KR20090099635A - A hybrid membrane manufacturing method mixed organic and inorganic matter and membrane manufactured by its method - Google Patents

Abstract

A manufacturing method of an organic and inorganic complex hollow membrane in which a supporter is reinforced and the hollow membrane manufactured thereby are provided to improve structural stability and mechanical strength, and to offer excellent permeability. A manufacturing method of an organic and inorganic complex hollow membrane in which a supporter is reinforced includes the following steps of: manufacturing an organic polymer solution used for deforming structure of the membrane easily, and forming a wide effective area of the membrane; manufacturing an inorganic solution having excellent chemical resistance; forming the hollow membrane by applying the organic polymer solution and the inorganic solution on the supporter; and removing an organic solvent by dipping the supporter in distilled water.

Description

A hybrid membrane manufacturing method mixed organic and inorganic matter and membrane manufactured by it's method

The present invention is a polyvinylidene fluoride cohexafluoropropylene (poly (vinylidene fluoride-co-hexafluoropropylene), PVDF-HFP), an organic copolymer (tetraethoxysilane, TEOS) by the phase transition method ) Is applied to the support with a film forming solution prepared by mixing) to produce a hollow fiber membrane, the hollow fiber membrane prepared by the film forming solution is capable of controlling the pore size and distribution formed in the hollow fiber membrane, the particles contained in the solution to be treated It is configured to selectively use hollow fiber membrane according to the size, can be applied to various water treatment processes, excellent mechanical strength, excellent physical and chemical durability, excellent permeability, and functional organic and inorganic hybrid polymer hollow fiber membrane manufacturing method And it relates to a hollow fiber membrane produced by the production method.

Conventional separators are largely classified into inorganic membranes and organic polymer membranes, while inorganic separators have excellent chemical resistance and can be applied at high temperatures, but require high production costs, physical strength is weak, and effective membrane area is relatively small. On the other hand, since organic polymer membranes require less production cost, have a large effective area of membrane, and are easy to manufacture by freely modifying the structure of the membrane, membranes using many kinds of polymers have been developed.

Up to now, hollow fiber membranes have been produced by polytetrafluoroethylene, polypropylene, polysulfone, polyvinylidenedifluoride and the like by a phase transfer method or melt spinning method. It is very sensitive and has a low physical strength.

In addition, the hollow fiber membranes thus far are limited to application areas separated by particle size, and not only improve the physical and chemical properties of the hollow fiber membranes, but also pore sizes and pore distributions (porosity) that can satisfy the permeation characteristics appropriate to the processing purposes. The manufacturing method that can control) is not developed.

The problem to be solved by the present invention is to reinforce the support having excellent physical and chemical durability and control the pore size according to the application purpose by mixing the organic polymer and the inorganic material for the production of hollow fiber membrane having the advantages of both inorganic membrane and organic polymer membrane To provide a functional organic and inorganic hybrid polymer hollow fiber membrane production method and a hollow fiber membrane prepared by the method.

A more specific problem to be solved by the present invention is to form a lattice structure on the surface of the membrane by mixing and reacting an organic copolymer (organic polymer) with an excellent physical and chemical stability and the organic material and inorganic material to increase the structural stability of the hollow fiber membrane and mechanical Not only to increase the strength but also to achieve a hollow fiber membrane having excellent permeability.

A specific solution of the present invention is a method for producing a polyvinylidene fluoride cohexafluoropropylene hollow fiber membrane, 10% to 30% by weight of polyvinylidene fluoride cohexafluoropropylene 90% by weight to dimethylacetamide After dissolving in 70% by weight to prepare an organic polymer solution, the prepared organic polymer solution is sprayed with a spray nozzle and applied to the surface of the support to form a hollow fiber membrane, the formed used desert film in distilled water for 24 hours It is to provide a polyvinylidene fluoride cohexafluoropropylene hollow fiber membrane through the step of immersing to completely remove the remaining organic solvent.

Another solution of the present invention is a method for preparing a polyvinylidene fluoride cohexafluoropropylene and a tetraethoxysilane hybrid hollow fiber membrane, wherein the tetraethoxysilane is 30 vol% to 50 vol% at room temperature, After dissolving 70% to 50% by volume of ethanol, 3 to 5 times distilled water and 0.05 to 0.2 times hydrochloric acid of the dissolved solution were uniformly mixed in a molar concentration ratio to prepare an inorganic solution. Dissolving 10% to 30% by weight of lycocofluorofluoropropylene in 90% to 70% by weight of dimethylacetamide to prepare an organic polymer solution, the organic polymer solution is 40% to 60% by weight, After mixing the tetraethoxysilane inorganic solution at 60 wt% to 40 wt% for 12 hours to prepare an organic and inorganic hybrid solution, the prepared mixed solution To the surface of the support to form a hybrid hollow fiber membrane, and then the formed hybrid hollow fiber membrane is immersed in distilled water for 24 hours to completely remove the remaining organic solvent, thereby removing polyvinylidene fluoride cohexafluoro. To provide a propylene and tetraethoxysilane hybrid hollow fiber membrane.

