Preparation method of polyamide composite nanofiltration membrane with super-hydrophilic property
The polyamide composite nanofiltration membrane was prepared by interfacial polymerization and sodium p-aminobenzenesulfonic acid was used as an additive to solve the problems of wide pore size distribution and poor anti-fouling performance of the nanofiltration membrane, achieve high permeation flux and good separation selectivity, and extend the service life of the membrane.
Patent Information
- Application Number
- CN202511211244.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-28
- Publication Date
- 2025-10-17
AI Technical Summary
Existing industrial nanofiltration membrane materials have problems such as wide pore size distribution, low flux, and poor anti-pollution, resulting in low membrane selectivity and rapid flux decay, affecting service life and market application value.
The polyamide composite nanofiltration membrane was prepared by the traditional interfacial polymerization method. Sodium p-aminobenzenesulfonic acid was used as an aqueous phase additive, mixed with piperazine and dissolved in deionized water. Combined with the oil phase reaction solution of trimesoyl chloride, a polyamide composite nanofiltration membrane with super hydrophilic properties was formed through interfacial polymerization reaction.
It improves the hydrophilicity and separation selectivity of the membrane, increases the permeation flux and anti-fouling performance, and enhances the long-term operation stability and selectivity of the membrane.
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Figure CN120789923A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the field of nanofiltration membrane preparation methods, and particularly relates to a preparation method of a polyamide composite nanofiltration membrane with super-hydrophilic properties. BACKGROUND
[0002] As a major breakthrough in water treatment in the 21st century, the core value of nanofiltration membrane technology lies in realizing molecular-level precise separation (100-2000 Da molecular weight range), and the pore size distribution is between that of ultrafiltration membranes and reverse osmosis membranes, which can effectively block more than 98% of divalent ions (such as Ca 2+ , Mg 2+ ) and organic pollutants. In addition, its working pressure is only 1 / 3 of that of traditional reverse osmosis technology, which can greatly reduce the filtration energy consumption, and therefore has significant advantages in seawater desalination, food and pharmaceutical industries.
[0003] Although nanofiltration membranes have good monovalent and multivalent ion selectivity, the current nanofiltration membrane materials used in industry still have defects such as wide pore size distribution, low flux, poor anti-fouling property, which leads to low membrane selectivity, rapid flux decay and other performance problems, seriously affecting the service life of the membrane and failing to meet the actual application requirements. Therefore, how to improve the anti-fouling properties of the membrane, enhance the membrane permeation flux and enhance the membrane selectivity is the key to improving the market application value of nanofiltration membranes.
[0004] In recent years, a new thin film composite nanofiltration membrane has shown good hydrophilic properties and high permeation flux, and has stable divalent salt rejection performance. For example, a hydrophilic additive material is compounded into the selective layer of the nanofiltration membrane to improve its physical and chemical structure properties, thereby improving the comprehensive performance of the membrane. In the present application, sulfanilic acid sodium salt (Na-SAS) is a sulfonate salt, which is rich in hydrophilic functional groups such as amino and sulfonic acid groups, and has strong electronegativity. Therefore, according to this property, it can directly participate in the interfacial polymerization reaction and form a film, and is expected to improve the hydrophilic properties and separation performance of the membrane.
[0005] Based on the above analysis, the present application relates to a polyamide composite nanofiltration membrane with super-hydrophilic properties prepared by using a hydrophilic sulfonate salt as an aqueous phase additive, which can significantly improve the hydrophilic properties and charge properties of the membrane, and at the same time improve the permeation flux and separation selectivity of the membrane. The polyamide composite nanofiltration membrane is prepared by using a conventional interfacial polymerization method, which has the advantages of simple operation, firm and effective functional separation selection layer, good separation selectivity and anti-fouling performance, and is of great significance for improving the service life and market application value of the new polyamide nanofiltration membrane. SUMMARY
[0006] The present application is directed to the above technical analysis and the problems existing, provide a kind of preparation method of polyamide composite nanofiltration membrane with super hydrophilic characteristics, it is good, the good selectivity permeability and long-term operation stability is good.Firstly, a proper amount of sodium p-aminobenzenesulfonate (Na-SAS) is mixed with piperazine (PIP) powder to obtain an aqueous reaction solution, then trimesoyl chloride (TMC) is dispersed in n-hexane solution by ultrasonic to obtain an oil phase reaction solution.The base film is completely immersed in the aqueous reaction solution, and the aqueous reaction solution is completely wetted on the base film, after a period of time, the base film is taken out from the aqueous solution and naturally drained for standby, then the oil phase reaction solution is poured on the surface of the base film for interfacial polymerization reaction, after a period of time, the excess oil phase reaction solution is poured off and heat treated to ensure sufficient crosslinking, and the polyamide composite nanofiltration membrane is obtained.
