CN115770491A - High-flux composite membrane and preparation method thereof - Google Patents
High-flux composite membrane and preparation method thereof Download PDFInfo
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- CN115770491A CN115770491A CN202211614572.XA CN202211614572A CN115770491A CN 115770491 A CN115770491 A CN 115770491A CN 202211614572 A CN202211614572 A CN 202211614572A CN 115770491 A CN115770491 A CN 115770491A
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Abstract
The invention relates to a preparation method of a high-flux composite membrane, wherein the high-flux composite membrane comprises a bottom membrane and a polyamide functional separation layer carried by the bottom membrane, and the polyamide functional separation layer is prepared by adopting an interfacial polymerization reaction; the aqueous phase solution contains hydrophilic polyamine monomer, acid absorbent, more than two anionic surfactants with different molecular chain lengths and at least one positively charged water-soluble polymer; and carrying out interfacial polymerization reaction on the aqueous phase solution serving as a reactant and an oil phase solution in which a polybasic acyl chloride monomer is dissolved, and carrying out heat treatment after the reaction. The anionic surfactants with different molecular chain lengths can form nanoparticles after being coordinated with positively charged water-soluble polymers, and the nanoparticles are distributed at various positions of different depths in the polyamide functional separation layer and form continuous nanochannels, so that the water flux of the composite membrane is increased, and the desalting capacity of the polyamide functional separation layer is not influenced.
Description
Technical Field
The invention relates to the technical field of water treatment filter membranes, in particular to a high-flux composite membrane and a preparation method thereof.
Background
The flux of the composite membrane determines the working efficiency and energy consumption of the membrane, and the larger the flux is, the higher the working efficiency is and the lower the energy consumption is. However, the flux and the desalination rate of the composite membrane have a trade-off relationship, and increasing the flux and desalination rate of the composite membrane becomes a technical bottleneck in the water treatment industry, so that it is difficult to make the composite membrane have high retention rate while maintaining high flux.
The current methods for increasing the water flux of the reverse osmosis membrane comprise: in the preparation process of the composite membrane (prepared by interfacial polymerization), nano particles (such as zeolite, nano graphene oxide, nano silicon dioxide, nano titanium dioxide and the like) are added into a water phase or an oil phase; adding a hydrophilic substance to the aqueous phase; adding an ester plasticizer into the oil phase; after the preparation of the composite membrane is finished, hydrophilic modification and the like are carried out on the membrane surface. However, among these throughput-improving methods, the method of adding nanoparticles is most applied, but is also most difficult to implement. The first reason is that the nanoparticles are difficult to disperse and easy to agglomerate; secondly, because the common nano particles without modification lack effective adhesion with the separation layer, the nano particles are likely to fall off or escape, thus endangering the safety of drinking water. The hydrophilic substance is coated on the surface of the composite membrane, and the hydrophilic substance is easy to fall off. The hydrophilic macromolecules added in the water phase are difficult to diffuse into the oil phase, and the improvement on the flux is not obvious. The addition of plasticizers, while increasing water flux, generally results in a decrease in salt rejection of the composite membrane.
Disclosure of Invention
Technical problem to be solved
In view of the above technical problems of the prior art, the present invention provides a method for preparing a high flux composite membrane, which can effectively improve the water flux of the composite membrane and maintain a high salt rejection rate by constructing continuous nanochannels formed by nanoparticles in a functional separation layer of the composite membrane.
(II) technical scheme
In order to achieve the purpose, the invention adopts the main technical scheme that:
in a first aspect, the present invention provides a method for preparing a high-throughput composite membrane, wherein the high-throughput composite membrane comprises a base membrane and a polyamide functional separation layer carried by the base membrane, and the polyamide functional separation layer is prepared by interfacial polymerization;
wherein the aqueous phase solution is prepared according to the following method: dispersing hydrophilic polyamine monomers, an acid absorbent, more than two anionic surfactants with different molecular chain lengths and at least one positively charged water-soluble polymer in water to prepare an aqueous phase solution;
the water phase solution is used as reactant to carry out interfacial polymerization reaction with oil phase solution dissolved with polybasic acyl chloride monomer, and heat treatment is carried out after the reaction.
