KR20050074167A - Producing method of the polyamide composite membrane having high performance and fouling resistence - Google Patents

Abstract

The present invention relates to a separation membrane having excellent separation performance, and improves separation performance by applying a secondary coating on the surface of the separation membrane. In the present invention, the secondary coating is to improve the separation performance by controlling the surface roughness and simultaneously changing the surface charge inherent by coating and covalently bonding a compound having a reactive functional group on the surface of the separator.

Description

Producing Method of the Polyamide Composite Membrane having high performance and fouling resistence

The present invention relates to a selective separator having a characteristic of excellent separation performance and a method of manufacturing the same.

In general, dissociated materials are separated from the solvent by membranes having selectivity such as microfiltration, ultrafiltration, and reverse osmosis membranes. Reverse osmosis membranes have been used to desalination with a large amount of water while removing salts such as brackish water and seawater, while relatively low salts such as industrial water, agricultural water, and household water. Semi-saline desalination using reverse osmosis membrane or desalination of seawater means that salt or ions in the aqueous solution cannot pass through the membrane when pressurized by the aqueous solution containing salt or ions, and the purified water passes through the membrane It means to be water. At this time, the pressure applied should be more than the osmotic pressure of the aqueous solution, the action is the reverse of the osmotic process, and the higher the concentration of the aqueous solution, the greater the osmotic pressure, the higher the pressure applied to the feed water.

Since water such as brackish water and seawater contain a large amount of salts, reverse osmosis membranes desalination of these solutions should be excellent in salt removal ability (for reference, more than 98% of salts should be removed to be used as general water). In addition, there is no problem that the process pressure should be lowered to improve the size of the pump which is inevitable to operate the high concentration of brine, the noise and the low energy efficiency.

As another condition that reverse osmosis membranes should have, conventional commercial reverse osmosis membranes have to filter out a large amount of salt, so the amount of purified water that passes through the reverse osmosis membrane is so small that its utilization is insignificant. Even at relatively low pressures, a large amount of purified water passes through the membrane, i.e., the characteristics of high permeate flow are indispensable.

Known immediately permeate flow rate is being required desalination conditions, 800psi In ^{10gallon / ft 2 day (gfd)} , brackish water desalination process, 15gallon / ft ^2day (gfd) at least under 225psi pressure, than the salt rejection according to the application In some cases, high flow rates are important, or vice versa.

The general type of reverse osmosis membrane consists of a porous support layer and a polyamide-based thin film on the support layer. Typical polyamide membranes can be obtained by interfacial polymerization of polyfunctional amines and polyfunctional acyl halides.

U.S. Patent 4,277,344, previously filed by Cadette, discloses aromatic polyamides obtained by interfacial polymerization of aromatic polyfunctional amines containing two primary amine substituents and aromatic acyl halides having three or more acyl halide functional groups. Techniques for thin films have been proposed. In this case, the reverse osmosis membrane is coated with methaphenylenediamine (m-phenylendiamine) on a microporous polysulfone support, followed by removal of the excess metaphenylenediamine solution, and then trimezoyl chloride dissolved in Freon (trichlorotrifluoroethane). It is prepared by reacting with (TMC), wherein the contact time of the interfacial polymerization is 10 seconds and the reaction takes place within 1 second. As such, various studies have been conducted on polyamide reverse osmosis composite membranes in order to provide excellent salt removal rate and high flow rate improved membranes. In addition, in the industry, efforts have been made to improve the chemical resistance of membranes. Most of the research has been based on the use of various additives in the solution used in interfacial polymerization.

As an example, Tomashke's U.S. Patent 4,872,984 (registered in October 1989) (a) consists of an aromatic polyamine reactant and a monomer of essentially monomers having at least two or more amine functional groups to form a liquid layer on the microporous support layer. Applying the microporous support as an aqueous solution containing an amine salt; (b) the amine reactive reactant has, on average, at least about 2.2 acyl halides per molecule of the reactant and consists essentially of a polyfunctional acyl halide or mixture thereof Contacting the liquid layer with an organic solvent solution of a phosphorus aromatic amine reactive reactant and (c) drying the product of step 2 at a temperature of 60 to 110 ° C. for 1 to 10 minutes to form the permeable osmotic membrane. The reverse osmosis membrane manufacturing method was proposed.

