Ultrafiltration membrane cleaning agent and preparation method thereof

Abstract

The present invention belongs to the technical field of semipermeable membrane cleaning, and specifically relates to an ultrafiltration membrane cleaning agent and a preparation method thereof. The ultrafiltration membrane cleaning agent of the present invention comprises component A and component B, wherein component A comprises 10-30 parts of a surfactant, 5-10 parts of a chelating agent, 5-10 parts of a water softener, 80-99 parts of deionized water and a pH regulator by weight; component B comprises 5-12 parts of an oxidant, 10-30 parts of silver nitrate, 5-10 parts of a stabilizer and 80-99 parts of deionized water; wherein the weight ratio of the pH regulator to the chelating agent is (1.1-1.5):1. The ultrafiltration membrane cleaning agent of the present invention can remove various pollutants, especially microorganisms, while causing less damage to the ultrafiltration membrane, having low use cost and little environmental pollution; the present invention also provides a preparation method of an ultrafiltration membrane cleaning agent, which can ensure the stable quality of the cleaning agent, is easy to operate, and is suitable for large-scale production applications.

Description

Technical Field

[0001] The invention belongs to the technical field of semipermeable membrane cleaning, and in particular relates to an ultrafiltration membrane cleaning agent and a preparation method thereof. Background Art

[0002] Ultrafiltration membrane is a microporous membrane with a pore size between 1 and 100 nanometers. As an important separation technology, it has been widely used in water treatment, food, biopharmaceuticals and other fields. Its main function is to separate pollutants such as polysaccharides, lipids, insoluble salts and microorganisms in the mixed liquid to be treated from water through the microporous structure on the membrane surface. However, during use, these pollutants are easily deposited on the surface of the ultrafiltration membrane, resulting in pore blockage, decreased membrane flux and deterioration of separation performance. Therefore, regular cleaning of the ultrafiltration membrane is the key to maintaining its efficient operation.

[0003] At present, the commonly used ultrafiltration membrane cleaning methods include physical cleaning and chemical cleaning. Physical cleaning mainly removes pollutants on the membrane surface by flushing with clean water or air-water combined flushing, but its effect is limited and it is difficult to completely remove stubborn pollutants, especially microorganisms. Chemical cleaning uses chemical reagents to react with pollutants to achieve the purpose of dissolving and stripping pollutants. Common chemical cleaning agents include acidic cleaning agents, alkaline cleaning agents and chelating agents. However, existing chemical cleaning agents have some shortcomings, such as poor cleaning effect on microorganisms, certain corrosiveness to ultrafiltration membranes, and high cost of use.

[0004] Chinese patent CN115591408A discloses an alkaline cleaning agent for ultrafiltration membrane and a preparation method thereof. The alkaline cleaning agent for ultrafiltration membrane is mainly prepared from the following raw materials: by weight, 15 to 25 parts of sodium dodecylbenzene sulfonate, 10 to 25 parts of sodium hexametaphosphate, 5 to 15 parts of sodium EDTA-4, 8 to 10 parts of carboxymethyl cellulose, 5 to 12 parts of sodium tripolyphosphate and 25 to 35 parts of deionized water.

[0005] The patent has the following defects: the alkaline cleaning agent for ultrafiltration membranes described in the patent contains 8 to 10 parts by mass of carboxymethyl cellulose, which is added in a large amount. As a thickener, carboxymethyl cellulose can increase the viscosity of the alkaline cleaning agent for ultrafiltration membranes, so that the alkaline cleaning agent for ultrafiltration membranes is evenly distributed on the surface of the ultrafiltration membrane, reducing the generation of large-volume foam and improving the cleaning effect; however, higher viscosity will also make it easier for surfactants to remain on the surface of the ultrafiltration membrane, making it easier for microorganisms to attach; in addition, the patent uses a large amount of phosphate, and these factors will further promote the reproduction of microorganisms and corrode the ultrafiltration membrane.

