Landscape water algae control method based on plant-microorganism electrochemical system

Abstract

The invention relates to the technical field of landscape lake water body algae control, in particular to a landscape water body algae control method based on a plant-microorganism electrochemical system, which is composed of aquatic plants and a microorganism electrochemical system. The aquatic plants comprise submerged plants (potamogeton distinctus, myriophyllum spicatum, vallisneria natans and hornwort) and floating plants (nymphaea tetragona, nymphoides peltatum and eichhornia crassipes). The microbial electrochemical system main body is composed of an anode electrode and a cathode electrode, the anode electrode is made of a nickel-plated carbon felt material, the cathode electrode is made of a vanadium-based hybrid material, the anode electrode and the cathode electrode are connected through a stainless steel rod, and an anaerobic biological membrane is attached to the surface of the anode electrode. By coupling the plant and microorganism electrochemical system, the purpose of controlling the algae in the urban landscape water body is achieved, pollutants such as nitrogen, phosphorus and organic matters in the water body and sediments can be synchronously removed, and the method has the characteristics of simplicity in operation, low cost and excellent treatment effect.

Description

Technical Field

[0001] The present invention relates to the technical field of controlling algae in landscape lake water bodies, and particularly to a method for controlling algae in landscape water bodies based on a plant-microbial electrochemical system. Background Art

[0002] The discharge of a large amount of nitrogen and phosphorus-rich wastewater into lake water bodies can lead to eutrophication of the lakes and thus trigger algal blooms. The dominant toxin-producing algae among them is a type of Microcystis that produces microcystin. Therefore, how to control the algal bloom disasters caused by water body eutrophication is an important topic that has attracted much attention in the field of lake ecological environment governance worldwide.

[0003] In order to solve the problems existing in the algae removal technology, such as low removal efficiency, secondary pollution, long reaction time, low algae removal efficiency caused by low water body conductivity, and the inability to completely remove the nutrient elements in the water body resulting in a vicious cycle, and to make up for the deficiencies of the algae removal technology, it is particularly necessary to design a new system and method that can simultaneously remove algae and nitrogen and phosphorus.

[0004] In view of the above defects, the creator of the present invention finally obtained the present invention through long-term research and practice. Summary of the Invention

[0005] The purpose of the present invention is to solve the problems existing in the algae removal technology, such as low removal efficiency, secondary pollution, long reaction time, low algae removal efficiency caused by low water body conductivity, and the inability to completely remove the nutrient elements in the water body resulting in a vicious cycle, and to make up for the deficiencies of the algae removal technology, and to provide a method for controlling algae in landscape water bodies based on a plant-microbial electrochemical system.

[0006] In order to achieve the above purpose, the present invention discloses a method for controlling algae in landscape water bodies based on a plant-microbial electrochemical system, including the following steps:

[0007] S1, arranging an anode electrode in the bottom mud, and the arrangement depth is 10 - 15 cm;

[0008] S2, planting submerged plants at the position where the anode electrode is arranged;

[0009] S3, arranging a cathode electrode on the water surface, and connecting the anode and the cathode with a stainless steel rod;

[0010] S4, planting floating plants at the position where the cathode electrode is arranged.

[0011] In the step S1, the anode electrode is made of nickel-plated carbon felt material, and it is processed before use to make the pores evenly distributed on its surface so that the roots of the plants can pass through, and the pore diameter is 2 - 4 mm.

[0012] In the step S1, an anaerobic biofilm is attached to the anode surface. The preparation method of the anaerobic biofilm is as follows: The anaerobic sludge obtained by inoculating the anode electrode with the anaerobic sludge domesticated by the anaerobic reactor of the landscape water sediment suspension is the anaerobic biofilm.

[0013] The landscape water sediment suspension is prepared by mixing sediment and deionized water in a mass ratio of 1:1 to 1:5.

[0014] In the step S2, the submerged plants include Potamogeton distinctus, Myriophyllum verticillatum, Vallisneria natans, and Ceratophyllum demersum. The planting ratio of Potamogeton distinctus, Myriophyllum verticillatum, Vallisneria natans, and Ceratophyllum demersum is 1:1 - 3:1 - 2:2 - 3.