Patents that attempt to form a film by adding an additive to a solution used in interfacial polymerization include Chau, U.S. Patent 4,983,291, Hirose, U.S. Patent 5,576,057, 5,614,099, and Tran, U.S. Patent 4,830,885, Koo U.S. Patents 6,063,278 and 6,015,495.

As another example, according to US Patent No. 5,178,766 of Ikeda, in order to improve the separation performance of the reverse osmosis membrane, an attempt was made to covalently bond the quaternary amine to the surface of the polyamide thin film formed by interfacial polymerization. The upper amine has been shown to have an epoxy group, an aziridine group, an episulfide group, a halogenated alkyl group, an amino group, a carboxyl group, a halogenated carbonyl group, and a hydroxyl group as a reactor on its surface and reaction site.

As a result of the above-mentioned efforts, the reverse osmosis membrane of polyamide composite thin films having excellent separation performance and permeation performance and excellent chemical resistance is left, but the problem of membrane contamination remains as an unresolved problem. The permeate flow rate is lowered by adsorbing or adhering the substance or dissolved substance to the membrane surface, and is generally caused by the floating of the suspended substance in the solution filtered by the hydrophobic bond and the electrostatic force and the membrane surface. Such contamination of the membrane lowers the permeation performance of the membrane, and thus, in order to obtain a certain amount of permeate, the pressure must be frequently corrected or, in serious cases, frequent cleaning.

In an attempt to reduce membrane fouling, Hachisuka (US Pat. No. 6,177,011) shows that it is possible to increase fouling resistance by recoating electrostatically neutral and hydrophilic polymers such as polyvinyl alcohol on the polyamide composite thin film surface. Since the direction of the development of the conventional reverse osmosis membrane was focused mainly on the desalination process, the reverse osmosis membrane based on the above-described development technology has a weakness that does not meet the expectation in terms of separation performance for pharmaceuticals or ultrapure semiconductor manufacturing requiring high organic matter removal rate at low concentration. It's coming out.

The present invention aims to improve the separation performance by modifying the surface of the separator, and in particular, to prepare a separator having excellent separation performance and fouling resistance by performing a secondary coating on a selective separator such as a polyamide reverse osmosis composite membrane. It was created for the purpose.

According to the present invention, a polyamide thin film is formed on a porous support, and then a secondary coating layer is formed on the polyamide thin film to prepare a polyamide reverse osmosis composite membrane, wherein the secondary coating is a polyamide compound having at least one semi-functional group. The present invention relates to a polyamide reverse osmosis composite membrane prepared by coating on a thin film and then bonding.

 The secondary coating can be applied without being limited to the material properties and uses of the polyamide-based composite thin film through interfacial polymerization on the porous support, and also can be applied without limitation to the material and type of the porous support. The microporous support has a microporous structure, and in particular, should have a pore size through which permeate can be sufficiently transmitted, and have a pore size of 1 to 500 nm to serve as a support in forming a thin film. Pore diameters greater than 500 nm may be manifested as defects in the final composite film due to depressions in thin film formation. Polysulfones, polyisulfones, polyimides, polyamides, polyimides, polyacrylonitriles, polymethylmethacrylates, polyethylene, polypropylene and polyvinylidene are microporous supports that can be usefully used in the present invention. Various halogenated polymers such as fluoride can be used as the material.

In addition, the thickness of the porous support is not limited in the present invention, but is preferably in the range of about 25um to 125um (more preferably 40um to 75um).

The polyamide-based composite thin film used in the present invention is generally formed by interfacial polymerization using a material that reacts with a polyamine and a polyamine, wherein the polyamine is a material having 2 to 3 amine functional groups per monomer. Or secondary amines. As examples of polyamines, aromatic primary diamines are used as metaphenylenediamines, paraphenylenediamines and substituents. In another example, cycloaliphatic primary diamines such as aliphatic primary diamines and cyclohexene diamines, and cycloaliphases such as piperazine Patic secondary amines, aromatic secondary amines and the like are used, and other suitable materials can be found in the references of the present invention.