[0007] To achieve the above technical solution: a kind of preparation method of polyamide composite nanofiltration membrane with super hydrophilic characteristics, comprising:
[0008] Step one, PIP monomer is weighed and placed in a conical flask, then deionized water is added and stirred with a glass rod to accelerate dissolution, to obtain an aqueous PIP monomer reaction solution, the mass concentration of PIP is 0.1-0.5%.
[0009] Step two, sodium p-aminobenzenesulfonate (Na-SAS) is weighed and added to the above aqueous reaction solution, and stirred to completely dissolve, to obtain a mixed aqueous reaction solution, the mass concentration of Na-SAS is 0%-1.0%.
[0010] Step three, an oil phase reaction solution is prepared, TMC is weighed and added to n-hexane solution and ultrasonically dispersed, wherein the mass fraction of TMC is 0.1%.In the embodiment of the present application, the mass fraction of TMC in the oil phase reaction solution is all 0.1%.
[0011] Step four, the polymer base film is immersed in the aqueous reaction solution to completely wet the base film, and the holding time is 5 min, and it is naturally drained.
[0012] Step five, the prepared TMC oil phase reaction solution is poured on the surface of the above base film, so that it is fully contacted and interfacial polymerization reaction is carried out, after a period of time, the residual oil phase reaction solution is poured off, to obtain a nascent polyamide composite nanofiltration membrane, the reaction time is 0.5-2.5 min.
[0013] Step six, the prepared composite nanofiltration membrane is placed in a constant temperature drying oven for heat treatment to ensure sufficient crosslinking, the heat treatment temperature is set to 65℃, and the heat treatment time is 15 min, to obtain a polyamide composite nanofiltration membrane.
[0014] Step nine, the prepared composite polyamide nanofiltration membrane is stored in deionized water for standby.
[0015] The polymeric base membrane material is preferably one of polyether sulfone (PES), polysulfone (PSF), and polyvinylidene fluoride (PVDF).
[0016] The present application has the following outstanding technical advantages.
[0017] In the present application, by preparing a mixed aqueous phase reaction solution including PIP and Na-SAS, in the process of interfacial polymerization reaction, the diffusion behavior of PIP monomers is optimized by using the non-covalent bond interaction between PIP and Na-SAS, including hydrogen bond, van der Waals force, etc., so as to optimize the interfacial polymerization reaction, and at the same time, the interface defects are reduced due to the direct participation of Na-SAS in the reaction. The prepared novel polyamide composite nanofiltration membrane has a relatively narrow pore size distribution, a relatively high charge density and super-hydrophilic properties, which ensures the ion separation selectivity, anti-fouling performance and long-term permeation flux stability of the polyamide composite nanofiltration membrane. The polyamide composite nanofiltration membrane has a relatively high sodium sulfate rejection rate (> 99%) and permeation flux (12-25 LMH / bar). BRIEF DESCRIPTION OF DRAWINGS
[0018] Figure 1 is the pore size distribution graph of part of the embodiments of the composite nanofiltration membrane of the present application.
[0019] Figure 2 is the water contact angle change graph of part of the embodiments of the composite nanofiltration membrane of the present application.
[0020] Figure 3 is the Zeta potential change graph of part of the embodiments of the composite nanofiltration membrane of the present application.
[0021] Figure 4 is the salt rejection performance and permeation performance change graph of part of the embodiments of the composite nanofiltration membrane of the present application.
[0022] Figure 5 is the separation selectivity graph of part of the embodiments of the composite nanofiltration membrane of the present application.
[0023] Figure 6 is the long-term operation stability graph of part of the embodiments of the composite nanofiltration membrane of the present application. DETAILED DESCRIPTION
[0024] The present application will be further described in detail below in combination with specific embodiments, it should be understood that the specific examples are only used to explain and introduce the present application, and cannot limit the application range of the present application, any modification and change made to the present application within the purpose and range of the present application falls within the protection scope of the present application.
[0025] Example 1:
[0026] The preparation method of the polyamide composite nanofiltration membrane with super-hydrophilic properties comprises the following steps:
[0027] Step one, weigh the PIP monomer and place it in a conical flask, then add deionized water and stir it with a glass rod to accelerate dissolution, to obtain a PIP monomer aqueous reaction solution, and the mass concentration of PIP is 0.1%.
