KR20140073166A - Monovalent ions and divalent ions selective nanofiltration membrane and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a mono- and di-valent ion selective nanofiltration membrane and a manufacturing method thereof, and, more specifically, to a high performance nanofiltration membrane capable of separating mono- and di-valent ions by selectively penetrating mono-valent ions by maintaining the exclusion rate of mono-valent ions low while improving the exclusion rate of di-valent ions. Accordingly, the mono- and di-valent ion selective nanofiltration membrane of the present invention is able to be effectively used in recycling mono-valent ions in dye wastewater generated in a dye process.

Description

TECHNICAL FIELD The present invention relates to an ion selective separating type nanofiltration membrane and a method for preparing the same,

More particularly, the present invention relates to a 1,2-ion selective-separation nano-separator and a method for producing the same. More specifically, the present invention relates to a 1,2- Which can be used for ion recycling.

Generally, the dissociated material can be separated from the solvent using various types of selective membranes. These selective membranes are classified into reverse osmosis membrane (RO), nanofiltration membrane (NF), ultrafiltration membrane (UF), and microfiltration membrane (MF).

Among them, the nanofiltration membrane (NF) is a pressure-driven membrane separation process in which particles smaller than about 2 nm and polymer are blocked, and the pore diameter corresponds to a midpoint between the ultrafiltration membrane UF and the reverse osmosis membrane RO (Having a pore diameter of 1 to 2 nm, a cut-off molecular weight of about 200 to 1,000), and a film having charge on the surface of the film material. That is, in the case of the nanofiltration membrane, the separation effect by the pore (sieve effect), the electrostatic separation effect by the membrane surface charging, and the separation effect by the affinity to the membrane of the water substance are combined, . Unlike the reverse osmosis membrane, which can remove monovalent ions, the nanofiltration membrane freely passes monovalent ions and has a high rejection rate for bivalent ions.

Depending on the material of the nanofiltration membrane, it can be classified into a polyamide-based membrane and a polyvinyl alcohol-based membrane. However, if the molecular weight of the membrane is in the range of 500 to 1,000,

Generally, the polyamide-based separator is prepared by interfacial polymerization of a polyhydric amine such as piperazine or metaphenylenediamine on a microporous support with a polyfunctional acyl halide-based material such as trimesoyl chloride. The polyvinyl alcohol separator has a microporous Is prepared by coating polyvinyl alcohol on a support and crosslinking. The microporous support has a microporous structure and has a pore size sufficient for permeation of permeated water and has an pore size capable of serving as a support in forming a thin film. Examples of the microporous support include various halogenated compounds such as polysulfone, polyisocyanate, polyimide, polyamide, polyetherimide, polyacrylonitrile, polymethyl methacrylate, polyethylene, polypropylene and polyvinylidene fluoride Polymers may be used.

Particularly, in recent years, various researches on polyamide composite membranes have been carried out in order to improve basic properties of membranes such as salt rejection rate, permeation flow rate characteristics, stain resistance and chemical resistance of nano separator.

However, most conventional polyamide nanocomposite membranes are produced using cycloalkylamines such as piperazine instead of aromatic polyamines, which has limitations in separating 1,2-ion. Conventional nanofiltration membranes can lower the elimination rate of monovalent ions, but it is difficult to secure the exclusion rate of some divalent ions such as calcium ions (Ca ²⁺ ) to a certain level or more, (Na ⁺ ) and chlorine ion (Cl ^- ) in the dyeing wastewater.

 Disclosure of the Invention The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a method for producing a solid electrolyte, which is capable of improving the rejection rate of divalent ions while simultaneously maintaining a low rejection rate of monovalent ions, And a method for producing the same.

 In order to solve the above-described problems,

(1) forming a porous support layer by doping a polymer solution on a nonwoven fabric layer; (2) immersing the porous support layer in an aqueous solution containing a polyfunctional amine, and then contacting the porous support layer with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer; And (3) reacting the polyamide layer with a solution containing a monoamine compound to form a coating layer for neutralizing the surface charge. The present invention also provides a method for preparing a 1,2-ion selective separation type nano separator.

