CN112999875A - Preparation method of organic ultrafiltration membrane - Google Patents
Preparation method of organic ultrafiltration membrane Download PDFInfo
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- CN112999875A CN112999875A CN202110366400.4A CN202110366400A CN112999875A CN 112999875 A CN112999875 A CN 112999875A CN 202110366400 A CN202110366400 A CN 202110366400A CN 112999875 A CN112999875 A CN 112999875A
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- B01D61/14—Ultrafiltration; Microfiltration
- B01D61/145—Ultrafiltration
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- B01D67/0002—Organic membrane manufacture
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- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/444—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by ultrafiltration or microfiltration
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Abstract
The invention discloses a preparation method of an organic ultrafiltration membrane, belonging to the technical field of water treatment organic membranes, and the preparation method of the organic ultrafiltration membrane comprises the following steps: s1: preparation of a base film, S2: implanting tree-shaped polyester, implanting the root of the tree-shaped polyester into a membrane hole of the organic base membrane after ultrasonic oscillation, covering the part containing functional groups on the surface of the tree-shaped polyester on the surface of the organic base membrane to form a polyester layer, S3: and (3) post-treatment, namely spraying a cross-linking agent mixed with a diluent on the surface of the dendritic polyester functional group, carrying out cross-linking reaction on the dendritic polyester functional group and the cross-linking agent under the heating condition to form a separation layer, and airing to obtain the hydrophilic anti-pollution organic ultrafiltration membrane. The organic membrane prepared by the preparation method of the organic ultrafiltration membrane has good separation effect, stable flux and high rejection rate, and can be preserved in a dry state.
Description
Technical Field
The invention belongs to the technical field of water treatment organic membranes, and particularly relates to a preparation method of an organic ultrafiltration membrane.
Background
Membrane separation technology has been widely used in water treatment fields, in which ultrafiltration membranes play an important role in water treatment due to their high separation efficiency and simple and convenient process. The ultrafiltration membrane can not only completely remove macroscopic pollutants (such as silt, rust and the like) in water, but also remove most of macroscopic pollutants (such as bacteria, viruses, organic matters and the like) in water, so that the ultrafiltration membrane is widely applied to the fields of city and rural waterworks transformation, sewage treatment in public places and living communities, pretreatment of seawater desalination and the like.
The ultrafiltration membrane can be divided into an organic membrane and an inorganic membrane according to different membrane materials, and the organic membrane material has the advantages of low price, easy obtainment, convenient processing, various types, excellent performance and the like, so the ultrafiltration membrane is widely applied to the research and development and production of various membrane products. The organic membrane material is mainly organic high molecular polymer, general high molecular membrane materials in the market comprise polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), Polysulfone (PSF), polyether sulfone (PES), polypropylene (PP), Polytetrafluoroethylene (PTFE) and the like, the process for preparing the ultrafiltration membrane by using the materials is simple, the cost is low, the membrane rejection rate is high, the separation effect is good, the ultrafiltration membrane is easy to maintain and clean, but the high molecular membrane materials are hydrophobic materials, the surface energy is low, the hydrophobicity of the membrane materials can not only cause the increase of the pressure difference of the membrane in the using process, the energy consumption in the membrane separation operation process is increased, the adsorption of pollutants on the surface of the membrane can also be caused, membrane pores are blocked, the membrane pollution is caused, the membrane can not run when the membrane pollution is serious, and in order to solve the problem, the hydrophilic anti-pollution modification is carried out on the ultrafiltration.
