A method for preparing reclaimed water based on non-complex state manganese oxidation technology

Abstract

The application discloses a kind of based on non-complex state manganese oxidation technology's reclaimed water preparation method, it is related to reclaimed water preparation technical field, including following material: phosphate buffer, potassium permanganate, ferrous sulfide, modified chitosan, modified polyaspartic acid, glutamic acid diacetic acid tetrasodium;The application maintains water quality alkaline environment by adding phosphate buffer, greatly inhibits the risk of toxic gas generated by ferrous sulfide hydrolysis, guarantees the safety of preparation process;The modified chitosan added, by electric neutralization and adsorption bridging, small precipitate is quickly flocculated into sedimentable alum flower, realizes mud-water separation;By adding modified polyaspartic acid, can prevent the scale formed by precipitation in irrigation pipeline or equipment, and glutamic acid diacetic acid tetrasodium synergistic effect, jointly ensure the chemical stability of reclaimed water in storage and conveying process, protect irrigation system, water quality long-term stability.

Description

Technical Field

[0001] This invention relates to the field of reclaimed water preparation technology, and in particular to a method for preparing reclaimed water based on non-complexed manganese oxidation technology. Background Technology

[0002] Reclaimed water refers to wastewater that has been treated using appropriate recycling processes to meet certain water quality requirements and functional needs, making it suitable for beneficial use. Compared to developing new water resources, reclaimed water utilization has significant advantages, including not impacting the ecological environment, not competing for water resources, not requiring dam construction, not flooding land, not needing long-distance water transportation, lower investment, faster results, and lower costs. It not only helps optimize the water supply structure, increase water resource supply, and alleviate supply-demand imbalances, but also reduces water pollution and ensures water ecological security. Therefore, it is of great significance for promoting ecological civilization, achieving high-quality development, and meeting the people's growing needs for a better life.

[0003] The main drawbacks of existing non-complexed manganese oxidation technology for reclaimed water production are that its effectiveness is highly sensitive to operating conditions and poses a risk of secondary pollution. The technology exhibits extremely slow natural oxidation rates under neutral pH conditions, requiring the pH to be raised above 9.0 or relying on strong oxidants to ensure efficiency, resulting in high energy consumption and reagent costs. Fluctuations in influent water quality (such as interference from coexisting reducing substances like iron and organic matter) or changes in hydraulic conditions can easily lead to unstable treatment results. More importantly, during the reaction process, excessive manganese ion release may occur due to filter media corrosion or improper control. Furthermore, the use of oxidants such as chloramines, if not properly controlled, can produce harmful disinfection byproducts, increasing environmental and health risks.

[0004] Therefore, a method for preparing reclaimed water based on non-complexed manganese oxidation technology is proposed to solve the above problems. Summary of the Invention

[0005] The main objective of this invention is to provide a method for preparing reclaimed water with low heavy metal content and low impurities.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a method for preparing reclaimed water based on non-complexed manganese oxidation technology, wherein the method for preparing reclaimed water based on non-complexed manganese oxidation technology includes the following steps:

[0007] S1. Add some deionized water to a magnetic reactor and stir at 400-600 rpm. Add modified chitosan and stir for 30-60 minutes. Add the remaining deionized water to obtain a modified chitosan solution.

[0008] S2. Take 1L of wastewater and place it in a reaction vessel and stir at 150-250 rpm. Add phosphate buffer and stir at 150-250 rpm for 10-20 minutes. Add pH adjuster dropwise to obtain an alkaline water sample.

[0009] S3. Add potassium permanganate to the alkaline water sample and stir at 150-250 rpm for 30 minutes. Add ferrous sulfide and stir at 300-400 rpm for 2 minutes. Adjust the speed to 150-250 rpm and stir for 40 minutes. Add modified chitosan solution and stir at 120-180 rpm for 1 minute. Adjust the speed to 40-60 rpm and stir for 20-30 minutes. Let stand for 90-120 minutes. Transfer the supernatant to a new reactor. Add modified polyaspartic acid to the new reactor and stir at 80-120 rpm for 5-10 minutes. Add tetrasodium diacetate of glutamic acid and stir for 5-10 minutes to obtain clean water.

[0010] S4. Disinfect the clean water using an ultraviolet sterilizer for 30 minutes to obtain reclaimed water.

[0011] 1L of wastewater needs to be screened to remove large particles of debris.

[0012] Further, the mass ratio of the phosphate buffer, potassium permanganate, ferrous sulfide, modified chitosan, modified polyaspartic acid, tetrasodium diacetate of glutamic acid, and 1L of wastewater is 0.002-0.005: 0.0001-0.0005: 0.001-0.003: 0.0005-0.0015: 0.001-0.003: 0.0005-0.0015: 1.