According to a preferred embodiment of the present invention, the polymer of step (1) may be selected from the group consisting of a polysulfone polymer, a polyamide polymer, a polyimide polymer, a polyester polymer, an olefin polymer, polyvinylidene fluoride, And ronitril. ≪ RTI ID = 0.0 >

According to another preferred embodiment of the present invention, the monoamine compound of the step (3) includes a primary amine and may have 1 to 6 carbon atoms.

According to another preferred embodiment of the present invention, the monoamine compound may be any one or more selected from the group consisting of methylamine, ethylamine, propylamine, and butylamine. have.

According to another preferred embodiment of the present invention, the monoamine compound-containing solution may contain 0.001 to 10% by weight of a monoamine compound.

According to another preferred embodiment of the present invention, the step (3) may be carried out for 20 seconds to 4 minutes to the solution containing the monoamine compound.

The present invention also relates to a porous support layer; A polyamide layer formed on one surface of the porous support layer; And a coating layer for neutralizing a surface charge formed by bonding a monoamine compound to the surface of the polyamide layer.

According to a preferred embodiment of the present invention, the porous support layer may be formed on the nonwoven fabric layer.

According to another preferred embodiment of the present invention, the porous support layer may be formed of a polysulfone-based polymer, a polyamide-based polymer, a polyimide-based polymer, a polyester-based polymer, an olefin-based polymer, polyvinylidene fluoride and polyacrylonitrile May be any one or more selected from the group consisting of

According to another preferred embodiment of the present invention, the coating layer may be formed by grafting a monoamine compound onto the surface of the polyamide layer.

According to another preferred embodiment of the present invention, the monoamine compound includes a primary amine and may have 1 to 6 carbon atoms.

According to another preferred embodiment of the present invention, the monoamine compound may be at least one selected from the group consisting of methylamine, ethylamine, propylamine, and butylamine. .

According to another preferred embodiment of the present invention, the (-) surface charge of the polyamide layer may be neutralized by 30% or more.

According to a preferred embodiment still another embodiment of the present invention, the monovalent ion is sodium ion (Na ^+), chloride ion (Cl ^-), and the divalent ion is the calcium ion (Ca ^2+), magnesium ion (Mg ^{2 +)} and sulfate ions (SO ₄ ^2-) may be.

According to another preferred embodiment of the present invention, the nanofiber separator comprises 3,200 ppm chlorine ion (Cl ^- ), 1,800 ppm sodium ion (Na ⁺ ), 400 ppm calcium ion (Ca ²⁺ ), 100 ppm magnesium ion (Mg ²⁺ ) and 800ppm of sulfuric acid ion (SO ₄ ^2-) ion-specific rejection rate at which the mixed aqueous solution sikyeoteul transmitted by cross-flow manner (cross-flow mode) at 25 ℃, 75psi pressure conditions, a chlorine ion (Cl ^-) and sodium The ion (Na ⁺ ) is 33% or less, the sulfate ion (SO ₄ ^2- ) is 99% or more, the magnesium ion (Mg ²⁺ ) is 88% or more and the calcium ion (Ca ²⁺ ) is 69% or more.

According to another preferred embodiment of the present invention, the porous support layer may have a thickness of 30 to 300 μm and the polyamide layer may have a thickness of 0.1 to 1 μm.

 In addition, the nanofiber separator according to one preferred embodiment of the present invention is used for monovalent ion recycling treatment in dyeing wastewater.

The 1,2-valent ion-selective separation type nanofiber separator of the present invention enhances the rejection rate of divalent ions while at the same time maintaining the rejection rate of the monovalent ions at a low level to selectively permeate only monovalent ions, Separation may be possible. Therefore, the 1,2-valent ion selective separation type nanocomposite membrane of the present invention can be effectively used for recycling monovalent ions in the dyeing wastewater generated in the dyeing process.

FIG. 1 is a flow chart of the method of manufacturing a nanofiber separator of the present invention.
2 is a cross-sectional view of a nanofiber separator according to a preferred embodiment of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

As described above, the conventional nanofiber separator can lower the elimination rate of monovalent ions, but it is difficult to secure the exclusion rate of some divalent ions such as calcium ions (Ca ²⁺ ) There is a problem that ion separation is limited.

