Multifunctional composite cleaning agent, preparation method and application of multifunctional composite cleaning agent in high-salinity wastewater flexible membrane treatment system

Abstract

The invention belongs to the technical field of cleaning agents, and particularly relates to a multifunctional composite cleaning agent, a preparation method and application of the multifunctional composite cleaning agent in a high-salinity wastewater flexible membrane treatment system. The invention provides a multifunctional composite cleaning agent which comprises the following raw materials in percentage by mass: 30-60% of a functional ampholytic surfactant, 5-15% of a high-molecular polymer, 5-10% of polyethylene glycol, 0.2-2.5% of a solubilizer, 0.1-1% of sodium dodecyl benzene sulfonate, 3-8% of a mixed enzyme agent and the balance of water, the high-molecular polymer is prepared from polyaspartate, polyacrylic acid and hydroxypropyl methyl cellulose. Through formula optimization, the multifunctional composite cleaning agent with excellent performance is obtained, and the multifunctional composite cleaning agent is mild and environmentally friendly, has relatively good cleaning efficiency on a reverse osmosis membrane, and can prolong the service life of the reverse osmosis membrane and reduce the operation cost.

Description

Technical Field

[0001] The invention belongs to the technical field of cleaning agents, and in particular relates to a multifunctional composite cleaning agent, a preparation method and application thereof in a high-salt wastewater flexible membrane treatment system. Background Art

[0002] Reverse osmosis membrane technology is widely used in the fields of seawater desalination, pure water preparation, industrial wastewater treatment, etc. However, during the operation of the reverse osmosis membrane, various substances in the raw water will gradually accumulate on the membrane surface, forming pollution. Common pollutants include inorganic substances, such as calcium carbonate, calcium sulfate, metal oxides, etc., which are mainly derived from minerals dissolved in water. Under specific conditions (such as pH value and temperature changes), they will crystallize and precipitate and deposit on the membrane surface. Organic pollution is also relatively common, such as natural organic matter (such as humic acid, fulvic acid), microbial metabolites, organic polymers in industrial wastewater, etc. These organic substances will attach to the membrane through adsorption, bridging, etc. In addition, microbial pollution is also relatively serious. Microorganisms such as bacteria, algae, and fungi grow and reproduce on the membrane surface to form biofilms, which not only block the membrane pores, but also trigger a series of biochemical reactions, further damaging the performance of the membrane. These pollutions will cause the flux of the reverse osmosis membrane to decrease and increase energy consumption. At the same time, pollution will also reduce the desalination rate of the membrane, resulting in poor water quality of the produced water, which cannot meet the requirements of production or domestic water. If long-term pollution accumulation is not handled in time, it will accelerate the aging and damage of the membrane, shorten the service life of the membrane, and increase the cost of membrane replacement. Therefore, an effective cleaning agent is needed to clean the contaminated reverse osmosis membrane to increase the service life of the membrane and save costs.

[0003] However, there are problems such as limited cleaning agent effect, damage to membrane materials and poor environmental friendliness in traditional cleaning agents. Patent CN 114621833 A discloses a liquid non-phosphorus alkaline membrane cleaning agent, including sodium hydroxide, tetrasodium iminodisuccinate, tetrasodium ethylenediaminetetraacetic acid, sodium metasilicate, sodium gluconate, sodium toluenesulfonate, surfactant and other components, and the surfactant is prepared by heating reaction of dodecylbenzenesulfonic acid and lysine. The obtained liquid non-phosphorus alkaline membrane cleaning agent has a stable and excellent cleaning effect, which can greatly extend the service life of reverse osmosis membranes, ultrafiltration membranes, etc. However, the sodium hydroxide in the cleaning agent raw material in the invention, as a strong alkaline component, helps to remove pollutants such as grease and protein, but is highly corrosive to membrane materials. For some sensitive reverse osmosis membranes, such as polyamide composite membranes, in a strong alkaline environment, the amide bond of the membrane is prone to hydrolysis reaction, resulting in damage to the membrane structure, reduced desalination rate, decreased flux, and shortened membrane service life. Even within a reasonable usage concentration and time range, long-term use of cleaning agents containing sodium hydroxide may gradually accumulate its corrosive effects on membrane materials, causing the performance of the membrane to gradually deteriorate and increasing the cost of membrane replacement.