Although the present invention is not limited to the kind of polyamine, it is particularly preferable to apply it to a separator formed with a metaphenylenediamine which is an aromatic primary diamine or piperazine which is a cycloaliphatic secondary diamine as a polyamine. When piperazine is used as a polyamine, a polyamide composite membrane is formed in a nanofiltration range having a relatively larger pore size than a reverse osmosis membrane. Compared to reverse osmosis membranes, nanofiltration has a lower salt removal rate than monovalent ions, but it is effective for removing divalent ions and organic substances with molecular weight of 300 or more. Therefore, softening process and drinking water to remove hardness components such as calcium and magnesium When applied to, it is effectively used to remove humic acid, a precursor of carcinogens such as trihalomecene.

The polyamine aqueous solution is mainly used at a concentration of 0.1 to 20% by weight, more preferably 0.5 to 8% by weight polyamine aqueous solution. The pH of the polyamine aqueous solution has a range of 7 to 13, and can be adjusted by adding 0.001 to 5% by weight of acid and base. Examples of such acids and bases include hydroxides, carboxylates, carbonates, borates, phosphorates of alkyl metals, trialkylamines, and the like. In addition, a basic acid support for neutralizing acid (HCl) generated during interfacial polymerization may be added to the polyamine aqueous solution, and another additive may be used by adding a polar solvent, an amine salt, a poly tertiary amine, and the like.

Polyacyl halides, polysulfonyl halides, polyisocyanates, etc. may be used as the material that reacts with the polyamine. More preferably, aromatic polyacyl halides such as trimezoyl chloride (TMC) and isophthaloyl chloride (IPC) are used. do. The material which reacts with an amine is generally used by dissolving in an organic solvent which is not mixed with water at 0.005 to 5% by weight (more preferably 0.01 to 0.5% by weight). Examples of organic solvents include halogenated hydrocarbons such as freons, hexane, cyclohexane, heptane, alkanes having 8 to 12 carbon atoms, and environmental problems such as ozone destruction of freons and low boiling points. In view, ISOPAR (Exxon Corp.) which is a mixture of 8 to 12 alkane carbon atoms is preferably used.

A general manufacturing process of the reverse osmosis membrane to be applied in the present invention is to remove the excess polyamine solution on the surface of the porous support coated with a polyamine (polyfunctional amine) solution by rolling, sponge, air knife and a suitable method, and then react with the polyamine. The organic solvent containing was contacted for 5 seconds to 10 minutes (more preferably, 20 seconds to 4 minutes) by immersion or spraying. The membrane obtained in this manner is dried at 50 ° C. or less for about 1 minute, and then immersed in a basic aqueous solution such as 0.2% by weight sodium carbonate at a suitable water temperature of normal to 95 ° C. for 1 to 30 minutes and washed with distilled water to obtain a reverse osmosis membrane. Before washing the polyamide composite film formed through the above method, the polyamide thin film surface is coated with an appropriate amount of a secondary coating compound, wherein the compound used is at least one amine, hydroxy or epoxy functional group. It has a water-insoluble property by covalently bonding to an acyl halide functional group present in an unreacted state during the interfacial polymerization of the polyamide composite membrane. The formation of covalent bonds here is a very important part of the secondary coating, and if no covalent bonds are made, the actual separator results in the secondary coating layer being washed away from the separator surface during use.

The secondary coating compound used in the present invention has at least one reactor capable of forming covalent bonds with acyl halides, and at the same time has a functional group capable of controlling the charge on the surface. The surface charge control means that the polyamide composite film is changed by artificially coating the surface charges inherent in the manufacturing process. The secondary coating can be modified to neutralize the surface charges, negative charges, positive charges according to the functional group, and can also control the hydrophilicity, hydrophobicity of the surface. In addition, the surface roughness may be controlled by adjusting the coating amount of the secondary coating compound.

