A method for treating nicotine pesticides in water

Abstract

The present application relates to the field of pesticide treatment, and specifically discloses a method for treating nicotine pesticides in water, comprising the following steps: S1, adding a polydopamine-modified macroporous resin to water, subjecting the water to a dispersion adsorption treatment and a freezing treatment to obtain preliminary purified water; S2, thawing the preliminary purified water, adding carboxyl-modified carbon nanotubes, subjecting the water to a dispersion adsorption treatment, and collecting the liquid to obtain purified water; thereby reducing the content of nicotine pesticides in the water.

Description

Technical Field

[0001] The present application relates to the field of pesticide treatment, and more specifically, to a method for treating nicotine pesticides in water. Background Art

[0002] Nicotine pesticides are a type of insecticide that acts on insects. They have the advantages of high efficiency, broad spectrum, and strong systemic properties. After acting on crops and vegetables, most of the nicotine pesticides enter the soil and are then washed through the surface by rainwater into the water environment.

[0003] Nicotine pesticides are generally divided into N-nitroguanidines (imidacloprid, clothianidin, thiamethoxam and dinotefuran), nitromethylenes (nitrimide) and N-cyanoamidines (acetamiprid and thiacloprid); neonicotinoid pesticides that enter the water will have toxic effects on aquatic organisms. Among them, aquatic invertebrates are more sensitive to pesticide pollution, and aquatic insects are the most sensitive. The main reason is that neonicotinoid pesticides bind to the nicotinic acetylcholine receptors on the postsynaptic membrane of the insect central nervous system, leading to receptor blockade, paralysis and death; at the same time, fish health is also threatened. Studies have found that imidacloprid can induce a significant increase in the content of reactive oxygen species in zebrafish, leading to disorders in its antioxidant enzyme system, causing lipid peroxidation and genetic damage; and as humans are at the top of the food chain, these nicotinoid pesticides will eventually enter the human body through diet, drinking water and other pathways. In the long run, it is easy to have an impact on human health.

[0004] Therefore, how to reduce nicotine pesticides in water is an issue that needs to be addressed. Summary of the Invention

[0005] In order to reduce nicotine pesticides in water, the present application provides a method for treating nicotine pesticides in water.

[0006] This application provides a method for treating nicotine pesticides in water, which adopts the following technical solution:

[0007] A method for treating nicotine pesticides in water comprises the following steps:

[0008] S1. Adding polydopamine-modified macroporous resin to water, and performing dispersion adsorption treatment and freezing treatment to obtain preliminary purified water;

[0009] S2. Preliminary purification: After the water is thawed, carboxyl-modified carbon nanotubes are added, and then the water is subjected to dispersion and adsorption treatment, and the liquid is taken to obtain purified water.

[0010] By adopting the above technical solution, polydopamine-modified macroporous resin, freezing treatment, thawing, and carboxyl-modified carbon nanotubes are combined. The polydopamine-modified macroporous resin first adsorbs nicotine pesticides, and then the freezing treatment combined with thawing promotes the polydopamine-modified macroporous resin to further adsorb nicotine pesticides while facilitating adhesion with the carboxyl-modified carbon nanotubes, forming a structure in which the carboxyl-modified carbon nanotubes are attached to the surface of the polydopamine-modified macroporous resin. The adsorption effect of the carboxyl-modified carbon nanotubes on nicotine pesticides is utilized to further reduce the content of nicotine pesticides in water. In addition, the adhesion between large particles facilitates filtration, thereby obtaining purified water, and the content of nicotine pesticides in the purified water is low.

[0011] The macroporous resin utilizes its higher porosity and better adsorption effect to facilitate the adsorption of nicotine pesticides. Combined with the attraction and adsorption of nicotine pesticides by the amino groups in polydopamine, the polydopamine-modified macroporous resin is further promoted to adsorb nicotine pesticides in water. Then, after freezing treatment, water crystallizes to produce an ice thorn structure. The thorn-like structure of ice facilitates penetration into the polydopamine-modified macroporous resin, and the pores in the polydopamine-modified macroporous resin are prevented as much as possible from being blocked by the adsorbed nicotine pesticides, which affects the subsequent adsorption and connection effects.

