A persimmon tannin modified melamine formaldehyde porous polymer and a preparation method and application thereof

Abstract

The present application provides a persimmon tannin modified melamine formaldehyde porous polymer and a preparation method and application thereof, and belongs to the technical field of adsorbing materials for treating pesticide-containing wastewater. The preparation method provided by the present application is to modify persimmon tannin and melamine formaldehyde porous polymer by stirring and adsorbing reaction in a solvent, collect the solid product after the reaction is completed, and wash and dry to obtain the product. The prepared persimmon tannin modified melamine formaldehyde porous polymer has excellent adsorption effect on 2,4-D, flurichloride, fluoroglycofen, fomesafen, naphthalene acetic acid and indole acetic acid and other pesticides.

Description

Technical Field

[0001] This invention relates to the field of adsorption materials for treating pesticide-containing wastewater, and particularly to a persimmon tannin-modified melamine porous polymer, its preparation method, and its application. Background Technology

[0002] my country is a major agricultural producer, and agricultural development directly impacts overall social and economic benefits. Pesticides, as a crucial component of agricultural production, play a positive role in the healthy growth of crops. In recent years, with the continuous development of science and technology, the scale of agricultural production has gradually expanded, leading to a corresponding increase in pesticide use. While improving agricultural production efficiency, pesticide residues and pollution in the environment have also significantly impacted the rural ecological environment and human health.

[0003] Pesticide pollution of water bodies mainly originates from the following pathways: (1) direct spraying or application of granules into water to control aquatic pests; (2) pesticides falling into irrigation water from farmland spraying; (3) pesticides in the soil flowing into rivers with rainwater; (4) wastewater discharge from pesticide factories; (5) washing pesticide application tools along riverbanks; and (6) pesticides falling directly into rivers and lakes from the atmosphere or along with rainwater and dust. Generally speaking, a small amount of pesticide pollution in water bodies comes from soil erosion, while a large amount of pollution is caused by wastewater discharged from pesticide factories and by the application of pesticides and the washing of pesticide application tools. Therefore, targeted and sustainable management of pesticide pollution is of great practical significance for improving human health and ecological benefits.

[0004] Adsorption is a common method for pollutant treatment. Among industrial adsorption materials, activated carbon is the most common, primarily existing in granular and powdered form. Activated carbon can be made from plant and animal matter, coal, petroleum, waste paper pulp, waste synthetic resins, and other organic residues. The process involves crushing, adding binders to form a mold, heating, dehydration, carbonization, and activation. Activated carbon possesses a huge specific surface area and highly developed micropores, with a specific surface area typically ranging from 500 to 1700 m². 2 With a micropore volume of approximately 0.15-0.9 mL / g and a surface area accounting for over 95% of the total surface area, activated carbon is a good adsorbent. However, its regeneration is difficult, and its adsorption effect on some pesticides is poor, limiting its use. Therefore, the development and manufacture of new alternatives is of great significance.

[0005] Research on pesticide pollutant adsorption is developing rapidly, but due to the large variety of pesticides, many pesticide pollutants still lack effective adsorption solutions. Therefore, developing new adsorption materials for pesticides is of practical purpose and market demand. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a persimmon tannin-modified melamine-formaldehyde porous polymer, its preparation method and application. The tannin-modified melamine-formaldehyde porous polymer provided by this invention has excellent adsorption effects on pesticides such as 2,4-D, ethoxysulfuron, trifluralin, flusulfanilamide, naphthaleneacetic acid and indoleacetic acid.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing persimmon tannin-modified melamine-formaldehyde porous polymer, wherein persimmon tannin and melamine-formaldehyde porous polymer are subjected to a stirring adsorption reaction in a solvent for modification, and after the reaction is completed, the solid product is collected by filtration, washed, and dried to obtain the final product.

[0008] In some embodiments, the mass ratio of persimmon tannin to melamine-formaldehyde porous polymer is 1:(1-10).

[0009] In other embodiments, the mass ratio of persimmon tannin to melamine-formaldehyde porous polymer is 1:(6-7), preferably 1:6.

[0010] In some embodiments, the solvent is water, methanol, ethanol, propanol, isopropanol, or butanol.

[0011] In other embodiments, the solvent is water or methanol, preferably water.

[0012] In some embodiments, the stirring reaction temperature is 0±3℃-80±3℃; the stirring reaction time is 1-10h.

[0013] In other embodiments, the stirring reaction temperature is 50±3℃-60±3℃; the stirring reaction time is 3h.

[0014] In other embodiments, the stirring reaction temperature is 60±3℃; the stirring reaction time is 3h.

[0015] The present invention also provides a persimmon tannin-modified melamine-formaldehyde porous polymer prepared by the preparation method described in the above technical solution.

[0016] This invention also provides the application of the persimmon tannin-modified melamine-formaldehyde porous polymer described in the above technical solution in the adsorption and treatment of specific pesticide pollutants, wherein the pesticide pollutants include 2,4-D, ethoxysulfuron, trifluralin, flusulfanilamide, naphthaleneacetic acid, and indoleacetic acid.

