A membrane cleaning agent and methods of making and using the same

Abstract

The application relates to a membrane cleaning agent and a preparation and use method thereof, the membrane cleaning agent comprising a first cleaning agent and a second cleaning agent with a mass ratio of 1:(1.6-1.9); the first cleaning agent comprises the following components and contents: 20-24% of a cleaning agent, 10-16% of a penetrating agent, 3-5% of a non-silicon defoaming agent, and the balance being water; the cleaning agent comprises a treatment enzyme and an oxidizing agent with a mass ratio of 1:(0.4-0.6); the second cleaning agent comprises the following components and contents: 1-5% of an inorganic alkali regulator, 5-10% of a surfactant, 10-12% of a bactericide, 10-12% of a dispersing agent, 3-5% of a non-silicon defoaming agent, and the balance being water; the inorganic alkali cleaning agent comprises a hydroxide and a carbonate with a mass ratio of 1:(0.6-0.8). The application can improve the cleaning effect on the accumulated dirt and blockage on a reverse osmosis membrane.

Description

Technical Field

[0001] This application relates to the field of membrane cleaning agents, and in particular to a membrane cleaning agent and its preparation and application methods. Background Technology

[0002] Reverse osmosis, also known as reverse osmosis, is a membrane separation process that uses a pressure difference to separate the solvent from the solution. It is commonly used in membrane-based wastewater treatment systems. The reverse osmosis membrane is an artificial semi-permeable membrane with specific properties, mimicking a biological semi-permeable membrane, and is the core component of a reverse osmosis unit. The principle of reverse osmosis technology is based on the principle that under pressure higher than the osmotic pressure of the solution, other substances cannot pass through the reverse osmosis membrane, thus separating them from water and effectively removing dissolved salts, colloids, microorganisms, organic matter, etc. from the water.

[0003] However, during the wastewater separation and treatment process, after a period of operation, the reverse osmosis unit accumulates substances such as colloids, metal oxides, bacteria, organic matter, or scale on the concentrate side of the reverse osmosis membrane, leading to membrane fouling. This results in problems such as decreased system desalination rate, reduced permeate flow, and increased pressure differential. Timely and effective cleaning of the reverse osmosis membrane surface is crucial for alleviating operational pressure and preventing further deterioration; therefore, the selection of the appropriate membrane cleaning agent is essential.

[0004] Currently, for a range of organic and microbial fouling substances, a cleaning agent is typically formed by combining alkali and surfactant. The alkali and surfactant can loosen, emulsify, and disperse the organic and microbial fouling substances relative to the reverse osmosis membrane, thereby achieving the cleaning of the reverse osmosis membrane.

[0005] Reverse osmosis membranes accumulate biological contaminants such as proteins and algae, colloidal contaminants, and most organic contaminants such as oils. During membrane separation, these contaminant particles interact mechanically or physically with the reverse osmosis membrane, causing them to be firmly adsorbed and deposited on the membrane surface or within the membrane pores. Therefore, the cleaning effect achieved by simply loosening, emulsifying, and dispersing the contaminant particles with alkali and surfactants needs to be improved. Summary of the Invention

[0006] To improve the cleaning effect on fouling deposits accumulated on reverse osmosis membranes, this application provides a membrane cleaning agent and its preparation and application methods.

[0007] The membrane cleaning agent provided in this application adopts the following technical solution: A membrane cleaning agent comprising a first cleaning agent and a second cleaning agent in a mass ratio of 1:(1.6-1.9); The first detergent comprises the following components and their contents: 20-24% detergent builder, 10-16% penetrant, 3-5% non-silicone defoamer, and the balance being water; The detergent additive comprises a treatment enzyme and an oxidant in a mass ratio of 1:(0.4-0.6); The second detergent comprises the following components and their contents: 1-5% inorganic alkali regulator, 5-10% surfactant, 10-12% bactericide, 10-12% dispersant, 3-5% non-silicone defoamer, and the balance being water; The inorganic alkaline detergent comprises hydroxide and carbonate in a mass ratio of 1:(0.6-0.8).

