDCI and cercosporin to a condensation reaction to obtain the bifunctional algaecide SiO2@EDU@CP.

[0006] In one embodiment of the present invention, the mass ratio of cercosporin to SiO2-COOH is 1:(15-20).

[0007] In one embodiment of the present invention, the particle size of SiO2-COOH is 500 nm.

[0008] In one embodiment of the present invention, the molar ratio of cercosporin to EDCI is 1:(1-20).

[0009] In one embodiment of the present invention, HOBt and DMAP are further added to participate in the condensation reaction.

[0010] In one embodiment of the present invention, the mass ratio of cercosporin to HOBt is 1:(30-50); specifically, 1:40.

[0011] In one embodiment of the present invention, the mass ratio of cercosporin to DMAP is 1:(15-20); specifically, it can be 1:18.

[0012] In one embodiment of the present invention, the condensation reaction is carried out in an organic solvent; the organic solvent is tetrahydrofuran, dichloromethane, dimethylformamide, ethyl acetate or acetonitrile.

[0013] In one embodiment of the present invention, the concentration of SiO2-COOH relative to the organic solvent is 10-20 mg / mL.

[0014] In one embodiment of the present invention, the condensation reaction time is 5-48 hours.

[0015] In one embodiment of the present invention, the condensation reaction is carried out under stirring conditions at a rotation speed of 100-250 rpm.

[0016] In one embodiment of the present invention, the method further comprises: after the condensation reaction is completed, centrifuging to remove the solvent, washing, and freeze-drying.

[0017] In one embodiment of the present invention, the washing method is to wash with methanol and dichloromethane respectively until the liquid is colorless, and then wash with dd H2O, wherein the volume ratio of MeOH:DCM is 1:(0.5-10).

[0018] The present invention provides a dual-function algaecide prepared by the above preparation method.

[0019] The present invention provides the use of the dual-function algaecide SiO2@EDU@CP in inhibiting the growth of harmful algae.

[0020] In one embodiment of the present invention, the application process includes: adding the dual-functional algaecide SiO2@EDU@CP to a water body containing harmful algae, stirring, allowing to stand, and then placing it under visible light for treatment.

[0021] In one embodiment of the present invention, the visible light is selected from: 5-23W white light lamp, 20W purple LED lamp, 20W blue LED lamp, 20W green LED lamp, and sunlight.

[0022] In one embodiment of the present invention, the added amount of SiO2@EDU@CP is 1-4 mg / mL.

[0023] In one embodiment of the present invention, the treatment time is 0-12 hours, and is not 0.

[0024] In one embodiment of the present invention, the harmful algae include any one or more of the following: Microcystis aeruginosa (FACHB-905), Anabaena (FACHB-82), Aphanizomenon flos-aquae (FACHB-1040), Oscillatoria (FACHB-528), Phytocystis aegypti (FACHB-920), and Taihu cyanobacteria.

[0025] In one embodiment of the present invention, the algae density in the water body containing harmful algae is 0.2-1.6×10 7 pieces / mL.

[0026] Beneficial effects:

[0027] (1) The dual-function algaecide SiO2@EDU@CP prepared by the present invention causes different harmful algae to flocculate after 20 minutes, and the sedimentation rate can reach about 80%. In particular, when inhibiting the growth of Microcystis aeruginosa, the sedimentation rate can reach 90%. At the same time, SiO2@EDU@CP can also improve the electron transfer efficiency and the separation efficiency of electron-hole pairs, thereby improving the efficiency of photocatalytic inhibition of harmful algae. Specifically, the dual-function algaecide SiO2@EDU@CP prepared by the present invention can inhibit different harmful algae with high inhibition efficiency. The inhibition rate for a variety of different harmful algae can reach about 80%, especially when inhibiting the growth of Microcystis aeruginosa, the inhibition rate can reach 90%.

[0028] (2) The synthesis of the dual-functional algaecide SiO2@EDU@CP in the present invention adopts a one-step synthesis method, and the preparation method is simple.

[0029] (3) Environmentally friendly: When the dual-functional algaecide of the present invention is used to inhibit harmful algae, only the dual-functional algaecide SiO2@EDU@CP is added during the reaction. The reaction is carried out under light. SiO2@EDU@CP is stable during the reaction, there is no leakage of CP, and no secondary pollution to the environment is caused.

