Preparation method of a composite water treatment agent for aquaculture wastewater treatment

Abstract

The application discloses a preparation method of a composite water treatment agent for aquaculture wastewater treatment, and comprises the following steps: preparing nitrogen-phosphorus-sulfur ternary doped carbon spheres; ion liquid functionalization treatment; inner layer Cu-MOF growth; outer layer Zn / Cu-MOF growth; plasma treatment; and obtaining the composite water treatment agent. The ternary doped carbon sphere core in the composite water treatment provides abundant active sites through N, P and S synergic doping, the ion liquid functionalization significantly improves the hydrophilicity and ion exchange capacity of the material, promotes the rapid diffusion and adsorption of pollutants, the MOF in the inner layer Cu-rich region efficiently degrades organic matters through catalytic oxidation and simultaneously cooperatively treats ammonia nitrogen, and the outer layer Zn-rich region preferentially removes phosphate ions. The aquaculture wastewater treated by the composite water treatment agent can effectively remove organic pollutants and harmful substances such as nitrogen and phosphorus.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wastewater treatment, and particularly relates to a preparation method of a composite water treatment agent for aquaculture wastewater treatment. BACKGROUND

[0002] With the continuous expansion of the aquaculture industry, the problem of aquaculture wastewater discharge is becoming increasingly serious. Aquaculture wastewater usually contains a large amount of organic matter, nitrogen, phosphorus, antibiotics and other harmful substances. If it is directly discharged without effective treatment, it will cause serious pollution to the water environment, soil and ecological system, and even threaten human health. Therefore, how to efficiently and economically treat aquaculture wastewater has become a problem to be solved in the field of environmental protection.

[0003] At present, the methods for treating aquaculture wastewater mainly include physical method, chemical method and biological method. The physical method removes suspended solids and solid particles in wastewater through filtration, sedimentation, adsorption and other methods, but the removal effect of organic matter and antibiotics dissolved in water is poor. The chemical method removes harmful substances in water by adding chemical agents to react with pollutants in wastewater, but this method may cause secondary pollution and has high operating cost. The biological method relies on the metabolic action of microorganisms to degrade organic matter in water, which can effectively remove nitrogen, phosphorus and other pollutants, but the treatment period is long, and the water quality, temperature and environmental conditions are required.

[0004] Although the existing technology has solved the problem of removing nitrogen and phosphorus in aquaculture wastewater to some extent, there is still some difficulty in removing antibiotics, organic matter and composite pollutants in wastewater. The existing water treatment method is single, and lacks effective synergistic effect, which cannot solve the problem of removing multiple pollutants at the same time. Therefore, it is urgent to develop a new type of composite water treatment agent, which can form a synergistic effect between different pollutants, improve the efficiency of wastewater treatment, reduce the cost, and avoid the generation of secondary pollution. SUMMARY

[0005] Based on the problems in the background art, the present application provides a preparation method of a composite water treatment agent for aquaculture wastewater treatment. The use of the composite water treatment agent of the present application to treat aquaculture wastewater can effectively remove organic pollutants and harmful substances such as nitrogen and phosphorus, thereby improving water quality and reducing the impact of pollutants on aquatic ecological environment.

[0006] The present application is implemented by the following technical solutions:

[0007] A preparation method of a composite water treatment agent for aquaculture wastewater treatment, comprising the following steps:

[0008] S1. corn cob powder is soaked in a thiourea and urea aqueous solution, stirred, an aqueous ammonium dihydrogen phosphate solution is continuously added, stirred, and dried to obtain a mixture; the mixture is placed in a tube furnace, heat treated in a nitrogen atmosphere, and cooled to room temperature to obtain nitrogen-phosphorus-sulfur ternary doped carbon spheres;

[0009] S2. an ionic liquid ethanol solution is prepared, the nitrogen-phosphorus-sulfur ternary doped carbon spheres are added thereto, ultrasonically dispersed, stirred, suction filtered, washed, and dried to obtain functionalized carbon spheres;

[0010] S3. copper acetate is dissolved in an ethanol and water mixed solution, the functionalized carbon spheres are added thereto, ultrasonically dispersed, an ethanol solution of 1,3,5-benzenetricarboxylic acid is added dropwise, heated and stirred to react, a dispersion liquid is obtained, centrifuged, washed with ethanol, and surface Cu-MOF coated carbon spheres are obtained;