[0004] In addition, in industrial production, industries such as chemical, pharmaceutical, petroleum, papermaking, dairy processing and food canning will produce high-salinity wastewater. High-salinity water bodies may contain a variety of pollutants such as organic matter, heavy metal ions, suspended solids, etc. The composition is relatively complex, which will affect the flux of the reverse osmosis membrane and there is a risk of salt crystallization and membrane pollution, making it difficult for traditional wastewater treatment processes to operate effectively and difficult to treat.

[0005] Therefore, it is of practical significance to develop a cleaning agent that is environmentally friendly, suitable for high-salinity water bodies, and less harmful to flexible reverse osmosis membranes. Summary of the invention

[0006] The invention discloses a multifunctional composite cleaning agent, a preparation method and application thereof in a flexible membrane treatment system for high-salt wastewater. By optimizing the formula, a multifunctional composite cleaning agent with excellent performance is obtained. The cleaning agent is mild and environmentally friendly, has good cleaning efficiency for a fouled reverse osmosis membrane, can extend the cleaning cycle and the service life of the reverse osmosis membrane, helps to reduce the project footprint, cuts down on operating costs, and brings a more efficient and economical solution to the sewage treatment industry.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a multifunctional composite cleaning agent, which comprises the following raw materials, calculated by 100% by mass: Functional amphoteric surfactant 30-60%, high molecular polymer 5-15%, polyethylene glycol 5-10%, solubilizer 0.2-2.5%, sodium dodecylbenzene sulfonate 0.1-1%, mixed enzyme 3-8%, and the balance is water; The high molecular polymer comprises polyaspartate, polyacrylic acid and hydroxypropyl methylcellulose.

[0008] In some embodiments, the preparation method of the functional amphoteric surfactant is: Dissolve sodium fatty alcohol polyoxyethylene ether sulfate in a solvent, add N-methylglucamine solution dropwise thereto under stirring, stir evenly, adjust the pH to 8-10, heat to 60-80°C, stir and react at 100-200rpm for 3-5h, cool to room temperature, add imidazoline surfactant and cocamidopropyl betaine to the reaction product, stir evenly, and obtain a functional amphoteric surfactant.

[0009] In some embodiments, the mass ratio of the sodium fatty alcohol polyoxyethylene ether sulfate to N-methyl glucamine is (1.5-2):1.

[0010] In some embodiments, the mass ratio of the reaction product, the imidazoline-type surfactant, and cocamidopropyl betaine is 6:(1-3):(1-2).

[0011] In some embodiments, the imidazoline-type surfactant comprises at least one of sulfonate imidazoline, imidazoline phosphate functional amphoteric surfactant, 2-lauryl-N-carboxymethyl-N-hydroxyethyl imidazoline, and 2-alkyl-N-hydroxyethyl-N-hydroxypropyl sulfoimidazoline.

[0012] In some embodiments, the enzyme mixture comprises protease, lipase, amylase and cellulase.

[0013] Preferably, the mass ratio of protease, lipase, amylase and cellulase in the mixed enzyme agent is (3-5):(2-3):(1-2):(1-1.5).

[0014] In some embodiments, the mass ratio of polyaspartate, polyacrylic acid, and hydroxypropyl methylcellulose is (1-3):(1-3):(2-4).

[0015] In some embodiments, the solubilizing agent is selected from at least one of isopropyl alcohol, polyoxyethylene nonionic surfactants, cyclodextrin and its derivatives, and urea.

[0016] In some embodiments, the polyethylene glycol is selected from at least one of polyethylene glycol 400, polyethylene glycol 600, polyethylene glycol 1000, and polyethylene glycol 2000.

[0017] The second aspect of the present invention provides a method for preparing the multifunctional composite cleaning agent described in the above scheme, comprising the following preparation steps: At a stirring speed of 200-300 rpm, polyaspartate is added to water and stirred until dissolved, and then polyacrylic acid and hydroxypropyl methylcellulose are added in sequence and stirred for 60-90 minutes until dissolved; then a solubilizer, polyethylene glycol, sodium dodecylbenzene sulfonate, and a functional amphoteric surfactant are added in sequence and stirred for 60-120 minutes, and finally a mixed enzyme is added and stirred for 30-60 minutes, and the remaining water is added to replenish the system to 100% by mass, and stirred to obtain the multifunctional composite cleaning agent.