[0028] Step two, weigh the Na-SAS and add it to the above aqueous reaction solution, stir to dissolve completely, to obtain a mixed aqueous reaction solution, and the mass concentration of Na-SAS is 0.8%.
[0029] Step three, prepare an oil phase reaction solution, weigh the TMC and add it to a n-hexane solution and perform ultrasonic dispersion, and the mass fraction of TMC is 0.1%.
[0030] Step four, immerse the polymer base film into the aqueous reaction solution, make it completely wet the base film, and keep for 5 minutes, and naturally drain.
[0031] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above base film, make it fully contact and perform interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, to obtain a nascent polyamide composite nanofiltration membrane, and the reaction time is 1 minute.
[0032] Step six, place the prepared composite nanofiltration membrane into a constant temperature drying oven for heat treatment, to fully crosslink, the heat treatment temperature is set to 65℃, and the heat treatment time is 15 minutes, to obtain a polyamide composite nanofiltration membrane.
[0033] Step seven, place the prepared composite polyamide nanofiltration membrane in deionized water for storage.
[0034] Example 2:
[0035] The preparation method of the polyamide composite nanofiltration membrane with super-hydrophilic properties comprises the following steps:
[0036] Step one, weigh the PIP monomer and place it in a conical flask, then add deionized water and stir it with a glass rod to accelerate dissolution, to obtain a PIP monomer aqueous reaction solution, and the mass concentration of PIP is 0.3%.
[0037] Step two, weigh the Na-SAS and add it to the above aqueous reaction solution, stir to dissolve completely, to obtain a mixed aqueous reaction solution, and the mass concentration of Na-SAS is 0.8%.
[0038] Step three, configure the oil phase reaction solution, take TMC and add it to the n-hexane solution and perform ultrasonic dispersion, wherein the mass fraction of TMC is 0.1%. In the embodiment of the application, the mass fraction of TMC in the oil phase reaction solution is 0.1%.
[0039] Step four, immerse the polymer base film into the water phase reaction solution, make it completely wet the base film, the holding time is 5 min, and naturally drain.
[0040] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above-mentioned base film, make it fully contact and perform interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, and the nascent polyamide composite nanofiltration membrane is obtained, the reaction time is 1 min.
[0041] Step six, place the prepared composite nanofiltration membrane into a constant temperature drying oven for heat treatment, so as to fully crosslink, the heat treatment temperature is set to 65℃, the heat treatment time is 15 min, and the polyamide composite nanofiltration membrane is obtained.
[0042] Step seven, place the prepared composite polyamide nanofiltration membrane in deionized water for storage.
[0043] Example 3:
[0044] The polyamide composite nanofiltration membrane with superhydrophilic properties prepared by the method of the embodiment comprises:
[0045] Step one, take PIP monomers and place them in a conical flask, then add deionized water and use a glass rod to stir them to accelerate dissolution, and obtain a PIP monomer water phase reaction solution, the mass concentration of PIP is 0.5%.
[0046] Step two, take Na-SAS and add it to the above-mentioned water phase reaction solution, stir to make it completely dissolved, and obtain a mixed water phase reaction solution, the mass concentration of Na-SAS is 0.8%.
[0047] Step three, configure the oil phase reaction solution, take TMC and add it to the n-hexane solution and perform ultrasonic dispersion, wherein the mass fraction of TMC is 0.1%. In the embodiment of the application, the mass fraction of TMC in the oil phase reaction solution is 0.1%.
[0048] Step four, immerse the polymer base film into the water phase reaction solution, make it completely wet the base film, the holding time is 5 min, and naturally drain.
[0049] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above-mentioned base film, make it fully contact and carry out interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, and obtain the nascent polyamide composite nanofiltration membrane, the reaction time is 1 min.
[0050] Step six, place the above-prepared composite nanofiltration membrane into a constant-temperature drying oven for heat treatment, so as to fully crosslink, the heat treatment temperature is set to 65℃, the heat treatment time is 15 min, and the polyamide composite nanofiltration membrane is obtained.
[0051] Step seven, place the above-prepared composite polyamide nanofiltration membrane in deionized water for storage.
[0052] Example 4:
[0053] The polyamide composite nanofiltration membrane with super-hydrophilic property prepared by the method of the embodiment comprises the following steps:
[0054] Step one, weigh the PIP monomer and place it in a conical flask, then add deionized water and stir it with a glass rod to accelerate dissolution, to obtain a PIP aqueous phase reaction solution, the mass concentration of PIP is 0.2%.
