KR20200029195A - Membrane for Water Porcessing - Google Patents

Abstract

The present invention relates to a filtration membrane for water treatment. More specifically, the present invention relates to a filtration membrane for water treatment, which comprises a hydrophobic polymeric matrix and a specific hydrophilic polymeric coating layer on at least one surface of the hydrophobic polymeric matrix. The filtration membrane prevents the attachment of hydrophobic contaminants onto a surface of a separator, and also prevents the binding between the hydrophobic contaminants, has excellent mechanical properties, and exhibits high permeability and salt removal rate to be able to maintain anti-fouling properties due to long-term contamination.

Description

Filter membrane for water treatment {Membrane for Water Porcessing}

The present invention relates to a filter membrane for water treatment having excellent anti-fouling properties because the surface is modified by a hydrophilic polymer-based coating layer.

The water treatment method using a separator has advantages of less installation space, superior treatment capacity, and lower operating cost than existing technologies, and recently, it has been applied to various water treatment fields such as sewage treatment, seawater desalination treatment, household use, medical treatment, and industrial use. Is increasing.

They are divided into microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) separation membranes according to the size of the pores. The type of substance present is different.

Among them, microfiltration (MF) and ultrafiltration (UF) separation membranes that can be driven at low pressure can effectively remove contaminants such as colloidal particles or microorganisms, and have excellent physical properties and heat resistance as main components. , Polyvinylidenefluoride (PVDF), a polymer having chemical resistance, polysulfone (PSF), polyethersulfone (PES), polyacrylonitrile (PAN), and the like are used.

However, these materials form an interaction between the hydrophobic organic contaminant and the surface of the separator, thereby accelerating the contamination, thereby causing a decrease in the membrane performance such as a decrease in water permeability.

In addition, since many contaminants in sewage have electric charges, various methods such as coating a hydrophilic polymer, blending, modifying, or coating a material having a charge on the surface of the membrane have been tried to reduce contamination of the membrane.

Specifically, polyvinylidene fluoride (PVDF), the most commonly used material in the manufacturing process of membranes, exhibits hydrophobicity, and pure PVDF membranes tend to be contaminated by proteins and other impurities when purifying water or wastewater, resulting in a rapid flow of water in the membrane. There is a problem of falling.

So far, many researchers have studied to solve this, and a method of blending inorganic materials such as TiO ₂ and CNT with PVDF has been developed. However, this method has a problem that the effect is not very high and is expensive.

US Published Patent US2009 / 0283475 A1

 S.J. Oh, N. Kim, Y.T. Lee. "Preparation and characterization of PVDF / TiO2 organic-inorganic composite membranes for fouling resistance improvement". Journal of Membrane Science. Volume 345, Issues 1-2, 1 December 2009, Pages 13-20.  Y.H. Teow, A.L. Ahmad, J.K. Lim, B.S. Ooi. "Preparation and characterization of PVDF / TiO2 mixed matrix membrane via in situ colloidal precipitation method". Desalination. Volume 295, 1 June 2012, Pages 61-69.

An object of the present invention is to provide a filtration membrane for water treatment capable of maintaining anti-fouling properties due to long-term contamination due to excellent mechanical properties and high permeability and salt rejection rate.

The present invention comprises a hydrophobic polymer-based matrix and at least one surface of the hydrophobic polymer matrix, a hydrophilic polymer-based coating layer, wherein the hydrophilic polymer-based coating layer is 1) a compound having a hydrophilic group and a hydrophobic group represented by Formula 1, 2) graphene It provides an oxidized or reduced graphene oxide, and 3) quaternary ammonium compound to provide a filter membrane for water treatment.