(1) forming a porous support layer by doping a polymer solution on a nonwoven fabric layer; (2) immersing the porous support layer in an aqueous solution containing a polyfunctional amine, and then contacting the porous support layer with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer; And (3) reacting the polyamide layer with a solution containing a monoamine compound to form a coating layer for neutralizing the surface charge, thereby providing a method for producing 1,2-ion selective separation type nano separator. I tried to solve it. As a result, the elimination rate of divalent ions is improved, and at the same time, the elimination rate of monovalent ions is maintained at a low level so that only a monovalent ion is selectively permeated, thereby enabling high-performance 1,2-ion separation. It can be effectively used for recycling monovalent ions in dyeing wastewater.

In the step (1), a polymer solution is doped on the nonwoven fabric layer to form a porous support layer. (S1)

The nonwoven fabric layer is not particularly limited as long as it serves as a support of a membrane, but more preferably synthetic fibers selected from the group consisting of polyester, polypropylene, nylon and polyethylene; Or natural fibers including cellulosic fibers; And the nonwoven fabric layer can control the physical properties of the membrane according to porosity and hydrophilicity of the material. The average pore diameter of the nonwoven fabric layer is preferably 1 to 100 mu m, more preferably 1 to 50 mu m. The thickness of the nonwoven fabric layer of the present invention is preferably 20 to 150 占 퐉. If the thickness is less than 20 占 퐉, the strength and supportability of the entire membrane is insufficient, and if it exceeds 150 占 퐉, the flow rate may be decreased.

The solvent for forming the polymer solution is not particularly limited as long as it can dissolve the polymer uniformly without forming precipitates, but is more preferably selected from the group consisting of N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF) Dimethylsulfoxide (DMSO) or dimethylacetamide (DMAc), or the like.

If the temperature is lower than 20 ° C, the polymer may not be dissolved and the membrane may not be produced. If the temperature is higher than 90 ° C, the viscosity of the polymer solution may become too thin, and thus the membrane may be difficult to produce .

The polymer forming the polymer solution is not particularly limited as long as it is capable of forming a nanometer-separating membrane, but it is more preferably a polysulfone-based polymer including a polysulfone or polyethersulfone, a polyamide-based polymer, a polyimide-based polymer , A polyester-based polymer, an olefin-based polymer such as polypropylene, a polybenzimidazole polymer, polyvinylidene fluoride or polyacrylonitrile, and the like.

The polymer solution may preferably contain 7 to 35% by weight of the polymer. If the content of the polymeric substance is less than 7% by weight, the strength is lowered and the solution viscosity is low. Thus, the film is difficult to manufacture and has a problem. When it exceeds 35% by weight, the concentration of the polymer solution is too high.

In the step (2), the porous support layer is immersed in an aqueous solution containing a polyfunctional amine, and then contacted with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer. (S2)

 Specifically, the polyfunctional amine may be a polyamine having two or three amine functional groups per monomer, and may include a primary amine or a secondary amine. As the polyfunctional amine, an aromatic primary diamine may be used as the metaphenylenediamine, paraphenylenediamine, orthophenyldiamine and a substituent. As another example, aliphatic primary diamine, cyclic aliphatic diamine such as cyclohexenediamine, Cyclic aliphatic secondary amines such as piperazine, primary amines, piperazine, and aromatic secondary amines. More preferably, mephenylenediamine, which is an aromatic primary diamine among the above-mentioned polyfunctional amines, or piperazine, which is a cycloaliphatic secondary diamine, can be used.

 The polyfunctional amine aqueous solution is used in a concentration of 0.1 to 20 wt%, more preferably 0.5 to 8 wt% of a polyamine aqueous solution. The pH of the polyfunctional amine aqueous solution ranges from 7 to 13, and can be adjusted by adding 0.001 to 5% by weight of an acid or base. Examples of such acids and bases include hydroxides, carboxylates, carbonates, borates, phosphates of alkyl metals, trialkylamines, and the like. In addition, a basic acid acceptor capable of neutralizing the acid (HCl) generated during interfacial polymerization may be added to the polyfunctional amine aqueous solution, and a polar solvent, an amine salt, or a polyfunctional tertiary amine may be added as another additive have.