[0055] Step two, weigh the sodium salt of p-aminobenzenesulfonic acid (Na-SAS) and add it to the above-mentioned aqueous phase reaction solution, stir to dissolve completely, and obtain a mixed aqueous phase reaction solution, the mass concentration of Na-SAS is 0%.
[0056] Step three, prepare an oil phase reaction solution, weigh TMC and add it to a n-hexane solution and perform ultrasonic dispersion, wherein the mass fraction of TMC is 0.1%. In the embodiment of the application, the mass fraction of TMC in the oil phase reaction solution is all 0.1%.
[0057] Step four, immerse the polymer base film into the aqueous phase reaction solution, make it fully wet the base film, and keep for 5 min, and then naturally drain.
[0058] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above-mentioned base film, make it fully contact and carry out interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, and obtain the nascent polyamide composite nanofiltration membrane, the reaction time is 1 min.
[0059] Step six, place the above-prepared composite nanofiltration membrane into a constant-temperature drying oven for heat treatment, so as to fully crosslink, the heat treatment temperature is set to 65℃, the heat treatment time is 15 min, and the polyamide composite nanofiltration membrane is obtained.
[0060] Step seven, place the above-prepared composite polyamide nanofiltration membrane in deionized water for storage.
[0061] Example 5:
[0062] A method for preparing a polyamide composite nanofiltration membrane having super-hydrophilic properties according to this embodiment includes:
[0063] Step 1: Weigh the PIP monomer and place it in a conical flask, then add deionized water and stir it with a glass rod to accelerate dissolution to obtain a PIP monomer aqueous phase reaction solution with a mass concentration of PIP of 0.2%.
[0064] Step 2: Weigh sodium p-aminobenzenesulfonic acid (Na-SAS) and add it to the above aqueous reaction solution, stirring to completely dissolve it, thereby obtaining a mixed aqueous reaction solution. The mass concentration of Na-SAS is 0.2%.
[0065] Step 3: Prepare an oil phase reaction solution, weigh TMC, add it to a n-hexane solution and ultrasonically disperse it, wherein the mass fraction of TMC is 0.1%. In the embodiment of the present invention, the mass fraction of TMC in the oil phase reaction solution is 0.1%.
[0066] Step 4: Immerse the polymer base membrane in the aqueous reaction solution to completely wet the base membrane, maintain the solution for 5 minutes, and drain naturally.
[0067] Step 5: Pour the prepared TMC oil phase reaction solution onto the surface of the above-mentioned base membrane to allow it to fully contact and undergo interfacial polymerization reaction. After a period of time, pour out the remaining oil phase reaction solution to obtain the primary polyamide composite nanofiltration membrane. The reaction time is 1 minute.
[0068] Step 6: Place the composite nanofiltration membrane prepared above into a constant temperature drying oven for heat treatment to fully cross-link. The heat treatment temperature is set to 65° C. and the heat treatment time is 15 minutes to obtain a polyamide composite nanofiltration membrane.
[0069] Step 7: Place the composite polyamide nanofiltration membrane prepared above in deionized water for storage.
[0070] Example 6:
[0071] A method for preparing a polyamide composite nanofiltration membrane having super-hydrophilic properties according to this embodiment includes:
[0072] Step 1: Weigh the PIP monomer and place it in a conical flask, then add deionized water and stir it with a glass rod to accelerate dissolution to obtain a PIP monomer aqueous phase reaction solution with a mass concentration of PIP of 0.2%.
[0073] Step 2: Weigh sodium p-aminobenzenesulfonic acid (Na-SAS) and add it to the above aqueous reaction solution, stirring to completely dissolve it, thereby obtaining a mixed aqueous reaction solution. The mass concentration of Na-SAS is 0.6%.
[0074] Step three, configure the oil phase reaction solution, weigh TMC and add it to the n-hexane solution and perform ultrasonic dispersion, wherein the mass fraction of TMC is 0.1%. In the embodiment of the application, the mass fraction of TMC in the oil phase reaction solution is 0.1%.
[0075] Step four, immerse the polymer base film into the water phase reaction solution, make it completely wet the base film, the holding time is 5 min, and naturally drain.
[0076] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above-mentioned base film, make it fully contact and perform interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, and the nascent polyamide composite nanofiltration membrane is obtained, the reaction time is 1 min.