[Formula 1]

XYL- (WZ) _n

(However, n is 1, 2 or 3 and X, Y, L, W and Z are defined as follows: X is strong and chemically and / or physically interactable with respect to a metal surface, and at least one acid group X ¹ or These salts, or terminal groups containing one or more hydrolyzable Si-containing groups X ² , Y is a hydrocarbon group having 5 to 60 carbon atoms, which contains substantially identical units bonded to each other linearly, and L is n = 1 L ¹ for L, L ² for n = ² , L ³ for n = 3 and L ¹ , L ² and L ³ defined as follows: L ¹ bonds the hydrophobic group Y to the hydrophilic group W It is a linear bond group, S, -SS-, -CO-O-, -O-CO-, -CO-NR ^1- , -NR ¹ -CO-, -O-CO-NR ^1- , -NR ¹ -CO Selected from the group consisting of -O-, -NR ¹ -CO-NR ¹ -and -NR ¹ -and L ² is a branched group that combines hydrophobic group Y with two hydrophilic groups W -N <, -NR ^1- CR ^{1 '} <, -CO-N <, -NR ¹ -CO-N <and -CO-NR ¹ -CR ^1' < Selected and L ³ is a branched group that combines the hydrophobic group Y with three hydrophilic groups W-NR ¹ -C≡, -NR ¹ -CH ₂ -C≡, -OC≡, -O-CH ₂ -C≡,- CO-NR ¹ -CH ₂ -C≡, -CO-NR ¹ -C≡, -CO-NR ¹ -CH ₂ -C≡, -CO-OC≡ and -CO-O-CH ₂ -C≡ Selected from the group (however, the symbol "≡" here represents three single bonds) (where R ¹ and R ^{1 '} are each independently H or C1 to C4 alkyl) and W is a hydrophilic group and Z Is a reactive end group Z ¹ or one of the non-reactive end groups Z ² and when L ¹ is -CO-O-, the first end group X is not -COOH).

In addition, the present invention comprises a hydrophobic polymer-based matrix and at least one surface of the hydrophobic polymer matrix, a hydrophilic polymer-based coating layer, wherein the hydrophilic polymer-based coating layer is 1) a compound having a hydrophilic group and a hydrophobic group represented by Formula 1, 2) Provided is a filtration membrane for water treatment, characterized in that it contains a perchlorate-based inorganic additive, and 3) a quaternary ammonium compound.

In addition, the present invention consists of a hydrophobic polymer matrix and at least one surface of the hydrophobic polymer matrix, a hydrophilic polymer coating layer, the hydrophilic polymer coating layer is 1) hydrophilic polymer, 2) amphiphilic particles, 3) graphene oxide or It provides a filtered membrane for water treatment, characterized in that it contains a reduced graphene oxide, and 4) quaternary ammonium compounds.

In addition, the present invention consists of a hydrophobic polymer matrix and at least one surface of the hydrophobic polymer matrix, a hydrophilic polymer coating layer, wherein the hydrophilic polymer coating layer is 1) hydrophilic polymer, 2) amphiphilic particles, 3) perchlorate inorganic additive , And 4) a quaternary ammonium compound.

The filtration membrane for water treatment according to the present invention has an effect of preventing hydrophobic contaminants from adhering to the surface of the separation membrane and preventing binding between hydrophobic contaminants.

In addition, the filtration membrane for water treatment according to the present invention has the effect of controlling the surface roughness, improving hydrophilicity, and adding antibacterial properties to improve anti-fouling properties.

In addition, the filtration membrane for water treatment according to the present invention has an effect of maintaining not only the anti-fouling properties, but also excellent mechanical properties, and high permeability and salt rejection rate, thereby maintaining anti-fouling properties due to long-term contamination.

Therefore, due to these improved properties, wastewater treatment, filtration of juices or alcoholic beverages, ultrapure water production used in semiconductor manufacturing, metal recovery, pasteurization of beverages and pharmaceuticals, medical treatment, continuous culture, purification of condensate in nuclear power plants, etc. It is expected to be very useful in such fields.

In particular, by manufacturing the membrane in the form of a module and applying it to a water treatment device, it can be more useful when applied to an actual separation process.

The present invention relates to a filter membrane for water treatment having excellent anti-fouling properties because the surface is modified by a hydrophilic polymer-based coating layer.