[0018] The third aspect of the present invention provides an application of the multifunctional composite cleaning agent described in the above scheme in a high-salt wastewater flexible membrane treatment system.

[0019] The multifunctional composite cleaning agent of the present invention has a mild formula and a pH value between 7.5 and 9.5. Compared with single-function cleaning agents on the market, the multifunctional composite cleaning agent of the present invention has universal applicability and can be applied to various wastewater treatment fields, including high-salt industrial wastewater, zero wastewater discharge, material resource recovery, etc. It has excellent cleaning effects on pollutants such as COD, BOD, ammonia nitrogen, suspended solids, and inorganic scaling in wastewater that are very likely to cause blockage of reverse osmosis membranes, and can significantly increase the number of times and life of the membrane and reduce operating costs.

[0020] In order to obtain a reverse osmosis membrane cleaning agent with better performance, the present invention uses sodium fatty alcohol polyoxyethylene ether sulfate and N-methyl glucosamine as raw materials to make them react chemically. Under specific reaction conditions, the amino group of N-methyl glucosamine initiates a nucleophilic substitution reaction on some groups on the sulfate group of sodium fatty alcohol polyoxyethylene ether sulfate, modifies the structure of sodium fatty alcohol polyoxyethylene ether sulfate, and obtains a new surfactant (reaction product). The functional amphoteric surfactant is mixed with an imidazoline surfactant and cocamidopropyl betaine to obtain a functional amphoteric surfactant with excellent performance. The reaction product itself has a certain surface activity and can remove some pollutants. The imidazoline surfactant has good emulsification and dispersing ability for grease and organic matter. Cocamidopropyl betaine can produce rich foam to carry dirt. The combination of the three can make the cleaning agent have better removal effect on different types of pollutants, such as grease, protein, polysaccharide, etc., and expand the scope of decontamination.

[0021] The functional amphoteric surfactant in the multifunctional composite cleaning agent of the present invention has good surface activity, can reduce the surface tension of water, and through emulsification and dispersion, wraps organic matter that is easy to cause membrane clogging to form micelles, so that the micelles are dispersed in water; the functional amphoteric surfactant is adsorbed on the surface of pollutants, so that the surface of pollutants has a certain charge; polyacrylic acid can make organic pollutants more stably dispersed in water through electrostatic repulsion and steric hindrance, and it is not easy to re-aggregate on the membrane surface; the functional amphoteric surfactant can also improve the solubility and dispersibility of hydroxypropyl methylcellulose in water, and improve the adhesion and durability of the cleaning agent on the membrane surface ... Diol can penetrate into the micropores of the membrane, reduce the adhesion between organic matter and the membrane surface, and facilitate the cleaning of organic matter; sodium dodecylbenzene sulfonate can separate organic matter from the membrane surface through electrostatic and hydrophobic effects, and play a role in decontamination; and high molecular polymers can play the role of dispersion and chelation, thickening and suspension, corrosion inhibition and protection, and indirectly protect the membrane system by improving the performance of the cleaning solution and stabilizing the cleaning solution system. The polyaspartate and polyacrylic acid have targeted effects on metal ions and scale pollutants, and can form stable chelates with metal ions such as calcium, magnesium, and iron in sewage to prevent these metal ions from depositing on the membrane surface to form a scale layer. The various enzymes in the mixed enzyme agent have excellent degradation effects on protein pollutants, starch pollutants, and cellulose substances, and can effectively remove these pollutants and keep the membrane clean and permeable. In addition, functional amphoteric surfactants and sodium dodecylbenzene sulfonate have certain inhibitory and removal effects on microorganisms. Combined with the various enzymes in the mixed enzyme agent, it can effectively clean the microbial fouling as a whole.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention focuses on the in-depth optimization of the formula and successfully develops a multifunctional composite cleaning agent with excellent performance. The cleaning agent has significant mild and environmentally friendly characteristics, and exhibits extremely high cleaning efficiency for reverse osmosis membranes. It can not only effectively remove various stubborn dirt, but also reduce damage to membrane materials, thereby significantly extending the service life of reverse osmosis membranes. The use of the cleaning agent of the present invention can greatly simplify the wastewater treatment process and streamline the originally cumbersome and complicated treatment steps. At the same time, it can cope with more difficult water quality challenges and effectively treat various complex sewage. This feature not only helps to reduce the project footprint, but also significantly cuts operating costs, bringing more efficient and economical solutions to the sewage treatment industry.