[0013] Furthermore, the mass ratio of the S1 modified chitosan to a portion of the deionized water is 1:190;

[0014] The mass ratio of the modified chitosan to the remaining deionized water is 1:9.

[0015] Furthermore, the pH adjuster is either a hydrogen chloride solution or a sodium hydroxide solution. The pH is adjusted to 7.5-8.5 by adding the pH adjuster dropwise.

[0016] Furthermore, the phosphate buffer is a mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate;

[0017] The mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate is 1:2.5.

[0018] Further, the modified chitosan is prepared by the following steps: Deionized water and chitosan are added to a reaction vessel and stirred at 300-400 rpm for 30-40 minutes; dilute acetic acid is added and stirred at 200-300 rpm for 5-10 minutes; 2,3-epoxypropyltrimethylammonium chloride solution is added and stirred at 200-400 rpm for 2-4 hours; sodium hydroxide solution is added and stirred at 60-70℃ for 4-8 hours to obtain a reaction solution; the reaction solution is poured into anhydrous ethanol and stirred at 300-400 rpm for 5-10 minutes; the supernatant is filtered off, and the filter residue is collected; the filter residue is washed 3-5 times with ethanol and 1-2 times with acetone; the washed filter residue is placed in a vacuum drying oven and dried at 40-50℃ for 12-24 hours. Quaternized chitosan was prepared by adding deionized water to a reaction vessel and stirring at 200-400 rpm for 10-20 minutes to obtain a quaternized chitosan solution. N,N-dimethylformamide was added to a water bath reaction vessel at 0-5℃, and the quaternized chitosan solution was added and stirred at 400-600 rpm. Succinic anhydride was added and stirred at 10-20℃ for 2-4 hours. The stirring speed was then increased to 300-500 rpm and the temperature was controlled at 18-25℃ for another 2-4 hours to obtain a reaction solution. The reaction solution was placed in a dialysis bag and dialyzed with deionized water for 2-3 days, changing the water 4-5 times a day. The dialyzed reaction solution was then placed in a vacuum drying oven at 40-50℃ for 24-48 hours to obtain modified chitosan.

[0019] Furthermore, the mass ratio of the deionized water to chitosan is 30-40:1;

[0020] The pH value is adjusted to 5-6 by adding dilute acetic acid;

[0021] The sodium hydroxide solution has a concentration of 1% and the pH value is adjusted to 7-9.

[0022] The mass concentration of the 2,3-epoxypropyltrimethylammonium chloride solution is 60%; the molar ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:1.2-1.5.

[0023] Furthermore, the molar ratio of succinic anhydride to quaternized chitosan is 1-2:1;

[0024] The mass ratio of N,N-dimethylformamide to quaternized chitosan is 10-20:1;

[0025] The dialysis bag has a molecular weight cutoff of 3500 Da.

[0026] Further, the modified polyaspartic acid is prepared by the following steps: maleic anhydride and deionized water are added to a reaction vessel and stirred; ammonia, aminomethylphosphonic acid, and phosphoric acid are added and stirred; the temperature is controlled at 80-90℃, the stirring speed is 200-400 rpm, and the stirring time is 30-60 minutes; the stirring speed is adjusted to 150-300 rpm, and the temperature is heated to 180-240℃ at a rate of 1-3℃ / minute; the stirring speed is adjusted to 80-150 rpm, and the stirring time is 1-3 hours to obtain a polysuccinimide intermediate; sodium hydroxide solution is added to the reaction vessel and stirred; the temperature is... The temperature is controlled at 70-80℃, the stirring speed is 200-400rpm, and the stirring time is 1-1.5 hours. The temperature of the reaction vessel is cooled to 18-25℃ to obtain polysuccinimide intermediate liquid. The polysuccinimide intermediate liquid is poured into anhydrous ethanol and stirred at 80-150rpm for 10-15 minutes. The liquid is filtered off to obtain filter cake. The filter cake is washed with anhydrous ethanol 3-5 times. The washed filter cake is placed in a vacuum drying oven and dried at 40-60℃ for 24-48 hours to obtain modified polyaspartic acid.

[0027] Furthermore, the mass ratio of maleic anhydride to deionized water is 1:1.5-3;

[0028] The mass ratio of maleic anhydride, ammonia, and aminomethylphosphonic acid is 1:1.6:0.11;

[0029] The mass ratio of the total mass of phosphoric acid to maleic anhydride, ammonia, and aminomethylphosphonic acid is 0.025:1.

[0030] The concentration of ammonia water is 25%-28% (w / w);

[0031] The molar ratio of the sodium hydroxide solution to the polysuccinimide intermediate is 2:1.