Prior to this, the terms or words used in the present specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately explains the concept of terms in order to explain his or her invention in the best way. Based on the principle that it can be defined, it should be interpreted as meanings and concepts consistent with the technical spirit of the present invention.

Therefore, the configuration shown in the embodiments and drawings described in this specification are only the most preferred embodiment of the present invention, and do not represent all the technical spirit of the present invention, and at the time of this application, they can be replaced. It should be understood that there may be various equivalents and variations.

Hereinafter, a filtration membrane for water treatment according to the present invention will be described in detail.

The filtration membrane for water treatment according to the present invention comprises a hydrophobic polymer-based matrix and a hydrophilic polymer-based coating layer on at least one surface of the hydrophobic polymer matrix.

The hydrophilic polymer-based coating layer may contain 1) a compound having a hydrophilic group and a hydrophobic group represented by Chemical Formula 1, 2) graphene oxide or reduced graphene oxide, and 3) a quaternary ammonium compound.

In addition, the hydrophilic polymer-based coating layer may contain 1) a compound having a hydrophilic group and a hydrophobic group represented by Chemical Formula 1, 2) a perchlorate-based inorganic additive, and 3) a quaternary ammonium compound.

In addition, the hydrophilic polymer-based coating layer may contain 1) a hydrophilic polymer, 2) amphiphilic particles, 3) graphene oxide or reduced graphene oxide, and 4) a quaternary ammonium compound.

In addition, the hydrophilic polymer-based coating layer may contain 1) a hydrophilic polymer, 2) amphiphilic particles, 3) a perchlorate-based inorganic additive, and 4) a quaternary ammonium compound.

Looking at the components forming the hydrophilic polymer-based coating layer according to the present invention in more detail as follows.

The hydrophobic polymer forming the polymer matrix is generally used in the art, and is not particularly limited, but polyacrylonitrile (PAN), polysulfone (PSF), polyethersulfone (PES), polyimide (PI), poly Any one selected from the group consisting of etherimide (PEI), polyamide (PA), cellulose acetate (CA), cellulose triacetate (CTA) and polyvinylidene fluoride (PVDF) can be preferably used. Particularly, when it contains graphene oxide or reduced graphene oxide, polyacrylonitrile having excellent chemical stability and capable of interacting with a hydroxyl group and a carboxyl group on a graphene oxide surface through hydrogen bonding is more preferably used.

The compound of the formula (1) contained in the hydrophilic polymer-based coating layer is a compound having a hydrophilic group and a hydrophobic group at the same time. The hydrophilic group of Chemical Formula 1 suppresses fouling by preventing binding to a hydrophobic contaminant, and the hydrophobic group increases miscibility with the matrix, thereby improving long-term durability of the coating layer. The compound can be synthesized or a commercially available compound can be used.

[Formula 1]

XYL- (WZ) _n

(However, n is 1, 2 or 3 and X, Y, L, W and Z are defined as follows: X is strong and chemically and / or physically interactable with respect to a metal surface, and at least one acid group X ¹ or These salts, or terminal groups containing one or more hydrolyzable Si-containing groups X ² , Y is a hydrocarbon group having 5 to 60 carbon atoms, which contains substantially identical units bonded to each other linearly, and L is n = 1 L ¹ for L, L ² for n = ² , L ³ for n = 3 and L ¹ , L ² and L ³ defined as follows: L ¹ bonds the hydrophobic group Y to the hydrophilic group W It is a linear bond group, S, -SS-, -CO-O-, -O-CO-, -CO-NR ^1- , -NR ¹ -CO-, -O-CO-NR ^1- , -NR ¹ -CO Selected from the group consisting of -O-, -NR ¹ -CO-NR ¹ -and -NR ¹ -and L ² is a branched group that combines hydrophobic group Y with two hydrophilic groups W -N <, -NR ^1- CR ^{1 '} <, -CO-N <, -NR ¹ -CO-N <and -CO-NR ¹ -CR ^1' < Selected and L ³ is a branched group that combines the hydrophobic group Y with three hydrophilic groups W-NR ¹ -C≡, -NR ¹ -CH ₂ -C≡, -OC≡, -O-CH ₂ -C≡,- CO-NR ¹ -CH ₂ -C≡, -CO-NR ¹ -C≡, -CO-NR ¹ -CH ₂ -C≡, -CO-OC≡ and -CO-O-CH ₂ -C≡ Selected from the group (however, the symbol "≡" here represents three single bonds) (where R ¹ and R ^{1 '} are each independently H or C1 to C4 alkyl) and W is a hydrophilic group and Z Is a reactive end group Z ¹ or one of the non-reactive end groups Z ² and when L ¹ is -CO-O-, the first end group X is not -COOH).