The functional group capable of forming a covalent bond with the acyl halide is amine, hydroxy, epoxy or the like. Examples of the group capable of controlling the surface charge include alkyl, benzene, ether, ester, amide, urea, urethane, hydroxy, siloxane, phosphoric, sulfonic, carboxyl and amine groups. Specific examples of functional groups that control surface charge include a) functional groups that neutralize surface charges are alkyl groups, benzene groups, hydroxy groups, and siloxane groups, and b) carboxyl groups and sulfone functional groups that can control surface charges to negative charges. C) an acid group, a phosphoric acid group, and c) a functional group capable of controlling the surface charge to a positive charge, and may be controlled using an amine group such as primary amine, secondary amine, tertiary amine, and quaternary amine.

Secondary coating compounds for neutralizing the surface charge used in the present invention include arylamine, aminoacetaldehyde dimethylacetal, 2-aminobenzimidazole, 2-aminobenzothiazole, 2-aminoheptane, 2-amino-2- Methyl-1,3-propanediol, 2-amino-2-methyl-1-propanol, 1-amino-2-propanol, 3-amino-1-propanol, aniline, 2-anilinoethanol, benzylamine, 2- (Benzylamino) ethanol, tert-butylamine, n-butylamine, N, O-dimethylhydroxylamine, dipropylamine, diethylamine, ethanolamine, ethylamine, 2- (ethylamino) ethanol, perferylamine , 4-hydroxy-3-methoxybenzylamine, 2- (4-hydroxyphenyl) ethylamine, 2- (3,4-dihydroxyphenyl) ethylamine, 1,1-iminodi-2-propanol , Isobutylamine, isopentylamine, isopropylamine, 2-methoxybenzylamine, 4-methoxybenzylamine, bis (2-methoxyethyl) amine, 2-methoxyethylamine, 2- (4-methoxy Oxyphenyl) ethylamine, Tylamine, (methylamino) acetaldehydedimethylacetal, 2- (methylamino) ethanol, 4-methylbenzylamine, N-methylbenzylamine, N-methylbutylamine, N-methylcyclohexylamine, D (-)- N-methylglucamine, N-methylhydroxylamine, O-methylhydroxylamine, n-pentylamine, propylamine, di-butylamine, secondary-butylamine, cyclohexylamine, cyclopentylamine, Cyclopropanemethylamine, cyclopropylamine, diarylamine, 1,4-diaminobutane, 1,2-diaminocyclohexane, dibutylamine, N, N-dibutylaminopropylamine, diethanolamine, 2, 6-difluoroaniline, 2,5-difluoroaniline, diisopropylamine, 2- (3,4-dimethoxyphenyl) ethylamine, 2-tetrahydroperylamine, 3- (triethoxysilyl ) Propylamine, 2,3,4-trifluoroaniline, 3- (trifluoromethyl) benzylamine, 3,4,5-trimethoxyaniline, 3- (trimethoxysilyl) propylamine, 2- (on Amino) may be used either singly or in combination, such as ethanol, tris (hydroxymethyl) aminomethane.

Secondary coating compounds that impart a positive charge to the surface used in the present invention include 3-diethylamino-1-propylamine, N, N-dimethyl-1,4-phenyldiamine, N, N-dimethyl-1,3 -Phenyldiamine, 2,2-dimethylpropylenediamine, N, N-dimethyltrimethylenediamine, ethylenediamine, histaminedihydrochloride, N-isopropylethylenediamine, 2- (2-aminoethylamino) ethanol, N- ( 2-aminoethyl) morpholine, 2-amino-4-methylpyridine, 3- (aminomethyl) pyridine, 2- (aminomethyl) pyridine, 2-amino-5-methylpyridine, 2-amino-3-methylpyridine , 2-amino-5-methylthiazol, N, N'-bis (3-aminopropyl) butane-1,4-diamine, 2-aminopyridine, 4-aminopyridine, 3-aminopyridine, 2-aminopyri Midine, N'-benzyl-N, N-dimethylethylenediamine, 2,4,6-triamino-1,3,5-triazine, triethylenetetraamine, diethylenetriamine, N, N-diethylenediamine , N, N-diethyl-1,4-phenylenediamine, N, N'-dimethyl Ethylenediamine, N, N-diethylethylenediamine, N, N-dimethylethylenediamine, 2-methyl-1,5-diaminopentane, 4,4'-methylenebis (2-methylcyclohexylamine), N- Methylethylenediamine, 4-methyl-1,3-phenylenediamine, 4-methyl-1,2-phenylenediamine, 4-methyl-1,4-phenylenediamine, 3-morpholino-1-propylamine , 1,8-naphthalenediamine, 1,5-naphthalenediamine, pentaethylenehexaamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenylenediamine, piperazine, 2- ( 1-piperazinyl) ethylamine, tetraethylene pentaamine, etc. can be used individually or in mixture.

