Plant-based water body filtering material and preparation method thereof

Abstract

The invention discloses a plant-based water filtering material and a preparation method thereof, and relates to the technical field of filtering materials. When the plant-based water body filtering material is prepared, 4-(10, 15, 20-triphenyl porphyrin-5-yl) aniline sequentially reacts with acrylic acid-2, 3-epoxypropyl ester and zinc acetate to obtain an alkenyl porphyrin zinc complex; the preparation method comprises the following steps: reacting chitosan with an alkenyl porphyrin zinc complex to obtain modified chitosan; reacting the oxidized reed carbon with butyl trimethyl ammonium chloride to obtain modified reed carbon; preparing a spinning solution from polybutylene terephthalate, the modified chitosan and the modified reed carbon, and performing electrostatic spinning to obtain a fiber membrane; itaconic acid and alkenyl benzisothiazolinone are prepared into a finishing solution; and finishing the fiber membrane with the finishing liquid to obtain the plant-based water filtering material. The plant-based water filtering material prepared by the invention can adsorb and catalytically degrade organic dyes in wastewater and adsorb heavy metals, and also has an antibacterial effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of filter materials, in particular to a plant-based water filter material and a preparation method thereof. BACKGROUND

[0002] Water resource recycling is an important way to solve the contradiction between supply and demand. With the change of environmental protection concept from "wastewater treatment" to "recycling", membrane water treatment will become an inevitable condition to realize water resource utilization. At present, in the field of filter materials, mainly knitted fabrics, woven fabrics and some non-woven fabrics, etc. Compared with these traditional methods, electrospun fibers have the advantages of high specific surface area, large porosity and high permeability, and therefore can be used as high-performance water treatment filter materials, and have a very wide application prospect.

[0003] Sewage, especially industrial wastewater, usually contains a large amount of heavy metal ions, microorganisms and organic dyes. Traditional filter materials have single function and only have physical adsorption effect on pollutants, which is difficult to efficiently intercept these pollution components, increases the process of water purification and occupies a large amount of manpower and material resources. The present application uses PBT with high temperature resistance and acid and alkali corrosion resistance as a base resin, and uses chitosan and reed carbon as plant-based components, and an electrospun water filter material is prepared. Through modification of chitosan and reed carbon and post-treatment process, the water filter material has excellent adsorption capacity, catalytic degradation capacity and antibacterial capacity, so that the sewage purification efficiency is greatly improved. SUMMARY

[0004] The present application aims to provide a plant-based water filter material and a preparation method thereof to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present application provides the following technical scheme: A preparation method of a plant-based water filter material, the preparation method of the plant-based water filter material comprising the following steps: (1) reacting 4-(10,15,20-triphenylporphyrin-5-yl) aniline and 2,3-epoxypropyl acrylate to obtain an alkenyl porphyrin monomer; and reacting the alkenyl porphyrin monomer and zinc acetate to obtain an alkenyl porphyrin zinc complex; (2) reacting chitosan and the alkenyl porphyrin zinc complex to obtain modified chitosan; (3) carbonizing reed straw at high temperature to obtain reed carbon; oxidizing the reed carbon with nitric acid to obtain oxidized reed carbon; and loading butyl trimethyl ammonium chloride onto the oxidized reed carbon to obtain modified reed carbon; (4) preparing a spinning solution by mixing polybutylene terephthalate, the modified chitosan and the modified reed carbon, and electrospinning to obtain a fiber membrane; (5) reacting benzisothiazolinone and 3-bromoprop-1-ene to obtain alkenyl benzisothiazolinone; (6) preparing a finishing liquid by mixing itaconic acid and alkenyl benzisothiazolinone; and finishing the fiber membrane with the finishing liquid to obtain a plant-based water filtering material.

[0006] Further, the preparation method of the alkenyl porphyrin monomer in step (1) is as follows: 4-(10, 15, 20-triphenylporphyrin-5-yl) aniline and dichloromethane are uniformly mixed at a mass ratio of 1:(30-40), stirred at room temperature for 20-30 min under nitrogen protection, 1.1-1.2 times the molar amount of 4-(10, 15, 20-triphenylporphyrin-5-yl) aniline of acrylic acid-2, 3-epoxypropyl ester is added, the temperature is raised to 40-50℃, and the reflux reaction is continued for 7-8 h, and vacuum drying is performed at 60-70℃ for 8-10 h to obtain the alkenyl porphyrin monomer.