[0011] S4. copper acetate and zinc acetate are dissolved in an ethanol and water mixed solution, the surface Cu-MOF coated carbon spheres are added thereto, ultrasonically dispersed, an ethanol solution of 1,3,5-benzenetricarboxylic acid is added dropwise, heated and stirred to react, a dispersion liquid is obtained, centrifuged, washed with ethanol, and vacuum dried to obtain a pre-prepared composite water treatment agent;

[0012] S5. the pre-prepared composite water treatment agent is subjected to plasma treatment to obtain a composite water treatment agent.

[0013] Further, in step S1, the mass ratio of the use amounts of corn cob powder, thiourea and urea is 1:(0.4-0.8):(0.4-0.8); and the concentration of the thiourea and urea aqueous solution is 0.1-0.2 g / mL.

[0014] Further, in step S2, the mass ratio of the use amounts of ammonium dihydrogen phosphate and corn cob powder is (0.4-0.8):1.

[0015] Further, in step S1, the conditions of the tube furnace heat treatment are as follows: the temperature is raised to 500-550℃ at a rate of 5℃ / min, the temperature is maintained for 2 h, and the temperature is naturally cooled to room temperature.

[0016] Further, in step S2, the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid, and the concentration is 0.05-0.1 g / mL.

[0017] The mass ratio of the use amounts of ionic liquid and nitrogen-phosphorus-sulfur ternary doped carbon spheres is (0.2-0.3):1.

[0018] Further, in step S3, the mass ratio of the use amounts of copper acetate, 1,3,5-benzenetricarboxylic acid and functionalized carbon spheres is (0.8-0.95):(0.2-0.3):1.

[0019] Further, in step S3, the volume ratio of ethanol and water is 3:1; the concentration of copper acetate mixed solution is 0.07-0.1 g / mL; the concentration of 1,3,5-benzene tricarboxylic acid ethanol solution is 0.04-0.06 g / mL; and the heating temperature is 60℃.

[0020] Further, in step S4, the molar ratio of zinc acetate and copper acetate is (2-4):1; the mass ratio of the total amount of zinc acetate and copper acetate, 1,3,5-benzene tricarboxylic acid and the amount of surface Cu-MOF coated carbon spheres is (0.2-0.4):(0.1-0.2):1.

[0021] Further, in step S4, the volume ratio of ethanol and water is 3:1; the concentration of zinc acetate is 0.03-0.06 g / mL; the concentration of 1,3,5-benzene tricarboxylic acid ethanol solution is 0.04-0.06 g / mL; and the heating temperature is 70℃.

[0022] Further, in step S5, the specific conditions of the plasma treatment are as follows: in an oxygen atmosphere, the flow rate is 50 mL / min, the power is 200 W, and the treatment time is 5 min.

[0023] The beneficial effects of the present application are as follows:

[0024] The ternary doped carbon sphere core in the composite water treatment agent of the present application provides abundant active sites through N, P and S synergistic doping. The N doped sites promote ammonium ion adsorption, the P doped sites selectively bind metal ions, and the S doped sites enhance electron transfer and heavy metal chelating ability. The ionic liquid functionalization significantly improves the hydrophilicity and ion exchange capacity of the material, promoting the rapid diffusion and adsorption of pollutants. The MOF in the inner Cu-rich region efficiently degrades organic matter through catalytic oxidation, while simultaneously treating ammonia nitrogen; the outer Zn-rich region preferentially removes phosphate ions. This spatially separated structure design avoids mutual interference between different treatment processes, achieving the synergistic removal of pollutants. DETAILED DESCRIPTION

[0025] The technical solutions of the present application will be further described below in combination with specific embodiments, but the protection scope of the present application is not limited to the following embodiments.

