Sewage treatment agent and method for preparing the same

Abstract

The application discloses a sewage treatment agent and a preparation method thereof, and relates to the field of water treatment materials. In the preparation of the sewage treatment agent, chitosan is sequentially reacted with allyl diethyl phosphate, maleic anhydride and N-(2-mercapto)-guanidine to obtain functionalized chitosan; silicon dioxide is sequentially reacted with 3-bromopropyl trimethoxysilane and anthraquinone and 1,4-bis(bromomethyl)benzene to obtain modified silicon dioxide; the modified silicon dioxide and the functionalized chitosan are reacted, and then mixed with iron acetate to obtain the sewage treatment agent after being crushed. The sewage treatment agent prepared by the application has the functions of antibiosis, adsorption and degradation of organic pollutants and adsorption of metal ions.

Description

Technical Field

[0001] The present invention relates to the field of water treatment materials, in particular to a sewage treatment agent and a preparation method thereof. Background Art

[0002] With the rapid development of industrialization and urbanization, the problem of surface water pollution has become increasingly prominent and has become an important issue that needs to be urgently addressed in the current environmental protection field. Surface water pollution mainly comes from various sources such as industrial wastewater, agricultural emissions and domestic sewage. These pollutants enter surface water bodies through different pathways, which not only have a negative impact on species living in the water, but also have a negative impact on a wider range of natural organisms. Therefore, sewage treatment agents have received widespread attention.

[0003] Regarding water pollution, the most prominent pollutants are heavy metals and organic pollutants. Heavy metals are produced and released into the environment through various industrial production processes and other human activities. Due to their persistence and toxicity, their presence will have an impact on the health of biological organisms and the environment. There are many types of organic waste, which generally have complex and stable chemical structures. They are difficult to degrade and easily accumulate in large quantities, which will also have an impact on the health of biological organisms and the environment. Therefore, this application introduces a sewage treatment agent with the ability to adsorb heavy metal ions and adsorb and degrade organic pollutants and a preparation method thereof. Summary of the Invention

[0004] The purpose of the present invention is to provide a sewage treatment agent and a preparation method thereof to solve the problems existing in the prior art.

[0005] A sewage treatment agent is prepared by reacting modified silicon dioxide and functionalized chitosan, mixing the reactants with ferric acetate, and then pulverizing the mixture.

[0006] The functionalized chitosan is prepared by reacting chitosan with diethyl allyl phosphate, maleic anhydride and N-(2-mercapto)-guanidine in sequence;

[0007] The modified silicon dioxide is prepared by reacting silicon dioxide with 3-bromopropyltrimethoxysilane, anthraquinone and 1,4-bis(bromomethyl)benzene in sequence.

[0008] A method for preparing a sewage treatment agent, the method mainly comprising the following preparation steps:

[0009] (1) mixing N,N-dimethylformamide, maleic anhydride and sodium acetate in a molar ratio of 8-10:1:1, stirring at 200-300 r / min for 10-20 min, adding 9-11 times the mass of the pre-modified chitosan to the maleic anhydride, heating to 85-95℃, continuing to stir for 5.5-6.5 h under nitrogen protection, vacuum drying at -10-0℃ for 22-26 h, washing 3-5 times with deionized water, and vacuum drying at -10-0℃ for 22-26 h to obtain modified chitosan;

[0010] (2) mixing pre-modified silica, anthraquinone, 1,2-dichloroethane, ferric chloride, and 1,4-bis(bromomethyl)benzene in a mass ratio of 8-10:1:65-75:0.5-0.7:5.5-5.8, stirring at 75-85℃ and 200-300 r / min under nitrogen protection for 22-26 h, cooling to room temperature, filtering, washing 5-7 times with deionized water, and vacuum drying at 55-65℃ for 11-13 h to obtain modified silica;

[0011] (3) mixing modified silica, functionalized chitosan, and N,N-dimethylformamide in a mass ratio of 1:1:8-12, heating to 55-65℃, stirring at 200-300 r / min for 12-13 h, adding 0.2-0.3 times the mass of the modified silica to a 20% iron acetate ethanol solution, continuing to stir for 15-25 min, cooling to room temperature, vacuum drying at 55-65℃ for 22-26 h, crushing, and passing through a 5-mesh screen to obtain a sewage treatment agent.