[0006] Chinese patent CN103768955A discloses an ultrafiltration membrane cleaning agent, which includes, by weight: 7 to 12 parts of sodium dodecylbenzene sulfonate, 5 to 8 parts of sodium fatty alcohol polyoxyethylene ether sulfonate, 2 to 6 parts of carboxymethyl cellulose, 3 to 9 parts of sodium citrate, 1 to 4 parts of sodium carbonate, 2 to 8 parts of sodium hydroxide, 0.1 to 0.6 parts of pectinase, 1 to 7 parts of aliphatic polyoxyethylene ether, and 0.5 to 1.9 parts of potassium silicate.

[0007] This patent has the following disadvantages: sodium dodecylbenzene sulfonate, sodium fatty alcohol polyoxyethylene ether sulfonate and aliphatic polyoxyethylene ether in this patent are all surfactants, and other components cannot chelate heavy metal ions, which will result in poor removal of heavy metal ions; on the other hand, heavy metal ions remaining on the surface of the ultrafiltration membrane will combine with the active center of pectinase and thus cause pectinase inactivation, affecting the effect of pectinase in inhibiting microbial reproduction; in addition, the storage conditions of pectinase are relatively harsh, and high temperature and humidity or long storage time will cause pectinase activity to be impaired.

[0008] In order to solve the above problems in the prior art, it is particularly important to develop a new type of ultrafiltration membrane cleaning agent and a preparation method thereof. Summary of the invention

[0009] The object of the present invention is to provide an ultrafiltration membrane cleaning agent, which has high-efficiency cleaning ability, can effectively remove various pollutants, especially microorganisms, and at the same time causes little damage to the ultrafiltration membrane, has low use cost, and has little pollution to the environment; the present invention also provides a preparation method of the ultrafiltration membrane cleaning agent, which can ensure the stable quality of the cleaning agent, is easy to operate, and is suitable for large-scale production applications.

[0010] To achieve the above object, the technical solution adopted by the present invention is:

[0011] The ultrafiltration membrane cleaning agent of the present invention comprises component A and component B. In terms of weight, component A comprises 10-30 parts of a surfactant, 5-10 parts of a chelating agent, 5-10 parts of a water softener, 80-99 parts of deionized water and a pH regulator; component B comprises 5-12 parts of an oxidant, 10-30 parts of silver nitrate, 5-10 parts of a stabilizer and 80-99 parts of deionized water; wherein the weight ratio of the pH regulator to the chelating agent is (1.1-1.5):1.

[0012] in:

[0013] The surfactant is prepared by compounding octadecyl dihydroxyethyl amine oxide, xanthan gum, sodium dodecyl sulfate and N,N-dimethylacetamide in a weight ratio of (5-12): (1-3): 1: (2-7).

[0014] Octadecyl dihydroxyethylamine oxide is a nonionic surfactant with excellent detergency and can adjust the fineness and stability of foam; sodium dodecyl sulfate is an anionic surfactant with strong foaming, emulsifying and dispersing properties; N,N-dimethylacetamide is a nonionic solvent with good solubility and permeability. By compounding in the optimal ratio, the emulsification, dispersibility and permeability of surfactants can be improved, and the surfactant residue can be reduced and the decontamination efficiency can be improved.

[0015] The chelating agent is ethylenediaminetetraacetic acid or diethyltriaminepentaacetic acid.

[0016] The water softener is sodium phosphate or sodium silicate.

[0017] The pH regulator is sodium hydroxide or sodium bicarbonate.

[0018] The oxidant is hydrogen peroxide. Compared with strong oxidants such as potassium permanganate, hydrogen peroxide has moderate oxidation ability, which can not only prevent silver nitrate from being oxidized during long-term storage, but also assist silver nitrate in removing microorganisms. At the same time, moderate oxidizing property also reduces damage to ultrafiltration membranes.

