KR20110113994A - Revers osmosis membrane showing high boron rejection - Google Patents

Abstract

The present invention relates to a reverse osmosis membrane having excellent boron removal performance.
The reverse osmosis membrane of the present invention comprises a polyamide layer formed by interfacial polymerization of a porous support, a polyfunctional amine solution, and a polyfunctional acid halogen compound-containing solution containing a specific isophthaloyl chloride substituted with alkoxy. As the alkoxy of isophthaloyl chloride occupies a space without participating in the amide formation, the space between the amides can be narrowed to realize a reverse osmosis membrane having a compact pore size, thereby allowing non-electrolytic organic compounds or non- The removal efficiency of the ionization compound is improved, and in particular, the boron removal rate is excellent, so it is excellent in application as a separation membrane for water treatment.

Description

Reverse osmosis membrane with excellent boron removal performance {REVERS OSMOSIS MEMBRANE SHOWING HIGH BORON REJECTION}

The present invention relates to a reverse osmosis membrane having excellent boron removal performance, wherein a polyfunctional acid halogen compound containing solution containing a porous support and a polyfunctional amine solution and isophthaloyl chloride substituted with C ₁ to C ₃ alkoxy is subjected to interfacial polymerization. It is composed of a polyamide layer formed, and relates to a reverse osmosis membrane having excellent boron removal performance as the pore size in the polyamide layer is densely formed.

The concentration of boron in irrigation water plays an important role in the production and growth of crops, with high concentrations causing yellow spots on plant leaves, accelerating decay, and ultimately ending plant growth. The presence of high concentrations of boron in drinking water can interfere with human reproductive function. Therefore, the European Union (EUOPEAN UNION) regulates the maximum allowable value of boron in drinking water at 1 ppm and the US (WHO) regulates it at 0.5 ppm or less.

Boron generally varies greatly in pH depending on pH. For example, at low pH conditions, most of them are in the form of boric acid (H ₃ BO ₃ ), and they are difficult to be removed (departed) from the membrane because they have a small molecular size and are not charged and have weak electrical repulsion with the surface of the separator. . However, as the pH increases, the ionization proceeds, the molecular size becomes relatively large and becomes negatively charged, thereby removing a large amount of boron due to the electrical repulsion with the negatively charged separator surface.

Equation 1

H ₃ BO ₃ ↔ H ⁺ + H ₂ BO ₃ ^- pKa 9.14

Equation 2

H ₂ BO ₃ ^- ↔ H ⁺ + HBO ₃ ^{2 -} pKa 12.74

Equation 3

HBO ₃ ^{2 -} ↔ H ⁺ + BO ₃ ^{3 -} pKa 13.8

Generally, seawater has a pH of about 7 to 8 and contains 4 to 5 ppm of boron, which is present in the form of boric acid. Specifically, at pH 7, unionized boric acid (H ₃ BO ₃ ) accounts for 99.3%, and at pH 8, 93.2%.

For most seawater desalination, boron removal is 82-86% at pH 8. Applying a 86% removal rate compared to raw water, the concentration of treated water will be over 0.5 ppm, which is above the WHO regulation.

The reverse osmosis membrane used in the normal desalination of seawater was the first starting point in the early 1960s when Loeb and Sourirajan proposed an asymmetric cellulose diacetate membrane. However, while the cellulose diacetate membrane has an advantage of low cost, it has been pointed out that the vulnerable to microorganisms, hydrolysis in the presence of strong bases, and a narrow range of use temperature and pH.

Therefore, as a study for improving these disadvantages, attention has been paid to a separator of a new material, such as polyamide, polyurethane, aromatic polysulfone, aromatic polyamide.

In general, a reverse osmosis membrane or a reverse osmosis composite membrane consists of a support layer for maintaining mechanical strength and an active layer having selective permeability. Recently, a reverse osmosis composite membrane comprising an aromatic polysulfone as a porous support layer and a polyamide as an active layer has been developed and commercialized. It is becoming.