Secondary coating compounds that impart a negative charge to the surface used in the present invention include 4-aminonaphthalene-1-sulfonic acid, 1-amino-2-hydroxy-4-naphthalenesulfonic acid, N- [tris (hydr Oxymethyl) -methyl] -2-aminoethanesulfonic acid, sulfanilic acid, methanenilic acid, N- (2-acetamide) -2-aminoethanesulfonic acid, 2- (cyclohexylamino) ethanesulfonic Acid, taurine, 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid, N-methyltaurine, 4-aminonaphthalene-1-sulfonic acid, aminomethanesulfonic acid, 2-aminoethylhydrozene It can be used individually or in mixture with sulfate, 2-aminoethyl dihydrozen phosphate, 2-aminotoluene-5-sulfonic acid, etc.

When the compound is coated on the membrane, it is applied in a solution state using a suitable solvent of water, alcohols or mixtures thereof, wherein the content of the secondary coating compound is 0.00001 to 20% by weight (more preferably 0.0001 to 5% by weight). It is preferable to make ().

On the other hand, if necessary, an appropriate amount of additive is added to contact the surface of the polyamide composite thin film for 1 second to 10 minutes (more preferably, 5 seconds to 5 minutes) by the spray method, the T-die method, the dipping and the clad coating method. If necessary, the coated membrane is dried at 10 to 150 ° C. (more preferably at 20 to 100 ° C.) for 1 second to 7 days (more preferably, 5 seconds to 3 days) so as to promote the reaction by heat.

In the present invention, the appropriate amount of the additive is a method of increasing the reactivity with the unreacted acyl halide group of the polyamide composite thin film and the secondary coating compound, or adding a base catalyst or a surfactant alone or in combination.

As the above-mentioned base catalyst, compounds containing alkoxide salt, hydroxide salt, carbonate salt, phenoxide salt, carboxylate salt, tertiary amine, and the like are used. The above-mentioned surfactants use compounds containing cationic surfactants, anionic surfactants, nonionic surfactants, and the like.

As described above, the secondary coated polyamide composite membrane according to the present invention can obtain the effect of reducing contamination by proteins, macromolecules and colloids in various processes such as surface water treatment, protein separation, food and beverage purification. In addition, the membrane formed reverse osmosis membrane has an effect of increasing organic matter removal at lean concentration as in the manufacture of semiconductor ultrapure water or pharmaceutical ultrapure water.

The following examples and comparative examples are intended to illustrate the present invention more specifically, but do not limit the scope of the present invention.

Example 1

A 140 μm thick porous polysulfone support cast on a nonwoven fabric was immersed in 2 wt% metaphenylenediamine and 0.3 wt% 2-ethyl-1,3-hexanediol solution for 40 seconds to remove excess metaphenylenediamine solution from the support. After dipping in an organic solution of 0.1% by weight trimezoyl chloride for 1 minute using an isopar solvent as a solvent and then removing the excess organic solution and dried in air for 1 minute to form a polyamide composite thin film surface After spraying with a 0.2 wt% aqueous solution of ethanolamine for 20 seconds, the excess solution was removed, and then immersed in a 0.2% aqueous solution of sodium carbonate, washed with water at room temperature for 30 minutes, and then washed with pure water sufficiently to prepare a second polyamide composite membrane. It was.

Performance evaluation of the membrane prepared by the above method was confirmed the initial basic properties by measuring the permeate flow rate and salt excretion rate in a cross-flow method at 25 ℃, 225psi pressure condition using a 2,000ppm sodium chloride aqueous solution. As a result, 99.2% salt rejection and 29.6 gfd permeability were obtained. Then, under the same conditions, 30 ppm dry milk (the protein contained in the dry milk is present in the form of protein molecules in aqueous solution or in the form of colloids between protein molecules, these are easily adsorbed on the membrane surface) After cycling for 4 hours, separation and permeation were measured, yielding 99.4% and 28.3 gfd.