[0007] Further, the preparation method of the alkenyl porphyrin zinc complex in step (1) is as follows: the alkenyl porphyrin monomer and dichloromethane are mixed at a mass ratio of 1:(30-40), stirred at room temperature for 20-30 min, and 2-3 times the mass of the alkenyl porphyrin monomer of zinc acetate is added, and stirred at 40-50℃ for 2-3 h, extracted with deionized water, and the organic phase is vacuum dried at 60-70℃ for 8-10 h to obtain the alkenyl porphyrin zinc complex.

[0008] Further, the chemical reaction formula of the alkenyl porphyrin zinc complex in step (1) is as follows: .

[0009] Further, the preparation method of the modified chitosan in step (2) is as follows: chitosan and N,N-dimethylformamide are uniformly mixed at a mass ratio of 1:(30-40), stirred at 40-50℃ for 10-20 min, and 1.4-1.6 times the mass of the chitosan of the alkenyl porphyrin zinc complex is added, and stirred at 70-80℃ for 20-24 h, N,N-dimethylformamide is removed by rotary evaporation under reduced pressure, washed with methanol for 3-5 times, and vacuum dried at 70-80℃ for 16-20 h to obtain the modified chitosan.

[0010] Further, the preparation method of the modified reed carbon in step (3) is as follows: the reed straws are dried at 60-80℃ for 20-24h, crushed in a crusher, and sieved through a 100-mesh screen to obtain straw powder; the straw powder is placed in a crucible, heated to 400-500℃ at a speed of 10℃ / min under nitrogen protection, kept for 60-80min, heated to 600-700℃, and kept for 2-3h, cooled to room temperature, ball-milled, and sieved through an 800-mesh screen to obtain reed carbon; the reed carbon and 10% nitric acid aqueous solution are mixed uniformly at a mass ratio of 1:(12-16), stirred at 75-85℃ for 10-14h, filtered, washed with deionized water for 3-5 times, and dried in an oven at 105-115℃ to constant weight to obtain oxidized reed carbon; the oxidized reed carbon, butyl trimethyl ammonium chloride, and methanol are mixed uniformly at a mass ratio of 1:(2-3):(10-20), ultrasonically treated at room temperature for 3-4h, filtered, and dried at 70-80℃ to constant weight to obtain modified reed carbon.

[0011] Further, the preparation method of the fiber membrane in step (4) is as follows: trifluoroacetic acid and dichloromethane are mixed uniformly at a mass ratio of 4:1 to prepare a mixed solvent; 30-40 parts of polybutylene terephthalate, 4-5 parts of modified chitosan, 3-4 parts of modified reed carbon, and 150-200 parts of the mixed solvent are weighed; the polybutylene terephthalate, the modified chitosan, the modified reed carbon, and the mixed solvent are mixed uniformly to prepare a spinning solution; and the spinning solution is electrospun on an electrospinning instrument to obtain a fiber membrane.

[0012] Further, the parameters of electrospinning are as follows: the pushing rate of the spinning solution is 0.002-0.004mm / s, the spinning voltage is 22-26kV, and the receiving distance is 8-10cm.

[0013] Further, the preparation method of the alkenyl benzisothiazolinone in step (5) is as follows: benzisothiazolinone, 3-bromoprop-1-ene, and potassium carbonate are added into acetonitrile in a volume of 20-30 times the mass of the benzisothiazolinone at a molar ratio of 1:1:(1.1-1.3), stirred at 55-65℃ for 3-4h, mixed uniformly with deionized water in a volume of 2-3 times the volume of acetonitrile after the reaction is completed, extracted with ethyl acetate, and dried at 70-80℃ under vacuum for 10-12h to obtain alkenyl benzisothiazolinone.

[0014] Further, the chemical reaction formula of the alkenyl benzisothiazolinone is as follows: .

[0015] Further, the preparation method of the plant-based water filtration material in step (6) is as follows: itaconic acid, alkenylbenzisothiazolinone, and acetone are mixed evenly in a mass ratio of 1:(0.4~0.6):(13~15), stirred at room temperature for 10~20 min, and benzoyl peroxide with a mass of 0.05~0.07 times that of itaconic acid is added to prepare a finishing solution; the fiber membrane is immersed in the finishing solution with a bath ratio of 1:(20~30), kept at 65~75℃ for 60~80 min, taken out, and dried at 70~80℃ to constant weight to obtain the plant-based water filtration material.