[0012] After thawing, the ice thorn structure disappears, and the polydopamine-modified macroporous resin can adsorb nicotine pesticides again. With the addition of carboxyl-modified carbon nanotubes, the carboxyl groups on the surface of the carboxyl-modified carbon nanotubes and the amino groups on the surface of the polydopamine-modified macroporous resin attract and bond with each other, so that the carboxyl-modified carbon nanotubes can adhere to the surface of the polydopamine-modified macroporous resin, thereby blocking the nicotine pesticides adsorbed by the polydopamine-modified macroporous resin and trying to prevent the adsorbed nicotine pesticides from being released into the water again. At the same time, the adhesion between the polydopamine-modified macroporous resin and the carboxyl-modified carbon nanotubes increases the surface area and volume of the particles, thereby facilitating the filtration and discharge of the carboxyl-modified carbon nanotubes and the polydopamine-modified macroporous resin to obtain purified water.

[0013] The adsorption effect of carbon nanotubes in carboxyl-modified carbon nanotubes on nicotine pesticides is utilized, and the electron-donating property of the carboxyl groups on the surface of the carbon nanotubes is combined to promote the increase of the electron cloud density on the benzene ring, thereby improving the adsorption efficiency and adsorption amount of the carbon nanotubes on nicotine pesticides. In addition, the carboxyl modification of the carbon nanotubes increases the specific surface area and porosity of the carbon nanotubes, thereby further improving the adsorption efficiency and adsorption amount of the carboxyl-modified carbon nanotubes on nicotine pesticides. At the same time, the carboxyl-modified carbon nanotubes can improve the dispersibility of the carbon nanotubes in water, and prevent the carbon nanotubes from agglomerating to the greatest extent possible and affecting the adsorption effect of the carbon nanotubes, thereby preventing the carboxyl-modified carbon nanotubes and the polydopamine-modified macroporous resin from agglomerating to the greatest extent and affecting the adsorption effect, thereby further reducing the content of nicotine pesticides in water.

[0014] Preferably, the polydopamine-modified macroporous resin is prepared by soaking macroporous resin in a polydopamine solution.

[0015] By adopting the above technical solution, the porous structure of the macroporous resin and its good adsorption effect are utilized to facilitate the adsorption of the polydopamine solution, so that the polydopamine solution enters the interior of the macroporous resin, thereby causing the polydopamine to adhere to the interior and surface of the macroporous resin. The macroporous resin is modified by polydopamine, which not only increases the specific surface area of the macroporous resin, but also increases the adsorption efficiency of the polydopamine-modified macroporous resin for nicotine pesticides, thereby further reducing the nicotine pesticide content in water.

[0016] Preferably, the polydopamine solution is composed of a polydopamine aqueous solution and a carboxymethyl chitosan aqueous solution in a mass ratio of 1:0.1-0.5.

[0017] By adopting the above technical solution, a polydopamine aqueous solution and a carboxymethyl chitosan aqueous solution are combined, and the amino groups in polydopamine are combined with the carboxyl groups and amino groups in carboxymethyl chitosan to facilitate the formation of a network structure on the surface of the macroporous resin, thereby increasing the specific surface area of the macroporous resin and improving the adsorption efficiency and adsorption capacity of the macroporous resin for nicotinic pesticides. Moreover, the presence of groups such as amino and carboxyl groups can further improve the adsorption capacity of the macroporous resin for nicotinic pesticides; and carboxymethyl chitosan has certain disinfection and sterilization efficiency, can kill bacteria in water, and improve water safety; at the same time, the combination of carboxymethyl chitosan and polydopamine can further promote the adhesion of carboxyl-modified carbon nanotubes to the surface of the polydopamine-modified macroporous resin, improving the adsorption efficiency while facilitating the discharge of adsorbed particles, thereby improving the purity of the water.

[0018] Preferably, the carboxyl-modified carbon nanotubes are prepared by the following method:

[0019] Weigh carbon nanotubes and place them in a polylysine solution for immersion and dispersion. Then take out the carbon nanotubes and evenly spray sticky carbon aerogel on the surface of the carbon nanotubes. The mass ratio of carbon nanotubes to sticky carbon aerogel is 1:0.05-0.2. After drying and dispersion, the finished carboxyl-modified carbon nanotubes are obtained.