In addition, the present invention may perform the same role as above by using amphipathic particles instead of the compound of Formula 1. In the amphiphilic particles, a part of the surface of the hydrophilic inorganic particles is coated with a lipophilic material. Specifically, one or more lipophilic materials selected from the group consisting of silane compounds, titanate-based coupling agents, oily polydispersed anionic surfactants, oil-soluble polyamine condensates, polyamide resins, and water-insoluble polymer compounds are coated on the surface of the hydrophilic inorganic particles. Can be used. As the hydrophilic inorganic particles, carbonate, silicate, sulfate, and hydroxide of silicon dioxide or metal may be used, and specifically, oxides such as silicon dioxide (silica, silica stone), alumina, titanium dioxide, heavy or light calcium carbonate, magnesium carbonate, etc. And silicates such as carbonate, kaolin, mud and talc, hydroxides such as aluminum hydroxide and magnesium hydroxide, and sulfates such as barium sulfate and calcium sulfate. These amphiphilic particles may be manufactured by a method commonly used in the art, or a commercialized product may be used. For example, after mixing and stirring a solution containing a hydrophilic inorganic particle and a lipophilic substance under a volatile organic solvent, the volatile organic solvent may be dried to remove the amphiphilic particles.

Graphene oxide or reduced graphene oxide and perchlorate-based inorganic additives serve to increase the resistance to contaminants by controlling the surface roughness of the hydrophilic polymer coating layer. In particular, the graphene oxide or the reduced graphene oxide may simultaneously serve to enhance hydrophilicity.

The graphene oxide can be prepared in large quantities by oxidizing graphite using an oxidizing agent, and includes a hydrophilic functional group such as a hydroxyl group, a carboxyl group, a carbonyl group, or an epoxy group. Currently, graphene oxide is mostly Hummers method [Hummers, WS & Offeman, RE Preparation of graphite oxide. J. Am. Chem . Soc . 80 . 1339 (1958)], or some modified Hummers 'method, to obtain graphene oxide according to the modified Hummers' method in the present invention.

In addition, graphene oxide is a functional group converted to an ester group, an ether group, an amide group, or an amino group by chemically reacting a hydrophilic functional group such as a hydroxyl group, a carboxyl group, a carbonyl group, or an epoxy group present in the graphene oxide with another compound. Graphene oxide may also be used. For example, the carboxyl group of graphene oxide is converted to an ester group by reaction with an alcohol, the hydroxyl group of graphene oxide is converted to an ether group by reaction with an alkyl halide, and the carboxyl group of graphene oxide is reacted with an alkyl amine Some may be converted to an amide group, or an epoxy group of graphene oxide converted to an amino group by ring-opening reaction with an alkyl amine. In addition, in the present invention, in addition to the graphene oxide (GO), a reduced graphene oxide (rGO) in which graphene oxide is reduced by a known chemical or thermal reduction method may be used.

The perchlorate-based inorganic additive is KClO ₄ , LiClO ₄ , NaClO ₄ , Mg (ClO ₄ ) ₂ , Be (ClO ₄ ) ₂ and Ca (ClO ₄ ) ₂ One or more selected from the group consisting of may be used, preferably, KClO ₄ may be used.

The quaternary ammonium compound serves to necroticize cells by destabilizing the bacterial cell membrane surface material of the quaternary ammonium compound. The quaternary ammonium compound may specifically use 3- (trimethoxysilyl) -propyldimethyloctadecylammonium chloride.