[0026] Example 1

[0027] A preparation method of a composite water treatment agent for aquaculture wastewater treatment, comprising the following steps:

[0028] S1. Dissolve 100 g thiourea and 100 g urea in 1 L deionized water, add 200 g corncob powder, stir at room temperature for 12 h, continue to add 100 g ammonium dihydrogen phosphate, stir at room temperature for 4 h, dry at 80℃, to obtain a mixture; place the mixture in a tube furnace, heat treat in a nitrogen atmosphere, i.e. heat to 500℃ at 5℃ / min, keep for 2 h, naturally cool to room temperature, to obtain nitrogen-phosphorus-sulfur ternary doped carbon spheres;

[0029] S2. Dissolve 25 g 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid in 1 L anhydrous ethanol, add 100 g nitrogen-phosphorus-sulfur ternary doped carbon spheres, ultrasonic dispersion, stirring, suction filtration, washing, drying, to obtain functionalized carbon spheres;

[0030] S3. Dissolve 75 g copper acetate in 750 mL mixed solution of ethanol and water, add 80 g functionalized carbon spheres, ultrasonic dispersion, dropwise add 400 mL ethanol solution of 21 g 1,3,5-benzenetricarboxylic acid, heat to 60℃, stirring reaction, to obtain a dispersion, centrifugal separation, ethanol washing, to obtain surface Cu-MOF coated carbon spheres;

[0031] S4. Dissolve 18 g zinc acetate and 9 g copper acetate in 300 mL mixed solution of ethanol and water, add surface Cu-MOF coated carbon spheres, ultrasonic dispersion, dropwise add 250 mL ethanol solution of 12 g 1,3,5-benzenetricarboxylic acid, heat to 70℃, stirring reaction, to obtain a dispersion, centrifugal separation, ethanol washing, vacuum drying, to obtain a pre-prepared composite water treatment agent;

[0032] S5. Plasma treat the pre-prepared composite water treatment agent, i.e. treat in an oxygen atmosphere, flow rate 50 mL / min, power 200 W, for 5 min, to obtain a composite water treatment agent.

[0033] Example 2

[0034] The difference between this example and Example 1 is that in step S4, the amount of zinc acetate is 19.5 g, and the amount of copper acetate is 7.5 g, and the remaining steps are the same as in Example 1.

[0035] Example 3

[0036] Preferably, after adding carbon spheres to the corresponding solution and ultrasonic dispersion in S2, S3 and / or S4, take a preset volume of the target solution to perform DLS (Dynamic Light Scattering) test:

[0037] Irradiate the target solution to be tested with a laser;

[0038] The scattered light signal is collected by a photomultiplier tube or an avalanche photodiode; wherein the sampling time interval is in the order of nanoseconds or microseconds;

[0039] An intensity-time image is constructed based on the collected scattered light signal, and the post-sampling signal after a preset time length is compared with the initial sampling signal to obtain a comparison result;

[0040] Based on the intensity-time image and the comparison result, an auto-correlation function C(T) is constructed to determine the particle decay constant T;

[0041] Based on the particle decay constant T, the diffusion coefficient D is determined:

[0042] 1 / T=2DK

[0043] Wherein, K is the scattered light wave vector;

[0044] Further, Wherein, n is the refractive index of the solvent; λ is the laser wavelength; θ is the scattering angle, and θ=90° when DLS is performed;

[0045] According to the diffusion coefficient D, the particle size is determined, and it is judged whether the particle size meets the preset size threshold value; if yes, the ultrasonic dispersion is stopped, and the preparation process is continued; if not, the ultrasonic dispersion and DLS test are performed again until the particle size in the solution meets the preset size threshold value.

[0046] Comparative Example 1

[0047] The difference between this comparative example and Example 1 is that in step S1, 300 g of urea is dissolved in 1 L of deionized water, 200 g of corn cob powder is added, and stirring is performed at room temperature for 12 h, and the remaining steps are the same as in Example 1.

[0048] Comparative Example 2

[0049] The difference between this comparative example and Example 1 is that step S2 is not included, i.e., after obtaining the nitrogen-phosphorus-sulfur ternary doped carbon spheres, a mixed solution of copper acetate in ethanol and water is directly added to prepare the carbon spheres coated with surface Cu-MOF; and the ionic liquid surface functionalization treatment is not included.

[0050] Comparative Example 3

[0051] The difference between this comparative example and Example 1 is that step S4 is not included, i.e., after obtaining the carbon spheres coated with surface Cu-MOF, plasma treatment is directly performed.

