Composite sewage treatment agent as well as preparation method and application thereof

Abstract

The invention discloses a composite sewage treatment agent as well as a preparation method and application thereof, and relates to the technical field of water treatment. When the composite sewage treatment agent is prepared, firstly, 1, 3, 6, 8-pyrene tetrasulfonic acid tetrasodium salt is treated through thionyl chloride and then reacts with hydrazine hydrate to obtain pyrene sulfonyl hydrazide, and oxidized cellulose, pyrene sulfonyl hydrazide and polyethylene glycol react to obtain porous cellulose; secondly, reacting the maleic anhydride esterified starch with 4-mercaptophthalonitrile, then carrying out ammonia gas treatment, and then reacting with boron chloride subphthalocyanine to obtain modified starch; finally, mixing the modified cellulose, the modified starch and an initiator to obtain the composite sewage treatment agent. The composite sewage treatment agent prepared by the invention has good adsorbability, antibacterial property and photocatalytic degradation property.

Description

Technical Field

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

[0002] Water is the source of life and a necessary condition for the continuation of life. The rapid increase in population and the resulting expansion of industry and agriculture have made water pollution increasingly serious. Pollutants in water mainly include heavy metal ions, microorganisms, organic dyes, aromatic compounds, etc. Currently, commonly used water treatment methods include inorganic coagulants, organic sewage treatment agents, and adsorbents. However, these agents present several challenges during use, such as the high dosage of inorganic coagulants and the resulting sludge volume; the potential for secondary pollution from organic sewage treatment agents, and the poor stability of adsorbents. Combining other water treatment methods with sewage treatment agents, such as photocatalysis, is expected to further improve water treatment efficiency. Therefore, the development of a new, highly efficient, environmentally friendly, and antibacterial sewage treatment agent is of great practical significance. Summary of the Invention

[0003] The purpose of the present invention is to provide a composite sewage treatment agent and a preparation method thereof to solve the problems existing in the prior art.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: A composite sewage treatment agent is obtained by a mixed reaction of modified cellulose, modified starch and an initiator.

[0005] As an optimization, the modified cellulose is a porous cellulose obtained by reacting oxidized cellulose, pyrenesulfonylhydrazide, and polyethylene glycol, and then treated with maleic anhydride; the pyrenesulfonylhydrazide is obtained by treating 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt with thionyl chloride and reacting with hydrazine hydrate.

[0006] As an optimization, the modified starch is obtained by reacting maleic anhydride esterified starch with 4-mercaptophthalonitrile, then treating with ammonia gas, and then reacting with boron chloride subphthalocyanine.

[0007] A method for preparing a composite sewage treatment agent comprises the following steps: (1) 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt, N,N-dimethylformamide, and 0.1 mol / L hydrogen chloride-ether solution are mixed in a mass ratio of 1:(20-30):(2-3). At 0°C, thionyl chloride in an amount 5-6 times the mass of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt is added and stirred for 3-4 hours. After the stirring is completed, an ice-water mixture in an amount 3-4 times the mass of N,N-dimethylformamide is added for precipitation, and pyrenesulfonyl chloride is obtained by suction filtration. At -5-0°C, pyrenesulfonyl chloride, 85wt% hydrazine hydrate solution, and tetrahydrofuran are mixed in a mass ratio of 1:(0.4-0.6):(15-20) for 3-5 minutes. After the temperature is raised to room temperature, stirring is continued for 3 hours. After the stirring is completed, an ice-water mixture in an amount 3-4 times the mass of tetrahydrofuran is added for precipitation, and pyrenesulfonyl hydrazide is obtained by suction filtration. (2) Mix aldehyde-modified cellulose, polyethylene glycol, pure water, and tetrahydrofuran in a mass ratio of 1:(0.05-0.1):(5-6):(10-12), heat to 45°C and stir evenly, add 3-4 times the mass of aldehyde-modified cellulose pyrenesulfonylhydrazine and 0.02-0.03 times the mass of aldehyde-modified cellulose lanthanum trifluoromethanesulfonate and react for 1-2 hours. After the reaction, cool to room temperature, filter and immerse in pure water for 48 hours, and then filter and dry to obtain porous cellulose; (3) Porous cellulose and 15 wt% sodium hydroxide solution were mixed at a mass ratio of 1:20 for 30 minutes, filtered and washed with pure water for 6 times, the washed porous cellulose and N,N-dimethylformamide were mixed at a mass ratio of 1:20 for 12 hours, filtered to obtain activated porous cellulose, the activated porous cellulose, anhydrous lithium chloride, and N,N-dimethylformamide were mixed at a mass ratio of 1:(1-2):(20-30), heated to 50-60 ° C and stirred for 5-10 minutes, maleic anhydride 0.5-0.7 times the mass of the activated porous cellulose was added, reacted at 50-60 ° C for 5-6 hours, and freeze-dried after the reaction to obtain modified cellulose; (4) Maleic anhydride esterified starch, 4-mercaptophthalonitrile, azobisisobutyronitrile and dimethyl sulfoxide were mixed in a mass ratio of 1: (0.2-0.3): (0.02-0.03): (30-40), heated to 90 ° C under nitrogen protection for 3-4 hours, cooled to room temperature after the reaction, and vacuum dried by rotary evaporation to obtain phthalonitrile starch; phthalonitrile starch and methanol were mixed in a mass ratio of 1: (20-30), and phthalonitrile was added. Ammonia gas is introduced into a mixture of 0.1 times the mass of sodium cyanide starch at room temperature for 1 hour, the temperature is raised to 60°C, and the ammonia gas is continued to react for 5 hours. After the reaction is completed, the toluene is removed by vacuum rotary evaporation to obtain pre-modified starch; the pre-modified starch, boron chloride subphthalocyanine, and dimethyl sulfoxide / 1-chloronaphthalene solution are mixed in a mass ratio of 1:(0.5-0.7):(30-40), heated to 80-90°C under nitrogen protection, and reacted for 24 hours. After the reaction is completed, the modified starch is obtained by vacuum rotary evaporation; (5) Weigh the following raw materials: 10-15 parts by mass of modified cellulose, 5-10 parts by mass of modified starch, 0.3-0.5 parts by mass of initiator, and 50-70 parts by mass of pure water. Mix the modified cellulose and modified starch, add pure water and stir, then add the initiator and react at 70-80°C for 2-4 hours. Then, evaporate under reduced pressure to obtain a composite sewage treatment agent.