[0019] The stabilizer is prepared by compounding hydroxyethylidene diphosphonic acid and potassium sorbate in a weight ratio of (2-6):1.

[0020] Hydroxyethylidene diphosphonic acid can be used as a peroxide stabilizer. Its combination with potassium sorbate can significantly improve the chemical stability of ultrafiltration membrane cleaning agents and prevent them from deteriorating during storage and use, thereby ensuring the cleaning effect and extending the service life of the cleaning agent.

[0021] The preparation method of the ultrafiltration membrane cleaning agent comprises the following steps:

[0022] a): Stirring a surfactant, a chelating agent, a water softener and deionized water, and adding a pH regulator to adjust the pH value to obtain component A;

[0023] b): fully mix the oxidant, silver nitrate, stabilizer and deionized water, and stir evenly under heating to obtain component B;

[0024] c): When in use, component A and component B are compounded to prepare an ultrafiltration membrane cleaning agent.

[0025] in:

[0026] In the step a), the stirring temperature is 40-80°C, the stirring time is 40-60min, the stirring rate is 100-300rpm; and the pH value is 7.5-9.

[0027] In the step b), the heating temperature is 50-70° C. and the stirring rate is 100-300 rpm.

[0028] In the step c), component A and component B are compounded in a weight ratio of (1-2.2):1.

[0029] The beneficial effects of the present invention are as follows:

[0030] 1. Different components are stored separately to improve the stability of ultrafiltration membrane cleaning agent during long-term storage:

[0031] If component A and component B are mixed together and stored for a long time, the empty orbital of the outer layer of the silver ion in silver nitrate will form an insoluble coordination complex with the lone pair of electrons on the chelating agent or surfactant. This complex will adhere to the inner wall of the storage container, affecting the uniformity and subsequent use of the ultrafiltration membrane cleaning agent. Therefore, the surfactant and chelating agent and other raw materials are separately prepared into component A; and silver nitrate is separated from component A, and oxidants, stabilizers and other raw materials are added to prepare component B, which effectively prevents silver nitrate from deliquescence, oxidation or deterioration during long-term storage.

[0032] 2. The combination of component A and component B can remove most types of pollutants and achieve a more thorough cleaning effect:

[0033] Chelating agents are mainly used to remove inorganic salt pollutants. They can chelate metal ions to form insoluble complexes and then remove inorganic salt pollutants. Oxidants and silver nitrate focus on removing microorganisms. They can destroy the cell structure of microorganisms to achieve the effect of sterilization and disinfection. Surfactants mainly remove oily pollutants. They have a significant emulsifying effect on lipids and can emulsify oily pollutants into tiny droplets, which is convenient for cleaning and removal. At the same time, they also play a role in improving the wettability of ultrafiltration membrane cleaning agents and can enhance the contact between ultrafiltration membrane cleaning agents and pollutants on the membrane surface. This allows ultrafiltration membrane cleaning agents to more effectively penetrate into the tiny pores and folds on the membrane surface, fully contact and react with pollutants, thereby improving the cleaning effect. The combination of chelating agents, oxidants, silver nitrates and surfactants can comprehensively remove different types of pollutants.

[0034] 3. Compound xanthan gum with octadecyl dihydroxyethylamine oxide, sodium lauryl sulfate and N,N-dimethylacetamide in a certain proportion to effectively exert the synergistic effect of xanthan gum on the components in the surfactant:

[0035] Sodium dodecyl sulfate is a strong foaming agent that can produce a large amount of foam, while octadecyl dihydroxyethylamine oxide can adjust the fineness and stability of the foam. N,N-dimethylacetamide, as a non-ionic solvent, can improve the fluidity of the system and help the uniform mixing of the components, ultimately helping to form stable and fine foam. Since the foam is stable and not easy to break, it can stay on the surface of the ultrafiltration membrane for a longer time. The fine foam has a larger specific surface area, so the foam can penetrate into the tiny pores on the surface of the ultrafiltration membrane and effectively and comprehensively remove surface pollutants.

