A carboxymethyl cellulose-based imidazole zwitterionic polymer and its preparation method and application

Abstract

The invention relates to the technical field of ionic polymers and the technical field of their application in sewage treatment, and discloses a carboxymethyl cellulose-based imidazole zwitterionic polymer and a preparation method and application thereof. The invention uses sodium carboxymethyl cellulose as a raw material, takes it as a substrate, grafts 1-(3-aminopropyl) imidazole on a carboxyl group, and finally attacks the imidazole group with diphenylbenzyl chloride to form a large imidazole cation. The appearance of the large cation makes the sodium carboxymethyl cellulose, which is an anionic polymer, amphoteric, so that it can have a good adsorption effect on pollutants in water. The synthesized carboxymethyl cellulose-based imidazole zwitterionic polymer has a good adsorption effect on both anionic pollutants and cationic pollutants in water, and has a good inhibitory effect on the growth of bacteria. It has good application prospects in the biological filter in the secondary wastewater treatment unit.

Description

Technical Field

[0001] The invention belongs to the technical field of ionic polymers and sewage treatment, and specifically relates to a carboxymethyl cellulose-based imidazole zwitterionic polymer and a preparation method and application thereof. Background Art

[0002] Modern industry consumes a huge amount of water, which makes the treatment of industrial wastewater a key component of sustainable water reuse. At the same time, the pollution of these waters poses a serious challenge to sustainable living. Among the countless pollutants released by industries such as textiles, pharmaceuticals, food, cosmetics and paints, synthetic dyes are an important component. These dyes are often toxic and have potential carcinogenic effects. Globally, 10% to 15% of industrially produced dyes are released into the environment. Wastewater containing dyes will have serious excessive bacterial flora, and these pollutants are very harmful to the ecological environment. For example, methylene blue is a thiazine cationic dye that can cause harmful effects on human health when present in water, such as nausea, diarrhea, difficulty breathing, and eye burns when contacted or ingested. Congo red is an azo anionic dye that, when decomposed under special conditions, produces a variety of carcinogenic aromatic amines, which can cause changes in DNA structure through activation in the human body, thereby causing cell pathology and inducing cancer.

[0003] Currently, there are various methods for wastewater treatment, including physical methods such as screening, flotation and centrifugal separation technology; chemical methods such as coagulation, flocculation, redox reaction and chemical precipitation; and biological methods such as activated sludge method, biofilm technology, and the use of microorganisms in water to degrade harmful substances. However, these methods generally have limitations such as cumbersome operation and long cycle. In contrast, adsorption method has been widely favored by people due to its low cost, simple operation and rapid treatment effect. Summary of the invention

[0004] The invention provides a carboxymethyl cellulose-based imidazole zwitterionic polymer and a preparation method and application thereof. The carboxymethyl cellulose-based imidazole zwitterionic polymer is green, environmentally friendly, low-priced, and has excellent antibacterial properties. It can be applied to filter materials in biological filters in wastewater secondary treatment units to quickly treat pollution caused by methylene blue cationic dyes and Congo red anionic dyes.

[0005] The technical solution of the present invention is as follows:

[0006] A method for preparing a carboxymethyl cellulose-based imidazole zwitterionic polymer, characterized in that it comprises the following steps:

[0007] Step 1, dissolving sodium carboxymethyl cellulose in a mixed solvent of DMF and water to form a mixed solution, wherein the mass concentration of sodium carboxymethyl cellulose is 27 g / L-34 g / L, and the volume ratio of DMF to water is 0.5-1:1-2;

[0008] Step 2, adding a DMF solution of N-hydroxysuccinimide to the mixed solution in step 1 to react, wherein the mass concentration of N-hydroxysuccinimide in the DMF solution is 80 g / L-120 g / L;

[0009] Step 3, adding a DMF solution of 1-(3-aminopropyl)-imidazole to the solution after the reaction in step 2 to carry out a reaction, wherein the mass concentration of 1-(3-aminopropyl)-imidazole in the DMF solution is 100 g / L-140 g / L;