[0032] The present invention has the following beneficial effects:

[0033] 1. In this invention, by adding a phosphate buffer, the water quality is maintained in an alkaline environment, which greatly suppresses the risk of ferrous sulfide hydrolysis producing highly toxic gases and ensures the safety of the preparation. Ferrous sulfide can work synergistically with potassium permanganate to greatly enhance the removal efficiency of heavy metals. Ferrous sulfide can also work synergistically with modified chitosan. Ferrous sulfide produces fine precipitates, while modified chitosan can efficiently aggregate them into large flocs, greatly accelerating the settling speed, greatly shortening the treatment time, and improving the clarity of the effluent.

[0034] 2. In this invention, the added modified chitosan, through charge neutralization and adsorption bridging, rapidly flocculates tiny precipitates into settleable flocs, achieving mud-water separation; the temporal synergistic effect of modified chitosan and tetrasodium glutamate diacetate, after the modified chitosan flocculates, allows tetrasodium glutamate diacetate to complex trace amounts of residual heavy metals that cannot be precipitated, solving the "tailing" problem of traditional precipitation methods and ensuring that the heavy metal indicators of the effluent consistently meet the standards.

[0035] 3. In this invention, by adding modified polyaspartic acid, the functional groups such as carboxyl groups in its molecule can be used to disperse scale-forming ions such as calcium and magnesium in the water, preventing them from precipitating and forming scale in irrigation pipes or equipment; it can also work synergistically with tetrasodium glutamate diacetate, with modified polyaspartic acid preventing inorganic scaling and tetrasodium glutamate diacetate preventing heavy metal precipitation, together ensuring the chemical stability of reclaimed water during storage and transportation, protecting the irrigation system, and ensuring long-term stable water quality. Detailed Implementation

[0036] 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.

[0037] It should be noted that all raw materials used in the following experiments are commercially available.

[0038] Example 1: A method for preparing reclaimed water based on non-complexed manganese oxidation technology, comprising the following steps:

[0039] S1. Add some deionized water to a magnetic reactor and stir at 400-600 rpm. Add modified chitosan and stir for 30-60 minutes. Add the remaining deionized water to obtain a modified chitosan solution.

[0040] S2. Take 1L of wastewater and place it in a reaction vessel and stir at 150-250 rpm. Add phosphate buffer and stir at 150-250 rpm for 10-20 minutes. Add pH adjuster dropwise to obtain an alkaline water sample.

[0041] S3. Add potassium permanganate to the alkaline water sample and stir at 150-250 rpm for 30 minutes. Add ferrous sulfide and stir at 300-400 rpm for 2 minutes. Adjust the speed to 150-250 rpm and stir for 40 minutes. Add modified chitosan solution and stir at 120-180 rpm for 1 minute. Adjust the speed to 40-60 rpm and stir for 20-30 minutes. Let stand for 90-120 minutes. Transfer the supernatant to a new reactor. Add modified polyaspartic acid to the new reactor and stir at 80-120 rpm for 5-10 minutes. Add tetrasodium diacetate of glutamic acid and stir for 5-10 minutes to obtain clean water.

[0042] S4. Disinfect the clean water using an ultraviolet sterilizer for 30 minutes to obtain reclaimed water.

[0043] The mass ratio of the phosphate buffer, potassium permanganate, ferrous sulfide, modified chitosan, modified polyaspartic acid, tetrasodium diacetate of glutamic acid, and 1L of wastewater is 0.002:0.0001:0.001:0.0005:0.001:0.0005:1.

[0044] The mass ratio of the S1 modified chitosan to part of the deionized water is 1:190;

[0045] The mass ratio of the modified chitosan to the remaining deionized water is 1:9.

[0046] The pH adjuster is either a hydrogen chloride solution or a sodium hydroxide solution. The pH is adjusted to 7.5-8.5 by adding the pH adjuster dropwise.

[0047] The phosphate buffer is a mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate;

[0048] The mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate is 1:2.5.

[0049] The modified chitosan was prepared through the following steps: Deionized water and chitosan were added to a reaction vessel and stirred at 300-400 rpm for 30-40 minutes. Dilute acetic acid was added and stirred at 200-300 rpm for 5-10 minutes. 2,3-epoxypropyltrimethylammonium chloride solution was added and stirred at 200-400 rpm for 2-4 hours. Sodium hydroxide solution was added and stirred at 60-70℃ for 4-8 hours to obtain a reaction solution. The reaction solution was poured into anhydrous ethanol and stirred at 300-400 rpm for 5-10 minutes. The supernatant was filtered off, and the filter residue was collected. The filter residue was washed 3-5 times with ethanol and 1-2 times with acetone. The washed filter residue was placed in a vacuum drying oven and dried at 40-50℃ for 12-24 hours. To prepare quaternized chitosan, deionized water was added to a reaction vessel and stirred at 200-400 rpm. Quaternized chitosan was then added and stirred for 10-20 minutes to obtain a quaternized chitosan solution. N,N-dimethylformamide was added to a water bath reaction vessel, and the water bath temperature was controlled at 0-5℃. The quaternized chitosan solution was added and stirred at 400-600 rpm. Succinic anhydride was added and stirred at 10-20℃ for 2-4 hours. The stirring speed was then adjusted to 300-500 rpm, and the temperature was controlled at 18-25℃ for 2-4 hours to obtain a reaction solution. The reaction solution was placed in a dialysis bag and dialyzed with deionized water for 2-3 days, changing the water 4-5 times a day. The dialyzed reaction solution was then placed in a vacuum drying oven and dried at 40-50℃ for 24-48 hours to obtain modified chitosan.