[0016] This invention also provides a plant-based water filtration material prepared by the above-described method.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: First, an alkenyl porphyrin monomer is obtained by reacting 4-(10,15,20-triphenylporphyrin-5-yl)aniline with 2,3-epoxypropyl acrylate. The alkenyl porphyrin monomer is then reacted with zinc acetate to obtain an alkenyl porphyrin zinc complex. An α,β-unsaturated double bond is introduced into the alkenyl porphyrin zinc complex. The alkenyl porphyrin zinc complex is then reacted with an amino group on chitosan via Michael addition to graft the porphyrin zinc complex onto chitosan. The porphyrin zinc complex endows the filter membrane with photocatalytic degradation properties for organic dyes.

[0018] Second, reed stalks are carbonized at high temperature to obtain reed charcoal; nitric acid is used as an oxidant to oxidize the reed charcoal, increasing the content of carboxylic acid groups in the reed charcoal; butyltrimethylammonium chloride is loaded onto the oxidized reed charcoal through electrostatic interaction to obtain modified reed charcoal; reed charcoal is a biochar material with a large number of oxygen-containing functional groups on its surface, which can adsorb heavy metals and organic dyes. Oxidizing reed charcoal can increase the content of carboxylic acid groups in the reed charcoal, further improving the adsorption effect of the reed charcoal. By loading cationic antibacterial agents onto the reed charcoal through electrostatic interaction, the antibacterial function of the filter membrane material can be further improved.

[0019] Third, benzisothiazolinone and 3-bromoprop-1-ene are reacted to obtain alkenylbenzisisothiazolinone; itaconic acid and alkenylbenzisisothiazolinone are formulated into a finishing solution; the fiber membrane is finished with the finishing solution to obtain a plant-based water filtration material; a grafting reaction is carried out on the surface of the filter membrane to introduce carboxylic acid groups and benzisothiazolinone groups into the surface of the fiber membrane. The benzisothiazolinone groups have antibacterial activity, which can further enhance the antibacterial ability of the filter membrane. At the same time, the large number of carboxyl groups grafted on the surface can further enhance the adsorption effect of the filter membrane. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0021] In the following examples and comparative examples, the polybutylene terephthalate used was purchased from Liaoyang Petrochemical Company.

[0022] Example 1: A method for preparing a plant-based water filtration material includes the following preparation steps: (1) 4-(10,15,20-triphenylporphyrin-5-yl)aniline and dichloromethane were mixed evenly at a mass ratio of 1:30. Under nitrogen protection, the mixture was stirred at room temperature for 20 min. 2,3-glycidyl acrylate with a molar weight of 1.1 times that of 4-(10,15,20-triphenylporphyrin-5-yl)aniline was added. The mixture was heated to 40 °C and stirred under reflux for 8 h. The mixture was then dried under vacuum at 60 °C for 10 h to obtain an alkenylporphyrin monomer. Alkenylporphyrin monomer and dichloromethane were mixed at a mass ratio of 1:30. The mixture was stirred at room temperature for 20 min. 2 times the mass of zinc acetate was added. The mixture was stirred under reflux at 40 °C for 3 h. The mixture was extracted with deionized water. The organic phase was dried under vacuum at 60 °C for 10 h to obtain an alkenylporphyrin zinc complex. (2) Chitosan and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:30 and stirred at 40°C for 20 min. Then, 1.4 times the mass of the chitosan was added to the alkenyl porphyrin zinc complex and stirred at 70°C for 24 h. The N,N-dimethylformamide was removed by rotary evaporation under reduced pressure. The mixture was washed three times with methanol and dried under vacuum at 70°C for 20 h to obtain modified chitosan. (3) Dry reed stalks at 60℃ for 24h, crush them in a crusher, and pass them through a 100-mesh sieve to obtain stalk powder; place the stalk powder in a crucible, heat it to 400℃ at a rate of 10℃ / min under nitrogen protection, keep it at 40℃ for 80min, heat it to 600℃, keep it at 600℃ for 3h, cool it to room temperature, ball mill it, and pass it through an 800-mesh sieve to obtain reed char; mix the reed char and a 10% nitric acid aqueous solution at a mass ratio of 1:12, stir and react at 75℃ for 14h, filter, wash with deionized water 3 times, and dry it in an oven at 105℃ to constant weight to obtain oxidized reed char; mix the oxidized reed char, butyltrimethylammonium chloride, and methanol at a mass ratio of 1:2:10, sonicate it at room temperature for 3h, filter it, and dry it at 70℃ to constant weight to obtain modified reed char; (4) Trifluoroacetic acid and dichloromethane are mixed evenly in a mass ratio of 4:1 to prepare a mixed solvent; 30 parts of polybutylene terephthalate, 4 parts of modified chitosan, 3 parts of modified reed charcoal and 150 parts of mixed solvent are weighed by mass; polybutylene terephthalate, modified chitosan, modified reed charcoal and mixed solvent are mixed evenly to prepare a spinning solution; the spinning solution is electrospun on an electrospinning apparatus to obtain a fiber membrane; the spinning solution push rate of electrospinning is 0.003 mm / s, the spinning voltage is 24 kV and the receiving distance is 10 cm; (5) Add benzisothiazolinone, 3-bromoprop-1-ene and potassium carbonate in a molar ratio of 1:1:1.1 to acetonitrile in 20 times the mass of benzisothiazolinone. Stir at 55°C for 4 hours. After the reaction is complete, add deionized water in 2 times the volume of acetonitrile and mix well. Then extract with ethyl acetate, take the organic phase and dry it under vacuum at 70°C for 12 hours to obtain alkenyl benzisothiazolinone. (6) Mix itaconic acid, alkenylbenzisothiazolinone and acetone in a mass ratio of 1:0.4:13, stir at room temperature for 10 min, add 0.05 times the mass of itaconic acid with benzoyl peroxide to prepare a finishing solution; immerse the fiber membrane in the finishing solution with a bath ratio of 1:20, keep it at 65℃ for 80 min, take it out, and dry it at 70℃ to constant weight to obtain plant-based water filtration material.