[0024] 2. The present invention uses sodium fatty alcohol polyoxyethylene ether sulfate and N-methylglucosamine as raw materials to react chemically to form new chemical bonds, thereby obtaining a new surfactant. The surfactant is compounded with an imidazoline surfactant and cocamidopropyl betaine, so that the cleaning agent can have a better removal effect on different types of pollutants, such as grease, protein, polysaccharide, etc. Compared with the cleaning agents with a single function on the market, the composite cleaning agent of the present invention has mild ingredients, a wider cleaning effect, and stronger universality.

[0025] 3. The multifunctional composite cleaning agent of the present invention also adds a high molecular polymer composed of polyaspartate, polyacrylic acid and hydroxypropyl methylcellulose in a specific proportion, which can play the role of dispersion and chelation, thickening and suspension, corrosion inhibition and protection, and indirectly protect the composite membrane by improving the performance of the cleaning liquid and stabilizing the system of the cleaning liquid. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. Various modifications and variations may be made to the specific embodiments of the present invention specification without departing from the scope or spirit of the present invention, which will be apparent to those skilled in the art. Other embodiments obtained from the present invention specification will be apparent to the technician. The present application specification and examples are exemplary only.

[0029] The words “include,” “including,” “have,” or “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0030] The sodium fatty alcohol polyoxyethylene ether sulfate used in the present invention is AES-70, the cocamidopropyl betaine used is CAB-40; the sodium polyaspartate used is PASP-5000, and the polyacrylic acid used is PAAS-6000; the Mn of the hydroxypropyl methylcellulose used is 10000; the fatty alcohol polyoxyethylene ether used is AEO-9; the enzyme activities of the protease, lipase, amylase and cellulase used are all 100000 U / g; and the cyclodextrin used is β-cyclodextrin.

[0031] Example 1 A method for preparing a multifunctional composite cleaning agent comprises the following preparation steps: At a stirring speed of 200 rpm, 1.25 g of sodium polyaspartate was added to 20 mL of water and stirred until dissolved. Then, 1.25 g of polyacrylic acid and 2.5 g of hydroxypropyl methylcellulose were added in sequence and stirred for 60 min until dissolved. Then, 0.2 g of isopropanol, 10 g of polyethylene glycol 400, 0.1 g of sodium dodecylbenzene sulfonate and 60 g of functional amphoteric surfactant were added in sequence and stirred for 60 min. Finally, 3 g of mixed enzyme was added and stirred for 30 min. The remaining water was added to supplement the system to a mass of 100 g and stirred evenly to obtain the multifunctional composite cleaning agent.

[0032] The preparation method of the functional amphoteric surfactant used is as follows: 150g of sodium fatty alcohol polyoxyethylene ether sulfate is dissolved in 500mL of deionized water, 250mL of an aqueous solution containing 100g of N-methylglucamine is added dropwise thereto at a stirring speed of 100rpm, the mixture is stirred evenly, the pH is adjusted to 8, the temperature is raised to 60°C, the mixture is stirred at 100rpm for reaction for 5h, and the mixture is cooled to room temperature to obtain a reaction product; 10g of 1,3-dimethylimidazoline methane sulfonate and 10g of cocamidopropyl betaine are added to 60g of the reaction product, the mixture is stirred evenly, and the functional amphoteric surfactant is obtained.

[0033] The mixed enzyme used comprises protease, lipase, amylase and cellulase in a mass ratio of 3:2:1:1.