[0015] In the step S3, the cathode electrode is a vanadium-based hybrid cathode material. Before use, the cathode electrode is subjected to a multi-layer grid treatment to make pores (with a pore diameter of 2 - 4 mm) evenly distributed on its surface so that the roots of floating plants can pass through and twine around. The multi-layer treatment makes the combination between the cathode and the roots of floating plants closer.

[0016] The preparation method of the vanadium-based hybrid cathode material includes the following steps:

[0017] S31, Stir and mix Ti3AlC2 with hydrofluoric acid, react at 40 - 60 °C for 6 - 10 hours, and after the reaction is completed, rinse repeatedly with deionized water to remove the residual hydrofluoric acid;

[0018] S32, Add the material obtained in the step S31 and 1-propyl-3-methylimidazolium bromide to deionized water, and perform ultrasonic treatment and stir evenly;

[0019] S33, Add NH4VO3 to the mixture obtained in the step S32, stir for 6 - 8 h to obtain a composite material;

[0020] S34, Immerse the three-dimensional porous carbon nanosheet into the composite material obtained in the step S33, the treatment time is 30 - 60 s, after drying and washing, perform thermal reduction at 200 - 300 °C for 2 - 3 hours to obtain the vanadium-based hybrid cathode electrode.

[0021] In the step S31, the mass ratio of Ti3AlC2 to hydrofluoric acid is 1:2 - 1:5.

[0022] In the step S32, the dosage of the material obtained in the step S31 is 3 mg, the dosage of 1-propyl-3-methylimidazolium bromide is 150 mg, and the dosage of deionized water is 100 mL.

[0023] In the step S33, the dosage of NH4VO3 is 2 - 3 g.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. In the present invention, submerged plants are planted on the anode. The roots of the submerged plants can secrete a variety of organic substances, which not only provide easily utilizable carbon sources for microorganisms but also enhance the reaction activity of the anode electrode. Organic acids and other metabolites in the root exudates can promote the progress of the electrochemical reaction, improve the electron transfer efficiency, and thus enhance the current output of the anode. In addition, the submerged plants can also absorb and utilize nitrogen, phosphorus, and organic pollutants in the sediment, thereby reducing the pollutant emissions from the sediment;

[0026] 2. In the present invention, floating plants are planted on the cathode. The floating plants also have important ecological functions, and their root exudates can improve the electrochemical reaction of the cathode electrode. The microenvironment formed by the roots of the floating plants in the water can promote the growth and reproduction of microorganisms, increase the thickness of the biofilm on the cathode surface, and thus enhance the conductivity and reaction rate of the cathode to better remove algae in the water body and reduce organic pollutants in the upper layer of the water body. In addition, the floating plants themselves can also absorb and utilize nitrogen, phosphorus, and organic pollutants in the water body;

[0027] 3. The vanadium-based hybrid cathode material in the present invention has excellent electrochemical performance and stability. Its high conductivity and good electrochemical activity enable it to perform well in the cathode reaction and effectively promote the transfer of electrons. In addition, the corrosion resistance and thermal stability of the vanadium-based material enable it to have a longer service life in a complex water body environment, reducing the maintenance cost;

[0028] 4. The present invention uses the sediment of urban landscape water bodies to domesticate anaerobic sludge, which can enable the system to quickly adapt to the actual environment. The rich microbial community and organic matter in the sediment can accelerate the formation of anaerobic biofilms, improve the startup speed and stability of the system. This method not only improves the adaptability of the system but also effectively utilizes local resources, reduces external input, and enhances the ecological friendliness of the system;

[0029] 5. The plant-microbial electrochemical system in the present invention combines the advantages of plants and microorganisms, can effectively remove algae in the water body, and at the same time control the concentrations of pollutants such as nitrogen and phosphorus. The growth of plants can absorb nutrients in the water body and enhance the functions of the anode and cathode of the microbial electrochemical system through root exudates. The microbial electrochemical reaction can produce oxidizing substances such as chlorine, hydrogen peroxide, and free radicals, which can directly oxidize and destroy the structure and function of algal cells, leading to their death. In addition, the microbial electrochemical reaction can also reduce organic substances in the water body. Through the synergistic effect of these two mechanisms, the system can not only remove algae in the water body but also improve the water quality as a whole, enhancing the stability and sustainability of the water ecological environment. Detailed implementation mode

[0030] The following further elaborates on the above and additional technical features and advantages of the present invention in conjunction with embodiments.