The tree-like branched molecules are highly branched three-dimensional macromolecules, starting from core molecules, the structure of the tree-like macromolecules is obtained by continuously repeating branched growth outwards, namely the core is divided into two branches after the core is grown to a certain length through the branches, the two branches are branched again and grow into four branches, the steps are repeated until the core is grown to be dense enough to grow into a tree cluster, each branched branch is added once, the generation number of the branched branch is 1, and the higher the generation number, the higher the branching degree. Compared with linear polymers, the polymer has a highly branched structure, has a large number of terminal functional groups, is convenient for chemical reaction, is not easy to entangle molecular chains, is convenient to disperse into single macromolecules, has a higher intramolecular cavity structure and lower melt or solution viscosity, and is convenient to regularly deposit on the surface and in pores of an object. The dendrimer is widely applied in various fields due to unique physicochemical characteristics and rich varieties, but is less applied in the field of membrane separation, because people often adopt a step-by-step repeated method to synthesize the dendrimer in order to obtain an accurate molecular structure in the past, the process is very complicated, so the cost is higher, and the dendrimer is only applied in the fields with high individual added values, such as ink dispersants, synthesized nano catalysts, drug carriers and the like. The hyperbranched polymer is between the dendritic macromolecule and the linear polymer, has a plurality of similarities with the dendritic macromolecule although not having the regular geometric configuration of the dendritic macromolecule, and has the advantages of no strict separation and purification in the preparation process, high yield and lower cost. In order to apply the excellent performance of the dendrimer to the field of membranes and improve the performance of the membranes, many people adopt the hyperbranched macromolecules with low cost to modify the membranes and membrane materials, which are similar to the structure of the dendrimer, and obtain good effect. Patent CN 103263858A discloses a method for preparing a cross-linked hyperbranched polymer composite nanofiltration membrane in a water phase by one-step method, wherein a hydrolyzed polyacrylonitrile ultrafiltration membrane is used as a base membrane, a cross-linked hyperbranched polymer is used as a separation layer, and the composite nanofiltration membrane is prepared by one-step reaction. Patent CN 104069749A discloses a hyperbranched polymer polyamide composite reverse osmosis membrane and a preparation method thereof, the composite reverse osmosis membrane is prepared by carrying out interfacial polymerization on a mixed solution of an amino-terminated hyperbranched polymer and linear polyamine and an aromatic acyl chloride organic solution on a porous supporting layer, and the composite reverse osmosis membrane has the advantages of large membrane flux, high desalination rate and excellent performance. The patent CN101954251A and the patent CN 101961612A respectively disclose a method for hydrophilic modification of a flat membrane and a hollow fiber membrane by hyperbranched polymers, the method firstly bonds maleic anhydride to the surfaces of the flat membrane and a master control fiber membrane in an ultraviolet irradiation mode, and then carries the hyperbranched polymers with hydroxyl or amino at the tail ends to the surfaces of the membranes through covalent bonds by esterification reaction, thereby effectively improving the hydrophilicity and the contamination resistance of the flat membrane and the hollow fiber membrane. Patent CN 103962011A discloses a method for improving the anti-pollution performance of a hydrophobic separation membrane by grafting hyperbranched PEG on the surface of the hydrophobic separation membrane, the method firstly places the hydrophobic separation membrane in a plasma processing device for plasma discharge processing, and then grafts the hyperbranched PEG on the surface, the method can reduce the contact angle of the PVDF membrane surface to below 70 degrees, and the anti-pollution performance of the membrane is obviously improved. Although the hyperbranched polymer can improve the performance of the separation membrane, the hyperbranched polymer does not have a perfect symmetrical structure like a dendrimer, and compared with the dendrimer, the hyperbranched polymer has a structural defect, so that the hyperbranched polymer can be applied to the field of membrane separation and cannot achieve the same effect as the dendrimer, for example: the hyperbranched polymer is adopted in the same method, and the flux loss is serious under the condition that the membrane is subjected to high-temperature treatment or is not dried by a protective solution, because the rigidity of the hyperbranched polymer is not as good as that of the near-spherical dendritic macromolecule, and the shrinkage of an organic polymer membrane material in a high-temperature or dry state cannot be inhibited.
With the continuous research on dendrimers (such as dupont, DSM, Perstorp, westernshir, new materials limited, etc.), various types of dendrimers are continuously synthesized, and can be classified into polyesters, polyethers, polyamides, etc. according to the reaction unit of the dendrimer; the dendritic branched molecules can be classified into hydroxyl-terminated groups, amino-terminated groups, carboxyl-terminated groups, and the like, depending on the reactive groups at the ends of the dendritic branched molecules. The synthesis process is more and more advanced, the synthesis efficiency is higher and higher, and the cost of the dendrimer is lower and lower. Therefore, the dendritic branched molecules are adopted to carry out hydrophilic anti-pollution modification on the water treatment ultrafiltration membrane, so that the performance of the membrane is further improved, and the method has important academic significance and important economic value.