[0050] The mass ratio of deionized water to chitosan is 30-40:1;

[0051] The pH value is adjusted to 5-6 by adding dilute acetic acid;

[0052] The sodium hydroxide solution has a concentration of 1% and the pH value is adjusted to 7-9.

[0053] The mass concentration of the 2,3-epoxypropyltrimethylammonium chloride solution is 60%; the molar ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:1.2-1.5.

[0054] The molar ratio of succinic anhydride to quaternized chitosan is 1-2:1;

[0055] The mass ratio of N,N-dimethylformamide to quaternized chitosan is 10-20:1;

[0056] The dialysis bag has a molecular weight cutoff of 3500 Da.

[0057] The modified polyaspartic acid is prepared through the following steps: maleic anhydride and deionized water are added to a reaction vessel and stirred. Ammonia, aminomethylphosphonic acid, and phosphoric acid are added and stirred. The temperature is controlled at 80-90℃, the stirring speed is 200-400 rpm, and the stirring time is 30-60 minutes. The stirring speed is then adjusted to 150-300 rpm, and the temperature is heated to 180-240℃ at a rate of 1-3℃ / minute. The stirring speed is then adjusted to 80-150 rpm, and the stirring time is 1-3 hours to obtain a polysuccinimide intermediate. Sodium hydroxide solution is added to the reaction vessel and stirred. The temperature is controlled at... The mixture is stirred at 70-80℃ and 200-400 rpm for 1-1.5 hours. The reactor temperature is then cooled to 18-25℃ to obtain a polysuccinimide intermediate liquid. This liquid is then poured into anhydrous ethanol and stirred at 80-150 rpm for 10-15 minutes. The liquid is then filtered off to obtain a filter cake. The filter cake is washed with anhydrous ethanol 3-5 times. The washed filter cake is then placed in a vacuum drying oven and dried at 40-60℃ for 24-48 hours to obtain modified polyaspartic acid.

[0058] The mass ratio of maleic anhydride to deionized water is 1:1.5-3;

[0059] The mass ratio of maleic anhydride, ammonia, and aminomethylphosphonic acid is 1:1.6:0.11;

[0060] The mass ratio of the total mass of phosphoric acid to maleic anhydride, ammonia, and aminomethylphosphonic acid is 0.025:1.

[0061] The concentration of ammonia water is 25%-28% (w / w);

[0062] The molar ratio of the sodium hydroxide solution to the polysuccinimide intermediate is 2:1.

[0063] Example 2: A method for preparing reclaimed water based on non-complexed manganese oxidation technology, comprising the following steps:

[0064] S1. Add some deionized water to a magnetic reactor and stir at 400-600 rpm. Add modified chitosan and stir for 30-60 minutes. Add the remaining deionized water to obtain a modified chitosan solution.

[0065] S2. Take 1L of wastewater and place it in a reaction vessel and stir at 150-250 rpm. Add phosphate buffer and stir at 150-250 rpm for 10-20 minutes. Add pH adjuster dropwise to obtain an alkaline water sample.

[0066] S3. Add potassium permanganate to the alkaline water sample and stir at 150-250 rpm for 30 minutes. Add ferrous sulfide and stir at 300-400 rpm for 2 minutes. Adjust the speed to 150-250 rpm and stir for 40 minutes. Add modified chitosan solution and stir at 120-180 rpm for 1 minute. Adjust the speed to 40-60 rpm and stir for 20-30 minutes. Let stand for 90-120 minutes. Transfer the supernatant to a new reactor. Add modified polyaspartic acid to the new reactor and stir at 80-120 rpm for 5-10 minutes. Add tetrasodium diacetate of glutamic acid and stir for 5-10 minutes to obtain clean water.

[0067] S4. Disinfect the clean water using an ultraviolet sterilizer for 30 minutes to obtain reclaimed water.

[0068] The mass ratio of the phosphate buffer, potassium permanganate, ferrous sulfide, modified chitosan, modified polyaspartic acid, tetrasodium diacetate of glutamic acid, and 1L of wastewater is 0.0035:0.0003:0.002:0.001:0.002:0.001:1.