[0052] Comparative Example 4

[0053] The difference between this comparative example and Example 1 is that steps S1 and S2 are the same as in Example 1,

[0054] The specific operation of step S3 is: 84 g of copper acetate and 18 g of zinc acetate are dissolved in a mixed solution of 750 mL of ethanol and 250 mL of water, 80 g of functionalized carbon spheres are added and ultrasonically dispersed, 600 mL of an ethanol solution containing 33 g of 1,3,5-benzene tricarboxylic acid is added dropwise, and the reaction is stirred at 70°C to obtain a dispersion liquid, which is centrifuged and washed with ethanol to obtain a pre-prepared composite water treatment agent.

[0055] S5. The pre-prepared composite water treatment agent is subjected to plasma treatment, i.e. treatment under an oxygen atmosphere at a flow rate of 50 mL / min and a power of 200 W for 5 min, to obtain a composite water treatment agent.

[0056] Test Example

[0057] Effect of water treatment agents in Examples 1-2 and Comparative Examples 1-4 on aquaculture wastewater treatment

[0058] An artificial aquaculture wastewater is used, wherein the main pollutant concentrations are as follows: total phosphorus concentration 10 mg / L, ammonia nitrogen concentration 20 mg / L, COD 300 mg / L, and ciprofloxacin concentration 10 mg / L. The composition and concentration of the substances used for preparation are as follows: glucose 500 mg / L, ammonium sulfate 94.38 mg / L, potassium dihydrogen phosphate 14.32 mg / L, and ciprofloxacin 10 mg / L.

[0059] Determination of pollutants in aquaculture wastewater

[0060] (1) Ammonia nitrogen: determined according to the determination method of National Standard Nessler's reagent spectrophotometry HJ535-2009.

[0061] (2) Total phosphorus: determined according to the determination method of molybdenum acid ammonium photometry GB 11893-1989.

[0062] (3) COD: determined according to the determination method of alkaline potassium permanganate GB 11893-1989.

[0063] (4) Ciprofloxacin: high performance liquid chromatograph, using a C-18 solid phase extraction column, a mobile phase of 0.025 mol·L -1 of phosphoric acid aqueous solution: acetonitrile = 87:13 (V:V) at a flow rate of 1.5 ml·min -1 , and detection at a wavelength of 278 nm.

[0064] The water treatment agents in Examples 1-2 and Comparative Examples 1-4 are mixed with the prepared aquaculture wastewater at a dosage of 2 g per liter of wastewater, stirred at room temperature, and sampled after 2 h of reaction to determine the contents of ammonia nitrogen, total phosphorus, COD, and ciprofloxacin in the water sample, and calculate the removal rates of ammonia nitrogen, total phosphorus, COD, and ciprofloxacin. The specific results are shown in Table 1.

[0065] Table 1

[0066]

[0067]

[0068] As can be seen from the results in Table 1, the composite water treatment agent prepared using the present application can effectively remove organic pollutants and harmful substances such as nitrogen and phosphorus when used to treat aquaculture wastewater, thereby improving water quality and reducing the impact of pollutants on aquatic ecological environment. The composite water treatment agent is also tested for its recycling performance in the present application, and the material has excellent reusability. After simple regeneration treatment (acid washing-alkali washing-water washing), the material can be recycled for 8-10 times, and the removal rates of ammonia nitrogen, total phosphorus, COD and ciprofloxacin remain above 88% after the 10th use.

[0069] In Comparative Example 1, only urea was used to treat corn cob powder without adding thiourea, and the carbon spheres in the finally prepared composite water treatment agent did not contain sulfur doping. In terms of ammonia nitrogen treatment, the lack of sulfur doping caused the synergistic effect of sulfur doping on improving the electrical conductivity of the material to disappear, reducing the electron transfer efficiency and lowering the catalytic oxidation conversion rate of ammonia nitrogen. The initial total phosphorus removal performance was not greatly affected, although the phosphate adsorption mechanism of the outer Zn-MOF was not changed, but the lack of sulfur doping weakened the overall stability of the material, which might cause part of the MOF structure to be lost, affecting the long-term operation effect. Through the recycling test, it was found that the total phosphorus removal rate was 85.57% after 10 cycles. In terms of COD treatment, the lack of sulfur doping reduced the electron conduction ability of the material, affecting the efficiency of the Cu active center to produce active oxygen, and lowering the COD removal capacity. The selective adsorption capacity of the composite water treatment agent without sulfur doping for antibiotics decreased, and the removal rate of antibiotics also decreased.