Disclosure of Invention
The invention aims to provide a preparation method of an organic ultrafiltration membrane, which has the advantages of good separation effect, stable flux, no attenuation, dry-state preservation and high rejection rate.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a preparation method of an organic ultrafiltration membrane, which comprises the following steps: s1: preparing a base membrane, namely dissolving a high-molecular membrane material and a pore-forming agent in a solvent to prepare a membrane casting solution, and preparing the base membrane through solution phase conversion, wherein S2: implanting tree-shaped polyester, adding the tree-shaped polyester into water, preparing uniform emulsion after rapid stirring, immersing the base film prepared in the step S1 into the uniform emulsion, implanting the root of the tree-shaped polyester into a film hole of the base film after ultrasonic oscillation, covering the part containing functional groups on the surface of the tree-shaped polyester on the surface of the base film to form a polyester layer, S3: and (2) post-treatment, namely taking out the base membrane implanted with the dendritic polyester, removing redundant water, spraying a crosslinking agent mixed with a diluent on the surface of the dendritic polyester functional group, carrying out crosslinking reaction on the dendritic polyester functional group and the crosslinking agent under the heating condition to form a hydrophilic anti-pollution separation layer, finally cleaning the base membrane in water, and airing to obtain the hydrophilic anti-pollution organic ultrafiltration membrane.
Preferably, the dendritic polyester is dendritic hydroxyl-terminated polyester with an aliphatic main chain and hydroxyl at the tail end, and the generation number of the dendritic hydroxyl-terminated polyester is 2-4.
Preferably, the dendritic polyester content of the homogeneous emulsion is between 5% and 10%.
Preferably, the diluent is one of acetone, tetrahydrofuran and petroleum ether.
Preferably, the cross-linking agent is one of glutaraldehyde and diisocyanate;
when the cross-linking agent is glutaraldehyde, p-toluenesulfonic acid is used as a catalyst, and the content of the catalyst is 0.9-1.2% of that of glutaraldehyde.
Preferably, the amount of cross-linking agent is 5% to 10% by mass of the diluent.
Preferably, in step S3, the infrared lamp is irradiated and heated at 40-60 ℃ for 0.5-1 h.
Preferably, the polymer membrane material is one of polyvinylidene fluoride (PVDF), polyvinyl chloride (PVC), and polyether sulfone (PES).
Preferably, the pore-foaming agent is at least one of polyvinylpyrrolidone (PVP) and polyethylene glycol (PEG).
Preferably, the solvent is one of N, N-Dimethylformamide (DMF), N-Dimethylacetamide (DMAC), N-methylpyrrolidone (NMP).
Preferably, the ratio of the polymer membrane material to the pore-forming agent to the solvent is 20:5: 75.
Preferably, the frequency of ultrasonic oscillation is 80-120KHz, and the oscillation time is 5-10 min.
Preferably, in step S3, after the base film is taken out, excess moisture is blown off by cold air.
The invention has the beneficial effects that:
the tree-shaped polyester root is implanted into the interior of the membrane, the polyester is fixed like a tree-shaped polyester tree which is inserted into soil, micropores on the surface of the membrane are covered by a tree-shaped polyester hydrophilic surface, functional groups of the polyester hydrophilic surface are crosslinked together through a crosslinking agent to form a hydrophilic anti-pollution separation layer, the separation layer prevents pollutants in water from directly contacting with the surface of the membrane, the adsorption of the membrane material on the pollutants in water is blocked, the rejection rate of the membrane is improved, and therefore the separation membrane prepared by the method has good separation effect, stable flux and no attenuation, and can be stored in a dry state.
Drawings
FIG. 1 is a scanning electron micrograph of a PVDF-based film without dendritic polyester intercalation according to an embodiment of the present invention.
FIG. 2 is a scanning electron microscope image of an organic ultrafiltration membrane of which the base membrane is embedded in dendritic polyester and modified by crosslinking in an embodiment of the invention.
FIG. 3 is a schematic diagram of a modification of the present invention.
Detailed Description
The invention will now be further described with reference to the accompanying drawings and detailed description.