[0069] The mass ratio of the S1 modified chitosan to part of the deionized water is 1:190;

[0070] The mass ratio of the modified chitosan to the remaining deionized water is 1:9.

[0071] The pH adjuster is either a hydrogen chloride solution or a sodium hydroxide solution. The pH is adjusted to 7.5-8.5 by adding the pH adjuster dropwise.

[0072] The phosphate buffer is a mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate;

[0073] The mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate is 1:2.5.

[0074] The modified chitosan was prepared through the following steps: Deionized water and chitosan were added to a reaction vessel and stirred at 300-400 rpm for 30-40 minutes. Dilute acetic acid was added and stirred at 200-300 rpm for 5-10 minutes. 2,3-epoxypropyltrimethylammonium chloride solution was added and stirred at 200-400 rpm for 2-4 hours. Sodium hydroxide solution was added and stirred at 60-70℃ for 4-8 hours to obtain a reaction solution. The reaction solution was poured into anhydrous ethanol and stirred at 300-400 rpm for 5-10 minutes. The supernatant was filtered off, and the filter residue was collected. The filter residue was washed 3-5 times with ethanol and 1-2 times with acetone. The washed filter residue was placed in a vacuum drying oven and dried at 40-50℃ for 12-24 hours. To prepare quaternized chitosan, deionized water was added to a reaction vessel and stirred at 200-400 rpm. Quaternized chitosan was then added and stirred for 10-20 minutes to obtain a quaternized chitosan solution. N,N-dimethylformamide was added to a water bath reaction vessel, and the water bath temperature was controlled at 0-5℃. The quaternized chitosan solution was added and stirred at 400-600 rpm. Succinic anhydride was added and stirred at 10-20℃ for 2-4 hours. The stirring speed was then adjusted to 300-500 rpm, and the temperature was controlled at 18-25℃ for 2-4 hours to obtain a reaction solution. The reaction solution was placed in a dialysis bag and dialyzed with deionized water for 2-3 days, changing the water 4-5 times a day. The dialyzed reaction solution was then placed in a vacuum drying oven and dried at 40-50℃ for 24-48 hours to obtain modified chitosan.

[0075] The mass ratio of deionized water to chitosan is 30-40:1;

[0076] The pH value is adjusted to 5-6 by adding dilute acetic acid;

[0077] The sodium hydroxide solution has a concentration of 1% and the pH value is adjusted to 7-9.

[0078] The mass concentration of the 2,3-epoxypropyltrimethylammonium chloride solution is 60%; the molar ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:1.2-1.5.

[0079] The molar ratio of succinic anhydride to quaternized chitosan is 1-2:1;

[0080] The mass ratio of N,N-dimethylformamide to quaternized chitosan is 10-20:1;

[0081] The dialysis bag has a molecular weight cutoff of 3500 Da.

[0082] The modified polyaspartic acid is prepared through the following steps: maleic anhydride and deionized water are added to a reaction vessel and stirred. Ammonia, aminomethylphosphonic acid, and phosphoric acid are added and stirred. The temperature is controlled at 80-90℃, the stirring speed is 200-400 rpm, and the stirring time is 30-60 minutes. The stirring speed is then adjusted to 150-300 rpm, and the temperature is heated to 180-240℃ at a rate of 1-3℃ / minute. The stirring speed is then adjusted to 80-150 rpm, and the stirring time is 1-3 hours to obtain a polysuccinimide intermediate. Sodium hydroxide solution is added to the reaction vessel and stirred. The temperature is controlled at... The mixture is stirred at 70-80℃ and 200-400 rpm for 1-1.5 hours. The reactor temperature is then cooled to 18-25℃ to obtain a polysuccinimide intermediate liquid. This liquid is then poured into anhydrous ethanol and stirred at 80-150 rpm for 10-15 minutes. The liquid is then filtered off to obtain a filter cake. The filter cake is washed with anhydrous ethanol 3-5 times. The washed filter cake is then placed in a vacuum drying oven and dried at 40-60℃ for 24-48 hours to obtain modified polyaspartic acid.

[0083] The mass ratio of maleic anhydride to deionized water is 1:1.5-3;

[0084] The mass ratio of maleic anhydride, ammonia, and aminomethylphosphonic acid is 1:1.6:0.11;

[0085] The mass ratio of the total mass of phosphoric acid to maleic anhydride, ammonia, and aminomethylphosphonic acid is 0.025:1.

[0086] The concentration of ammonia water is 25%-28% (w / w);

[0087] The molar ratio of the sodium hydroxide solution to the polysuccinimide intermediate is 2:1.