[0008] As an optimization, the preparation method of the aldehyde-modified cellulose in step (2) is as follows: cellulose and acetic acid solution with a pH of 4.5 are mixed in a mass ratio of 1:20, sodium periodate is added, and the molar ratio of sodium periodate to cellulose glucose unit is 1.2:1, and the mixture is reacted at 37°C in the dark for 4 hours, ethylene glycol is added and stirred for 4 hours, and the molar ratio of ethylene glycol to cellulose glucose unit is 1:5, and the mixture is washed with ethanol to a pH of 6-8, and freeze-dried to obtain the aldehyde-modified cellulose; the polyethylene glycol is PEG6000.

[0009] As an optimization, the preparation method of the maleic anhydride-esterified starch in step (4) is as follows: starch and maleic anhydride are added into a high-efficiency dry reactor in a mass ratio of 1:(1-2), reacted at 80°C for 3 hours, cooled to room temperature after the reaction, washed with acetone three times, and vacuum dried to obtain maleic anhydride-esterified starch; the dimethyl sulfoxide / 1-chloronaphthalene solution is obtained by mixing dimethyl sulfoxide and 1-chloronaphthalene in a volume ratio of 2:1, and the starch is corn starch.

[0010] As an optimization, the initiator in step (5) is ammonium persulfate.

[0011] Compared with the prior art, the present invention has the following beneficial effects: When preparing the composite sewage treatment agent, the present invention comprises the following steps: first, 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt is treated with thionyl chloride, and then reacted with hydrazine hydrate to obtain pyrenesulfonylhydrazide; oxidized cellulose, pyrenesulfonylhydrazide and polyethylene glycol are reacted to obtain porous cellulose; and then the cellulose is treated with maleic anhydride to obtain modified cellulose; secondly, maleic anhydride-esterified starch is reacted with 4-mercaptophthalonitrile, and then treated with ammonia gas, and then reacted with boron subphthalocyanine chloride to obtain modified starch; and finally, the modified cellulose, modified starch and an initiator are mixed and reacted to obtain the composite sewage treatment agent.