[0008] By employing the above technical solution, when cleaning the reverse osmosis membrane, the membrane is first circulated and cleaned using a cleaning solution prepared with a first cleaning agent. The processing enzymes decompose biofouling substances such as colloids and proteins on the reverse osmosis membrane, while the oxidant oxidizes these biofouling substances and organic matter such as grease, causing them to denature and detach from the membrane surface. This disrupts the mechanical or physicochemical interactions between the fouling particles and the reverse osmosis membrane, loosening or even detaching the fouling particles from the membrane surface. The penetrant allows the processing enzymes and oxidant to penetrate more fully into the fouling substances, enhancing their decomposition and oxidative denaturation effects.

[0009] Furthermore, since the treatment enzyme itself is also a protein, it can adsorb onto the membrane surface and the inner wall of the membrane pores under improper pH conditions, forming new fouling. However, by using the treatment enzyme and oxidant in combination, the oxidant can also cause the treatment enzyme to undergo oxidative denaturation at a specific water temperature during use, thereby reducing the possibility of the treatment enzyme adhering to the membrane surface and the inner wall of the membrane pores and forming new fouling.

[0010] After the biological and organic fouling on the reverse osmosis membrane is decomposed and oxidized by enzymes and oxidants, the membrane is then cleaned a second time using a cleaning solution prepared with the first cleaning agent. The combined use of hydroxides and carbonates creates a stable alkaline solution environment in the cleaning solution. In this alkaline environment, surfactants better promote the loosening, emulsification, and dispersion of fouling particles, while dispersants further prevent the loosened and emulsified fouling particles from agglomerating and depositing, thus further enhancing the cleaning effect on the reverse osmosis membrane.

[0011] The first cleaning agent decomposes and oxidizes biological and organic fouling, effectively disrupting the connection between fouling particles and the reverse osmosis membrane. The second cleaning agent then emulsifies and disperses the fouling particles, further improving the removal of fouling from the reverse osmosis membrane and enhancing the cleaning effect.

[0012] Optionally, the processing enzymes include proteases, cellulases, hemicellulases, pectinases, and gelling enzymes in a mass ratio of 1:(0.3-0.5):(0.1-0.2):(0.2-0.4):(0.6-0.8).

[0013] By adopting the above technical solution and mixing the various enzymes in the above proportions, it is possible to fully and comprehensively decompose biological fouling substances such as proteins and colloids on the reverse osmosis membrane, thereby improving the cleaning effect of the reverse osmosis membrane.

[0014] Optionally, the oxidant is selected from at least one of hydrogen peroxide, peracetic acid, and sodium dichromate.

[0015] By adopting the above technical solution, all of the above oxidants are acidic oxidants. When the above oxidants carry out redox reactions, the solution environment will tend to be acidic, which can make the activity of the processing enzyme better, so as to further enhance the decomposition effect of the processing enzyme on the blockage.

[0016] Optionally, the surfactant is selected from at least one of ethylenediaminetetraacetic acid tetrasodium salt, sodium dodecylbenzenesulfonate, sodium alkyl polyoxyethylene ether sulfate, and sodium oleoylmethyl taurate.

[0017] By adopting the above technical solutions, the surfactants mentioned above all have excellent emulsifying and dispersing abilities, and all of the surfactants mentioned above are alkali-resistant and can play a normal emulsifying and dispersing role in alkaline solution environments.

[0018] Optionally, the bactericide comprises a paraben, an organic bromine and an alcohol solvent in a mass ratio of 1:(0.4-0.6):(2-4).

[0019] By adopting the above technical solutions, parabens and organic bromine are both highly efficient and low-toxic bactericides. Both parabens and organic bromine can destroy cell membranes, causing denaturation of intracellular proteins. In addition, parabens can also inhibit the activity of respiratory enzymes and electron transport enzymes in microbial cells. The combination of the two can more effectively inhibit bacteria and fungi, thereby reducing the possibility of algae growth on reverse osmosis membranes.

[0020] Optionally, the penetrant is selected from at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and sodium aminosulfonate.

[0021] Optionally, the dispersant includes at least one of a sulfonic acid-containing phosphonocarboxylic acid copolymer and hydrolyzed polymaleic anhydride.