[0031] Example 1

[0032] (1) Preparation method of the cathode electrode, comprising the following steps:

[0033] (a) Stir and mix Ti3AlC2 and hydrofluoric acid at a mass ratio of 1:2, react at 40 °C for 8 hours, and after the reaction is completed, repeatedly rinse with deionized water to remove residual hydrofluoric acid;

[0034] (b) Take 3 mg of the material obtained in step (a) and 150 mg of 1-propyl-3-methylimidazolium bromide and add them to 100 mL of deionized water, and treat with ultrasonic waves and stir evenly;

[0035] (c) Add 2 g of NH4VO3 to the mixture in step (b), and stir at high speed for 6 hours to obtain a composite material;

[0036] (d) Immerse the three-dimensional porous carbon nanoplates into the mixed solution in step (c), and the treatment time is 30 seconds. During this process, the vanadium-based hybrid material self-assembles on the carbon nanoplates to form an interlaced network. After drying and washing, thermally reduce at 200 °C for 2 hours to obtain the vanadium-based hybrid cathode electrode.

[0037] (2) Anaerobic biofilm attached to the anode surface: Take the bottom sediment (0 - 20 cm) of the urban landscape water body, mix the sediment and deionized water at a mass ratio of 1:2, and use the anaerobic sludge domesticated by the anaerobic reactor for inoculating the anode electrode.

[0038] (3) Arrange the anode electrode in the sediment, and the arrangement depth is 10 cm.

[0039] (4) Plant submerged plants at the position where the anode electrode is arranged, and the planting ratio of Potamogeton distinctus, Myriophyllum verticillatum, Vallisneria natans, and Ceratophyllum demersum is 1:2:1:3.

[0040] (5) Arrange the cathode electrode on the water surface, and connect the anode and the cathode with a stainless steel rod.

[0041] (6) Plant floating plants at the position where the cathode electrode is arranged, and the planting ratio of Nymphaea tetragona, Nymphoides peltata, and Eichhornia crassipes is 1:3:2. Before using the cathode electrode, perform a multi-layer grid treatment on it so that pores (pore diameter 2 - 4 mm) are evenly distributed on its surface to facilitate the roots of the floating plants to pass through and twine, and the multi-layer treatment makes the combination of the cathode and the roots of the floating plants closer.

[0042] Example 2

[0043] (1) Preparation method of the cathode electrode, comprising the following steps:

[0044] (a) Stir and mix Ti3AlC2 and hydrofluoric acid in a mass ratio of 1:3, react at 50 °C for 8 hours, and after the reaction is completed, rinse repeatedly with deionized water to remove residual hydrofluoric acid;

[0045] (b) Take 3 mg of the material obtained in step (a) and 150 mg of 1-propyl-3-methylimidazolium bromide and add them to 100 mL of deionized water, and treat with ultrasonic waves and stir evenly;

[0046] (c) Add 2 g of NH4VO3 to the mixture in step (b), stir at high speed for 8 hours to obtain a composite material;

[0047] (d) Immerse the three-dimensional porous carbon nanoplates into the mixed solution in step (c), and the treatment time is 50 seconds. During this process, the vanadium-based hybrid material self-assembles on the carbon nanoplates to form an interlaced network. After drying and washing, perform thermal reduction at 200 °C for 3 hours to obtain a vanadium-based hybrid cathode electrode.

[0048] (2) Attachment of anaerobic biofilm on the anode surface: Take the bottom sediment (0 - 20 cm) of urban landscape water, mix the sediment and deionized water in a mass ratio of 1:2, and use the anaerobic sludge domesticated in the anaerobic reactor for inoculation of the anode electrode.

