Reverse osmosis membrane repairing agent, preparation method and repairing method

Abstract

The invention relates to a reverse osmosis membrane repairing agent, a preparation method and a repairing method. The reverse osmosis membrane repairing agent is prepared from ethyl acetoacetate, glycerin, dimethyl sulfoxide, acetic acid and deionized water. The reverse osmosis membrane repairing agent is diluted, a reverse osmosis membrane is pre-cleaned and installed in a membrane cleaning device, and the reverse osmosis membrane with the desalination rate not smaller than 80% is repaired. According to the method, the desalination rate of the membrane with the desalination rate not smaller than 80% can be recovered to 95% or above, the influence on the water yield of the membrane is extremely small, the effect of the repairing agent is good, and the membrane is very stable after the desalination rate is recovered.

Description

Technical Field

[0001] The present disclosure relates to the field of reverse osmosis technology, and in particular to a reverse osmosis membrane repair agent, a preparation method and a repair method. Background Art

[0002] In recent years, with the gradual expansion of the application of reverse osmosis technology, the use of reverse osmosis membranes has also greatly increased. During the use of reverse osmosis membranes, scaling is a common phenomenon, and conventional membrane cleaning agents on the market will cause certain damage to the reverse osmosis membrane, resulting in a decrease in the desalination rate of the reverse osmosis membrane, which seriously affects the service life of the reverse osmosis membrane. At the same time, membrane pollution and membrane oxidation will reduce the service life of the reverse osmosis membrane, which will usually be scrapped in about three years. This has gradually increased the cost of using reverse osmosis membranes, and the treatment of discarded reverse osmosis membranes has also brought a great burden to the environment, and it is also a waste of resources.

[0003] Repairing the reverse osmosis membrane can not only reduce the purchase cost of new membranes, but also reduce the harm of discarded reverse osmosis membranes to the environment. There are two main problems with the existing membrane repair agents on the market. First, after the repair of the membrane repair agent, although the desalination rate of the reverse osmosis membrane is restored, the flux of the reverse osmosis membrane is greatly reduced. Secondly, there is the problem of the stability of the reverse osmosis membrane repair layer. Although the membrane desalination rate has rebounded after repair, it will soon return to its original state, and the desalination rate has not been really improved.

[0004] In view of the above situation, the prior art provides some agents for improving the membrane desalination rate, thereby restoring the membrane desalination rate to a certain extent. For example: Chinese patent application document CN115105962A discloses a method for repairing waste reverse osmosis membranes, which method includes: (1) using a mixed solution containing a cross-linking agent and a catalyst to soak the waste reverse osmosis membrane element for a first cycle to obtain a first soaked object; (2) using a solution containing an alcohol compound to soak the first soaked object for a second cycle to obtain a second soaked object, and then washing with water to obtain a repaired reverse osmosis membrane element. The repair method provided by the invention can make the repaired reverse osmosis membrane element have better membrane separation performance, but the membrane flux decreases slightly and the repair time is too long. Other data show that most existing repair agents have the phenomenon of decreased flow after repair and fast rebound after repair.

[0005] The Chinese patent application document CN112588120A discloses a reverse osmosis membrane repair agent, preparation method and repair method developed by our company, which includes the following steps: step 1, diluting the reverse osmosis membrane repair agent or using the stock solution as a working agent according to the current desalination rate of the reverse osmosis membrane and the required desalination rate to be restored; step 2, pre-cleaning the reverse osmosis membrane; step 3, heating the working agent obtained in step 1 to 30-35°C; step 4, installing the reverse osmosis membrane in a membrane cleaning device, sending the heated working agent in step 3 into the membrane cleaning device, controlling the temperature of the working agent to 30-35°C, first circulating and cleaning for 30-60 minutes, and then soaking for 30-60 minutes. The reverse osmosis membrane element repaired by this method has been verified to be very stable after the membrane desalination rate is restored, and the system has been running continuously for 3 months without a decrease in desalination rate, but the use of a strong alkaline agent to clean the membrane will significantly reduce its desalination rate, and when the number of membranes in a single membrane system is large (>60), the flow rate will drop by about 15% after repair. Summary of the invention

[0006] The present invention discloses a reverse osmosis membrane repair agent, a preparation method and a repair method to solve the following problems: the existing membrane cleaning agent may cause certain damage to the reverse osmosis membrane, resulting in a decrease in the desalination rate of the reverse osmosis membrane, seriously affecting the service life of the reverse osmosis membrane, and the like.

[0007] According to one aspect of the present disclosure, a reverse osmosis membrane repair agent is provided, in which the contents of the raw material components are as follows: ethyl acetoacetate 10%-15%; glycerol 0.5%-1%; dimethyl sulfoxide 9%-11%; acetic acid 10%-15%; and the balance is deionized water.

[0008] Preferably, the contents of the raw material components are: ethyl acetoacetate 10%; glycerol 1%; dimethyl sulfoxide 9%; acetic acid 10%; and the balance is deionized water.

[0009] Preferably, after adding the raw material components of the reverse osmosis membrane repair agent into a container, the mixture is stirred at room temperature for 1-2 hours to obtain the reverse osmosis membrane repair agent.

[0010] Preferably, the reverse osmosis membrane repair agent is used to repair a reverse osmosis membrane with a desalination rate of not less than 80%.

[0011] Preferably, the repair method comprises the following steps: S10, diluting the reverse osmosis membrane repair agent to 10%-15% as a working agent; S20, pre-cleaning the reverse osmosis membrane; S30, installing the reverse osmosis membrane in a membrane cleaning device, sending the working agent in S10 into the membrane cleaning device, first circulating the cleaning for 1-2 hours, and then soaking for 1-2 hours.