[0020] By adopting the above technical solution, carbon nanotubes, polylysine solution, and sticky carbon aerogel are combined, and the sticky carbon aerogel is bonded to the surface of the carbon nanotubes modified with the carboxyl groups of polylysine, forming a structure in which the carbon nanotubes are used as a base and the surface of the carbon nanotubes is coated with the sticky carbon aerogel. The sticky carbon aerogel utilizes the larger porosity and better adsorption effect to facilitate the adsorption of nicotine pesticides in water. In addition, the adsorption effect of the carbon nanotubes is utilized to give the carboxyl-modified carbon nanotubes a larger surface area, resulting in a larger adsorption amount of nicotine pesticides in water.

[0021] By limiting the amount of sticky carbon aerogel added, the surface of the carbon nanotubes is not completely covered by the sticky carbon aerogel, and the surface polylysine is partially exposed. The carboxyl groups in the polylysine are used to attract and bond with the amino groups on the surface of the polydopamine-modified macroporous resin to form large particles. The large particles use the polydopamine-modified macroporous resin as a substrate, and the carboxyl-modified carbon nanotubes are attached to the surface. The presence of partial sticky carbon aerogel on the surface of the carboxyl-modified carbon nanotubes makes the specific surface area of the large particles larger, further improving the adsorption effect of the large particles and reducing the content of nicotine pesticides in water.

[0022] Preferably, the viscous carbon aerogel is composed of carbon aerogel and polyvinyl alcohol aqueous solution in a mass ratio of 1:0.1-0.28.

[0023] By adopting the above technical solution, polyvinyl alcohol is loaded on the surface of the carbon aerogel, and the viscosity of the polyvinyl alcohol aqueous solution is utilized to facilitate the adhesion of the carbon aerogel to the surface of the carbon nanotube loaded with polylysine. The cross-linking effect of the polyvinyl alcohol aqueous solution and the polylysine solution is utilized to facilitate the formation of a bonding cross-linked network on the surface of the carbon nanotube, further improving the surface porosity of the carboxyl-modified carbon nanotubes while facilitating the mutual attraction and connection between the carboxyl groups and hydroxyl groups in the carboxyl-modified carbon nanotubes and the amino groups on the surface of the polydopamine-modified macroporous resin. This not only improves the adsorption effect of nicotine pesticides in water, but also facilitates the filtration of the polydopamine-modified macroporous resin and the carboxyl-modified carbon nanotubes, thereby improving the purity of the water.

[0024] Preferably, the particle size of the polydopamine-modified macroporous resin is 100-250 μm, and the particle size of the carboxyl-modified carbon nanotube is 2-10 μm.

[0025] By adopting the above technical solution, the particle size of the polydopamine-modified macroporous resin is relatively large, while the particle size of the carboxyl-modified carbon nanotube is relatively small. By utilizing the bonding of the two, large particles are formed, which are convenient for filtration to obtain purified water. In addition, the 2-10 μm carboxyl-modified carbon nanotubes facilitate blocking part of the pores of the polydopamine-modified macroporous resin, thereby minimizing the release of nicotine pesticides adsorbed by the polydopamine-modified macroporous resin into the water, thereby affecting the content of nicotine pesticides in the water.

[0026] Preferably, the freezing treatment temperature is -40 to -20°C, and the freezing time is 24 to 48 hours.

[0027] By adopting the above technical solution, the freezing temperature and freezing time are limited to ensure that water crystals penetrate into the pores and surface of the polydopamine-modified macroporous resin. The penetration of ice crystals not only facilitates increasing the porosity of the macroporous resin, but also facilitates connecting the pores, thereby minimizing the clogging of the pores after the macroporous resin adsorbs nicotine pesticides, thereby affecting the subsequent adsorption and bonding effects.

[0028] Preferably, the temperature is raised to 35-45° C. after thawing, and then the carboxyl-modified carbon nanotubes are added.

[0029] By adopting the above technical solution, the temperature is raised after thawing, which promotes the bonding between the polydopamine-modified macroporous resin and the carboxyl-modified carbon nanotubes, thereby improving the adsorption efficiency and adsorption amount of nicotine pesticides in water.

[0030] Preferably, the dispersion adsorption treatment in S1 is carried out by stirring at 500-1000 r / min for 24-48 hours.