[0049] (3) Arrange the anode electrode in the sediment, and the arrangement depth is 15 cm;

[0050] (4) Plant submerged plants at the position where the anode electrode is arranged, and the planting ratio of Potamogeton distinctus, Myriophyllum verticillatum, Vallisneria natans, and Ceratophyllum demersum is 1:1:2:2;

[0051] (5) Arrange the cathode electrode on the water surface, and connect the anode and the cathode with a stainless steel rod;

[0052] (6) Plant floating plants at the position where the cathode electrode is arranged, and the planting ratio of Nymphaea tetragona, Nymphoides peltatum, and Eichhornia crassipes is 1:2:3. Before use, perform multi-layer grid processing on the cathode electrode so that pores (pore diameter 2 - 4 mm) are evenly distributed on its surface to facilitate the roots of the floating plants to pass through and twine, and the multi-layer processing makes the combination between the cathode and the roots of the floating plants closer.

[0053] Example 3

[0054] (1) Preparation method of the cathode electrode, including the following steps:

[0055] (a) Stir and mix Ti3AlC2 and hydrofluoric acid in a mass ratio of 1:5, react at 60 °C for 10 hours, and after the reaction is completed, rinse repeatedly with deionized water to remove residual hydrofluoric acid;

[0056] (b) Add 3 mg of the material obtained in step (a) and 150 mg of 1-propyl-3-methylimidazolium bromide to 100 mL of deionized water, and treat with ultrasonic waves and stir evenly;

[0057] (c) Add 3 g of NH4VO3 to the mixture in step (b), stir at high speed for 8 hours to obtain a composite material;

[0058] (d) Immerse the three-dimensional porous carbon nanoplates into the mixed solution in step (c), and the treatment time is 50 seconds. During this process, the vanadium-based hybrid material self-assembles on the carbon nanoplates to form an interlaced network. After drying and washing, thermally reduce at 300 °C for 2 hours to obtain a vanadium-based hybrid cathode electrode.

[0059] (2) Attach an anaerobic biofilm to the anode surface: Take the sediment (0-20 cm) of the urban landscape water body, mix the sediment with deionized water at a mass ratio of 1:2, and use the anaerobic sludge domesticated by the anaerobic reactor for inoculating the anode electrode;

[0060] (3) Arrange the anode electrode in the sediment, and the arrangement depth is 15 cm;

[0061] (4) Plant submerged plants at the position where the anode electrode is arranged. The planting ratio of Potamogeton distinctus, Myriophyllum verticillatum, Vallisneria natans, and Ceratophyllum demersum is 1:3:1:2;

[0062] (5) Arrange the cathode electrode on the water surface, and connect the anode and the cathode with a stainless steel rod;

[0063] (6) Plant floating plants at the position where the cathode electrode is arranged. The planting ratio of Nymphaea tetragona, Nymphoides peltatum, and Eichhornia crassipes is 1:3:1. Before use, the cathode electrode is subjected to a multi-layer grid treatment so that pores with a pore size of 2-4 mm are evenly distributed on its surface to facilitate the roots of the floating plants to pass through and twine. The multi-layer treatment makes the combination of the cathode and the roots of the floating plants closer.

[0064] After operating for 60 days, the water bodies of Examples 1-3 were detected. The indexes of the river water body sample before treatment were: chlorophyll was 40.3 mg / m 3 ; the algal density was 3025×10 4 individuals / L; the total nitrogen was 1.65 mg / L; the total phosphorus was 0.22 mg / L. The detection results are shown in Table 1.

[0065] Table 1 Water body detection results of Examples 1-3

[0066]

[0067] As can be seen from Table 1, the plant-microbial electrochemical system developed in the present invention can effectively remove algae in water bodies and significantly improve water quality. This plant-microbial electrochemical system is easy to construct and apply. While controlling algae in urban landscape water bodies, it can also simultaneously remove pollutants such as nitrogen, phosphorus, and organic matter in water bodies and sediments. It has the characteristics of simple operation, low cost, and excellent treatment effect. The algae removal effect of Example 2 is significantly better than that of other examples, and its core advantage lies in the precise synergistic optimization of electrode material-plant function-system structure. In the preparation of the cathode, the reaction at a HF etching ratio of 1:3 + 50 °C may improve the electron mobility of the material. In terms of plant configuration, the proportion of Vallisneria natans increases, and the secreted citric acid, as an efficient electron shuttle, increases the expression level of extracellular electron transfer genes of anode microorganisms. In terms of system structure, a 15-cm anode burial depth creates a microaerobic-anaerobic transition zone, and rigid stainless steel connectors ensure the stability of the root-electrode interface. This multi-parameter synergy significantly improves the algae density removal rate, reflecting the irreplaceability of the process combination.