[0030] (4) High efficiency and time saving: When using the catalyst of the present invention to degrade antibiotics, it is only necessary to put SiO2@EDU@CP into the harmful algae solution and then illuminate it under a 23W white light lamp or sunlight for 12 hours to effectively inhibit a variety of different harmful algae. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 These are the infrared spectra of CP, SiO2-COOH and SiO2@EDU@CP in Example 1.

[0032] Figure 2 This is an inverted fluorescence microscope image of SiO2@EDU@CP in Example 1.

[0033] Figure 3 Schematic diagram of the growth inhibition of Microcystis aeruginosa by SiO2@EDU@CP with different particle sizes.

[0034] Figure 4 Schematic diagram of the growth inhibition of Microcystis aeruginosa by adding different amounts of SiO2@EDU@CP.

[0035] Figure 5 Schematic diagram of the SiO2@EDU@CP inhibition of Microcystis aeruginosa growth at different pH values.

[0036] Figure 6 Schematic diagram of the growth changes of Microcystis aeruginosa inhibited by SiO2@EDU@CP at different concentrations.

[0037] Figure 7 Schematic diagram of the appearance changes of SiO2@EDU@CP in inhibiting Microcystis aeruginosa at different times.

[0038] Figure 8 Schematic diagram of the oil immersion microscope images of SiO2@EDU@CP inhibiting Microcystis aeruginosa at different times

[0039] Figure 9 Schematic diagram of the changes in the TEM structure of Microcystis aeruginosa inhibited by SiO2@EDU@CP.

[0040] Figure 10 Schematic diagram of the implementation of SiO2@EDU@CP to inhibit Taihu algae under sunlight.

[0041] Figure 11 To detect the residual amount of CP in the reaction solution of outdoor sunlight experiment.

[0042] Figure 12 Schematic diagram of the preparation and application process of SiO2@EDU@CP of the present invention. DETAILED DESCRIPTION

[0043] The present invention is further illustrated below by way of examples.

[0044] The SiO2-COOH involved in the following examples was prepared by the following process:

[0045] In the first step, SiO2 is aminated. SiO2 (1 g), toluene (49 mL), APTES (1 mL), and triethylamine (0.15 mL) are added to a reaction flask and reacted in an oil bath at 110°C for 5 hours. After the reaction, the sample is cooled to room temperature, centrifuged to remove the toluene, washed five times with acetone, and dried in vacuo to obtain SiO2-NH2. SiO2-NH2 (3 g) is added to 100 mL of ethanol, and 7.5 g of glutaric anhydride is added continuously. The mixture is stirred at 37°C for 3 hours until the reaction is complete. The ethanol is removed by centrifugation and the unreacted glutaric anhydride is removed by washing five times with 0.1 M NaCl solution. The solid obtained by centrifugation is freeze-dried in vacuo to obtain SiO2-COOH, the carboxyl content of which can be determined by back titration.

[0046] [Example 1] Preparation of dual-function algaecide SiO2@EDU@CP

[0047] SiO2@EDU@CP was obtained by condensing CP with SiO2-COOH using EDCI as a condensing agent. SiO2-COOH (13.44 mg, particle size 500 nm), CP (0.81 mg, 2 μmol), EDCI (45.86 mg, 40 μmol), HOBt (32.42 mg), DMAP (14.65 mg) and organic solvent (1 mL) were added to a reaction flask and stirred at 250 rpm for condensation reaction. After 24 h of reaction, the solvent was removed by centrifugation, and the sample was washed with MeOH:DCM (1:1) until the liquid was colorless. Then, it was washed three times with dd H2O and the sample was freeze-dried.

[0048] Infrared tests were performed on the raw materials SiO2-COOH, SiO2@EDU@CP, and the prepared dual-function algaecide SiO2@EDU@CP. Figure 1 The infrared spectra of CP, SiO2-COOH, and SiO2@EDU@CP in this embodiment are shown in Figure 1. Figure 1 It can be seen that the infrared spectrum of the synthesized SiO2@EDU@CP also contains characteristic peaks of acyl groups, indicating that the SiO2@EDU@CP algaecide is successfully synthesized by the method of the present invention.