[0010] In the steps 1, 2 and 3, the mass ratio of sodium carboxymethyl cellulose, N-hydroxysuccinimide and 1-(3-aminopropyl)-imidazole is 8-10:4-6:5-7;

[0011] Step 4, after the reaction in step 3, adding anhydrous ethanol to precipitate the sodium carboxymethyl cellulose grafted 1-(3-aminopropyl)-imidazole, then washing with a DMF solution, and vacuum drying after washing; the volume ratio of the added anhydrous ethanol to the volume of the solution after the reaction in step 3 is at least 2:1;

[0012] Step 5, dissolving the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole after vacuum drying in step 4 in a dimethyl sulfoxide solution, wherein the mass concentration of the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole is 40 g / L-50 g / L; then dropping a DMSO solution of biphenyl dichlorobenzyl to react by stirring, wherein the mass concentration of biphenyl dichlorobenzyl in the DMSO solution is 80 g / L-120 g / L; after the reaction, washing and drying are performed to obtain the final product;

[0013] In the step 5, the mass ratio of the product of sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole to biphenyl dichlorobenzyl is 2-3:1-2.

[0014] In the step 2, the reaction time of sodium carboxymethyl cellulose and N-hydroxysuccinimide is 10h-12h at room temperature.

[0015] In step 4, the temperature in the vacuum drying oven is controlled to be 40-45° C. during vacuum drying, and the drying time is 20 h to 24 h.

[0016] In step 5, the DMSO solution of biphenyl dichloride is added dropwise and stirred for reaction for 12-16 hours, wherein the reaction is stirred at room temperature for 8-10 hours, and then the temperature is raised to 40° C.-45° C. and stirred for reaction for 4-6 hours.

[0017] In step 5, the temperature in the vacuum drying oven is controlled to be 55° C.-60° C. during drying, and the drying time is 20 h-24 h.

[0018] The carboxymethyl cellulose-based imidazole zwitterionic polymer prepared by the above scheme can quickly adsorb methylene blue cationic dye and Congo red anionic dye, and has certain antibacterial properties and is environmentally friendly.

[0019] The present invention also discloses an application of a carboxymethyl cellulose-based imidazole zwitterionic polymer in sewage treatment, wherein the carboxymethyl cellulose-based imidazole zwitterionic polymer can repair sewage containing methylene blue or Congo red. The concentration of methylene blue in the sewage is 20 mg / L-25 mg / L, and the added concentration of the carboxymethyl cellulose-based imidazole zwitterionic polymer is 0.5 g / L-10 g / L. The concentration of Congo red in the sewage is 20 mg / L-25 mg / L; the added concentration of the carboxymethyl cellulose-based imidazole zwitterionic polymer ranges from 1 g / L to 15 g / L.

[0020] The present invention also discloses an application of a carboxymethyl cellulose-based imidazole zwitterionic polymer in an antibacterial experiment. The carboxymethyl cellulose-based imidazole zwitterionic polymer is pressed into a thin sheet with a diameter of 1 cm-1.5 cm by a mold, and then placed in a culture dish evenly coated with a bacterial solution, and then cultured in a constant temperature incubator at 35° C.-40° C. for 6-8 days; the bacterial solution contains at least one of Aspergillus niger or Phanerochaete chrysosporium.

[0021] Beneficial effects of the present invention:

[0022] 1. The present invention uses sodium carboxymethyl cellulose as a raw material, which is a widely used, cheap industrial product derived from cellulose, easily degradable and environmentally friendly. Using it as a substrate, the carboxymethyl cellulose-based imidazole zwitterionic polymer is synthesized, which not only inherits the above advantages of the raw material sodium carboxymethyl cellulose, but also has zwitterionic groups, so that it can have a good adsorption effect on anionic pollutants and cationic pollutants in water.

[0023] 2. The carboxymethyl cellulose-based imidazole zwitterionic polymer prepared by the present invention is also a kind of quaternary ammonium salt. The quaternary ammonium salt has a permanent and pH-independent positive charge, which can interact with the phospholipid bilayer of the bacterial cell membrane and destroy its integrity, leading to leakage of intercellular components and cell death, and has a good inhibitory effect on bacterial growth.