[0088] Example 3: A method for preparing reclaimed water based on non-complexed manganese oxidation technology, comprising the following steps:

[0089] S1. Add some deionized water to a magnetic reactor and stir at 400-600 rpm. Add modified chitosan and stir for 30-60 minutes. Add the remaining deionized water to obtain a modified chitosan solution.

[0090] S2. Take 1L of wastewater and place it in a reaction vessel and stir at 150-250 rpm. Add phosphate buffer and stir at 150-250 rpm for 10-20 minutes. Add pH adjuster dropwise to obtain an alkaline water sample.

[0091] S3. Add potassium permanganate to the alkaline water sample and stir at 150-250 rpm for 30 minutes. Add ferrous sulfide and stir at 300-400 rpm for 2 minutes. Adjust the speed to 150-250 rpm and stir for 40 minutes. Add modified chitosan solution and stir at 120-180 rpm for 1 minute. Adjust the speed to 40-60 rpm and stir for 20-30 minutes. Let stand for 90-120 minutes. Transfer the supernatant to a new reactor. Add modified polyaspartic acid to the new reactor and stir at 80-120 rpm for 5-10 minutes. Add tetrasodium diacetate of glutamic acid and stir for 5-10 minutes to obtain clean water.

[0092] S4. Disinfect the clean water using an ultraviolet sterilizer for 30 minutes to obtain reclaimed water.

[0093] The mass ratio of the phosphate buffer, potassium permanganate, ferrous sulfide, modified chitosan, modified polyaspartic acid, tetrasodium diacetate of glutamic acid, and 1L of wastewater is 0.005:0.0005:0.003:0.0015:0.003:0.0015:1.

[0094] The mass ratio of the S1 modified chitosan to part of the deionized water is 1:190;

[0095] The mass ratio of the modified chitosan to the remaining deionized water is 1:9.

[0096] The pH adjuster is either a hydrogen chloride solution or a sodium hydroxide solution. The pH is adjusted to 7.5-8.5 by adding the pH adjuster dropwise.

[0097] The phosphate buffer is a mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate;

[0098] The mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate is 1:2.5.

[0099] The modified chitosan was prepared through the following steps: Deionized water and chitosan were added to a reaction vessel and stirred at 300-400 rpm for 30-40 minutes. Dilute acetic acid was added and stirred at 200-300 rpm for 5-10 minutes. 2,3-epoxypropyltrimethylammonium chloride solution was added and stirred at 200-400 rpm for 2-4 hours. Sodium hydroxide solution was added and stirred at 60-70℃ for 4-8 hours to obtain a reaction solution. The reaction solution was poured into anhydrous ethanol and stirred at 300-400 rpm for 5-10 minutes. The supernatant was filtered off, and the filter residue was collected. The filter residue was washed 3-5 times with ethanol and 1-2 times with acetone. The washed filter residue was placed in a vacuum drying oven and dried at 40-50℃ for 12-24 hours. To prepare quaternized chitosan, deionized water was added to a reaction vessel and stirred at 200-400 rpm. Quaternized chitosan was then added and stirred for 10-20 minutes to obtain a quaternized chitosan solution. N,N-dimethylformamide was added to a water bath reaction vessel, and the water bath temperature was controlled at 0-5℃. The quaternized chitosan solution was added and stirred at 400-600 rpm. Succinic anhydride was added and stirred at 10-20℃ for 2-4 hours. The stirring speed was then adjusted to 300-500 rpm, and the temperature was controlled at 18-25℃ for 2-4 hours to obtain a reaction solution. The reaction solution was placed in a dialysis bag and dialyzed with deionized water for 2-3 days, changing the water 4-5 times a day. The dialyzed reaction solution was then placed in a vacuum drying oven and dried at 40-50℃ for 24-48 hours to obtain modified chitosan.

[0100] The mass ratio of deionized water to chitosan is 30-40:1;

[0101] The pH value is adjusted to 5-6 by adding dilute acetic acid;

[0102] The sodium hydroxide solution has a concentration of 1% and the pH value is adjusted to 7-9.

[0103] The mass concentration of the 2,3-epoxypropyltrimethylammonium chloride solution is 60%; the molar ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:1.2-1.5.

[0104] The molar ratio of succinic anhydride to quaternized chitosan is 1-2:1;

[0105] The mass ratio of N,N-dimethylformamide to quaternized chitosan is 10-20:1;

[0106] The dialysis bag has a molecular weight cutoff of 3500 Da.