[0012] First, 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt is treated with thionyl chloride, and the sulfonic acid group is converted to sulfonyl chloride. The sulfonyl chloride reacts with hydrazine hydrate to obtain sulfonyl hydrazide groups. After cellulose is oxidized, the surface of the cellulose has aldehyde groups. The pyrenesulfonyl hydrazide containing sulfonyl hydrazide groups reacts with oxidized cellulose to form sulfonyl hydrazone bonds to cross-link the oxidized cellulose. During the cross-linking process, polyethylene glycol acts as a pore-forming agent to form porous cellulose. The formation of sulfonyl hydrazone bonds not only has good antibacterial properties, but also can better complex metal ions in wastewater. The conjugated plane of pyrene can adsorb small molecular pollutants containing aromatic structures through π-π stacking. The formation of a porous structure can provide a larger surface area, thereby enhancing the adsorption performance of the sewage treatment agent. After treatment with maleic anhydride, the modified cellulose has polymerizable double bond functional groups and carboxylic acid groups that can complex metal ions and adsorb positively charged pollutants. Secondly, maleic anhydride-esterified starch is reacted with 4-mercaptophthalonitrile, then treated with ammonia, and then reacted with boron subphthalocyanine chloride to obtain modified starch. The maleic anhydride-esterified starch provides the starch with polymerizable double bonds and carboxyl functional groups. The 4-mercaptophthalonitrile reacts with the double bonds and then is treated with ammonia to obtain a diimino-isoindoline structure. The diimino-isoindoline structure is then reacted with boron subphthalocyanine chloride to generate a phthalocyanine structure. The phthalocyanine structure not only has the ability to complex metals, but also has the ability to photocatalytically degrade organic matter after complexing metals, thereby further improving the water treatment capacity of the sewage treatment agent. Finally, the modified cellulose, modified starch and initiator are mixed to obtain a composite sewage treatment agent; cellulose and starch are derived from nature, are biodegradable and will not pollute the environment; the double bonds in the modified cellulose and the double bonds in the modified starch are polymerized under the action of the initiator to form a sewage treatment agent with a larger molecular weight, which makes the sewage treatment agent more stable and has broader application prospects and potential in the field of water treatment. DETAILED DESCRIPTION

[0013] 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.

[0014] In the following examples and comparative examples, the polyethylene glycol used is PEG6000; the dimethyl sulfoxide / 1-chloronaphthalene solution used is prepared by mixing dimethyl sulfoxide and 1-chloronaphthalene in a volume ratio of 2:1; the initiator used is ammonium persulfate; and the starch used is corn starch.

[0015] Example 1: A method for preparing a composite sewage treatment agent, comprising the following steps: (1) 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt, N,N-dimethylformamide, and 0.1 mol / L hydrogen chloride-ether solution were mixed in a mass ratio of 1:20:2. At 0°C, thionyl chloride in an amount 5 times the mass of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt was added and stirred for 4 hours. After the stirring was completed, an ice-water mixture in an amount 3 times the mass of N,N-dimethylformamide was added for precipitation. The mixture was filtered to obtain pyrenesulfonyl chloride. At 0°C, pyrenesulfonyl chloride, 85 wt% hydrazine hydrate solution, and tetrahydrofuran were mixed in a mass ratio of 1:0.4:15 for 5 minutes. After the mixture was heated to room temperature, the mixture was stirred for 3 hours. After the stirring was completed, an ice-water mixture in an amount 3 times the mass of tetrahydrofuran was added for precipitation. The mixture was filtered to obtain pyrenesulfonyl hydrazide. (2) Cellulose and acetic acid solution with a pH of 4.5 were mixed in a mass ratio of 1:20, sodium periodate was added, and the molar ratio of sodium periodate to cellulose glucose unit was 1.2:1. The mixture was reacted at 37°C in the dark for 4 hours. Ethylene glycol was added and stirred for 4 hours. The molar ratio of ethylene glycol to cellulose glucose unit was 1:5. The mixture was washed with ethanol until the pH was 8. The mixture was freeze-dried to obtain aldehyded cellulose. Aldehydated cellulose, polyethylene glycol, pure water, and tetrahydrofuran were mixed in a mass ratio of 1:0.05:5:10, heated to 45°C and stirred evenly. Pyrenesulfonylhydrazine (3 times the mass of the aldehyded cellulose) and lanthanum trifluoromethanesulfonate (0.02 times the mass of the aldehyded cellulose) were added and reacted for 2 hours. After the reaction, the mixture was cooled to room temperature, filtered, and immersed in pure water for 48 hours. The porous cellulose was then filtered and dried. (3) Porous cellulose and 15 wt% sodium hydroxide solution were mixed at a mass ratio of 1:20 for 30 min, filtered and washed with pure water 6 times, the washed porous cellulose and N,N-dimethylformamide were mixed at a mass ratio of 1:20 for 12 h, filtered to obtain activated porous cellulose, the activated porous cellulose, anhydrous lithium chloride and N,N-dimethylformamide were mixed at a mass ratio of 1:1:20, heated to 60 ° C and stirred for 10 min, maleic anhydride 0.5 times the mass of the activated porous cellulose was added, reacted at 60 ° C for 6 h, and freeze-dried after the reaction to obtain modified cellulose; (4) Starch and maleic anhydride were added to a high-efficiency dry reactor in a mass ratio of 1:1, reacted at 80°C for 3 hours, cooled to room temperature after the reaction, washed with acetone three times, and vacuum dried to obtain maleic anhydride-esterified starch; the dimethyl sulfoxide / 1-chloronaphthalene solution was obtained by mixing dimethyl sulfoxide and 1-chloronaphthalene in a volume ratio of 2:1; maleic anhydride-esterified starch, 4-mercaptophthalonitrile, azobisisobutyronitrile, and dimethyl sulfoxide were mixed in a mass ratio of 1:0.2:0.02:30, heated to 90°C under nitrogen protection for 4 hours, and cooled to room temperature after the reaction. , vacuum drying by vacuum rotary evaporation to obtain phthalonitrile starch; phthalonitrile starch and methanol are mixed in a mass ratio of 1:20, sodium 0.1 times the mass of phthalonitrile starch is added, ammonia is introduced at room temperature for 1 hour, the temperature is raised to 60°C, and ammonia is continued to react for 5 hours. After the reaction is completed, toluene is removed by vacuum rotary evaporation to obtain pre-modified starch; pre-modified starch, boron chloride subphthalocyanine, and dimethyl sulfoxide / 1-chloronaphthalene solution are mixed in a mass ratio of 1:0.5:30, heated to 90°C under nitrogen protection for 24 hours, and after the reaction is completed, modified starch is obtained by vacuum rotary evaporation; (5) Weigh the following raw materials: 10 parts by mass of modified cellulose, 5 parts by mass of modified starch, 0.3 parts by mass of initiator, and 50 parts by mass of pure water. Mix the modified cellulose and modified starch, add pure water and stir, then add the initiator and react at 80°C for 4 hours. Then, evaporate under reduced pressure to obtain a composite sewage treatment agent.