[0012] As an optimization, the pre-modified chitosan of step (1) is prepared by mixing allyl diethyl phosphate, chitosan, and ethanol in a mass ratio of 1:2-3:16-20, stirring at 200-300 r / min and 45-55℃ under argon protection for 38-42 h, filtering, washing 3-5 times with ethanol, and vacuum drying at -10-0℃ for 11-13 h.

[0013] As an optimization, the chitosan has a molecular weight of 2000.

[0014] As an optimization, the pre-modified silica of step (2) is prepared by mixing silica, 3-bromopropyltrimethoxysilane, and isopropyl alcohol in a mass ratio of 1:0.14-0.16:10-12, adjusting the pH to 3.8-4.2 with a 0.1 mol / L acetic acid solution, stirring at 85-95℃ and 200-300 r / min for 5-7 h, filtering, washing 3-5 times with deionized water, and drying at 90-100℃ for 2-4 h.

[0015] As an optimization, the silica is 200-mesh silica.

[0016] As an optimization, the functionalized chitosan in step (3) is prepared by mixing modified chitosan, deionized water, and azobisisobutyronitrile in a mass ratio of 1:18-22:0.05-0.07, stirring at 200-300 r / min for 2-3 min, adding an N-(2-mercapto)-guanidine solution of equal mass to the modified chitosan at a uniform rate within 5-7 min, stirring at 65-75° C. for 170-190 min, adding a 2,6-di-tert-butyl-4-methylphenol solution of 0.2-0.3 times the mass of the modified chitosan, cooling to room temperature, filtering, washing with ethanol 3-5 times, and vacuum drying at -10-0° C. for 22-26 h.

[0017] As an optimization, the N-(2-mercapto)-guanidine solution is prepared by uniformly mixing N-(2-mercapto)-guanidine and deionized water in a mass ratio of 1:8-10.

[0018] As an optimization, the 2,6-di-tert-butyl-4-methylphenol solution is prepared by uniformly mixing 2,6-di-tert-butyl-4-methylphenol and ethanol in a mass ratio of 1:8 to 12.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] When preparing the sewage treatment agent, the present invention comprises the following steps: reacting chitosan with allyl diethyl phosphate, maleic anhydride and N-(2-mercapto)-guanidine in sequence to obtain functionalized chitosan; reacting silicon dioxide with 3-bromopropyltrimethoxysilane, anthraquinone and 1,4-bis(bromomethyl)benzene in sequence to obtain modified silicon dioxide; and reacting the modified silicon dioxide with the functionalized chitosan, mixing the mixture with ferric acetate and pulverizing the mixture to obtain the sewage treatment agent.

[0021] First, chitosan is reacted with allyl diethyl phosphate, maleic anhydride and N-(2-mercapto)-guanidine in sequence to prepare functionalized chitosan; phosphate is introduced onto the surface of chitosan, which can be hydrolyzed under acidic conditions to form phosphate anions, which adsorb cationic pollutants in the water, thereby accelerating the degradation efficiency of pollutants; the reaction with maleic anhydride introduces carboxyl groups onto the surface of chitosan. The carboxyl functional group has strong electrophilic properties and can undergo coordination reactions with metal ions to achieve the effect of adsorbing metal ions in wastewater. Guanidine is introduced through the reaction with N-(2-mercapto)-guanidine. Guanidine can specifically interact with the bacterial ribosomal RNA portion, blocking the normal chain reaction required for protein synthesis; it can also interact with the circular structure of bacterial DNA, inhibiting bacterial replication and reproduction, thereby improving the antibacterial effect of the material.

[0022] Secondly, silica is reacted with 3-bromopropyltrimethoxysilane and anthraquinone and 1,4-bis(bromomethyl)benzene in sequence to obtain modified silica; anthraquinone structure is introduced on the surface of silica to complex with iron ions. Iron ions can degrade organic matter under photocatalytic conditions, and because they carry positive charge, when they come into contact with the cell membrane of microorganisms, they will be electrostatically attracted to the negatively charged cell membrane, penetrate the cell membrane into the bacteria, and react with the sulfhydryl and amino groups on the proteins in the bacteria, destroying the active center of the protein, thereby causing cell death or loss of division and proliferation ability, thereby improving the antibacterial effect of the material; and the anthraquinone structure can complex with metal ions and adsorb metal ions in sewage.