[0034] Example 2 A method for preparing a multifunctional composite cleaning agent comprises the following preparation steps: At a stirring speed of 300 rpm, 4.5 g of sodium polyaspartate was added to 30 mL of water and stirred until dissolved. Then, 4.5 g of polyacrylic acid and 6 g of hydroxypropyl methylcellulose were added in sequence and stirred for 90 min until dissolved. Then, 2.5 g of fatty alcohol polyoxyethylene ether, 5 g of polyethylene glycol 1000, 1 g of sodium dodecylbenzene sulfonate and 30 g of functional amphoteric surfactant were added in sequence and stirred for 120 min. Finally, 8 g of mixed enzyme was added and stirred for 60 min. The remaining water was added to supplement the system to a mass of 100 g and stirred evenly to obtain the multifunctional composite cleaning agent.

[0035] The preparation method of the functional amphoteric surfactant used is as follows: 200g of sodium fatty alcohol polyoxyethylene ether sulfate is dissolved in 500mL of deionized water, 250mL of an aqueous solution containing 100g of N-methylglucamine is added dropwise thereto at a stirring speed of 200rpm, the mixture is stirred evenly, the pH value is adjusted to 10, the mixture is heated to 80°C, stirred at 200rpm for reaction for 3h, and cooled to room temperature to obtain a reaction product; 30g of 2-lauryl-N-carboxymethyl-N-hydroxyethyl imidazoline and 20g of cocamidopropyl betaine are added to 60g of the reaction product, the mixture is stirred evenly to obtain a functional amphoteric surfactant.

[0036] The mixed enzyme used contained protease, lipase, amylase and cellulase in a mass ratio of 5:3:2:1.5.

[0037] Example 3 A method for preparing a multifunctional composite cleaning agent comprises the following preparation steps: At a stirring speed of 250 rpm, 3 g of sodium polyaspartate was added to 20 mL of water and stirred until dissolved. Then, 3 g of polyacrylic acid and 4 g of hydroxypropyl methylcellulose were added in sequence and stirred for 75 min until dissolved. Then, 2 g of cyclodextrin, 7.5 g of polyethylene glycol 600, 0.5 g of sodium dodecylbenzene sulfonate and 45 g of functional amphoteric surfactant were added in sequence and stirred for 100 min. Finally, 5 g of mixed enzyme was added and stirred for 45 min. The remaining water was added to supplement the system to a mass of 100 g and stirred evenly to obtain the multifunctional composite cleaning agent.

[0038] The preparation method of the functional amphoteric surfactant used is as follows: 180g of sodium fatty alcohol polyoxyethylene ether sulfate is dissolved in 500mL of deionized water, 250mL of an aqueous solution containing 100g of N-methylglucamine is added dropwise thereto at a stirring speed of 150rpm, the mixture is stirred evenly, the pH is adjusted to 9, the mixture is heated to 70°C, stirred at 150rpm for 4h, and cooled to room temperature to obtain a reaction product; 20g of 2-alkyl-N-hydroxyethyl-N-hydroxypropyl sulfoimidazoline and 15g of cocamidopropyl betaine are added to 60g of the reaction product, the mixture is stirred evenly to obtain a functional amphoteric surfactant.

[0039] The mixed enzyme used contained protease, lipase, amylase and cellulase in a mass ratio of 4:2.5:1.5:1.25.

[0040] Example 4 A method for preparing a multifunctional composite cleaning agent, the specific implementation method is roughly the same as that of Example 3, except that 120 g of fatty alcohol polyoxyethylene ether sodium sulfate is used in the preparation process of the functional amphoteric surfactant.

[0041] Example 5 A method for preparing a multifunctional composite cleaning agent, the specific implementation method is roughly the same as that of Example 3, except that 2-alkyl-N-hydroxyethyl-N-hydroxypropyl sulfoimidazoline is not added during the preparation of the functional amphoteric surfactant used.

[0042] Example 6 A method for preparing a multifunctional composite cleaning agent, the specific implementation method is substantially the same as that of Example 3, except that no cocamidopropyl betaine is added during the preparation of the functional amphoteric surfactant used.

[0043] Example 7 A method for preparing a multifunctional composite cleaning agent, the specific implementation method is roughly the same as that of Example 3, except that the preparation method of the functional amphoteric surfactant used is as follows: 120g of fatty alcohol polyoxyethylene ether sodium sulfate is dissolved in 500mL of deionized water, and 250mL of an aqueous solution containing 100g of N-methylglucamine is added dropwise thereto at a stirring speed of 150rpm, the mixture is stirred evenly, the pH is adjusted to 9, the temperature is raised to 70°C, the reaction is stirred for 4h, and the mixture is cooled to room temperature to obtain a functional amphoteric surfactant.