[0016] Example 2: A method for preparing a composite sewage treatment agent, comprising the following steps: (1) 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt, N,N-dimethylformamide, and 0.1 mol / L hydrogen chloride-ether solution were mixed in a mass ratio of 1:25:2.6. At 0°C, thionyl chloride in an amount 5.5 times the mass of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt was added and stirred for 3.5 hours. After the stirring was completed, an ice-water mixture in an amount 3.5 times the mass of N,N-dimethylformamide was added for precipitation. The mixture was filtered to obtain pyrenesulfonyl chloride. At -3°C, pyrenesulfonyl chloride, 85 wt% hydrazine hydrate solution, and tetrahydrofuran were mixed in a mass ratio of 1:0.5:17 for 4 minutes. After the mixture was heated to room temperature, the mixture was stirred for 3 hours. After the stirring was completed, an ice-water mixture in an amount 3.5 times the mass of tetrahydrofuran was added for precipitation. The mixture was filtered to obtain pyrenesulfonyl hydrazide. (2) Cellulose and acetic acid solution with a pH of 4.5 were mixed in a mass ratio of 1:20, sodium periodate was added, and the molar ratio of sodium periodate to cellulose glucose unit was 1.2:1. The mixture was reacted at 37°C in the dark for 4 hours, ethylene glycol was added and stirred for 4 hours, and the molar ratio of ethylene glycol to cellulose glucose unit was 1:5. The mixture was washed with ethanol until the pH was 7, and freeze-dried to obtain aldehyded cellulose; aldehyded cellulose, polyethylene glycol, pure water, and tetrahydrofuran were mixed in a mass ratio of 1:0.07:5.5:11, heated to 45°C and stirred evenly, 3.5 times the mass of aldehyded cellulose of pyrenesulfonylhydrazine and 0.025 times the mass of aldehyded cellulose of lanthanum trifluoromethanesulfonate were added and reacted for 1.5 hours. After the reaction, the mixture was cooled to room temperature, filtered, and immersed in pure water for 48 hours. The porous cellulose was then filtered and dried to obtain the porous cellulose; (3) Porous cellulose and 15 wt% sodium hydroxide solution were mixed at a mass ratio of 1:20 for 30 min, filtered and washed with pure water 6 times, the washed porous cellulose and N,N-dimethylformamide were mixed at a mass ratio of 1:20 for 12 h, filtered to obtain activated porous cellulose, the activated porous cellulose, anhydrous lithium chloride and N,N-dimethylformamide were mixed at a mass ratio of 1:1.5:25, heated to 55 ° C and stirred for 7 min, maleic anhydride 0.6 times the mass of the activated porous cellulose was added, reacted at 55 ° C for 5.5 h, and freeze-dried after the reaction to obtain modified cellulose; (4) Starch and maleic anhydride were added into a high-efficiency dry reactor in a mass ratio of 1:1.5, and reacted at 80°C for 3 hours. After the reaction, the mixture was cooled to room temperature, washed with acetone for 3 times, and vacuum dried to obtain maleic anhydride-esterified starch. Maleic anhydride-esterified starch, 4-mercaptophthalonitrile, azobisisobutyronitrile, and dimethyl sulfoxide were mixed in a mass ratio of 1:0.25:0.026:37, heated to 90°C under nitrogen protection, and reacted for 3.5 hours. After the reaction, the mixture was cooled to room temperature, and vacuum dried by rotary evaporation to obtain phthalonitrile. Nitrile starch; phthalonitrile starch and methanol are mixed in a mass ratio of 1:25, sodium is added in an amount 0.1 times the mass of phthalonitrile starch, ammonia gas is introduced at room temperature for 1 hour, the temperature is raised to 60°C, ammonia gas is continued to react for 5 hours, and after the reaction is completed, toluene is removed by vacuum rotary evaporation to obtain pre-modified starch; pre-modified starch, boron chloride subphthalocyanine, and dimethyl sulfoxide / 1-chloronaphthalene solution are mixed in a mass ratio of 1:0.6:35, heated to 85°C under nitrogen protection, and reacted for 24 hours. After the reaction is completed, vacuum rotary evaporation is performed to obtain modified starch; (5) Weigh the following raw materials: 13 parts of modified cellulose, 7 parts of modified starch, 0.4 parts of initiator, and 60 parts of pure water, by mass. Mix the modified cellulose and modified starch, add pure water and stir, then add the initiator and react at 75°C for 3 hours. Then, evaporate under reduced pressure to obtain a composite sewage treatment agent.