[0049] The SiO2@EDU@CP photocatalytic reaction prepared in this example was observed under an inverted fluorescence microscope. Figure 2 This is an inverted fluorescence microscope image of SiO2@EDU@CP in this example. It can be seen that the SiO2@EDU@CP catalyst synthesized in this example can be observed to emit red fluorescence under an inverted fluorescence microscope ( Figure 2 is black and white, and the red fluorescence is Figure 2 The white part shows that CP has red fluorescence, while SiO2-COOH has no fluorescence.

[0050] [Example 2] Preparation of dual-function algaecide

[0051] 13.44 mg of SiO2-COOH (15 nm, 20 nm, 30 nm, 50 nm, and 500 nm) was added to a reaction flask. CP (0.81 mg), HOBt (32.42 mg), DMAP (14.65 mg), and EDCI (45.86 mg) were mixed with tetrahydrofuran and added to the reaction flask for condensation. The solvent was removed by centrifugation, and the mixture was washed with MeOH:DCM (1:1) until the liquid was colorless. The mixture was then rinsed three times with ddH2O and freeze-dried to obtain five SiO2@EDU@CP products.

[0052] [Example 3] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0053] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; five 4 mg / mL SiO2@EDU@CP solutions from Example 2 were added, and the pH was adjusted to 7 with NaOH or HCl. Three replicates were set up for each of the experimental and control wells. The first stage was the flocculation stage. The reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and then allowed to stand for 60 minutes before being photographed. Cells were counted from a sample 1 cm away and compared with cells in the control group to determine the survival rate. The survival rate was calculated using the following formula:

[0054]

[0055] Where C and T are the algal cell densities of the control group and CP treatment, respectively.

[0056] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0057] Method for extracting chlorophyll-a: Take the reaction solution at different time periods, centrifuge the algal cells, add 10 mL of 90% acetone, place in the dark at 4°C for 24 hours, then centrifuge at 4°C for 10 minutes, and collect the supernatant. Measure the absorbance of the supernatant using a visible spectrophotometer. The wavelengths are set to 663, 645, and 750 nm, and the total chlorophyll-a concentration is calculated according to the following formula (2):

[0058] Total chlorophyll-concentration (mg·L -1 )=11.64×(OD 663 -OD 750 )-2.16×(OD 645 -OD 750 )+0.10×(OD 630 -OD 750 ) Formula (2)

[0059] The results showed that after 740 minutes, the cell survival rates of 15nm, 20nm, 30nm, 50nm and 500nm SiO2@EDU@CP on Microcystis aeruginosa were 29%, 29%, 16%, 16% and 8%, respectively.

[0060] [Example 4] Inhibitory effect of SiO2@EDU@CP on Anabaena (FACHB-82)

[0061] The cell density of algae was 1.6×107 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and three replicates were set up for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0062] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0063] Method for extracting chlorophyll-a: Reaction solutions at different time periods were centrifuged with algal cells, and 10 mL of 90% acetone was added. The mixture was incubated in the dark at 4°C for 24 hours, followed by centrifugation at 4°C for 10 minutes. The supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0064] The results showed that after 740 min, the cell survival rate of 4 mg / mL SiO2@EDU@CP was 23% for the inhibition effect of Anabaena.

[0065] [Example 5] Inhibitory effect of SiO2@EDU@CP on Aphanizomenon flos-aquae (FACHB-1040)

[0066] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and three replicates were set up for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0067] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0068] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0069] The results showed that after 740 min, the cell survival rate of 4 mg / mL SiO2@EDU@CP inhibited the effect of Aphanizomenon blooms on 25%.

[0070] [Example 6] Inhibitory effect of SiO2@EDU@CP on Oscillatoria algae (FACHB-528)

[0071] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and three replicates were set up for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0072] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0073] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0074] The results showed that after 740 min, the cell survival rate of 4 mg / mL SiO2@EDU@CP was 17% for the inhibition effect of Oscillatoria spp.

[0075] [Example 7] Inhibitory effect of SiO2@EDU@CP on FACHB-920

[0076] The cell density of algae was 1.6×10 78 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and three replicates were set up for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0077] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0078] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0079] The results showed that after 740 min, the cell survival rate of 4 mg / mL SiO2@EDU@CP on FACHB-920 was 19%.