According to the preferred embodiment of the invention, the preparation method comprises the following steps:
s1, dip-coating a water phase solution on the surface of a bottom film or coating the water phase solution on the bottom film, standing to enable the water phase solution to be adsorbed on the bottom film, and removing the residual water phase solution on the surface of the bottom film to obtain a dry film;
s2, coating the oil phase solution on the dry film, standing, removing the oil phase solution remained on the surface of the film, and putting the film into an oven for heat treatment to obtain the high-flux composite film.
According to a preferred embodiment of the invention, in the aqueous phase solution, the hydrophilic polyamine monomer is one or a mixture of more of piperazine, m-phenylenediamine, m-xylylenediamine, p-phenylenediamine, o-phenylenediamine, diaminotoluene and polyethyleneimine, and the mass concentration of the polyamine monomer is 0.05-5%; the acid absorbent is one or more of sodium carbonate, trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, sodium hydroxide, potassium hydroxide and triethylamine, and the mass concentration is 0.1-3%. The acid absorbent is mainly used for reacting with byproduct hydrochloric acid in the process of interfacial polymerization reaction, and neutralizing the hydrochloric acid to promote the forward reaction. The acid-absorbing agent is too little, the reaction promoting effect is not obvious, and too much causes protonation of polyamine groups, thus being not beneficial to the reaction.
According to a preferred embodiment of the present invention, the two or more anionic surfactants having different molecular chain lengths in the aqueous solution are a combination of any two or more of the following surfactants having different molecular chains: sodium dodecyl sulfate, sodium hexadecyl sulfonate, sodium hexadecyl benzene sulfonate, sodium octadecyl sulfate, sodium octadecyl sulfonate, sodium octadecyl benzene sulfonate, disodium fatty alcohol polyoxyethylene ether sulfosuccinate monoester, fatty alcohol polyoxyethylene ether sodium sulfate AES, triethanolamine dodecylbenzene sulfonate, sodium dodecylbenzene sulfonate, alpha-olefin sulfonate, sodium abietate, diisooctyl succinate sodium sulfonate and sodium camphor sulfonate.
According to a preferred embodiment of the present invention, the total concentration by mass of the two or more anionic surfactants having different molecular chain lengths in the aqueous solution is 0.5 to 5%, more preferably 0.6 to 1.5%; wherein, in the aqueous phase solution, the molecular chain length of the anionic surfactant is distributed in a step way. The step distribution specifically means that the molecular chain lengths are not concentrated on the same molecular chain length, but anionic surfactants with various molecular chain lengths are added into a water phase, and continuous gradation is formed by different molecular chain lengths.
According to a preferred embodiment of the present invention, in the aqueous phase solution, the positively charged water-soluble polymer is at least one of Cationic Polyacrylamide (CPAM), chitosan quaternary ammonium salt, poly (allylamine-hydrochloric acid) (PAH); the mass concentration of the compound in the aqueous phase solution is 0.05-0.6%, and more preferably 0.1-0.35%.
According to a preferred embodiment of the present invention, the two or more anionic surfactants having different molecular chain lengths comprise anionic surfactants having different molecular chain lengths of 3 to 5; and the molecular chain length of the anionic surfactants is distributed in a step distribution.
According to the preferred embodiment of the invention, the polybasic acyl chloride monomer in the oil phase solution is one or more of trimesoyl chloride, isophthaloyl chloride, 3,3',5,5' -biphenyl tetracarboxyl chloride, terephthaloyl chloride and adipoyl chloride; the solvent of the oil phase solution is one or more of n-hexane, isoparaffin Isopar G and isoparaffin Isopar L; the mass concentration of the polyacyl chloride monomer in the oil phase solution is 0.01-2%. The mass concentration is preferably 0.2 to 0.3%. Preferably, the polybasic acid chloride monomer is trimesoyl chloride (TMC).