[0070] In Comparative Example 2, no ionic liquid functionalization treatment was performed, which would directly affect the interface properties of the material and the wastewater treatment effect. In terms of ammonia nitrogen treatment, due to the lack of additional ion exchange sites provided by the ionic liquid, the ammonia nitrogen adsorption capacity was reduced, and at the same time, the surface hydrophilicity of the water treatment agent was reduced, affecting the diffusion and contact efficiency of NH 4+ In terms of total phosphorus, due to the reduced surface hydrophilicity of the water treatment agent, the dispersion performance of the water treatment agent in the water phase was reduced, and agglomeration was prone to occur, resulting in a certain reduction in the total phosphorus removal rate. The ionic liquid in the present application scheme enhances the hydrophilicity of the material and provides ion channels to promote the contact of organic molecules with the catalytically active sites. After the ionic liquid functionalization, the surface hydrophobicity of the water treatment agent is enhanced, and the organic pollutants are difficult to effectively contact the Cu active center, affecting the catalytic oxidation efficiency and thus reducing the COD treatment rate. The imidazole ring structure of the ionic liquid can enhance the adsorption of antibiotics containing aromatic rings through π-π stacking, and at the same time, the BF 4-The charge effect provided by anions helps the binding of polar antibiotics. After losing this interface functionalization, the selective adsorption capacity of the material for tetracycline and quinolone antibiotics decreases significantly.

[0071] In Comparative Example 3, the outer layer of Zn / Cu-MOF growth layer is absent. In terms of ammonia-nitrogen treatment, only the Cu-MOF layer can still realize the adsorption and conversion of ammonium ions through the synergistic effect of Cu active centers and N-doped sites, and the ammonia-nitrogen removal rate decreases to a certain extent. Without the outer layer of Zn-rich region, the material loses the active sites for efficient chelation of phosphate. Although Cu-MOF also has a certain adsorption capacity for phosphate, the selectivity and binding stability are much lower than Zn-MOF, and the total phosphorus removal rate decreases significantly. The COD removal rate does not change significantly at the beginning, and Cu-MOF has good catalytic oxidation performance and can generate sufficient active oxygen species to degrade organic matter after plasma activation. However, due to the lack of protection of the outer MOF layer, the active components are easily lost, and after 10 cycles of use, the COD removal rate is only 84.14%. In terms of antibiotic removal, the performance also decreases to a certain extent. In the present application, the dual-metal MOF structure provides multiple active sites. The inner Cu-MOF degrades antibiotics through catalytic oxidation, and the outer Zn-MOF realizes adsorption through coordination. After losing this synergistic effect, the antibiotic removal rate decreases.

[0072] In Comparative Example 4, Cu and Zn are introduced simultaneously for MOF growth. In terms of ammonia-nitrogen treatment, due to the random distribution of Cu and Zn active sites, the catalytic oxidation efficiency of Cu active centers is disturbed by Zn, and the advantage of spatial separation is also lost, resulting in a decrease in ammonia-nitrogen removal rate. In addition, competition coordination of metal ions may occur during treatment, affecting the stability of the treatment effect. The random distribution of metal sites weakens the coordination effect of Zn and phosphate, and the presence of Cu interferes with the selective binding of phosphate, so the total phosphorus removal effect decreases. The Cu active center is diluted by Zn, the active oxygen production capacity is weakened, and the deep oxidation effect of the inner Cu-rich region is lost, so the COD treatment is significantly affected. In terms of antibiotic treatment, the spatial separation of the dual-action mechanism is lost, and neither the catalytic degradation effect of Cu nor the selective adsorption of Zn can be fully utilized. The selectivity of the water treatment agent for antibiotics decreases significantly, the treatment efficiency is unstable, and it is easily affected by water quality fluctuations.

