Composite corrosion inhibition type alkaline cleaning agent as well as preparation method and application thereof

Abstract

The invention relates to the technical field of cleaning agents, and particularly discloses a composite corrosion inhibition type alkaline cleaning agent and a preparation method and application thereof. The composite corrosion inhibition type alkaline cleaning agent provided by the invention is prepared from the following components in parts by weight: 10 to 25 parts of organic alkali, 5 to 15 parts of organic corrosion inhibitor, 5 to 8 parts of nonionic surfactant, 8 to 12 parts of chelating agent, 2 to 3 parts of biological enzyme compound, 3 to 5 parts of nano aluminum oxide and 50 to 75 parts of water, the organic slow-release agent is a mixture of sodium polyepoxysuccinate and a benzotriazole derivative in a weight ratio of 1: (2.5-3.5); the invention further provides a preparation method of the composite corrosion inhibition type alkaline cleaning agent and application of the composite corrosion inhibition type alkaline cleaning agent in reverse osmosis membrane element cleaning. The composite corrosion inhibition type alkaline cleaning agent provided by the invention can be used for comprehensively and efficiently cleaning pollutants deposited on the surface of a reverse osmosis membrane and recovering or maintaining normal water flux and desalting performance of the reverse osmosis membrane without causing membrane damage.

Description

Technical Field

[0001] The present application relates to the technical field of cleaning agents, and in particular to a composite corrosion-inhibiting alkaline cleaning agent and a preparation method and application thereof. Background Art

[0002] As a core component of water treatment, reverse osmosis (RO) membranes play a crucial role in the entire water treatment industry. With industrial development and increasing demand for water quality, RO membranes, thanks to their efficient separation performance, have been widely used in numerous fields, including seawater desalination, brackish water purification, industrial wastewater treatment, and drinking water production. These membranes significantly improve water resource utilization efficiency and meet the stringent water quality requirements of various industries. However, over long-term operation, RO membranes inevitably become contaminated by various types of contamination, which not only affects their normal performance but also shortens their service life, increasing the cost and difficulty of water treatment. Therefore, how to effectively clean RO membranes and restore their performance has become a key issue that needs to be addressed in the water treatment industry.

[0003] Currently, chemical cleaning is widely used in the industry to restore reverse osmosis membrane performance to address membrane fouling issues. Sodium hydroxide-based cleaning agents are a common alkaline cleaning agent used in chemical cleaning. These agents create a strong alkaline environment, destroying the structure of organic matter and microorganisms, thereby removing them from the membrane surface. However, in actual application, the above-mentioned cleaning agents still have many problems. For example: First, when acid-insoluble pollutants such as silicates and sulfates are present in the pollutants, the above-mentioned cleaning agents have insufficient removal ability and are difficult to meet the cleaning needs; second, when encountering complex pollution types such as oil-microorganism-inorganic scale, a single alkaline cleaning agent is difficult to remove all kinds of pollutants at the same time, and it is necessary to frequently switch between acidic and alkaline cleaning agents for multiple cleanings. The operation process is quite cumbersome and requires a lot of manpower and time; third, the high alkaline environment (pH>12) of sodium hydroxide-based cleaning agents can easily lead to membrane pore expansion or even perforation, resulting in irreversible increase in conductivity, seriously damaging the performance of the membrane and shortening the service life of the membrane; fourth, the existing cleaning agents also contain components such as phosphorus, which can easily cause eutrophication of the water body when discharged into the water body after cleaning, have a negative impact on the environment, and are not environmentally friendly.

[0004] Therefore, the development of a composite corrosion-inhibiting alkaline cleaning agent that can comprehensively and efficiently clean various pollutants deposited on the surface of the reverse osmosis membrane without causing membrane damage is of great significance to the water treatment industry. Summary of the Invention

[0005] In order to overcome the problems of insufficient cleaning ability and easy membrane damage in existing alkaline cleaning agents, the present application provides a composite corrosion-inhibiting alkaline cleaning agent and its preparation method and application.