Upon forming the polyamide layer of the present invention, the polyfunctional amine-containing aqueous solution may be applied onto the porous support for 0.1 to 10 minutes, more preferably for 0.5 to 1 minute.

The material that reacts with the polyfunctional amine used in forming the polyamide layer of the present invention is a polyfunctional acid halide, that is, a polyfunctional acyl halide, a polyfunctional sulfonyl halide, a polyfunctional isocyanate, and the like. Preferably, it may be used alone or in a mixed form of trimesoyl chloride, isophthaloyl chloride, terephthaloyl chloride, and the like. At this time, the use of the mixed form is most preferable in terms of the salt removal rate. The polyfunctional acid halide compound is generally used in an amount of 0.005 to 5% by weight (more preferably 0.01 to 0.5% by weight) in an organic solvent which is immiscible with water. Examples of the organic solvent include halogenated hydrocarbons such as Freon, hexane, cyclohexane, heptane, and alkanes having 8 to 12 carbon atoms.

 In the step (3), a solution containing a monoamine compound is reacted with the polyamide layer to form a coating layer for neutralizing the surface charge. (S3)

The coating layer formed in the step (3) may be formed such that the surface charge of the polyamide layer is neutralized and the surface pore size is enlarged by bonding a monoamine compound to the surface of the polyamide layer having a negative charge. The nano-separator having a coating layer formed by neutralizing the surface charge as described above has an excellent rejection rate of divalent ions, especially calcium ions (Ca ²⁺ ) Can be significantly improved and high-performance 1,2-ion separation can be made possible.

The coating layer for neutralizing the surface charge can be prepared by contacting a separation membrane having a polyamide layer formed thereon with a solution containing a monoamine compound to bond a monoamine compound to the surface of the polyamide layer. Monoamine refers to a compound having one nitrogen atom among amines which are compounds in which hydrogen, which is a component of ammonia, is substituted with a hydrocarbon group.

More preferably, the monoamine compound can be grafted to the surface of the polyamide layer to form a coating layer that neutralizes the surface charge. The grafting includes both polymerization and copolymerization of one kind of linear polymer and another kind of polymer.

The solution containing the monoamine compound in the polyamide layer is contacted by impregnation or spraying at a temperature of 25 to 50 DEG C for 5 seconds to 10 minutes, more preferably for 20 seconds to 4 minutes to form a surface charge A coating layer for neutralizing the coating layer can be formed.

At this time, the solution containing the monoamine compound may contain 0.001 to 10% by weight of the monoamine compound. When the amount of the monoamine compound is less than 0.001% by weight, the monoamine compound coating layer may not be formed on the surface of the polyamide layer. If the amount of the monoamine compound is more than 10% by weight, have.

 The monoamine compound of the present invention specifically includes a primary amine and may have 1 to 6 carbon atoms. If the monoamine compound contains a secondary amine in addition to the primary amine, the target removal rate can not be attained. If the monoamine compound contains a tertiary to quaternary amine, the reactivity with the polyamide layer is deteriorated. If the number of carbon atoms is more than 6, there may be a problem that the flow rate is significantly reduced due to strong hydrophobicity.

More preferably, the monoamine compound may be a single compound or a mixture of methylamine, ethylamine, propylamine, and butylamine.

The coating layer thus formed is capable of neutralizing the (-) surface charge of the polyamide layer by 30% or more so that the elimination rate of monovalent ions such as sodium ion (Na ⁺ ) and chlorine ion (Cl ^- ) is maintained at 33% Ions, especially the excretion rate of calcium ions (Ca ²⁺ ), which has been conventionally limited in the improvement of excretion rate, can be remarkably improved to 69% or more, so that 1,2-ion can be effectively separated and sodium ions Na ⁺ ) and chlorine ion (Cl ^- ).