[0024] 3. The carboxymethyl cellulose-based imidazole zwitterionic polymer prepared by the present invention has good application prospects in the biofilter in the secondary wastewater treatment unit.

[0025] 4. The present invention uses sodium carboxymethyl cellulose as a raw material, grafts 1-(3-aminopropyl) imidazole onto the carboxyl group, and finally uses biphenyl dichlorobenzyl to attack the imidazole group to form an imidazole macrocation. The appearance of the macrocation makes sodium carboxymethyl cellulose, which is an anionic polymer, amphoteric, so that it can have a good adsorption effect on pollutants in water. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the reaction equation for grafting imidazole onto carboxymethyl fiber of the present invention;

[0027] Figure 2 is the reaction formula of the carboxymethyl cellulose based imidazole zwitterionic polymer of the present invention;

[0028] Figure 3 The nuclear magnetic spectra of CMC, CMC-APIm and CMC-APIm-Cl of the present invention;

[0029] Figure 4 This is a scanning electron microscope image of CMC-APIm-Cl of the present invention;

[0030] Figure 5 This is a scanning electron microscope image of CMC-APIm-Cl after adsorption of Congo red in the present invention;

[0031] Figure 6 This is a scanning electron microscope image of CMC-APIm-Cl after adsorption of methylene blue according to the present invention;

[0032] Figure 7 It is the removal rate of methylene blue (MB) and Congo red (CR) corresponding to the input amount of CMC-APIm-Cl in the present invention;

[0033] Figure 8 The removal rates of methylene blue and Congo red of CMC-APIm-Cl under different pH conditions of the present invention;

[0034] Fig. 9 The removal rates of methylene blue and Congo red of CMC-APIm-Cl at different reaction times of the present invention;

[0035] Fig.10 The removal rates of methylene blue and Congo red of CMC-APIm-Cl under different temperature conditions of the present invention;

[0036] Fig.11 The antibacterial effect of the common sterile drug-sensitive paper sheet of the present invention;

[0037] Fig.12 The antibacterial effect of CMC-APIm-Cl of the present invention on Aspergillus niger;

[0038] Fig.13The results show the antibacterial effect of CMC-APIm-Cl of the present invention on Phanerochaete chrysosporium. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Example 1

[0040] Step 1: Dissolve sodium carboxymethyl cellulose (CMC) in a mixed solvent of DMF and water to form 300 mL of a mixed solution, wherein the mass concentration of sodium carboxymethyl cellulose is 30 g / L, and the volume ratio of DMF to water is 0.5:1.

[0041] Step 2: Add 50 mL of DMF solution of N-hydroxysuccinimide to the mixed solution in step 1 and react for 10 hours. The mass concentration of N-hydroxysuccinimide in the DMF solution is 100 g / L.

[0042] Step 3: Add 50 mL of 1-(3-aminopropyl)-imidazole DMF solution to the solution after the reaction in step 2 for reaction. The mass concentration of 1-(3-aminopropyl)-imidazole in the DMF solution is 120 g / L.

[0043] The mass ratio of the sodium carboxymethyl cellulose, N-hydroxysuccinimide and 1-(3-aminopropyl)-imidazole is 9:5:6.

[0044] Step 4: After the reaction in step 3, anhydrous ethanol is added to precipitate sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole, and then washed with a DMF solution, and then vacuum dried; during vacuum drying, the temperature in the vacuum drying oven is controlled to be 40° C., and the drying time is 20 hours. The product sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole, i.e., CMC-APIm, after washing and drying is a white flocculent. The volume ratio of the added anhydrous ethanol to the solution after the reaction in step 3 is 2:1.

