Oxidizing bactericide, its preparation method and application

Abstract

This invention provides an oxidizing bactericide, its preparation method, and its application. The oxidizing bactericide comprises 30-60 parts of a modified chloramine compound, 5-15 parts of a modified chelating agent, 3-10 parts of a delay agent, 2-8 parts of a synergist, 1-5 parts of a corrosion inhibitor, and water to a total weight of 100 parts. The oxidizing bactericide of this invention exhibits stronger bactericidal effects, higher stability, and a longer shelf life. It also overcomes the drawback of traditional bactericides that easily corrode reusable membranes, significantly reducing the operation, maintenance, and consumable costs of water treatment systems, and possesses promising prospects for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of water treatment technology, and relates to an oxidizing bactericide, and more particularly to an oxidizing bactericide and its preparation method and application. Background Technology

[0002] With the global water shortage becoming increasingly severe, wastewater resource utilization and industrial water conservation have become core development directions in the water treatment field. Among these, the reuse of greywater (reclaimed water) and industrial water recycling are two core pathways to reduce fresh water consumption and wastewater discharge. Microbial growth is one of the core bottlenecks restricting the safe reuse of greywater and the stable operation of industrial circulating water systems. Microbial proliferation in water bodies and on system walls can lead to problems such as the formation of biological slime, microbial-induced corrosion (MIC), reduced heat exchange efficiency, and blockage of pipes and packing materials.

[0003] In water reuse and industrial circulating water systems, bactericides are the core means of microbial control. Chloramine compounds (monochloramine, dichloramine, chloramine-T, etc.) are broad-spectrum oxidizing bactericides. With their advantages of strong bactericidal persistence, low production of trihalomethane carcinogenic byproducts, and excellent ability to penetrate biofilms, they are widely used in water treatment and circulating water disinfection. However, their use has the following problems: (1) Poor stability and short shelf life: Conventional chloramine compounds are easily affected by light, temperature, and water pH. The effective chlorine decomposes and is lost rapidly. They become ineffective after 6 to 12 months of sealed storage at room temperature. Frequent replenishment of the agent is required in the later use, resulting in high operation and maintenance costs. (2) The raw water for water reuse and industrial circulating water contains high concentrations of calcium, magnesium, iron, manganese heavy metals and organic impurities, which are easy to complex with chloramine compounds and consume effective chlorine, greatly reducing the oxidizing and bactericidal activity of chloramine compounds.

[0004] Therefore, how to provide an oxidizing bactericide that can improve stability and bactericidal effect has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide an oxidizing bactericide, its preparation method, and its application. The oxidizing bactericide is prepared by compounding multiple components. Compared with traditional chloramine compounds, the oxidizing bactericide of the present invention has the advantages of long-term chlorine release, effective resistance to metal ion interference, and prevention of membrane damage, making it suitable for large-scale industrial applications in wastewater reuse and industrial circulating water systems.

[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides an oxidizing bactericide comprising, by weight, 30-60 parts of modified chloramine compound, 5-15 parts of modified chelating agent, 3-10 parts of delay agent, 2-8 parts of synergist, 1-5 parts of corrosion inhibitor, and water to a total weight of 100 parts.

[0007] This invention prepares an oxidizing bactericide by compounding modified chloramine compounds, modified chelating agents, delay agents, synergists, and corrosion inhibitors. The resulting bactericide exhibits strong stability, strong resistance to metal ion interference, long-lasting chlorine retention, and prevention of damage to reuse membranes. The modified chloramine compound, after alkylation modification, provides the available chlorine required for sterilization during use, achieving its bactericidal effect by disrupting microbial cell walls and enzyme systems. Furthermore, the modified chloramine compound effectively enhances its stability, reducing the problem of rapid decomposition and loss of available chlorine in conventional chloramine compounds, thus achieving a slow release of available chlorine. The modified chelating agent, after modification, efficiently complexes with metal ions such as calcium, magnesium, iron, and manganese in water, preventing them from affecting the activity of available chlorine and the stability of the bactericide. The delay agent extends the shelf life of the bactericide and inhibits the decomposition rate of available chlorine. The synergist works synergistically with the modified chloramine compound to promote the release of available chlorine and enhance the bactericidal effect. Corrosion inhibitors can prevent oxidizing bactericides from damaging reusable membranes during use, avoiding issues such as membrane flux decline, reduced desalination rate, and shortened lifespan, thus lowering equipment replacement costs. The oxidizing bactericide provided by this invention simultaneously addresses industry pain points such as long-term storage, high-efficiency sterilization, resistance to impurity interference, and protection against damage to reusable membranes, reducing water treatment operation and maintenance costs and consumable costs, and is suitable for large-scale industrial applications of greywater reuse and industrial circulating water systems.

[0008] Preferably, by weight, the oxidizing bactericide comprises: 40-50 parts of modified chloramine compound, 8-12 parts of modified chelating agent, 5-8 parts of delay agent, 4-6 parts of synergist, 2-4 parts of corrosion inhibitor, and water to a total weight of 100 parts.

[0009] More preferably, the oxidizing bactericide comprises, by weight: 45 parts modified chloramine compound, 10 parts modified chelating agent, 6.5 parts delay agent, 5 parts synergist, 3 parts corrosion inhibitor, and water to a total weight of 100 parts.

[0010] Preferably, the method for preparing the modified chloramine compound includes: S1. Mix chloramine-B with water, add chloroalkane reagent, and after reaction, obtain crude reactant; S2. The crude reactant is subjected to vacuum distillation and drying to obtain the modified chloramine compound.

[0011] Preferably, the weight ratio of chloramine-B to water in step S1 is 1:(2.5~3.5).