The first embodiment is as follows:
as shown in fig. 1 to fig. 3, the method for preparing an organic ultrafiltration membrane provided in this embodiment, which utilizes a dendritic polyester crosslinking reaction to perform hydrophilic modification on the organic ultrafiltration membrane, includes the following steps:
dissolving polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) in a DMF solvent to prepare a membrane casting solution, wherein the proportion of PVDF/PVP/DMF is 20/5/75, preparing an organic ultrafiltration basal membrane through solution phase conversion, and then putting the organic ultrafiltration basal membrane in clean water to soak the solvent completely for later use; adding hydroxyl-terminated dendritic polyester of generation 4 into water, rapidly stirring to prepare uniform emulsion with dendritic polyester content of 5%, immersing an organic ultrafiltration base membrane into the uniform emulsion, starting ultrasonic oscillation, wherein the oscillation evaluation rate is 80KHz, the oscillation time is 5min, implanting the root of the dendritic polyester into a membrane hole of the organic ultrafiltration base membrane after the ultrasonic oscillation, and covering the part containing functional groups on the surface of the dendritic polyester on the surface of the organic ultrafiltration base membrane to form a polyester layer; taking the organic ultrafiltration basal membrane implanted with the 4 th generation hydroxyl-terminated dendritic polyester out, blowing off redundant moisture by cold air, spraying a mixed solution of glutaraldehyde mixed with petroleum ether and p-toluenesulfonic acid (the mass ratio of the glutaraldehyde to the petroleum ether is 10%, and the mass of the p-toluenesulfonic acid is 1% of that of the glutaraldehyde) on the surface of a dendritic polyester layer functional group, heating the surface of the organic ultrafiltration basal membrane at 60 ℃ for 1 hour to react with a cross-linking agent aldehyde group (-CHO) to form a hydrophilic anti-pollution separation layer, finally cleaning the membrane in water, and naturally airing to obtain the organic ultrafiltration membrane.
The organic ultrafiltration membrane prepared in the first example was tested and had the following properties: initial pure water flux of 900L/m at 20 ℃ under pressure of 0.1MPa2h, the flux is still 900L/m after half an hour2h; the PEG retention rate for a molecular weight of 5 ten thousand Da is 52%, and the PEG retention rate for a molecular weight of 8 ten thousand Da is 75%; the retention of polyethylene glycol at a molecular weight of 10 ten thousand Da was 95%.
Example two:
the preparation method of the organic ultrafiltration membrane provided in the embodiment utilizes the dendritic polyester crosslinking reaction to perform hydrophilic modification on the organic ultrafiltration membrane, and comprises the following steps:
dissolving polyvinyl chloride (PVC) and polyvinylpyrrolidone (PVP) in a DMAC solvent to prepare a membrane casting solution, performing solution phase conversion on the PVC/PVP/DMAC (20/5/75) to prepare an organic ultrafiltration base membrane, and then putting the organic ultrafiltration base membrane into clean water to soak the solvent completely for later use; adding hydroxyl-terminated dendritic polyester of the 3 rd generation into water, rapidly stirring to prepare a uniform emulsion with dendritic polyester content of 8%, immersing an organic ultrafiltration basal membrane into the uniform emulsion, starting ultrasonic oscillation, wherein the oscillation evaluation rate is 100KHz, the oscillation time is 8min, implanting one end of the dendritic polyester into a membrane hole after the ultrasonic oscillation, and covering the part containing functional groups on the surface of the dendritic polyester on the surface of the organic ultrafiltration basal membrane to form a polyester layer; taking the organic ultrafiltration basal membrane implanted with the 3 rd generation hydroxyl-terminated dendritic polyester out of cold air to blow off redundant moisture, spraying a mixed solution of glutaraldehyde mixed with tetrahydrofuran and p-toluenesulfonic acid (the mass ratio of the glutaraldehyde to the tetrahydrofuran is 8%, and the mass of the p-toluenesulfonic acid is 1% of that of the glutaraldehyde) on the surface of a dendritic polyester layer functional group, heating the surface of the organic ultrafiltration basal membrane at 50 ℃ for 45 minutes to enable dendritic polyester hydroxyl (-OH) and cross-linking agent aldehyde group (-CHO) to react to form a hydrophilic anti-pollution separation layer, finally cleaning the membrane in water, and naturally airing to obtain the organic ultrafiltration membrane.
