Preparation method of anti-microbial pollution reverse osmosis membrane

Abstract

The invention discloses a preparation method of an anti-microbial pollution reverse osmosis membrane, and relates to the technical field of reverse osmosis membranes. Comprising the following steps: step 1, immersing the membrane surface of a base membrane into a water-phase solution containing a polyamine monomer, so that pores of the base membrane are filled with the water-phase solution; step 2, after removing the redundant aqueous phase solution, immersing the surface of the base membrane into an oil phase solution containing trimesoyl chloride; 3, after the reaction is completed, the membrane is put into a drying oven to be dried, and an oil-phase solvent is removed; 4, sequentially immersing the membrane into a citric acid solution, pure water and a glycerol water solution for cleaning, and drying again; and 5, immersing the membrane surface into the antibacterial coating liquid, and drying to obtain the reverse osmosis membrane capable of resisting microbial pollution. According to the preparation method, a proper amount of the surfactant is added into the water phase solution, and diffusion of a water phase monomer to an oil phase can be promoted during interfacial polymerization reaction, so that the surface roughness of a generated polyamide layer is increased, the surface area is increased, and coating of more antibacterial coatings is facilitated while the flux of the membrane is improved.

Description

Technical Field

[0001] The invention relates to the technical field of reverse osmosis membranes, and in particular to a method for preparing a reverse osmosis membrane resistant to microbial contamination. Background Art

[0002] Reverse osmosis membrane is an artificial semipermeable membrane with certain characteristics made by simulating biological semipermeable membrane. It is the core component of reverse osmosis technology. The principle of reverse osmosis technology is to separate these substances and water under the action of higher osmotic pressure than the solution, based on the fact that other substances cannot pass through the semipermeable membrane. The pore size of the reverse osmosis membrane is very small, so it can effectively remove dissolved salts, colloids, microorganisms, organic matter, etc. in water.

[0003] During the use of reverse osmosis membranes, performance loss may occur due to membrane contamination, until the membrane cannot be used. There are many types of membrane contamination, among which inorganic salt scaling and microbial contamination are the two most common forms of contamination. Inorganic salt scaling can be well removed by acid washing, but once microbial contamination forms a biofilm, it is difficult to remove. Therefore, for microbial contamination, we can only prevent it in advance and do a good job of pre-treating the incoming water to avoid the formation of biofilm. Most of the existing pretreatment methods are chlorination for sterilization, but chlorine has a strong destructive effect on the polyamide layer, and the concentration must be strictly controlled. Therefore, how to prepare a membrane that reduces or avoids microbial contamination during use is a technical problem that urgently needs to be solved in the industry. Summary of the invention

[0004] In view of the above problems, the present invention provides a method for preparing an anti-microbial contamination reverse osmosis membrane which is economical, stable and effectively avoids microbial contamination of the membrane during use.

[0005] The technical solution of the present invention is: A method for preparing a reverse osmosis membrane resistant to microbial contamination comprises the following steps: Step 1, immersing the surface of the base film in an aqueous solution containing a polyamine monomer so that the pores are filled with the aqueous solution; Step 2, after removing the excess aqueous solution, immersing the base film surface in an oil phase solution containing trimesoyl chloride; Step 3: After the reaction is completed, the membrane is placed in an oven for drying to remove the oil phase solvent; Step 4, immersing the membrane in citric acid solution, pure water, and glycerol aqueous solution in turn for cleaning, and drying again; Step 5: After immersing the membrane surface in the antibacterial coating solution, drying it, a reverse osmosis membrane resistant to microbial contamination is obtained.

[0006] Specifically, the aqueous phase solution preparation method is to add polyamine monomers and surfactants into pure water and stir until dissolved.

[0007] Specifically, the polyamine monomer is m-phenylenediamine, and the concentration is 2-5%.

[0008] Specifically, the surfactant is one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate, and the concentration is 0.01-0.05%.

[0009] Specifically, the oil phase solution is prepared by adding trimesoyl chloride to the oil phase solvent and stirring until dissolved; The concentration of trimesoyl chloride is 0.05-0.3%.

[0010] Specifically, the concentration of the citric acid solution is 5-10%.

[0011] Specifically, the concentration of the glycerol aqueous solution is 5-10%.

[0012] Specifically, the preparation method of the antibacterial coating is: Add sodium dodecyl sulfate into pure water, stir until completely dissolved, then add mugwort extract and stir evenly, then add hydrochloric acid, glutaraldehyde and PVA solution in sequence and stir evenly.