[0012] Preferably, the molar ratio of chloramine-B and the chloroalkane reagent in step S1 is (1.0~1.5):1.

[0013] Preferably, the chloroalkane reagent in step S1 includes any one or a combination of at least two of chloromethane, chloroethane, or chloropropane.

[0014] Preferably, the reaction temperature in step S1 is 35~45℃, and the reaction time is 2~4h.

[0015] Preferably, the temperature of the vacuum distillation in step S2 is 55~65℃, the time of the vacuum distillation is 2~3h, and the vacuum degree is -0.07~-0.85MPa.

[0016] Preferably, the drying in step S2 includes vacuum drying; the conditions for vacuum drying are: temperature 60~70℃, vacuum degree -0.08 ~ -0.09 MPa, and time 4~6h.

[0017] Preferably, the modified chelating agent includes modified disodium ethylenediaminetetraacetate and / or modified pentasodium diethylenetriaminepentaacetate.

[0018] In this invention, the modified chelating agent can exert a stronger complexing effect, and can exert a complexing effect in wastewater / industrial circulating water with high concentrations of calcium, magnesium, iron, manganese and heavy metal ions, reducing the consumption of available chlorine and allowing the oxidizing bactericide to exert a better bactericidal effect.

[0019] Preferably, the modified disodium ethylenediaminetetraacetate is hydroxylated modified disodium ethylenediaminetetraacetate.

[0020] Preferably, the sodium diethylenetriaminepentaacetate is anamine-modified sodium diethylenetriaminepentaacetate.

[0021] Preferably, the modification step of the modified disodium ethylenediaminetetraacetate includes: A1. Add activated carbon to an aqueous solution of disodium ethylenediaminetetraacetate, decolorize, and then filter to obtain a purified solution. A2. Add ethylene glycol, glycerol and sodium acetate to the purified solution, stir well, add alkaline reagent to adjust the pH to alkaline, and obtain the reaction product after reaction. A3. The reaction product is subjected to heat treatment to obtain a aging product; A4. After cooling, an acidic reagent is added to the ripened product to adjust the pH to neutral, anhydrous ethanol is added, and the mixture is stirred evenly and then dried to obtain the modified disodium ethylenediaminetetraacetate.

[0022] Preferably, the mass concentration of the disodium ethylenediaminetetraacetate aqueous solution in step A1 is 20-25%.

[0023] Preferably, the amount of activated carbon added in step A1 is 0.3 to 0.8% of the mass of disodium ethylenediaminetetraacetate.

[0024] Preferably, the decolorization treatment time in step A1 is 20-40 minutes, and the decolorization treatment temperature is 20-40°C.

[0025] Preferably, in step A2, the amount of ethylene glycol added is 0.2-1.0% of the mass of disodium ethylenediaminetetraacetate, the amount of glycerol added is 0.1-0.5% of the mass of disodium ethylenediaminetetraacetate, and the amount of sodium acetate added is 0.5-1.5% of the mass of disodium ethylenediaminetetraacetate.

[0026] Preferably, the alkaline reagent in step A2 includes a sodium hydroxide solution, wherein the mass concentration of the sodium hydroxide solution is 0.5-5%.

[0027] Preferably, the alkalinity mentioned in step A2 refers to a pH of 8.0 to 9.0.

[0028] Preferably, the reaction temperature in step A2 is 60~70℃, and the reaction time is 2~4h.

[0029] Preferably, the temperature of the heat preservation treatment in step A3 is 75~85℃, and the heat preservation treatment time is 1~1.5h.

[0030] Preferably, the cooling in step A4 refers to cooling to 40~50℃.

[0031] Preferably, the acidic reagent in step A4 includes a hydrochloric acid solution with a mass concentration of 3-10%.

[0032] Preferably, the neutrality mentioned in step A4 refers to a pH of 6.5 to 7.5.

[0033] Preferably, the amount of anhydrous ethanol added in step A4 is 2 to 4% of the mass of the aging product.

[0034] Preferably, the drying in step A4 includes spray drying and / or vacuum drying; the conditions for spray drying are: inlet air temperature 165~175℃, outlet air temperature 80~90℃; the conditions for vacuum drying are: temperature 60~70℃, vacuum degree -0.08 ~ -0.09 MPa, and time 4~6h.

[0035] Preferably, the modification step of the modified diethylenetriaminepentaacetate pentasodium includes: B1. Ethylenediamine was added to an aqueous solution of diethylenetriaminepentaacetate pentasodium, and the crude modified product was obtained after the reaction. B2. The crude modified material is dried to obtain the modified sodium diethylenetriaminepentaacetate; preferably, the mass concentration of the sodium diethylenetriaminepentaacetate aqueous solution in step B1 is 20-25%.

[0036] Preferably, the molar ratio of diethylenetriaminepentaacetic acid pentasodium and ethylenediamine in step B1 is 1:(1.3~1.5).

[0037] Preferably, the reaction temperature in step B1 is 48~56℃, and the reaction time is 3.5~4.5h.

[0038] Preferably, the drying in step B2 includes vacuum drying; the conditions for vacuum drying are: temperature 60~70℃, vacuum degree -0.08 ~ -0.09 MPa, and time 4~6h.

[0039] In this invention, the modified sodium diethylenetriaminepentaacetate has a chelating capacity of ≥100 mg / g for calcium, magnesium and iron ions in water.

[0040] Preferably, the delay agent includes any one or a combination of at least two of sodium peroxide, magnesium peroxide, disodium hydrogen phosphate, and sodium dihydrogen phosphate.

[0041] More preferably, the delay agent is a combination of disodium hydrogen phosphate and sodium dihydrogen phosphate; the mass ratio of disodium hydrogen phosphate to sodium dihydrogen phosphate is 1:(0.8~1.2).