The organic ultrafiltration membrane prepared in example two was tested and had the following properties: initial pure water flux of 400L/m at 20 ℃ under pressure of 0.1MPa2h, the flux is still 400L/m after half an hour2h; the PEG retention rate for a molecular weight of 5 ten thousand Da is 82%, and the PEG retention rate for a molecular weight of 8 ten thousand Da is 95%; the retention of polyethylene glycol with a molecular weight of 10 ten thousand Da is 99%.
Example three:
in the preparation method of the organic ultrafiltration membrane provided in the embodiment, the organic ultrafiltration membrane is subjected to hydrophilic modification by using a dendritic polyester crosslinking reaction, and the preparation method comprises the following steps:
dissolving polyether sulfone (PES), polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) in an NMP solvent to prepare a membrane casting solution, carrying out solution phase conversion on PES/PVP/PEG/NMP of 20/2.5/2.5/75 to prepare an ultrafiltration base membrane, and then putting the ultrafiltration base membrane into clean water to soak the solvent completely for later use; adding hydroxyl-terminated dendritic polyester of generation 2 into water, rapidly stirring to prepare a uniform emulsion with dendritic polyester content of 10%, immersing an organic ultrafiltration basal membrane into the uniform emulsion, starting ultrasonic oscillation, wherein the oscillation evaluation rate is 120KHz, the oscillation time is 10min, implanting one end of the dendritic polyester into a membrane hole of the organic ultrafiltration basal membrane after the ultrasonic oscillation, and covering a part containing functional groups on the surface of the dendritic polyester on the surface of the organic ultrafiltration basal membrane to form a polyester layer; taking out cold air from the organic ultrafiltration base membrane implanted with the 2 nd generation hydroxyl-terminated dendritic polyester to blow off redundant moisture, then spraying a diisocyanate solution mixed with acetone (the mass ratio of diisocyanate to acetone is 5%) on the surface of a functional group of the dendritic polyester layer, heating the membrane surface of the organic ultrafiltration base membrane at 40 ℃ for 0.5 hour to enable dendritic polyester hydroxyl (-OH) to react with a cross-linking agent isocyanate (-NCO) to form a hydrophilic anti-pollution separation layer, finally cleaning the membrane in water, and naturally airing to obtain the organic ultrafiltration membrane.
The organic ultrafiltration membrane prepared in example three was tested and had the following properties: initial pure water flux of 400L/m at 20 ℃ under pressure of 0.1MPa2h, the flux is still 400L/m after half an hour2h; the PEG retention rate for a molecular weight of 5 ten thousand Da is 62%, and the PEG retention rate for a molecular weight of 8 ten thousand Da is 85%; the retention of polyethylene glycol at a molecular weight of 10 ten thousand Da was 96%.
Comparative example one:
the difference from the first embodiment is that the heating temperature in the first embodiment is reduced to 40 ℃, and the rest is the same.
The organic ultrafiltration membrane prepared according to the comparative example A is tested, and the performances are as follows: initial pure water flux of 800L/m at 20 ℃ under 0.1MPa2h, flux after half an hour is 400L/m2h, attenuation is half; the PEG retention rate for a molecular weight of 5 ten thousand Da is 12 percent, and the PEG retention rate for a molecular weight of 8 ten thousand Da is 25 percent; the polyethylene glycol retention for a molecular weight of 10 ten thousand Da was 36%. From the above results it should be observed that the temperature is too low, no crosslinking reaction occurs and the dendritic polyesterThe membrane is not completely fixed on the surface of the membrane, the rigidity of the membrane is not enough, mechanical deformation occurs in long-time pressure test, the flux is reduced, and in addition, because a hydrophilic anti-pollution separation layer is not formed by crosslinking reaction, the pore diameter of the membrane is not reduced, and the interception rate of PEG is not high.
Comparative example two:
the difference from example three is that the heating time in example three was extended to 1 hour, and the other steps were the same.
The organic ultrafiltration membrane prepared in the second comparative example is tested, and the performances are as follows: initial pure water flux of 80L/m at 20 ℃ under pressure of 0.1MPa2h, flux was 80L/m after half an hour2h; the PEG retention rate for a molecular weight of 5 ten thousand Da is 81%, and the PEG retention rate for a molecular weight of 8 ten thousand Da is 98%; the retention of polyethylene glycol with a molecular weight of 10 ten thousand Da is 99%. From the above results, it can be seen that the crosslinking reaction time is too long, the crosslinking reaction is excessive, the formed hydrophilic anti-fouling separation layer is too thick and dense, the PEG rejection rate of the membrane is high, but the flux is small.