[0044] Example 8 A method for preparing a multifunctional composite cleaning agent, the specific implementation method is substantially the same as that of Example 3, except that an equal mass of the reaction product in Example 3 is used to replace the functional amphoteric surfactant.

[0045] Example 9 A method for preparing a multifunctional composite cleaning agent, the specific implementation method is roughly the same as that of Example 3, except that 2-alkyl-N-hydroxyethyl-N-hydroxypropyl sulfoimidazoline, cocamidopropyl betaine and the like in a mass ratio of 4:3 are used to replace the functional amphoteric surfactant of Example 3.

[0046] Example 10 A method for preparing a multifunctional composite cleaning agent comprises the following preparation steps: At a stirring speed of 250 rpm, 2 g of cyclodextrin, 7.5 g of polyethylene glycol 600, 0.5 g of sodium dodecylbenzene sulfonate, and 45 g of a functional amphoteric surfactant were added to 20 mL of water in sequence, and stirring was continued for 100 min. Finally, 5 g of the mixed enzyme agent was added and stirred for 45 min. The remaining water was added to supplement the system to a mass of 100 g, and stirred evenly to obtain the multifunctional composite cleaning agent.

[0047] The functional amphoteric surfactant used is the functional amphoteric surfactant prepared in Example 3.

[0048] The mixed enzyme used contained protease, lipase, amylase and cellulase in a mass ratio of 4:2.5:1.5:1.25.

[0049] Comparative Example 1 A method for preparing a multifunctional composite cleaning agent, the specific implementation method is substantially the same as that of Example 3, except that no mixed enzyme agent is added.

[0050] The comprehensive effects and performances of the multifunctional composite cleaning agents prepared in the above-mentioned embodiments and comparative examples are reflected in the following performance test contents.

[0051] Performance Testing Experiment 1

[0052] 1. Foam performance test: The multifunctional composite cleaning agent obtained in each embodiment and comparative example was prepared into a cleaning solution with a concentration of 0.2wt% with water. At an experimental temperature of 40°C, 400mL of the solution was flowed to the same liquid surface at a height of 450mm. The foam height was read after 5 minutes, and the height was ≤20mm.

[0053] 2. Stability performance test: The multifunctional composite cleaning agent obtained in each embodiment and comparative example was placed in a low temperature environment (-10°C) for 24 hours and a high temperature environment (60°C) for 10 hours, and then placed at room temperature to check whether it is uniform and whether there is stratification, crystallization or precipitation.

[0054] 3. Cleaning performance test: The multifunctional composite cleaning agent of each embodiment above is used to clean the reverse osmosis membrane of a chemical plant: first rinse the membrane machine with clean water, and prepare the multifunctional composite cleaning agent of each embodiment of the present invention and the comparative example with deionized water into a 5wt% cleaning solution, the cleaning solution enters the membrane for circulation for 45 minutes, the cleaning solution soaks the membrane for 60 minutes, and the cleaning solution enters the membrane for circulation for 45 minutes again, the cleaning solution is emptied, and the membrane system is rinsed with clean water until the pH of the rinse water is 7, and the cleaning is completed. The cleaning temperature is 35°C and the cleaning pressure is 0.2MPa. The membrane flux and desalination rate before and after cleaning are tested using a membrane machine to determine the use effect of the multifunctional composite cleaning agent. The detection method is carried out in accordance with GB T32373-2015.

[0055] The specific test results are shown in Table 1.

[0056] Table 1

[0057] As shown in Table 1, the cleaning agents prepared in Examples 1-3 have good comprehensive performance, good stability, low foam height, are not easy to generate a large number of bubbles, are conducive to equipment operation, and have excellent cleaning effects on reverse osmosis membranes. Compared with Example 3, the preparation method of the functional amphoteric surfactant used in Examples 4-7 has changed, and the composition has changed, which in turn affects the solubilization and decontamination effect of the composite cleaning agent on the pollutants on the membrane surface, resulting in a different degree of reduction in the cleaning effect on the reverse osmosis membrane; the composition of the cleaning agents obtained by each embodiment and comparative example used in Examples 8 and 9 has changed, which will also affect the solubilization and decontamination effect of the composite cleaning agent on the pollutants on the membrane surface; no high molecular weight polymer is added in Example 10, and no mixed enzyme agent is added in Comparative Example 1, which will cause the cleaning performance of the composite cleaning agent to decrease.