[0080] [Example 8] Inhibitory effect of 1 mg / mL SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0081] The cell density of algae was 1.6×10 7 8 mL of a cell suspension (100 μg / mL) was added to a reaction flask; 1 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and three replicates were set up for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before photographing. Cells were counted at a distance of 1 cm from the sample and compared with cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0082] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0083] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0084] The results showed that after 740 minutes, the cell survival rate of 1 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 51%. [Example 9] Inhibitory effect of 2 mg / mL SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0085] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 2 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and three replicates were set up for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before photographing. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0086] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0087] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0088] The results showed that after 740 minutes, the cell survival rate of 2mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 25%. [Example 10] Inhibitory effect of 3mg / mL SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0089] The cell density of algae was 1.6×10 78 mL of a cell suspension (100 μg / mL) was added to a reaction flask; 3 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and three replicates were set up for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before photographing. Cells were counted at a distance of 1 cm from the sample and compared with cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0090] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0091] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0092] The results showed that after 740 minutes, the cell survival rate of 3 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 17%. [Example 11] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0093] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 3 with NaOH or HCl. Three replicates were set for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0094] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0095] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0096] The results showed that after 740 minutes, the cell survival rate of 4 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 12%. [Example 12] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0097] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 4 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0098] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0099] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0100] The results showed that after 740 minutes, the cell survival rate of 4 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 17%. [Example 13] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0101] The cell density of algae was 1.6×10 78 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 5 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0102] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0103] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0104] The results showed that after 740 minutes, the cell survival rate of 4 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 17%. [Example 14] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0105] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 6 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate calculation formula is as shown in Formula (1) in Example 3:

[0106] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0107] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0108] The results showed that after 740 minutes, the cell survival rate of 4 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 17%. [Example 15] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0109] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0110] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0111] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0112] The results showed that after 740 minutes, the cell survival rate of 4 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 8%. [Example 16] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0113] The cell density of algae was 1.6×10 78 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 9 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0114] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0115] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0116] The results showed that after 740 minutes, the cell survival rate of 4 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 13%. [Example 17] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0117] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 10 with NaOH or HCl. Three replicates were set for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0118] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0119] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0120] The results showed that after 740 minutes, the cell survival rate of 4 mg / mL SiO2@EDU@CP on Microcystis aeruginosa was 16%. [Example 18] Preparation of dual-function algaecide

[0121] EDCI (0, 2.3, 4.6, 9.2, 18.4, 38.4, and 45.86 mg) was weighed, mixed with 13.44 mg of SiO2-COOH (13.44 mg), CP (0.81 mg), HOBt (32.42 mg), and DMAP (14.65 mg), and added to a reaction flask for condensation. The solvent was removed by centrifugation, and the mixture was washed with MeOH:DCM (1:1) until the liquid was colorless. The mixture was then rinsed three times with ddH2O and freeze-dried to obtain seven SiO2@EDU@CP compounds.

[0122] [Example 19] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0123] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 7 different 4 mg / mL SiO2@EDU@CPs obtained in Example 1 were added, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set for each of the experimental and control wells. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0124] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0125] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0126] The results showed that after 740 min, the cell survival rates of SiO2@EDU@CP with 0, 2.3, 4.6, 9.2, 18.4, 38.4 and 45.86 mg of EDCI on Microcystis aeruginosa were 80%, 8%, 9%, 8%, 8%, 9% and 8%, respectively.

[0127] [Example 20] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0128] The cell density of algae was 0.2×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0129] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0130] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0131] The results showed that after 740 min, the cell survival rate of SiO2@EDU@CP on Microcystis aeruginosa was 1.2%.

[0132] [Example 21] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0133] The algal cell density was 0.4×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0134] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0135] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0136] The results showed that after 740 min, the cell survival rate of SiO2@EDU@CP on Microcystis aeruginosa was 1.7%.

[0137] [Example 22] Inhibitory effect of SiO2@EDU@CP on Microcystis aeruginosa (FACHB-905)

[0138] The algal cell density was 0.8×10 7 8 mL of a cell suspension of 100 cells / mL was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added to the experimental group, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set up for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate was calculated using the formula (1) in Example 3:

[0139] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0140] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0141] The results showed that after 740 min, the cell survival rate of SiO2@EDU@CP on Microcystis aeruginosa was 6.9%.