[0012] Preferably, after S30, the following steps are further included: Use deionized water or tap water to repeatedly clean the soaked reverse osmosis membrane.

[0013] Preferably, the reverse osmosis membrane is pre-cleaned with deionized water or tap water.

[0014] The beneficial effects of the present disclosure are: The reverse osmosis membrane repair agent, preparation method and repair method disclosed in the present invention have a simple preparation method and can be prepared at room temperature. The desalination rate of a membrane with a desalination rate greater than 80% can be restored to more than 95%, with minimal impact on the membrane water production. The repair agent has a good effect. The membrane desalination rate is very stable after recovery, and the system has been running continuously for 3 months without any decrease in desalination rate. DETAILED DESCRIPTION

[0015] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following examples specifically describe the reverse osmosis membrane repair agent, preparation method and repair method of the present invention.

[0016] Existing membrane cleaning agents can cause certain damage to the reverse osmosis membrane, resulting in a decrease in the desalination rate of the reverse osmosis membrane, which seriously affects the service life of the reverse osmosis membrane. In order to solve these problems, a reverse osmosis membrane repair agent, a preparation method and a repair method are proposed to improve the desalination rate of the reverse osmosis membrane without reducing the membrane flux.

[0017] Example 1 The disclosed embodiment of the present invention discloses a reverse osmosis membrane repair agent, in which the contents of various raw material components are as follows: ethyl acetoacetate 10%-15%; glycerol 0.5%-1%; dimethyl sulfoxide 9%-11%; acetic acid 10%-15%; and the balance is deionized water.

[0018] In multiple groups of experiments, the content of each raw material component is preferably: ethyl acetoacetate 10%; glycerol 1%; dimethyl sulfoxide 9%; acetic acid 10%; and the balance is deionized water.

[0019] Example 2 The disclosed embodiment also provides a method for preparing a reverse osmosis membrane repair agent, the preparation method comprising: adding each raw material component of the reverse osmosis membrane repair agent in Example 1 into a container, stirring at room temperature for 1-2 hours, to obtain the reverse osmosis membrane repair agent.

[0020] Example 3 The embodiment of the present disclosure provides a method for repairing a reverse osmosis membrane, using the reverse osmosis membrane repair agent prepared in Example 2 to repair a reverse osmosis membrane with a desalination rate of not less than 80%. The desalination rate of the reverse osmosis membrane must be not less than 80% under standard conditions, otherwise the repair cannot be performed or the repair effect is poor.

[0021] The repair method in the embodiment of the present disclosure comprises the following steps: S10, diluting the reverse osmosis membrane repair agent or using the stock solution as a working agent according to the current desalination rate of the reverse osmosis membrane and the required desalination rate to be restored; The reverse osmosis membrane repair agent is diluted to 10%-15% as a working agent.

[0022] S20, pre-cleaning the reverse osmosis membrane; Among them, the specific treatment method and cleaning time of pre-cleaning can be carried out according to actual conditions.

[0023] S30, installing the reverse osmosis membrane in a membrane cleaning device, sending the working agent of S20 into the membrane cleaning device, first circulating the cleaning for 1-2 hours, and then soaking for 1-2 hours.

[0024] After S30, the following steps are also included: Use deionized water or tap water to repeatedly clean the soaked reverse osmosis membrane.

[0025] The present disclosure also verifies the effectiveness and stability of the reverse osmosis membrane repair agent and the reverse osmosis membrane repair method as follows: The reverse osmosis membrane repair agent in Example 1 and the repair method in Example 3 were used to conduct comparative tests with other methods. The comparative test data are shown in the following table: (The test conditions in the table are: the test is conducted under the conditions of an inlet water pressure of 10 kg and a sodium chloride water conductivity of 2000 μS / cm)

[0026] According to the data in the above table, the reverse osmosis membrane repair agent and the above repair method in this embodiment can restore the desalination rate of the membrane with a desalination rate greater than 80% to more than 95%, with minimal impact on the membrane water production. The membrane desalination rate is very stable after recovery, and the system has been running continuously for 3 months without any decrease in desalination rate. Compared with the above other repair agents, the effect is good.

[0027] The embodiments of the present disclosure have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A reverse osmosis membrane repair agent, characterized in that: The contents of the raw material components in the reverse osmosis membrane repair agent are as follows: ethyl acetoacetate 10%-15%; glycerol 0.5%-1%; dimethyl sulfoxide 9%-11%; acetic acid 10%-15%; and the balance is deionized water.

2. The reverse osmosis membrane repairing agent according to claim 1, characterized in that: The content of each raw material component is preferably: ethyl acetoacetate 10%; glycerol 1%; dimethyl sulfoxide 9%; acetic acid 10%; and the balance is deionized water.

3. A method for preparing a reverse osmosis membrane repair agent, characterized in that: After adding the raw material components of the reverse osmosis membrane repair agent according to claim 1 or 2 into a container, stirring at room temperature for 1-2 hours to obtain the reverse osmosis membrane repair agent.

4. A method for repairing a reverse osmosis membrane, characterized in that: The reverse osmosis membrane repair agent as claimed in claim 1 or 2 is used to repair a reverse osmosis membrane with a desalination rate of not less than 80%.

5. The repair method according to claim 4, characterized in that: The repair method comprises the following steps: S10, diluting the reverse osmosis membrane repair agent to 10%-15% as a working agent; S20, pre-cleaning the reverse osmosis membrane; S30, installing the reverse osmosis membrane in a membrane cleaning device, sending the working agent in S10 into the membrane cleaning device, first circulating the cleaning for 1-2 hours, and then soaking for 1-2 hours.

6. The repair method according to claim 4, characterized in that: After S30, the following steps are also included: Use deionized water or tap water to repeatedly clean the soaked reverse osmosis membrane.

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