[0017] Example 3: A method for preparing a composite sewage treatment agent, comprising the following steps: (1) 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt, N,N-dimethylformamide, and 0.1 mol / L hydrogen chloride-ether solution were mixed in a mass ratio of 1:30:3. At 0°C, thionyl chloride in an amount 5-6 times the mass of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt was added and stirred for 3 hours. After the stirring was completed, an ice-water mixture in an amount 4 times the mass of N,N-dimethylformamide was added for precipitation. The mixture was filtered to obtain pyrenesulfonyl chloride. At -5°C, pyrenesulfonyl chloride, 85wt% hydrazine hydrate solution, and tetrahydrofuran were mixed in a mass ratio of 1:0.6:20 for 3 minutes. After the temperature was raised to room temperature, the mixture was stirred for 3 hours. After the stirring was completed, an ice-water mixture in an amount 4 times the mass of tetrahydrofuran was added for precipitation. The mixture was filtered to obtain pyrenesulfonyl hydrazide. (2) Cellulose and acetic acid solution with a pH of 4.5 were mixed in a mass ratio of 1:20, sodium periodate was added, and the molar ratio of sodium periodate to cellulose glucose unit was 1.2:1. The mixture was reacted at 37°C in the dark for 4 hours. Ethylene glycol was added and stirred for 4 hours. The molar ratio of ethylene glycol to cellulose glucose unit was 1:5. The mixture was washed with ethanol until the pH was 6. The mixture was freeze-dried to obtain aldehyded cellulose. Aldehydated cellulose, polyethylene glycol, pure water, and tetrahydrofuran were mixed in a mass ratio of 1:0.1:6:12. The mixture was heated to 45°C and stirred evenly. Pyrenesulfonylhydrazine (4 times the mass of the aldehyded cellulose) and lanthanum trifluoromethanesulfonate (0.03 times the mass of the aldehyded cellulose) were added and reacted for 1 hour. After the reaction, the mixture was cooled to room temperature, filtered, and immersed in pure water for 48 hours. The porous cellulose was then filtered and dried. (3) Porous cellulose and 15 wt% sodium hydroxide solution were mixed at a mass ratio of 1:20 for 30 min, filtered and washed with pure water 6 times, the washed porous cellulose and N,N-dimethylformamide were mixed at a mass ratio of 1:20 for 12 h, filtered to obtain activated porous cellulose, the activated porous cellulose, anhydrous lithium chloride and N,N-dimethylformamide were mixed at a mass ratio of 1:2:30, heated to 50 ° C and stirred for 5 min, maleic anhydride 0.7 times the mass of the activated porous cellulose was added, reacted at 50 ° C for 5 h, and freeze-dried after the reaction to obtain modified cellulose; (4) Starch and maleic anhydride were added to a high-efficiency dry reactor in a mass ratio of 1:2, and reacted at 80°C for 3 hours. After the reaction, the mixture was cooled to room temperature, washed with acetone three times, and vacuum dried to obtain maleic anhydride-esterified starch; the dimethyl sulfoxide / 1-chloronaphthalene solution was obtained by mixing dimethyl sulfoxide and 1-chloronaphthalene in a volume ratio of 2:1; maleic anhydride-esterified starch, 4-mercaptophthalonitrile, azobisisobutyronitrile, and dimethyl sulfoxide were mixed in a mass ratio of 1:0.3:0.03:40, heated to 90°C under nitrogen protection for 3 hours, and cooled to room temperature after the reaction. , vacuum drying by rotary evaporation to obtain phthalonitrile starch; mixing phthalonitrile starch and methanol in a mass ratio of 1:30, adding sodium 0.1 times the mass of phthalonitrile starch, passing ammonia gas at room temperature for 1 hour, heating to 60°C, continuing to pass ammonia gas for 5 hours, and after the reaction is completed, removing toluene by rotary evaporation to obtain pre-modified starch; mixing pre-modified starch, boron chloride subphthalocyanine, and dimethyl sulfoxide / 1-chloronaphthalene solution in a mass ratio of 1:0.7:40, heating to 80°C under nitrogen protection for 24 hours, and after the reaction is completed, rotary evaporation to obtain modified starch; (5) Weigh the following raw materials: 15 parts of modified cellulose, 10 parts of modified starch, 0.5 parts of initiator, and 70 parts of pure water, by mass. Mix the modified cellulose and modified starch, add pure water and stir, then add the initiator and react at 70°C for 2 hours. Then, evaporate under reduced pressure to obtain a composite sewage treatment agent.