[0036] The high molecular chain of xanthan gum will be entangled with octadecyl dihydroxyethylamine oxide and sodium dodecyl sulfate in water to form a three-dimensional network structure. This network structure can wrap the oil particles, facilitate the subsequent cleaning of the oil and three-dimensional network structure, reduce the surfactant residue on the surface of the ultrafiltration membrane, and thus reduce membrane damage.

[0037] At the same time, the hydrophilic groups such as hydroxyl and carboxyl groups on the xanthan gum molecules form a hydrogen bond network structure with the hydrophilic parts of octadecyl dihydroxyethylamine oxide and sodium dodecyl sulfate and water molecules, which makes the surfactant molecules more orderly and tightly arranged on the surface of the oil particles to form an interface film. This orderly arrangement not only enhances the stability of the interface film, but also makes the interface film more uniform and continuous, thereby more effectively reducing the surface tension between water and oil and improving the decontamination effect; the hydrogen bond network structure can also play a guiding role, making it easier for oil particles and surfactant molecules to collide. Since xanthan gum itself has a thickening effect, this slows down the movement of oil particles and surfactant molecules, and the relative distance between them is further shortened. This shortened distance increases the chance of collision between them, thereby improving the decontamination efficiency.

[0038] 4. Compounding sodium dodecyl sulfate with chelating agent ethylenediaminetetraacetic acid (EDTA) or diethyltriaminepentaacetic acid (DTPA) can effectively exert its own properties and synergistic effects:

[0039] The carboxyl group of EDTA (or DTPA) will partially dissociate into carboxylate ions in component A, which will form reversible ion pairs with the sulfate ions of sodium dodecyl sulfate in component A, thereby changing the arrangement of sodium dodecyl sulfate molecules at the oil-water interface. Specifically, the EDTA molecule (or DTPA molecule) itself acts as an anchor point to connect the sodium dodecyl sulfate molecules more tightly together, forming a more ordered, tighter, and more stable arrangement layer at the oil-water interface. On the one hand, this arrangement reduces the collision and merging between oil droplets, prevents the desorption of surfactant molecules from the oil-water interface, improves the stability of the emulsion, facilitates subsequent cleaning and decontamination, and prevents surfactants from remaining on the surface of the ultrafiltration membrane. On the other hand, the tightly arranged molecular layer can more effectively reduce the surface energy of the ultrafiltration membrane surface and promote the wetting process.

[0040] 5. The use of chelating agents in combination with silver nitrate can bring out the synergistic effect of the two: the empty orbits on the outer orbits of silver ions will form coordination complexes with the lone pair of electrons on the chelating agent, preventing the silver ions from losing their activity due to hydrolysis. In addition, the complexes can more easily penetrate the cell walls of microorganisms, improving the sterilization efficiency; in addition, by combining with chelating agents, silver ions are fixed in the coordination complexes, reducing their direct exposure to the environment, thereby reducing their toxicity and being more environmentally friendly.

[0041] 6. The present invention uses a variety of components in combination to effectively remove most types of pollutants; no strong oxidants are used, and the components in the ultrafiltration membrane cleaning agent are not easy to remain on the surface of the ultrafiltration membrane, thereby reducing membrane damage; in addition, the raw materials are easy to obtain, and the preparation is simple, including only basic compounding, mixing and other steps; there is no need to use complex processing equipment, the cost is low, the long-term storage stability is good, and the shelf life is long. DETAILED DESCRIPTION

[0042] The present invention is specifically described and illustrated below in conjunction with embodiments.

[0043] Example 1

[0044] First, octadecyl dihydroxyethyl amine oxide, xanthan gum, sodium dodecyl sulfate and N,N-dimethylacetamide are compounded in a weight ratio of 7:2:1:2 to obtain 20 kg of a surfactant; then, 20 kg of a surfactant, 5 kg of ethylenediaminetetraacetic acid, 5 kg of sodium phosphate and 90 kg of deionized water are added to a first reactor, the hot water jacket of the first reactor is opened and stirring is started, the stirring speed is set to 100 rpm, and the mixture is stirred evenly at 60°C, and then 7.5 kg of sodium hydroxide is added, and the pH is adjusted to 9 to obtain component A.