[0023] Example 2: A method for preparing a plant-based water filtration material includes the following preparation steps: (1) 4-(10,15,20-triphenylporphyrin-5-yl)aniline and dichloromethane were mixed evenly at a mass ratio of 1:35. Under nitrogen protection, the mixture was stirred at room temperature for 25 min. Then, 2,3-epoxypropyl acrylate with a molar weight of 1.15 times that of 4-(10,15,20-triphenylporphyrin-5-yl)aniline was added. The mixture was heated to 45 °C and stirred under reflux for 7.5 h. The mixture was then dried under vacuum at 65 °C for 9 h to obtain an alkenylporphyrin monomer. Alkenylporphyrin monomer and dichloromethane were mixed at a mass ratio of 1:35. The mixture was stirred at room temperature for 25 min. Then, zinc acetate with a mass weight of 2.5 times that of alkenylporphyrin monomer was added. The mixture was stirred under reflux at 45 °C for 2.5 h. The mixture was extracted with deionized water. The organic phase was dried under vacuum at 65 °C for 9 h to obtain an alkenylporphyrin zinc complex. (2) Chitosan and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:35 and stirred at 45°C for 15 min. Then, an alkenyl porphyrin zinc complex with a mass of 1.5 times that of chitosan was added and stirred at 75°C for 22 h. The N,N-dimethylformamide was removed by rotary evaporation under reduced pressure. The mixture was washed four times with methanol and dried under vacuum at 75°C for 18 h to obtain modified chitosan. (3) Dry reed stalks at 70℃ for 22h, crush them in a crusher, and pass them through a 100-mesh sieve to obtain stalk powder; place the stalk powder in a crucible, heat it to 450℃ at a rate of 10℃ / min under nitrogen protection, keep it at 450℃ for 70min, heat it to 650℃, keep it at 650℃ for 2.5h, cool it to room temperature, ball mill it, and pass it through an 800-mesh sieve to obtain reed char; mix the reed char and 10% nitric acid aqueous solution at a mass ratio of 1:14, stir and react at 80℃ for 12h, filter, wash with deionized water 4 times, and dry it in an oven at 110℃ to constant weight to obtain oxidized reed char; mix the oxidized reed char, butyltrimethylammonium chloride and methanol at a mass ratio of 1:2.5:15, sonicate it at room temperature for 3.5h, filter it, and dry it at 75℃ to constant weight to obtain modified reed char; (4) Trifluoroacetic acid and dichloromethane are mixed evenly in a mass ratio of 4:1 to prepare a mixed solvent; 35 parts of polybutylene terephthalate, 4.5 parts of modified chitosan, 3.5 parts of modified reed charcoal, and 175 parts of mixed solvent are weighed by mass; polybutylene terephthalate, modified chitosan, modified reed charcoal, and mixed solvent are mixed evenly to prepare a spinning solution; the spinning solution is electrospun on an electrospinning apparatus to obtain a fiber membrane; the spinning solution push rate of electrospinning is 0.003 mm / s, the spinning voltage is 24 kV, and the receiving distance is 10 cm; (5) Add benzisothiazolinone, 3-bromoprop-1-ene and potassium carbonate in a molar ratio of 1:1:1.2 to acetonitrile in 25 times the mass of benzisothiazolinone. Stir at 60°C for 3.5 h. After the reaction is complete, add 2.5 times the volume of deionized water to the acetonitrile and mix well. Then extract with ethyl acetate, take the organic phase and dry it under vacuum at 75°C for 11 h to obtain alkenyl benzisothiazolinone. (6) Mix itaconic acid, alkenylbenzisothiazolinone and acetone in a mass ratio of 1:0.5:14, stir at room temperature for 15 min, add 0.06 times the mass of itaconic acid with benzoyl peroxide to prepare a finishing solution; immerse the fiber membrane in the finishing solution with a bath ratio of 1:25, keep it at 70℃ for 70 min, take it out, and dry it at 75℃ to constant weight to obtain plant-based water filtration material.