[0077] Step six, place the prepared composite nanofiltration membrane into a constant temperature drying oven for heat treatment, so as to fully crosslink, the heat treatment temperature is set to 65℃, the heat treatment time is 15 min, and the polyamide composite nanofiltration membrane is obtained.
[0078] Step seven, place the prepared composite polyamide nanofiltration membrane in deionized water for storage.
[0079] Example 7:
[0080] The polyamide composite nanofiltration membrane with superhydrophilic property prepared by the method of the embodiment comprises:
[0081] Step one, weigh PIP monomers and place them in a conical flask, then add deionized water and use a glass rod to stir them to accelerate dissolution, and obtain a PIP monomer water phase reaction solution, the mass concentration of PIP is 0.2%.
[0082] Step two, weigh Na-SAS and add it to the above-mentioned water phase reaction solution, stir to make it completely dissolved, and obtain a mixed water phase reaction solution, the mass concentration of Na-SAS is 1%.
[0083] Step three, configure the oil phase reaction solution, weigh TMC and add it to the n-hexane solution and perform ultrasonic dispersion, wherein the mass fraction of TMC is 0.1%. In the embodiment of the application, the mass fraction of TMC in the oil phase reaction solution is 0.1%.
[0084] Step four, immerse the polymer base film into the water phase reaction solution, make it completely wet the base film, the holding time is 5 min, and naturally drain.
[0085] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above-mentioned base film, make it fully contact and carry out interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, and obtain the nascent polyamide composite nanofiltration membrane, the reaction time is 1 min.
[0086] Step six, place the above-prepared composite nanofiltration membrane into a constant-temperature drying oven for heat treatment, so as to fully crosslink, the heat treatment temperature is set to 65℃, and the heat treatment time is 15 min, and the polyamide composite nanofiltration membrane is obtained.
[0087] Step seven, place the above-prepared composite polyamide nanofiltration membrane in deionized water for storage.
[0088] Example 8:
[0089] The polyamide composite nanofiltration membrane with super-hydrophilic property prepared by the method of the embodiment comprises the following steps:
[0090] Step one, weigh the PIP monomer and place it in a conical flask, then add deionized water and stir it with a glass rod to accelerate dissolution, to obtain a PIP aqueous phase reaction solution, and the mass concentration of PIP is 0.2%.
[0091] Step two, weigh the sodium salt of p-aminobenzenesulfonic acid (Na-SAS) and add it to the above-mentioned aqueous phase reaction solution, stir to dissolve completely, and obtain a mixed aqueous phase reaction solution, and the mass concentration of Na-SAS is 0.8%.
[0092] Step three, prepare an oil phase reaction solution, weigh TMC and add it to a n-hexane solution and perform ultrasonic dispersion, and the mass fraction of TMC is 0.1%. In the embodiment of the application, the mass fraction of TMC in the oil phase reaction solution is all 0.1%.
[0093] Step four, immerse the polymer base film into the aqueous phase reaction solution, make it fully wet the base film, and keep for 5 min, and then naturally drain.
[0094] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above-mentioned base film, make it fully contact and carry out interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, and obtain the nascent polyamide composite nanofiltration membrane, the reaction time is 0.5 min.
[0095] Step six, place the above-prepared composite nanofiltration membrane into a constant-temperature drying oven for heat treatment, so as to fully crosslink, the heat treatment temperature is set to 65℃, and the heat treatment time is 15 min, and the polyamide composite nanofiltration membrane is obtained.
[0096] Step seven, place the above-prepared composite polyamide nanofiltration membrane in deionized water for storage.
[0097] Example 9:
[0098] The polyamide composite nanofiltration membrane with super-hydrophilic properties is prepared by the method comprising the following steps:
[0099] Step one, PIP monomers are weighed and placed in a conical flask, then deionized water is added and stirred with a glass rod to accelerate dissolution, obtaining a PIP monomer aqueous reaction solution, and the mass concentration of PIP is 0.2%.
[0100] Step two, sodium p-aminobenzenesulfonate (Na-SAS) is weighed and added to the above aqueous reaction solution, and stirred until it is completely dissolved, obtaining a mixed aqueous reaction solution, and the mass concentration of Na-SAS is 0.8%.
[0101] Step three, an oil phase reaction solution is configured, TMC is weighed and added to a n-hexane solution and ultrasonically dispersed, and the mass fraction of TMC is 0.1%. In the embodiment of the present application, the mass fraction of TMC in the oil phase reaction solution is all 0.1%.