[0013] Specifically, the concentration of the wormwood extract is 0.5-1.5%.

[0014] Specifically, the concentration of sodium dodecyl sulfate is 0.05-0.1%.

[0015] The present invention adds an appropriate amount of surfactant to the aqueous phase solution, which will promote the diffusion of aqueous phase monomers into the oil phase during the interfacial polymerization reaction, thereby increasing the surface roughness and surface area of ​​the generated polyamide layer, improving the membrane flux and helping to apply more antibacterial coatings; the wormwood extract has good bactericidal and antibacterial properties and can prevent the growth and reproduction of microorganisms on the polyamide surface. DETAILED DESCRIPTION

[0016] The embodiments of the present invention are described in detail below.

[0017] A method for preparing a reverse osmosis membrane resistant to microbial contamination comprises the following steps: Step 1, immersing the surface of the base film in an aqueous solution containing a polyamine monomer so that the pores are filled with the aqueous solution; The aqueous phase solution is prepared by adding a polyamine monomer and a surfactant into pure water and stirring until dissolved. The polyamine monomer is m-phenylenediamine with a concentration of 2-5%. The surfactant is one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate with a concentration of 0.01-0.05%.

[0018] Step 2, after removing the excess aqueous solution, immersing the base film surface in an oil phase solution containing trimesoyl chloride; The oil phase solution is prepared by adding trimesoyl chloride to the oil phase solvent and stirring until dissolved; The concentration of trimesoyl chloride is 0.05-0.3%.

[0019] The oil phase solvent includes ethylcyclohexane or n-hexane.

[0020] Step 3: After the reaction is completed, the membrane is placed in an oven for drying to remove the oil phase solvent; Step 4: Immerse the membrane in citric acid solution, pure water, and glycerol aqueous solution in turn for cleaning, and then dry it again; the concentration of the citric acid solution is 5-10%. The concentration of the glycerol aqueous solution is 5-10%.

[0021] Step 5: After immersing the membrane surface in the antibacterial coating solution, drying it, a reverse osmosis membrane resistant to microbial contamination is obtained.

[0022] The preparation method of the antibacterial coating is as follows: Add 0.05-0.1% sodium dodecyl sulfate into pure water, stir until completely dissolved, then add mugwort extract and stir evenly. Then add hydrochloric acid, glutaraldehyde and PVA solution in sequence and stir evenly.

[0023] The concentration of hydrochloric acid is 0.5-1%; the concentration of glutaraldehyde is 0.5-1%; the concentration of PVA solution is 1-3%.

[0024] The concentration of wormwood extract is 0.5-1.5%.

[0025] The preparation steps of the wormwood extract are as follows: clean the wormwood and grind it into powder; add 5 owt% ethanol aqueous solution to the powder, soak it at 60-80°C for 5 hours, filter the residue to obtain a filtrate; evaporate and concentrate the filtrate, and spray dry it. The powder obtained by drying is the wormwood extract.

[0026] Example 1 S1: Immerse the surface of the basement membrane in an aqueous solution containing 3% m-phenylenediamine, so that its pores are filled with the aqueous solution; S2: After removing the excess aqueous solution, immerse the base film surface in an oil phase solution containing 0.15% trimesoyl chloride; S3: After the reaction is completed, the membrane is placed in an oven for drying to remove the oil phase solvent; S4: The membrane is sequentially immersed in 6% citric acid solution, pure water, and 5% glycerol aqueous solution for cleaning, and then dried again.

[0027] S5: After the membrane surface is immersed in the antibacterial coating liquid, it is dried to obtain a reverse osmosis membrane that is resistant to microbial contamination.

[0028] Preparation of antibacterial coating: add 5g sodium dodecyl sulfate to 8kg pure water, stir until completely dissolved, then add 100g wormwood extract, stir evenly, then add 60g hydrochloric acid, 120g 50% glutaraldehyde aqueous solution, 2kg 10% PVA solution in sequence, and stir evenly; Example 2 S1: Immerse the surface of the base membrane in an aqueous solution containing 3% m-phenylenediamine and 0.02% sodium dodecyl sulfate, so that its pores are filled with the aqueous solution; S2: After removing the excess aqueous solution, immerse the base film surface in an oil phase solution containing 0.15% trimesoyl chloride; S3: After the reaction is completed, the membrane is placed in an oven for drying to remove the oil phase solvent; S4: The membrane is sequentially immersed in 6% citric acid solution, pure water, and 5% glycerol aqueous solution for cleaning, and then dried again.