Comparative Example 1

Except not forming a secondary coating layer in Example 1 was carried out in the same manner as in Example 1 to prepare a polyamide composite membrane.

The separation membranes obtained in Example 1 and Comparative Example 1 were evaluated for their performance and are shown in Table 1 below.

Separator Initial salt removal rate (%) Initial Permeate Flow Rate (gfd) Permeate flow rate (gfd) after contamination resistance evaluation Permeate Flow Reduction Rate (%) Comparative Example 1 99.0 32.6 28.2 13.5 Example 1 99.2 29.6 28.3 4.4

In Table 1, in the case of Example 1, it can be seen that the transmission flow rate reduction rate is smaller than that of Comparative Example 1. This means that the permeate flow rate can be more stably obtained, and the system can be operated economically because it saves the trouble of changing the operating conditions such as periodic cleaning or pressure regulation. In addition, in the case of washing the contaminated membrane after fouling resistance evaluation, the initial physical properties of Example 1 are completely recovered, whereas Comparative Example 1 has only 80% of the initial physical properties, so that Comparative Example 1 is more strongly contaminated. It can be seen that.

Example 2

Polyamide in the same manner as in Example 1 except that 0.2 wt% 2-aminoethylenesulfonic acid (taurine) and 0.2% N, N, N ', N'-tetramethylhexenediamine were used instead of ethanolamine. Composite membranes were prepared.

Comparative Example 2

A polyamide reverse osmosis membrane was prepared in the same manner as in Example 2, except that no secondary coating layer was formed.

The performance of the separator obtained in Example 2 and Comparative Example 2 was evaluated and shown in Table 2 below.

Separator Initial salt removal rate (%) Initial Permeate Flow Rate (gfd) Permeate flow rate (gfd) after contamination resistance evaluation Permeate Flow Reduction Rate (%) Comparative Example 2 99.0 32.6 28.2 13.5 Example 2 99.1 33.7 31.6 6.2

As can be seen from Table 2, the secondary coating has a small permeation rate reduction rate.

Example 3

A polyamide composite membrane was prepared in the same manner as in Example 1, except that N, N-dimethylaminopropylamine was added instead of ethanolamine.

Comparative Example 3

A polyamide composite film was prepared in the same manner as in Example 3, except that the secondary coating layer was not formed in Example 3.

In order to evaluate the performance of the separation membrane obtained in Example 3 and Comparative Example 3, 50 ppm dodecyltrimethylammonium bromide (DTAB) was added instead of dry milk under the evaluation conditions of Example 1 to carry out contamination resistance evaluation. It is shown in 3. (DTAB is a cationic surfactant, which is strongly adsorbed on the surface of the separator by hydrophobic bonding and electrostatic attraction.)

Separator Initial salt removal rate (%) Initial Permeate Flow Rate (gfd) Permeate flow rate (gfd) after contamination resistance evaluation Permeate Flow Reduction Rate (%) Comparative Example 3 99.0 32.6 28.2 13.5 Example 3 98.9 36.2 36.0 0.5

As can be seen from Table 3, the secondary coating has a small transmission flow rate reduction rate.

As can be seen from the above examples and comparative examples, the polyamide composite membrane subjected to the secondary coating according to the present invention is particularly excellent in fouling resistance, thereby solving the disadvantages of the conventional separator such as deterioration of permeability of the membrane due to membrane contamination and frequent washing. It was.

Claims (14)