[0023] Finally, the modified silica and functionalized chitosan are reacted, then mixed with ferric acetate and crushed to obtain a sewage treatment agent. The bromine group on the surface of the modified silica reacts with the tertiary amine on the surface of the functionalized chitosan to form a quaternary ammonium. The quaternary ammonium salt, as a cation, can well adsorb anionic pollutants in the water body, thereby accelerating the degradation efficiency of the pollutants. In addition, the quaternary ammonium salt can be adsorbed to the surface of the bacteria, inserting the hydrophobic group into the lipid layer, changing the permeability of the cell membrane, destroying the membrane structure, causing the leakage of intracellular substances, affecting the normal function and metabolism of the cells, and can also denature proteins, leading to cell death, thereby improving the antibacterial effect of the material. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0025] Example 1:

[0026] A method for preparing a sewage treatment agent mainly comprises the following preparation steps:

[0027] (1) Allyl diethyl phosphate, chitosan with a molecular weight of 2000 and ethanol were mixed in a mass ratio of 1:2:16, stirred at 200 r / min, 45°C under argon protection for 38 h, filtered, washed with ethanol 3 times, and vacuum dried at -10°C for 11 h to obtain pre-modified chitosan; N,N-dimethylformamide, maleic anhydride and sodium acetate were mixed in a molar ratio of 8:1:1, stirred at 200 r / min for 10 min, and pre-modified chitosan with 9 times the mass of maleic anhydride was added, heated to 85°C, stirred under nitrogen protection for 5.5 h, vacuum dried at -10°C for 22 h, washed with deionized water 3 times, and vacuum dried at -10°C for 22 h to obtain modified chitosan; N-(2-mercapto)- Guanidine and deionized water were mixed in a mass ratio of 1:8 to prepare an N-(2-mercapto)-guanidine solution; 2,6-di-tert-butyl-4-methylphenol and ethanol were mixed in a mass ratio of 1:8 to prepare a 2,6-di-tert-butyl-4-methylphenol solution; modified chitosan, deionized water, and azobisisobutyronitrile were mixed in a mass ratio of 1:18:0.05, stirred at 200 r / min for 2 minutes, and an equal amount of N-(2-mercapto)-guanidine solution of modified chitosan was added at a uniform rate within 5 minutes. The mixture was stirred at 65°C for 170 minutes, and 0.2 times the mass of 2,6-di-tert-butyl-4-methylphenol solution of modified chitosan was added. The mixture was cooled to room temperature, filtered, washed with ethanol three times, and vacuum dried at -10°C for 22 hours to prepare functionalized chitosan.

[0028] (2) 200 mesh silica, 3-bromopropyltrimethoxysilane and isopropanol were mixed in a mass ratio of 1:0.14:10, the pH was adjusted to 3.8 with 0.1 mol / L acetic acid solution, stirred at 85 ° C, 200 r / min for 5 h, filtered, washed with deionized water 3 times, and dried at 90 ° C for 2 h to obtain pre-modified silica; pre-modified silica, anthraquinone, 1,2-dichloroethane, ferric chloride, 1,4-di(bromomethyl)benzene were mixed in a mass ratio of 8:1:65:0.5:5.5, stirred at 75 ° C, 200 r / min, under nitrogen protection for 22 h, cooled to room temperature, filtered, washed with deionized water 5 times, and vacuum dried at 55 ° C for 11 h to obtain modified silica;

[0029] (3) Modified silica, functionalized chitosan and N,N-dimethylformamide were mixed in a mass ratio of 1:1:8, heated to 55°C, stirred at 200 r / min for 12 h, and a 20% iron acetate ethanol solution with a mass fraction of 0.2 times the mass of the modified silica was added. The mixture was stirred for 15 min, cooled to room temperature, vacuum dried at 55°C for 22 h, crushed, and passed through a 5-mesh sieve to obtain a sewage treatment agent.

[0030] Example 2:

[0031] A method for preparing a sewage treatment agent mainly comprises the following preparation steps:

[0032] (1) Allyl diethyl phosphate, chitosan with a molecular weight of 2000 and ethanol were mixed in a mass ratio of 1:2.5:18, stirred at 250 r / min, 50°C, under argon protection for 40 h, filtered, washed with ethanol 4 times, and vacuum dried at -5°C for 12 h to obtain pre-modified chitosan; N,N-dimethylformamide, maleic anhydride and sodium acetate were mixed in a molar ratio of 9:1:1, stirred at 250 r / min for 15 min, and pre-modified chitosan with 10 times the mass of maleic anhydride was added, heated to 90°C, stirred for 6 h under nitrogen protection, vacuum dried at -5°C for 24 h, washed with deionized water 4 times, and vacuum dried at -5°C for 24 h to obtain modified chitosan; N-(2-mercapto)-guanidine and Deionized water was mixed uniformly at a mass ratio of 1:9 to prepare an N-(2-mercapto)-guanidine solution; 2,6-di-tert-butyl-4-methylphenol and ethanol were mixed uniformly at a mass ratio of 1:10 to prepare a 2,6-di-tert-butyl-4-methylphenol solution; modified chitosan, deionized water, and azobisisobutyronitrile were mixed at a mass ratio of 1:20:0.06, stirred at 250 r / min for 2.5 minutes, and an equal amount of N-(2-mercapto)-guanidine solution of modified chitosan was added at a uniform speed within 6 minutes, stirred at 70°C for 180 minutes, and 0.25 times the mass of modified chitosan 2,6-di-tert-butyl-4-methylphenol solution was added, cooled to room temperature, filtered, washed with ethanol 4 times, and vacuum dried at -5°C for 24 hours to prepare functionalized chitosan;

[0033] (2) 200 mesh silica, 3-bromopropyltrimethoxysilane and isopropanol were mixed in a mass ratio of 1:0.15:11, the pH was adjusted to 4 with 0.1 mol / L acetic acid solution, stirred at 90 ° C, 250 r / min for 6 h, filtered, washed with deionized water 4 times, and dried at 95 ° C for 3 h to obtain pre-modified silica; pre-modified silica, anthraquinone, 1,2-dichloroethane, ferric chloride, 1,4-di(bromomethyl)benzene were mixed in a mass ratio of 9:1:70:0.6:5.7, stirred at 80 ° C, 250 r / min, under nitrogen protection for 24 h, cooled to room temperature, filtered, washed with deionized water 6 times, and vacuum dried at 60 ° C for 12 h to obtain modified silica;

[0034] (3) Modified silica, functionalized chitosan and N,N-dimethylformamide were mixed in a mass ratio of 1:1:10, heated to 60°C, stirred at 250 r / min for 12.5 h, and a 20% iron acetate ethanol solution with a mass fraction of 0.25 times the mass of the modified silica was added. The mixture was stirred for 20 min, cooled to room temperature, vacuum dried at 60°C for 24 h, crushed, and passed through a 5-mesh sieve to obtain a sewage treatment agent.

[0035] Example 3:

[0036] A method for preparing a sewage treatment agent mainly comprises the following preparation steps:

[0037] (1) Allyl diethyl phosphate, chitosan with a molecular weight of 2000 and ethanol were mixed in a mass ratio of 1:3:20, stirred at 300 r / min, 55°C under argon protection for 42 h, filtered, washed with ethanol 5 times, and vacuum dried at 0°C for 13 h to obtain pre-modified chitosan; N,N-dimethylformamide, maleic anhydride and sodium acetate were mixed in a molar ratio of 10:1:1, stirred at 300 r / min for 20 min, and pre-modified chitosan with 11 times the mass of maleic anhydride was added, heated to 95°C, stirred under nitrogen protection for 6.5 h, vacuum dried at 0°C for 26 h, washed with deionized water 5 times, and vacuum dried at 0°C for 26 h to obtain modified chitosan; N-(2-mercapto)-guanidine and Deionized water was mixed uniformly at a mass ratio of 1:10 to prepare an N-(2-mercapto)-guanidine solution; 2,6-di-tert-butyl-4-methylphenol and ethanol were mixed uniformly at a mass ratio of 1:12 to prepare a 2,6-di-tert-butyl-4-methylphenol solution; modified chitosan, deionized water, and azobisisobutyronitrile were mixed at a mass ratio of 1:22:0.07, stirred at 300 r / min for 3 minutes, and an equal amount of N-(2-mercapto)-guanidine solution of modified chitosan was added at a uniform rate within 7 minutes. The mixture was stirred at 75°C for 190 minutes, and 0.3 times the mass of 2,6-di-tert-butyl-4-methylphenol solution of modified chitosan was added. The mixture was cooled to room temperature, filtered, washed with ethanol 5 times, and vacuum dried at 0°C for 26 hours to prepare functionalized chitosan.

