KR20100078812A - Manufacturing method for polyamide-based reverse osmosis membrane and polyamide-based reverse osmosis membrane manufactured thereby - Google Patents

Abstract

PURPOSE: A manufacturing method of a polyamide-based reverse osmosis membrane and the polyamide-based reverse osmosis membrane manufactured thereby are provided to easily manufacture the polyamide-based reverse osmosis membrane with a multi-functional amine aqueous solution. CONSTITUTION: A manufacturing method of a polyamide-based reverse osmosis membrane includes the following steps: coating a mcroporous support with a multi-functional amine aqueous solution including benzoic acid and a benzoic acid derivative of 0.01-9.9 weight%; forming a membrane by interfacial polymerization after contacting an aliphatic hydrocarbon system organic solution including multi-functional acyl halide; and washing the acquired membrane.

Description

Method for producing a polyamide reverse osmosis membrane and a polyamide reverse osmosis membrane produced by the present invention TECHNICAL FIELD

The present invention relates to a method for preparing a polyamide reverse osmosis membrane and a polyamide reverse osmosis membrane produced by the same, and more particularly, to a polyamide reverse osmosis membrane having a high salt excretion rate and increased flux. It relates to a method for producing and a polyamide-based reverse osmosis membrane prepared thereby.

Osmotic phenomenon is a phenomenon in which a solvent moves from a solution having a low solute concentration to a high solution between two solutions separated by a semi-permeable membrane. It is called osmotic pressure. On the contrary, if the external pressure is applied higher than the osmotic pressure, the solvent moves toward the solution of low solute concentration. This phenomenon is called reverse osmosis. Through this, various salts and organic substances can be separated. That is, reverse osmosis membranes can be used to separate the water from the brine by pressurizing it to prevent passage of the salt and other dissolved ions or molecules.

The purpose of the reverse osmosis process is largely divided into the production of purified water and the concentration of solutes dissolved in raw water. The former includes the desalination of seawater and brine, the manufacture of ultrapure water for semiconductor industry, and the treatment of various industrial wastewater. And vegetable juice concentrates, low-alcohol beer and wine production.

The possibility of desalination of water using this reverse osmosis process was first presented by Reid in 1953, and in 1964 by Lobe and Sourirajan as cellulose acetate, A monolithic asymmetric membrane with a commercial potential consisting of a porous support underneath was prepared, and then polyamide, polyurethane, aromatic polysulfone, and aromatics were used to compensate for the shortcomings of the cellulose membrane. Research has been actively conducted on polyamides and the like.

The reverse osmosis membrane is divided into a monolithic asymmetric membrane and a thin film composite membrane according to the internal structure. The asymmetric membrane is composed of the same material as the salt excretion layer and the porous support under it, and is easy to manufacture and inexpensive, but has a low salt excretion rate and a low permeability. There is this. In recent years, thin film composite membranes have been developed in which the epidermal layer and the support layer are different from each other. Such composite membranes can select the optimal active layer material to improve the overall performance of the membrane as well as to crosslink the active layer. Since it can be given to have a high chemical resistance can be obtained.

In order to desalize a large amount of the reverse osmosis membrane commercially, the salt removal rate must be high, and the permeate flow rate characteristic of allowing excess water to pass through the membrane at a relatively low pressure must be excellent. Therefore, there is a demand for the development of a more economical process for producing a reverse osmosis membrane having a high salt rejection rate and high flow characteristics.

One embodiment of the present invention is to provide a method for producing a polyamide reverse osmosis membrane that can easily prepare a polyamide reverse osmosis membrane using a polyfunctional aqueous amine solution containing one or more of benzoic acid and benzoic acid derivatives. .

Another embodiment of the present invention is to provide a polyamide-based reverse osmosis membrane having a high salt removal rate and a high flow rate characteristics by the preparation method.

According to one embodiment of the invention, coating the microporous support with an aqueous polyfunctional amine solution containing 0.01 to 9.9% by weight of one or more of benzoic acid and benzoic acid derivatives;

Contacting an aliphatic hydrocarbon-based organic solution including polyfunctional acyl halide on the microporous support coated with the polyfunctional amine aqueous solution to form a thin film by interfacial polymerization; And

It provides a method for producing a polyamide reverse osmosis membrane comprising the step of drying and washing the thin film obtained in the previous step.

According to another embodiment of the present invention, there is provided a polyamide reverse osmosis membrane formed by the above method.

The polyamide-based reverse osmosis membrane of the embodiments of the present invention has a high salt removal rate and has a high flow rate, and thus may be usefully used for salt water and seawater treatment.

Hereinafter, embodiments of the present invention will be described in detail.