Further, in the prior art, it is limited to control the surface characteristics of the finally prepared separator by introducing an additive into the polyamide layer during the overpolymerization of the polyamide layer. However, in the present invention, a polyamide layer The surface properties can be controlled by reacting the formed nano-separator.

In addition, the present invention manufactured as described above includes a porous support layer; A polyamide layer formed on one surface of the porous support layer; And a coating layer for neutralizing a surface charge formed by bonding a monoamine compound to the surface of the polyamide layer.

 2 is a cross-sectional view of a nanofiber separator according to one preferred embodiment of the present invention. Referring to FIG. 2, the nanofiber separator 200 according to an embodiment of the present invention includes a nonwoven fabric layer 210, A polyamide layer 230 formed on the porous support layer 220 and a coating layer 240 formed on the polyamide layer 230 to neutralize surface charges formed on the porous support layer 220.

The nonwoven fabric layer 210 may be omitted, but the nonwoven fabric layer 210 may be formed as shown in FIG. The nonwoven fabric layer 210 is not particularly limited as long as it serves as a support for the membrane, but more preferably synthetic fibers selected from the group consisting of polyester, polypropylene, nylon and polyethylene; Or natural fibers including cellulosic fibers; And the nonwoven fabric layer can control the physical properties of the membrane according to porosity and hydrophilicity of the material.

The average pore size of the nonwoven fabric layer 210 is preferably 1 to 100 mu m, more preferably 1 to 50 mu m. The thickness of the nonwoven fabric layer 210 of the present invention is preferably in the range of 20 to 150 占 퐉. If the thickness is less than 20 占 퐉, the strength and support of the entire membrane are insufficient, and if it exceeds 150 占 퐉, .

 The porous support layer 220 that can be formed on the nonwoven fabric layer 210 is not particularly limited as long as it can form a nanostructured membrane. However, in order to take mechanical strength into account, it is preferred to use a polymer having a weight average molecular weight in the range of 65,000 to 150,000 Preferable examples thereof include polysulfone-based polymers including polysulfone or polyethersulfone, polyamide-based polymers, polyimide-based polymers, polyester-based polymers, olefin-based polymers such as polypropylene, polybenzimidazole polymers, Polyvinylidene fluoride or polyacrylonitrile, or the like, alone or in combination.

The thickness of the porous support layer 220 may be in the range of 30 to 300 μm. If the thickness is less than 30 μm, there may be a problem of reduction in flow rate and durability due to compaction. If the thickness is more than 300 μm, There may be a problem. The average pore diameter of the porous support layer 220 is preferably 10 to 50 nm.

The polyamide layer 230 formed on the porous support layer 220 may be formed by interfacial polymerization after being immersed in an aqueous solution containing a polyfunctional amine and then contacting an organic solution containing a polyfunctional acid halide compound. The thickness of the polyamide layer 230 may range from 0.1 to 1 μm. If the thickness of the polyamide layer 230 is less than 0.1 μm, the salt removing ability is deteriorated to fail to serve as a selective layer. If the thickness is more than 1 μm, There is a problem that the flow rate is lowered.

The coating layer 240 formed by bonding a monoamine compound to the surface of the polyamide layer 230 has a structure in which a monoamine compound is bonded to the surface of the polyamide layer 230 having a negative charge to neutralize the surface charge, , And the surface pore size can be enlarged. The nanofiber separator having the coating layer 240 formed by neutralizing the surface charge can remarkably improve the elimination rate of divalent ions while maintaining a low removal rate of monovalent ions, thereby enabling high performance 1,2-ion separation. More preferably, the monovalent ion capable of separating high performance as the 1,2-valent ion selective separation type nano separator of the present invention may be sodium ion (Na ⁺ ) and chlorine ion (Cl ^- ), ²⁺ ), magnesium ion (Mg ²⁺ ) and sulfate ion (SO ₄ ^2- ). In particular, the rejection rate of calcium ions (Ca ²⁺ ), which has been conventionally limited in the improvement of the rejection rate, can be significantly improved in the nanofiber separation membrane 200 according to one preferred embodiment of the present invention.