[0058] Application Example 1 A chemical plant uses reverse osmosis equipment to treat ammonium sulfate wastewater. During operation, the equipment frequently blocks the water. The water flow rate at the initial stage of commissioning is 6.0m 3 / h, the pressure difference is 1.5bar. After two weeks of continuous operation, the water flow rate dropped to 3.5m 3 / h, the pressure difference rises to 3.2bar. After cleaning with conventional cleaning agents on the market, the water flow rate can only be restored to 5.0m 3 / h, the pressure difference recovered to about 2.8bar, and the flux pressure difference returned to the state before cleaning in less than three days of operation. The multifunctional composite cleaning agent prepared in Example 3 of the present invention was prepared into a cleaning agent at 5wt% to clean the membrane. The specific operation is shown in Experiment 1. The membrane after cleaning was analyzed, and the specific data is shown in Table 2.

[0059] Table 2

[0060] It can be seen from Table 2 that the multifunctional composite cleaning agent prepared in Example 3 has an excellent cleaning effect on the fouled reverse osmosis membrane, can extend the cleaning cycle, and save a lot of costs.

[0061] Application Example 2 The wastewater produced by a certain breeding farm has a large number of microbial breeding problems, and the conventional cleaning agents used are not effective. The multifunctional composite cleaning agent prepared in Example 3 of the present invention is prepared into a cleaning agent at 5wt% for cleaning. The specific operation is shown in Experiment 1. The cleaned membrane is analyzed. Before cleaning, a sterile cotton swab is used to scrape the membrane at 5 locations, put it into a sterile dilution bottle and dilute it with an agar aqueous solution to obtain a diluent, and then the diluent is evenly applied on a culture dish, and taken out after culturing at a constant temperature of 30°C for 3 days, and the number of colonies on the culture dish is observed and recorded; after cleaning, a sterile cotton swab is used to scrape the same 5 locations of the membrane, and the culturing steps are the same as described above. The number of colonies on the culture dish is observed and recorded to determine the microbial removal rate (%). Specific data are shown in Table 3.

[0062] Table 3

[0063] It can be seen from Table 3 that the multifunctional composite cleaning agent prepared in Example 3 has an excellent cleaning effect on the fouled reverse osmosis membrane. The contact angle of the membrane surface before and after cleaning is reduced from about 85° after contamination to about 25°, which greatly improves the hydrophilicity of the membrane surface, thereby improving the sewage treatment effect; while extending the cleaning cycle, it also has a good cleaning rate for the microorganisms on the membrane.

[0064] Application Example 3 The wastewater from a certain evaporation pond has a water quality as shown in Table 4. It has high hardness and high calcium and magnesium content, and is easy to form calcium carbonate and calcium sulfate scale to block the membrane pores. The reverse osmosis operation is shown in Table 5, and the reverse osmosis membrane used is the company's AMBC membrane. As can be seen from Table 5, after one week of operation, the reverse osmosis membrane element is blocked, the water inlet pressure increases, the actual water production flow rate decreases significantly, and the recovery rate decreases. Although it can be roughly restored to the designed flow rate after cleaning with conventional acid and alkali cleaning agents, the water volume still decays to 80.5% of the designed water production flow rate after 2 days of operation. Elemental analysis of the blocked reverse osmosis membrane found that the main components of the blockage of the reverse osmosis membrane were calcium carbonate and calcium sulfate inorganic salts. The blocked reverse osmosis membrane was cleaned using the multifunctional composite cleaning agent prepared in Example 3 of the present invention. The specific operation is shown in Experiment 1, and the various parameters of the membrane after cleaning are tested, see Table 6.

[0065] Table 4

[0066] Table 5

[0067] Table 6

[0068] As shown in Table 6, after the fouled membrane was cleaned with the multifunctional composite cleaning agent of the present invention, the actual water production flow of the membrane system was restored to 96.7% of the designed water production flow, the recovery rate was restored to 98.3% of the designed data, and the desalination rate was restored to 99.5% of the designed data, ensuring the normal operation of the system. Although the performance of the membrane system was reduced after one week of operation, it was still greatly improved compared with the membrane system that was not cleaned with the cleaning agent of the present invention, and the fouling situation was significantly alleviated.