[0018] Comparative Example 1: The preparation method of the composite sewage treatment agent of Comparative Example 1 differs from that of Example 2 in that step (1) is not included, and step (2) is modified as follows: cellulose and acetic acid solution with a pH of 4.5 are mixed in a mass ratio of 1:20, sodium periodate is added, and the molar ratio of sodium periodate to cellulose glucose unit is 1.2:1, and the mixture is reacted at 37°C in the dark for 4 hours, ethylene glycol is added and stirred for 4 hours, and the molar ratio of ethylene glycol to cellulose glucose unit is 1:5, and ethanol is used to wash the mixture until the pH is 7, and the mixture is freeze-dried to obtain formaldehyded cellulose; formaldehyded cellulose, polyethylene glycol, pure water, and tetrahydrofuran are mixed in a mass ratio of 1:0.07:5.5:11, heated to 45°C, and stirred evenly. After the reaction is completed, the mixture is cooled to room temperature, filtered, and immersed in pure water for 48 hours, and then filtered and dried to obtain porous cellulose.

[0019] Comparative Example 2: The preparation method of the composite sewage treatment agent of Comparative Example 2 differs from that of Example 2 in that step (4) is modified as follows: starch and maleic anhydride are added to a high-efficiency dry reactor in a mass ratio of 1:1.5, reacted at 80°C for 3h, cooled to room temperature after the reaction, washed with acetone 3 times, and vacuum dried to obtain maleic anhydride-esterified starch; maleic anhydride-esterified starch, 4-mercaptophthalonitrile, azobisisobutyronitrile, and dimethyl sulfoxide are mixed in a mass ratio of 1:0.25:0.026:37, heated to 90°C under nitrogen protection, reacted for 3.5h, cooled to room temperature after the reaction, and vacuum dried by rotary evaporation to obtain phthalonitrile starch; phthalonitrile starch and methanol are mixed in a mass ratio of 1:25, sodium 0.1 times the mass of phthalonitrile starch is added, ammonia is introduced at room temperature for 1h, heated to 60°C, and ammonia is continued to be introduced for 5h. After the reaction is completed, toluene is removed by rotary evaporation to obtain modified starch.

[0020] Test Example 1, Antibacterial Performance Test: Test method: The antibacterial rate of the composite sewage treatment agent prepared in the embodiment and the comparative example was tested according to the standard WS / T 650-2019. The results are shown in Table 1: From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 2 in Table 1, it can be found that the water treatment filter material prepared by the present invention has good antibacterial properties.

[0021] By comparison, the antibacterial rates of Examples 1 to 3 are greater than that of Comparative Example 1, indicating that after 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt is treated with thionyl chloride, the sulfonic acid group is sulfonyl chloride, and the sulfonyl chloride reacts with hydrazine hydrate to obtain a sulfonylhydrazine group; after oxidation, cellulose has an aldehyde group on its surface, and the pyrenesulfonylhydrazine containing the sulfonylhydrazine group reacts with the oxidized cellulose to cross-link the oxidized cellulose by forming a sulfonylhydrazone bond, and the formation of the sulfonylhydrazone bond has good antibacterial properties.