The coating layer 240 for neutralizing the surface charge may be formed by grafting a monoamine compound onto the surface of the polyamide layer 230. The grafting includes both polymerization and copolymerization of one kind of linear polymer and another kind of polymer.

The coating layer 240 formed by grafting a monoamine compound onto the surface of the polyamide layer 230 may neutralize the surface charge of the polyamide layer 230 by 30% or more, Preferably 30 to 40%.

The monoamine compound of the present invention specifically includes a primary amine and may have 1 to 6 carbon atoms. If the monoamine compound contains a secondary amine in addition to the primary amine, the target removal rate can not be attained. If the monoamine compound contains a tertiary to quaternary amine, the reactivity with the polyamide layer is deteriorated. If the number of carbon atoms is more than 6, there may be a problem that the flow rate is significantly reduced due to strong hydrophobicity.

More preferably, the monoamine compound may be a single compound or a mixture of methylamine, ethylamine, propylamine, and butylamine.

The nano-separator 200 is formed by neutralizing at least 30% of the surface charge of the polyamide layer to 3,200 ppm of chlorine ions (Cl ^- ), 1,800 ppm of sodium ions (Na ⁺ ), 400 ppm of calcium ions (Ca ²⁺ ) The removal rate of ions when the aqueous solution containing 100 ppm magnesium ion (Mg ²⁺ ) and 800 ppm sulfate ion (SO ₄ ^2- ) was permeated in a cross-flow mode at 25 ° C and 75 psi pressure, chloride ion (Cl ^-) and sodium ion (Na ⁺⁾ is less than 33% and a sulfate ion (SO ₄ ^2-) of 99% or greater, magnesium ions (Mg ²⁺⁾ is 88% or more, a calcium ion (Ca ²⁺ ) Can be more than 69%.

As described above, the rejection rate of the monovalent ions is maintained at 33% or less, and the rejection rate of the divalent ions, especially calcium ions (Ca ²⁺ ), which has been conventionally limited in improving the rejection rate, is remarkably improved to 69% It is possible to effectively separate the silver ions and effectively use the monovalent ions in the dyeing waste water.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

≪ Example 1 >

A dimethylformamide solution containing 18% by weight of polysulfone was cast on a polyester nonwoven fabric to a thickness of about 125 ± 10 μm, and then immediately immersed in distilled water at 25 ° C. to form a phase. Thereafter, a nonwoven reinforced polysulfone porous substrate Was sufficiently washed with water to replace the solvent and water in the substrate and stored in pure water at room temperature. Thereafter, the sample was immersed in an aqueous solution containing piperazine at a concentration of 1.5% by weight for 40 seconds, and then the surface water layer was removed by a pressing method. The substrate was immersed in an organic solution containing 0.1% by weight of trimesoyl chloride for 1 minute and subjected to interfacial polymerization, followed by natural drying at room temperature (25 DEG C) for 1 minute and 30 seconds to form a polyamide layer.

Immediately after the formation of the polyamide layer, the substrate was immersed in an aqueous solution containing 0.02% by weight of methylamine for 30 seconds, then immersed in a 0.2% by weight sodium carbonate solution for 2 hours to remove unreacted residuals, % Polyamide composite nano filtration membrane having a neutralized coating layer was prepared.

≪ Example 2 >

Was prepared in the same manner as in Example 1, except that the polyamide layer was immersed immediately after the formation of the polyamide layer in an aqueous solution containing 0.02 wt% of ethylamine.

≪ Example 3 >

Was prepared in the same manner as in Example 1, except that the polyamide layer was immersed in an aqueous solution containing 0.02 wt% of propylamine immediately after formation of the polyamide layer.

<Example 4>

The procedure of Example 1 was repeated except that the polyamide layer was immersed immediately after the formation of the polyamide layer in an aqueous solution containing 0.02 wt% of butylamine.

&Lt; Example 5 >

Was prepared in the same manner as in Example 1, except that the polyamide layer was immersed in an aqueous solution containing 0.02 wt% of octylamine immediately after formation of the polyamide layer.