[0042] In this invention, when the delay agent is a combination of disodium hydrogen phosphate and sodium dihydrogen phosphate, the two can form a buffer system to stabilize the pH of the oxidizing bactericide, further inhibit the decomposition of available chlorine, and extend the shelf life of the bactericide.

[0043] Preferably, the synergist is any one or a combination of at least two of potassium bromide, ammonium chloride, and ammonium sulfate.

[0044] In this invention, the synergist can work synergistically with available chlorine to reduce the amount of modified chloramine compound used, while accelerating the oxidation rate of available chlorine on microorganisms and improving sterilization efficiency.

[0045] Preferably, the corrosion inhibitor includes an organophosphonate corrosion inhibitor.

[0046] More preferably, the organophosphonate corrosion inhibitor includes aminotrimethylenephosphonic acid and / or hydroxyethylidene diphosphonic acid.

[0047] In this invention, the corrosion inhibitor can effectively inhibit the oxidative corrosion of the surface of the recycled membrane material by the bactericide, increase the service life of the recycled membrane material, and reduce the operation and maintenance and consumable costs of water treatment.

[0048] In a second aspect, the present invention provides a method for preparing an oxidizing bactericide as described in the first aspect, the method comprising the following steps: A modified chloramine compound, a modified chelating agent, a delay agent, a synergist, a corrosion inhibitor, and water are mixed evenly to obtain an oxidizing bactericide.

[0049] Preferably, the mixing temperature is 20~40℃.

[0050] Thirdly, the present invention provides an application of the oxidizing bactericide as described in the first aspect, wherein the oxidizing bactericide is used for the sterilization treatment of greywater and / or industrial circulating water.

[0051] Preferably, the dosage of the oxidizing bactericide is 20~100 mg / L.

[0052] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention combines modified chloramine compounds, modified chelating agents, delay agents, synergists, corrosion inhibitors, and water in a specific ratio to prepare a composite oxidizing bactericide with excellent stability, strong resistance to metal ion interference, long-lasting chlorine locking, and targeted protection function for reusable membranes.

[0053] The modified chloramine compound in the bactericide undergoes alkylation modification, resulting in higher chemical stability when used as an active chlorine source. It exhibits superior biofilm penetration ability, achieving long-lasting antibacterial and bactericidal effects. The frequency of agent addition is significantly reduced during use, effectively decreasing system maintenance costs. The modified chelating agent, compared to commercially available conventional chelating agents, has a stronger chelating ability for metal ions such as calcium, magnesium, iron, and manganese in water, greatly improving the bactericide's anti-interference performance in high-metal-ion water environments and preventing the rapid decomposition and loss of effective bactericidal components. The delay agent passivates metal ions in the water, reduces the consumption of the main bactericidal components by reducing substances, and inhibits the rapid degradation of effective chlorine, thus extending the effective bactericidal effect of the agent in the water and improving the product's shelf life. The synergist works synergistically with the modified chloramine compound to further enhance the overall bactericidal efficacy of the system. The corrosion inhibitor protects the reuse membrane modules during the sterilization process, preventing damage to the membrane material from the bactericide, fundamentally solving problems such as membrane flux decline, reduced desalination rate, and shortened service life, and reducing membrane module replacement costs.

[0054] Compared to existing chloramine-based bactericides, the oxidizing bactericide of this invention has higher chemical stability, better bactericidal effect, and longer shelf life. It is less susceptible to interference from metal ions in complex water conditions such as reclaimed water and industrial circulating water. At the same time, it overcomes the technical drawbacks of traditional bactericides, such as easy corrosion and damage to reuse membranes. It can simultaneously solve four common pain points in the industry: long-term storage, high-efficiency bactericidal effect, resistance to impurity interference, and protection of reuse membranes. It significantly reduces the operation and maintenance costs and consumable costs of water treatment systems and has good prospects for industrial application, especially suitable for large-scale promotion and application of reclaimed water reuse and industrial circulating water systems. Detailed Implementation

[0055] The advantages and features of the present invention, as well as the methods for achieving said advantages and features, will be more readily understood by referring to the following detailed description of embodiments. However, the present invention may be embodied in various other forms and should not be construed as limited to the embodiments set forth herein. The embodiments disclosed herein are provided so that the disclosure of the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0056] The terminology used in this specification is intended only to describe certain implementations and should in no way limit the invention.

[0057] Unless otherwise expressly used, the singular form includes the meaning of the plural form.

[0058] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Any term defined in a comprehensive dictionary shall be interpreted as having the same meaning in the context of the relevant field and, unless expressly defined otherwise, shall not be interpreted as having an idealistic or overly formalistic meaning.

[0059] Unless otherwise specified, all percentages mentioned in this invention refer to mass percentages.

[0060] Unless otherwise specified, all concentrations mentioned in this invention refer to mass concentrations.

[0061] Unless otherwise specified, all water mentioned in this invention is deionized water.

[0062] Unless otherwise specified, the chloropropane in this invention may be 1-chloropropane or 2-chloropropane.

[0063] Example 1 This embodiment provides an oxidizing bactericide and its preparation method. The oxidizing bactericide comprises the following components in parts by weight: 45 parts modified chloramine compound, 10 parts modified chelating agent, 6.5 parts delay agent, 5 parts synergist, 3 parts corrosion inhibitor, and water to a total weight of 100 parts.

[0064] The preparation method of the oxidizing bactericide includes: mixing modified chloramine compound, modified chelating agent, delay agent, synergist, corrosion inhibitor and water at 25°C to obtain the oxidizing bactericide.