[0024] Example 3: A method for preparing a plant-based water filtration material includes the following preparation steps: (1) 4-(10,15,20-triphenylporphyrin-5-yl)aniline and dichloromethane were mixed evenly at a mass ratio of 1:40. Under nitrogen protection, the mixture was stirred at room temperature for 30 min. 2,3-glycidyl acrylate with a molar weight of 1.2 times that of 4-(10,15,20-triphenylporphyrin-5-yl)aniline was added. The mixture was heated to 50 °C and stirred under reflux for 7 h. The mixture was then dried under vacuum at 70 °C for 8 h to obtain an alkenylporphyrin monomer. Alkenylporphyrin monomer and dichloromethane were mixed at a mass ratio of 1:40 and stirred at room temperature for 30 min. 3 times the mass of zinc acetate was added. The mixture was stirred under reflux at 50 °C for 2 h. The mixture was extracted with deionized water. The organic phase was dried under vacuum at 70 °C for 8 h to obtain an alkenylporphyrin zinc complex. (2) Chitosan and N,N-dimethylformamide were mixed evenly at a mass ratio of 1:40 and stirred at 50°C for 20 min. Then, an alkenyl porphyrin zinc complex with a mass of 1.6 times that of chitosan was added and stirred at 80°C for 20 h. The N,N-dimethylformamide was removed by rotary evaporation under reduced pressure. The mixture was washed 5 times with methanol and dried under vacuum at 80°C for 16 h to obtain modified chitosan. (3) Dry reed stalks at 80℃ for 20h, crush them in a crusher, and pass them through a 100-mesh sieve to obtain stalk powder; place the stalk powder in a crucible, heat it to 500℃ at a rate of 10℃ / min under nitrogen protection, keep it at 50℃ for 60min, heat it to 700℃, keep it at 70℃ for 2h, cool it to room temperature, ball mill it, and pass it through an 800-mesh sieve to obtain reed char; mix the reed char and 10% nitric acid aqueous solution at a mass ratio of 1:16, stir and react at 85℃ for 10h, filter, wash with deionized water 5 times, and dry it in an oven at 115℃ to constant weight to obtain oxidized reed char; mix the oxidized reed char, butyltrimethylammonium chloride and methanol at a mass ratio of 1:3:20, sonicate it at room temperature for 4h, filter it, and dry it at 80℃ to constant weight to obtain modified reed char; (4) Trifluoroacetic acid and dichloromethane are mixed evenly in a mass ratio of 4:1 to prepare a mixed solvent; according to the mass fraction, 40 parts of polybutylene terephthalate, 5 parts of modified chitosan, 4 parts of modified reed charcoal, and 200 parts of mixed solvent are weighed; polybutylene terephthalate, modified chitosan, modified reed charcoal, and mixed solvent are mixed evenly to prepare a spinning solution; the spinning solution is electrospun on an electrospinning apparatus to obtain a fiber membrane; the spinning solution push rate of electrospinning is 0.003 mm / s, the spinning voltage is 24 kV, and the receiving distance is 10 cm; (5) Add benzisothiazolinone, 3-bromoprop-1-ene and potassium carbonate in a molar ratio of 1:1:1.3 to acetonitrile in 30 times the mass of benzisothiazolinone. Stir at 65°C for 3 hours. After the reaction is complete, add 3 times the volume of deionized water to the acetonitrile and mix well. Then extract with ethyl acetate, take the organic phase and dry it under vacuum at 80°C for 10 hours to obtain alkenyl benzisothiazolinone. (6) Mix itaconic acid, alkenylbenzisothiazolinone and acetone in a mass ratio of 1:0.6:15, stir at room temperature for 20 min, add 0.07 times the mass of itaconic acid with benzoyl peroxide to prepare a finishing solution; immerse the fiber membrane in the finishing solution with a bath ratio of 1:30, keep it at 75℃ for 60 min, take it out, and dry it at 80℃ to constant weight to obtain plant-based water filtration material.