[0029] S5: After the membrane surface is immersed in the antibacterial coating liquid, it is dried to obtain a reverse osmosis membrane that is resistant to microbial contamination.

[0030] Preparation of antibacterial coating: add 5g sodium dodecyl sulfate to 8kg pure water, stir until completely dissolved, then add 100g wormwood extract, stir evenly, then add 60g hydrochloric acid, 120g 50% glutaraldehyde aqueous solution, 2kg 10% PVA solution in sequence, and stir evenly; Comparative Example 1 S1: Immerse the surface of the basement membrane in an aqueous solution containing 3% m-phenylenediamine, so that its pores are filled with the aqueous solution; S2: After removing the excess aqueous solution, immerse the base film surface in an oil phase solution containing 0.15% trimesoyl chloride; S3: After the reaction is completed, the membrane is placed in an oven for drying to remove the oil phase solvent; S4: The membrane is sequentially immersed in 6% citric acid solution, pure water, and 5% glycerol aqueous solution for cleaning, and then dried again.

[0031] S5: After immersing the membrane surface in the PVA solution, drying it.

[0032] Preparation of PVA solution: Take 8kg pure water, add 60g hydrochloric acid, 120g 50% glutaraldehyde aqueous solution, and 2kg 10% PVA solution in sequence, and stir evenly; The membranes prepared by the above three methods were sampled and tested for their filtration and antibacterial properties. The filtration performance test conditions were: test pressure 225psi, test solution 2000ppmNaCl, temperature 25℃. The antibacterial performance was tested in accordance with GB / T20944.1--2007. The data are as follows: Example 1: Desalination rate 99.61%, water flux 40 L / m 2h; width of the inhibition zone (none), bacterial growth under the sample (none), antibacterial effect (good); Example 2: Desalination rate 99.59%, water flux 46 L / m 2 h; width of the inhibition zone (none), bacterial growth under the sample (none), antibacterial effect (good); Comparative Example 1: Desalination rate 99.60%, water flux 41 L / m 2 h; width of the inhibition zone (none), bacterial growth under the sample (slight), and antibacterial effect (good); The results showed that the antibacterial coating had no adverse effect on the filtration performance of the membrane, but increased the antibacterial effect of the membrane, which can effectively prevent microbial contamination of the membrane during use. Adding surfactants to the water phase increased the flux of the membrane and further improved the antibacterial performance of the membrane.

[0033] The above are only specific implementation methods disclosed in this case, but the protection scope of the present disclosure is not limited thereto. The protection scope disclosed in this case should be based on the protection scope of the claims.

Claims

1. A method for preparing a reverse osmosis membrane resistant to microbial contamination, characterized in that: The following steps are involved: Step 1, immersing the surface of the base film in an aqueous solution containing a polyamine monomer so that the pores are filled with the aqueous solution; Step 2, after removing the excess aqueous solution, immersing the base film surface in an oil phase solution containing trimesoyl chloride; Step 3: After the reaction is completed, the membrane is placed in an oven for drying to remove the oil phase solvent; Step 4, immersing the membrane in citric acid solution, pure water, and glycerol aqueous solution in turn for cleaning, and drying again; Step 5: After immersing the membrane surface in the antibacterial coating solution, drying it, a reverse osmosis membrane resistant to microbial contamination is obtained.

2. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 1, characterized in that: The aqueous phase solution is prepared by adding polyamine monomers and surfactants into pure water and stirring until dissolved.

3. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 2, characterized in that: The polyamine monomer is m-phenylenediamine, and the concentration is 2-5%.

4. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 2, characterized in that: The surfactant is one of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate, and the concentration is 0.01-0.05%.

5. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 1, characterized in that: The oil phase solution is prepared by adding trimesoyl chloride to the oil phase solvent and stirring until dissolved; The concentration of trimesoyl chloride is 0.05-0.3%.

6. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 1, characterized in that: The concentration of the citric acid solution is 5-10%.

7. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 1, characterized in that: The concentration of the glycerol aqueous solution is 5-10%.

8. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 1, characterized in that: The preparation method of the antibacterial coating is: Add sodium dodecyl sulfate into pure water, stir until completely dissolved, then add mugwort extract and stir evenly, then add hydrochloric acid, glutaraldehyde and PVA solution in sequence and stir evenly.

9. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 1, characterized in that: The concentration of the wormwood extract is 0.5-1.5%.

10. The method for preparing a reverse osmosis membrane resistant to microbial contamination according to claim 1, characterized in that: The concentration of the sodium lauryl sulfate is 0.05-0.1%.