Method for degrading microcystis aeruginosa and algal toxin thereof by using membrane electrode

Abstract

The invention discloses a method for degrading microcystis aeruginosa and algal toxins thereof by using a membrane electrode, belongs to the technical field of algal cell and algal toxin treatment, and provides a method for degrading microcystis aeruginosa and algal toxins thereof by using a membrane electrode, which comprises the following steps: preparing a membrane casting solution, coating a RuO2-Ti electrode and / or a SnO2-Ti electrode with the membrane casting solution, and preparing the membrane electrode. Soaking in deionized water for phase inversion to form a membrane electrode; mixing the polluted solution with NaCl, and adjusting the pH value to obtain a polluted solution to be treated; a membrane electrode is used as an anode, a titanium mesh is used as a cathode, an electro-catalysis filtration system is constructed, a pollution solution to be treated sequentially flows through the cathode and the anode, electro-catalysis reaction is performed, and microcystis aeruginosa and / or microcystis aeruginosa toxins are / is degraded. The microcystis aeruginosa and algal toxin produced by the microcystis aeruginosa can be efficiently degraded, and the removal effect of pollutants is remarkably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of algal cell and algal toxin treatment, and in particular relates to a method for degrading Microcystis aeruginosa and its algal toxins by using a membrane electrode. Background Art

[0002] Toxic microalgae are widely distributed in various aquatic environments and can produce toxic secondary metabolites. They can thrive under a variety of environmental conditions and show strong fecundity and competitiveness. In recent years, large-scale ecological disturbances related to urbanization, increased agricultural activities and the introduction of invasive species, combined with climate change, have led to an increase in the intensity, frequency and geographical distribution of toxic microalgae. For example, in the past, cyanobacterial blooms only affected a few areas, but now their impact has expanded to lakes, rivers, wetlands, estuaries and near-shore marine waters everywhere. Microcystins are a class of cyclic peptide toxins produced by cyanobacteria (such as Microcystis aeruginosa) that have attracted much attention due to their strong toxicity and multiple hazards to humans, animals and ecosystems. Humans may ingest microcystins by drinking contaminated water or eating contaminated food, leading to acute or chronic poisoning. Acute exposure usually manifests as nausea, vomiting, diarrhea and liver damage, while long-term exposure may lead to more serious health problems such as cirrhosis and liver cancer, and microcystins have been listed as potential carcinogens. The toxicity, persistence and widespread distribution of microcystins in the environment make them a serious class of environmental pollutants, posing a major challenge to public health and water resource management.

[0003] Traditional membrane separation relies solely on the physical selectivity of the membrane (such as pore size, hydrophilicity / hydrophobicity, chemical selectivity, etc.) to filter particles, microorganisms or molecules. Organic pollutants cannot be effectively degraded or converted by relying solely on physical filtration. Traditional membrane separation technology may be powerless for tiny molecules or soluble pollutants, and is easily affected by membrane fouling, requiring frequent cleaning and replacement of membrane materials. Traditional electrocatalytic systems usually use electrodes that do not have separation functions. The focus is on the catalytic performance and reaction rate of the electrode material. It does not involve the separation process and is usually only used to degrade specific pollutants. After treatment, additional separation steps (such as precipitation and filtration) are required to remove the products or unreacted products.

[0004] Electrocatalytic filtration combines the dual effects of electrochemical oxidation and membrane filtration. Not only can particles and microorganisms be removed by physical separation, but organic pollutants and harmful compounds such as algae toxins can also be degraded by electrocatalytic reactions. This process can simultaneously achieve the interception and conversion of pollutants. Electrocatalysis can reduce the deposition of organic matter on the membrane surface, thereby alleviating the problem of membrane fouling and extending the service life of the membrane. This electrode with membrane separation function not only participates in the electrochemical reaction, but also has a separation function. Electrocatalytic filtration technology usually operates at a lower voltage and has relatively low energy consumption, which can save energy while achieving efficient pollutant removal. The porous electrode material used in the electrocatalytic filtration system has self-cleaning ability, which reduces the pollution and passivation problems on the electrode surface and extends the service life and maintenance cycle of the electrode. Through the synergistic effect of electrochemistry and membrane filtration, electrocatalytic membrane filtration can achieve multiple treatment effects in a single process, improving the efficiency and effectiveness of sewage treatment.