[0038] (2) 200 mesh silica, 3-bromopropyltrimethoxysilane and isopropanol were mixed in a mass ratio of 1:0.16:12, the pH was adjusted to 4.2 with 0.1 mol / L acetic acid solution, stirred at 95 ° C, 300 r / min for 7 h, filtered, washed with deionized water 5 times, and dried at 100 ° C for 4 h to obtain pre-modified silica; pre-modified silica, anthraquinone, 1,2-dichloroethane, ferric chloride, 1,4-di(bromomethyl)benzene were mixed in a mass ratio of 10:1:75:0.7:5.8, stirred at 85 ° C, 300 r / min, under nitrogen protection for 26 h, cooled to room temperature, filtered, washed with deionized water 7 times, and vacuum dried at 65 ° C for 13 h to obtain modified silica;

[0039] (3) Modified silica, functionalized chitosan and N,N-dimethylformamide were mixed in a mass ratio of 1:1:12, heated to 65°C, stirred at 300 r / min for 13 h, and a 20% iron acetate ethanol solution with a mass fraction of 0.3 times the mass of the modified silica was added. The mixture was stirred for 25 min, cooled to room temperature, vacuum dried at 65°C for 26 h, crushed, and passed through a 5-mesh sieve to obtain a sewage treatment agent.

[0040] Comparative Example 1:

[0041] The difference between the preparation method of the sewage treatment agent of Comparative Example 1 and Example 2 lies in the difference in step (1). Step (1) is modified as follows: allyl diethyl phosphate, chitosan with a molecular weight of 2000, and ethanol are mixed in a mass ratio of 1:2.5:18, stirred at 250 r / min, 50°C, under argon protection for 40 hours, filtered, washed with ethanol four times, and vacuum dried at -5°C for 12 hours to obtain pre-modified chitosan; N,N-dimethylformamide, maleic anhydride, and sodium acetate are mixed in a molar ratio of 9:1:1, stirred at 250 r / min for 15 minutes, pre-modified chitosan with 10 times the mass of maleic anhydride is added, the temperature is raised to 90°C, stirred under nitrogen protection for 6 hours, vacuum dried at -5°C for 24 hours, washed with deionized water four times, and vacuum dried at -5°C for 24 hours to obtain functionalized chitosan. The remaining steps are the same as those in Example 2.

[0042] Comparative Example 2:

[0043] The preparation method of the sewage treatment agent of Comparative Example 2 differs from that of Example 2 only in that chitosan is not modified. The remaining steps are the same as those of Example 2.

[0044] Comparative Example 3:

[0045] The preparation method of the sewage treatment agent of Comparative Example 3 differs from that of Example 2 in that the silica is not modified and step (3) is different. Step (3) is modified as follows: 200-mesh silica, functionalized chitosan, and N,N-dimethylformamide are mixed in a mass ratio of 1:1:10, stirred at 250 r / min for 20 min, cooled to room temperature, vacuum-dried at 60° C. for 24 h, crushed, and passed through a 5-mesh sieve to prepare the sewage treatment agent. The remaining steps are the same as those of Example 2.

[0046] Test Example 1:

[0047] Antibacterial testing:

[0048] Test method: Tested in accordance with GB / T31402-2015, using Staphylococcus aureus and Escherichia coli. Results are shown in Table 1.

[0049] Table 1

[0050]

[0051] From the comparison of the experimental data in Table 1, it can be found that the sewage treatment agent prepared by the present invention has good antibacterial ability.

[0052] From the comparison of the experimental data of Examples 1, 2, and 3 and Comparative Example 1 in Table 1, it can be found that Examples 1, 2, and 3 have high antibacterial rates. The difference between Comparative Example 1 and the Example is that guanidine is not incorporated into the chitosan surface. Guanidine can specifically interact with the bacterial ribosomal RNA portion, blocking the normal chain reaction required for protein synthesis; it can also interact with the circular structure of bacterial DNA, inhibiting bacterial replication and reproduction, thereby achieving an antibacterial effect.

[0053] From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 2, it can be found that the antibacterial rates of Examples 1, 2 and 3 are high. The difference between Comparative Example 2 and the Example is that chitosan is not modified and cannot react with bromine groups to generate quaternary ammonium salts to change the permeability of the cell membrane: quaternary ammonium salts can be adsorbed to the surface of the bacteria, inserting hydrophobic groups into the lipid layer, changing the permeability of the cell membrane, destroying the membrane structure, causing leakage of intracellular substances, affecting the normal function and metabolism of the cells, and can also denature proteins, leading to cell death, thereby achieving an antibacterial effect;

[0054] From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 3, it can be found that the antibacterial rates of Examples 1, 2, and 3 are high. The difference between Comparative Example 3 and the Examples is that no iron ions and quaternary ammonium salts are added. Iron ions are positively charged. When they come into contact with the cell membrane of microorganisms, they will be electrostatically attracted to the negatively charged cell membrane, penetrate the cell membrane and enter the interior of the bacteria, react with the sulfhydryl groups, amino groups, etc. on the proteins in the bacteria, destroy the active center of the protein, thereby causing cell death or loss of division and proliferation ability, thereby achieving an antibacterial effect.

