KR20170096692A

KR20170096692A - Forward osmosis membrane and production method thereof

Info

Publication number: KR20170096692A
Application number: KR1020160018221A
Authority: KR
Inventors: 이기형; 김상범; 최정환
Original assignee: 주식회사 마이크로필터
Priority date: 2016-02-17
Filing date: 2016-02-17
Publication date: 2017-08-25
Also published as: KR101781473B1

Abstract

The present invention relates to a positive osmosis membrane and a method of manufacturing the same, comprising the steps of: (A) providing a monofilament mesh having a constant lattice; (B) dissolving a polymer in a polar aprotic solvent and then defoaming the polymer to prepare a polymer solution in the absence of microbubbles; (C) pouring and fixing the mesh, and then pouring the polymer solution into the mesh and casting to a predetermined thickness; (D) inducing the phase transition by immersing the polymerized solution into the water to complete the porous support having the porous membrane; (E) washing and drying the completed porous support; (F) drawing and drying a dried porous support, then pouring a multifunctional amine-based aqueous solution, and pouring a polyfunctional acid halide-based organic solution onto the porous support to induce interfacial polymerization therebetween to produce a polyamide membrane; (G) crosslinking the result of step (F) at a temperature of 70 to 95 DEG C for 3 to 10 minutes to form a polyamide activation layer.
The osmosis membrane according to the present invention can be used for removing water from a high concentration solution, radioactive waste, high turbidity solution and the like which have been conventionally difficult to concentrate with an RO membrane, and can be industrially used in a wide range such as seawater desalination.

Description

TECHNICAL FIELD [0001] The present invention relates to a positive osmosis membrane,

The present invention relates to a quasi-osmosis membrane for separating water from raw water by using a positive osmosis phenomenon and a method of manufacturing the same, and more particularly, to a quasi-osmosis membrane that constitutes and manufactures a quasi-osmosis membrane using a mesh- And a manufacturing method thereof.

In general, forward osmosis refers to a phenomenon in which water moves from a low concentration solution to a high concentration solution due to a difference in concentration between two solutions. The pressure generated at this time is referred to as osmotic pressure, and this osmotic pressure is used as a driving force The membrane separation is referred to as a normal osmosis membrane.

This is in contrast to reverse osmosis membranes, which are often used for ultra pure water or seawater desalination.

In order to separate the water from the raw water, the induction solution is used. In this case, the induction solution should have a higher salt concentration than the raw water to be separated, thereby allowing the water to move from the raw water to the induction solution.

In order to minimize the permeation resistance of the positive osmosis membrane, cellulose triacetate is used as a hydrophilic material. On the support layer having a thickness of 25 to 75 μm, the same material as that of the support layer By coating a selective layer having a thickness of 8 to 18 占 퐉.

However, the above-described cellulose triacetate-based pure osmosis membrane has a disadvantage that the pH range that can be used is extremely limited.

In addition, since it exhibits weak characteristics to acids and alkalis, the active layer is damaged if it is outside the appropriate pH range of 4 to 8, and reverse salt flux due to damage of the active layer may increase.

In addition, since cellulose is a biodegradable substance, it is vulnerable to attack by microorganisms, and the usable temperature range is narrowed from 0 to 35 degrees Celsius.

In addition, International Publication WO / 2008-137082 discloses a process for producing a UF-level film by casting a polysulfone solution on a nonwoven fabric, and interfacially polymerizing a polyfunctional amine and a polyfunctional acyl halide on the surface of the film to obtain an active layer And proposes and discloses a configuration.

However, the above-described technique is essentially a pure osmosis membrane having a similar structure to a reverse osmosis membrane, and it is difficult to expect a high flow rate in the osmosis.

In summary, the osmosis membrane should exhibit different characteristics from the conventional reverse osmosis membrane, as follows.

First, since there is no artificial pressure, the thickness should be as thin as possible to increase the permeate flux.

Second, it should exhibit a low salt flux (reverse salt flux). This means that the salt of the inducing solution should not diffuse into the raw water.

Third, the porosity of the inner support layer of the osmosis membrane should be high and the porosity should have a small degree of tortuosity in order to minimize the internal concentration in the membrane.

Korean Patent No. 10-1448017

Disclosure of the Invention The present invention has been conceived in view of the above problems and the like, and it is an object of the present invention to provide a method and apparatus for constructing and manufacturing a positive osmosis membrane using a mesh- And then coating the polyamide-activated layer on one side of the support to complete the osmosis membrane, and a method of manufacturing the same.