[0031] By adopting the above technical solution, the stirring speed and time are limited to ensure uniform dispersion while making the polydopamine-modified macroporous resin have a larger adsorption rate, thereby reducing the nicotine pesticide content in water.

[0032] Preferably, in the dispersion adsorption treatment in S2, first stirring at a speed of 500-1000 r / min for 30-90 min, then stirring at a speed of 120-250 r / min for 12-24 h, and finally standing for 2-6 h.

[0033] By adopting the above technical solution, high-speed stirring is first performed to allow the carboxyl-modified carbon nanotubes to be evenly dispersed and adsorption to be completed, and then low-speed stirring is performed to facilitate the combination and sedimentation of the carboxyl-modified carbon nanotubes and the polydopamine-modified macroporous resin, and finally the mixture is allowed to stand to facilitate layered filtration to obtain purified water.

[0034] In summary, this application has the following beneficial effects:

[0035] 1. Polydopamine-modified macroporous resin, freezing treatment, thawing, and carboxyl-modified carbon nanotubes are combined. The polydopamine-modified macroporous resin first adsorbs nicotine pesticides. Then, the freezing treatment combined with thawing promotes the polydopamine-modified macroporous resin to further adsorb nicotine pesticides while facilitating adhesion with the carboxyl-modified carbon nanotubes to form a structure in which the carboxyl-modified carbon nanotubes are attached to the surface of the polydopamine-modified macroporous resin. The adsorption effect of the carboxyl-modified carbon nanotubes on nicotine pesticides is utilized to further reduce the content of nicotine pesticides in water. In addition, the adhesion between large particles facilitates filtration, thereby obtaining purified water. The content of nicotine pesticides in the purified water is low.

[0036] 2. Carbon nanotubes, polylysine solution, and sticky carbon aerogel are combined. The sticky carbon aerogel is bonded to the surface of the carbon nanotubes using the polylysine solution, forming a structure in which the carbon nanotubes are inside and the surface of the carbon nanotubes is covered with the sticky carbon aerogel. The sticky carbon aerogel has a larger porosity and better adsorption effect, which facilitates the adsorption of nicotine pesticides in water. In addition, the adsorption effect of the carbon nanotubes is utilized to give the carboxyl-modified carbon nanotubes a larger surface area, resulting in a larger adsorption amount of nicotine pesticides in water.

[0037] 3. The particle sizes of the polydopamine-modified macroporous resin and the carboxyl-modified carbon nanotubes are limited. The carboxyl-modified carbon nanotubes facilitate blocking some of the pores of the polydopamine-modified macroporous resin, thereby minimizing the release of nicotine pesticides adsorbed by the polydopamine-modified macroporous resin into the water and affecting the content of nicotine pesticides in the water. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the embodiments.

[0039] Preparation Example of Polydopamine Solution

[0040] The polydopamine in the following raw materials was purchased from Xi'an Qiyue Biotechnology Co., Ltd.; carboxymethyl chitosan was purchased from Jiangsu Duoyang Bioengineering Technology Co., Ltd., which produces water-soluble carboxymethyl chitosan; other raw materials and equipment were commercially available.

[0041] Preparation Example 1: Polydopamine solution was prepared by the following method:

[0042] 1 kg of polydopamine aqueous solution and 0.32 kg of carboxymethyl chitosan aqueous solution were weighed and mixed and stirred uniformly to prepare a polydopamine solution; the mass fraction of the polydopamine aqueous solution was 10%; the mass fraction of the carboxymethyl chitosan aqueous solution was 2%.

[0043] Preparation Example 2: This preparation example differs from Preparation Example 1 in that:

[0044] 1 kg of polydopamine aqueous solution and 0.1 kg of carboxymethyl chitosan aqueous solution were weighed and mixed and stirred uniformly to prepare a polydopamine solution.

[0045] Preparation Example 3: This preparation example differs from Preparation Example 1 in that:

[0046] 1 kg of polydopamine aqueous solution and 0.5 kg of carboxymethyl chitosan aqueous solution were weighed and mixed and stirred uniformly to prepare a polydopamine solution.

[0047] Preparation example of polydopamine modified macroporous resin

[0048] The macroporous resin in the following raw materials was purchased from Shanghai Yuanye Biotechnology Co., Ltd.; other raw materials and equipment were commercially available.