[0022] By adopting the above technical solutions, the above dispersants all have excellent scale inhibition and dispersion effects. They can not only prevent the aggregation of microorganisms and organic fouling particles, but also chelate and inhibit the dispersion of easily oxidized metal particles, thereby further improving the cleaning effect on reverse osmosis membranes.

[0023] Optionally, the non-silicone defoamer is selected from at least one of fatty acid glycerides, trialkyl melamine, dialkyl phosphates, and palmitic acid.

[0024] By adopting the above technical solution, the above defoamers are all free of silicon, which ensures that a large number of bubbles are not generated during the preparation of the first and second cleaning agents, and also prevents the formation of silicon scale on the reverse osmosis membrane after cleaning due to the presence of silicon-containing compounds.

[0025] Secondly, the preparation method of the membrane cleaning agent provided in this application adopts the following technical solution: A method for preparing a membrane cleaning agent includes the following steps: The detergent, penetrant, non-silicone defoamer and water in the above-mentioned amounts are mixed and stirred evenly to obtain the first detergent; the inorganic alkaline detergent, surfactant, bactericide, dispersant, non-silicone defoamer and water in the above-mentioned amounts are mixed and stirred evenly to obtain the second detergent. The first detergent and the second detergent are separated and packaged to obtain a membrane cleaning agent, wherein the mass ratio of the first detergent and the second detergent is 1:(1.6-1.9).

[0026] Thirdly, the method of using the membrane cleaning agent provided in this application adopts the following technical solution: A method for using a membrane cleaning agent includes the following steps: Add the first detergent to water, with a mass ratio of the first detergent to water of 1:(90-110), heat to 30-35℃, and open the valve to perform the first circulation cleaning; After the first cycle cleaning is completed, the second detergent is added to the water at a mass ratio of 1:(90-110). The water is heated to 40-50°C, and the valve is opened to perform the second cycle cleaning.

[0027] By employing the above technical solution, the first and second cleaning agents are mixed with water and prepared separately. In a solution environment of 30-35℃, the processing enzymes in the first cleaning agent can better decompose microbial fouling. Subsequently, the second cleaning agent cleaning solution at 40-50℃ is circulated for cleaning. As the temperature and pH increase, the residual oxidant on the reverse osmosis membrane can cause the residual processing enzymes to undergo oxidative denaturation. Furthermore, some processing enzymes also begin to denature and become inactive in a high pH environment. This allows for the emulsification and dispersion of fouling while simultaneously washing away and removing the residual processing enzymes from the reverse osmosis membrane, thereby reducing the possibility of new fouling forming on the reverse osmosis membrane.

[0028] In summary, this application includes at least one of the following beneficial technical effects: 1. The first cleaning agent decomposes and oxidizes biological and organic fouling, effectively disrupting the connection between fouling particles and the reverse osmosis membrane. The second cleaning agent then emulsifies and disperses the fouling particles, further improving the removal of fouling from the reverse osmosis membrane and enhancing cleaning efficiency. 2. Parabens and organic bromine are both highly effective and low-toxicity bactericides. Both can damage cell membranes, causing protein denaturation. Parabens can also inhibit the activity of respiratory and electron transport enzymes in microbial cells. Combining these two agents can more effectively inhibit bacteria and fungi, thus reducing the possibility of algae growth on the reverse osmosis membrane. 3. The defoamers are all silicone-free, which prevents the generation of a large number of bubbles during the preparation of the first and second cleaning agents, and also prevents the formation of silicone scale on the reverse osmosis membrane after cleaning due to the presence of silicone compounds. Detailed Implementation

[0029] I. Implementation Examples Example 1: A membrane cleaning agent comprising a first cleaning agent and a second cleaning agent.

[0030] The first detergent comprises the following components and their amounts: 20% builder, 10% penetrant, 3% non-silicone defoamer, and the remainder is water; The detergent builder includes a treatment enzyme and an oxidizing agent in a mass ratio of 1:0.5; The processing enzymes include protease, cellulase, hemicellulase, pectinase, and gelling enzyme in a mass ratio of 1:0.4:0.15:0.3:0.7. The oxidant is hydrogen peroxide, the penetrant is fatty alcohol polyoxyethylene ether, and the non-silicone defoamer is trialkyl melamine.