[0065] The modified chelating agent is hydroxylated disodium ethylenediaminetetraacetate; the delay agent is a combination of disodium hydrogen phosphate and sodium dihydrogen phosphate (the mass ratio of disodium hydrogen phosphate to sodium dihydrogen phosphate is 1:1); the synergist is potassium bromide; and the corrosion inhibitor is hydroxyethylidene diphosphonic acid.

[0066] Methods for preparing modified chloramine compounds include: S1. Mix chloramine-B with 3 times its weight of water, add chloroethane (the molar ratio of chloramine-B to chloroethane is 1.2:1), stir and react at 40°C for 3 hours to obtain crude reactant; S2. The crude reactant from step S1 was subjected to vacuum distillation (conditions: temperature 60℃, time 2.5h, vacuum degree -0.08MPa) and vacuum drying (conditions: temperature 65℃, vacuum degree -0.09 MPa, time 5h) to obtain the modified chloramine compound.

[0067] The modified chelating agent is hydroxylated disodium ethylenediaminetetraacetate, and its preparation method includes: A1. Add 0.5% (by mass) of activated carbon to a 23% (by mass) aqueous solution of disodium ethylenediaminetetraacetate, and decolorize at 25°C for 30 min to obtain a purified solution. A2. Add 0.5% (by mass) ethylene glycol, 0.2% (by mass) glycerol, and 0.8% (by mass) sodium acetate to the purified solution. After stirring evenly, add a 2% (by mass) sodium hydroxide solution to adjust the pH to 8.5. React at 65°C for 3 hours to obtain the reaction product. A3. The reaction product was kept at 80℃ for 1.2h to obtain the ripened product; A4. Cool down to 45℃, add 5% hydrochloric acid solution to the ripening product to adjust the pH to 7.0, add 3% anhydrous ethanol by mass of the ripening product, stir evenly, and then spray dry (conditions: inlet air temperature 170℃, outlet air temperature 85℃). The white powder obtained is hydroxylated modified disodium ethylenediaminetetraacetate.

[0068] Example 2 This embodiment provides an oxidizing bactericide and its preparation method. The oxidizing bactericide comprises the following components in parts by weight: 30 parts modified chloramine compound, 15 parts modified chelating agent, 3 parts delay agent, 8 parts synergist, 1 part corrosion inhibitor, and water to a total weight of 100 parts.

[0069] The preparation method of the oxidizing bactericide includes: mixing modified chloramine compound, modified chelating agent, delay agent, synergist, corrosion inhibitor and water at 40°C to obtain the oxidizing bactericide.

[0070] The modified chelating agent is amination-modified diethylenetriaminepentaacetic acid pentasodium; the delay agent is sodium peroxide; the synergist is a combination of ammonium chloride and ammonium sulfate (mass ratio 3:1); and the corrosion inhibitor is aminotrimethylenephosphonic acid.

[0071] Methods for preparing modified chloramine compounds include: S1. Mix chloramine-B with 2.5 times its weight of water, add chloromethane (the molar ratio of chloramine-B to chloroethane is 1.0:1), stir the mixture at 35°C for 4 hours to obtain the crude reactant; S2. The crude reactant from step S1 was subjected to vacuum distillation (conditions: temperature 55℃, time 3h, vacuum degree -0.085MPa) and vacuum drying (conditions: temperature 60℃, vacuum degree -0.08MPa, time 6h) to obtain the modified chloramine compound.

[0072] The modified chelating agent is amination-modified sodium diethylenetriaminepentaacetate, and the preparation method includes: B1. Ethylenediamine (molar ratio of diethylenetriaminepentaacetate to ethylenediamine is 1:1.5) was added to a 20% aqueous solution of diethylenetriaminepentaacetate and ethylenediamine, and the mixture was reacted at 48°C for 4.5 h to obtain a crude modified product. B2. The crude modified material was vacuum dried (conditions: temperature 70℃, vacuum degree -0.09 MPa, time 4h) to obtain amination-modified diethylenetriaminepentaacetic acid pentasodium.

[0073] Example 3 This embodiment provides an oxidizing bactericide and its preparation method. The oxidizing bactericide comprises the following components in parts by weight: 60 parts modified chloramine compound, 5 parts modified chelating agent, 10 parts delay agent, 2 parts synergist, 5 parts corrosion inhibitor, and water to a total weight of 100 parts.

[0074] The preparation method of the oxidizing bactericide includes: mixing modified chloramine compound, modified chelating agent, delay agent, synergist, corrosion inhibitor and water at 20°C to obtain the oxidizing bactericide.

[0075] The modified chelating agent is hydroxylated disodium ethylenediaminetetraacetate; the delay agent is a combination of sodium peroxide and magnesium peroxide (mass ratio 1:1); the synergist is a combination of potassium bromide, ammonium chloride, and ammonium sulfate (mass ratio 3:1:1); and the corrosion inhibitor is aminotrimethylenephosphonic acid.

[0076] Methods for preparing modified chloramine compounds include: S1. Mix chloramine-B with 3.5 times the weight of water, add chloromethane (the molar ratio of chloramine-B to chloropropane is 1.5:1), stir and react at 45°C for 2 hours to obtain crude reactant; S2. The crude reactant from step S1 was subjected to vacuum distillation (conditions: temperature 65℃, time 2h, vacuum degree -0.07MPa) and vacuum drying (conditions: temperature 70℃, vacuum degree -0.09MPa, time 4h) to obtain the modified chloramine compound.