Preferably, the base membrane is one or more of a polysulfone base membrane, a polyether sulfone base membrane, a polyethylene base membrane, a polyimide base membrane, a polypropylene base membrane, a polyacrylonitrile base membrane, a polyvinylidene fluoride base membrane and a polyvinylidene fluoride base membrane. More preferably, the primary membrane is polysulfone primary membrane, and the polysulfone primary membrane comprises a base material such as non-woven fabric as a strength support and a polysulfone membrane covering the surface of the base material.
In the preparation process, the water phase solution is coated on a bottom membrane, the water phase solution is kept stand for 30-60s, the redundant water phase solution on the surface of the bottom membrane is removed, the membrane is dried, then the oil phase solution is coated, the redundant oil phase solution on the surface of the membrane is removed after the membrane is kept stand for 30-60s, and the membrane is placed in a forced air drying box at the temperature of 40-140 ℃ for treatment for 2-6min, so that the composite membrane with high flux and high desalination rate is prepared.
Preferably, the heat treatment comprises controlling the heating temperature using an oven, a forced air drying oven, a hot plate or a water bath, the heating temperature being 40-140 ℃. Preferably, the heat treatment temperature and time are controlled according to the chosen solvent of the oil phase solution: if the solvent of the oil phase solution is normal hexane (boiling point 69 ℃), the heat treatment temperature is in the range of 40-100 ℃, and the treatment time is about 2-6min; if IsoparG (initial boiling point 163 ℃), the heat treatment temperature is in the range of 60-120 ℃, and the treatment time is about 2-6min; if Isopar L (initial boiling point of 185 ℃), the heat treatment temperature ranges from 80 ℃ to 140 ℃, and the treatment time is about 2-6min; under the heat treatment condition, the prepared composite film has better performance.
In a second aspect, the present invention also provides a high-throughput composite membrane prepared by the method described in any of the above embodiments.
Based on the basic principle of the invention, the invention also provides a high-flux composite membrane, which comprises a bottom membrane and a polyamide functional separation layer covered on the surface of the bottom membrane; the polyamide functional separation layer contains nanoparticles, the depth of the nanoparticles in the polyamide functional separation layer is in gradient distribution, and the nanoparticles are formed by coordination of an anionic surfactant and a positively charged water-soluble polymer.
(III) advantageous effects
The invention mainly adds more than two anionic surfactants with different molecular chain lengths and at least one positively charged water-soluble polymer into an aqueous phase solution of polyamide interfacial polymerization reaction, wherein the anionic surfactants with different molecular chain lengths have different capacities of entering a polyamide functional separation layer, the deeper the molecular chain is, the shallower the depth the anionic surfactant with short molecular chain enters the polyamide functional separation layer, and because the anionic surfactants are coordinated with the positively charged water-soluble polymer, nanoparticles can be formed, and because the other end of the nanoparticles is connected with the hydrophobic end of the surfactants, in the interfacial polymerization reaction process, all the surfactants are arranged in a manner that the hydrophobic end faces upwards (enters an oil phase solution) and the nanoparticles are inserted into the interior of the polyamide functional separation layer downwards, and the nanoparticles can be conveyed to different positions in the polyamide functional separation layer by the surfactants with different molecular chain lengths. After the interfacial polymerization reaction is finished, the nano particles are remained at different depths of the polyamide functional separation layer, and the nano particles distributed at different depth positions form continuous nano channels, so that the water flux of the composite membrane is increased, and the desalting capability of the polyamide functional separation layer is not influenced.