[0031] The second detergent comprises the following components and their contents: 1% inorganic alkali regulator, 5% surfactant, 10% bactericide, 10% dispersant, 3% non-silicone defoamer, and the balance is water; The inorganic alkaline detergent consists of hydroxide and carbonate in a mass ratio of 1:0.7; The bactericide includes parabens, organic bromine and alcohol solvent in a mass ratio of 1:0.5:3, wherein the organic bromine is 2,2-dibromo-3-hypopropanamide and the alcohol solvent is 3-propanediol. The surfactant is tetrasodium ethylenediaminetetraacetate, the dispersant is hydrolyzed polymaleic anhydride, and the non-silicone defoamer is dialkyl phosphate.

[0032] Preparation of membrane cleaning agent: 2 kg of detergent builder, 1 kg of fatty alcohol polyoxyethylene ether, 0.3 kg of trialkyl melamine and 6.7 kg of water were mixed and stirred evenly to obtain the first detergent. 0.18 kg of inorganic alkaline detergent, 0.9 kg of tetrasodium ethylenediaminetetraacetate, 1.8 kg of bactericide, 1.8 kg of hydrolyzed polymaleic anhydride, 0.54 kg of dialkyl phosphate and water are mixed and stirred evenly to obtain the second detergent. The first and second detergents are packaged separately to obtain a membrane cleaning agent. The mass of the first detergent is 10 kg, and the mass of the second detergent is 18 kg. The mass ratio of the first detergent to the second detergent is 1:1.7.

[0033] Use of membrane cleaning agent: Fill the cleaning water tank to 1m. 3 Add the prepared first cleaning agent, with a mass ratio of the first cleaning agent to water of 1:100, heat to 35°C, open the valve to perform the first circulation cleaning of the reverse osmosis membrane, and the cleaning time is 6 hours. After the first cycle of cleaning is complete, fill the cleaning water tank to 1.7m. 3 Add the prepared second cleaning agent, heat to 45°C, open the valve to perform a second cycle cleaning of the reverse osmosis membrane, and the cleaning time is 18 hours.

[0034] Examples 2-3: A membrane cleaning agent, which differs from that of Example 1, is shown in Table 1.

[0035] Table 1: Examples 4-5: A membrane cleaning agent, which differs from that of Example 2, is shown in Table 2.

[0036] Table 2: Example 6: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of the first cleaning agent to the second cleaning agent is 1:1.6.

[0037] Example 7: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of the first cleaning agent to the second cleaning agent is 1:1.9.

[0038] Example 8: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of the treating enzyme and the oxidant in the cleaning aid is 1:0.4.

[0039] Example 9: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of the treating enzyme and the oxidant in the cleaning aid is 1:0.6.

[0040] Example 10: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of protease, cellulase, hemicellulase, pectinase and gelase in the treatment enzyme is 1:0.3:0.1:0.2:0.6.

[0041] Example 11: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of protease, cellulase, hemicellulase, pectinase and gelase in the treatment enzyme is 1:0.5:0.2:0.4:0.8.

[0042] Example 12: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of p-hydroxybenzoate, 2,2-dibromo-3-nitropropamide and 3-propanediol in the bactericide is 1:0.4:2.

[0043] Example 13: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of p-hydroxybenzoate, 2,2-dibromo-3-nitropropamide and 3-propanediol in the bactericide is 1:0.6:4.

[0044] Example 14: A membrane cleaning agent differs from that in Example 4 in that, during use, the mass ratio of the first cleaning agent to water is 1:90, and the mass ratio of the second cleaning agent to water is also 1:90.

[0045] Example 15: A membrane cleaning agent differs from Example 4 in that, during use, the mass ratio of the first cleaning agent to water is 1:110, and the mass ratio of the second cleaning agent to water is also 1:110.

[0046] Example 16: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of hydroxide to carbonate is 1:0.6.

[0047] Example 17: A membrane cleaning agent, which differs from Example 4 in that the mass ratio of hydroxide to carbonate is 1:0.8.