The reverse osmosis composite membrane may be prepared by a thin layer dispersion method, an immersion coating method, a vapor deposition method, a Langmuir-Blodgett method, an interfacial polymerization method, and the most commonly used method is cadette. Interfacial polymerization method [US Pat. No. 4,277,344].

This invention discloses a technique for an aromatic polyamide composite membrane obtained by interfacial polymerization of an aromatic polyfunctional amine containing at least two primary amine substituents and an aromatic acyl halide having at least three acyl halide substituents. In a preferred embodiment, after coating the porous polysulfone support layer with a polyfunctional amine dissolved in water, excess polyfunctional amine solution is removed from the coated porous support, and the coated support is a Freon TF solvent (trichlorotrifluoro Contact with a solution of trimesoylchloride dissolved in roethane). As a result, the polysulfone / polyamide composite membrane showed excellent permeate flow rate and salt rejection ratio, but according to the demand for further improved membrane performance, studies on the increase in permeate flow rate and salt rejection rate of the polyamide reverse osmosis composite membrane were continuously conducted. It is becoming.

As an example, Uemura has suggested another reactant, an aromatic halogen, for the production of crosslinked aromatic polyamide, and the aromatic halogen is represented by the following structure (US Pat. No. 4,761,234).

R ₁₁ to R ₁₆ may be represented by a quick reaction acyl halide group or another substituent, and the number of acyl halide groups is small, usually between 2 and 6, and preferably 2 or 3 are easy to handle. -H, -OCH ₃ , -CH ₃ , -C ₂ H ₅ , -C ₃ H ₇ , -F, -Cl, -Br, and -I, which are substituents other than the acyl halide group forming the above structure, are crosslinked Although not impeded to form a bound polyamide, the substituents theoretically suggest that they are not directly adjacent to the polyamide group, but there are no examples of boron removal rates and no mention of improving boron removal rates.

In addition, Hiroki Tomioka reports that amines other than ammonia can be contacted with a polyamide reverse osmosis membrane to produce a reverse osmosis membrane having a high boron removal rate by interfacial polymerization [US Patent No. 727909]. . However, the reverse osmosis membrane also shows a high salt removal rate and excellent permeation performance in seawater desalination, which is unparalleled. However, non-electrolyte organic compounds such as isopropyl alcohol (IPA) or boron removal rate are still maintained. It does not solve the problem of low.

In the study of the reverse osmosis membrane, a method for improving the boron removal rate is, first, a method of changing the pH, second, a method of changing the pore size.

More specifically, as the pH of the treated water is increased, the removal rate rises vertically. In other words, as the pH is increased boric acid (H ₃ BO ₃₎ borate ttuin a negative charge in the form of (H ₂ BO ₃ ^-) as proceeds in the form of molecular size is relatively larger as, due to the electric repulsive force between the ttuin negatively charged membrane surface increases to be. As a result, an experimental result of completely removing boron at 99% or more at pH 10 and 100% at pH 12 has been published.

However, when the pH of raw water is raised to increase the removal rate of boron, scaling of calcium carbonate and magnesium hydroxide present in seawater becomes severe, and finally, the flow rate of permeate is reduced and the membrane life is shortened. Cause. In addition, there is a disadvantage in that the cost is increased by using a large amount of the buffer solution to lower the pH.

In addition, according to T. Uemura at the 2007 Asian Conference on Desalination & Water Reuse, the pore size of the polyamide layer of the reverse osmosis membrane was measured using molecular design techniques based on mass transfer mechanisms. As a result, the size is 0.56 ~ 0.70nm, the smaller the pore size reports the correlation that the boron removal rate increases, and the method of controlling the pore size to improve the boron removal rate in the reverse osmosis membrane can be one variable It was announced. However, when the separator is manufactured, a method of controlling the pore size is not easy, and the small pore size has a problem of lowering the overall flow rate.

Thus, the inventors of the present invention tried to produce a reverse osmosis membrane having excellent boron removal performance compared to the conventional while ensuring an appropriate flow rate in the reverse osmosis membrane, the polyamide layer formed on the porous support and the porous support, polyamide By tightly controlling the pores of the layer, the present invention has been completed by providing a reverse osmosis membrane having excellent boron removal performance.