[0049] Preparation Example 4: Polydopamine-modified macroporous resin was prepared by the following method:

[0050] The macroporous resin was weighed and placed in the polydopamine solution prepared in Preparation Example 1, and the mixture was dispersed and stirred. The mixture was ultrasonically dispersed at 20 kHz for 30 minutes, and then the macroporous resin was filtered out and dried to obtain a finished polydopamine-modified macroporous resin. The particle size of the polydopamine-modified macroporous resin was 150 μm.

[0051] Preparation Example 5: This preparation example differs from Preparation Example 4 in that:

[0052] The polydopamine solution is the polydopamine solution prepared in Preparation Example 2; the particle size of the polydopamine-modified macroporous resin is 100 μm.

[0053] Preparation Example 6: This preparation example differs from Preparation Example 4 in that:

[0054] The polydopamine solution is the polydopamine solution prepared in Preparation Example 3; the particle size of the polydopamine-modified macroporous resin is 250 μm.

[0055] Preparation Example of Carboxyl-Modified Carbon Nanotubes Among the following raw materials, polylysine was purchased from food-grade ε-polylysine produced by Guangzhou Huayu Biotechnology Co., Ltd.; polyvinyl alcohol was purchased from food-grade polyvinyl alcohol produced by Guangzhou Hongzhou Chemical Co., Ltd.; other raw materials and equipment were commonly available on the market.

[0056] Preparation Example 7: Carboxyl-modified carbon nanotubes were prepared by the following method:

[0057] Weigh polylysine, place it in water and stir until it is completely dissolved to prepare a 5% polylysine solution;

[0058] 18 g of polyvinyl alcohol aqueous solution was evenly sprayed on the surface of 100 g of carbon aerogel, with the mass fraction of the polyvinyl alcohol aqueous solution being 2% to prepare a sticky carbon aerogel;

[0059] 100g of carbon nanotubes were weighed and immersed in 1000g of polylysine solution for dispersion, and then the carbon nanotubes were separated. The porosity of the carbon nanotubes was 85-88%. Then, 10g of sticky carbon aerogel was evenly sprayed on the solution. The carbon aerogel had a porosity of 90-95%. After drying and dispersion, the finished carboxyl-modified carbon nanotubes were obtained. The particle size of the carboxyl-modified carbon nanotubes was 5μm.

[0060] Preparation Example 8: This preparation example differs from Preparation Example 7 in that:

[0061] 100g of carbon aerogel was evenly sprayed with 10g of polyvinyl alcohol aqueous solution, with a mass fraction of 2% of the polyvinyl alcohol aqueous solution, to prepare a sticky carbon aerogel;

[0062] 100g of carbon nanotubes were weighed and placed in 1000g of polylysine solution for immersion and dispersion, and then the carbon nanotubes were separated. 5g of sticky carbon aerogel was evenly sprayed on the solution, and then dried and dispersed to obtain finished carboxyl-modified carbon nanotubes. The particle size of the carboxyl-modified carbon nanotubes was 2μm.

[0063] Preparation Example 9: This preparation example differs from Preparation Example 7 in that:

[0064] 28 g of polyvinyl alcohol aqueous solution was evenly sprayed on the surface of 100 g of carbon aerogel, with the mass fraction of the polyvinyl alcohol aqueous solution being 2% to prepare a sticky carbon aerogel;

[0065] 100g of carbon nanotubes were weighed and placed in 1000g of polylysine solution for immersion and dispersion, and then the carbon nanotubes were separated. 20g of sticky carbon aerogel was evenly sprayed on the solution, and then dried and dispersed to obtain finished carboxyl-modified carbon nanotubes. The particle size of the carboxyl-modified carbon nanotubes was 10μm.

[0066] Example

[0067] Example 1: A method for treating nicotine pesticides in water:

[0068] S1. Add the polydopamine-modified macroporous resin prepared in Preparation Example 4 to water, wherein the polydopamine-modified macroporous resin accounts for 1% of the total amount of water, stir at 850 rpm for 36 hours, perform dispersion adsorption treatment, and then freeze at -30°C for 36 hours to obtain preliminary purified water;

[0069] S2. Thaw the preliminary purified water and restore it to room temperature, then heat it to 40°C, add the carboxyl-modified carbon nanotubes prepared in Preparation Example 7, and add the carboxyl-modified carbon nanotubes, where the carboxyl-modified carbon nanotubes account for 0.5% of the total amount of the preliminary purified water. First, stir at a speed of 850 r / min for 60 min, then stir at a speed of 200 r / min for 18 h, and finally let it stand for 4 h for dispersion adsorption treatment, solid-liquid separation, and take the filtrate to obtain purified water.