[0017] Beneficial technical effects:

[0018] 1. This invention uses persimmon tannin to modify melamine-formaldehyde porous polymer. The modified melamine-formaldehyde porous polymer has a strong adsorption effect on pesticides such as 2,4-D, ethoxysulfuron, trifluralin, flusulfanilamide, naphthaleneacetic acid, and indoleacetic acid, which is beneficial for the treatment of pesticide wastewater.

[0019] 2. The preparation method provided by this invention is simple and does not require harsh conditions such as high temperature and high pressure. It can obtain excellent specific pesticide adsorption performance by simply modifying the porous polymer of melamine-formaldehyde with persimmon tannin, which has strong practicality. Attached Figure Description

[0020] Figure 1 Infrared spectra of melamine-paraformaldehyde polymer and persimmon tannin-modified melamine-formaldehyde porous polymer material before and after adsorption of 2,4-drop;

[0021] Figure 2 (a) is a SEM image of melamine-paraformaldehyde polymer; Figure 2 (b) is a SEM image of persimmon tannin-modified melamine-formaldehyde porous polymer; Figure 2 (c) is a SEM image of 2,4-drop adsorption of persimmon tannin-modified melamine-formaldehyde porous polymer. Figure 2 (d) is a diagram showing the Cl element distribution of melamine-paraformaldehyde polymer; Figure 2 (e) is a diagram showing the Cl element distribution of the persimmon tannin-modified melamine-formaldehyde porous polymer; Figure 2 (f) is the Cl element distribution diagram after 2,4-drop adsorption by the persimmon tannin-modified melamine-formaldehyde porous polymer. Figure 2 (g) is the energy spectrum of melamine-paraformaldehyde polymer; Figure 2 (h) is the energy spectrum of persimmon tannin-modified melamine-formaldehyde porous polymer; Figure 2 (i) is the energy spectrum of 2,4-drop adsorption of persimmon tannin-modified melamine-formaldehyde porous polymer. Detailed Implementation

[0022] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0023] Reference for the preparation of melamine-formaldehyde porous polymer: W. Lu, PS Julian, D. Yuan, R. Krishna, Z. Wei, HC Zhou, Angew. Chem., Int. Ed. 2012, 51, 7480.

[0024] References for the preparation of persimmon tannin: Extraction and purification of persimmon tannin and its application in the treatment of tetracycline-polluted water, Qian Xi, Master's thesis, Guilin University of Electronic Technology.

[0025] Examples 1-6

[0026] 1.0 g of persimmon tannin, 1.0 g of melamine-formaldehyde porous polymer, and 30 ml of solvent were added to a reaction flask and stirred at 60 °C for 3 hours. The mixture was then cooled and stirred at room temperature (20 °C) for 1 hour. The resulting tannin-modified porous polymer was filtered, washed with 30 mL × 3 mL of the reaction solvent, and vacuum dried at 50 °C to obtain the persimmon tannin-modified melamine-formaldehyde porous polymer sample. The choice of solvent, the specific surface area of ​​the modified melamine-formaldehyde porous polymer, and the adsorption capacity of persimmon tannin are shown in Table 1.

[0027] Table 1

[0028]

[0029] Examples 7-15

[0030] Same as Example 1, except that the mass ratio of persimmon tannin to melamine-formaldehyde porous polymer was changed. The selection of the mass ratio of persimmon tannin to melamine-formaldehyde porous polymer, as well as the specific surface area of ​​the modified melamine-formaldehyde porous polymer and the adsorption capacity of persimmon tannin, are shown in Table 2.

[0031] Table 2

[0032]

[0033]

[0034] As shown in Table 2, with the increase of the adsorption ratio of persimmon tannin, the specific surface area of ​​the modified melamine-formaldehyde porous polymer gradually decreases. It is necessary to balance the specific surface area of ​​the modified melamine-formaldehyde porous polymer and the adsorption amount of persimmon tannin so that the persimmon tannin-modified melamine-formaldehyde porous polymer can have the best pesticide adsorption performance.

[0035] Examples 16-25

[0036] Same as Example 1, except that the modification reaction temperature is adjusted. When the reaction temperature is 0-20°C, the reaction time is 4 hours to complete the reaction. When the reaction temperature is greater than 20°C, the mixture is stirred at that temperature for 3 hours, then cooled down and stirred at room temperature (20°C) for 1 hour.

[0037] Table 3 shows the specific surface area and adsorption capacity of persimmon tannins of the modified melamine-formaldehyde porous polymer at different modification reaction temperatures.

[0038] Table 3

[0039]

[0040]

[0041] As shown in Table 3, the adsorption capacity of persimmon tannin in the modified melamine-formaldehyde porous polymer increases with increasing temperature, while the specific surface area decreases with increasing adsorption capacity. After reaching 60℃, the adsorption capacity begins to reach equilibrium and decreases slightly. Therefore, the optimal reaction temperature is 60℃.

[0042] Examples 26-30

[0043] Same as Example 1, except that the reaction time was adjusted. The reaction time, specific surface area of ​​the modified melamine-formaldehyde porous polymer, and adsorption capacity of persimmon tannin are shown in Table 4.