Experiments prove that the performance of the composite membrane prepared by the invention is tested under the conditions that the test pressure is 1.55MPa, the concentrated water flow is 1.0GPM, the environmental temperature is 25 ℃, the pH value of the concentrated water is 6.5-7.5, and the concentrated water is 2000PPm sodium chloride, the rejection rate of the tested composite membrane to sodium chloride is 99.7% at most, and the water flux is 84LMH at most. Compared with the highest water flux 74LMH of CN113262643B and the highest water flux 68LMH of CN113262644B of the prior application of the applicant, the method has obvious improvement.
Drawings
Fig. 1 is a schematic structural diagram of a finished high-flux composite membrane product according to the present invention.
Detailed Description
For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.
Fig. 1 is a schematic structural diagram of a high-flux composite membrane according to the present invention, which includes a base membrane 1 and a polyamide functional separation layer 2 covering the surface of the base membrane. The polyamide functional separation layer 2 has a certain thickness, the polyamide functional separation layer 2 contains nano-particles 3, and the nano-particles 3 are distributed in a gradient manner in the polyamide functional separation layer. The nanoparticles 3 are formed by coordinating an anionic surfactant and a positively charged water-soluble polymer.
The continuous distribution of the nanoparticles at different depth positions in the polyamide functional separation layer is a key element for the implementation of the solution of the invention. Therefore, when the polyamide functional separation layer is prepared on the bottom film by using interfacial polymerization reaction, the prepared aqueous solution not only contains polyamine monomers (for participating in polymerization reaction), acid-absorbing agents (catalysis) and the like, but also simultaneously adds more than two types of anionic surfactants with different molecular chain lengths and positively charged water-soluble polymers for forming nanoparticles by coordination with the anionic surfactants. The negatively charged end of the anionic surfactant is combined with the positively charged water-soluble polymer by positive and negative electricity coordination to form nano particles; the positively charged water soluble polymer is not only positively charged, but also has good water solubility, and can be highly dispersed in an aqueous solution. After the oil phase solution is coated, the hydrophobic end of the anionic surfactant enters one side of the oil phase solution, so that the nanoparticles are retained inside the polyamide functional separation layer, and the depth positions of the nanoparticles in the polyamide functional separation layer are different due to different molecular chain lengths of the anionic surfactant. The polyamine monomer and the polyacyl chloride monomer are polymerized and simultaneously have random crossing and winding relation with the molecular chain of the anionic surfactant, so that the nano particles are firmly retained in the composite film and are not easy to fall off and escape, the composite film has good durability and can not pollute drinking water.
Example 1
The preparation method of the composite membrane of the embodiment is as follows:
(1) Preparing aqueous solution
Adding sodium dodecyl sulfate, sodium camphorsulfonate, chitosan quaternary ammonium salt and triethylamine into water, and uniformly mixing to obtain a water-phase solution for later use.
Wherein the mass fraction of the sodium dodecyl sulfate, the mass fraction of the sodium camphorsulfonate, the mass fraction of the chitosan quaternary ammonium salt, the mass fraction of the m-phenylenediamine and the mass fraction of the triethylamine in the aqueous phase solution are respectively 0.5%, 1% and 0.1%, respectively.
(2) Preparing oil phase solution
Preparing an oil phase solution of 0.25 mass percent of trimesoyl chloride (TMC), wherein the solvent is an isoparaffin solvent (Isopar L).
(3) Interfacial polymerization and heat treatment
Coating the water phase solution on a polysulfone basement membrane, standing for 60s, pouring off the redundant solution, and drying the membrane surface by cold air; and coating the oil phase solution on the blow-dried membrane, standing for 30s, pouring out the redundant oil phase solution, and directly placing the membrane into a 80 ℃ forced air drying oven for heat treatment for 2min to obtain the high-flux composite membrane.