An object of the present invention is made of a porous support and a polyamide layer formed on the porous support, the pore of the polyamide layer is tightly controlled to provide a reverse osmosis membrane having excellent boron removal efficiency.

In order to achieve the above object, the present invention provides a porous support and a polyfunctional amine solution of C ₁ ~ C ₃ on the porous support Provided is a reverse osmosis membrane comprising a polyamide layer formed by interfacial polymerization of a polyfunctional acid halogen compound-containing solution including isophthaloyl chloride substituted with alkoxy.

In this case, the polyfunctional amine solution is preferably an aqueous solution containing 0.5 to 10% by weight of meta phenylene diamine.

In addition, the polyfunctional acid halogen compound-containing solution is C ₁ ~ C ₃ Preferably, an alkoxy-substituted isophthaloyl chloride of 0.01 to 2% by weight and trimesoyl chloride of 0.01 to 2% by weight are contained in an aliphatic hydrocarbon solvent, and the solution containing the polyfunctional acid halogen compound is 0.01 to 2 isophthaloyl chloride. It may further contain 2% by weight.

At this time, the C ₁ ~ C ₃ It is preferred that the isophthaloylchloride substituted with alkoxy is 5-methoxy-isophthaloylchloride.

The reverse osmosis membrane of the present invention is a polyamide layer formed by interfacial polymerization of a porous support, a polyfunctional amine solution and a solution containing a polyfunctional acid halogen compound containing a specific isophthaloyl chloride substituted with C ₁ to C ₃ alkoxy. As the alkoxy of isophthaloyl chloride does not participate in the formation of the amide during the interfacial polymerization, the space between the amides is narrowed to realize a reverse osmosis membrane having a compact pore size. Thus, the reverse osmosis membrane of the present invention is improved in the removal efficiency of the non-electrolytic organic compound or non-ionized compound, in particular, excellent boron removal rate is excellent application to the separation membrane for water treatment.

1 is a view showing a schematic structure of MPD-5-methoxy-IPC to which 5-methoxy-1,3-isophthaloyl chloride is applied,
2 is a view showing a schematic structure of MPD-5-methyl-IPC to which 5-methyl-1,3-isophthaloylchloride is applied;
3 is a view showing a schematic structure of MPD-IPC to which isophthaloyl chloride is applied.

Hereinafter, the present invention will be described in more detail.

The present invention is a reverse osmosis membrane comprising a polyamide layer formed by interfacial polymerization of a porous support and a polyfunctional amine solution and a solution containing a specific isophthaloyl chloride substituted with alkoxy of C ₁ to C ₃ . It is about.

As described above, the method for improving the boron removal rate includes a chemical method of changing the pH of the treated water and a physical method of changing the pore size of the separator, the present invention is to control the pore size of the polyamide layer Form.

Specifically, the polyamide layer has been formed the chloride one particular isophthaloyl substituted with a polyfunctional acid halide compound with an alkoxy of C ₁ ~ C ₃ is applied, when the interfacial polymerization is alkoxy of C ₁ ~ C ₃ directly As the space is secured without participating in the chemical reaction, pores are densely formed by narrowing the empty space between the amides, and thus the removal rate of the boron is excellent. In particular, compared to the application of isophthaloyl chloride in which a methyl group is substituted with a polyfunctional acid halogen compound, by alkoxy substitution, the pore size of the membrane can be more compactly realized by narrowing the interval between amides by the size of oxygen atoms.

More specifically, referring to FIGS. 1 and 3, FIG. 1 to which 5-methoxy-1,3-isophthaloylchloride is applied as a polyfunctional acid halogen compound is methoxy compared to FIG. 3 to which a conventional isophthaloyl chloride is applied. With the presence of substituents, it can be seen that the pore size becomes dense by securing a space in the methoxy group in the chemical structure.