The hydrophilic polymer is generally used in the art, and is not particularly limited, and specifically, a polymer having OH, -NH2, -CN, -CO-, -COOH, and -CONH- functional groups may be used. For example, PMMA-b-PPEGMEMA {Polymethyl Methacrylate-b-Poly (polyethylene glycol methyl ether methacrylate)}, a copolymer of PPEGMEMA {Poly (polyethylene glycol methyl ether methacrylate)}, alkoxy poly (oxyethylene) (meth) acrylate, Hydrophilic PVDF-g-PSPMA (polyvinylidene fluoride graft-g-polysulfopropyl methacrylate) copolymer or the like can be used.

The hydrophilic polymer-based coating layer according to the present invention can be formed on the surface of a hydrophobic polymer-based matrix using a coating method generally used in the art. In addition, the content of the component forming the hydrophilic polymer-based coating layer may be appropriately adjusted in consideration of the transmittance of the filtration membrane, anti-fouling property, and long-term durability of the membrane.

The above description is merely illustrative of the technical spirit of the present invention, and those of ordinary skill in the art to which the present invention pertains can be modified and modified in various ways without departing from the essential characteristics of the present invention. The protection scope of should be interpreted by the claims below, and all technical spirits within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (8)

Hydrophobic polymer matrix and
At least one surface of the hydrophobic polymer matrix, made of a hydrophilic polymer-based coating layer,
The hydrophilic polymer-based coating layer is 1) a compound having a hydrophilic group and a hydrophobic group represented by the formula (1), 2) graphene oxide or reduced graphene oxide, and 3) quaternary ammonium compound, characterized in that it contains a filtration membrane for water treatment :
[Formula 1]
XYL- (WZ) _n
(However, n is 1, 2 or 3 and X, Y, L, W and Z are defined as follows: X is strong and chemically and / or physically interactable with respect to a metal surface, and at least one acid group X ¹ or These salts, or terminal groups containing one or more hydrolyzable Si-containing groups X ² , Y is a hydrocarbon group having 5 to 60 carbon atoms, which contains substantially identical units bonded to each other linearly, and L is n = 1 L ¹ for L, L ² for n = ² , L ³ for n = 3 and L ¹ , L ² and L ³ defined as follows: L ¹ bonds the hydrophobic group Y to the hydrophilic group W It is a linear bond group, S, -SS-, -CO-O-, -O-CO-, -CO-NR ^1- , -NR ¹ -CO-, -O-CO-NR ^1- , -NR ¹ -CO Selected from the group consisting of -O-, -NR ¹ -CO-NR ¹ -and -NR ¹ -and L ² is a branched group that combines hydrophobic group Y with two hydrophilic groups W -N <, -NR ^1- CR ^{1 '} <, -CO-N <, -NR ¹ -CO-N <and -CO-NR ¹ -CR ^1' < Selected and L ³ is a branched group that combines the hydrophobic group Y with three hydrophilic groups W-NR ¹ -C≡, -NR ¹ -CH ₂ -C≡, -OC≡, -O-CH ₂ -C≡,- CO-NR ¹ -CH ₂ -C≡, -CO-NR ¹ -C≡, -CO-NR ¹ -CH ₂ -C≡, -CO-OC≡ and -CO-O-CH ₂ -C≡ Selected from the group (however, the symbol "≡" here represents three single bonds) (where R ¹ and R ^{1 '} are each independently H or C1 to C4 alkyl) and W is a hydrophilic group and Z Is a reactive end group Z ¹ or one of the non-reactive end groups Z ² and when L ¹ is -CO-O-, the first end group X is not -COOH).
Hydrophobic polymer matrix and
At least one surface of the hydrophobic polymer matrix, made of a hydrophilic polymer-based coating layer,
The hydrophilic polymer-based coating layer is 1) a compound having a hydrophilic group and a hydrophobic group represented by Formula 1, 2) a perchlorate-based inorganic additive, and 3) a filtration membrane for water treatment, characterized in that it contains a quaternary ammonium compound:
[Formula 1]
XYL- (WZ) _n
(However, n is 1, 2 or 3 and X, Y, L, W and Z are defined as follows: X is strong and chemically and / or physically interactable with respect to a metal surface, and at least one acid group X ¹ or These salts, or terminal groups containing one or more hydrolyzable Si-containing groups X ² , Y is a hydrocarbon group having 5 to 60 carbon atoms, which contains substantially identical units bonded to each other linearly, and L is n = 1 L ¹ for L, L ² for n = ² , L ³ for n = 3 and L ¹ , L ² and L ³ defined as follows: L ¹ bonds the hydrophobic group Y to the hydrophilic group W It is a linear bond group, S, -SS-, -CO-O-, -O-CO-, -CO-NR ^1- , -NR ¹ -CO-, -O-CO-NR ^1- , -NR ¹ -CO Selected from the group consisting of -O-, -NR ¹ -CO-NR ¹ -and -NR ¹ -and L ² is a branched group that combines hydrophobic group Y with two hydrophilic groups W -N <, -NR ^1- CR ^{1 '} <, -CO-N <, -NR ¹ -CO-N <and -CO-NR ¹ -CR ^1' < Selected and L ³ is a branched group that combines the hydrophobic group Y with three hydrophilic groups W-NR ¹ -C≡, -NR ¹ -CH ₂ -C≡, -OC≡, -O-CH ₂ -C≡,- CO-NR ¹ -CH ₂ -C≡, -CO-NR ¹ -C≡, -CO-NR ¹ -CH ₂ -C≡, -CO-OC≡ and -CO-O-CH ₂ -C≡ Selected from the group (however, the symbol "≡" here represents three single bonds) (where R ¹ and R ^{1 '} are each independently H or C1 to C4 alkyl) and W is a hydrophilic group and Z Is a reactive end group Z ¹ or one of the non-reactive end groups Z ² and when L ¹ is -CO-O-, the first end group X is not -COOH).
Hydrophobic polymer matrix and
At least one surface of the hydrophobic polymer matrix, made of a hydrophilic polymer-based coating layer,
The hydrophilic polymer-based coating layer is 1) hydrophilic polymer, 2) amphiphilic particles, 3) graphene oxide or reduced graphene oxide, and 4) filtration membrane for water treatment, characterized in that it contains a quaternary ammonium compound.
Hydrophobic polymer matrix and
At least one surface of the hydrophobic polymer matrix, made of a hydrophilic polymer-based coating layer,
The hydrophilic polymer-based coating layer is 1) hydrophilic polymer, 2) amphiphilic particles, 3) perchlorate-based inorganic additives, and 4) filtration membrane for water treatment, characterized in that it contains a quaternary ammonium compound.
The method according to claim 3 or claim 4, wherein the amphiphilic particles are made of a silane compound, a titanate-based coupling agent, an oily polydisperse anionic surfactant, a fat-soluble polyamine condensate, a polyamide resin, and a water-insoluble polymer compound on the surface of a hydrophilic inorganic particle. Filtration membrane for water treatment, characterized in that at least one lipophilic material selected from the group is coated
The method according to any one of claims 1 to 4, wherein the hydrophobic polymer matrix is polyacrylonitrile, polysulfone, polyethersulfone, polyimide, polyetherimide, polyamide, cellulose acetate, cellulose triacetate and polyvinylidene fluoride A filter membrane for water treatment, characterized in that it consists of any one hydrophobic polymer selected from the group consisting of rides.
The filtration membrane for water treatment according to any one of claims 1 to 4, wherein the quaternary ammonium compound is 3- (trimethoxysilyl) -propyldimethyloctadecylammonium chloride.
The method according to claim 2 or claim 4, The perchlorate-based inorganic additive is at least one kind from the group consisting of KClO ₄ , LiClO ₄ , NaClO ₄ , Mg (ClO ₄ ) ₂ , Be (ClO ₄ ) ₂ and Ca (ClO ₄ ) ₂ . It characterized in that the filtration membrane for water treatment is selected.