[0107] The modified polyaspartic acid is prepared through the following steps: maleic anhydride and deionized water are added to a reaction vessel and stirred. Ammonia, aminomethylphosphonic acid, and phosphoric acid are added and stirred. The temperature is controlled at 80-90℃, the stirring speed is 200-400 rpm, and the stirring time is 30-60 minutes. The stirring speed is then adjusted to 150-300 rpm, and the temperature is heated to 180-240℃ at a rate of 1-3℃ / minute. The stirring speed is then adjusted to 80-150 rpm, and the stirring time is 1-3 hours to obtain a polysuccinimide intermediate. Sodium hydroxide solution is added to the reaction vessel and stirred. The temperature is controlled at... The mixture is stirred at 70-80℃ and 200-400 rpm for 1-1.5 hours. The reactor temperature is then cooled to 18-25℃ to obtain a polysuccinimide intermediate liquid. This liquid is then poured into anhydrous ethanol and stirred at 80-150 rpm for 10-15 minutes. The liquid is then filtered off to obtain a filter cake. The filter cake is washed with anhydrous ethanol 3-5 times. The washed filter cake is then placed in a vacuum drying oven and dried at 40-60℃ for 24-48 hours to obtain modified polyaspartic acid.

[0108] The mass ratio of maleic anhydride to deionized water is 1:1.5-3;

[0109] The mass ratio of maleic anhydride, ammonia, and aminomethylphosphonic acid is 1:1.6:0.11;

[0110] The mass ratio of the total mass of phosphoric acid to maleic anhydride, ammonia, and aminomethylphosphonic acid is 0.025:1.

[0111] The concentration of ammonia water is 25%-28% (w / w);

[0112] The molar ratio of the sodium hydroxide solution to the polysuccinimide intermediate is 2:1.

[0113] Comparative Example 1: The difference between this comparative example and Example 1 is that:

[0114] This comparative example does not include ultraviolet sterilization.

[0115] Comparative Example 2: The difference between this comparative example and Example 1 is that:

[0116] This comparative example does not contain modified chitosan.

[0117] Comparative Example 3 differs from Example 1 in that:

[0118] This comparative example does not contain modified polyaspartic acid or tetrasodium glutamate diacetate.

[0119] Performance testing: The reclaimed water prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 was tested. The relevant performance of the reclaimed water preparation methods based on non-complexed manganese oxidation technology provided in Examples 1-3 and Comparative Examples 1-3 was tested respectively. The test data are recorded in Table 1 below:

[0120]

[0121] The fecal coliform counts in the reclaimed water prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 were 1820 CFU / L, 1815 CFU / L, 1795 CFU / L, 2295 CFU / L, 2010 CFU / L, and 1976 CFU / L, respectively; the suspended solids in the reclaimed water prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 were 51 mg / L, 48 mg / L, 50 mg / L, and 65 mg / L, respectively. / L, 72mg / L, and 63mg / L; the lead content of the reclaimed water prepared in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 was 0.092mg / L, 0.084mg / L, 0.081mg / L, 0.102mg / L, 0.113mg / L, and 0.135mg / L, respectively. It is evident that the reclaimed water prepared by this invention not only has a low fecal coliform count but also a low suspended solids content and a low lead content. This indicates that the reclaimed water preparation method based on non-complexed manganese oxidation technology provided by this invention has a broader market prospect and is more suitable for widespread application.