[0006] In the first aspect, the present application provides a composite corrosion-inhibiting alkaline cleaning agent, which adopts the following technical solution: A composite corrosion-inhibiting alkaline cleaning agent comprises the following components in parts by weight: 10-25 parts of an organic base, 5-15 parts of an organic corrosion inhibitor, 5-8 parts of a nonionic surfactant, 8-12 parts of a chelating agent, 2-3 parts of a biological enzyme complex, 3-5 parts of nano-alumina, and 50-75 parts of water; The organic sustained-release agent is a mixture of sodium polyepoxysuccinate and a benzotriazole derivative in a weight ratio of 1:(2.5-3.5).

[0007] The present application provides a composite corrosion-inhibiting alkaline cleaning agent, which can achieve the simultaneous removal of various types of pollutants such as oil stains, biofilms and inorganic scales through the synergistic effect between the various components. Specifically: the organic alkali system (pH10.5-11.5) of the present application is slightly weaker in alkalinity than the traditional sodium hydroxide system (pH>12), so the risk of oxidative damage to the reverse osmosis membrane is lower; the synergistic effect of organic corrosion inhibitors, non-ionic surfactants, chelating agents and bio-enzyme complexes can achieve the simultaneous dissolution or removal of oil stains, biofilms and inorganic scales; nano-alumina can remove stubborn dirt on the membrane surface through physical action, enhance the wettability of the membrane surface, reduce the roughness of the membrane surface, and thus reduce the attachment of subsequent pollutants; in addition, the above-mentioned composite corrosion-inhibiting alkaline cleaning agent is a phosphorus-free formula and will not have a negative impact on the environment after use. In summary, the composite corrosion-inhibiting alkaline cleaning agent provided by the present application can not only improve the removal rate of various pollutants, but also effectively reduce the risk of oxidative damage to the reverse osmosis membrane, greatly extend the service life of the membrane, and has a good application prospect.

[0008] In some embodiments, the weight parts of the organic base can be 10-15 parts, 10-20 parts, 10-23 parts, 15-20 parts, 15-23 parts, 15-25 parts, 20-23 parts, 20-25 parts or 23-25 ​​parts.

[0009] In a specific embodiment, the weight parts of the organic base can be 10 parts, 15 parts, 20 parts, 23 parts or 25 servings.

[0010] In some embodiments, the weight portion of the organic corrosion inhibitor may be 5-8 parts, 5-10 parts, 5-13 parts, 8-10 parts, 8-13 parts, 8-15 parts, 10-13 parts, 10-15 parts or 13-15 parts.

[0011] In a specific embodiment, the weight portion of the organic corrosion inhibitor can be 5 parts, 8 parts, 10 parts, 13 parts or 15 parts.

[0012] In some embodiments, the weight ratio of the sodium polyepoxysuccinate to the benzotriazole derivative may be 1:(2.5-3) or 1:(3-3.5).

[0013] In a specific embodiment, the weight ratio of the sodium polyepoxysuccinate to the benzotriazole derivative is 1:2.5, 1:3 or 1:3.5.

[0014] Optionally, the composite corrosion-inhibiting alkaline cleaning agent comprises the following components in parts by weight: 15-23 parts of organic base, 8-13 parts of organic corrosion inhibitor, 5-8 parts of nonionic surfactant, 8-12 parts of chelating agent, 2-3 parts of biological enzyme complex, 3-5 parts of nano-alumina and 50-75 parts of water.

[0015] Optionally, the organic base is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, picoline, lutidine, collidine, ethanolamine and diethanolamine.

[0016] Optionally, the organic base is a mixture of tetramethylammonium hydroxide, lutidine and ethanolamine.

[0017] Optionally, the weight ratio of tetramethylammonium hydroxide, lutidine and ethanolamine is 1:(0.4-0.6):(0.1-0.2).

[0018] In some embodiments, the weight ratio of tetramethylammonium hydroxide, lutidine, and ethanolamine can be 1:(0.4-0.5):0.15, 1:(0.5-0.6):0.15, 1:0.5:(0.1-0.15), or 1:0.5:(0.15-0.2).

[0019] In a specific embodiment, the weight ratio of tetramethylammonium hydroxide, lutidine and ethanolamine can also be 1:0.4:0.15, 1:0.5:0.15, 1:0.6:0.15, 1:0.5:0.1 or 1:0.5:0.2.