Example 2
In this example, the composition of an aqueous solution was adjusted based on example 1, wherein the mass fraction of sodium lauryl sulfate was 0.3%, the mass fraction of sodium camphorsulfonate was 0.3%, the mass fraction of chitosan quaternary ammonium salt was 0.1%, the mass fraction of m-phenylenediamine was 1.0%, and the mass fraction of triethylamine was 0.2%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 3
In this example, the composition of an aqueous solution was adjusted based on example 1, wherein the mass fraction of sodium lauryl sulfate was 0.3%, the mass fraction of sodium hexadecylbenzene sulfonate was 0.3%, the mass fraction of sodium camphorsulfonate was 0.3%, the mass fraction of chitosan quaternary ammonium salt was 0.25%, the mass fraction of m-phenylenediamine was 1.0%, and the mass fraction of triethylamine was 0.2%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 4
In this example, the composition of an aqueous solution was adjusted based on example 1, wherein the mass fraction of sodium rosinate was 0.2%, the mass fraction of sodium lauryl sulfate was 0.2%, the mass fraction of sodium camphorsulfonate was 0.3%, the mass fraction of chitosan quaternary ammonium salt was 0.2%, the mass fraction of m-phenylenediamine was 1.0%, and the mass fraction of trisodium phosphate was 0.3%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 5
In this example, the composition of the aqueous solution was adjusted based on example 1, wherein the mass fraction of sodium rosinate was 0.4%, the mass fraction of sodium camphorsulfonate was 0.5%, the mass fraction of chitosan quaternary ammonium salt was 0.25%, the mass fraction of m-phenylenediamine was 1.0%, and the mass fraction of trisodium phosphate was 0.3%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 6
In this example, the composition of the aqueous solution was adjusted based on example 1, wherein the mass fraction of sodium rosinate was 0.4%, the mass fraction of sodium lauryl sulfate was 0.5%, the mass fraction of chitosan quaternary ammonium salt was 0.3%, the mass fraction of p-phenylenediamine was 1.0%, and the mass fraction of trisodium phosphate was 0.3%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 7
This example is based on example 1, wherein the composition of the aqueous solution is adjusted, wherein sodium alcohol ether sulphate AES (C) 14 H 29 O 5 NaS) 0.25 wt%, sodium diisooctyl succinate sulfonate (C) 20 H 37 NaO 7 S) 0.25% by mass, alpha-olefin sulfonate (RCH = CH (CH) 2 ) n -SO 3 Na, n = C14-16) mass fraction of 0.25%, CPAM mass fraction of 0.35%, p-phenylenediamine mass fraction of 1.0%, trisodium phosphate mass fraction of 0.3%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 8
In this example, the composition of an aqueous solution was adjusted based on example 1, wherein the mass fraction of sodium stearyl sulfate was 0.15%, and fatty alcohol-polyoxyethylene ether sulfosuccinic acid monoester disodium salt MES-30 (C) 22 H 40 Na 2 O 10 S) is 0.25 percent, the mass fraction of sodium camphorsulfonate is 0.25 percent, the mass fraction of CPAM is 0.35 percent, the mass fraction of p-phenylenediamine is 1.0 percent, and the mass fraction of trisodium phosphate is 0.3 percent. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 9
In this example, the composition of an aqueous solution was adjusted based on example 1, wherein the mass fraction of sodium stearyl sulfate was 0.2%, and fatty alcohol-polyoxyethylene ether sulfosuccinic acid monoester disodium salt MES-30 (C) 22 H 40 Na 2 O 10 S) 0.25 percent of mass fraction, 0.25 percent of sodium camphorsulfonate, 0.2 percent of sodium hexadecyl sulfate, 0.25 percent of chitosan quaternary ammonium salt, 1.0 percent of p-phenylenediamine and 0.3 percent of trisodium phosphate. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Example 10
In this example, the composition of the oil phase solution was adjusted based on example 9, and an Isopar G solvent was prepared in which isophthaloyl dichloride was present in an amount of 0.30% by mass. The composition of the aqueous solution and the reaction procedure are as in example 9, and finally a composite membrane is obtained.
Example 11
In this example, the composition of the oil phase solution was adjusted based on example 9, and the oil phase solution of 3,3',5,5' -biphenyltetracarboxylchloride was prepared in a mass fraction of 0.20%, and the solvent was isoparaffin solvent (Isopar L). The composition of the aqueous solution and the reaction procedure are as in example 9, and finally a composite membrane is obtained.