Method for producing a polyamide reverse osmosis membrane according to an embodiment of the present invention comprises the steps of coating the microporous support with a polyfunctional amine aqueous solution containing 0.01 to 9.9% by weight of one or more of benzoic acid and benzoic acid derivatives;

Contacting an aliphatic hydrocarbon-based organic solution including polyfunctional acyl halide on the microporous support coated with the polyfunctional amine aqueous solution to form a thin film by interfacial polymerization; And

Drying and washing the thin film obtained in the previous step in air.

Looking at this in more detail, after coating the polyfunctional aqueous solution containing at least one of benzoic acid and benzoic acid derivative on the microporous support, the excess solution is removed using a roll, air knife or sponge. The microporous support coated with the polyfunctional amine aqueous solution is then contacted with the polyfunctional acyl halide. At this time, the polyamide is produced by the reaction of the polyfunctional amine and the polyfunctional acyl halide, and the microporous support is adsorbed to form a thin film. Thereafter, the thin film may be dried and washed to prepare a polyamide-based reverse osmosis membrane having a high flow rate characteristic.

The microporous support may be a polymer material cast on a nonwoven fabric, such polymers include polysulfone, polyethersulfone, polycarbonate, polyphenylene oxide, polyimide ( polyimide, polyetherimide, polyetheretherketone, polypropylene, polymethylpentene, polymethyl chloride, and polyvinylidenefluoride It may be selected from the group consisting of, but is not necessarily limited to these.

The pore size of the microporous support which can be used in the present invention is preferably 1 to 500 nm, and when the pore size is 500 nm or more, it is difficult to form a uniform structure by the coating layer penetrating between the pores.

In this case, a continuous process or handy coating may be used as a method of coating the polyfunctional aqueous solution on the microporous support. The polyfunctional amine used herein is an aromatic polyfunctional amine substituted with an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a hydroxyalkyl group, a hydroxy group or a halogen atom, or benzidine, diaminobenzidine or alkyl. Or a polyfunctional amine such as a benzidine derivative substituted with a halogen atom or the like, and naphthalenediamine. More specific examples of the polyfunctional amine that can be used in the embodiments of the present invention include o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine. , 1,3,5-benzenetriamine, 4-chloro-1,3-phenylenediamine, 5-chloro-1,3 -Phenylenediamine (5-chloro-1,3-phenylenediamine) or 3-chloro-1,4-phenylenediamine, and the like, but are not limited thereto. no.

At this time, the polyfunctional amine of the aqueous polyfunctional amine solution is preferably included 0.1 to 20% by weight, more preferably 1.0 to 10% by weight, most preferably 1.5 to 4% by weight may be used.

In addition, according to one embodiment of the present invention, the aqueous polyfunctional amine solution further comprises sodium lauryl sulfate, sodium dodecylbenzenesulfonate, camphorsulfonic acid as an additive. It may include. In addition, the polyfunctional amine aqueous solution may further include sodium acetate, sodium bicarbonate or triethylamine as an acid acceptor.

On the other hand, the polyfunctional amine aqueous solution may include a polar compound such as benzoic acid or benzoic acid derivatives. The benzoic acid or benzoic acid derivatives used as such polar compounds improve the diffusion of diamine into the organic layer at the time of interfacial polymerization with acyl halides on the surface of the microporous support to increase the roughness of the polyamide surface layer, thus prepared The flow rate of the membrane is improved. In addition, since the separation membrane is prevented from drying while the excess organic solvent is evaporated after the interfacial polymerization reaction with the polyfunctional acyl halide, the flow rate of the separator can be increased.

Such benzoic acid derivatives are benzoic acid substituted with one or more substituents selected from the group consisting of hydrogen, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylsulfonyl group having 1 to 6 carbon atoms, and a nitro group. Can be. More specific examples include 3-hydroxybenzoic acid, 4-hydroxybenzoic acid, 2,3-dihydroxybenzoic acid, 2,5- 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2-ethoxybenzoic acid, 4-ethoxybenzoic acid (4- ethylbenzoic acid), 3-methoxybenzoic acid, 4-methoxybenzoic acid, 4-butthoxybenzoic acid, 2,4,5-trimethoxybenzoic acid (2,4,5-trimethoxybenzoic acid), 4-fluorobenzoic acid, 5-methyl-2-nitrobenzoic acid, 4- (methylsulfonyl) benzoic acid (4- (methylsulfonyl) benzoic acid), 2-sulfobenzoic acid, 2-chlorobenzoic acid, 4-chlorobenzoic acid, 2,3-dimethylbenzoic acid ( 2,3-dimethylbenzoic acid), 2,4-dimethylbenzoic acid, 2,5- Methylbenzoic acid (2,5-dimethylbenzoic acid), or 4-isopropyl-benzoic acid (4-isopropylbenzoic acid) and the like. However, it is not necessarily limited thereto.