[0142] [Example 23] Reaction bottle of SiO2@EDU@CP to inhibit Microcystis aeruginosa

[0143] The cell density of algae was 1.6×10 7 8 mL of a cell suspension (100 cells / mL) was added to a reaction flask. 4 mg / mL of SiO2@EDU@CP (from Example 1) was added, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set up for each experimental and control well. In the first stage, the flocculation process, the reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and then allowed to stand for 60 minutes before being photographed. In the second stage, the photoinhibition process, the reaction flask was left at room temperature under 23W white light. The reaction was photographed after 200, 380, 560, and 740 minutes, followed by 60 minutes of standing.

[0144] The results showed that (such as Figure 7 As shown in the figure), under the condition of 23W white light, SiO2@EDU@CP has an inhibitory effect on Microcystis aeruginosa.

[0145] [Comparative Example 1] Using CP alone to inhibit Microcystis aeruginosa

[0146] Referring to Example 15, 4 mg / mL SiO2@EDU@CP (wherein the amount of CP is 17 μM) was replaced with 17 μM CP, wherein the following remained unchanged:

[0147] The cell density of algae was 1.6×10 78 mL of a cell suspension of 100 μM cells / mL was added to a reaction flask; 17 μM CP was added to the experimental group, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set for the experimental group and the control wells. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate calculation formula is as shown in formula (1) in Example 3:

[0148] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0149] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0150] The results showed that after 740 minutes, the cell survival rate of Microcystis aeruginosa was 43% with the same dosage of CP.

[0151] [Comparative Example 2]

[0152] SiO2-COOH (13.44 mg, 500 nm particle size), EDCI (45.86 mg), HOBt (32.42 mg), DMAP (14.65 mg), and an organic solvent (1 mL) were added to a reaction flask for condensation. The solvent was removed by centrifugation, and the product was washed with MeOH:DCM (1:1) until the liquid became colorless. The product was then rinsed three times with ddH2O and freeze-dried to obtain SiO2@EDU.

[0153] The cell density of algae was 1.6×10 7 8 mL of a cell suspension of 100 μg / mL was added to a reaction flask; 4 mg / LSiO2@EDU was first added to the experimental group, followed by 17 μM CP, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set for the experimental group and the control wells, respectively. The reaction solution was stirred at 200 rpm for 2 minutes, at 60 rpm for 18 minutes, and allowed to stand for 60 minutes before taking a picture. The cells of the sample at 1 cm were counted and compared with the cells in the control group to determine the survival rate. The survival rate calculation formula is as shown in formula (1) in Example 3:

[0154] The second stage, photoinhibition, was conducted at room temperature under 23W white light. Cells were counted at 200, 380, 560, and 740 minutes. The photosensitivity inhibition rate of the SiO2@EDU@CP was measured using chlorophyll-a content.

[0155] Method for extracting chlorophyll-a: Reaction solutions were collected at different time periods, and algal cells were centrifuged and added with 10 mL of 90% acetone. The cells were incubated in the dark at 4°C for 24 hours, then centrifuged at 4°C for 10 minutes, and the supernatant was collected. The absorbance of the supernatant was measured using a visible spectrophotometer at wavelengths set to 663, 645, and 750 nm. The total chlorophyll-a concentration was calculated using the following survival rate formula, as described in Formula (2) in Example 3.

[0156] The results showed that after 740 minutes, the cell survival rate of Microcystis aeruginosa was 35% with the same dosage of CP.

[0157] [Example 24] Oil immersion image of SiO2@EDU@CP inhibiting Microcystis aeruginosa

[0158] The cell density of algae was 1.6×10 7 8 mL of a cell suspension (100 cells / mL) was added to a reaction flask; 4 mg / mL of SiO2@EDU@CP obtained in Example 1 was added, and the pH was adjusted to 8 with NaOH or HCl. Three replicates were set up for each experimental group and control well. In the first stage, the flocculation process, the reaction solution was stirred at 200 rpm for 2 minutes, then at 60 rpm for 18 minutes, and allowed to stand for 60 minutes. The reaction solution was sampled from a depth of 1 cm and observed under a fluorescence microscope. In the second stage, the photoinhibition process, the reaction flask was placed at room temperature under a 23W white light lamp. The reaction solution was sampled at 200, 380, 560, and 740 minutes, allowed to stand for 60 minutes, and then observed under a fluorescence microscope.