[0020] Optionally, the nonionic surfactant is dodecyl glycoside.

[0021] Optionally, the chelating agent is HEDP.

[0022] Optionally, the biological enzyme complex is protease and lipase.

[0023] In a second aspect, the present application provides a method for preparing a composite corrosion-inhibiting alkaline cleaning agent.

[0024] A preparation method of a composite corrosion-inhibiting alkaline cleaning agent comprises the following steps: firstly, mixing an organic base with water and stirring evenly at ≤40°C; then, adding a nonionic surfactant and a chelating agent and stirring for 30-40 minutes; then, adding the remaining components and ultrasonically dispersing for 20-30 minutes to obtain the composite corrosion-inhibiting alkaline cleaning agent.

[0025] In a third aspect, the present application provides an application of a composite corrosion-inhibiting alkaline cleaning agent in cleaning reverse osmosis membrane elements.

[0026] In summary, this application has the following beneficial effects: 1. This application uses a mixture of sodium polyepoxysuccinate and benzotriazole derivatives in a weight ratio of 1: (2.5-3.5) as an organic sustained-release agent and an organic base as the main base. The prepared composite corrosion-inhibiting alkaline cleaning agent can comprehensively and efficiently clean the pollutants deposited on the surface of the reverse osmosis membrane, restore or maintain the normal water flux and desalination performance of the reverse osmosis membrane, and will not cause membrane damage.

[0027] 2. This application further controls the addition amount of organic base to 15-23 parts and the addition amount of organic slow-release agent to 8-13 parts, and the obtained composite corrosion-inhibiting alkaline cleaning agent has a better cleaning effect on pollutants on the surface of reverse osmosis membranes.

[0028] 3. This application further uses tetramethylammonium hydroxide, dimethylpyridine and ethanolamine in a weight ratio of 1: (0.4-0.6): (0.1-0.2) as organic bases. The prepared composite corrosion-inhibiting alkaline cleaning agent has a better cleaning effect on pollutants on the surface of the reverse osmosis membrane, can more thoroughly restore the normal water flux and desalination performance of the reverse osmosis membrane, and will not cause membrane damage. DETAILED DESCRIPTION

[0029] The present application provides a composite corrosion-inhibiting alkaline cleaning agent, comprising the following components in parts by weight: 10-25 parts of an organic base, 5-15 parts of an organic corrosion inhibitor, 5-8 parts of a nonionic surfactant, 8-12 parts of a chelating agent, 2-3 parts of a biological enzyme complex, 3-5 parts of nano-alumina, and 50-75 parts of water; further, the composite corrosion-inhibiting alkaline cleaning agent comprises the following components in parts by weight: 15-23 parts of an organic base, 8-13 parts of an organic corrosion inhibitor, 5-8 parts of a nonionic surfactant, 8-12 parts of a chelating agent, 2-3 parts of a biological enzyme complex, 3-5 parts of nano-alumina, and 50-75 parts of water.

[0030] The organic slow-release agent is a mixture of sodium polyepoxysuccinate and a benzotriazole derivative in a weight ratio of 1:(2.5-3.5). The composite corrosion-inhibiting alkaline cleaning agent comprises the following components in parts by weight: 15-23 parts of an organic base, 8-13 parts of an organic corrosion inhibitor, 5-8 parts of a nonionic surfactant, 8-12 parts of a chelating agent, 2-3 parts of a biological enzyme complex, 3-5 parts of nano-alumina, and 50-75 parts of water. Furthermore, the organic base is a mixture of tetramethylammonium hydroxide, lutidine, and ethanolamine. Furthermore, the weight ratio of tetramethylammonium hydroxide, lutidine, and ethanolamine is 1:(0.4-0.6):(0.1-0.2). The biological enzyme complex is a protease and lipase in a weight ratio of 1:(0.5-0.8).

[0031] The present application also provides a method for preparing the above-mentioned composite corrosion-inhibiting alkaline cleaning agent, comprising the following steps: first, mixing the organic base with water and stirring evenly at ≤40°C; then adding a nonionic surfactant and a chelating agent and stirring for 30-40 minutes; then adding the remaining components and ultrasonically dispersing for 20-30 minutes to obtain a composite corrosion-inhibiting alkaline cleaning agent.