[0073] Finally, it should be noted that the above-described examples only express several embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made by those skilled in the art without departing from the concept of the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A method for preparing a composite water treatment agent for aquaculture wastewater treatment, characterized by, The method comprises the following steps: S1. corn cob powder is soaked in a thiourea and urea aqueous solution, stirred, an aqueous ammonium dihydrogen phosphate solution is continuously added, stirred, and dried to obtain a mixture; the mixture is placed in a tube furnace for heat treatment in a nitrogen atmosphere, and cooled to room temperature to obtain nitrogen-phosphorus-sulfur ternary doped carbon spheres; S2. an ionic liquid ethanol solution is prepared, the nitrogen-phosphorus-sulfur ternary doped carbon spheres are added and ultrasonically dispersed, stirred, suction filtered, washed, and dried to obtain functionalized carbon spheres; S3. copper acetate is dissolved in an ethanol and water mixed solution, the functionalized carbon spheres are added and ultrasonically dispersed, an ethanol solution of 1,3,5-benzenetricarboxylic acid is added dropwise, heated and stirred to react to obtain a dispersion liquid, centrifuged, washed with ethanol, and surface Cu-MOF coated carbon spheres are obtained; S4. zinc acetate and copper acetate are dissolved in an ethanol and water mixed solution, the surface Cu-MOF coated carbon spheres are added and ultrasonically dispersed, an ethanol solution of 1,3,5-benzenetricarboxylic acid is added dropwise, heated and stirred to react to obtain a dispersion liquid, centrifuged, washed with ethanol, vacuum dried, and a prefabricated composite water treatment agent is obtained; S5. the prefabricated composite water treatment agent is subjected to plasma treatment to obtain a composite water treatment agent. The ionic liquid in step S2 is 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid.

2. The preparation method of the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S1, the mass ratio of the corn cob powder, thiourea and urea is (0.4-0.8) :(0.4-0.8) :(0.4-0.8); and the concentration of the thiourea and urea aqueous solution is 0.1-0.2 g / mL.

3. The preparation method of the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S2, the mass ratio of the amount of ammonium dihydrogen phosphate to the amount of corn cob powder is (0.4-0.8) :

1.

4. The preparation method of the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S1, the conditions for the tube furnace heat treatment are as follows: the temperature is raised to 500-550 ℃ at a rate of 5 ℃ / min, the temperature is maintained for 2 h, and the temperature is naturally cooled to room temperature.

5. The preparation method of the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S2, the concentration of the ionic liquid is 0.05-0.1 g / mL. The mass ratio of the amount of ionic liquid to the amount of nitrogen-phosphorus-sulfur ternary doped carbon spheres is (0.2-0.3) :

1.

6. The preparation method of the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S3, the mass ratio of the amount of copper acetate, 1,3,5-benzenetricarboxylic acid and functionalized carbon spheres is (0.8-0.95) :(0.2-0.3) :

1.

7. The preparation method of the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S3, the volume ratio of ethanol to water is 3:1; the concentration of the copper acetate mixed solution is 0.07-0.1 g / mL; the concentration of the 1,3,5-benzenetricarboxylic acid ethanol solution is 0.04-0.06 g / mL; and the heating temperature is 60 ℃.

8. The method for preparing the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S4, the molar ratio of zinc acetate to copper acetate is (2-4) : 1; and the mass ratio of the total amount of zinc acetate and copper acetate, 1,3,5-benzenetricarboxylic acid and surface Cu-MOF coated carbon spheres is (0.2-0.4) :(0.1-0.2) :

1.

9. The method for preparing the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S4, the volume ratio of ethanol to water is 3:1; the concentration of the zinc acetate is 0.03-0.06 g / mL; the concentration of the 1,3,5-benzenetricarboxylic acid ethanol solution is 0.04-0.06 g / mL; and the heating temperature is 70 ℃.

10. The method for preparing the complex water treatment agent for aquaculture wastewater treatment according to claim 1, characterized in that, In step S5, the specific conditions for the plasma treatment are as follows: the treatment is carried out in an oxygen atmosphere at a flow rate of 50 mL / min and a power of 200 W for 5 min.

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