[0045] Step 5, dissolving the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole after vacuum drying in step 4 in 200 mL of dimethyl sulfoxide solution, wherein the mass concentration of the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole is 40 g / L; then dropping 50 mL of a DMSO solution of biphenyl benzyl chloride and stirring for reaction, the stirring reaction time is 12 hours, wherein the stirring reaction is carried out at room temperature for 8 hours, and then the temperature is raised to 40° C. and stirred for reaction for 4 hours; the mass concentration of biphenyl benzyl chloride in the DMSO solution is 80 g / L; washing and drying after the reaction, during drying, the temperature in the vacuum drying oven is controlled to be 55° C., and the drying time is 20 hours; the final product, carboxymethyl cellulose-based imidazole zwitterionic polymer (i.e., CMC-APIm-Cl), is obtained, and the final product is a white powder.

[0046] The mass ratio of the product of sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole to biphenyl dichlorobenzyl is 2:1. Example 2

[0047] Step 1: Dissolve sodium carboxymethyl cellulose (CMC) in a mixed solvent of DMF and water to form 300 mL of a mixed solution, wherein the mass concentration of sodium carboxymethyl cellulose is 27 g / L, and the volume ratio of DMF to water is 0.7:2.

[0048] Step 2: Add 50 mL of DMF solution of N-hydroxysuccinimide to the mixed solution in step 1 and react for 12 hours. The mass concentration of N-hydroxysuccinimide in the DMF solution is 80 g / L.

[0049] Step 3: Add 50 mL of 1-(3-aminopropyl)-imidazole DMF solution to the solution after the reaction in step 2 for reaction. The mass concentration of 1-(3-aminopropyl)-imidazole in the DMF solution is 100 g / L.

[0050] The mass ratio of sodium carboxymethyl cellulose, N-hydroxysuccinimide and 1-(3-aminopropyl)-imidazole is 8:4:5.

[0051] Step 4. After the reaction in step 3, anhydrous ethanol is added to precipitate sodium carboxymethyl cellulose grafted 1-(3-aminopropyl)-imidazole, and then washed with a DMF solution, and vacuum dried after washing; during vacuum drying, the temperature in the vacuum drying oven is controlled to be 45° C., and the drying time is 24 hours. The product sodium carboxymethyl cellulose grafted 1-(3-aminopropyl)-imidazole (CMC-APIm) after washing and drying is a white flocculent, and the volume ratio of the added volume of the anhydrous ethanol to the solution after the reaction in step 3 is 2.2:1.

[0052] Step 5, dissolving the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole after vacuum drying in step 4 in 200 mL of dimethyl sulfoxide solution, wherein the mass concentration of the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole is 45 g / L; then adding 60 mL of the DMSO solution of biphenyl benzyl chloride and stirring for reaction, the stirring reaction time is 16 hours, wherein the stirring reaction is carried out at room temperature for 10 hours, and then the temperature is raised to 42° C. and stirred for reaction for 6 hours; the mass concentration of biphenyl benzyl chloride in the DMSO solution is 100 g / L, and the reaction is washed and dried after the reaction, and the temperature in the vacuum drying oven is controlled to be 60° C. during drying, and the drying time is 24 hours; the final product, carboxymethyl cellulose-based imidazole zwitterionic polymer (i.e., CMC-APIm-Cl), is obtained; the final product is a white powder.

[0053] The mass ratio of the product of sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole to biphenyl dichlorobenzyl is 3:2. Example 3

[0054] Step 1: Dissolve sodium carboxymethyl cellulose (CMC) in a mixed solvent of DMF and water to form 300 mL of a mixed solution, wherein the mass concentration of sodium carboxymethyl cellulose is 34 g / L, and the volume ratio of DMF to water is 1:1.

[0055] Step 2: Add 50 mL of DMF solution of N-hydroxysuccinimide to the mixed solution in step 1 and react for 11 hours. The mass concentration of N-hydroxysuccinimide in the DMF solution is 120 g / L.

[0056] Step 3: Add 50 mL of 1-(3-aminopropyl)-imidazole DMF solution to the solution after the reaction in step 2 for reaction. The mass concentration of 1-(3-aminopropyl)-imidazole in the DMF solution is 140 g / L.

[0057] The mass ratio of the sodium carboxymethyl cellulose, N-hydroxysuccinimide and 1-(3-aminopropyl)-imidazole is 10:6:7.