In this case, the benzoic acid or benzoic acid derivative in the polyfunctional amine aqueous solution is preferably included in an amount of 0.01 to 9.9% by weight, more preferably 0.02 to 5% by weight, most preferably 0.02 to 3% by weight.

On the other hand, contact of the aliphatic hydrocarbon-based organic solution including the coated microporous support and the polyfunctional acyl halide may be performed by a dipping or spray method, but is not necessarily limited thereto.

In this case, the aliphatic hydrocarbon-based organic solution that can be used may include 0.01 to 1% by weight of at least one polyfunctional acyl halide selected from the group consisting of trimezoyl chloride, isophthaloyl chloride and terephthaloyl chloride.

In addition, the aliphatic hydrocarbon solvent used should not participate in the interfacial polymerization reaction, be free of chemical bonds with the polyfunctional acyl halide, and satisfy the condition that the porous support layer should not be damaged.

Non-limiting examples of aliphatic hydrocarbon solvents usable in the present invention include, but are not limited to, IsoPar (Exxon), ISOL-C (SK Chem.), ISOL-G (SK Chem.), And the like.

Subsequently, the thin film formed on the microporous support is dried and washed. At this time, drying may be performed by drying the said thin film at normal temperature, and drying for 30 second-10 minutes in the state of 30-120 degreeC, when the solvent is considered to have evaporated to some extent. The washing method is not particularly limited, but may be, for example, washed in a basic aqueous solution. At this time, the basic aqueous solution that can be used is not particularly limited, for example, an aqueous sodium carbonate solution can be used. Specifically, it may be washed for 30 minutes to 1 hour in 20 ~ 80 ℃ sodium carbonate aqueous solution.

Another embodiment of the present invention relates to a polyamide-based reverse osmosis membrane formed by the above method. The polyamide-based reverse osmosis membrane has a high salt rejection rate and has a high flow rate characteristic, so that the polyamide-based reverse osmosis membrane may be usefully used for desalination of seawater and brine, preparation of ultrapure water for semiconductor industry, and treatment of various industrial wastewater.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

Example  One

A solution containing 82% by weight of dimethylformamide and 18% by weight of polysulfone on a polyester nonwoven fabric was cast to 160 μm in thickness and immediately immersed in a distilled water coagulating solution at 25 ° C. to solidify, followed by a nonwoven fabric-reinforced poly The sulfone microporous substrate was washed with water sufficiently to replace the solvent and water in the substrate and then stored in pure water. Thus obtained polysulfone microporous support 2% by weight metaphenylenediamine, 1.5% by weight benzoic acid, 0.2% by weight sodium lauryl sulfate (SLS), 2.2% by weight camphorsulfonic acid, 4.4% by weight triethylamine And it was immersed in the polyfunctional amine aqueous solution containing water as the remaining amount for 2 minutes to remove the water on the surface. The microporous support coated with the aqueous polyfunctional amine solution was impregnated with an organic solution in which 0.1% by weight of trimezoyl chloride was dissolved in a solvent of IsoPar, EXXON, for 1 minute, and then dried in air and 0.2% by weight of sodium carbonate. After washing for 30 minutes on an aqueous solution containing, washed again with pure water at room temperature to prepare a polyamide reverse osmosis membrane, the flow rate and salt excretion rate were measured and the results are shown in Table 1 below.

Example  2

In the present Example, as shown in Table 1, except that 1.2% by weight of benzoic acid was used to prepare a polyamide reverse osmosis membrane in the same manner as in Example 1, and evaluated the characteristics and the results together with Table 1 Indicated.

Example  3

In the present Example, as shown in Table 1, except that 0.8 wt% of benzoic acid was used to prepare a polyamide reverse osmosis membrane in the same manner as in Example 1, and evaluated the characteristics and the results together with Table 1 Indicated.

Example  4-19

Example 4-19 is a polyamide reverse osmosis membrane prepared in the same manner as in Example 1 except for using a benzoic acid derivative instead of benzoic acid by varying the type and content, as shown in Table 1, and evaluated the characteristics The results are shown in Table 1 together.

<Method for evaluating the properties of reverse osmosis membrane>

① Flow rate evaluation

The flow rate was passed through a 2,000 ppm NaCl aqueous solution through a reverse osmosis membrane at 25 ℃, 225 psi conditions, and then the permeate flow rate was measured.

② Evaluation of salt exclusion rate

Salt exclusion rate was calculated by the following equation.

Where R is the salt magnification, C _f is the concentration of the solute in the feed water, and C _p is the concentration of the solute in the permeate.