[0005] Electrocatalytic filtration technology can efficiently remove algae and their algae toxins. The key lies in the indirect oxidation effect during the electrocatalytic process - the strong oxidizing active groups generated in the reaction system can inactivate algae and degrade their related organic matter. Specifically, the algae cells are intercepted by the interception effect of the membrane, and the algae cells are destroyed under the action of the electric field to release algae toxins, which are then degraded under the conditions of electrocatalytic reaction. The reaction conditions of electrocatalytic filtration (such as voltage, current density, pH value, etc.) need to be carefully controlled to achieve the optimal degradation effect. Although electrocatalytic membrane filtration has performed well in degrading toxic microalgae (such as Microcystis aeruginosa), the degradation effect and degradation mechanism of microcystin toxins still need further study. Summary of the invention

[0006] In order to solve the above technical problems, the present invention proposes a method for degrading Microcystis aeruginosa and its algal toxins by using a membrane electrode, so as to efficiently degrade Microcystis aeruginosa and its algal toxins.

[0007] To achieve the above object, the present invention provides a method for degrading Microcystis aeruginosa and its algal toxins using a membrane electrode, comprising the following steps: (1) preparing a casting solution, coating the casting solution on a RuO2-Ti electrode and / or a SnO2-Ti electrode, and immersing the electrode in deionized water for phase conversion to form a membrane electrode; (2) The contaminated solution is mixed with NaCl and the pH is adjusted to obtain the contaminated solution to be treated; (3) Using the membrane electrode obtained in step (1) as an anode and the titanium mesh as a cathode, an electrocatalytic filtration system is constructed, and the contaminated solution to be treated obtained in step (2) flows through the cathode and the anode in sequence, undergoing an electrocatalytic reaction to degrade Microcystis aeruginosa and / or Microcystis aeruginosa toxins.

[0008] Preferably, the casting solution in step (1) is prepared by dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methylpyrrolidone to obtain the casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methylpyrrolidone is 8g:3g:89mL.

[0009] Preferably, the soaking time in step (1) is 24 to 26 hours.

[0010] Preferably, the contaminated solution in step (2) is a solution of Microcystis aeruginosa or a solution of Microcystis aeruginosa toxin, and the algae density of the solution of Microcystis aeruginosa is 10 4 ~10 6 cells / mL, the concentration of the M. aeruginosa toxin solution is 5-100 μg / L; the mixing ratio of the contaminated solution and NaCl in step (2) is 1L:10-30g.

[0011] Further preferably, the microcystin in the microcystin solution is microcystin-LR, whose chemical formula is C 49 H 74 N 10 O 12 .

[0012] Preferably, in step (2), the pH is adjusted to 6.9-7.1.

[0013] Preferably, the flow rate of the contaminated solution to be treated in step (3) is 10 mL / min.

[0014] Preferably, the current density of the electrocatalytic reaction in step (3) is 5-20 mA / cm 2 The electrocatalytic reaction time is 120 to 240 minutes.

[0015] Preferably, in step (3), the distance between the anode and the cathode is 1 cm.

[0016] Preferably, after the degradation of Microcystis aeruginosa and / or Microcystis aeruginosa toxins in step (3), the process further comprises extracting the permeate from the anode side.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: The present invention discloses a composite membrane electrode made of an organic membrane and a metal porous electrode to construct an electrocatalytic filtration system, thereby effectively degrading Microcystis aeruginosa and its algae toxins in water. When voltage is applied to the membrane electrode, active oxygen species such as hydroxyl radicals (·OH), superoxide (O -) and hydrogen peroxide (H2O2). These reactive oxygen species can damage the cell membrane of Microcystis aeruginosa, causing cell death or loss of activity. The cell membrane structure of the algae is destroyed during the electrochemical process, thereby inactivating Microcystis aeruginosa. When the cell membrane of Microcystis aeruginosa is destroyed, the cell contents, including microcystins, are released into the water. Due to the action of the membrane electrode, the algae cells can be quickly destroyed, leading to the release of toxins. Microcystins released into the water, such as microcystin-LR, can be further degraded by adsorption, interception, and electrocatalytic processes on the membrane electrode. For example, reactive oxygen species (especially hydroxyl radicals) can oxidatively decompose algae toxins, break their internal covalent bonds, and decompose them into non-toxic small molecule compounds, such as carbon dioxide and water, to achieve effective treatment of algae toxins.