[0077] The modified chelating agent is hydroxylated disodium ethylenediaminetetraacetate, and its preparation method includes: A1. Add 0.3% activated carbon to a 20% (w / w) aqueous solution of disodium ethylenediaminetetraacetate and decolorize at 40°C for 20 min to obtain a purified solution. A2. Add 0.2% (by mass) ethylene glycol, 0.5% (by mass) glycerol, and 1.5% (by mass) sodium acetate to the purified solution. After stirring evenly, add a 5% (by mass) sodium hydroxide solution to adjust the pH to 9.0. React at 70°C for 2 hours to obtain the reaction product. A3. The reaction product is kept at 75°C for 1.5 hours to obtain the ripened product; A4. Cool to 40℃, add 3% hydrochloric acid solution to the ripening product to adjust the pH to 6.5, add 2% anhydrous ethanol (by weight of the ripening product), stir evenly, and then vacuum dry (conditions: temperature 60℃, vacuum degree -0.08MPa, time 4h). The resulting white powder is hydroxylated modified disodium ethylenediaminetetraacetate.

[0078] Example 4 This embodiment provides an oxidizing bactericide and its preparation method. By weight, the oxidizing bactericide comprises the following components: 40 parts of modified chloramine compound, 12 parts of modified chelating agent, 5 parts of delay agent, 6 parts of synergist, 2 parts of corrosion inhibitor, and water to a total weight of 100 parts.

[0079] The preparation methods for the oxidizing bactericide, the modified chloramine compound, and the modified chelating agent are all the same as in Example 1.

[0080] The delay agent is magnesium peroxide; the synergist is disodium hydrogen phosphate and sodium dihydrogen phosphate (1:0.8); and the corrosion inhibitor is aminotrimethylene phosphonic acid.

[0081] Example 5 This embodiment provides an oxidizing bactericide and its preparation method. The oxidizing bactericide comprises the following components by weight: 50 parts of modified chloramine compound, 8 parts of modified chelating agent, 8 parts of delay agent, 4 parts of synergist, 4 parts of corrosion inhibitor, and water to a total weight of 100 parts.

[0082] The preparation methods for the oxidizing bactericide, the modified chloramine compound, and the modified chelating agent are all the same as in Example 1.

[0083] The delay agent is sodium peroxide; the synergist is disodium hydrogen phosphate and sodium dihydrogen phosphate (1:1.2); and the corrosion inhibitor is hydroxyethylidene diphosphonic acid.

[0084] Example 6 This embodiment provides an oxidizing bactericide and its preparation method. The difference between Example 6 and Example 1 is that in Example 6, chloroethane in the modified chloramine compound preparation method of Example 1 is replaced with chloromethane (the amount added is the same as in Example 1), while the types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0085] Example 7 This embodiment provides an oxidizing bactericide and its preparation method. The difference between Example 7 and Example 1 is that in Example 7, the synergist in Example 1 is changed from potassium bromide to an equal part by weight of ammonium chloride. The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0086] Example 8 This embodiment provides an oxidizing bactericide and its preparation method. The difference between Example 8 and Example 1 is that in Example 8, the synergist in Example 1 is changed from potassium bromide to an equal part by weight of ammonium sulfate. The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0087] Example 9 This embodiment provides an oxidizing bactericide and its preparation method. The difference between Example 9 and Example 1 is that the modified chelating agent in Example 1 is replaced with an equal mass of amination-modified diethylenetriaminepentaacetic acid pentasodium. The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0088] The preparation method of amination-modified diethylenetriaminepentaacetic acid pentasodium includes: B1. Ethylenediamine (molar ratio of diethylenetriaminepentaacetate to ethylenediamine is 1:1.4) was added to a 23% aqueous solution of diethylenetriaminepentaacetate and sodium ethylenediamine, and the mixture was reacted at 52°C for 4 hours to obtain a crude modified product. B2. The crude modified material was vacuum dried (conditions: temperature 65℃, vacuum degree -0.09 MPa, time 5h) to obtain amination-modified diethylenetriaminepentaacetic acid pentasodium.

[0089] Example 10 This embodiment provides an oxidizing bactericide and its preparation method. The difference between Example 9 and Example 1 is that the corrosion inhibitor in Example 9 is changed from hydroxyethylidene diphosphonic acid to aminotrimethylene phosphonic acid. The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0090] Comparative Example 1 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 1 and Example 1 is that the modified chloramine compound in Example 1 is replaced with an equal part by weight of chloramine-B (without modification treatment). The types, amounts, steps and conditions of the other components are the same as in Example 1.

[0091] Comparative Example 2 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 2 and Example 1 is that the modified chloramine compound in Example 1 is replaced with an equal part by weight of monochloramine (without modification treatment) in Comparative Example 2. The types, amounts, steps and conditions of the other components are the same as those in Example 1.

[0092] Comparative Example 3 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 3 and Example 1 is that the chloroethane in the modified chloramine compound preparation method in Example 1 is replaced with chloroform (the amount added is the same as in Example 1). The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0093] Comparative Example 4 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 4 and Example 1 is that the modified chelating agent in Comparative Example 4 is changed from hydroxylated modified disodium ethylenediaminetetraacetate to an equal part by weight of disodium ethylenediaminetetraacetate (without modification treatment). The types, amounts, steps and conditions of the remaining components are the same as those in Example 1.

[0094] Comparative Example 5 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 5 and Example 1 is that the modified chelating agent in Comparative Example 5 is changed from hydroxylated ethylenediaminetetraacetic acid disodium salt to an equal weight of diethylenetriaminepentaacetic acid pentasodium salt (without modification treatment). The types, amounts, steps and conditions of the remaining components are the same as those in Example 1.

[0095] Comparative Example 6 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 6 and Example 1 is that Comparative Example 6 does not add a synergist, but instead uses an equal part by weight of a modified chloramine compound (prepared in the same way as in Example 1). The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0096] Comparative Example 7 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 7 and Example 1 is that potassium bromide in Example 1 is replaced with an equal amount of calcium bromide in Comparative Example 7. The types, amounts, steps and conditions of the remaining components are the same as those in Example 1.