Comparative example 1
In the comparative example, on the basis of example 1, the composition of the aqueous phase solution was changed, the anionic surfactant camphor sodium sulfonate was removed, and only the surfactant sodium lauryl sulfate was contained, the mass fraction of which was 1.5%, the aqueous phase solution also contained 0.1% of chitosan quaternary ammonium salt, 1.0% of m-phenylenediamine, and 0.2% of triethylamine. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Comparative example 2
In the comparative example, on the basis of example 1, the composition of an aqueous phase solution was changed, all anionic surfactants were removed, and the aqueous phase solution contained only chitosan quaternary ammonium salt in a mass fraction of 0.1%, m-phenylenediamine in a mass fraction of 1.0%, and triethylamine in a mass fraction of 0.2%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
Comparative example 3
In the comparative example, on the basis of example 1, the composition of an aqueous phase solution was changed, and a chitosan quaternary ammonium salt was removed, and the aqueous phase solution contained only sodium lauryl sulfate in a mass fraction of 0.5%, sodium camphorsulfonate in a mass fraction of 1%, m-phenylenediamine in a mass fraction of 1.0%, and triethylamine in a mass fraction of 0.2%. The composition and reaction process of the oil phase solution are shown in example 1, and finally the composite membrane is prepared.
The composite membranes of examples 1 to 11 and comparative examples 1 to 3 were subjected to water flux and desalting performance tests under the following conditions: the testing pressure is 1.55MPa, the flow of concentrated water is 1.0GPM, the testing environment temperature is 25 ℃, the pH value of the concentrated water is 6.5-7.5, and the concentrated water is 2000PPm sodium chloride.
The test results are given in the following table:
from the test results, the performance test is carried out under the conditions that the test pressure is 1.55MPa, the concentrated water flow is 1.0GPM, the environmental temperature is 25 ℃, the pH value of the concentrated water is 6.5-7.5, and the concentrated water is 2000PPm sodium chloride, the rejection rate of the tested composite membrane to sodium chloride is 99.7% at most, and the water flux is 84LMH at most. Compared with the highest water flux 74LMH of CN113262643B and the highest water flux 68LMH of CN113262644B of the prior application of the applicant, the method has obvious improvement. Compared with examples 1-11, the water flux of the composite membrane is greatly reduced in the comparative example when only one anionic surfactant is retained in the aqueous phase solution or the positively charged water-soluble polymer is not added.
Comparing examples 1, 2 and 5 to 6, it is understood that when the mass concentration of the positively charged water-soluble polymer in the aqueous solution is equal and the types of the anionic surfactants having different molecular chain lengths are the same, the higher the mass concentration of the anionic surfactant is, the higher the water flux of the composite membrane to be produced is. However, the mass concentration of the anionic surfactant is too high, which is not beneficial to further improving the water flux and causes reagent waste. Comparing examples 9 to 11 with examples 3 and 5 to 6, it is understood that when the mass concentration of the anionic surfactant in the aqueous solution and the mass concentration of the positively charged water-soluble polymer are comparable, the larger the molecular chain length level of the anionic surfactant, the larger the water flux of the composite membrane obtained.
Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and these modifications or substitutions do not depart from the spirit of the corresponding technical solutions of the embodiments of the present invention.
Claims (10)
1. The preparation method of the high-flux composite membrane is characterized in that the high-flux composite membrane comprises a bottom membrane and a polyamide functional separation layer carried by the bottom membrane, wherein the polyamide functional separation layer is prepared by adopting an interfacial polymerization reaction;
wherein the aqueous phase solution is prepared according to the following method: dispersing hydrophilic polyamine monomers, an acid absorbent, more than two anionic surfactants with different molecular chain lengths and at least one positively charged water-soluble polymer in water to prepare an aqueous phase solution;
the water phase solution is used as reactant to carry out interfacial polymerization reaction with oil phase solution dissolved with polybasic acyl chloride monomer, and heat treatment is carried out after the reaction.