[0018] (1) The electrocatalytic membrane filtration system designed in the present invention can efficiently degrade Microcystis aeruginosa and the algal toxins it produces. Through the dual effects of electrocatalysis and membrane filtration, the removal effect of pollutants is significantly improved.

[0019] (2) Compared with other technologies, the present invention can not only degrade toxic organic matter through electrocatalytic reaction, but also remove pollutants through membrane filtration, thereby improving the efficiency and effect of sewage treatment.

[0020] (3) The present invention operates at a relatively low voltage and has relatively low energy consumption; the self-cleaning ability of the porous electrode material reduces the contamination and passivation problems on the electrode surface, thereby extending the service life and maintenance cycle of the electrode.

[0021] (4) The present invention is not only applicable to the degradation of Microcystis aeruginosa, but also to the treatment of other toxic microalgae and their related pollutants, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a structural schematic diagram of the electrocatalytic filtration system of the present invention; Figure 2 The inactivation effect of RuO2-Ti electrode on Microcystis aeruginosa at different current densities; Figure 3 The effect of SnO2-Ti electrode inactivating Microcystis aeruginosa at different current densities; Figure 4Schematic diagram of the membrane electrode structure of the present invention, in which 1 represents an organic membrane, 2 represents a non-woven fabric, 3 represents a RuO2-Ti electrode, and 4 represents an organic membrane; Figure 5 For RuO2-Ti film electrode and SnO2-Ti film electrode at 15mA / cm 2 The effect of current density on inactivation of Microcystis aeruginosa; Figure 6 The degradation effect diagram of different concentrations of microcystin aeruginosa toxin is shown in Figure a, 5 μg / L microcystin aeruginosa toxin, b, 30 μg / L microcystin aeruginosa toxin, and c, 100 μg / L microcystin aeruginosa toxin; Figure 7 This is a diagram showing the degradation effect of ruthenium-titanium film electrode on Microcystis aeruginosa and Dunaliella. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] Sources of materials used in the present invention: Microcystis aeruginosa was purchased from the freshwater algae species bank of the Institute of Hydrobiology, Chinese Academy of Sciences, with the serial number FACHB-905.

[0030] Example 1 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) Using membrane electrode as anode and titanium mesh as cathode, with the distance between anode and cathode being 1 cm, an electrocatalytic filtration system was constructed (e.g. Figure 1 As shown in the figure, the contaminated solution to be treated flows through the titanium mesh at a flow rate of 10 mL / min, undergoes cathode rejection, and then reaches the anode conductive film. The current density is controlled at 15 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0031] like Figure 2 As shown, the current density is controlled to be 15 mA / cm 2 The algaecide rate is 3.00.

[0032] Example 2 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 5 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0033] like Figure 2 As shown, the current density is controlled to be 5 mA / cm 2 The algaecide rate was 1.74.

[0034] Example 3 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 10 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0035] like Figure 2 As shown, the current density is controlled to be 10 mA / cm 2 The algaecide rate is 2.05.

[0036] Example 4 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 20 mA / cm2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0037] like Figure 2 As shown, the current density is controlled to be 20 mA / cm 2 The algaecide rate is 2.70.

[0038] Example 5 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a SnO2-Ti electrode, immersing the electrode in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 15 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The membrane then pumps the permeate out from the anode side via a peristaltic pump.

[0039] like Figure 3 As shown, the current density is controlled to be 15 mA / cm 2 The algaecide rate was 2.52.