The present invention can be utilized as a solution for removing water from high concentration solutions or radioactive waste high turbidity solutions which have been conventionally difficult to concentrate with reverse osmosis (RO) membranes. In addition, And to provide a method of manufacturing the same.

It is an object of the present invention to provide a process for producing a polytetrafluoroethylene membrane, which can operate at a wide pH range and can exhibit more stable characteristics against attack of microorganisms.

In order to accomplish the above object, according to the present invention, there is provided a quasi-osmosis membrane comprising a polymer layer 112 formed by casting a polymer solution on a mesh 111 made of monofilaments and having a predetermined lattice, A porous support (110) comprising; The porous support 110 is coated with a polyfunctional amine halide-based organic solution while the polyfunctional amine-based aqueous solution is added to the porous support 110 to induce interfacial polymerization between them, And a polyamide activation layer (120) formed by crosslinking and activating the membrane after formation of the membrane, wherein the mesh (111) composed of the monofilaments is one of polypropylene, polyamide, polyethylene terephthalate, nylon, And is characterized by satisfying the conditions of a diameter of 20 to 70 μm, an aperture ratio of 10 to 50%, and a transmittance of 10 to 35 cm 3 / m 2.

Here, the polymer solution for forming the polymer layer 112 of the porous support 110 may be any one selected from polysulfone, polyethersulfone, and polyacrylonitrile, Is dissolved in any one polar aprotic solvent selected from NMP, dimethylformamide (DMF), hexamethylphosphoric triamide (HMPA), acetone nitrile (ACN) and dimethylsulfoxide (DMSO).

Here, the multifunctional amine-based aqueous solution for the polyamide activation layer 120 may be prepared by using an aqueous solution in which any one selected from the group consisting of metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, and piperazine is dissolved; The organic solution containing the polyfunctional acid halide compound for the polyamide activation layer 120 may be any one selected from the group consisting of trimesoyl chloride, isophthaloyl chloride, and terephthaloyl chloride, .

According to another aspect of the present invention, there is provided a method for manufacturing a quasi-osmotic membrane, comprising the steps of: (A) providing a mesh comprising a monofilament and having a predetermined lattice as a base; (B) dissolving a polymer in a polar aprotic solvent at a concentration of 10 to 25 wt%, and defoaming the polymer in a vacuum to prepare a polymer solution in the absence of microbubbles; (C) pouring the polymer solution into a mesh and casting to a predetermined thickness after unfolding and fixing the mesh in a tight state without wrinkles; (D) inducing phase transformation by immersing the cast mesh in water to form a porous membrane having a porous membrane Completing the support; (E) washing and drying the completed porous support; (F) introducing a multifunctional amine-based aqueous solution into the dried porous support by unfolding and fixing, and then pouring and contacting the multifunctional acid halide-based organic solution onto the porous support to induce interfacial polymerization therebetween to produce a polyamide membrane; (G) crosslinking the result of step (F) at a temperature of 70 to 95 DEG C for 3 to 10 minutes to form a polyamide activation layer.

Here, in the step (A), the mesh made of the monofilament is made of any one material selected from among polypropylene, polyamide, polyethylene terephthalate, nylon, and polyester, and has a diameter of 20 to 70 mu m, 50% and a transmittance of 10 to 35 cm < 3 > / m < 2 >.

Here, in the step (B), the polymer solution may be any one selected from polysulfone, polyethersulfone, and polyacrylonitrile, and may be selected from the group consisting of ene-methylpyrrolidone, dimethylformamide, hexamethyl Is dissolved in any one polar aprotic solvent selected from the group consisting of phosphoric triamide, acetone nitrile and dimethyl sulfoxide; In the step (F), the polyfunctional amine-based aqueous solution may be prepared by using an aqueous solution in which any one selected from the group consisting of metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, and piperazine is dissolved and the polyfunctional acid halide- Is characterized in that any one selected from the group consisting of trimesoyl chloride, isophthaloyl chloride and terephthaloyl chloride is used, and is dissolved in an isoparaffin-based solvent.

According to the present invention, it is possible to use water as a solution for removing water from high concentration solutions or radioactive wastes having high turbidity, which have been conventionally difficult to concentrate with reverse osmosis (RO) membranes. In addition, It is possible to provide a positive osmosis membrane that can broaden the range of application,

The present invention can provide a positive osmosis membrane that can operate at a wide pH range and can exhibit more stable characteristics against attack of microorganisms.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing a hydroentangling membrane according to an embodiment of the present invention; FIG.
2 is a photograph showing a monofilament mesh which is a base material for a positive osmosis membrane in the present invention.
FIG. 3 is a photograph showing a state in which a polymer solution is cast on the monofilament mesh of FIG. 2;
4 is an electron micrograph showing a porous support in the present invention.
FIG. 5 is an electron microscope photograph showing a pure osmosis membrane completed by forming an activation layer on a porous support according to the present invention.
6 is an electron micrograph showing an enlarged state of FIG.
FIG. 7 is a flow chart illustrating a method of fabricating a normal osmosis membrane according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.