Comparative example  One

2% by weight of metaphenylenediamine, 0.2% by weight of sodium lauryl sulfate (SLS), 2.2% by weight of camphorsulfonic acid, 4.4% by weight of triethylamine, without the use of benzoic acid or benzoic acid derivatives in aqueous polyfunctional amine solution After the separation membrane was prepared in the same manner as in Example 1 except that water was used as the residual amount, the properties were evaluated. As a result, the salt rejection ratio was 98.7% and the flow rate was 28.3 gfd.

Claims (11)

Coating the microporous support with an aqueous polyfunctional amine solution containing 0.01 to 9.9% by weight of one or more of benzoic acid and a benzoic acid derivative; Contacting an aliphatic hydrocarbon-based organic solution including polyfunctional acyl halide on the microporous support coated with the polyfunctional amine aqueous solution to form a thin film by interfacial polymerization; And Method for producing a polyamide reverse osmosis membrane comprising the step of drying and washing the thin film obtained in the previous step. The method of claim 1, wherein the microporous support is polysulfone, polyethersulfone, polycarbonate, polyethylene oxide, polyimide, polyetherimide, Polyetheretherketone, polypropylene, polymethylpentene, polymethylpentene, polymethyl chloride, and polyvinylidene fluoride; Method for producing a polyamide reverse osmosis membrane to be. According to claim 1, wherein the pore size of the microporous support is a method for producing a polyamide reverse osmosis membrane, characterized in that 1 to 500nm. The method of claim 1, wherein the polyfunctional amine contained in the aqueous polyfunctional amine solution is m-phenylenediamine (m-phenylenediamine), p-phenylenediamine (p-phenylenediamine), 1,3,5-benzenetriamine ( 1,3,5-benzenetriamine), 4-chloro-1,3-phenylenediamine, 5-chloro-1,3-phenylenediamine (5-chloro-1, 3-phenylenediamine), 3-chloro-1,4-phenylenediamine (3-chloro-1,4-phenylenediamine) and a method for producing a polyamide reverse osmosis membrane, characterized in that selected from the group consisting of . The method of claim 1, wherein the aqueous polyfunctional amine solution comprises 0.1 to 20% by weight of a polyfunctional amine. The method of claim 1, wherein the aqueous polyfunctional amine solution is sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium acetate, sodium bicarbonate, camphorsulfonic acid or triglyceride Method for producing a polyamide reverse osmosis membrane, characterized in that it further comprises ethylamine. The benzoic acid derivative according to claim 1, wherein the benzoic acid derivative is at least one selected from the group consisting of hydrogen, a hydroxy group, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylsulfonyl group having 1 to 6 carbon atoms, and a nitro group Method for producing a polyamide reverse osmosis membrane, characterized in that the benzoic acid substituted with a substituent. According to claim 7, wherein the benzoic acid derivative is 3-hydroxybenzoic acid (4-hydroxybenzoic acid), 4-hydroxybenzoic acid (4-hydroxybenzoic acid), 2,3-dihydroxybenzoic acid (2,3-dihydroxybenzoic acid) , 2,5-dihydroxybenzoic acid, 2,6-dihydroxybenzoic acid, 2-ethoxybenzoic acid, 4- 4-methoxybenzoic acid, 3-methoxybenzoic acid, 4-methoxybenzoic acid, 4-butthoxybenzoic acid, 2,4,5 -Trimethoxybenzoic acid (2,4,5-trimethoxybenzoic acid), 4-fluorobenzoic acid, 5-methyl-2-nitrobenzoic acid, 4- ( Methylsulfonyl) benzoic acid (4- (methylsulfonyl) benzoic acid), 2-sulfobenzoic acid, 2-chlorobenzoic acid, 4-chlorobenzoic acid, 2, 3-dimethylbenzoic acid, 2,4-dimethylbenzoic acid lbenzoic acid), 2,5-dimethylbenzoic acid (2,5-dimethylbenzoic acid), 4-isopropylbenzoic acid (4-isopropylbenzoic acid) is a method for producing a polyamide reverse osmosis membrane, characterized in that selected from the group consisting of. The method of claim 1, wherein the contact of the aliphatic hydrocarbon-based organic solution containing the coated microporous support and the polyfunctional acyl halide is carried out by a dipping or spraying method of the polyamide reverse osmosis membrane Manufacturing method. The method of claim 1, wherein the aliphatic hydrocarbon-based organic solution comprises 0.01 to 1% by weight of at least one polyfunctional acyl halide selected from the group consisting of trimezoyl chloride, isophthaloyl chloride and terephthaloyl chloride. Method for producing a polyamide reverse osmosis membrane to be. A polyamide-based reverse osmosis membrane formed according to any one of claims 1 to 10.