[0040] Example 6 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a SnO2-Ti electrode, immersing the electrode in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 5 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0041] like Figure 3 As shown, the current density is controlled to be 5 mA / cm 2 The algaecide rate was 1.72.

[0042] Example 7 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a SnO2-Ti electrode, immersing the electrode in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 10 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0043] like Figure 3 As shown, the current density is controlled to be 10 mA / cm 2 The algaecide rate was 1.96.

[0044] Example 8 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a SnO2-Ti electrode, immersing the electrode in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 43 L of a solution of Microcystis aeruginosa (with deionized water as solvent) with a concentration of 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 20 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0045] like Figure 3 As shown, the current density is controlled to be 20 mA / cm 2 The algaecide rate was 2.22.

[0046] Example 9 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) 3 L of a 5 μg / L solution of Microcystis aeruginosa toxin (deionized water as solvent) was mixed with 46.8 g of NaCl and the pH was adjusted to 7 to obtain the contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 15 mA / cm 2 , electrocatalytic reaction for 120min, degradation of Microcystis aeruginosa toxin; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0047] like Figure 6 As shown, the membrane electrode can completely degrade Microcystin-LR within 5 minutes, and the degradation efficiency reaches 100%.

[0048] Example 10 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) 3 L of a 30 μg / L solution of Microcystis aeruginosa toxin (deionized water as solvent) was mixed with 46.8 g of NaCl and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 15 mA / cm 2 , electrocatalytic reaction for 120min, degradation of Microcystis aeruginosa toxin; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0049] like Figure 6 As shown, the membrane electrode can completely degrade Microcystin-LR within 5 minutes, and the degradation efficiency reaches 100%.

[0050] Embodiment 11 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) 3 L of a 100 μg / L solution of Microcystis aeruginosa toxin (deionized water as solvent) was mixed with 46.8 g of NaCl and the pH was adjusted to 7 to obtain the contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 15 mA / cm 2 , electrocatalytic reaction for 120min, degradation of Microcystis aeruginosa toxin; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0051] like Figure 6 Middle a, Figure 6 Medium b and Figure 6 As shown in c, the membrane electrode can completely degrade Microcystin-LR within 5 minutes, with a degradation efficiency of 100%.

[0052] according to Figure 5As shown in the figure, both RuO2-Ti membrane electrode and SnO2-Ti membrane electrode have better degradation effect on Microcystis aeruginosa. The degradation efficiency of RuO2-Ti membrane electrode is faster than that of SnO2-Ti membrane electrode, and the algae killing rate can reach 100%.

[0053] Comparative Example 1 (1) preparing a casting solution, dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methyl pyrrolidone to obtain a casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methyl pyrrolidone is 8 g:3 g:89 mL; coating the casting solution on a RuO2-Ti electrode, soaking it in deionized water for 25 h for phase inversion, and forming a membrane electrode; (2) Algae density is 10 4 3 L of Dunaliella solution (deionized water as solvent) with 10 cells / mL was mixed with 46.8 g of NaCl, and the pH was adjusted to 7 to obtain a contaminated solution to be treated; (3) The membrane electrode was used as the anode and the titanium mesh was used as the cathode. The distance between the anode and the cathode was 1 cm. An electrocatalytic filtration system was constructed. The polluted solution to be treated flowed through the titanium mesh at a flow rate of 10 mL / min, experienced cathode rejection, and then reached the anode conductive membrane. The current density was controlled to be 20 mA / cm 2 , electrocatalytic reaction lasted 180min, degrading Microcystis aeruginosa; (4) The permeate is then pumped out from the anode side via a peristaltic pump.

[0054] like Figure 7 As shown, the ruthenium-titanium film electrode has the best degradation effect on Microcystis aeruginosa, but the degradation effect on Dunaliella is lower than that on Microcystis aeruginosa.