[0025] Comparative Example 1: The difference between the preparation method of the plant-based water filtration material in Comparative Example 1 and Example 2 is that steps (1) and (2) are not performed in Comparative Example 1, that is, chitosan is not modified, and chitosan is used instead of modified chitosan in step (4).

[0026] Comparative Example 2: The difference between the preparation method of the plant-based water filtration material in Comparative Example 2 and that in Example 2 is that in step (3) of Comparative Example 2, the reed charcoal was not subsequently modified, and in step (4) the reed charcoal was used instead of the modified reed charcoal.

[0027] Comparative Example 3: The difference between the preparation method of the plant-based water filtration material in Comparative Example 3 and that in Example 2 is that Comparative Example 3 did not perform step (5), and when preparing the finishing liquid in step (6), alkenylbenzisothiazolinone was not added.

[0028] Comparative Example 4: The difference between the preparation method of the plant-based water filtration material in Comparative Example 4 and that in Example 2 is that in step (6) of Comparative Example 4, itaconic acid is not added when preparing the finishing solution.

[0029] Test Example 1 Testing of heavy metal adsorption performance: Construction of the standard curve: Weigh 0.50 g of copper nitrate and dilute to 500 mL. Then, transfer 1.25 mL, 5 mL, 10 mL, 12.5 mL, 20 mL, and 25 mL of each solution and dilute to 25 mL to prepare copper solutions of different concentrations. Add an equal volume of 25 mM disodium ethylenediaminetetraacetate to complex the copper nitrate. Using distilled water as a reference solution, measure the UV-vis absorption spectrum of the complexed solution. The scanning speed is 2 nm / min, and the scanning range is 190–1100 nm. Measure the absorbance of solutions with different copper ion concentrations and plot the absorbance-concentration curve.

[0030] The examples and comparative samples were cut into circular samples with a diameter of 50 mm and fixed with a filter membrane fixing device. Copper nitrate and deionized water were mixed to prepare a copper solution with a concentration of 100 mg / L. 200 mL of the copper solution was taken. The copper solution was controlled to pass through the filter membrane by a peristaltic pump. The flow rate was controlled at 2 mL / min, and the solution was circulated and filtered for 3 hours. 20 mL of the filtered filtrate was taken, and an equal volume of 25 mM disodium ethylenediaminetetraacetate was added to complex it. The absorbance at the maximum absorption wavelength was measured using a UV-Vis spectrophotometer. The copper ion concentration before and after filtration was calculated according to the standard curve. The copper ion adsorption efficiency was calculated as follows: Copper ion adsorption efficiency = (copper ion concentration before filtration - copper ion concentration after filtration) / copper ion concentration before filtration × 100%. The experimental results are shown in Table 1.

[0031] Table 1 Copper ion adsorption efficiency Copper ion adsorption efficiency Example 1 85.5% Comparative Example 1 84.9% Example 2 85.7% Comparative Example 2 70.6% Example 3 86.2% Comparative Example 3 83.6% Comparative Example 4 63.7% Analyzing the experimental data in Table 1, it can be seen that the copper ion adsorption rates of Examples 1-3 are all greater than 80%, showing good adsorption effects. However, the copper ion adsorption rate of Comparative Example 2 is significantly lower than that of Example 2. This is because reed charcoal is a biomass charcoal material with a large number of oxygen-containing functional groups on its surface, which can adsorb heavy metals. Oxidating the reed charcoal with nitric acid can increase the content of carboxylic acid groups in the reed charcoal, further enhancing its adsorption effect. The copper ion adsorption rate of Comparative Example 4 is also significantly lower than that of Example 2. This is because itaconic acid is prepared as a finishing solution; the fiber membrane is finished with the finishing solution to obtain a plant-based water filtration material; and a grafting reaction is carried out on the surface of the filter membrane to introduce a large number of carboxylic acid groups onto the surface of the fiber membrane, further enhancing the adsorption effect of the filter membrane.