[0048] II. Comparative Example Comparative Example 1: The difference from Example 4 is that the first detergent is replaced with an equal amount of the second detergent, and water is added to the cleaning tank to a depth of 1m. 3 Add the prepared second detergent in an amount equal to that of the first detergent, with a mass ratio of the second detergent to water of 1:100. Heat to 45°C, open the valve to perform the first circulation cleaning of the reverse osmosis membrane, and the cleaning time is 6 hours. After the first cycle of cleaning is complete, fill the cleaning water tank to 1.8m. 3 Add the prepared second cleaning agent, heat to 45℃, and open the valve to perform a second cycle cleaning of the reverse osmosis membrane for 18 hours.

[0049] Comparative Example 2: The difference from Example 4 is that the mass ratio of the first detergent to the second detergent is 1:1.2.

[0050] Comparative Example 3: The difference from Example 4 is that the mass ratio of the first detergent to the second detergent is 1:2.2.

[0051] Comparative Example 4: The difference from Example 4 is that the processing enzyme in the detergent is replaced with an oxidant in equal amounts.

[0052] Comparative Example 5: The difference from Example 4 is that the oxidant in the detergent is replaced with an equal amount of processing enzyme.

[0053] Comparative Example 6: The difference from Example 4 is that 2,2-dibromo-3-nitropropamide in the bactericide is replaced with an equal amount of p-hydroxybenzoate.

[0054] Comparative Example 7: The difference from Example 4 is that the p-hydroxybenzoate in the bactericide is replaced with an equal amount of 2,2-dibromo-3-nitropropionic acid amide.

[0055] Comparative Example 8: The difference from Example 4 is that, in use, the first detergent and the second detergent are directly mixed, and then water with a mass ratio of 100 to the total mass of the first detergent and the second detergent is added. The mixture is heated to 45°C, and the valve is opened for circulation cleaning.

[0056] III. Performance Testing First, record the inlet water pressure, outlet water pressure, and product water flow rate of the reverse osmosis system for 5 consecutive days before cleaning, and take the average value. Then, the inlet water pressure, outlet water pressure, and permeate flow rate of the reverse osmosis systems after cleaning with the membrane cleaning agents and cleaning methods of Examples 1-15 and Comparative Examples 1-8 were recorded for 5 consecutive days, and the average value was taken. The test results are shown in Table 3.

[0057] Table 3: IV. Results Analysis and Summary Based on Examples 1-3 and Table 3, it can be seen that the content of each component in the first cleaning agent of Examples 1-3 is different. Table 3 shows that the inlet and outlet water pressure difference of the reverse osmosis system in the field operation of Examples 1-3 is significantly lower than that before cleaning, and the permeate water volume is significantly higher than that before cleaning. Furthermore, the inlet and outlet water pressure difference of Example 2 is lower than that of Example 1, and the permeate water volume is higher than that of Example 1, while the inlet and outlet water pressure difference and permeate water volume of Example 3 are comparable to those of Example 2.

[0058] As can be seen from the above, the first cleaning agent, which is composed of a cleaning agent, a penetrant, and a defoamer, can be used in combination with the second cleaning agent to effectively clean the reverse osmosis membrane, thereby reducing the situation where the reverse osmosis membrane is fouled and the water treatment efficiency decreases. Furthermore, the content of each component of the first cleaning agent in Example 2 can achieve a relatively optimal cleaning effect while saving reagent usage, thereby reducing cleaning costs.

[0059] Based on Examples 2, 4-5, and Table 3, it can be seen that the content of each component in the second detergent of Examples 4-5 differs from that of Example 2. Table 3 shows that the inlet and outlet water pressure difference in the reverse osmosis system of Example 4 is lower than that of Example 2, and the permeate water volume is higher than that of Example 2; the inlet and outlet water pressure difference in Example 5 is slightly higher than that of Example 2, and the permeate water volume is slightly lower than that of Example 2. Therefore, the content of each component in the second detergent of Example 4 can achieve a relatively optimal cleaning effect while saving reagent usage, thereby reducing cleaning costs.

[0060] Based on Examples 4, 6-7 and Table 3, it can be seen that the mass ratio of the first detergent and the second detergent in Examples 6-7 is different from that in Example 4. As can be seen from Table 3, the inlet and outlet water pressure difference of the reverse osmosis system in Example 6-7 is higher than that in Example 4, and the water production is lower than that in Example 4.