The polyfunctional amine solution applicable to the present invention is a polyfunctional amine containing 0.5 to 10% by weight in the aqueous solution, if the content is less than 0.5% by weight is not enough to form the interfacial polymerization does not form a polyamide separator properly There is a problem, if the content exceeds 10% by weight may cause a problem that the permeate flow rate is significantly lowered.

The polyfunctional amine is a polyamine having at least two amine functional groups, more preferably two to three amine functional groups, wherein the amine functional groups are typical primary or secondary amine functional groups, preferably primary amines. It is a functional group.

Preferred examples of the polyamine include aromatic primary diamines such as meta-phenylenediamine and para-phenylenediamine and substituents derived therefrom, and the substituents are alkyl groups such as methoxy groups or ethoxy groups, methoxy Alkoxy groups such as groups or ethoxy groups, hydroxy alkyl groups, hydroxy groups or halogen atoms.

Still other examples of preferred polyamines include alkanediamines such as 1,3-propane diamine and analogs with or without N-alkyl or aryl substituents, cycloaliphatic primary diamines such as cyclohexane diamine, piperazine and alkyl derivatives thereof. Aromatic aliphatic diamines such as cycloaliphatic secondary diamines, N, N'-dimethyl-1,3-phenylenediamine, N, N'-diphenylethylene diamine, benzidine, xylenediamine and derivatives thereof, and the like. .

Particularly preferred polyamines of the invention are aromatic primary diamines, more preferably meta phenylenediamine. At this time, the meta phenylene diamine is preferably contained in an aqueous solution of 0.5 to 10% by weight, preferably 1 to 3% by weight to improve the salt removal rate, it is possible to ensure the salt removal rate of the polyamide separation membrane 99% or more.

In particular, according to the present invention, by applying the optimum amount of meta phenylene diamine as a polyfunctional amine solution, it is difficult to satisfy the conventional salt removal rate and high permeability at the same time, and also sensitively reacts to the change of pH in the manufacturing process of the composite membrane. The problem of the reverse osmosis membrane can be improved.

The polyfunctional acid halogen compound-containing solution applicable to the present invention is a solution in which a polyfunctional acyl halide having a polyfunctional acyl halide substituent is dissolved in an aliphatic hydrocarbon solvent, and isophthal substituted with alkoxy of C ₁ to C ₃ as an acyl halide. It is characterized by containing a monochloride.

More specifically, the solution containing the polyfunctional acid halogen compound is 0.01 to 2% by weight of isophthaloyl chloride and 0.01 to 2% by weight of trimezoyl chloride, more preferably substituted with C ₁ to C ₃ alkoxy in an aliphatic hydrocarbon solvent. Is a form in which 0.04 to 0.3% by weight of isophthaloyl chloride substituted with alkoxy of C ₁ to C ₃ and 0.05 to 0.3% by weight of trimezoyl chloride are dissolved.

At this time, when the content of isophthaloyl chloride substituted with alkoxy of C ₁ to C ₃ is less than 0.01% by weight, too small amount is used, and the pore control effect of the membrane is low. It is unfavorable because it is minute and flow rate performance falls remarkably.

In addition, the trimezoyl chloride is applied to all three substituents participate in the interfacial polymerization reaction to increase the durability of the polyamide separation membrane, if the content is less than 0.01% by weight crosslinking is not made enough when forming polyamide durability There is a problem of falling, and if it exceeds 2% by weight, the polyamide layer is excessively formed, so that there is a problem that the flow rate performance is significantly lowered.

In addition, the polyfunctional acid halogen compound-containing solution may further contain 0.01 to 2% by weight of isophthaloyl chloride, more preferably 0.04 to 0.3% by weight, in consideration of the level of enhancing boron removal rate while maintaining the flow rate performance to the maximum. Can be.

Most preferably, the content of isophthaloyl chloride, trimesoyl chloride and isophthaloyl chloride substituted with alkoxy of C ₁ to C ₃ is 0.01 to 2% by weight of the total polyfunctional acid halogen compound within the above individual contents. Mix to% range.