[0055] Test Example 2:

[0056] Metal ion adsorption test:

[0057] Test method: Add 1g of sewage treatment agent to 50mL of a 20mg / L copper ion solution at room temperature. Measure the copper ion concentration after 60 minutes. The results are shown in Table 2.

[0058] Table 2

[0059] Copper ion concentration Example 1 0.8mg / L Example 2 0.6mg / L Example 3 0.7mg / L Comparative Example 1 0.8mg / L Comparative Example 2 5.8mg / L Comparative Example 3 6.9mg / L

[0060] From the comparison of the experimental data in Table 2, it can be found that the sewage treatment agent prepared by the present invention has good metal ion adsorption capacity.

[0061] From the experimental data comparison of example 1, 2, 3 and comparative example 2 in table 2, it can be found that the copper ion concentration of example 1, 2, 3 is low, and the difference between comparative example 2 and the examples is that the chitosan is not modified, and the carboxyl group is not introduced on the surface, the carboxyl functional group has strong electrophilic property, can coordinate with metal ions, and the effect of adsorbing metal ions in wastewater is achieved;

[0062] From the experimental data comparison of example 1, 2, 3 and comparative example 3, it can be found that the copper ion concentration of example 1, 2, 3 is low, and the difference between comparative example 3 and the examples is that the silica is not modified, and the anthraquinone structure on the surface of the silica can be complexed with metal ions, and the effect of adsorbing metal ions in wastewater is achieved.

[0063] Test example 3:

[0064] Organic matter adsorption and degradation test:

[0065] Test method: first, 20ppm of eosin solution and methylene blue solution are configured, 25mL of each, the pH of the methylene blue solution is adjusted to 5 by using 0.1mol / L acetic acid, then 1g of the wastewater treatment agent is put in, ultrasonic, the power of the photocatalytic device is turned on, and light is irradiated for 60min, through the change of absorbance at 665nm, the adsorption and degradation efficiency is calculated, wherein the adsorption and degradation efficiency =

(initial organic pollutant concentration-light catalytic treatment after organic pollutant concentration) / initial organic pollutant concentration

[0066] Table 3

[0067] Methylene blue adsorption degradation efficiency Eosin adsorption degradation efficiency Example 1 97.8％ 97.7％ Example 2 98.0％ 97.9％ Example 3 97.7％ 97.6％ Comparative Example 1 97.5％ 97.4％ Comparative Example 2 88.6％ 88.4％ Comparative Example 3 19.9％ 5.8％

[0068] From the experimental data comparison in table 3, it can be found that the wastewater treatment agent prepared by the application has good adsorption and degradation ability of organic pollutants.

[0069] From the experimental data comparison of example 1, 2, 3 and comparative example 2 in table 3, it can be found that the methylene blue adsorption and degradation efficiency and the eosin adsorption and degradation efficiency of example 1, 2, 3 are high, and the difference between comparative example 2 and the examples is that the chitosan is not modified, the introduced phosphate ester is hydrolyzed under acidic conditions to form phosphate anion, which can adsorb cationic pollutants in water, thereby accelerating the degradation efficiency of the pollutants, and the chitosan is not modified, which leads to the failure of the reaction of the bromine group on the surface of the modified silica and the quaternary ammonium salt to generate quaternary ammonium salt, and the quaternary ammonium salt as a cation can well adsorb anionic pollutants in water, thereby accelerating the degradation efficiency of the pollutants;

[0070] From the experimental data of Example 1, 2, 3 and Comparative Example 3 in Table 3, it can be found that the methylene blue adsorption degradation efficiency and the eosin adsorption degradation efficiency of Example 1, 2, 3 are high, and the difference between Comparative Example 3 and the examples is that the silica is not modified and the iron ions are not introduced, and the iron ions can degrade the organic matter under the condition of photocatalysis.