[0045] First, hydroxyethylidene diphosphonic acid and potassium sorbate are compounded in a weight ratio of 2:1 to obtain a stabilizer; then, 5 kg of hydrogen peroxide, 10 kg of silver nitrate, 5 kg of stabilizer and 90 kg of deionized water are added to the second reactor, the hot water jacket of the second reactor is opened and stirring is started, the stirring speed is set to 100 rpm, and stirring is carried out evenly at 70°C to obtain component B.

[0046] Label components A and B and store them separately in a dry and dark place. When in use, mix components A and B in a mass ratio of 1:1 to form an ultrafiltration membrane cleaning agent.

[0047] Example 2

[0048] First, octadecyl dihydroxyethylamine oxide, xanthan gum, sodium dodecyl sulfate and N,N-dimethylacetamide are compounded in a weight ratio of 5:1:1:5 to prepare 10 kg of surfactant; then, 10 kg of surfactant, 10 kg of diethyltriamine pentaacetic acid, 10 kg of sodium silicate and 80 kg of deionized water are added to the first reactor and mixed, the hot water jacket of the first reactor is opened and stirring is started, the stirring speed is set to 200 rpm, and the mixture is stirred evenly at 80°C, and then 13 kg of sodium bicarbonate is added, and the pH is adjusted to 8 to obtain component A.

[0049] First, hydroxyethylidene diphosphonic acid and potassium sorbate are compounded in a weight ratio of 6:1 to obtain a stabilizer; then, 12 kg of hydrogen peroxide, 30 kg of silver nitrate, 10 kg of stabilizer and 80 kg of deionized water are added to the second reactor, the hot water jacket of the second reactor is opened and stirring is started, the stirring speed is set to 200 rpm, and stirring is carried out evenly at 60° C. to obtain component B.

[0050] Label components A and B and store them separately in a dry and dark place. When in use, mix components A and B in a mass ratio of 1.6:1 to form an ultrafiltration membrane cleaning agent.

[0051] Example 3

[0052] First, octadecyl dihydroxyethylamine oxide, xanthan gum, sodium dodecyl sulfate and N,N-dimethylacetamide are compounded in a weight ratio of 12:3:2:7 to obtain 30 kg of a surfactant; then, 30 kg of a surfactant, 8 kg of diethyltriamine pentaacetic acid, 8 kg of sodium phosphate and 99 kg of deionized water are added to a first reactor and mixed, the hot water jacket of the first reactor is opened and stirring is started, the stirring speed is set to 300 rpm, and stirring is performed evenly at a temperature of 40°C, and then 8.8 kg of sodium hydroxide is added, and the pH is adjusted to 7.5 to obtain component A.

[0053] First, hydroxyethylidene diphosphonic acid and potassium sorbate were compounded in a weight ratio of 4:1 to obtain a stabilizer; then, 9 kg of hydrogen peroxide, 25 kg of silver nitrate, 8 kg of stabilizer and 99 kg of deionized water were added to the second reactor, the hot water jacket of the second reactor was opened and stirring was started, the stirring speed was set to 300 rpm, and the mixture was stirred evenly at 50°C to obtain component B.

[0054] Label components A and B and store them separately in a dry and dark place. When in use, mix components A and B in a mass ratio of 2.2:1 to form an ultrafiltration membrane cleaning agent.

[0055] Comparative Example 1

[0056] No sodium lauryl sulfate was added to the surfactant, and the remaining steps were the same as in Example 1.

[0057] Comparative Example 2

[0058] No xanthan gum was added to the surfactant, and the remaining steps were the same as those in Example 1.