At this time, the isophthaloyl chloride substituted with alkoxy of C ₁ ~ C ₃ may be applied to the alkoxy ethoxy, methoxy, propoxy, etc., most preferably methoxy-isophthaloyl chloride, especially 5-meth Oxyoxy-1,3-isophthaloylchloride is preferred in terms of pore densification and boron removal efficiency of the polyamide layer.

The aliphatic hydrocarbon solvent may dissolve the total content of the polyfunctional acid halogen compound at 0.01 to 6% by weight, more preferably 0.05 to 0.3% by weight, and chemically bond with the polyfunctional acid halogen compound without participating in the interfacial polymerization reaction. Without this, it is used without particular limitation as long as it does not damage the porous support layer.

Specifically, the aliphatic hydrocarbon solvent may be a mixture of structural isomers of n-alkanes having 5 to 12 carbon atoms and saturated or unsaturated hydrocarbons having 8 carbon atoms, or cyclic hydrocarbons having 5 to 7 carbon atoms.

The porous support used in the present invention is a general microporous support, and the kind thereof is not particularly limited, but in general, the porous support should be large enough to allow permeate to pass therethrough and should not be large enough to prevent crosslinking of the ultra-thin film formed thereon. The pore size of the support is generally 1 to 500 nm, and if it exceeds 500 nm, the ultra-thin film is recessed into the pore size after formation of a thin film, so that the required flat sheet structure cannot be achieved.

Porous supports that can be usefully used in the present invention include polysulfones, polyethersulfones, polyimides, polyamides, polyetherimides, polyacrylonitriles, poly (methyl methacrylates), polyethylene, polypropylenes and polyvinylidene floss And those made of various halogenated polymers such as lides.

Hereinafter, the method for manufacturing the reverse osmosis membrane, specifically, after applying the polyfunctional amine solution on the porous support and removing the excess solution, the porous support coated with the polyfunctional amine solution of C ₁ ~ C ₃ Immediately after contacting with an isophthaloyl chloride-containing polyfunctional acid halogen compound solution substituted with alkoxy to proceed with interfacial polymerization, a separator was formed by interfacial polymerization, and dried at 18 to 50 ° C. for 30 seconds to 3 minutes. It is prepared by immersing for 1 to 30 minutes in a basic aqueous solution of 18 ~ 95 ℃.

Applying the multifunctional amine solution on the porous support may be a method of coating the polyfunctional amine solution on the porous support or immersing the porous support in the multifunctional amine solution, wherein the application time is 0.1 to 10 minutes, Preferably it is carried out for 0.5 to 1 minute.

The polyfunctional amine solution is the same as described above that the polyfunctional amine is dissolved in the aqueous solution, and in particular, the form containing 0.5 to 10% by weight, preferably 1 to 3% by weight of the meta phenylene diamine in the aqueous solution Used.

Contacting the porous support coated with the polyfunctional amine solution to the polyfunctional acid halogen compound solution is crosslinking at a contact interface between the polyfunctional amine solution and the polyfunctional acid halogen compound-containing solution.

In this case, the polyfunctional acid halogen compound-containing solution is the same as described above in the form of a mixed dissolution of isophthaloyl chloride and trimezoyl chloride substituted with C ₁ to C ₃ alkoxy in an aliphatic hydrocarbon solvent.

More specifically, the solution containing the polyfunctional acid halogen compound is 0.01 to 2% by weight of isophthaloyl chloride and 0.01 to 2% by weight of trimezoyl chloride, preferably substituted with C ₁ to C ₃ alkoxy in an aliphatic hydrocarbon solvent. 0.04 to 0.3% by weight of isophthaloyl chloride substituted with alkoxy of C ₁ to C ₃ and 0.05 to 0.3% by weight of trimezoyl chloride are dissolved. In addition, the polyfunctional acid halogen compound-containing solution may further contain 0.01 to 2% by weight, preferably 0.04 to 0.3% by weight of isophthaloyl chloride.

At this time, as an example of the C ₁ ~ C ₃ alkoxy substituted isophthaloyl chloride, methoxy-isophthaloyl chloride, in particular 5-methoxy-1,3-isophthaloyl chloride is a pore densification and boron of the polyamide layer It is preferable in terms of removal efficiency.