[0055] Experimental example The concentration of algal toxins released by algal cell rupture during electrocatalytic filtration was detected by enzyme-linked immunosorbent assay (ELISA). The sample treated in the example was added to an ELISA plate with microcystin antibodies to perform an antigen-antibody binding reaction. Figure 4 The schematic diagram of the membrane electrode structure of the present invention. After washing, the enzyme-labeled secondary antibody is added, and then the color substrate is added. After a certain reaction time, the reaction is terminated and the absorbance value is measured by an enzyme marker. The concentration of algae toxins in the sample is calculated according to the standard curve and compared with the initial concentration to analyze the removal effect of the electrocatalytic filtration process on algae toxins.

[0056] The results showed that in the initial stage of electrocatalytic filtration, the concentration of algal toxins increased rapidly as the cells of Microcystis aeruginosa ruptured. As the filtration time increased and the electrocatalytic effect continued, the concentration of algal toxins in the filtrate gradually decreased, and the degradation effect could reach 99%. This shows that the electrocatalytic filtration system can not only destroy algal cells and release toxins, but also further degrade the released algal toxins.

[0057] Liquid chromatography-mass spectrometry (LC-MS) was used to detect 100 μg / L microcystin after degradation for 5 minutes, 30 minutes, and 120 minutes in Example 11. By analyzing the structure of the intermediate products at different time points, a preliminary degradation pathway diagram of microcystin under electrocatalysis was drawn (e.g. Figure 6 as shown).

[0058] The degradation process mainly went through primary ring-opening reaction, oxidative fracture and final mineralization process. The study not only confirmed the high efficiency of electrocatalytic filtration system in the degradation of microcystin, but also revealed the various intermediates formed in the degradation process and their evolution process. This study provides important theoretical support for further optimizing the degradation technology of microcystin, and also provides a new perspective for understanding the molecular mechanism of electrocatalytic degradation.

[0059] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for degrading Microcystis aeruginosa and its algal toxins using a membrane electrode, characterized in that: The following steps are involved: (1) preparing a casting solution, coating the casting solution on a RuO2-Ti electrode and / or a SnO2-Ti electrode, and immersing the electrode in deionized water for phase conversion to form a membrane electrode; (2) The contaminated solution is mixed with NaCl and the pH is adjusted to obtain the contaminated solution to be treated; (3) Using the membrane electrode obtained in step (1) as an anode and the titanium mesh as a cathode, an electrocatalytic filtration system is constructed, and the contaminated solution to be treated obtained in step (2) flows through the cathode and the anode in sequence, undergoing an electrocatalytic reaction to degrade Microcystis aeruginosa and / or Microcystis aeruginosa toxins.

2. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: The step (1) of preparing the casting solution is as follows: dissolving polyvinylidene fluoride and polyvinyl pyrrolidone in N-methylpyrrolidone to obtain the casting solution, wherein the ratio of polyvinylidene fluoride, polyvinyl pyrrolidone and N-methylpyrrolidone is 8 g:3 g:89 mL.

3. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: The soaking time in step (1) is 24 to 26 hours.

4. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: The contaminated solution in step (2) is a solution of Microcystis aeruginosa or a solution of Microcystis aeruginosa toxin, and the algae density of the solution of Microcystis aeruginosa is 10 4 ~10 6 cells / mL, the concentration of the M. aeruginosa toxin solution is 5-100 μg / L; the mixing ratio of the contaminated solution and NaCl in step (2) is 1L:10-30g.

5. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 4, characterized in that: The microcystin in the microcystin solution is microcystin-LR, and its chemical formula is C 49 H 74 N 10 O 12 .

6. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that the pH is adjusted to 6.9-7.1 in step (2).

7. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: The flow rate of the contaminated solution to be treated in step (3) is 10 mL / min.

8. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: The current density of the electrocatalytic reaction in step (3) is 5-20 mA / cm 2 The electrocatalytic reaction time is 120 to 240 minutes.

9. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: In step (3), the distance between the anode and the cathode is 1 cm.

10. The method for degrading Microcystis aeruginosa and its algal toxins according to claim 1, characterized in that: After the degradation of Microcystis aeruginosa and / or Microcystis aeruginosa toxins in step (3), the permeate may be withdrawn from the anode side.

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