[0022] Test Example 2, adsorption performance test: Copper sulfate pentahydrate was prepared into a 40 mg / L copper ion solution. The wastewater treatment agents prepared in the Examples and Comparative Examples were mixed with the copper ion solution at a mass-to-volume ratio of 10 g:1 L. The mixture was shaken at 120 rpm / min at 30°C for 90 minutes and then allowed to stand for 60 minutes. The copper ion content in the supernatant was determined by flame atomic absorption spectrometry, and the copper ion removal rate was calculated. The results are shown in Table 2.

[0023] Photocatalytic degradation performance test: Copper sulfate pentahydrate is configured to a copper ion solution of 40mg / L, and then a methyl orange solution of 40mg / L is prepared; the sewage treatment agent, copper ion solution, and methyl orange solution obtained in the embodiment and comparative example are mixed in a mass volume ratio of 10g:1L:1L, ultrasonically treated for 30min to make them uniformly mixed, placed in a photochemical reactor and stirred in the dark for 90min, allowed to stand for 60min, the supernatant methyl orange concentration was measured, and then the light source was turned on for photocatalytic reaction, the stirring reaction time was 60min, the light source was a 300W xenon lamp, the xenon lamp emission wavelength range was 360-780nm, the light source was 10cm away, and then allowed to stand for 60min, the supernatant was collected, the methyl orange concentration was determined by spectrophotometry, and the degradation rate of methyl orange was calculated. The results are shown in Table 2: From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 2 in Table 2, it can be found that the sewage treatment agent prepared by the present invention has good adsorption and photocatalytic degradation properties.

[0024] By comparison, the copper ion removal rates of Examples 1 to 3 are greater than those of Comparative Examples 1 to 2, and the degradation rates of Examples 1 to 3 are greater than those of Comparative Example 2, indicating that after 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt is treated with thionyl chloride, the sulfonic acid group is converted to sulfonyl chloride, and the sulfonyl chloride reacts with hydrazine hydrate to obtain a sulfonylhydrazine group; after oxidation, the cellulose surface carries aldehyde groups, and the pyrenesulfonylhydrazine containing sulfonylhydrazine groups reacts with the oxidized cellulose to form sulfonylhydrazone bonds to cross-link the oxidized cellulose. During the cross-linking process, polyethylene glycol acts as a porogen to form porous cellulose. The formation of sulfonylhydrazone bonds not only has good antibacterial properties, but also can better complex metal ions in sewage. The formation of a porous structure can provide a larger surface area, thereby enhancing the adsorption performance of the sewage treatment agent; Secondly, maleic anhydride-esterified starch is reacted with 4-mercaptophthalonitrile, then treated with ammonia, and then reacted with boron subphthalocyanine chloride to obtain modified starch; the maleic anhydride-esterified starch allows the starch to have polymerizable double bonds and carboxyl functional groups, 4-mercaptophthalonitrile reacts with the double bonds, and then treated with ammonia to obtain a diimino-isoindoline structure, which then reacts with boron subphthalocyanine chloride to generate a phthalocyanine structure. The phthalocyanine structure not only has the ability to complex metals, but also has the ability to photocatalytically degrade organic matter after complexing metals, which can further improve the water treatment capacity of the sewage treatment agent.

[0025] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be encompassed therein. Any reference in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A composite sewage treatment agent, characterized in that: The composite sewage treatment agent is obtained by a mixed reaction of modified cellulose, modified starch and an initiator; The modified cellulose is a porous cellulose obtained by reacting oxidized cellulose, pyrenesulfonylhydrazine, and polyethylene glycol, and then treated with maleic anhydride; the pyrenesulfonylhydrazine is obtained by treating 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt with thionyl chloride and reacting with hydrazine hydrate; The modified starch is obtained by reacting maleic anhydride esterified starch with 4-mercaptophthalonitrile, treating with ammonia gas, and reacting with boron chloride subphthalocyanine.