[0032] In the present application, the CAS number of sodium polyepoxysuccinate is 51274-37-4; the CAS number of the benzotriazole derivative is benzotriazole-4-sulfonic acid, which is 26725-50-8; the CAS number of tetramethylammonium hydroxide is 75-59-2; the CAS number of lutidine is 583-61-9; the CAS number of ethanolamine is 141-43-5; the chelating agent is HEDP; the nonionic surfactant is dodecyl glucoside (APG-12); the CAS number of protease is 90336-06-0; and the CAS number of lipase is 9001-62-1. The raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.

[0033] The present application is further described in detail below with reference to embodiments and performance testing.

[0034] Examples 1-9 Examples 1-9 each provide a composite corrosion-inhibiting alkaline cleaning agent.

[0035] The difference between the above embodiments is that the addition amounts of the organic base and the organic corrosion inhibitor in the composite corrosion-inhibiting alkaline cleaning agent are shown in Table 1 below.

[0036] The preparation method of the composite corrosion-inhibiting alkaline cleaning agent provided in Example 1-9 includes the following steps: first, mixing the organic base (tetramethylammonium hydroxide) with 60g of water and stirring evenly at 25°C; then adding 7g of non-ionic surfactant APG-12 and 10g of chelating agent HEDP, and stirring for 30 minutes; then adding an organic corrosion inhibitor (a mixture of sodium polyepoxysuccinate and benzotriazole derivatives in a weight ratio of 1:3), 2.5g of a biological enzyme complex (a protease and lipase in a weight ratio of 1:0.6) and 4g of nano-alumina, and ultrasonically dispersing for 20 minutes to obtain a composite corrosion-inhibiting alkaline cleaning agent.

[0037] Table 1 Addition amount of organic base and organic corrosion inhibitor in Examples 1-9 Examples 10-11 Examples 10-11 each provide a composite corrosion-inhibiting alkaline cleaning agent.

[0038] The difference between the above embodiment and embodiment 3 is that the weight ratio of sodium polyepoxysuccinate and benzotriazole derivative in the organic corrosion inhibitor is shown in Table 2 below.

[0039] Table 2 Weight ratio of sodium polyepoxysuccinate and benzotriazole derivative in the organic corrosion inhibitor of Examples 10-11 / Weight ratio of sodium polyepoxysuccinate and benzotriazole derivative Example 3 1：3 Example 10 1：2.5 Example 11 1：3.5 Comparative Example 1 1：1 Comparative Example 2 1：5 Comparative Example 3 Only sodium polyepoxysuccinate Comparative Example 4 Only benzotriazole derivatives are used Examples 12-19 Examples 12-19 each provide a composite corrosion-inhibiting alkaline cleaning agent.

[0040] The difference between the above embodiment and embodiment 3 is: the type and ratio of the organic base, as shown in Table 3 below.

[0041] Table 3 Types and ratios of organic bases in Examples 12-19 Comparative Examples 1-4 Comparative Examples 1-4 respectively provide a composite corrosion-inhibiting alkaline cleaning agent.

[0042] The difference between the comparative example and Example 3 is that the type and ratio of the organic corrosion inhibitor are specifically shown in Table 2 above.

[0043] Comparative Example 5 Comparative Example 5 provides a composite corrosion-inhibiting alkaline cleaning agent.

[0044] The difference between the comparative example and Example 3 is that the organic base is replaced by sodium hydroxide.

[0045] Performance testing The composite corrosion-inhibiting alkaline cleaning agents obtained in Examples 1-19 and Comparative Examples 1-5 were tested for their reverse osmosis membrane cleaning effects. The specific process is as follows: (1) Cleaning: a composite corrosion-inhibiting alkaline cleaning agent was mixed with water in a volume ratio of 2:100 to obtain a mixed cleaning solution; the mixed cleaning solution was added to a reverse osmosis membrane treatment device (containing a BW30-400 reverse osmosis system membrane element with severe fouling) for circulation cleaning at a temperature of 25°C and a cleaning time of 1.5 h. The cleaning solution was then discharged, and the reverse osmosis membrane was rinsed with deionized water for 20 minutes.

