Reverse osmosis membrane PAC pollution cleaning agent and preparation method thereof

Abstract

The invention discloses a reverse osmosis membrane PAC pollution cleaning agent and a preparation method thereof. The reverse osmosis membrane PAC pollution cleaning agent comprises the following raw materials in percentage by weight: 10-20% of a chelating agent, 0.5-2% of a stripping agent, 1-5% of a penetrating agent, 1-5% of a dispersing agent and the balance of water. The invention relates to the technical field of cleaning agents. According to the reverse osmosis membrane PAC pollution cleaning agent and the preparation method thereof, the chelating agent, the penetrating agent and the stripping agent serve as main components, PAC colloidal dirt on the surface of a membrane can be safely, rapidly and efficiently removed through the synergistic effect of penetrating, softening, dispersing and stripping, chelating and the like, the membrane flux is effectively recovered, secondary pollution is not likely to be caused, meanwhile, PAC colloid can be dispersed, and the cleaning effect is good. And the film cannot be scratched in the cleaning process, the dissolution rate of PAC scale can be greatly increased, and the cleaning efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of cleaning agents, in particular to a reverse osmosis membrane PAC pollution cleaning agent and a preparation method thereof. Background Art

[0002] Due to their high water permeability, efficient filtration, durability, low energy consumption, and wide applicability, reverse osmosis membranes are widely used in the power, petrochemical, steel, electronics, pharmaceuticals, food and beverage, municipal administration, and environmental protection industries. They play a particularly important role in desalination of seawater and brackish water, production of boiler feed water, industrial pure water, electronic-grade ultrapure water, production of pure drinking water, wastewater treatment, and specialized separation processes.

[0003] During the use of reverse osmosis membrane equipment, in addition to the normal degradation of membrane performance, it can also be affected by external contamination, resulting in severe degradation of reverse osmosis membrane performance. Common membrane contamination mainly includes chemical scale contamination, organic and colloid contamination, microbial contamination, etc. Currently, our traditional cleaning methods are acid-base cleaning or acid-base alternating cleaning. Acid cleaning can remove most chemical scale contamination, and alkaline cleaning can remove most organic and microbial contamination. However, for some flocculant colloid contamination, such as PAC flocculant contamination, conventional cleaning agents cannot completely clean it. Therefore, the present invention provides a reverse osmosis membrane PAC contamination cleaning agent and its preparation method to solve the above problems. Summary of the Invention

[0004] (1) Technical problems solved

[0005] In view of the deficiencies in the prior art, the present invention provides a reverse osmosis membrane PAC contamination cleaning agent and a preparation method thereof, which solves the problems mentioned in the above background technology.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solution: a reverse osmosis membrane PAC contamination cleaning agent, which comprises the following raw materials in weight percentage: 10wt% to 20wt% of a chelating agent, 0.5wt% to 2wt% of a stripping agent, 1wt% to 5wt% of a penetrant, 1wt% to 5wt% of a dispersant, 6wt% to 8wt% of a surfactant, 1wt% to 3wt% of a bactericide, and the remainder is water.

[0008] Preferably, the chelating agent is one of tetrasodium ethylenediaminetetraacetic acid, sodium hexametaphosphate, and nitrilotriacetate, or a mixture of more than one of the above.

[0009] Preferably, the chelating agent is one of tetrasodium ethylenediaminetetraacetic acid, sodium hexametaphosphate, and nitrilotriacetate, or a mixture of more than one of the above.

[0010] Preferably, the dispersant is sodium lauryl sulfate, fatty acid polyethylene glycol ester, or a mixture of the two.

[0011] Preferably, the dispersant is sodium lauryl sulfate, fatty acid polyethylene glycol ester, or a mixture of the two.

[0012] Preferably, the fungicide is any one or more mixtures of formaldehyde, isothiazolin, sodium bisulfite, and glutaraldehyde.

[0013] Preferably, the cleaning steps using the cleaning agent are:

[0014] Step 1: Turn on the feed pump, pump in the cleaning agent, circulate and clean for 10 minutes, then turn on the high-pressure pump, circulate and clean at high pressure for about 30 minutes, and finally turn off the high-pressure pump and soak at a low flow rate for 3 hours;

[0015] Step 2: After soaking, rinse with tap water and drain the concentrated water until the pH of the concentrated water is neutral and then stop rinsing.

[0016] A method for preparing a PAC contamination cleaning agent for a reverse osmosis membrane comprises the following steps: heating water in a reaction vessel, then sequentially adding raw materials into the reaction vessel according to a proportion, stirring sufficiently, cooling, and adjusting the pH of the solution to obtain the PAC contamination cleaning agent for a reverse osmosis membrane.

[0017] Preferably, the water is heated to 45° C. to 60° C., and the pH is adjusted to 8.0 to 10.0.