[0159] The results showed that (such as Figure 8 As shown in the figure), under the condition of 23W white light, SiO2@EDU@CP has an inhibitory effect on Microcystis aeruginosa.

[0160] [Example 25] TEM test of SiO2@EDU@CP inhibition of Microcystis aeruginosa

[0161] The cell density of algae was 1.6×10 7Add 8 mL of a cell suspension containing 100 cells / mL to a reaction flask; add 4 mg / mL of SiO2@EDU@CP obtained in Example 1, adjust the pH to 8 with NaOH or HCl, and set up three replicates for the experimental group and control wells. Collect cells at 0 h, 20 min, 200 min, and 740 min, centrifuge at 6000 × g for 10 minutes, wash three times with PBS, discard the supernatant, and perform the following operations after obtaining the bacteria: place them in a 1.5 mL centrifuge tube, add 2.5% glutaraldehyde solution (fill the centrifuge tube with fixative so that the sample is completely immersed in the fixative), and store at 4°C. Do not discard the fixative. Generally, fix for 12 hours. Discard the fixative and rinse the sample three times with 0.1M, pH 7.0 phosphate buffer (15 min each). Fix the sample with 1% osmium sulfate solution for 1-2 hours. Carefully remove the waste osmium sulfate solution and rinse the sample three times with 0.1M, pH 7.0 phosphate buffer (15 min each). Dehydrate the sample with a gradient of ethanol (30%, 50%, 70%, 80%, 90%, and 95%) for 15 minutes each, then with 100% ethanol for 20 minutes. Finally, transition to pure acetone for 20 minutes. Treat the sample with a mixture of embedding medium and acetone (V / V = 1 / 1) for 1 hour, a mixture of embedding medium and acetone (V / V = 3 / 1) for 3 hours, and pure embedding medium overnight. Embed the infiltrated sample and heat at 70°C overnight to obtain the embedded sample. The samples were sliced ​​in a LEICA EMUC7 ultramicrotome to obtain 70-90 nm slices, which were then stained with a lead citrate solution and a 50% ethanol saturated solution of uranyl acetate for 5-10 min each. After drying, the slices were observed in a transmission electron microscope.

[0162] The results are as follows Figure 9 As shown, under 23W white light conditions, SiO2@EDU@CP acted on cells. The cell membrane and cell wall of the control group were intact, the cytoplasm was uniform, and the thylakoids were clearly visible. As time went by, the cell membrane and cell wall of the experimental group became incomplete, the cytoplasm was uneven and leaky, and the thylakoids were unclear.

[0163] Under 23W white light conditions, SiO2@EDU@CP affects the cell morphology during the inhibition of Microcystis aeruginosa.

[0164] [Example 26]

[0165] On July 29, 2021, we collected fresh harmful algae near the Taihu Xingang Bridge Salvage Station (31°'41'07S / 120°24'19'W) and divided them into three groups: control group, 2.8 mg / mL SiO2@EDU@CP and 4 mg / mL SiO2@EDU@CP obtained in Example 1, under light intensity of 14-25 mW / cm2 Under the sunlight condition, the reaction time is 7.5h. Figure 10 As shown, the Taihu algae in the 2.8 mg / mL SiO2@EDU@CP and 4 mg / mL SiO2@EDU@CP groups changed from green to white over time.

[0166] In summary, under sunlight irradiation, 2.8 mg / mL SiO2@EDU@CP and 4 mg / mL SiO2@EDU@CP had inhibitory effects on Taihu algae.

[0167] [Example 27]

[0168] On September 5, 2022, we collected fresh algae from the Suwo Bridge in Taihu Lake, China (31°30'4"N, 120°7'41") for further experiments. The experiment was divided into three groups: a control group, a 2.8mg / mL SiO2@EDU@CP group, and a 4mg / mL SiO2@EDU@CP group obtained in Example 1. The reaction system was 1L. Under a light intensity of 14-25mW / cm 2 Under sunlight conditions, the reaction time was 7.5 hours. Samples were collected at 0 hours, 1.5 hours, 3 hours, 4.5 hours, 6 hours, and 7.5 hours. The algae were separated by filtration. After obtaining the cells, the following operations were performed: 90% acetone was added overnight, and the cells were placed in a 4°C refrigerator in the dark. The extract was centrifuged at 10,000 rpm for 10 minutes at 4°C in a high-speed refrigerated centrifuge (Hitachi, Japan), and the supernatant was collected. The chlorophyll-a content was calculated using the following formula (2) in Example 3.