[0122] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0123] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing reclaimed water based on non-complexed manganese oxidation technology, characterized in that, The method for preparing reclaimed water based on non-complexed manganese oxidation technology includes the following steps: S1. Add some deionized water to a magnetic reactor and stir at 400-600 rpm. Add modified chitosan and stir for 30-60 minutes. Add the remaining deionized water to obtain a modified chitosan solution. S2. Take 1L of wastewater and place it in a reaction vessel and stir at 150-250 rpm. Add phosphate buffer and stir at 150-250 rpm for 10-20 minutes. Add pH adjuster dropwise to obtain an alkaline water sample. S3. Add potassium permanganate to the alkaline water sample and stir at 150-250 rpm for 30 minutes. Add ferrous sulfide and stir at 300-400 rpm for 2 minutes. Adjust the speed to 150-250 rpm and stir for 40 minutes. Add modified chitosan solution and stir at 120-180 rpm for 1 minute. Adjust the speed to 40-60 rpm and stir for 20-30 minutes. Let stand for 90-120 minutes. Transfer the supernatant to a new reactor. Add modified polyaspartic acid to the new reactor and stir at 80-120 rpm for 5-10 minutes. Add tetrasodium diacetate of glutamic acid and stir for 5-10 minutes to obtain clean water. S4. Disinfect the clean water using an ultraviolet sterilizer for 30 minutes to obtain reclaimed water; The modified chitosan was prepared through the following steps: Deionized water and chitosan were added to a reaction vessel and stirred at 300-400 rpm for 30-40 minutes. Dilute acetic acid was added and stirred at 200-300 rpm for 5-10 minutes. 2,3-epoxypropyltrimethylammonium chloride solution was added and stirred at 200-400 rpm for 2-4 hours. Sodium hydroxide solution was added and stirred at 60-70℃ for 4-8 hours to obtain a reaction solution. The reaction solution was poured into anhydrous ethanol and stirred at 300-400 rpm for 5-10 minutes. The supernatant was filtered off, and the filter residue was collected. The filter residue was washed 3-5 times with ethanol and 1-2 times with acetone. The washed filter residue was placed in a vacuum drying oven and dried at 40-50℃ for 12-24 hours. To prepare quaternized chitosan, deionized water was added to a reaction vessel and stirred at 200-400 rpm. Quaternized chitosan was then added and stirred for 10-20 minutes to obtain a quaternized chitosan solution. N,N-dimethylformamide was added to a water bath reaction vessel, and the water bath temperature was controlled at 0-5℃. The quaternized chitosan solution was added and stirred at 400-600 rpm. Succinic anhydride was added and stirred at 10-20℃ for 2-4 hours. The stirring speed was then adjusted to 300-500 rpm, and the temperature was controlled at 18-25℃ for 2-4 hours to obtain a reaction solution. The reaction solution was placed in a dialysis bag and dialyzed with deionized water for 2-3 days, changing the water 4-5 times a day. The dialyzed reaction solution was then placed in a vacuum drying oven and dried at 40-50℃ for 24-48 hours to obtain modified chitosan. The modified polyaspartic acid is prepared through the following steps: maleic anhydride and deionized water are added to a reaction vessel and stirred. Ammonia, aminomethylphosphonic acid, and phosphoric acid are added and stirred. The temperature is controlled at 80-90℃, the stirring speed is 200-400 rpm, and the stirring time is 30-60 minutes. The stirring speed is then adjusted to 150-300 rpm, and the temperature is heated to 180-240℃ at a rate of 1-3℃ / minute. The stirring speed is then adjusted to 80-150 rpm, and the stirring time is 1-3 hours to obtain a polysuccinimide intermediate. Sodium hydroxide solution is added to the reaction vessel and stirred. The temperature is controlled at... The mixture is stirred at 70-80℃ and 200-400 rpm for 1-1.5 hours. The reactor temperature is then cooled to 18-25℃ to obtain a polysuccinimide intermediate liquid. This liquid is then poured into anhydrous ethanol and stirred at 80-150 rpm for 10-15 minutes. The liquid is then filtered off to obtain a filter cake. The filter cake is washed with anhydrous ethanol 3-5 times. The washed filter cake is then placed in a vacuum drying oven and dried at 40-60℃ for 24-48 hours to obtain modified polyaspartic acid.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the phosphate buffer, potassium permanganate, ferrous sulfide, modified chitosan, modified polyaspartic acid, tetrasodium diacetate of glutamic acid, and 1L of wastewater is 0.002-0.005: 0.0001-0.0005: 0.001-0.003: 0.0005-0.0015: 0.001-0.003: 0.0005-0.0015:

1.

3. The preparation method according to claim 1, characterized in that, The mass ratio of the S1 modified chitosan to part of the deionized water is 1:190; The mass ratio of the modified chitosan to the remaining deionized water is 1:

9.

4. The preparation method according to claim 1, characterized in that, The pH adjuster is either a hydrogen chloride solution or a sodium hydroxide solution. The pH is adjusted to 7.5-8.5 by adding the pH adjuster dropwise.

5. The preparation method according to claim 1, characterized in that, The phosphate buffer is a mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate; The mass ratio of sodium dihydrogen phosphate to disodium hydrogen phosphate is 1:2.

5.

6. The preparation method according to claim 1, characterized in that, The mass ratio of deionized water to chitosan is 30-40:1; The pH value is adjusted to 5-6 by adding dilute acetic acid; The sodium hydroxide solution has a concentration of 1% and the pH value is adjusted to 7-9. The mass concentration of the 2,3-epoxypropyltrimethylammonium chloride solution is 60%; the molar ratio of chitosan to 2,3-epoxypropyltrimethylammonium chloride is 1:1.2-1.

5.

7. The preparation method according to claim 1, characterized in that, The molar ratio of succinic anhydride to quaternized chitosan is 1-2:1; The mass ratio of N,N-dimethylformamide to quaternized chitosan is 10-20:1; The dialysis bag has a molecular weight cutoff of 3500 Da.

8. The preparation method according to claim 1, characterized in that, The mass ratio of maleic anhydride to deionized water is 1:1.5-3; The mass ratio of maleic anhydride, ammonia, and aminomethylphosphonic acid is 1:1.6:0.11; The mass ratio of the total mass of phosphoric acid to maleic anhydride, ammonia, and aminomethylphosphonic acid is 0.025:1; The concentration of ammonia water is 25%-28% (w / w); The molar ratio of the sodium hydroxide solution to the polysuccinimide intermediate is 2:1.

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