The invention adopts hydroxyl-terminated dendritic polyester as a reaction body, after one end of the hydroxyl-terminated dendritic polyester is deeply inserted into a membrane hole to be fixed, glutaraldehyde or isocyanate is used as a cross-linking agent to carry out cross-linking reaction under certain conditions, and a hydroxyl hydrophilic layer is formed to cover the surface of the membrane. Wherein, hydroxyl (-OH) is fully distributed on the surface of the hydroxyl-terminated dendritic polyester, aldehyde groups (-CHO) are arranged at two ends of glutaraldehyde, isocyanate groups (-NCO) are arranged at two ends of diisocyanate, nucleophilic addition reaction is carried out on one aldehyde group (-CHO) and two hydroxyl groups (-OH) under the catalysis of acid to generate acetal or ketal, and nucleophilic addition reaction can be carried out on one isocyanate group (-NCO) and one hydroxyl group (-OH) without a catalyst to generate urethane. The invention adopts the dendrimer instead of the hyperbranched polymer, because the structure of the dendrimer is regular and the rigidity is good, the surface of the organic ultrafiltration membrane modified by the dendrimer has no molecular defect, and the flux can never be attenuated; polyester dendrimers are adopted because compared with polyethers and polyamides, polyesters have good acid and alkali resistance and hypochlorous acid oxidability (the membrane can be cleaned by acid and alkali and an oxidizing agent in the process of running the membrane), and have good compatibility with organic polymer membrane materials; hydroxyl-terminated dendritic polyester is adopted because hydroxyl is a hydrophilic group with better anti-pollution capability in the film and can generate crosslinking reaction with a crosslinking agent; hydroxyl-terminated dendritic polyester with generation number 2-4 is adopted because dendritic polyester with too high generation number is not easy to embed into the film, and dendritic polyester with too low generation number has too small volume and can permeate the film. The invention adopts acetone, tetrahydrofuran and petroleum ether as the diluents of the cross-linking agent, on one hand, the substances can not react with the cross-linking agent, and in addition, the substances can not damage the membrane when being sprayed on the surface of the membrane, and the diluents are easy to volatilize and are very beneficial to the drying process of the membrane.
The biggest technical difficulty of the invention is that the operation of ultrasonic oscillation is matched with the average aperture of the basal membrane and the algebra of the dendritic polyester, and one end of the dendritic polyester is ensured to be accurately implanted into a membrane hole, therefore, the formula and the process are required to be accurately controlled from the preparation of the basal membrane. The invention has the innovation point that the method for improving the performance of the water treatment organic ultrafiltration membrane can prepare the separation membrane which has good separation effect, stable and never-attenuated flux and can be stored in a dry state, and the method has simple operation and stable and reliable process and is suitable for industrial production.
The separation membrane prepared by the method is characterized in that the root of the tree-shaped polyester is implanted into the membrane, the polyester is fixed like branches penetrating into soil, micropores on the surface of the membrane are covered by the tree-shaped polyester hydrophilic surface, functional groups of the polyester hydrophilic surface are crosslinked together through a crosslinking agent to form a hydrophilic anti-pollution separation layer, the separation layer prevents pollutants in water from directly contacting with the surface of the membrane, the adsorption of the membrane material on the pollutants in water is blocked, and the rejection rate of the membrane is improved.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art; the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The preparation method of the organic ultrafiltration membrane is characterized by comprising the following steps of:
s1: preparing a base membrane, namely dissolving a high-molecular membrane material and a pore-forming agent in a solvent to prepare a membrane casting solution, and performing solution phase conversion to prepare the base membrane;
s2: implanting tree-shaped polyester, adding the tree-shaped polyester into water, preparing uniform emulsion after rapid stirring, immersing the base film prepared in the step S1 into the uniform emulsion, implanting the root of the tree-shaped polyester into a film hole of the base film after ultrasonic oscillation, and covering the part containing functional groups on the surface of the tree-shaped polyester on the surface of the base film to form a polyester layer;
s3: and (2) post-treatment, namely taking out the base membrane implanted with the dendritic polyester, removing redundant water, spraying a crosslinking agent mixed with a diluent on the surface of the dendritic polyester functional group, carrying out crosslinking reaction on the dendritic polyester functional group and the crosslinking agent under the heating condition to form a hydrophilic anti-pollution separation layer, finally cleaning the base membrane in water, and airing to obtain the hydrophilic anti-pollution organic ultrafiltration membrane.