[0070] Example 2: A method for treating nicotine pesticides in water:

[0071] S1. Adding the polydopamine-modified macroporous resin prepared in Preparation Example 5 to water, wherein the polydopamine-modified macroporous resin accounts for 5% of the total amount of water, stirring at 500 rpm for 48 hours, performing a dispersion adsorption treatment, and then freezing at -20°C for 48 hours to obtain preliminary purified water;

[0072] S2. Thaw the preliminary purified water and restore it to room temperature, then heat it to 35°C, add the carboxyl-modified carbon nanotubes prepared in Preparation Example 8, and the carboxyl-modified carbon nanotubes account for 2% of the total amount of the preliminary purified water. First, stir at a speed of 500 r / min for 90 minutes, then stir at a speed of 120 r / min for 24 hours, and finally let it stand for 2 hours for dispersion adsorption treatment, solid-liquid separation, and take the filtrate to obtain purified water.

[0073] Example 3: A method for treating nicotine pesticides in water:

[0074] S1. Adding the polydopamine-modified macroporous resin prepared in Preparation Example 6 to water, wherein the polydopamine-modified macroporous resin accounts for 5% of the total amount of water, stirring at 1000 rpm for 24 hours, performing a dispersion adsorption treatment, and then freezing and crystallizing at -40°C for 24 hours to obtain preliminary purified water;

[0075] S2. Thaw the preliminary purified water and restore it to room temperature, then heat it to 45°C, add the carboxyl-modified carbon nanotubes prepared in Preparation Example 9, and the carboxyl-modified carbon nanotubes account for 2% of the total amount of the preliminary purified water. First, stir at a speed of 1000 r / min for 30 minutes, then stir at a speed of 250 r / min for 12 hours, and finally let it stand for 6 hours to perform dispersion adsorption treatment, solid-liquid separation, and take the filtrate to obtain purified water.

[0076] Example 4: This example differs from Example 1 in that:

[0077] The polydopamine solution in the polydopamine-modified macroporous resin was not added with carboxymethyl chitosan aqueous solution.

[0078] Example 5: This example differs from Example 1 in that:

[0079] During the preparation of carboxyl-modified carbon nanotubes, the polylysine solution was replaced with acetic acid of equal mass.

[0080] Example 6: This example differs from Example 1 in that:

[0081] During the preparation of carboxyl-modified carbon nanotubes, no sticky carbon aerogel was added.

[0082] Example 7: This example differs from Example 1 in that:

[0083] During the preparation of carboxyl-modified carbon nanotubes, the polyvinyl alcohol aqueous solution in the sticky carbon aerogel is replaced by an ethyl cellulose solution of equal mass, wherein the ethyl cellulose solution is an ethyl cellulose ethanol solution with a mass fraction of 1%.

[0084] Example 8: This example differs from Example 1 in that:

[0085] The stirring speed of the dispersion adsorption treatment in S2 was 200 r / min, and the stirring time was 19 h.

[0086] Comparative Example

[0087] Comparative Example 1: The difference between this comparative example and Example 1 is that:

[0088] In S1, the polydopamine-modified macroporous resin was replaced by macroporous resin of equal mass, and in S2, the carboxyl-modified carbon nanotubes were replaced by carbon nanotubes of equal mass.

[0089] Comparative Example 2: This comparative example differs from Example 1 in that:

[0090] No polydopamine-modified macroporous resin was added to S1.

[0091] Comparative Example 3: This comparative example differs from Example 1 in that:

[0092] No carboxyl-modified carbon nanotubes were added to S2.

[0093] Comparative Example 4: This comparative example differs from Example 1 in that:

[0094] S1 was not frozen.