After forming the separator by the interfacial polymerization, the separator is dried for 30 seconds to 3 minutes at 18 ~ 50 ℃, to remove impurities or unreacted residue on the surface of the separator, 18 to 95 ℃ to deacyl halide separator Soak for 1 to 30 minutes in aqueous base solution.

At this time, if the drying conditions of the separation membrane is out of the above range, there is a problem that the separation function of the membrane formed undried or over-dried is lowered, and when the membrane is immersed in the base aqueous solution, the temperature of the base aqueous solution is within the above range Deviation is undesirable by affecting the performance of the separator formed for purposes other than deacyl halide purposes.

At this time, the base aqueous solution is not particularly limited, but the use of sodium carbonate solution is preferred.

That is, in the reverse osmosis membrane of the present invention, a polyamide layer is formed by interfacial polymerization of a polyfunctional amine solution and a polyfunctional acid halogen compound solution on a porous support, and isophthal substituted with specific alkoxy as a polyfunctional acid halogen compound. With the application of monochloride, the alkoxy of isophthaloylchloride during interfacial polymerization occupies space without participating in the amide formation, thereby narrowing the spacing between the amides, resulting in a polyamide layer having a small pore size.

Thus, the reverse osmosis membrane of the present invention is densely formed pores in the polyamide layer is excellent in the removal efficiency of the non-electrolytic organic compound or non-ionized compound, in particular, it can implement an improved boron removal efficiency.

At this time, the pore size in the polyamide layer can be seen as correlated with the boron removal rate as described above.

Hereinafter, the present invention will be described in detail with reference to examples.

The following examples are merely illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

< Example  1>

Cast 18% by weight of a solution of dimethylformamide and polysulfone to a thickness of 125 ± 10 μm on a polyester nonwoven fabric, immediately immerse it in distilled water at 25 ° C. for phase change, and wash the nonwoven reinforced polysulfone microporous substrate sufficiently with water. After substituting the solvent and water in the substrate, it was stored in pure water at room temperature. Thereafter, the water layer on the surface was removed by a compression method after immersion for 1 minute in an aqueous solution of metaphenylenediamine having a concentration of 3.0% by weight. The substrate was immersed in an organic solution containing 0.07% by weight of trimezoyl chloride and 0.1% by weight of 5-methoxy-1,3-isophthaloyl chloride for 1 minute, and subjected to interfacial polymerization immediately at room temperature (25 ° C). Immediately after drying for 30 minutes to form a polyamide layer, a reverse osmosis composite membrane was prepared by immersing in 0.2 wt% sodium carbonate solution for 2 hours to remove unreacted residues.

< Example  2>

A reverse osmosis composite membrane was prepared in the same manner as in Example 1, except that an organic solution containing 0.07% by weight of trimezoyl chloride and 0.12% by weight of 5-methoxy-1,3-isophthaloyl chloride was used. Prepared.

< Example  3>

Example 1, except that 0.07% by weight of trimezoyl chloride, 0.07% by weight isophthaloyl chloride, and 0.03% by weight of 5-methoxy-1,3-isophthaloyl chloride were used. In the same manner as in the reverse osmosis composite membrane was prepared.

< Example  4>

Example 1, except that 0.07% by weight of trimezoyl chloride, 0.05% by weight isophthaloyl chloride and 0.05% by weight of 5-methoxy-1,3-isophthaloyl chloride were used. In the same manner as in the reverse osmosis composite membrane was prepared.

< Example  5>

Example 1, except that 0.07% by weight of trimezoyl chloride, 0.03% by weight isophthaloyl chloride, and 0.07% by weight of 5-methoxy-1,3-isophthaloyl chloride were used. In the same manner as in the reverse osmosis composite membrane was prepared.

< Comparative example  1>

A reverse osmosis composite membrane was prepared in the same manner as in Example 1, except that 0.07 wt% of trimezoyl chloride and 0.1 wt% of isophthaloyl chloride were used.