[0097] Comparative Example 8 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 8 and Example 1 is that the synergist in Comparative Example 8 is replaced by an equal part by weight of ammonium bicarbonate instead of potassium bromide in Example 1. The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0098] Comparative Example 9 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 9 and Example 1 is that Comparative Example 9 does not add a delay agent, but instead uses an equal part by weight of a modified chloramine compound (prepared in the same way as in Example 1). The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0099] Comparative Example 10 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 10 and Example 1 is that the delay agent in Comparative Example 10 is changed from a combination of disodium hydrogen phosphate and sodium dihydrogen phosphate to an equal weight of trisodium phosphate. The types, amounts, steps and conditions of the other components are the same as those in Example 1.

[0100] Comparative Example 11 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 11 and Example 1 is that Comparative Example 11 does not add a corrosion inhibitor, but instead uses an equal part by weight of a modified chloramine compound (prepared in the same way as in Example 1). The types, amounts, steps and conditions of the remaining components are the same as in Example 1.

[0101] Comparative Example 12 This comparative example provides an oxidizing bactericide and its preparation method. The difference between Comparative Example 12 and Example 1 is that the corrosion inhibitor in Comparative Example 12 is changed from hydroxyethylidene diphosphonic acid to an equal part by weight of ethylenediaminetetramethylenephosphonic acid. The types, amounts, steps and conditions of the remaining components are the same as those in Example 1.

[0102] Performance Test 1: Sterilization Effect Test Test samples: Oxidizing bactericides of Examples 1-10 and Comparative Examples 1-12.

[0103] Test procedure: Refer to the quantitative bactericidal test method for suspension in the "Disinfection Technical Specifications" (2002 edition), using Escherichia coli in water (initial concentration 8.5 × 10⁻⁶). 5The test strain was identified as CFU / mL. During the test, 30 mg / L of the test sample was added to the sample water. The sterilization rate was measured after 20 minutes of contact at 25°C and a stirring speed of 100 rpm. Sterilization rate (%) = (Average colony count in the initial state - Average colony count after 20 minutes of contact) / (Average colony count in the initial state) × 100%. Three replicates were set up for each group, and the average value was taken.

[0104] The test results are shown in Table 1 below.

[0105] Performance Test 2: Available Chlorine Content Test Test samples: Oxidizing bactericides of Examples 1-10 and Comparative Examples 1-12 after being placed at 45°C for 60 days; Oxidizing bactericides of Examples 1-10 and Comparative Examples 1-12 prepared within 10 days (stored in the dark at 25°C).

[0106] Test Procedure: Measure 10 mL of the test sample and place it in a 250 mL iodine flask. Add 50 mL of deionized water, 10 mL of glacial acetic acid, and 10 mL of 10% potassium iodide solution. Shake well and place in the dark for 10 min. Titrate with 0.05 mol / L sodium thiosulfate standard solution until the solution turns pale yellow. Add 1 mL of starch indicator and continue titrating until the blue color fades and does not recover within 30 seconds. Record the volume of sodium thiosulfate standard solution consumed. Simultaneously perform a blank test (replace the sample with 10 mL of deionized water, and follow the same procedure). Calculate the effective chlorine concentration using the formula: C = (V2-V1)×N×M / Vwater, where C is the effective chlorine concentration (ppm), N is the equivalent concentration of sodium thiosulfate standard solution (mol / L), V2 is the volume of sodium thiosulfate consumed in the sample (mL), V1 is the volume of sodium thiosulfate consumed in the blank (mL), Vwater is the sample volume (mL), and M is the molar mass of chlorine. Test 3 parallel samples per group and take the average value.

[0107] The test results are shown in Table 1 below.

[0108] Performance Test 3: Corrosion Resistance Test Test samples: Oxidizing bactericides of Examples 1-10 and Comparative Examples 1-12.

[0109] Test Method: Simulating actual water reuse conditions, the test temperature was 25±2℃, the operating pressure was 0.2MPa, and the influent was recycled water (relevant indicators: COD=48mg / L, turbidity=4NTU, total heavy metal ion content 0.009mg / L). After adding 30mg / L of test sample to the recycled water, operational testing was conducted (the recycled water membrane material was a polyamide membrane, model: CPA3-LD, molecular weight cutoff 100Da, membrane area 0.4m², pore size 0.0001μm). Operating conditions were: continuous operation for 720h. After operation, membrane flux and membrane surface oxidation degree were measured. Three parallel samples were tested in each group, and the average value was taken.

[0110] Membrane flux test procedure: Use constant pressure filtration method to record the permeate flow rate through the membrane per hour and calculate the membrane flux (unit: L / (m²·h)). Membrane flux retention rate (%) = (membrane flux after n hours of operation / initial membrane flux) × 100%.

[0111] Membrane surface oxidation test procedure: Fourier transform infrared spectroscopy (FTIR) is used to test the changes in functional groups on the membrane surface. The contact angle of the membrane surface before and after operation is compared (oxidation will reduce the contact angle of the membrane surface), and the contact angle change rate is calculated. Contact angle change rate (%) = Initial contact angle − Contact angle after n hours of operation / Initial contact angle × 100%.

[0112] Criteria for judging the degree of oxidation: a contact angle change rate of ≤5% indicates slight oxidation, ≤10% indicates moderate oxidation, and >10% indicates severe oxidation.

[0113] The test results are shown in Table 1 below.