[0058] Step 4. After the reaction in step 3, anhydrous ethanol is added to precipitate sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole, and then washed with a DMF solution, and then vacuum dried; during vacuum drying, the temperature in the vacuum drying oven is controlled to be 43° C., and the drying time is 22 hours. The product after washing and drying is sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole, i.e., CMC-APIm, and the product is a white flocculent. The volume ratio of the added volume of the anhydrous ethanol to the volume of the solution after the reaction in step 3 is 2.5:1.

[0059] Step 5, dissolving the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole after vacuum drying in step 4 in 200 mL of dimethyl sulfoxide solution, wherein the mass concentration of the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole is 50 g / L; then adding 50 mL of a DMSO solution of biphenyl benzyl chloride and stirring for reaction, the stirring reaction time is 14 hours, wherein the stirring reaction is carried out at room temperature for 9 hours, and then the temperature is raised to 45° C. and stirred for reaction for 5 hours; the mass concentration of biphenyl benzyl chloride in the DMSO solution is 120 g / L, and the reaction is washed and dried after the reaction, and the temperature in the vacuum drying oven is controlled to be 58° C. during drying, and the drying time is 22 hours; the final product, carboxymethyl cellulose-based imidazole zwitterionic polymer (i.e., CMC-APIm-Cl), is obtained; the final product is a white powder.

[0060] The mass ratio of the product of sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole to biphenyl dichlorobenzyl is 5:3. Example 4

[0061] Prepare 20mg / L-25mg / L methylene blue solution and Congo red solution respectively, add carboxymethyl cellulose imidazole zwitterionic polymer (CMC-APIm-Cl) to methylene blue solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 0.5g / L-10g / L), and Congo red solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 1g / L-15g / L); the removal rate is measured at pH 7, reaction time 5min, and temperature 30℃, as shown in the following table:

[0062]

[0063] The removal rate data of methylene blue and Congo red by the carboxymethyl cellulose based imidazole zwitterionic polymer (CMC-APIm-Cl) obtained in the present invention are as follows: Figure 7 As shown. Figure 7 It can be seen that carboxymethyl cellulose based imidazole zwitterionic polymers have good removal effects on methylene blue and Congo red, with a methylene blue removal rate of more than 87.7% (carboxymethyl cellulose based imidazole zwitterionic polymer dosage 0.5g / L-10g / L). The Congo red removal rate can reach more than 72.9% (carboxymethyl cellulose based imidazole zwitterionic polymer dosage 1g / L-15g / L). Example 5

[0064] Prepare 25 mg / L methylene blue solution and Congo red solution respectively, add carboxymethyl cellulose imidazole zwitterionic polymer (CMC-APIm-Cl) to methylene blue solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 5.0 g / L) and Congo red solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 7.5 g / L), respectively; carry out removal experiments at different pH values ​​(4-10), reaction time 8 min, temperature 35°C, and determine the removal rate, as shown in the following table:

[0065]

[0066] The removal rate data of methylene blue and Congo red by the carboxymethyl cellulose based imidazole zwitterionic polymer (CMC-APIm-Cl) obtained in the present invention are as follows: Figure 8 As shown, from Figure 8 It can be seen that carboxymethyl cellulose-based imidazole zwitterionic polymers have good removal effects on methylene blue and Congo red, and the removal rates of carboxymethyl cellulose-based imidazole zwitterionic polymers on methylene blue and Congo red are almost unaffected by pH value. Example 6

[0067] Prepare 22 mg / L methylene blue solution and Congo red solution respectively, add carboxymethyl cellulose imidazole zwitterionic polymer (CMC-APIm-Cl) to methylene blue solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 6.0 g / L) and Congo red solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 9.0 g / L), respectively, and carry out removal experiments at different reaction times (1 min-7 min), pH value of 6, and temperature of 24 ° C to determine the removal rate, as shown in the following table:

[0068]