After forming a thin film of polyamide on the porous support, a secondary coating is applied on the polyamide composite membrane to prepare a polyamide composite membrane having improved separation performance, but the secondary coating is an unreacted acyl halide group in the polyamide composite membrane. A method for producing a polyamide composite membrane having excellent fouling resistance or separation performance by coating a compound having at least one functional group capable of reacting on a polyamide composite membrane and covalently bonding the acyl halide group. The polyamide thin film is excellent in fouling resistance or separation performance, characterized in that obtained by interfacial polymerization of an amine-reactive compound selected from the group consisting of polyamine and polyfunctional acyl halide, polyfunctional sulfonyl halide and polyfunctional isocyanate. Polyamide Composite Membrane Manufacturing Method. The method of claim 1, wherein the secondary coating compound has a functional group capable of controlling charge on the surface at the same time. The method of claim 1, wherein the secondary coating compound has amine, hydroxy, epoxy, etc. as a functional group capable of forming a covalent bond with an acyl halide. The method of claim 3, wherein the secondary coating compound is an alkyl group, benzene group, ether group, ester group, amide group, urea group, urethane, hydroxy group, siloxane group, phosphoric acid group, sulfonic acid group , Carboxyl group, amine group and the like. Specific examples of the functional group for controlling the surface charge include a) functional groups for neutralizing the surface charge include alkyl groups, benzene groups, hydroxy groups, siloxane groups, ether groups, ester groups, amide groups, urea groups, urethane groups, and the like. b) The functional groups that can control the surface charges to negative charges are carboxyl groups, sulfonic acid groups, and phosphate groups. c) The functional groups that can control the surface charges to positive charges are primary amines, secondary amines, tertiary amines and quaternary amines. Polyamide composite membrane manufacturing method excellent in fouling resistance or separation performance characterized by having an amine group. The compound for neutralizing the surface charge used as the secondary coating compound is arylamine, aminoacetaldehyde dimethylacetal, 2-aminobenzimidazole, 2-aminobenzothiazole, 2-aminoheptane, 2 -Amino-2-methyl-1,3-propanediol, 2-amino-2-methyl-1-propanol, 1-amino-2-propanol, 3-amino-1-propanol, aniline, 2-anilinoethanol, Benzylamine, 2- (benzylamino) ethanol, tertiarybutylamine, n-butylamine, N, O-dimethylhydroxylamine, dipropylamine, diethylamine, ethanolamine, ethylamine, 2- (ethylamino) Ethanol, perylamine, 4-hydroxy-3-methoxybenzylamine, 2- (4-hydroxy phenyl) ethylamine, 2- (3,4-dihydroxyphenyl) ethylamine, 1,1-imi Nodi-2-propanol, isobutylamine, isopentylamine, isopropylamine, 2-methoxybenzylamine, 4-methoxybenzylamine, bis (2-methoxyethyl) amine, 2-methoxyethylamine, 2 -(4-methox Phenyl) ethylamine, methylamine, (methylamino) acetaldehydedimethylacetal, 2- (methylamino) ethanol, 4-methylbenzylamine, N-methylbenzylamine, N-methylbutylamine, N-methylcyclohexylamine, D (-)-N-methylglucamine, N-methylhydroxylamine, O-methylhydroxylamine, n-pentylamine, propylamine, di-tert-butylamine, secondary-butylamine, cyclohexylamine , Cyclopentylamine, cyclopropanemethylamine, cyclopropylamine, diarylamine, 1,4-diaminobutane, 1,2-diamino cyclohexane, dibutylamine, N, N-dibutylaminopropylamine, di Ethanolamine, 2,6-difluoroaniline, 2,5-difluoroaniline, diisopropylamine, 2- (3,4-dimethoxyphenyl) ethylamine, 2-tetrahydroperylamine, 3- (Triethoxysilyl) propylamine, 2,3,4-trifluoroaniline, 3- (trifluoromethyl) benzylamine, 3,4,5-trimethoxyaniline, 3- (trimethoxysil ) Propylamine, 2- (ethylamino) ethanol, tris (hydroxymethyl) aminomethane, etc. alone or stain resistance or separation performance is excellent polyamide composite membrane manufacturing method which comprises applying a mixture to use. The compound for imparting a positive charge to the surface used as the secondary coating compound is 3-diethylamino-1-propylamine, N, N-dimethyl-1,4-phenyldiamine, N, N- Dimethyl-1,3-phenyldiamine, 