2. The method for producing an organic ultrafiltration membrane according to claim 1,
the dendritic polyester is dendritic hydroxyl-terminated polyester with an aliphatic structure as a main chain and hydroxyl at the tail end, and the generation number of the dendritic polyester is 2-4.
3. The method for producing an organic ultrafiltration membrane according to claim 1,
the content of the dendritic polyester in the uniform emulsion is 5-10%.
4. The method for producing an organic ultrafiltration membrane according to claim 1,
the diluent is one of acetone, tetrahydrofuran and petroleum ether.
The cross-linking agent is one of glutaraldehyde and diisocyanate;
when the cross-linking agent is glutaraldehyde, p-toluenesulfonic acid is used as a catalyst, and the content of the catalyst is 0.9-1.2% of that of glutaraldehyde.
5. The method for producing an organic ultrafiltration membrane according to claim 1,
the dosage of the cross-linking agent is 5-10% of the mass of the diluent.
6. The method for producing an organic ultrafiltration membrane according to claim 1,
in the step S3, the heating temperature is 40-60 ℃, and the heating time is 0.5-1 h.
7. The method for producing an organic ultrafiltration membrane according to claim 1,
the polymer membrane material is one of polyvinylidene fluoride, polyvinyl chloride and polyether sulfone;
the pore-foaming agent is at least one of polyvinylpyrrolidone and polyethylene glycol;
the solvent is one of N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.
8. The method for producing an organic ultrafiltration membrane according to claim 1,
the ratio of the polymer membrane material to the pore-forming agent to the solvent is 20:5: 75.
9. The method for producing an organic ultrafiltration membrane according to claim 1,
in the step S2, the frequency of the ultrasonic oscillation is 80-120KHz, and the oscillation time is 5-10 min.
10. The method for producing an organic ultrafiltration membrane according to claim 1,
in step S3, after the base film is taken out, excess moisture is blown off by cold air.
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| CN113663539A (en) * | 2021-09-16 | 2021-11-19 | 西安热工研究院有限公司 | Hyperbranched antibacterial polyurethane reverse osmosis membrane and preparation method thereof |
| CN113694731A (en) * | 2021-08-24 | 2021-11-26 | 江苏沛尔膜业股份有限公司 | Negatively charged ultrafiltration membrane for resisting microbial pollution and preparation method thereof |
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| CN112473400A (en) * | 2020-12-17 | 2021-03-12 | 盐城海普润科技股份有限公司 | Graphene micro-ultrafiltration membrane and preparation method thereof |
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| JPS6443309A (en) * | 1987-08-12 | 1989-02-15 | Tosoh Corp | Hydrophilic ultrafiltration membrane and manufacture thereof |
| CN1636623A (en) * | 2004-12-16 | 2005-07-13 | 李连超 | Nanofiltration film and its preparation process |
| CN1799682A (en) * | 2005-09-13 | 2006-07-12 | 浙江大学 | Method for improving hydrophilicity of polymer porous membrane by dentritic branching molecule |
| CN110314562A (en) * | 2019-07-01 | 2019-10-11 | 中国石油大学(华东) | Modified seperation film of branching molecule and preparation method thereof, composite separating film and application |
| CN112473400A (en) * | 2020-12-17 | 2021-03-12 | 盐城海普润科技股份有限公司 | Graphene micro-ultrafiltration membrane and preparation method thereof |
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| CN113694731A (en) * | 2021-08-24 | 2021-11-26 | 江苏沛尔膜业股份有限公司 | Negatively charged ultrafiltration membrane for resisting microbial pollution and preparation method thereof |
| CN113694731B (en) * | 2021-08-24 | 2023-06-23 | 江苏沛尔膜业股份有限公司 | Negatively charged ultrafiltration membrane for resisting microbial pollution and preparation method thereof |
| CN113663539A (en) * | 2021-09-16 | 2021-11-19 | 西安热工研究院有限公司 | Hyperbranched antibacterial polyurethane reverse osmosis membrane and preparation method thereof |
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