[0046] (2) Test: The raw water was treated using the reverse osmosis membrane treatment device before and after the above treatment, and the produced water flow rate, the conductivity of the raw water and the produced water were detected respectively, and the desalination rate was calculated. The calculation formula is as follows: Desalination rate = (1-salt concentration in produced water / salt concentration in raw water) × 100%.

[0047] Table 4 Results of the test on the use of the composite corrosion-inhibiting alkaline cleaning agents obtained in Examples 1-19 and Comparative Examples 1-5 According to the test results in Table 4, after the reverse osmosis system membrane elements in the reverse osmosis membrane treatment device were cleaned using the composite corrosion-inhibiting alkaline cleaning agent provided in Examples 1-19 of the present application, the water production of the reverse osmosis membrane treatment device increased by 22.1-39.0%, and the desalination rate increased by 1.74-2.89%; while after the reverse osmosis system membrane elements in the reverse osmosis membrane treatment device were cleaned using the composite corrosion-inhibiting alkaline cleaning agent provided in Comparative Examples 1-4, the water production of the reverse osmosis membrane treatment device was only increased by 8.5-17.1%, and the desalination rate was only increased by 0.72-1.05%; after the reverse osmosis system membrane elements in the reverse osmosis membrane treatment device were cleaned using the composite corrosion-inhibiting alkaline cleaning agent provided in Comparative Example 5, although the water production of the reverse osmosis membrane treatment device was increased by 26.5%, the reverse osmosis membrane element was damaged and its desalination rate decreased by 4.24%. Therefore, it is explained that the present application uses a mixture of sodium polyepoxysuccinate and a benzotriazole derivative in a weight ratio of 1: (2.5-3.5) as an organic sustained-release agent and an organic base as the main base. The obtained composite corrosion-inhibiting alkaline cleaning agent can comprehensively and efficiently clean the pollutants deposited on the surface of the reverse osmosis membrane, restore or maintain the normal water flux and desalination performance of the reverse osmosis membrane, and will not cause membrane damage.

[0048] The test results of Examples 1-9 show that after the reverse osmosis system membrane elements in the reverse osmosis membrane treatment device are cleaned using the composite corrosion-inhibiting alkaline cleaning agent provided in Example 1, Example 5-6, and Example 9, the water production of the reverse osmosis membrane treatment device is increased by 22.1-24.2%, and the desalination rate is increased by 1.74-1.99%; and after the reverse osmosis system membrane elements in the reverse osmosis membrane treatment device are cleaned using the composite corrosion-inhibiting alkaline cleaning agent provided in Example 2-4 and Example 7-8, the water production of the reverse osmosis membrane treatment device is increased by 26.8-32.7% (≥25.0%), and the desalination rate is increased by 2.18-2.37% (≥2.00%). Therefore, it is explained that the present application further controls the addition amount of organic base to 15-23 parts and the addition amount of organic slow-release agent to 8-13 parts, and the obtained composite corrosion-inhibiting alkaline cleaning agent has a better cleaning effect on the contaminants on the surface of the reverse osmosis membrane.