1 to 6, the osmosis membrane 100 according to an embodiment of the present invention includes a mesh 111 made of monofilaments having a certain lattice as a base, and a polymer solution is applied to the mesh 111 And a porous support 110 having a polymer layer 112 formed by casting.

The mesh 111 made of the monofilament may be made of any one material selected from polypropylene (PP), polyamide (PA), polyethylene terephthalate (PET), nylon, and polyester.

At this time, it is preferable that the meshes 111 made of the monofilaments have a regular square shape with a lattice structure, and the ratio of the open area in the entire projected area, that is, the open area ratio of at least 10% is preferably used.

Here, the mesh 111 made of the monofilaments preferably has a diameter of 20 to 70 μm, an aperture ratio of 10 to 50%, and a transmittance of 10 to 35 cm 3 / m 2.

If the diameter, the aperture ratio, and the transmittance are less than the above-mentioned minimum conditions, the permeation flow rate may be drastically reduced due to the film formation of a dense structure. If the film thickness is larger than the maximum condition described above, The flow rate is large but the removal rate of the membrane is greatly decreased.

The polymer solution for forming the polymer layer 112 of the porous support 110 may be any one selected from polysulfone, polyethersulfone, and polyacrylonitrile, which is dissolved in a polar aprotic solvent. desirable.

Wherein the polar aprotic solvent is selected from the group consisting of N-methylpyrrolidone (NMP), dimethylformamide (DMF), hexamethylphosphoric triamide (HMPA), acetone nitrile (ACN), dimethylsulfoxide Any one species can be used.

The porous support 110 may be formed by casting a polymer solution into the mesh 111 and immersing it in water to induce phase transition of the polymer solution to convert it into a UF-grade porous membrane, thereby forming the polymer layer 112 And the mesh 111 serves as a support for maintaining a physical strength with respect to the polymer layer 112 of the porous membrane.

Further, the porous support 110 is coated, and a multifunctional acid halide-based organic solution is added to the porous support 110 in the presence of a multifunctional amine-based aqueous solution, thereby bringing them into contact with each other, And a polyamide activation layer 120 that is activated by crosslinking after a polyamide film is formed.

The polyfunctional amine-based aqueous solution for the polyamide activation layer 120 is preferably an aqueous solution in which any one selected from the group consisting of metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, and piperazine is dissolved.

The organic solution containing the polyfunctional acid halide compound for the polyamide activation layer 120 may be any one selected from the group consisting of trimesoyl chloride, isophthaloyl chloride, and terephthaloyl chloride, .

The method of manufacturing the osmosis membrane according to the present invention having the above-described structure will be described with reference to FIG.

A mesh having a certain lattice made of monofilaments is provided as a substrate (S10).

At this time, the mesh made of the monofilament is made of any one material selected from among polypropylene, polyamide, polyethylene terephthalate, nylon and polyester, and has a lattice structure having a regular shape of square, It is preferable to use the ratio of the open area, that is, the opening ratio of at least 10%.

Here, it is more preferable that the mesh satisfies the conditions of a diameter of 20 to 70 μm, an aperture ratio of 10 to 50% and a transmittance of 10 to 35 cm 3 / m 2.

The polymer is dissolved in a polar aprotic solvent at a concentration of 10 to 25 wt%, and then defoamed in a vacuum to prepare a polymer solution in the absence of micro-bubbles (S20).

At this time, any one selected from polysulfone, polyethersulfone, and polyacrylonitrile may be used as the polymer used in the polymer solution, and the polar aprotic solvent used in the polymer solution may be en-methylpyrrolidone ( NMP), dimethylformamide (DMF), hexamethylphosphoric triamide (HMPA), acetone nitrile (ACN), and dimethylsulfoxide (DMSO).

Here, in order to dissolve the polymer, it is necessary to have strong attractiveness to the polymer, and the polar solvents listed above are used for this purpose.

The mesh is spread on a plate such as a glass plate in a tight state without wrinkles. The polymer solution in which the polymer is dissolved in the polar aprotic solvent is poured into a mesh and cast to a certain thickness using a blade (S30).