[0061] Furthermore, referring to Comparative Examples 1-3, it can be seen that in Comparative Example 1, the first detergent was replaced with an equal amount of the second detergent, meaning that the second detergent was used in both the first and second cycle cleaning. As shown in Table 3, the inlet and outlet water pressure difference in Comparative Example 1 was significantly higher than that in Examples 4 and 6-7, and the water production was significantly lower than that in Examples 4 and 6-7. Moreover, the mass ratio of the first detergent to the second detergent in Comparative Examples 2-3 was outside the scope of this application. As shown in Table 3, the inlet and outlet water pressure difference in Comparative Examples 2-3 was significantly higher than that in Examples 4 and 6-7, and the water production was significantly lower than that in Examples 4 and 6-7.

[0062] As can be seen from the above, when cleaning is performed using only the second detergent, the cleaning effect is significantly worse than when the first and second detergents are used together; and when the first and second detergents are used together in a mass ratio of 1:1.8, the cleaning effect is relatively better.

[0063] Based on Examples 4, 8-9 and Table 3, it can be seen that the mass ratio of the treatment enzyme and oxidant in the detergent in Examples 8-9 is different from that in Example 4. As can be seen from Table 3, the inlet and outlet water pressure difference of the reverse osmosis system in Examples 8-9 is higher than that in Example 4, and the water production is lower than that in Example 4.

[0064] Furthermore, based on Comparative Examples 4-5, it can be seen that in Comparative Example 4, the processing enzyme in the detergent was replaced with an oxidant in equal amounts, and in Comparative Example 5, the oxidant in the detergent was replaced with a processing enzyme in equal amounts. As can be seen from Table 3, the inlet and outlet water pressure difference of Comparative Examples 4-5 is significantly higher than that of Examples 4 and 8-9, and the water production is significantly lower than that of Examples 4 and 8-9.

[0065] As can be seen from the above, using a combination of oxidant and processing enzyme as a cleaning aid results in a better cleaning effect on the reverse osmosis membrane compared to using either oxidant or processing enzyme alone; and the cleaning effect on the reverse osmosis membrane is even better when the mass ratio of oxidant to processing enzyme in the cleaning aid is 1:0.5.

[0066] Based on Examples 4, 10-11, and Table 3, it can be seen that the mass ratios of protease, cellulase, hemicellulase, pectinase, and gelase in the treatment enzymes of Examples 10-11 are different from those in Example 4. Table 3 shows that the inlet and outlet water pressure difference in the reverse osmosis system of Examples 10-11 is higher than that of Example 4, and the permeate water production is lower than that of Example 4. Therefore, it can be concluded that a mass ratio of protease, cellulase, hemicellulase, pectinase, and gelase in the treatment enzymes of 1:0.4:0.15:0.3:0.7 results in a relatively better cleaning effect on the reverse osmosis membrane.

[0067] Based on Examples 4, 12-13 and Table 3, it can be seen that the mass ratios of p-hydroxybenzoate, 2,2-dibromo-3-nitropropamide and 3-propanediol in the bactericides of Examples 12-13 are different from those in Example 4. As can be seen from Table 3, the inlet and outlet water pressure difference of the reverse osmosis system in Examples 12-13 is higher than that in Example 4, and the water production is lower than that in Example 4.

[0068] Furthermore, comparing Comparative Examples 6 and 7, in Comparative Example 6, 2,2-dibromo-3-hydantoinamide in the bactericide was replaced with an equal amount of para-hydroxybenzoate, and in Comparative Example 7, para-hydroxybenzoate in the bactericide was replaced with an equal amount of 2,2-dibromo-3-hydantoinamide. As can be seen from Table 3, the inlet and outlet water pressure difference in Comparative Examples 6 and 7 was significantly higher than that in Examples 4 and 10-11, and the water production was significantly lower than that in Examples 4 and 10-11.

[0069] As can be seen from the above, using a combination of parabens and organic bromine as a bactericide results in a better cleaning effect on the reverse osmosis membrane compared to using parabens or organic bromine alone; furthermore, the cleaning effect on the reverse osmosis membrane is even better when the mass ratio of parabens, organic bromine and alcohol solvent in the bactericide is 1:0.5:3.