[0044] Table 4

[0045]

[0046] As shown in Table 4, the adsorption capacity of persimmon tannin in the modified melamine-formaldehyde porous polymer increases with time, while the specific surface area decreases with increasing adsorption capacity. After 3 hours, the adsorption capacity begins to reach equilibrium. Therefore, the optimal reaction time is 3 hours.

[0047] Experimental Example 1

[0048] The pesticides used were numbered 2,4-D (No. 1), ethoxysulfuron (No. 2), trifluralin (No. 3), flusulfanilamide (No. 4), naphthaleneacetic acid (No. 5), and indoleacetic acid (No. 6); the activated carbon was purchased from Beijing Innochem Technology Co., Ltd., model Innochem A60101, with a specific surface area of ​​1170 m². 2 / g.

[0049] The adsorption of pesticides was measured using the persimmon tannin-modified melamine-formaldehyde porous polymers from Examples 1 and 7-15. The test results are shown in Table 5.

[0050] Table 5

[0051]

[0052] Observing the adsorption patterns in Table 5, the results show that the optimal adsorption effect is achieved when the ratio of persimmon tannin to melamine-formaldehyde porous material is 1:(6-7). This result indicates that the modification of melamine-formaldehyde porous material with persimmon tannin has a certain range; without persimmon tannin or with a small amount of persimmon tannin, the modification performance is insufficient and the adsorption effect is weak; when more persimmon tannin is adsorbed, the specific surface area may decrease, which also affects the adsorption effect; therefore, the optimal adsorption effect can only be achieved when the ratio of persimmon tannin to melamine-formaldehyde porous material is 1:(6-7).

[0053] Experimental Example 2: Screening of Pesticide Adsorption Species

[0054] Evaluation criteria: pesticides with an adsorption capacity higher than 150 mg / g are highly adsorbent pesticides, those with an adsorption capacity of 50-150 mg / g are moderately adsorbent pesticides, and those with an adsorption capacity lower than 50 mg / g are pesticides with poor adsorption effect.

[0055] Tannins and tea tannins were purchased from Beijing Inokai Technology Co., Ltd.

[0056] The tannin-modified materials were prepared using the same method as in Example 11, with a raw material ratio of 1:6, i.e., tannin: melamine-formaldehyde porous material = 1:6. This yielded persimmon tannin-modified melamine-formaldehyde porous polymer, tannic acid tannin-modified melamine-formaldehyde porous polymer, and tea tannin-modified melamine-formaldehyde porous polymer. The adsorption performance of the three tannin-modified melamine-formaldehyde porous polymers, the unmodified melamine porous polymer, and the control activated carbon for different pesticides was tested. The test results are shown in Table 6.

[0057] Table 6

[0058]

[0059]

[0060] As can be seen from the pesticide adsorption test, the persimmon tannin-modified melamine-paraformaldehyde porous material has high adsorption performance for the most types of pesticides. Its performance is outstanding compared with tannic acid tannin and tea tannin, and it also greatly exceeds that of unmodified melamine-paraformaldehyde porous material and activated carbon. This shows that persimmon tannin plays a prominent role in the modification of this type of material and is difficult to replace.

[0061] In summary, the persimmon tannin-modified melamine-formaldehyde porous polymer provided by this invention exhibits excellent adsorption and removal performance for pesticides such as 2,4-D, ethoxysulfuron, trifluralin, flusulfanilamide, naphthaleneacetic acid, and indoleacetic acid, and can be applied to the adsorption and removal of pesticide pollutants in water bodies.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a persimmon tannin-modified melamine-formaldehyde porous polymer, characterized in that, The persimmon tannin and melamine-formaldehyde porous polymer were modified by stirring and adsorption reaction in a solvent. After the reaction was completed, the solid product was collected by filtration, washed and dried to obtain the final product. The mass ratio of persimmon tannin to melamine-formaldehyde porous polymer is 1:(1-10); The solvent is water, methanol, ethanol, propanol, isopropanol, or butanol; The stirring adsorption reaction temperature is 0±3℃-80±3℃; the stirring adsorption reaction time is 1-10h.

2. The preparation method according to claim 1, characterized in that, The mass ratio of persimmon tannin to melamine-formaldehyde porous polymer is 1:(6-7).

3. The preparation method according to claim 1, characterized in that, The solvent is water or methanol.

4. The preparation method according to claim 1, characterized in that, The stirring adsorption reaction temperature is 50±3℃-60±3℃; the stirring adsorption reaction time is 2-5h.

5. The preparation method according to claim 1, characterized in that, The stirring adsorption reaction temperature is 60±3℃; the stirring adsorption reaction time is 3h.

6. The persimmon tannin-modified melamine-formaldehyde porous polymer prepared by the preparation method according to any one of claims 1-5.

7. The application of the persimmon tannin-modified melamine-formaldehyde porous polymer of claim 6 in the adsorption and treatment of pesticide pollutants; wherein the pesticide pollutants include 2,4-D, ethoxysulfuron, trifluralin, flusulfanilamide, naphthaleneacetic acid, and indoleacetic acid.

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