[0068] The above are only the preferred embodiments of the present invention, which are illustrative rather than restrictive to the present invention. Those skilled in the art understand that many changes, modifications, and even equivalents can be made within the spirit and scope defined by the claims of the present invention, but all will fall within the protection scope of the present invention.

Claims

1. A method for controlling algae in landscape water based on a plant-microbial electrochemical system, characterized in that It includes the following steps: S1. Arrange an anode electrode in the sediment, and the arrangement depth is 10 - 15 cm; S2. Plant submerged plants at the position where the anode electrode is arranged; S3. Arrange a cathode electrode on the water surface, and connect the anode and the cathode with a stainless steel rod; S4. Plant floating plants at the position where the cathode electrode is arranged.

2. The method for controlling algae in landscape water based on a plant-microbial electrochemical system according to claim 1, wherein In the step S1, the anode electrode is made of nickel-plated carbon felt. Before use, it is treated to make pores evenly distributed on its surface for the roots of plants to pass through, and the pore diameter is 2 - 4 mm.

3. The method for controlling algae in landscape water based on a plant-microbial electrochemical system according to claim 1, wherein In the step S1, an anaerobic biofilm is attached to the anode surface. The preparation method of the anaerobic biofilm is as follows: inoculate the anode electrode with anaerobic sludge obtained by domesticating in an anaerobic reactor of landscape water sediment suspension to obtain the anaerobic biofilm.

4. The method for controlling algae in landscape water based on a plant-microbial electrochemical system according to claim 3, characterized in that, The landscape water sediment suspension is prepared by mixing sediment and deionized water at a mass ratio of 1:1 to 1:

5.

5. The method for controlling algae in landscape water bodies based on a plant-microbial electrochemical system according to claim 1, characterized in that, In the step S2, the submerged plants include Potamogeton distinctus, Myriophyllum verticillatum, Vallisneria natans and Ceratophyllum demersum, and the planting ratio of Potamogeton distinctus, Myriophyllum verticillatum, Vallisneria natans, Ceratophyllum demersum is 1:1 - 3:1 - 2:2 - 3.

6. The method for controlling algae in landscape water based on a plant-microbial electrochemical system according to claim 1, characterized in that, In the step S3, the cathode electrode is a vanadium-based hybrid cathode material.

7. The method for controlling algae in landscape water based on a plant-microbial electrochemical system according to claim 6, wherein, The preparation method of the vanadium-based hybrid cathode material includes the following steps: S31. Stir and mix Ti3AlC2 and hydrofluoric acid, react at 40 - 60 °C for 6 - 10 hours, and after the reaction is completed, repeatedly rinse with deionized water to remove residual hydrofluoric acid; S32. Add the material obtained in the step S31 and 1-propyl-3-methylimidazolium bromide agent to deionized water, and treat with ultrasonic waves and stir evenly; S33. Add NH4VO3 to the mixture obtained in the step S32, stir for 6 - 8 h to obtain a composite material; S34. Immerse the three-dimensional porous carbon nanosheet into the composite material obtained in the step S33, the treatment time is 30 - 60 s, after drying and washing, thermally reduce it in an environment of 200 - 300 °C for 2 - 3 hours to obtain the vanadium-based hybrid cathode electrode.

8. The method for controlling algae in landscape water based on the plant-microbe electrochemical system according to claim 7, wherein In the step S31, the mass ratio of Ti3AlC2 to hydrofluoric acid is 1:2 - 1:

5.

9. The method for controlling algae in landscape water bodies based on a plant-microbial electrochemical system according to claim 7, wherein, In the step S32, the dosage of the material obtained in the step S31 is 3 mg, the dosage of 1-propyl-3-methylimidazolium bromide agent is 150 mg, and the dosage of deionized water is 100 mL.

10. The method for controlling algae in landscape water based on a plant-microbial electrochemical system according to claim 7, wherein, In the step S33, the dosage of NH4VO3 is 2 - 3 g.

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