[0018] (3) Beneficial effects

[0019] The present invention provides a PAC contamination cleaning agent for reverse osmosis membranes and a preparation method thereof. Compared with existing technologies, the present invention has the following advantages: The PAC contamination cleaning agent for reverse osmosis membranes and its preparation method, using a chelating agent, a penetrant, and a stripping agent as main components, can safely, quickly, and efficiently remove PAC colloid fouling from the membrane surface through the synergistic effects of penetration, softening, dispersion stripping, and chelation, effectively restoring membrane flux and minimizing secondary contamination. Furthermore, the agent disperses the PAC colloid, preventing membrane scratches during the cleaning process, and significantly increases the dissolution rate of PAC scale, significantly improving cleaning efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A reverse osmosis membrane surface morphology diagram provided by a reverse osmosis membrane PAC pollution cleaning agent and a preparation method thereof of the present invention;

[0021] Figure 2 This is a scanning electron microscope image of a reverse osmosis membrane provided by the present invention, a PAC pollution cleaning agent for reverse osmosis membrane and a preparation method thereof. DETAILED DESCRIPTION

[0022] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0023] The embodiments of the present invention provide the following technical solutions:

[0024] Example 1: The reverse osmosis membrane PAC pollution cleaning agent includes the following raw materials in weight percentage: 10wt% of tetrasodium salt of ethylenediaminetetraacetic acid, 2wt% of 30% concentration hydrogen peroxide, 5wt% of fatty alcohol polyoxyethylene ether, 5wt% of sodium lauryl sulfate, 8wt% of sodium lauryl sulfate, 3wt% of isothiazolinone, and 67wt% of water.

[0025] A method for preparing a PAC contamination cleaning agent for a reverse osmosis membrane comprises the following steps: heating water to 45°C in a reaction vessel, then sequentially adding raw materials according to a proportion into the reaction vessel, stirring sufficiently, cooling, and adjusting the pH of the solution to 8.0 to obtain the PAC contamination cleaning agent for a reverse osmosis membrane.

[0026] Example 2: The reverse osmosis membrane PAC pollution cleaning agent includes the following raw materials in weight percentage: 15wt% of sodium hexametaphosphate, 1.5wt% of sodium percarbonate, 3wt% of sodium di-sec-octyl maleate sulfonate, 3wt% of fatty acid polyethylene glycol ester, 7wt% of sodium dodecylbenzenesulfonate, 2wt% of sodium bisulfite, and 68.5wt% of water.

[0027] A method for preparing a PAC contamination cleaning agent for a reverse osmosis membrane comprises the following steps: heating water to 50° C. in a reaction vessel, then sequentially adding raw materials according to a proportion into the reaction vessel, stirring sufficiently, cooling the mixture, and adjusting the pH of the solution to 9.0 to obtain the PAC contamination cleaning agent for a reverse osmosis membrane.

[0028] Example 3: The reverse osmosis membrane PAC contamination cleaning agent includes the following raw materials in weight percentage: 20wt% of nitrilotriacetate, 0.5wt% of 30% concentration hydrogen peroxide, 1wt% of perfluorohexyl polyoxyethylene ether, 1wt% of fatty acid polyethylene glycol ester, 6wt% of sodium lauryl sulfate, 1wt% of glutaraldehyde, and 70.5wt% of water.

[0029] A method for preparing a PAC contamination cleaning agent for a reverse osmosis membrane comprises the following steps: heating water to 60° C. in a reaction vessel, then sequentially adding raw materials into the reaction vessel according to a proportion, stirring sufficiently, cooling the mixture, and adjusting the pH of the solution to 10.0 to obtain the PAC contamination cleaning agent for a reverse osmosis membrane.

[0030] Example 4: The reverse osmosis membrane PAC contamination cleaning agent comprises the following raw materials in weight percentage: 10 wt% of a mixture of tetrasodium ethylenediaminetetraacetic acid and sodium hexametaphosphate, 2 wt% of a mixture of 30% concentration hydrogen peroxide and sodium percarbonate, 5 wt% of a mixture of fatty alcohol polyoxyethylene ether and sodium di-secondary octyl maleate sulfonate, 5 wt% of a mixture of sodium lauryl sulfate and fatty acid polyethylene glycol ester, 8 wt% of sodium lauryl sulfate, 3 wt% of a mixture of isothiazolinyl and sodium bisulfite, and 67 wt% of water.

[0031] A method for preparing a PAC contamination cleaning agent for a reverse osmosis membrane comprises the following steps: heating water to 45°C in a reaction vessel, then sequentially adding raw materials according to a proportion into the reaction vessel, stirring sufficiently, cooling, and adjusting the pH of the solution to 8.0 to obtain the PAC contamination cleaning agent for a reverse osmosis membrane.

[0032] For this purpose, the agent prepared by this technical solution is suitable for offline cleaning; the reverse osmosis membrane contaminated by PAC scale is first subjected to conventional acid and alkali washing, and then cleaned with this agent. The cleaning addition amount of this agent is 1 to 5 kilograms per liter of water. When the fouling is serious, the dosage can be increased appropriately.