[0095] Performance testing

[0096] 1. Adsorption test

[0097] The treatment methods of Examples 1-8 and Comparative Examples 1-4 were used to remove neonicotinoid pesticides (NNIs) in water. Neonicotinoid substances included imidacloprid (Imi), acetamiprid (Ace), clothianidin (clo), and thiamethoxam (Thim) (all with a purity greater than 95%). The content of neonicotinoid pesticides in water was 1 mg·L -1 Finally, the adsorption removal rate was recorded using Shimadzu LC-20AT high performance liquid chromatography.

[0098] Wherein: the mobile phase of imidacloprid (Imi) is acetonitrile / water = 60 / 40, with a wavelength of 270nm; the mobile phase of acetamiprid (Ace) is acetonitrile / water = 50 / 50, with a wavelength of 250nm; the mobile phase of clothianidin (clo) is acetonitrile / water = 60 / 40, with a wavelength of 250nm; the mobile phase of thiamethoxam (Thim) is acetonitrile / water = 40 / 60, with a wavelength of 255nm;

[0099]

[0100] Table 1 Performance test table

[0101]

[0102] It can be seen from Examples 1-3 and Table 1 that the treatment method of the present application has a high removal rate for nicotine pesticides, which proves that the adsorption effect is good and the nicotine pesticides remaining in the water are less.

[0103] Combining Example 1 and Examples 4-8 with Table 1, it can be seen that the polydopamine solution in the polydopamine-modified macroporous resin in Example 4 does not contain a carboxymethyl chitosan aqueous solution. Compared with Example 1, the adsorption removal rate of Example 4 is lower than that of Example 1. This indicates that the polydopamine aqueous solution and the carboxymethyl chitosan aqueous solution are combined, and the amino groups in polydopamine cooperate with the carboxyl groups and amino groups in carboxymethyl chitosan to form a network structure on the surface of the macroporous resin, thereby increasing the specific surface area of the macroporous resin and improving the adsorption efficiency and adsorption amount of the macroporous resin for nicotinic pesticides. Moreover, the presence of groups such as amino groups and carboxyl groups can further improve the adsorption amount of nicotinic pesticides by the macroporous resin.

[0104] In the preparation process of carboxyl-modified carbon nanotubes in Example 5, acetic acid of equal mass was used to replace the polylysine solution. Compared with Example 1, the adsorption removal rate of Example 5 was lower than that of Example 1. This shows that although acetic acid also has carboxyl groups, polylysine also contains some amino groups. The carboxyl groups and amino groups in polylysine are convenient for reacting simultaneously with the amino groups, carboxyl groups and hydroxyl groups on the surface of the polydopamine-modified macroporous resin, thereby improving the binding effect and the porosity, thereby improving the adsorption effect and reducing the content of nicotine pesticides in water.

[0105] During the preparation of carboxyl-modified carbon nanotubes in Example 6, no sticky carbon aerogel was added. Compared with Example 1, the adsorption removal rate of Example 6 was lower than that of Example 1, indicating that carbon aerogel has a higher porosity and better adsorption effect. When combined with carbon nanotubes, it can further improve the adsorption effect of carboxyl-modified aerogel and reduce nicotine pesticides in water.

[0106] In Example 7, during the preparation of carboxyl-modified carbon nanotubes, an equal mass of ethyl cellulose solution was used to replace the polyvinyl alcohol aqueous solution in the sticky carbon aerogel. Compared with Example 1, the adsorption removal rate of Example 7 was lower than that of Example 1. This indicates that the polyvinyl alcohol aqueous solution can interact with raw materials such as polylysine and polydopamine to form a network structure, thereby facilitating the entry of nicotine pesticides and water, thereby ensuring the adsorption of nicotine pesticides by the carboxyl-modified carbon nanotubes. Although ethyl cellulose can also bond the carbon aerogel to the surface of the carbon nanotubes, ethyl cellulose cannot interact with raw materials such as polylysine and polydopamine, which easily affects the porosity and thus the adsorption effect of nicotine pesticides in water.