[0032] Test Example 2 Tests for adsorption and degradation of dyes: The samples from the examples and comparative examples were cut into 3cm × 3cm specimens. Methylene blue was dissolved in deionized water to prepare a dye solution with a concentration of 15 mg / L. 100 mL of the dye solution was added to the sample, stirred at 500 rpm for 10 hours, and then irradiated under a xenon lamp for 2 hours. Samples were taken, centrifuged, and the absorbance of the dye in the solution before and after the experiment was measured using a UV-Vis spectrophotometer to obtain the dye concentration. The dye removal rate was calculated as follows: Dye removal rate = (Dye concentration before experiment - Dye concentration after experiment) / Dye concentration before experiment × 100%. The experimental results are shown in Table 2.

[0033] Table 2 Dye removal efficiency Dye removal efficiency Example 1 93.7% Comparative Example 1 77.2% Example 2 95.5% Comparative Example 2 84.6% Example 3 95.2% Comparative Example 3 94.6% Comparative Example 4 73.5% Analyzing the experimental data in Table 2, the dye removal rates of Examples 1-3 were significantly higher than those of Comparative Example 1. This is because an alkenyl porphyrin monomer was obtained by reacting 4-(10,15,20-triphenylporphyrin-5-yl)aniline with 2,3-epoxypropyl acrylate; an alkenyl porphyrin zinc complex was obtained by reacting the alkenyl porphyrin monomer with zinc acetate; α,β-unsaturated double bonds were introduced into the alkenyl porphyrin zinc complex; and the alkenyl porphyrin zinc complex was then reacted with the amino groups on chitosan via Michael addition to graft the porphyrin zinc complex onto chitosan. The porphyrin zinc complex endowed the filter membrane with photocatalytic degradation properties of organic dyes. The dye removal rates of Examples 1-3 were significantly higher than those of Comparative Example 2 because the reed charcoal was oxidized using nitric acid as an oxidant, increasing the content of carboxylic acid groups in the reed charcoal and further enhancing its adsorption effect on dyes. The dye removal rates of Examples 1-3 were significantly higher than those of Comparative Example 4. This is because itaconic acid was formulated into a finishing solution; the fiber membrane was finished with the finishing solution to obtain a plant-based water filtration material; and a grafting reaction was carried out on the surface of the filter membrane to introduce carboxylic acid groups onto the surface of the fiber membrane, which could further improve the adsorption effect of the filter membrane.

[0034] Test Example 3 Antibacterial performance testing: Antibacterial tests were conducted using the shaking method as described in standard GB / T 20944.3-2008, and the inhibition rate was calculated. The test strain used was *Escherichia coli*. The test results are shown in Table 3.

[0035] Table 3 Bacteriostatic rate Bacteriostatic rate Example 1 ＞99% Comparative Example 1 98.92% Example 2 ＞99% Comparative Example 2 86.42% Example 3 ＞99% Comparative Example 3 81.57% Comparative Example 4 98.16% Analyzing the experimental data in Table 3, the antibacterial rates of Examples 1-3 were significantly higher than those of Comparative Example 2. This is because the reed stalks were carbonized at high temperature to obtain reed char; the reed char was oxidized using nitric acid as an oxidant, increasing the content of carboxylic acid groups in the reed char; and butyltrimethylammonium chloride was loaded onto the oxidized reed char through electrostatic interaction to obtain modified reed char. Butyltrimethylammonium chloride is a cationic antibacterial agent, which can further improve the antibacterial function of the filter membrane material. The antibacterial rates of Examples 1-3 were significantly higher than those of Comparative Example 3 because the alkenylbenzisothiazolinone was obtained by reacting benzisothiazolinone and 3-bromoprop-1-ene; the alkenylbenzisothiazolinone was formulated into a finishing solution; the fiber membrane was finished with the finishing solution to obtain a plant-based water filtration material; and a grafting reaction was performed on the surface of the filter membrane material to introduce benzisothiazolinone groups onto the surface of the fiber membrane. The benzisothiazolinone groups have antibacterial activity, which can further enhance the antibacterial ability of the filter membrane material.

[0036] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a plant-based water filtration material, characterized in that, The preparation method of the plant-based water filtration material includes the following steps: (1) 4-(10,15,20-triphenylporphyrin-5-yl)aniline and 2,3-epoxypropyl acrylate were reacted to obtain an alkenylporphyrin monomer; the alkenylporphyrin monomer and zinc acetate were reacted to obtain an alkenylporphyrin zinc complex; (2) Modified chitosan was obtained by reacting chitosan and alkenylporphyrin zinc complex; (3) Carbonize reed stalks at high temperature to obtain reed char; oxidize reed char with nitric acid to obtain oxidized reed char; load butyltrimethylammonium chloride onto oxidized reed char to obtain modified reed char; (4) Polybutylene terephthalate, modified chitosan and modified reed charcoal were prepared into a spinning solution and electrospun to obtain a fiber membrane. (5) Benzisothiazolinone and 3-bromoprop-1-ene are reacted to obtain alkenylbenzisothiazolinone; (6) Prepare finishing solution by mixing itaconic acid and alkenylbenzisothiazolinone; finish the fiber membrane with finishing solution to obtain plant-based water filtration material.