&Lt; Example 6 >

Was prepared in the same manner as in Example 1, except that the polyamide layer was immersed in an aqueous solution containing 0.02 wt% of dimethylamine immediately after formation of the polyamide layer.

&Lt; Comparative Example 1 &

The procedure of Example 1 was repeated except that unreacted residues were removed immediately after the formation of the polyamide layer and then immersing in a monoamine aqueous solution to control the surface charge.

&Lt; Comparative Example 2 &

Was prepared in the same manner as in Example 1, except that the polyamide layer was immersed in an aqueous solution of 0.02% by weight of dimethylaminopropylamine immediately after formation of the polyamide layer.

<Experimental Example>

The nanocomposite membranes prepared according to Examples 1 to 9 and Comparative Examples 1 and 2 were immersed in a solution containing 3,200 ppm chloride ion (Cl ^- ), 1,800 ppm sodium ion (Na ⁺ ), 400 ppm calcium ion (Ca ²⁺ ), 100 ppm magnesium ion ²⁺ ) and 800ppm sulfate ion (SO ₄ ^2- ) in a cross-flow mode at 25 ° C and 75psi pressure to determine initial permeability and salt rejection rate. Respectively. After that, ion rejection rate was measured by ion chromatography.

division Neutralization (%) Flow rate (GFD) Salt exclusion rate (%) Example 1 0.02 wt% methylamine 32.03 17.5 40.00 Example 2 0.02 wt% ethylamine 30.00 19.9 30.48 Example 3 0.02 wt% propylamine 35.56 16.1 41.85 Example 4 0.02 wt% butylamine 39.22 15.9 40.32 Example 5 0.02% by weight of octylamine 32.03 9.0 32.76 Example 6 0.02 wt% dimethylamine 29.41 23.9 26.63 Comparative Example 1 - 0 16.04 24.64 Comparative Example 2 0.02 wt%
Dimethylaminopropylamine -17.65 20.1 31.24

As can be seen from Table 1, the flow rates of Examples 1 to 6 are similar or higher than those of Comparative Example 1, and the salt rejection rate is also high. The salt exclusion rate of the above is measured by TDS (total dissolved solids), and there is a limit to know the exclusion rate of each ion. The rejection rates of the ions were measured by ion chromatography. The results are shown in Table 2.

Coated amine compound Ion removal rate (%) Chlorine ion
(Cl ^-) Sodium ion
(Na ⁺ ) Sulfate ion
(SO ₄ ^2- ) Calcium ion
(Ca ²⁺ ) Magnesium ion
(Mg ²⁺ ) Example 1 0.02 wt% methylamine 30.22 23.52 99.70 71.82 91.27 Example 2 0.02 wt% ethylamine 19.53 15.22 99.56 65.66 88.03 Example 3 0.02 wt% propylamine 33.03 27.31 99.71 69.17 90.00 Example 4 0.02 wt% butylamine 19.95 10.45 100.00 70.55 96.35 Example 5 0.02% by weight of octylamine 22.56 13.62 100.00 70.50 95.50 Example 6 0.02 wt% dimethylamine 14.66 8.19 100.00 65.61 93.12 Comparative Example 1 - 12.01 11.63 97.98 58.11 74.25 Comparative Example 2 0.02 wt% dimethylaminopropylamine 11.77 7.13 99.45 60.76 88.68

As can be seen from the above Table 2, it can be confirmed that the 1,2-ion separation performance is high in Comparative Examples 1 to 2 and Examples 1 to 6.

Specifically, in Examples 1 to 4 using a mono primary amine compound, the rejection rate of chlorine ion and sodium ion was as low as 33% or less, the rejection rate of sulfate ion was 99% or more, the rejection rate of magnesium ion was 88% . In particular, it can be seen that the calcium ion having the lowest rejection ratio in the conventional nanofiber separator has a remarkably improved rejection rate of 69% or more. Therefore, it is confirmed that this is sufficiently usable for the recycling of monovalent ions such as sodium ions and chlorine ions present in the dyeing wastewater.