[0069] The removal rate data of methylene blue and Congo red by the carboxymethyl cellulose based imidazole zwitterionic polymer (CMC-APIm-Cl) obtained in the present invention are as follows: Fig. 9 As shown, from Fig. 9 It can be seen that carboxymethyl cellulose-based imidazole zwitterionic polymers have good removal effects on methylene blue and Congo red, with a methylene blue removal rate of more than 88% and a Congo red removal rate of more than 72%. Whether it is a cationic dye (methylene blue) or an anionic dye (Congo red), the carboxymethyl cellulose-based imidazole zwitterionic polymer has a very fast removal rate for them, and the adsorption is completed within about 5 minutes. Example 7

[0070] Prepare 22 mg / L methylene blue solution and Congo red solution respectively, add carboxymethyl cellulose imidazole zwitterionic polymer (CMC-APIm-Cl) to methylene blue solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 6.0 g / L) and Congo red solution (the concentration of carboxymethyl cellulose imidazole zwitterionic polymer after addition is 9.0 g / L); pH value is 5, reaction time is 5min, removal experiments are carried out at different temperatures (10℃-40℃), and the removal rates are shown in the following table:

[0071]

[0072] The removal rate data of methylene blue and Congo red by the carboxymethyl cellulose based imidazole zwitterionic polymer (CMC-APIm-Cl) obtained in the present invention are as follows: Fig.10 As shown. Fig.10 It can be seen that carboxymethyl cellulose based imidazole zwitterionic polymers have good removal effects on methylene blue and Congo red, with a methylene blue removal rate of more than 88% and a Congo red removal rate of more than 80%. Whether it is a cationic dye (methylene blue) or an anionic dye (Congo red), the removal rate of carboxymethyl cellulose based imidazole zwitterionic polymers is almost unaffected by temperature. Example 8

[0073] Aspergillus niger and Phanerochaete chrysosporium bacterial suspensions were prepared respectively and spread evenly on the surface of culture dishes. Carboxymethylcellulose-based imidazole zwitterionic polymer (CMC-APIm-Cl) was pressed into 1 g / cm thin slices with a diameter of 1 cm. The slices were then placed in the culture dishes evenly spread with the bacterial suspensions and cultured in a constant temperature incubator at 40°C for 8 days to observe the growth of the bacteria.

[0074] like Figure 11-13 As shown, Fig.11 The control group placed three layers of sterile drug-sensitive paper and found that Aspergillus niger could grow all over the drug-sensitive paper, indicating that ordinary materials have no antibacterial effect. Fig.12 It can be seen that no bacteria grow on the surface of carboxymethyl cellulose-based imidazole zwitterionic polymers in the culture medium of Aspergillus niger. Fig.13 It can be seen that no bacteria grow on the surface of the zwitterionic polymer in the culture medium of Phanerochaete chrysosporium. By comparison, it can be proved that the carboxymethyl cellulose-based imidazole zwitterionic polymer has a certain antibacterial property (during the culture, the carboxymethyl cellulose-based imidazole zwitterionic polymer sheet thickness is 1g / cm-2g / cm, the diameter is 1cm-1.5cm, the temperature is 35℃-40℃, and the time is 6-8 days. The growth of bacteria is shown in the figure. Fig.12 , Fig.13 are very similar, so I won’t go into detail).