[0107] The stirring speed of the dispersed adsorption treatment in Example 8S2 is 200r / min, and the stirring time is 19h. Compared with Example 1, the adsorption removal rate of Example 8 is less than that of Example 1; it indicates that high-speed stirring is first performed to uniformly disperse the carboxyl-modified carbon nanotubes and complete the adsorption, and then low-speed stirring is performed to facilitate the combination and sedimentation of the carboxyl-modified carbon nanotubes with the polydopamine-modified macroporous resin, and finally standing to facilitate layered filtration to obtain purified water. Combining Example 1 and Comparative Examples 1-4 with Table 1, it can be seen that in Comparative Example 1, the polydopamine-modified macroporous resin is replaced with the macroporous resin of equal mass, and the carboxyl-modified carbon nanotubes are replaced with the carbon nanotubes of equal mass, polydopamine-modified macroporous resin is not added in Comparative Example 2, and carboxyl-modified carbon nanotubes are not added in Comparative Example 3. Compared with Example 1, the adsorption removal rates of Comparative Examples 1, 2, and 3 are lower than those of Example 1; this indicates that the polydopamine-modified macroporous resin, freezing treatment, thawing, and carboxyl-modified carbon nanotubes are combined, and the polydopamine-modified macroporous resin first adsorbs nicotine pesticides, and then the freezing treatment combined with thawing promotes the polydopamine-modified macroporous resin to further adsorb nicotine pesticides while facilitating adhesion with the carboxyl-modified carbon nanotubes, forming a structure in which the carboxyl-modified carbon nanotubes are attached to the surface of the polydopamine-modified macroporous resin. The adsorption effect of the carboxyl-modified carbon nanotubes on nicotine pesticides is utilized to further reduce the content of nicotine pesticides in water, and the adhesion between the large particles facilitates filtration, thereby obtaining purified water, and the content of nicotine pesticides in the purified water is low.

[0108] Comparative Example 4 was not subjected to freezing treatment. Compared with Example 1, the adsorption removal rate of Comparative Example 4 was lower than that of Example 1, indicating that freezing treatment can minimize the pore blockage of the macroporous resin after adsorption of nicotine pesticides, thereby affecting the subsequent adsorption and bonding effects.

[0109] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for treating nicotine pesticides in water, characterized in that: The steps include: S1. Adding polydopamine-modified macroporous resin to water, and performing dispersion adsorption treatment and freezing treatment to obtain preliminary purified water; S2, adding carboxyl-modified carbon nanotubes to the initially purified water after thawing, and then subjecting it to dispersion and adsorption treatment, taking the liquid to obtain purified water; Carboxyl-modified carbon nanotubes are prepared by the following method: Weigh carbon nanotubes and place them in a polylysine solution for immersion and dispersion. Then take out the carbon nanotubes and evenly spray sticky carbon aerogel on the surface of the carbon nanotubes. The mass ratio of carbon nanotubes to sticky carbon aerogel is 1:0.05-0.

2. After drying and dispersion, the finished carboxyl-modified carbon nanotubes are obtained.

2. The method for treating nicotine pesticides in water according to claim 1, wherein: The polydopamine-modified macroporous resin is prepared by soaking the macroporous resin in a polydopamine solution.

3. The method for treating nicotine pesticides in water according to claim 2, characterized in that: The polydopamine solution consists of a polydopamine aqueous solution and a carboxymethyl chitosan aqueous solution in a mass ratio of 1:0.1-0.

5.

4. The method for treating nicotine pesticides in water according to claim 1, wherein: The viscous carbon aerogel consists of carbon aerogel and polyvinyl alcohol aqueous solution in a mass ratio of 1:0.1-0.

28.

5. The method for treating nicotine pesticides in water according to claim 1, characterized in that: The particle size of the polydopamine-modified macroporous resin is 100-250 μm, and the particle size of the carboxyl-modified carbon nanotube is 2-10 μm.

6. The method for treating nicotine pesticides in water according to claim 1, characterized in that: The freezing treatment temperature is -40 to -20°C, and the freezing time is 24 to 48 hours.

7. The method for treating nicotine pesticides in water according to claim 1, characterized in that: After thawing, the temperature is raised to 35-45° C., and then carboxyl-modified carbon nanotubes are added.

8. The method for treating nicotine pesticides in water according to claim 1, characterized in that: The dispersion adsorption treatment in S1 is carried out by stirring at 500-1000 r / min for 24-48 hours.

9. The method for treating nicotine pesticides in water according to claim 1, characterized in that: The dispersion adsorption treatment in S2 is firstly stirred at a speed of 500-1000 r / min for 30-90 min, then stirred at a speed of 120-250 r / min for 12-24 h, and finally allowed to stand for 2-6 h.

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