[0059] Comparative Example 3

[0060] No chelating agent was added to component A, and the remaining steps were the same as those in Example 1.

[0061] Comparative Example 4

[0062] The oxidant is prepared by mixing potassium permanganate and 55 wt % hydrochloric acid in a weight ratio of 1:1, and is used to replace hydrogen peroxide. The remaining steps are the same as those in Example 1.

[0063] Comparative Example 5

[0064] The A and B components were compounded into an ultrafiltration membrane cleaning agent in a mass ratio of 1:1, labeled, and stored in a dry and dark place for 4 months. The remaining steps were the same as in Example 1.

[0065] The effects of the ultrafiltration membrane cleaning agents prepared in the examples and comparative examples were evaluated:

[0066] (1) A conventional ultrafiltration membrane filtration device that has been used for 80 days is selected. The ultrafiltration membrane filtration device is mainly used for post-treatment of wastewater in the production process of chromate dyes. The wastewater contains impurities such as heavy metal ions such as chromium, organic waste solvents, acidic substances, suspended particles and microorganisms. The ultrafiltration membrane filtration device includes an ultrafiltration membrane assembly, a pressure system, a circulation system, a cleaning system, etc. The ultrafiltration membrane assembly includes primary, secondary, tertiary and quaternary ultrafiltration membranes. The pure water flux performance index of the primary ultrafiltration membrane is 553L / (m 2 ·h). First, record the transmembrane pressure difference and pure water flux of the first-stage ultrafiltration membrane before cleaning (i.e. after normal use). It is required that the transmembrane pressure difference of the first-stage ultrafiltration membrane after cleaning is ≤0.15MPa, and the pure water flux is ≥530L / (m 2 ·h), see Table 1 for specific data.

[0067] After that, the ultrafiltration membrane filtration device was shut down, emptied and cleaned, and finally the first-stage ultrafiltration membrane was taken out, and the first-stage ultrafiltration membrane was cut into 8 samples of the same size. The ultrafiltration membrane cleaning agents described in Examples 1-3 and Comparative Examples 1-5 of the same weight were used as cleaning liquids, and the samples were immersed in 8 portions of the cleaning liquids in an upright manner, and the cleaning liquids were circulated on both sides of the sample inside and outside for 20 minutes; then the sample was taken out, rinsed with clean water to remove the residual cleaning liquid, and the transmembrane pressure difference (MPa) and pure water flux (L / (m 2 ·h)), see Table 1 for specific data.

[0068] (2) Before using the cleaning solution, use a sterile cotton swab to gently scrape 5 locations on each sample, and then put it into a sterile dilution bottle and add agar aqueous solution to dilute it to obtain a dilution solution. Then, spread the dilution solution evenly on the culture dish; put the culture dish in a constant temperature incubator and incubate it at 30℃ for 72 hours, then take it out and observe and record the number of colonies on the culture dish.

[0069] After cleaning with cleaning solution, use sterile cotton swabs to gently scrape the same five locations on each sample. The culture steps are the same as step (2). Observe and record the number of colonies on the culture dish to determine the microbial removal rate (%). The specific data are shown in Table 1.

[0070]

[0071] In Comparative Example 1, sodium lauryl sulfate is not added, that is, a synergistic system of sodium lauryl sulfate and a chelating agent cannot be formed; in Comparative Example 2, xanthan gum is not added, that is, a synergistic system of a surfactant compound is not formed; in Comparative Example 3, a chelating agent is not added, that is, a synergistic system of sodium lauryl sulfate and a chelating agent cannot be formed, and a synergistic effect of the chelating agent and silver nitrate cannot be produced; in Comparative Example 4, a strong oxidant is used instead of hydrogen peroxide with moderate oxidizing property; in Comparative Example 5, components A and B are mixed and stored, that is, silver nitrate is not stored separately from the surfactant and the chelating agent for a long time.