[0114] Table 1 Test results show that the oxidizing bactericides of the present invention exhibit excellent bactericidal performance, stability, and corrosion resistance to wastewater reuse membranes. The oxidizing bactericides of Examples 1-10 of the present invention achieved a bactericidal rate of over 95% against *E. coli* within 20 minutes, with a maximum of 99.8%. In accelerated stability testing, after being placed at 45°C for 60 days (equivalent to 2 years at room temperature), the effective chlorine content of the oxidizing bactericides of Examples 1-10 was tested. The difference in effective chlorine concentration was smaller than that of Comparative Examples 1-12, indicating that the oxidizing bactericides of Examples 1-10 of the present invention have excellent stability. This demonstrates that the effective chlorine concentration of the oxidizing bactericides of the present invention remains high even after 2 years of placement at room temperature. In corrosion resistance testing, the oxidizing bactericides of Examples 1-10 showed lower corrosivity to wastewater reuse membranes. After 30 days of operation, the membrane flux retention rate was over 85%, and the contact angle change rate was below 5.8%, indicating low corrosivity to wastewater reuse membranes and reducing membrane module replacement costs. The bactericidal effect, stability (available chlorine concentration), and corrosion resistance of Examples 1-10 are better than those of Comparative Examples 1-2, indicating that in the oxidizing bactericide of the present invention, the modified chloramine compound interacts with other components, resulting in a composition with better bactericidal effect, stability, and corrosion resistance. Replacing it with other bactericides or not modifying chloramine-B weakens the synergistic effect between components, leading to poorer bactericidal effect, stability, and corrosion resistance in the final composition. Furthermore, comparing Examples 1-10 with Comparative Example 3 shows that the choice of chloroalkane reagent in the modified chloramine compound affects the structure of the resulting modified chloramine compound, causing changes in its bactericidal effect, stability, and corrosion resistance. In the present invention, the chloroalkane reagent is preferably one or a mixture of chloromethane, chloroethane, or chloropropane. The bactericidal effect, stability (available chlorine concentration), and corrosion resistance of Examples 1-10 are better than those of Comparative Examples 4 and 5, indicating that the modified chelating agent, as a component of the oxidizing bactericide, results in a better final product. The modified chelating agent in this invention has a higher chelating capacity for calcium, magnesium, iron, and manganese ions in water, avoiding the consumption of available chlorine by these metal ions and reducing the bactericidal effect. Simultaneously, the modified chelating agent, as a component of the oxidizing bactericide, can also improve the stability and corrosion resistance of the bactericide. The bactericidal effect, stability (available chlorine concentration), and corrosion resistance of Examples 1-10 are better than those of Comparative Examples 6-8, indicating that in this invention, there is a synergistic effect between the synergist and other components. The absence of the synergist or its replacement results in a decrease in the bactericidal effect, stability (available chlorine concentration), and corrosion resistance of the final bactericide. In this invention, the synergist is preferably one or a mixture of potassium bromide, ammonium chloride, and ammonium sulfate. Potassium bromide, ammonium chloride, and ammonium sulfate, as synergists, can synergistically work with available chlorine, reducing the amount of available chlorine used, while accelerating the oxidation rate of microorganisms by available chlorine, thus greatly improving the bactericidal efficiency.The bactericidal effect, stability (available chlorine concentration), and corrosion resistance of Examples 1-10 are better than those of Comparative Examples 9 and 10, indicating that using one or more of sodium peroxide, magnesium peroxide, disodium hydrogen phosphate, and sodium dihydrogen phosphate as a delay agent is more beneficial in improving the bactericidal effect, stability, and corrosion resistance of the bactericide. The delay agent can form a buffer system in the bactericide to stabilize the pH value of the bactericide, further inhibiting the rapid decomposition of available chlorine, achieving effective chlorine release, and reducing the damage of available chlorine to the reuse membrane. The bactericidal effect, stability (available chlorine concentration), and corrosion resistance of Examples 1-10 are better than those of Comparative Examples 11 and 12, indicating that the addition and type of corrosion inhibitor have a significant impact on the bactericidal effect, stability (available chlorine concentration), and corrosion resistance of the final product. This invention preferably uses one or more of aminotrimethylene phosphonic acid and hydroxyethylidene diphosphonic acid as corrosion inhibitors.

[0115] This invention combines modified chloramine compounds, modified chelating agents, delay agents, synergists, corrosion inhibitors, and water in a specific ratio to prepare a composite oxidizing bactericide with excellent stability, strong resistance to metal ion interference, long-lasting chlorine retention, and targeted protection for reuse membranes. Compared with existing chloramine bactericides, this oxidizing bactericide exhibits higher chemical stability, superior bactericidal effect, and longer shelf life. It is less susceptible to metal ion interference in complex water qualities such as reclaimed water and industrial circulating water, while overcoming the technical drawbacks of traditional bactericides, such as easy corrosion and damage to reuse membranes. It simultaneously addresses four common industry pain points: long-lasting storage, high-efficiency bactericidal effect, resistance to impurity interference, and protection of reuse membranes, significantly reducing the operation and maintenance costs and consumable costs of water treatment systems. It has excellent prospects for industrial application, especially suitable for large-scale promotion and application in reclaimed water reuse and industrial circulating water systems.

[0116] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An oxidizing bactericide, characterized in that, By weight, it includes: 30-60 parts of modified chloramine compound, 5-15 parts of modified chelating agent, 3-10 parts of delay agent, 2-8 parts of synergist, 1-5 parts of corrosion inhibitor, and water to a total weight of 100 parts.

2. The oxidizing bactericide according to claim 1, characterized in that, The method for preparing the modified chloramine compound includes: S1. Mix chloramine-B with water, add chloroalkane reagent, and after reaction, obtain crude reactant; S2. The crude reactant is subjected to vacuum distillation and drying to obtain the modified chloramine compound.