2. The method for preparing the plant-based water filtration material as described in claim 1, characterized in that, The preparation method of the alkenyl porphyrin monomer in step (1) is as follows: 4-(10,15,20-triphenylporphyrin-5-yl)aniline and dichloromethane are mixed evenly, stirred at room temperature for 20-30 min under nitrogen protection, 2,3-epoxypropyl acrylate is added, the temperature is raised to 40-50℃, and the stirring and reflux reaction is continued for 7-8 h. After drying, the alkenyl porphyrin monomer is obtained.

3. The method for preparing a plant-based water filtration material as described in claim 1, characterized in that, The preparation method of the alkenyl porphyrin zinc complex in step (1) is as follows: mix alkenyl porphyrin monomer and dichloromethane, stir at room temperature for 20-30 min, add zinc acetate, stir and reflux at 40-50℃ for 2-3 h, extract with deionized water, take the organic phase, dry, and obtain alkenyl porphyrin zinc complex.

4. The method for preparing a plant-based water filtration material as described in claim 1, characterized in that, The modified chitosan in step (2) is prepared by mixing chitosan and N,N-dimethylformamide evenly, stirring at 40~50℃ for 10~20 min, adding alkenyl porphyrin zinc complex, stirring and reacting at 70~80℃ for 20~24 h, rotary evaporating under reduced pressure, washing, drying, and obtaining modified chitosan.

5. The method for preparing a plant-based water filtration material as described in claim 1, characterized in that, The preparation method of the modified reed charcoal in step (3) is as follows: Dry the reed stalks for 20-24 hours, crush them in a crusher, and sieve them to obtain stalk powder; place the stalk powder in a crucible, heat it to 400-500℃ under nitrogen protection, keep it at that temperature for 60-80 minutes, heat it to 600-700℃, keep it at that temperature for 2-3 hours, cool it to room temperature, ball mill it, and sieve it to obtain reed charcoal; mix the reed charcoal and a 10% nitric acid aqueous solution at a mass ratio of 1:(12-16), stir and react them at 75-85℃ for 10-14 hours, filter, wash, and dry them to obtain oxidized reed charcoal; mix the oxidized reed charcoal, butyltrimethylammonium chloride, and methanol evenly, sonicate them at room temperature for 3-4 hours, filter, and dry them to obtain modified reed charcoal.

6. The method for preparing a plant-based water filtration material as described in claim 1, characterized in that, The method for preparing the fiber membrane in step (4) is as follows: trifluoroacetic acid and dichloromethane are mixed evenly to prepare a mixed solvent; 30-40 parts of polybutylene terephthalate, 4-5 parts of modified chitosan, 3-4 parts of modified reed charcoal, and 150-200 parts of mixed solvent are weighed by mass; polybutylene terephthalate, modified chitosan, modified reed charcoal, and mixed solvent are mixed evenly to prepare a spinning solution; the spinning solution is electrospun on an electrospinning apparatus to obtain a fiber membrane.

7. The method for preparing a plant-based water filtration material as described in claim 1, characterized in that, The preparation method of the alkenylbenzisothiazolinone in step (5) is as follows: add benzisothiazolinone, 3-bromoprop-1-ene and potassium carbonate to acetonitrile, stir at 55~65℃ for 3~4h, add deionized water after the reaction is completed and mix evenly, then extract with ethyl acetate, take the organic phase, dry it, and obtain alkenylbenzisothiazolinone.

8. The method for preparing a plant-based water filtration material as described in claim 7, characterized in that, The chemical reaction formula for the alkenylbenzisisothiazolinone is as follows: 。 9. The method for preparing a plant-based water filtration material as described in claim 1, characterized in that, The preparation method of the plant-based water filtration material in step (6) is as follows: mix itaconic acid, alkenylbenzisothiazolinone and acetone evenly, stir at room temperature for 10-20 min, add benzoyl peroxide to prepare a finishing solution; immerse the fiber membrane in the finishing solution with a bath ratio of 1:(20-30), keep it at 65-75℃ for 60-80 min, take it out, dry it, and obtain the plant-based water filtration material.

10. A plant-based water filtration material prepared by a method according to any one of claims 1 to 9.

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