[0071] The above detailed description of the specific embodiments has further detailed the purposes, technical solutions and beneficial effects of the present application, and it should be understood that the above description is only a specific embodiment of the present application and is not used to limit the protection scope of the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A sewage treatment agent, characterized in that The sewage treatment agent is prepared by reacting modified silicon dioxide and functionalized chitosan, mixing with ferric acetate, and crushing. The functionalized chitosan is prepared by reacting chitosan with diethyl allyl phosphate, maleic anhydride and N-(2-mercapto)-guanidine in sequence; The modified silica is prepared by reacting silica with 3-bromopropyltrimethoxysilane, anthraquinone and 1,4-bis(bromomethyl)benzene in sequence; The preparation method of the sewage treatment agent mainly includes the following preparation steps: (1) N,N-dimethylformamide, maleic anhydride and sodium acetate were mixed in a molar ratio of 8-10:1:1, stirred at 200-300 r / min for 10-20 min, and pre-modified chitosan with a mass of 9-11 times that of maleic anhydride was added, heated to 85-95 °C, and stirred under nitrogen for 5.5-6.5 h, vacuum dried at -10-0 °C for 22-26 h, washed with deionized water for 3-5 times, and then vacuum dried at -10-0 °C for 22-26 h to obtain modified chitosan; modified chitosan, deionized water, and maleic anhydride were mixed. The mixture is mixed with diisobutyronitrile in a mass ratio of 1:18-22:0.05-0.07, stirred at 200-300 r / min for 2-3 min, and an N-(2-mercapto)-guanidine solution of equal mass to the modified chitosan is added at a uniform rate within 5-7 min. The mixture is stirred at 65-75°C for 170-190 min, and a 2,6-di-tert-butyl-4-methylphenol solution of 0.2-0.3 times the mass of the modified chitosan is added. The mixture is cooled to room temperature, filtered, washed with ethanol 3-5 times, and vacuum dried at -10-0°C for 22-26 h to obtain functionalized chitosan. (2) Pre-modified silica, anthraquinone, 1,2-dichloroethane, ferric chloride, and 1,4-di(bromomethyl)benzene were mixed in a mass ratio of 8-10:1:65-75:0.5-0.7:5.5-5.8, stirred at 75-85°C, 200-300 r / min, and nitrogen protection for 22-26 hours, cooled to room temperature, filtered, washed with deionized water 5-7 times, and vacuum dried at 55-65°C for 11-13 hours to obtain modified silica; (3) Modified silica, functionalized chitosan and N,N-dimethylformamide were mixed in a mass ratio of 1:1:8-12, heated to 55-65°C, stirred at 200-300 r / min for 12-13 h, and 0.2-0.3 times the mass of modified silica and a 20% iron acetate ethanol solution were added. The mixture was stirred for 15-25 min, cooled to room temperature, vacuum dried at 55-65°C for 22-26 h, crushed, and passed through a 5-mesh sieve to obtain a sewage treatment agent.

2. A sewage treatment agent according to claim 1, characterized in that, The pre-modified chitosan in step (1) is prepared by mixing allyl diethyl phosphate, chitosan and ethanol in a mass ratio of 1:2-3:16-20, stirring at 200-300 r / min, 45-55° C., under argon protection for 38-42 hours, filtering, washing with ethanol 3-5 times, and vacuum drying at -10-0° C. for 11-13 hours.

3. A sewage treatment agent according to claim 2, characterized in that, The chitosan has a molecular weight of 2000.

4. A sewage treatment agent according to claim 1, characterized in that, The N-(2-mercapto)-guanidine solution in step (1) is prepared by uniformly mixing N-(2-mercapto)-guanidine and deionized water in a mass ratio of 1:8-10.

5. A sewage treatment agent according to claim 1, characterized in that, The 2,6-di-tert-butyl-4-methylphenol solution in step (1) is prepared by uniformly mixing 2,6-di-tert-butyl-4-methylphenol and ethanol in a mass ratio of 1:8-12.

6. A sewage treatment agent according to claim 1, characterized in that, The pre-modified silica in step (2) is prepared by mixing silica, 3-bromopropyltrimethoxysilane and isopropanol in a mass ratio of 1:0.14-0.16:10-12, adjusting the pH to 3.8-4.2 with 0.1 mol / L acetic acid solution, stirring at 85-95° C. and 200-300 r / min for 5-7 h, filtering, washing with deionized water for 3-5 times, and drying at 90-100° C. for 2-4 h.

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