[0102] Step four, the polymer base film is immersed in the aqueous reaction solution, the base film is completely wetted, the holding time is 5 min, and the base film is naturally drained.
[0103] Step five, the configured TMC oil phase reaction solution is poured on the surface of the above base film, so that it is fully contacted and subjected to interfacial polymerization reaction, after a period of time, the residual oil phase reaction solution is poured off, obtaining a nascent polyamide composite nanofiltration membrane, and the reaction time is 1.5 min.
[0104] Step six, the prepared composite nanofiltration membrane is placed in a constant temperature drying oven for heat treatment to fully crosslink, the heat treatment temperature is set to 65℃, the heat treatment time is 15 min, and a polyamide composite nanofiltration membrane is obtained.
[0105] Step seven, the prepared composite polyamide nanofiltration membrane is placed in deionized water for storage.
[0106] Example 10:
[0107] The polyamide composite nanofiltration membrane with super-hydrophilic properties is prepared by the method comprising the following steps:
[0108] Step one, PIP monomers are weighed and placed in a conical flask, then deionized water is added and stirred with a glass rod to accelerate dissolution, obtaining a PIP monomer aqueous reaction solution, and the mass concentration of PIP is 0.2%.
[0109] Step two, sodium p-aminobenzenesulfonate (Na-SAS) is weighed and added to the above aqueous reaction solution, and stirred until it is completely dissolved, obtaining a mixed aqueous reaction solution, and the mass concentration of Na-SAS is 0.8%.
[0110] Step three, configure the oil phase reaction solution, weigh the TMC and add it to the n-hexane solution and ultrasonic dispersion, wherein the mass fraction of TMC is 0.1%. In the embodiment of the application, the mass fraction of TMC in the oil phase reaction solution is 0.1%.
[0111] Step four, immerse the polymer base film into the water phase reaction solution, make it completely wet the base film, the holding time is 5 min, and naturally drain.
[0112] Step five, pour the prepared TMC oil phase reaction solution on the surface of the above-mentioned base film, make it fully contact and carry out the interfacial polymerization reaction, after a period of time, pour away the residual oil phase reaction solution, and the nascent polyamide composite nanofiltration membrane is obtained, the reaction time is 2.5 min.
[0113] Step six, place the above-prepared composite nanofiltration membrane into a constant temperature drying oven for heat treatment, so as to fully crosslink, the heat treatment temperature is set to 65℃, the heat treatment time is 15 min, and the polyamide composite nanofiltration membrane is obtained.
[0114] Step seven, place the above-prepared composite polyamide nanofiltration membrane in deionized water for storage.
Claims
1. A method for preparing a polyamide composite nanofiltration membrane with super hydrophilic properties, characterized in that Functional layer: The method comprises the following steps: weighing piperazine powder and placing it in a conical flask, adding deionized water to dissolve the mixture, obtaining an aqueous reaction solution containing piperazine monomer, then weighing sodium p-aminobenzenesulfonate powder and dissolving it in the piperazine solution to obtain a mixed aqueous reaction solution for standby use; weighing trimesoyl chloride and dispersing it in an n-hexane solution to obtain an oily reaction solution, wherein the mass concentration of trimesoyl chloride is 0.1%; firstly immersing a polymer base membrane in the mixed aqueous reaction solution for 5 minutes and then draining the solution; continuously pouring the oily reaction solution onto the surface of the base membrane to react, and after the reaction is completed, placing the base membrane in an oven for heat treatment to obtain a polyamide composite nanofiltration membrane, wherein the oven temperature is set to 65° C. and the heat treatment time is 15 minutes.
2. The method for preparing a polyamide composite nanofiltration membrane having super-hydrophilic properties according to claim 1, characterized in that The mass concentration of piperazine in the mixed aqueous phase reaction solution is 0.1-0.5%.
3. The method for preparing a polyamide composite nanofiltration membrane having super-hydrophilic properties according to claim 1, characterized in that The mass concentration of sodium p-aminobenzenesulfonate in the mixed aqueous phase reaction solution is 0-1.0%.
4. The method for preparing a polyamide composite nanofiltration membrane having super-hydrophilic properties according to claim 1, characterized in that The interfacial polymerization reaction time is 0.5 to 2.5 minutes.
5. The method for preparing a polyamide composite nanofiltration membrane having super-hydrophilic properties according to claim 1, characterized in that The base membrane is made of polyethersulfone.
6. The method for preparing a polyamide composite nanofiltration membrane having super-hydrophilic properties according to claim 1, characterized in that The composite nanofiltration membrane is a flat membrane.