Here, the casting thickness of the polymer solution is preferably 60 to 100 占 퐉 including the meshes, and it is possible to exhibit optimum physical properties such as optimum permeation flow rate and removal rate.

Here, when the thickness is smaller than the minimum thickness, the physical properties of the removal rate are lowered, and when the thickness is thicker than the maximum thickness, the physical properties of the permeation flow rate are lowered.

The casting of the polymer solution is immediately dipped in the water to induce the phase transition of the polymer solution to complete the porous support having the porous membrane (S40).

The finished porous support having the porous membrane is washed several times with washing water, and dried (S50).

At this time, drying is preferably natural drying, and a method using heat or wind may be used.

After washing and drying, the dried porous support is spread and fixed to a plate such as a glass plate, then a multifunctional amine-based aqueous solution is poured thereon, and a multifunctional acid halide-based organic solution is poured thereon to bring them into contact with each other. Amide film is formed (S60).

At this time, the polyfunctional amine-based aqueous solution may be an aqueous solution in which any one selected from the group consisting of metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, and piperazine is dissolved.

The polyfunctional amine-based aqueous solution is preferably a solution obtained by dissolving a polyfunctional amine-based material at a concentration of 1 to 20 wt% with a solvent as a water, and when the solution is dissolved at a concentration of 2 to 10 wt%, an optimal permeation flow rate and a removal rate characteristic .

The organic solution containing the polyfunctional acid halide compound may be any one selected from the group consisting of trimesoyl chloride, isophthaloyl chloride and terephthaloyl chloride, which is dissolved in an isoparaffin-based solvent.

The polyfunctional acid halide compound is preferably used in an amount of 0.1 to 1 wt% in an isoparaffin-based solvent, and it is possible to optimize the thin film formation through compound formation through reaction with an amine-based material.

At this time, when the polyfunctional acid halide is dissolved in the amount of 0.1 to 0.5 wt%, the optimum permeation flow rate and removal efficiency can be exhibited.

Here, after cleaning and drying, the porous support is spread and fixed to a plate such as a glass plate, and a polyfunctional amine-based aqueous solution is poured into the porous support. Then, the excess polyfunctional amine-based aqueous solution is removed using a nip roll.

Then, a polyfunctional acid halide-based organic solution is poured thereon and brought into contact with a polyfunctional amine-based aqueous solution to produce a polyamide film by interfacial polymerization.

The resulting polyamide film is then placed in an oven having a closed space, and is crosslinked at a temperature of 70 to 95 ° C. for 3 to 10 minutes to form a polyamide activation layer by activating the resulting polyamide membrane on the porous support (S 70) .

Here, the conditions having the above-described temperature and time categories are intended to induce an optimal crosslinking reaction between the polyfunctional amine-based material and the polyfunctional halogen compound.

Accordingly, the present invention can be utilized as a solution for removing water from a solution of high concentration or radioactive waste having a high turbidity, which has been conventionally difficult to concentrate with a reverse osmosis (RO) membrane, it is possible not only to operate in a pH range but also to exhibit more stable characteristics against attack of microorganisms. In addition, it can be used for seawater desalination and the like, and thus it is possible to produce a membrane having a wide range of applications.

Hereinafter, examples and experimental examples of a purified osmosis membrane produced according to the present invention will be described.

A monofilament mesh having a diameter of 35 μm, an aperture ratio of 23% and a transmittance of 15 cm 3 / m 2 was prepared and dissolved in 15 wt% of polysulfone in N-methyl 2-pyrrolidone (NMP) And the polymer solution is defoamed in a vacuum to prepare a dope solution in the absence of fine bubbles.

The mesh is spread on a glass plate in a tight state without wrinkles, and then an aqueous solution containing polysulfone dissolved in the mesh is poured. The polysulfone aqueous solution is cast using a blade and cast to a thickness of 100 μm with a mesh.

The meshes cast with the polysulfone aqueous solution are immediately immersed in water to induce the phase transition of the polysulfone aqueous solution, thereby completing the porous support having the porous membrane.

The porous support having the porous membrane is washed several times with pure water, and then dried to remove water.

After the dried porous support is fixed on a glass plate, an aqueous solution in which 10 wt% of metaphenylenediamine is dissolved in water is poured, and an excess of the aqueous solution of m-phenylenediamine is removed using a nip roll.

A polyamide film is formed by interfacial polymerization by pouring an aqueous solution of trimesoyl chloride in which 0.5 mol% of triphenyloyl chloride is dissolved in an isoparaffin-based solvent, over an aqueous metaphenylenediamine solution.