[0169] The results are as follows Figure 11 As shown, the chlorophyll a contents in the control group and the experimental group were 12.5 mg / mL, 0.7 mg / mL, and 0.6 mg / mL at 7.5 h, respectively.

[0170] In summary, 2.8 mg / mL SiO2@EDU@CP and 4 mg / mL SiO2@EDU@CP had good inhibitory effects on Taihu algae under sunlight irradiation.

[0171] [Example 28] CP content in the reaction solution of sunlight experiment

[0172] For actual cyanobacteria reactions, samples were collected at 0, 1.5, 3, 4.5, 6, and 7.5 hours. The algae were separated by filtration, and the resulting liquid was extracted with an equal volume of dichloromethane. The organic phase was rotary evaporated and reconstituted with methanol for HPLC. The amount of CP leakage was measured using a Waters instrument.

[0173] Table 1 Liquid chromatograph operating parameters

[0174]

[0175] like Figure 11 The amount of CP leakage in the reaction system was detected. After 7.5 hours of reaction, no CP was detected in the 2.8 mg / mL SiO2@EDU@CP and 4 mg / mL SiO2@EDU@CP reaction solutions obtained in Example 1, indicating that SiO2@EDU@CP has no potential for secondary pollution in actual harmful algae treatment.

[0176] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A method for preparing a dual-functional algaecide SiO2@EDU@CP, characterized in that: SiO2-COOH, EDCI, and cercosporin were condensed in the presence of HOBt and DMAP to obtain the bifunctional algaecide SiO2@EDU@CP. The mass ratio of cercosporin to SiO2-COOH is 1:(15-20); the molar ratio of cercosporin to EDCI is 1:(1-20); The dual-functional algaecide SiO2@EDU@CP causes flocculation of different harmful algae and improves the efficiency of electron transfer and separation of electron-hole pairs, thereby improving the efficiency of photocatalytic inhibition of harmful algae. The preparation process of the SiO2-COOH includes: first, performing SiO2 amination, adding 1 g SiO2, 49 mL toluene, 1 mL APTES and 0.15 mL triethylamine to a reaction bottle for oil bath reaction at 110°C for 5 hours. After the reaction, the sample is cooled to room temperature, centrifuged to remove toluene, washed with acetone 5 times, and vacuum dried to obtain SiO2-NH2; adding 3 g SiO2-NH2 to 100 mL ethanol, continuously adding 7.5 g glutaric anhydride, stirring at 37°C for 3 hours until the reaction is completed, centrifuging to remove ethanol, washing with 0.1 M NaCl solution 5 times to remove unreacted glutaric anhydride, and freeze-drying the solid obtained by centrifugation to obtain SiO2-COOH.

2. The method according to claim 1, wherein The particle size of SiO2-COOH is 500 nm.

3. The method according to claim 1, characterized in that The mass ratio of cercosporin to HOBt is 1:(30-50); the mass ratio of cercosporin to DMAP is 1:(15-20).

4. The method according to claim 1, wherein The condensation reaction is carried out in an organic solvent; the organic solvent is tetrahydrofuran, dichloromethane, dimethylformamide, ethyl acetate or acetonitrile; and the concentration of SiO2-COOH relative to the organic solvent is 10-20 mg / mL.

5. The dual-functional algaecide SiO2@EDU@CP prepared by the method according to any one of claims 1 to 4.

6. Use of the dual-functional algaecide SiO2@EDU@CP according to claim 5 in inhibiting the growth of harmful algae.

7. The use according to claim 6, characterized in that The application process includes: adding the dual-functional algaecide SiO2@EDU@CP to a water body containing harmful algae, stirring, allowing to stand, and then placing it under visible light for treatment.

8. The use according to claim 7, characterized in that The visible light is selected from the group consisting of: 5-23 W white light, 20 W purple LED, 20 W blue LED, 20 W green LED, and sunlight; the amount of SiO2@EDU@CP added is 1-4 mg / mL; and the harmful algae include any one or more of the following: Microcystis aeruginosa, Anabaena, Aphanizomenon aquatica, Oscillatoria, Phytoschizophyllum, and Taihu cyanobacteria.

Images