2. The method of claim 1, wherein the method comprises:
s1, dip-coating a water phase solution on the surface of a bottom film or coating the water phase solution on the bottom film, standing to enable the water phase solution to be adsorbed on the bottom film, and removing the residual water phase solution on the surface of the bottom film to obtain a dry film;
s2, coating the oil phase solution on the dry film, standing, removing the oil phase solution remained on the surface of the film, and putting the film into an oven for heat treatment to obtain the high-flux composite film.
3. The preparation method according to claim 1, wherein in the aqueous phase solution, the hydrophilic polyamine monomer is one or a mixture of more of piperazine, m-phenylenediamine, m-xylylenediamine, p-phenylenediamine, o-phenylenediamine, diaminotoluene and polyethyleneimine, and the mass concentration of the polyamine monomer is 0.05-5%; the acid absorbent is one or more of sodium carbonate, trisodium phosphate, disodium hydrogen phosphate, sodium dihydrogen phosphate, potassium phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, sodium hydroxide, potassium hydroxide and triethylamine, and the mass concentration is 0.1-3%.
4. The production method according to any one of claims 1 to 3, wherein the two or more anionic surfactants having different molecular chain lengths in the aqueous solution are a combination of any two or more of the following surfactants having different molecular chains: sodium dodecyl sulfate, sodium hexadecyl sulfonate, sodium hexadecyl benzene sulfonate, sodium octadecyl sulfate, sodium octadecyl sulfonate, sodium octadecyl benzene sulfonate, disodium fatty alcohol polyoxyethylene ether sulfosuccinate monoester, fatty alcohol polyoxyethylene ether sodium sulfate AES, triethanolamine dodecylbenzene sulfonate, sodium dodecylbenzene sulfonate, alpha-olefin sulfonate, sodium abietate, diisooctyl succinate sodium sulfonate and sodium camphor sulfonate.
5. The method according to claim 4, wherein the total concentration by mass of the two or more anionic surfactants having different molecular chain lengths in the aqueous solution is 0.5 to 5%.
6. The method according to claim 4, wherein the water-soluble positively-charged polymer in the aqueous solution is at least one of cationic polyacrylamide, quaternary ammonium salt of chitosan, and poly (allylamine-hydrochloric acid); the mass concentration of the water phase solution is 0.05-0.6%.
7. The method according to claim 5, wherein the two or more anionic surfactants having different molecular chain lengths comprise anionic surfactants having different molecular chain lengths of 3 to 5; and the molecular chain length of the anionic surfactants is distributed in a step distribution.
8. The preparation method according to claim 1, wherein the polybasic acid chloride monomer in the oil phase solution is one or more of trimesoyl chloride, isophthaloyl chloride, 3,3',5,5' -biphenyltetracarboxyl chloride, terephthaloyl chloride and adipoyl chloride; the solvent of the oil phase solution is one or more of n-hexane, isoparaffin Isopar G and isoparaffin Isopar L; the mass concentration of the polyacyl chloride monomer in the oil phase solution is 0.01-2%;
the basement membrane is one or more of a polysulfone basement membrane, a polyether sulfone basement membrane, a polyethylene basement membrane, a polyimide basement membrane, a polypropylene basement membrane, a polyacrylonitrile basement membrane, a polyvinylidene fluoride basement membrane and a polyvinylidene fluoride basement membrane.
9. A high-flux composite membrane, which is produced by the production method according to any one of claims 1 to 8.
10. A high flux composite membrane is characterized by comprising a bottom membrane and a polyamide functional separation layer covered on the surface of the bottom membrane; the polyamide functional separation layer contains nanoparticles, the depth of the nanoparticles in the polyamide functional separation layer is in gradient distribution, and the nanoparticles are formed by coordination of an anionic surfactant and a positively charged water-soluble polymer.
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