< Comparative example  2>

A reverse osmosis composite membrane was prepared in the same manner as in Example 1, except that an organic solution containing 0.07% by weight of trimezoyl chloride and 0.1% by weight of 5-methyl - 1,3 - isophthaloyl chloride was used. It was.

< Experimental Example >

The performances of the reverse osmosis membranes prepared in Examples 1 to 5 and Comparative Examples 1 to 2 were evaluated, and are shown in Table 1 below.

At this time, the performance of the reverse osmosis membrane was measured at 25 ℃ and 800psi sodium chloride (NaCl) and 5ppm aqueous solution of boron concentration of 32,000ppm, boron concentration was measured using an emission spectrophotometer (ICP emission spectrophotometer). The measurement wavelength range is 400 to 880 nm and the measurement error is within 1 nm.

division    Permeate flow rate ( GFD ) Salt removal rate (%) Boron removal rate (%) Example 1 0.07 wt% TMC, 0.1 wt% MOIPC 18.33 99.33 89.23 Example 2 0.07 wt% TMC, 0.12 wt% MOIPC 17.97 99.31 89.53 Example 3 0.07 wt% TMC, 0.07 wt% IPC,
0.03% by weight MOIPC 19.31 99.25 87.00 Example 4 0.07 wt% TMC, 0.05 wt% IPC,
0.05 wt% MOIPC 18.97 99.26 87.01 Example 5 0.07 wt% TMC, 0.03 wt% IPC,
0.07% by weight MOIPC 18.27 99.30 87.93 Comparative Example 1 0.07 wt% TMC, 0.1 wt% IPC 21.67 99.21 80.92 Comparative Example 2 0.07 wt% TMC, 0.1 wt% MI 19.72 99.24 82.95 TMC: Trimezoyl chloride
IPC: isophthaloyl chloride
MOIPC: 5-methoxy-1,3-isophthaloylchloride
MI: 5-methyl - 1,3 - isophthaloylchloride

As shown in Table 1, the reverse osmosis composite membranes of Examples 1 to 5 to which isophthaloyl chloride substituted with alkoxy as a polyfunctional acid halogen compound exhibited an appropriate level of permeation flow rate and were excellent in boron removal rate of 85% or more. As the content of isophthaloyl chloride substituted with alkoxy was increased within a certain range, it was confirmed that boron removal rate was improved. On the other hand, Comparative Example 1, in which isophthaloyl chloride without a substituent is used as a polyfunctional acid halogen compound, has a low boron removal rate of 80.92%.

As a result of the above, the reverse osmosis membrane of the present invention implements a polyamide layer having a tightly controlled pore size, so that the salt removal rate, the non-electrolytic organic compound and the non-ionizing compound are excellent, and in particular, the boron removal rate is As it is excellent in efficiency, it is useful as a separator for water treatment.

Although the present invention has been described in detail only with respect to the embodiments described, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical scope of the present invention, and such modifications and modifications belong to the appended claims.

Claims (5)

Of the polyfunctional amine solution and C ₁ to C _{3 on} the porous support A reverse osmosis membrane comprising a polyamide layer formed by interfacial polymerization of a solution containing a polyfunctional acid halogen compound containing isophthaloyl chloride substituted with alkoxy. The reverse osmosis membrane according to claim 1, wherein the polyfunctional amine solution is an aqueous solution containing 0.5 to 10 wt% of meta phenylene diamine. The method of claim 1, wherein the polyfunctional acid halogen compound containing solution is C ₁ ~ C ₃ The reverse osmosis membrane, characterized in that 0.01 to 2% by weight of isophthaloyl chloride substituted with alkoxy and 0.01 to 2% by weight of trimezoyl chloride are contained in an aliphatic hydrocarbon solvent. The reverse osmosis membrane according to claim 3, wherein the polyfunctional acid halogen compound-containing solution further contains 0.01 to 2% by weight of isophthaloyl chloride. The reverse osmosis membrane of claim 1, wherein the isophthaloyl chloride substituted with alkoxy is 5-methoxy-isophthaloyl chloride.

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