The resulting polyamide film was placed in an oven and crosslinked at a temperature of 90 ° C for 5 minutes to activate the polyamide membrane to produce a polyamido activated membrane having a polyamide activated layer.

The flux was measured using the weight change of the induction solution with time, and the change in the conductivity on the side of the raw water was measured, reverse salt flux) were measured.

At this time, 1 M NaCl was used as the induction solution and ultrapure water was used as the raw water.

As a result, the flux of the purified osmosis membrane manufactured according to the present invention was 25 ~ 30 LMH (liter / sq.mh) and the reverse salt diffusion was 0.1 ~ 0.15 (sq.mh).

These experimental results show that the permeability of the pure osmosis membrane distributed on the market is high 18 ~ 20 LMH (liter / sq.mh), which indicates a high flux, and has excellent physical properties as a water treatment separator Can be confirmed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the present invention as defined by the appended claims. Variations will fall within the technical scope of the present invention.

100: osmosis membrane 110: porous support
111: mesh 112: polymer layer
120: polyamide activated layer

Claims

A porous support (110) comprising a polymer layer (112) made of monofilaments and made of a mesh (111) having a certain lattice as a base and casting a polymer solution into the mesh (111);
The porous support 110 is coated with a polyfunctional amine halide-based organic solution while the polyfunctional amine-based aqueous solution is added to the porous support 110 to induce interfacial polymerization between them, A polyamide activation layer 120 that is activated by crosslinking after formation of a film; , &Lt; / RTI >
The mesh 111 made of the monofilaments is made of any one material selected from polypropylene, polyamide, polyethylene terephthalate, nylon and polyester,
The opening ratio of 10 to 50% and the permeability of 10 to 35 cm < 3 > / m < 2 >.

The method according to claim 1,
The polymer solution forming the polymer layer 112 of the porous support 110 may be,
(NMP), dimethylformamide (DMF), hexamethylphosphoric triamide (HMPA), acetone (NMP), or the like, using any one kind of polymer selected from polysulfone, polyether sulfone and polyacrylonitrile. Nitrile (ACN), and dimethylsulfoxide (DMSO) in a polar aprotic solvent.

The method according to claim 1,
The polyfunctional amine-based aqueous solution for the polyamide activation layer (120)
An aqueous solution in which any one selected from the group consisting of metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, and piperazine is used;
The organic solution containing the polyfunctional acid halide compound for the polyamide activation layer (120)
Wherein the water-soluble polymer is dissolved in an isoparaffin-based solvent using any one selected from the group consisting of trimethoyl chloride, isophthaloyl chloride and terephthaloyl chloride.

(A) providing a mesh comprising a monofilament having a constant lattice as a substrate;
(B) dissolving a polymer in a polar aprotic solvent at a concentration of 10 to 25 wt% and defoaming in a vacuum to prepare a polymer solution in the absence of microbubbles;
(C) unfolding and fixing the mesh in a tight state without wrinkles, then pouring the polymer solution into a mesh and casting to a certain thickness:
(D) inducing a phase transition by immersing the cast mesh in water to complete a porous support having a porous membrane;
(E) washing and drying the completed porous support;
(F) introducing a multifunctional amine-based aqueous solution into the dried porous support by unfolding and fixing, and then pouring and contacting the multifunctional acid halide-based organic solution onto the porous support to induce interfacial polymerization therebetween to produce a polyamide membrane;
(G) crosslinking the result of step (F) at a temperature of 70 to 95 DEG C for 3 to 10 minutes to form a polyamide activation layer; &Lt; / RTI >

5. The method of claim 4,
In the step (A), the mesh comprising the monofilaments may be any one selected from the group consisting of polypropylene, polyamide, polyethylene terephthalate, nylon, and polyester,
Wherein the monofilament mesh has a diameter of 20 to 70 占 퐉, an aperture ratio of 10 to 50%, and a permeability of 10 to 35 cm3 / m2.

5. The method of claim 4,
In the step (B), the polymer solution may be any one selected from polysulfone, polyethersulfone, and polyacrylonitrile, and may be selected from the group consisting of n-methylpyrrolidone, dimethylformamide, hexamethylphosphoric tri Amide, acetone nitrile and dimethyl sulfoxide in a polar aprotic solvent;
In the step (F), the aqueous polyfunctional amine solution is prepared by dissolving any one selected from the group consisting of metaphenyldiamine, paraphenyldiamine, orthophenyldiamine, and piperazine,
Wherein the organic solution containing the polyfunctional acid halide compound is one selected from the group consisting of trimethoyl chloride, isophthaloyl chloride and terephthaloyl chloride, which is dissolved in an isoparaffin-based solvent. Gt;