2,2-dimethylpropylenediamine, N, N-dimethyltrimethylenediamine, ethylenediamine, histaminedihydrochloride, N-isopropylethylenediamine, 2- (2-aminoethylamino) Ethanol, N- (2-aminoethyl) morpholine, 2-amino-4-methylpyridine, 3- (aminomethyl) pyridine, 2- (aminomethyl) pyridine, 2-amino-5-methylpyridine, 2-amino -3-methylpyridine, 2-amino-5-methylthiazole, N, N'-bis (3-aminopropyl) butane-1,4-diamine, 2-aminopyridine, 4-aminopyridine, 3-aminopyridine , 2-aminopyrimidine, N'-benzyl-N, N-dimethylethylenediamine, 2,4,6-triamino-1,3,5-triazine, triethylenetetraamine, diethylenetriamine, N, N-diethylenediamine, N, N-diethyl-1,4-phenylene Amines, N, N'-dimethylethylenediamine, N, N-diethylethylenediamine, N, N-dimethylethylenediamine, 2-methyl-1,5-diaminopentane, 4,4'-methylenebis (2 -Methylcyclohexylamine), N-methylethylenediamine, 4-methyl-1,3-phenylenediamine, 4-methyl-1,2-phenylenediamine, 4-methyl-1,4-phenylenediamine, 3 -Morpholino-1-propylamine, 1,8-naphthalenediamine, 1,5-naphthalenediamine, pentaethylenehexaamine, 1,2-phenylenediamine, 1,3-phenylenediamine, 1,4-phenyl A method for producing a polyamide composite membrane having excellent fouling resistance or separation performance, characterized in that it is used alone or mixed with rendiamine, piperazine, 2- (1-piperazinyl) ethylamine, tetraethylenepentaamine, and the like. The compound for imparting a negative charge to the surface used as the secondary coating compound is 4-aminonaphthalene-1-sulfonic acid, 1-amino-2-hydroxy-4-naphthalenesulfonic acid, N -[Tris (hydroxymethyl) -methyl] -2-aminoethanesulfonic acid, sulfanilic acid, methanylalic acid, N- (2-acetamide) -2-aminoethanesulfonic acid, 2- (cyclohexyl Amino) ethanesulfonic acid, taurine, 4-amino-5-hydroxynaphthalene-2,7-disulfonic acid, N-methyltaurine, 4-aminonaphthalene-1-sulfonic acid, aminomethanesulfonic acid, 2 Preparation of polyamide composite membrane with excellent fouling resistance or separation performance, characterized in that it is used singly or in combination with aminoethylhydrogen sulfate, 2-aminoethyl dihydrozenphosphate, 2-aminotoluene-5-sulfonic acid, and the like. Way. The method of claim 1, wherein the secondary coating compound is applied to the polyamide separator in a solution state using a suitable solvent of water, alcohols or mixtures thereof, wherein the content of the secondary coating compound is 0.00001 to 20% by weight (More preferably 0.0001 to 5% by weight) polyamide composite membrane manufacturing method excellent in fouling resistance or separation performance, characterized in that. The method of claim 1, wherein when coating the secondary coating compound on the polyamide separation membrane, the surface of the polyamide composite thin film is sprayed for 1 second to 10 minutes (more preferably 5 seconds to 1 minute) by spraying, T-die, dipping, or clad coating. Method for producing a polyamide composite membrane excellent in fouling resistance or separation performance, characterized in that the contacting (5 minutes). The method according to claim 1, wherein when the secondary coating compound is coated on the polyamide separator, the coated separator is heated at 10 to 150 ° C (more preferably, 20 to 100 ° C) for 1 second to 7 so as to promote the reaction by heat. A method for producing a polyamide composite membrane having excellent fouling resistance or separation performance, which is dried for days (more preferably, 5 seconds to 3 days). The method according to claim 10, wherein when the secondary coating compound is coated on the polyamide separation membrane, a base catalyst or a surfactant is used alone or in a mixture to increase the reactivity between the secondary coating compound and the acyl halide. Or polyamide composite membrane having excellent separation performance. A polyolefin having excellent fouling resistance or separation performance, characterized by using a compound containing an alkoxide salt, a hydroxide salt, a carbonate salt, a phenoxide salt, a carboxylate salt, a tertiary amine, etc. as the base catalyst mentioned in claim 12. Amide Composite Membrane Manufacturing Method. A method for producing a polyamide composite membrane having excellent fouling resistance or separation performance, using a compound containing a cationic surfactant, an anionic surfactant, a nonionic surfactant, or the like as the surfactant mentioned in claim 12.