In Example 5 using a monoamine compound having more than 6 carbon atoms, the flow rate was decreased and the efficiency was lowered. In Example 6 using a secondary monoamine compound and Comparative Example 2 using a diamine compound other than a monoamine compound The excretion rate of chlorine ion and sodium ion was higher than those of Examples 1 to 4, indicating that it is not suitable for use of monovalent ion recycling in dyeing wastewater.

Claims (17)

(1) forming a porous support layer by doping a polymer solution on a nonwoven fabric layer;
(2) immersing the porous support layer in an aqueous solution containing a polyfunctional amine, and then contacting the porous support layer with an organic solution containing a polyfunctional acid halide compound to form a polyamide layer; And
(3) reacting the polyamide layer with a solution containing a monoamine compound to form a coating layer for neutralizing the surface charge. The method according to claim 1,
The polymer of step (1) may be any one selected from the group consisting of a polysulfone-based polymer, a polyamide-based polymer, a polyimide-based polymer, a polyester-based polymer, an olefin-based polymer, polyvinylidene fluoride, and polyacrylonitrile By weight based on the total weight of the nanoparticles. The method according to claim 1,
Wherein the monoamine compound in the step (3) comprises a primary amine and has 1 to 6 carbon atoms. The method of claim 3,
Wherein the monoamine compound is at least one selected from the group consisting of methylamine, ethylamine, propylamine, and butylamine. Gt; The method according to claim 1,
Wherein the solution containing the monoamine compound comprises 0.001 to 10% by weight of a monoamine compound. The method according to claim 1,
Wherein the step (3) comprises contacting the solution containing the monoamine compound for 20 seconds to 4 minutes. A porous support layer;
A polyamide layer formed on one surface of the porous support layer; And
And a coating layer for neutralizing the surface charge formed by bonding the monoamine compound to the surface of the polyamide layer. 8. The method of claim 7,
Wherein the porous support layer is formed on the nonwoven fabric layer. 8. The method of claim 7,
Wherein the porous support layer is at least one selected from the group consisting of a polysulfone-based polymer, a polyamide-based polymer, a polyimide-based polymer, a polyester-based polymer, an olefin-based polymer, polyvinylidene fluoride, and polyacrylonitrile Selective separable nanoparticles. 8. The method of claim 7,
Wherein the coating layer is formed by grafting a monoamine compound onto the surface of the polyamide layer. 8. The method of claim 7,
Wherein the monoamine compound comprises a primary amine and has 1 to 6 carbon atoms. 8. The method of claim 7,
Wherein the monoamine compound is at least one selected from the group consisting of methylamine, ethylamine, propylamine, and butylamine. 8. The method of claim 7,
Wherein the nano-separator is characterized in that the (-) surface charge of the polyamide layer is at least 30% neutralized. 8. The method of claim 7,
The monovalent ion is sodium ion (Na ^+), chloride ion (Cl ^-), and the divalent ion is the calcium ion (Ca ^2+), magnesium ion (Mg ²⁺⁾ and a sulphate ion (SO ₄ ^2-) of Wherein the first and second ion-selective separation type nanocomposite membranes are separated from each other. 8. The method of claim 7,
The nano-membrane 3,200ppm chlorine ion (Cl ^-), 1,800ppm sodium ion (Na ^+), 400ppm of calcium ions (Ca ^2+), 100ppm of magnesium ion (Mg ^2+), and 800ppm of sulfuric acid ion (SO ₄ ^2-) is When the mixed aqueous solution was permeated in a cross-flow mode at a pressure of 75 psi at 25 ° C, the ion removal rate was 33% or less for chlorine ions (Cl ^- ) and sodium ions (Na ⁺ ), Wherein the sulfate ion (SO ₄ ^2- ) is 99% or more, the magnesium ion (Mg ²⁺ ) is 88% or more, and the calcium ion (Ca ²⁺ ) is 69% or more. 8. The method of claim 7,
Wherein the porous support layer has a thickness of 30 to 300 占 퐉 and the polyamide layer has a thickness of 0.1 to 1 占 퐉. A 1,2-ion selective detachment type nanocomposite membrane according to any one of claims 7 to 16, characterized in that the nanocomposite membrane is used for monovalent ion recycling treatment in dyeing wastewater.

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