2. A method for preparing a composite sewage treatment agent, characterized in that: The method comprises the following preparation steps: (1) 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt, N,N-dimethylformamide, and 0.1 mol / L hydrogen chloride-ether solution are mixed in a mass ratio of 1:(20-30):(2-3). At 0°C, thionyl chloride in an amount 5-6 times the mass of 1,3,6,8-pyrenetetrasulfonic acid tetrasodium salt is added and stirred for 3-4 hours. After the stirring is completed, an ice-water mixture in an amount 3-4 times the mass of N,N-dimethylformamide is added for precipitation, and pyrenesulfonyl chloride is obtained by suction filtration. At -5-0°C, pyrenesulfonyl chloride, 85wt% hydrazine hydrate solution, and tetrahydrofuran are mixed in a mass ratio of 1:(0.4-0.6):(15-20) for 3-5 minutes. After the temperature is raised to room temperature, stirring is continued for 3 hours. After the stirring is completed, an ice-water mixture in an amount 3-4 times the mass of tetrahydrofuran is added for precipitation, and pyrenesulfonyl hydrazide is obtained by suction filtration. (2) Mix aldehyde-modified cellulose, polyethylene glycol, pure water, and tetrahydrofuran in a mass ratio of 1:(0.05-0.1):(5-6):(10-12), heat to 45°C and stir evenly, add 3-4 times the mass of aldehyde-modified cellulose pyrenesulfonylhydrazine and 0.02-0.03 times the mass of aldehyde-modified cellulose lanthanum trifluoromethanesulfonate and react for 1-2 hours. After the reaction, cool to room temperature, filter and immerse in pure water for 48 hours, and then filter and dry to obtain porous cellulose; (3) Porous cellulose and 15 wt% sodium hydroxide solution were mixed at a mass ratio of 1:20 for 30 minutes, filtered and washed with pure water for 6 times, the washed porous cellulose and N,N-dimethylformamide were mixed at a mass ratio of 1:20 for 12 hours, filtered to obtain activated porous cellulose, the activated porous cellulose, anhydrous lithium chloride, and N,N-dimethylformamide were mixed at a mass ratio of 1:(1-2):(20-30), heated to 50-60 ° C and stirred for 5-10 minutes, maleic anhydride 0.5-0.7 times the mass of the activated porous cellulose was added, reacted at 50-60 ° C for 5-6 hours, and freeze-dried after the reaction to obtain modified cellulose; (4) Maleic anhydride esterified starch, 4-mercaptophthalonitrile, azobisisobutyronitrile and dimethyl sulfoxide were mixed in a mass ratio of 1: (0.2-0.3): (0.02-0.03): (30-40), heated to 90 ° C under nitrogen protection for 3-4 hours, cooled to room temperature after the reaction, and vacuum dried by rotary evaporation to obtain phthalonitrile starch; phthalonitrile starch and methanol were mixed in a mass ratio of 1: (20-30), and phthalonitrile was added. Ammonia gas is introduced into a mixture of 0.1 times the mass of sodium cyanide starch at room temperature for 1 hour, the temperature is raised to 60°C, and the ammonia gas is continued to react for 5 hours. After the reaction is completed, the toluene is removed by vacuum rotary evaporation to obtain pre-modified starch; the pre-modified starch, boron chloride subphthalocyanine, and dimethyl sulfoxide / 1-chloronaphthalene solution are mixed in a mass ratio of 1:(0.5-0.7):(30-40), heated to 80-90°C under nitrogen protection, and reacted for 24 hours. After the reaction is completed, the modified starch is obtained by vacuum rotary evaporation; (5) Weigh the following raw materials: 10-15 parts by mass of modified cellulose, 5-10 parts by mass of modified starch, 0.3-0.5 parts by mass of initiator, and 50-70 parts by mass of pure water. Mix the modified cellulose and modified starch, add pure water and stir, then add the initiator and react at 70-80°C for 2-4 hours. Then, evaporate under reduced pressure to obtain a composite sewage treatment agent.

3. The method for preparing a composite sewage treatment agent according to claim 2, wherein: The preparation method of the aldehyded cellulose in step (2) is as follows: cellulose and an acetic acid solution with a pH of 4.5 are mixed in a mass ratio of 1:20, sodium periodate is added, and the molar ratio of sodium periodate to cellulose glucose unit is 1.2:1, and the mixture is reacted at 37°C in the dark for 4 hours, ethylene glycol is added and stirred for 4 hours, and the molar ratio of ethylene glycol to cellulose glucose unit is 1:5, and the mixture is washed with ethanol to a pH of 6-8, and freeze-dried to obtain the aldehyded cellulose; the polyethylene glycol is PEG6000.

4. The method for preparing a composite sewage treatment agent according to claim 2, characterized in that: The preparation method of the maleic anhydride-esterified starch in step (4) is as follows: starch and maleic anhydride are added into a high-efficiency dry reactor in a mass ratio of 1:(1-2), reacted at 80° C. for 3 hours, cooled to room temperature after the reaction, washed with acetone three times, and vacuum-dried to obtain the maleic anhydride-esterified starch; the dimethyl sulfoxide / 1-chloronaphthalene solution is obtained by mixing dimethyl sulfoxide and 1-chloronaphthalene in a volume ratio of 2:1; and the starch is corn starch.

5. The method for preparing a composite sewage treatment agent according to claim 2, characterized in that: The initiator in step (5) is ammonium persulfate.

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