[0070] Based on Examples 4, 14-15, and Table 3, it can be seen that the masses of the first / second cleaning agent and water used in Examples 14-15 are different from those in Example 4. Table 3 shows that the inlet and outlet water pressure difference in the reverse osmosis system of Examples 14-15 is higher than that of Example 4, and the permeate water production is lower than that of Example 4. Therefore, it can be concluded that a mass ratio of 1:100 for both the first cleaning agent and water, and a mass ratio of 1:100 for the second cleaning agent and water, results in a better cleaning effect on the reverse osmosis membrane.

[0071] Based on Comparative Example 8 and Table 3, it can be seen that in Comparative Example 8, the first and second cleaning agents were directly mixed for cyclic cleaning. Table 3 shows that the inlet and outlet water pressure difference in Comparative Example 8 was significantly higher than in Example 4, and the permeate water production was significantly lower than in Example 4. Therefore, it can be concluded that the cleaning effect of first preparing the first cleaning agent into a cleaning solution for the first cyclic cleaning of the reverse osmosis membrane, and then preparing the second cleaning agent into a cleaning solution for the second cyclic cleaning, is significantly better than directly mixing the first and second cleaning agents.

[0072] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the products, methods and principles of this application should be covered within the scope of protection of this application.

Claims

1. A membrane cleaning agent, characterized in that: It includes a first detergent and a second detergent in a mass ratio of 1:(1.6-1.9); The first detergent comprises the following components and their contents: 20-24% detergent builder, 10-16% penetrant, 3-5% non-silicone defoamer, and the balance being water; The detergent additive comprises a treatment enzyme and an oxidant in a mass ratio of 1:(0.4-0.6); The second detergent comprises the following components and their contents: 1-5% inorganic alkaline detergent, 5-10% surfactant, and 10-12%... Bactericide, 10-12% dispersant, 3-5% non-silicone defoamer, balance water; The inorganic alkaline detergent comprises hydroxide and carbonate in a mass ratio of 1:(0.6-0.8); The processing enzymes include protease, cellulase, hemicellulase, pectinase, and gelling enzyme in a mass ratio of 1:(0.3-0.5):(0.1-0.2):(0.2-0.4):(0.6-0.8); The oxidant is selected from at least one of hydrogen peroxide, peracetic acid, and sodium dichromate; The penetrant is selected from at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether and sodium aminosulfonate; The surfactant is selected from at least one of ethylenediaminetetraacetic acid tetrasodium salt, sodium dodecylbenzenesulfonate, sodium alkyl polyoxyethylene ether sulfate, and sodium oleoylmethyl taurate. The bactericide comprises a paraben, an organic bromine, and an alcohol solvent in a mass ratio of 1:(0.4-0.6):(2-4); The dispersant includes at least one of a sulfonic acid-containing phosphonocarboxylic acid copolymer and hydrolyzed polymaleic anhydride; The non-silicone defoamer is selected from at least one of fatty acid glycerides, trialkyl, dialkyl phosphates and palmitic acid.

2. A method for preparing the membrane cleaning agent as described in claim 1, characterized in that, Includes the following steps: The detergent, penetrant, non-silicone defoamer and water in the above-mentioned amounts are mixed and stirred evenly to obtain the first detergent; Mix the inorganic alkaline detergent, surfactant, bactericide, dispersant, non-silicone defoamer, and water according to the above-mentioned amounts. Stir well to obtain the second detergent; The first detergent and the second detergent are separated and packaged to obtain a membrane cleaning agent, wherein the mass ratio of the first detergent to the second detergent is 1:(1.6-1.9).

3. A method of using a membrane cleaning agent prepared by the method described in claim 1 or the method described in claim 2, characterized in that, Includes the following steps: Add the first detergent to water, with a mass ratio of the first detergent to water of 1:(90-110), heat to 30-35℃, and open the valve to perform the first circulation cleaning; After the first cycle cleaning is completed, the second detergent is added to the water at a mass ratio of 1:(90-110). The water is heated to 40-50°C, and the valve is opened to perform the second cycle cleaning.

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