[0049] The test results of Example 3 and Example 12-19 show that after the composite corrosion-inhibiting alkaline cleaning agent prepared in Example 3 and Example 12 uses tetramethylammonium hydroxide or lutidine and ethanolamine in a weight ratio of 1:0.3 as an organic base to clean the reverse osmosis system membrane element in the reverse osmosis membrane treatment device, the water production of the reverse osmosis membrane treatment device is only increased by 32.7-33.33%, and the desalination rate is only increased by 2.31-2.37%; Example 18-19 uses tetramethylammonium hydroxide, lutidine and ethanolamine in a weight ratio of 1:0.2:0.5 or tetramethylammonium hydroxide, lutidine and ethanolamine in a weight ratio of 1:1:1 as an organic base, and the composite corrosion-inhibiting alkaline cleaning agent prepared in Example 18-19 uses tetramethylammonium hydroxide, lutidine and ethanolamine in a weight ratio of 1:0.2:0.5 or tetramethylammonium hydroxide, lutidine and ethanolamine in a weight ratio of 1:1:1 as an organic base. After the corrosion-inhibiting alkaline cleaning agent is used to clean the reverse osmosis system membrane elements in the reverse osmosis membrane treatment device, the water production of the reverse osmosis membrane treatment device is only increased by 34.0-34.7%, and the desalination rate is only increased by 2.41-2.43%; while Examples 13-17 use tetramethylammonium hydroxide, dimethylpyridine and ethanolamine in a weight ratio of 1: (0.4-0.6): (0.1-0.2) as organic bases, and the prepared composite corrosion-inhibiting alkaline cleaning agent is used to clean the reverse osmosis system membrane elements in the reverse osmosis membrane treatment device. After that, the water production of the reverse osmosis membrane treatment device is increased by 37.6-39.0% (≥37.0%), and the desalination rate is increased by 2.62-2.89% (≥2.60%). Therefore, it is explained that the present application further uses tetramethylammonium hydroxide, dimethylpyridine and ethanolamine in a weight ratio of 1: (0.4-0.6): (0.1-0.2) as organic bases, and the prepared composite corrosion-inhibiting alkaline cleaning agent has a better cleaning effect on the pollutants on the surface of the reverse osmosis membrane, can more thoroughly restore the normal water flux and desalination performance of the reverse osmosis membrane, and will not cause membrane damage.

[0050] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A composite corrosion-inhibiting alkaline cleaning agent, characterized in that: The invention comprises the following components in parts by weight: 10-25 parts of an organic base, 5-15 parts of an organic corrosion inhibitor, 5-8 parts of a nonionic surfactant, 8-12 parts of a chelating agent, 2-3 parts of a biological enzyme complex, 3-5 parts of nano-alumina and 50-75 parts of water; The organic sustained-release agent is a mixture of sodium polyepoxysuccinate and a benzotriazole derivative in a weight ratio of 1:(2.5-3.5).

2. The composite corrosion-inhibiting alkaline cleaning agent according to claim 1, characterized in that: The composite corrosion-inhibiting alkaline cleaning agent comprises the following components in parts by weight: 15-23 parts of organic base, 8-13 parts of organic corrosion inhibitor, 5-8 parts of nonionic surfactant, 8-12 parts of chelating agent, 2-3 parts of biological enzyme complex, 3-5 parts of nano-aluminum oxide and 50-75 parts of water.

3. The composite corrosion-inhibiting alkaline cleaning agent according to claim 1, characterized in that: The organic base is selected from one or more of tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, picoline, lutidine, collidine, ethanolamine and diethanolamine.

4. The composite corrosion-inhibiting alkaline cleaning agent according to claim 3, characterized in that: The organic base is a mixture of tetramethylammonium hydroxide, lutidine and ethanolamine.

5. The composite corrosion-inhibiting alkaline cleaning agent according to claim 4, characterized in that: The weight ratio of the tetramethylammonium hydroxide, lutidine and ethanolamine is 1: (0.4-0.6): (0.1-0.2).

6. The composite corrosion-inhibiting alkaline cleaning agent according to any one of claims 1 to 5, characterized in that: The nonionic surfactant is dodecyl glycoside.

7. The composite corrosion-inhibiting alkaline cleaning agent according to any one of claims 1 to 5, characterized in that: The chelating agent is HEDP.

8. The composite corrosion-inhibiting alkaline cleaning agent according to any one of claims 1 to 5, characterized in that: The biological enzyme complex is protease and lipase.

9. The method for preparing the composite corrosion-inhibiting alkaline cleaning agent according to any one of claims 1 to 8, characterized in that: The following steps are involved: First, the organic base is mixed with water and stirred evenly at ≤40°C; then a nonionic surfactant and a chelating agent are added and stirred for 30-40 minutes; then the remaining components are added and ultrasonically dispersed for 20-30 minutes to obtain a composite corrosion-inhibiting alkaline cleaning agent.

10. Use of the composite corrosion-inhibiting alkaline cleaning agent according to any one of claims 1 to 8 in cleaning reverse osmosis membrane elements.

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