[0072] According to the data in Table 1, the transmembrane pressure difference of the first-stage ultrafiltration membrane after cleaning in Examples 1-3 is ≤0.10MPa, and the pure water flux is ≥547L / (m 2 ·h), indicating that the ultrafiltration membrane cleaning agent of the present invention has a good cleaning effect and can remove most of the pollutants, especially the removal rate of microorganisms is above 92%; compared with the original pure water flux performance index of the first-stage ultrafiltration membrane, the pure water flux after cleaning does not change much, which means that the membrane structure is basically not damaged after cleaning, the transmembrane pressure difference and pure water flux parameters of the ultrafiltration membrane basically meet the cleaning requirements, and the ultrafiltration membrane can continue to be used.

[0073] However, after cleaning with the ultrafiltration membrane cleaning agent prepared in Comparative Examples 1-5, the transmembrane pressure difference of the ultrafiltration membrane is still large and the pure water flux is small. The reason is that the cleaning effect is not good and some pollutants are not completely removed; the ultrafiltration membrane is severely damaged during cleaning, resulting in damage to the pore structure of the ultrafiltration membrane.

Claims

1. An ultrafiltration membrane cleaning agent, characterized in that: The invention comprises component A and component B, wherein, by weight, component A comprises 10-30 parts of a surfactant, 5-10 parts of a chelating agent, 5-10 parts of a water softener, 80-99 parts of deionized water and a pH regulator; component B comprises 5-12 parts of an oxidant, 10-30 parts of silver nitrate, 5-10 parts of a stabilizer and 80-99 parts of deionized water; wherein the weight ratio of the pH regulator to the chelating agent is (1.1-1.5):1; The surfactant is prepared from octadecyl dihydroxyethyl amine oxide, xanthan gum, sodium dodecyl sulfate and N,N-dimethylacetamide; the oxidant is hydrogen peroxide.

2. The ultrafiltration membrane cleaning agent according to claim 1, characterized in that The surfactant is prepared by compounding octadecyl dihydroxyethyl amine oxide, xanthan gum, sodium dodecyl sulfate and N,N-dimethylacetamide in a weight ratio of (5-12):(1-3):1:(2-7).

3. The ultrafiltration membrane cleaning agent according to claim 1, characterized in that The chelating agent is ethylenediaminetetraacetic acid or diethyltriaminepentaacetic acid.

4. The ultrafiltration membrane cleaning agent according to claim 1, characterized in that Water softeners are sodium phosphate or sodium silicate.

5. The ultrafiltration membrane cleaning agent according to claim 1, characterized in that The pH adjuster is sodium hydroxide or sodium bicarbonate.

6. The ultrafiltration membrane cleaning agent according to claim 1, characterized in that The stabilizer is prepared by compounding hydroxyethylidene diphosphonic acid and potassium sorbate in a weight ratio of (2-6):

1.

7. A method for preparing the ultrafiltration membrane cleaning agent according to any one of claims 1 to 6, characterized in that: The following steps are involved: a): Stirring a surfactant, a chelating agent, a water softener and deionized water, and adding a pH regulator to adjust the pH value to obtain component A; b): fully mix the oxidant, silver nitrate, stabilizer and deionized water, and stir evenly under heating to obtain component B; c): When in use, component A and component B are compounded to prepare an ultrafiltration membrane cleaning agent.

8. The method for preparing the ultrafiltration membrane cleaning agent according to claim 7, characterized in that: In step a), the stirring temperature is 40-80° C., the stirring time is 40-60 min, the stirring rate is 100-300 rpm, and the pH value is 7.5-9.

9. The method for preparing the ultrafiltration membrane cleaning agent according to claim 7, characterized in that: In step b), the heating temperature is 50-70° C. and the stirring rate is 100-300 rpm.

10. The method for preparing the ultrafiltration membrane cleaning agent according to claim 7, characterized in that: In step c), component A and component B are compounded in a weight ratio of (1-2.2):1.

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