[0069] In summary, the multifunctional composite cleaning agent of the present invention can treat wastewater with higher difficulty, effectively remove various stubborn dirt on the membrane, greatly simplify the wastewater treatment process, streamline the originally cumbersome and complicated treatment steps, extend the service life of the membrane system, and significantly reduce operating costs.

[0070] The above is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present application. Although the present application is disclosed as above in the preferred embodiment, it is not intended to limit the present application. Any technician familiar with the profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution.

Claims

1. A multifunctional composite cleaning agent, characterized in that: Based on 100% quality, it includes the following raw materials: Functional amphoteric surfactant 30-60%, high molecular polymer 5-15%, polyethylene glycol 5-10%, solubilizer 0.2-2.5%, sodium dodecylbenzene sulfonate 0.1-1%, mixed enzyme 3-8%, and the balance is water; The high molecular polymer comprises polyaspartate, polyacrylic acid and hydroxypropyl methylcellulose.

2. The multifunctional composite cleaning agent according to claim 1, characterized in that: The preparation method of the functional amphoteric surfactant is: Dissolve sodium fatty alcohol polyoxyethylene ether sulfate in a solvent, add N-methylglucamine solution dropwise thereto under stirring, stir evenly, adjust the pH to 8-10, heat to 60-80°C, stir and react at 100-200rpm for 3-5h, cool, add imidazoline surfactant and cocamidopropyl betaine to the reaction product, stir evenly, and obtain a functional amphoteric surfactant.

3. The multifunctional composite cleaning agent according to claim 2, characterized in that: The mass ratio of the fatty alcohol polyoxyethylene ether sodium sulfate to N-methylglucamine is (1.5-2):

1.

4. The multifunctional composite cleaning agent according to claim 2, characterized in that: The mass ratio of the reaction product, the imidazoline surfactant and cocamidopropyl betaine is 6:(1-3):(1-2).

5. The multifunctional composite cleaning agent according to claim 2, characterized in that: The imidazoline surfactant comprises at least one of sulfonate imidazoline, imidazoline phosphate functional amphoteric surfactant, 2-lauryl-N-carboxymethyl-N-hydroxyethyl imidazoline and 2-alkyl-N-hydroxyethyl-N-hydroxypropyl sulfoimidazoline.

6. The multifunctional composite cleaning agent according to claim 1, characterized in that: The mixed enzyme comprises protease, lipase, amylase and cellulase.

7. The multifunctional composite cleaning agent according to claim 1, characterized in that: The mass ratio of the polyaspartate, polyacrylic acid and hydroxypropyl methylcellulose is (1-3):(1-3):(2-4).

8. The multifunctional composite cleaning agent according to claim 1, characterized in that: The solubilizing agent is selected from at least one of isopropyl alcohol, polyoxyethylene nonionic surfactant, cyclodextrin and its derivatives, and urea.

9. A method for preparing the multifunctional composite cleaning agent according to any one of claims 1 to 8, characterized in that: The method comprises the following preparation steps: At a stirring speed of 200-300 rpm, polyaspartate is added into water and stirred until dissolved, and then polyacrylic acid and hydroxypropyl methylcellulose are added in sequence and stirred for 60-90 minutes until dissolved; then a solubilizer, polyethylene glycol, sodium dodecylbenzene sulfonate and a functional amphoteric surfactant are added in sequence and stirred for 60-120 minutes, and finally a mixed enzyme is added and stirred for 30-60 minutes, and the remaining water is added to replenish the system to 100% by mass, and stirred evenly to obtain the multifunctional composite cleaning agent.

10. Use of the multifunctional composite cleaning agent according to any one of claims 1 to 8 or the multifunctional composite cleaning agent prepared by the preparation method according to claim 9 in a high-salinity wastewater flexible membrane treatment system, characterized in that: The multifunctional composite cleaning agent is applied to the fields of cleaning membrane systems for high-salt industrial wastewater, zero wastewater discharge, and material resource recovery.

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