Claims

1. A method for preparing a carboxymethyl cellulose-based imidazole zwitterionic polymer, characterized in that: The following steps are involved: Step 1, dissolving sodium carboxymethyl cellulose in a mixed solvent of DMF and water to form a mixed solution, wherein the mass concentration of sodium carboxymethyl cellulose is 27 g / L-34 g / L, and the volume ratio of DMF to water is 0.5-1:1-2; Step 2: adding a DMF solution of N-hydroxysuccinimide to the mixed solution in step 1 to carry out a reaction, wherein the mass concentration of N-hydroxysuccinimide in the DMF solution is 80 g / L-120 g / L; Step 3, adding a DMF solution of 1-(3-aminopropyl)-imidazole to the solution after the reaction in step 2 to carry out a reaction, wherein the mass concentration of 1-(3-aminopropyl)-imidazole in the DMF solution is 100 g / L-140 g / L; In the steps 1, 2 and 3, the mass ratio of sodium carboxymethyl cellulose, N-hydroxysuccinimide and 1-(3-aminopropyl)-imidazole is 8-10:4-6:5-7; Step 4, after the reaction in step 3, adding anhydrous ethanol to precipitate the sodium carboxymethyl cellulose grafted 1-(3-aminopropyl)-imidazole, then washing with a DMF solution, and vacuum drying after washing; the volume ratio of the added anhydrous ethanol to the volume of the solution after the reaction in step 3 is at least 2:1; Step 5, dissolving the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole after vacuum drying in step 4 in a dimethyl sulfoxide solution, wherein the mass concentration of the sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole is 40 g / L-50 g / L; then dropping a DMSO solution of biphenyl dichlorobenzyl to react by stirring, wherein the mass concentration of biphenyl dichlorobenzyl in the DMSO solution is 80 g / L-120 g / L; after the reaction, washing and drying are performed to obtain the final product; In the step 5, the mass ratio of the product of sodium carboxymethyl cellulose grafted with 1-(3-aminopropyl)-imidazole to biphenyl dichlorobenzyl is 2-3:1-2.

2. The method for preparing a carboxymethyl cellulose based imidazole zwitterionic polymer according to claim 1, characterized in that: In the step 2, the reaction time of sodium carboxymethyl cellulose and N-hydroxysuccinimide is 10h-12h at room temperature.

3. The method for preparing a carboxymethyl cellulose based imidazole zwitterionic polymer according to claim 1, characterized in that: In step 4, the temperature in the vacuum drying oven is controlled to be 40° C.-45° C. during vacuum drying, and the drying time is 20 h-24 h.

4. The method for preparing a carboxymethyl cellulose based imidazole zwitterionic polymer according to claim 1, characterized in that: In step 5, the DMSO solution of biphenyl dichloride is added dropwise and stirred for reaction for 12 h-16 h, wherein the reaction is stirred at room temperature for 8 h-10 h, and then the temperature is raised to 40° C.-45° C. and stirred for reaction for 4 h-6 h.

5. The method for preparing a carboxymethyl cellulose based imidazole zwitterionic polymer according to claim 1, characterized in that: In step 5, the temperature in the vacuum drying oven is controlled to be 55° C.-60° C. during drying, and the drying time is 20 h-24 h.

6. A carboxymethyl cellulose based imidazole zwitterionic polymer, characterized in that: The invention comprises a carboxymethyl cellulose based imidazole based zwitterionic polymer prepared by the method for preparing a carboxymethyl cellulose based imidazole based zwitterionic polymer according to any one of claims 1 to 5.

7. Application of a carboxymethylcellulose-based imidazole zwitterionic polymer in sewage treatment, characterized in that: The carboxymethyl cellulose-based imidazole zwitterionic polymer according to claim 6 is used to repair wastewater containing methylene blue or Congo red.

8. The use of a carboxymethyl cellulose based imidazole zwitterionic polymer in sewage treatment according to claim 7, characterized in that: The concentration of methylene blue in the sewage is 20 mg / L-25 mg / L, and the added concentration of carboxymethyl cellulose-based imidazole zwitterionic polymer is 0.5 g / L-10 g / L.

9. The use of a carboxymethyl cellulose based imidazole zwitterionic polymer in sewage treatment according to claim 7, characterized in that: The concentration of Congo red in the sewage is 20 mg / L-25 mg / L; the added concentration range of the carboxymethyl cellulose-based imidazole zwitterionic polymer is 1 g / L-15 g / L.

10. A use of a carboxymethyl cellulose-based imidazole zwitterionic polymer in an antibacterial experiment, characterized in that: The carboxymethyl cellulose-based imidazole zwitterionic polymer according to claim 6 is pressed into a sheet with a diameter of 1 cm-1.5 cm by a mold, placed in a culture dish evenly coated with a bacterial solution, and then cultured in a constant temperature incubator at 35°C-40°C for 6-8 days; the bacterial solution contains at least one of Aspergillus niger or Phanerochaete chrysosporium.

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