3. The oxidizing bactericide according to claim 2, characterized in that, It must include at least one of the following (1) to (6): (1) The weight ratio of chloramine-B to water in step S1 is 1:(2.5~3.5); (2) The molar ratio of chloramine-B and the chloroalkane reagent in step S1 is (1.0~1.5):1; (3) The chloroalkane reagent in step S1 includes any one or a combination of at least two of chloromethane, chloroethane, or chloropropane; (4) The reaction temperature in step S1 is 35~45℃ and the reaction time is 2~4h; (5) The temperature of the vacuum distillation in step S2 is 55~65℃, the time of the vacuum distillation is 2~3h, and the vacuum degree is -0.07~ -0.85MPa; (6) The drying in step S2 includes vacuum drying; the conditions for vacuum drying are: temperature 60~70℃, vacuum degree -0.08 ~ -0.09 MPa, and time 4~6h.

4. The oxidizing bactericide according to claim 1, characterized in that, The modified chelating agent includes modified disodium ethylenediaminetetraacetate and / or modified pentasodium diethylenetriaminepentaacetate; The modification steps of the modified disodium ethylenediaminetetraacetate include: A1. Add activated carbon to an aqueous solution of disodium ethylenediaminetetraacetate, decolorize, and then filter to obtain a purified solution. A2. Add ethylene glycol, glycerol and sodium acetate to the purified solution, stir well, add alkaline reagent to adjust the pH to alkaline, and obtain the reaction product after reaction. A3. The reaction product is subjected to heat treatment to obtain a aging product; A4. After cooling, add an acidic reagent to the ripening product to adjust the pH to neutral, add anhydrous ethanol, stir evenly, and then dry to obtain the modified disodium ethylenediaminetetraacetate. The preparation method of the modified diethylenetriaminepentaacetic acid pentasodium includes: B1. Ethylenediamine was added to an aqueous solution of diethylenetriaminepentaacetate pentasodium, and the crude modified product was obtained after the reaction. B2. The crude modified material is dried to obtain the modified diethylenetriaminepentaacetic acid pentasodium.

5. The oxidizing bactericide according to claim 4, characterized in that, It must include at least one of the following (7) to (23), (7) The mass concentration of the disodium ethylenediaminetetraacetate aqueous solution in step A1 is 20-25%; (8) The amount of activated carbon added in step A1 is 0.3~0.8% of the mass of disodium ethylenediaminetetraacetate; (9) The decolorization treatment time in step A1 is 20~40 min, and the decolorization treatment temperature is 20~40℃; (10) The amount of ethylene glycol added in step A2 is 0.2-1.0% of the mass of disodium ethylenediaminetetraacetate, the amount of glycerol added is 0.1-0.5% of the mass of disodium ethylenediaminetetraacetate, and the amount of sodium acetate added is 0.5-1.5% of the mass of disodium ethylenediaminetetraacetate; (11) The alkaline reagent in step A2 includes a sodium hydroxide solution, wherein the mass concentration of the sodium hydroxide solution is 0.5-5%; (12) The alkalinity mentioned in step A2 refers to a pH of 8.0 to 9.0; (13) The temperature of the reaction in step A2 is 60~70℃ and the reaction time is 2~4h; (14) The temperature of the heat preservation treatment in step A3 is 75~85℃, and the heat preservation treatment time is 1~1.5h; (15) The cooling mentioned in step A4 refers to cooling down to 40~50℃; (16) The acidic reagent in step A4 includes a hydrochloric acid solution, wherein the mass concentration of the hydrochloric acid solution is 3-10%; (17) The neutrality mentioned in step A4 refers to a pH of 6.5 to 7.5; (18) The amount of anhydrous ethanol added in step A4 is 2-4% of the mass of the aging product; (19) The drying in step A4 includes spray drying and / or vacuum drying; the conditions for spray drying are: inlet air temperature 165~175℃, outlet air temperature 80~90℃; the conditions for vacuum drying are: temperature 60~70℃, vacuum degree -0.08~-0.09 MPa, and time 4~6h. (20) The mass concentration of the diethylenetriaminepentaacetic acid pentasodium aqueous solution in step B1 is 20-25%; (21) The molar ratio of diethylenetriaminepentaacetate pentasodium and ethylenediamine in step B1 is 1: (1.3~1.5). (22) The reaction temperature in step B1 is 48~56℃, and the reaction time is 3.5~4.5h; (23) The drying in step B2 includes vacuum drying; the conditions for vacuum drying are: temperature 60~70℃, vacuum degree -0.08 ~ -0.09 MPa, and time 4~6h.

6. The oxidizing bactericide according to claim 1, characterized in that, The delay agent includes any one or a combination of at least two of sodium peroxide, magnesium peroxide, disodium hydrogen phosphate, and sodium dihydrogen phosphate; Preferably, the delay agent is a combination of disodium hydrogen phosphate and sodium dihydrogen phosphate; the mass ratio of disodium hydrogen phosphate to sodium dihydrogen phosphate is 1:(0.8~1.2).

7. The oxidizing bactericide according to claim 1, characterized in that, The synergist includes any one or a combination of at least two of potassium bromide, ammonium chloride, and ammonium sulfate.

8. The oxidizing bactericide according to claim 1, characterized in that, The corrosion inhibitor includes organophosphonate corrosion inhibitors; Preferably, the organophosphonate corrosion inhibitor includes aminotrimethylenephosphonic acid and / or hydroxyethylidene diphosphonic acid.

9. A method for preparing an oxidizing bactericide as described in any one of claims 1 to 8, characterized in that, include: A modified chloramine compound, a modified chelating agent, a delay agent, a synergist, a corrosion inhibitor, and water are mixed evenly to obtain an oxidizing bactericide.

10. The application of an oxidizing bactericide as described in any one of claims 1 to 8, characterized in that, The oxidizing bactericide is used for the sterilization treatment of greywater and / or industrial circulating water, with a dosage of 20~100mg / L.

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