[0033] Simulated sewage pollution: The sewage used was prepared by a certain amount of food-grade PAC and sodium alginate in sodium chloride solution. The pollution experiment was carried out at a temperature of 30°C and a pressure of 2.5 MPa.

[0034] The specific steps are:

[0035] (1) Add a certain amount of food-grade PAC and sodium alginate to a 1000 mL beaker and add an appropriate amount of tap water. Place the beaker in a CNC ultrasonic cleaner and stir gently with a glass rod to prevent the contaminants from caking at the bottom of the beaker. Ultrasonicate at 30°C for 30 minutes to fully dissolve the food-grade PAC and sodium alginate. Pour the mixture into a specific container and adjust the volume to 10 L. Add 120 g of sodium chloride to make a 12000 ppm NaCl solution, stir for 15 minutes, and let it stand for 4 hours for use.

[0036] (2) Cut out a circular membrane sheet (D-97mm) of the same size as the flat membrane assembly, soak it in water at room temperature for 1 hour to moisten the membrane sheet, then remove the membrane sheet, rinse it with deionized water, place it in the flat membrane assembly and fix it;

[0037] (3) Pour the prepared organic contamination solution into the water tank of the membrane evaluation device and turn on the temperature controller to raise the temperature and stabilize it to 30°C;

[0038] (4) The hydraulic diaphragm metering pump was turned on to conduct an organic contamination experiment on the membrane. The concentrated water and the produced water were returned to the water tank of the membrane evaluation device at the same time. Since the diaphragm area was very small, the incoming water was considered to have a constant composition. The operation was carried out for 10.5 h (the flux decreased by 23%).

[0039] At the same time, the contents not described in detail in this specification belong to the existing technology well known to those skilled in the art.

[0040] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0041] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A reverse osmosis membrane PAC pollution cleaning agent, characterized in that: The reverse osmosis membrane PAC pollution cleaning agent comprises the following raw materials in percentage by weight: 10wt% to 20wt% of a chelating agent, 0.5wt% to 2wt% of a stripping agent, 1wt% to 5wt% of a penetrant, 1wt% to 5wt% of a dispersant, 6wt% to 8wt% of a surfactant, 1wt% to 3wt% of a bactericide, and the remainder is water.

2. A reverse osmosis membrane PAC pollution cleaning agent according to claim 1, characterized in that: The chelating agent is one of tetrasodium ethylenediaminetetraacetic acid, sodium hexametaphosphate, and nitrilotriacetate, or a mixture of more than one of the above.

3. A reverse osmosis membrane PAC pollution cleaning agent according to claim 1, characterized in that: The stripping agent is 30% concentration hydrogen peroxide, sodium percarbonate, or a mixture of the two.

4. A reverse osmosis membrane PAC pollution cleaning agent according to claim 1, characterized in that: The penetrant is one or a mixture of fatty alcohol polyoxyethylene ether, sodium di-secondary octyl maleate sulfonate, and perfluorohexyl polyoxyethylene ether.

5. A reverse osmosis membrane PAC pollution cleaning agent according to claim 1, characterized in that: The dispersant is sodium lauryl sulfate, fatty acid polyethylene glycol ester, or a mixture of the two.

6. The method for preparing a PAC pollution cleaning agent for reverse osmosis membrane according to claim 1, wherein: The surfactant is any one of sodium lauryl sulfate and sodium dodecylbenzene sulfonate.

7. The reverse osmosis membrane PAC pollution cleaning agent according to claim, characterized in that: The bactericide is any one or more mixtures of formaldehyde, isothiazolin, sodium bisulfite and glutaraldehyde.

8. The reverse osmosis membrane PAC pollution cleaning agent according to claim, characterized in that: The cleaning steps using this cleaning agent are: Step 1: Turn on the feed pump, pump in the cleaning agent, circulate and clean for 10 minutes, then turn on the high-pressure pump, circulate and clean at high pressure for about 30 minutes, and finally turn off the high-pressure pump and soak at a low flow rate for 3 hours; Step 2: After soaking, rinse with tap water and drain the concentrated water until the pH of the concentrated water is neutral and then stop rinsing.

9. A method for preparing a PAC pollution cleaning agent for reverse osmosis membranes according to any one of claims 1 to 7, characterized in that: The specific preparation method includes the following steps: heating water in a reaction container, then sequentially adding raw materials into the reaction container according to a proportion, stirring sufficiently, cooling, and adjusting the pH of the solution to obtain a reverse osmosis membrane PAC pollution cleaning agent.

10. The method for preparing a PAC pollution cleaning agent for reverse osmosis membrane according to claim 8, characterized in that: Heat water to 45°C to 60°C, and adjust the pH to 8.0 to 10.0.

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