The present invention is excellent in physical and chemical durability by mixing organic polymers and inorganic materials for the production of hollow fiber membranes having both the advantages of inorganic membranes and organic polymer membranes by the method of manufacturing functional organic and inorganic hybrid polymer hollow fiber membranes There is an effect of providing an excellent hollow fiber membrane reinforced with a support that can control the pore size according to the application purpose.

Another effect of the present invention is to form a lattice structure on the surface of the membrane by mixing the organic copolymer (organic polymer) and the organic polymer and inorganic material with better physical and chemical stability to increase the structural stability of the hollow fiber membrane and increase the mechanical strength In addition to achieving a hollow fiber membrane excellent in permeation characteristics.

It looks at the specific content for the practice of the present invention. The present invention is a solution of 30 to 50% by volume of tetraethoxysilane at room temperature, 70 to 50% by volume of ethanol to form a solution, and the composition of the solution with 3 to 5 times distilled water 10 to 30% by weight of polyvinylidene fluoride cohexafluoropropylene was added to 90% by weight of dimethylacetamide through a step of uniformly mixing 0.05 to 0.2 times hydrochloric acid of the prepared solution at a molar concentration ratio to prepare an inorganic solution. After dissolving to 70% by weight to prepare an organic polymer solution, the organic polymer solution to 40% to 60% by weight, the tetraethoxysilane inorganic solution is mixed by 60% to 40% by weight for 12 hours Through the steps of preparing an organic and inorganic hybrid solution, the resultant hybrid solution is spun and applied to the surface of the support to form a hybrid hollow fiber membrane, thereby forming a hybrid hollow fiber membrane In ryusu through the step of completely removing the organic solvent remaining by immersion for 24 hours, it relates to a hollow fiber membrane produced by the method and a production method for producing a functional organic and inorganic hybrid polymer hollow fiber.

Look at the drawings in accordance with the present invention. 1 is a photograph of the surface of a hollow fiber membrane prepared according to Example 2 of the present invention through a scanning electron microscope, Figure 2 is a cross-sectional view of the hollow fiber membrane prepared according to Example 2 of the present invention The picture was taken through. 3 is a photograph of the surface of the hollow fiber membrane prepared according to Example 3 of the present invention through a scanning electron microscope, Figure 4 is a cross-sectional view of the hollow fiber membrane prepared according to Example 3 of the present invention The picture was taken through. 5 is a photograph taken with a scanning electron microscope of the surface of the hollow fiber membrane prepared according to Example 4 of the present invention, Figure 6 is a cross-sectional view of the hollow fiber membrane prepared according to Example 4 of the present invention The picture was taken through. 7 is a photograph of the surface of the hollow fiber membrane prepared according to Example 5 of the present invention using a scanning electron microscope, Figure 8 is a scanning electron microscope of the surface of the hollow fiber membrane prepared according to Example 6 of the present invention The picture was taken through. 9 is a photograph taken with a scanning electron microscope of the surface of the hollow fiber membrane prepared according to Example 7 of the present invention.

The hollow fiber membrane prepared according to the present invention has a film-forming solution on a tubular polypropylene (PP) support (outer diameter; 2.0 mm, inner diameter; 1.5 mm) woven as an asymmetric membrane having a skin layer having a finger structure and a lower layer having a sponge structure. The hollow fiber membranes were prepared by coating and phase change method. An important factor that determines the properties of the hollow fiber membranes in the phase transition process is highly dependent on the mixing ratio of additives such as solvents and coagulants.

Solvents used in the preparation of the film forming solution are dimethylacetamide (DMAc), dimethylformamide (DMF), methylpyrrolidone (NMP), triethylphosphate (TEP), dimethylsulfoxide (DMSO) and tetrahydrofuran (THF) One of the coagulants was selected, and a coagulant was used for water or a mixture of water and an organic solvent.

Polymers such as polyvinylidenedifluoride have to be added to the pore former because the hydrophobicity is so strong that it is not easy to exchange coagulants and solvents during the phase transition process. Commonly used additives are soluble in both solvents and non-solvents and easily form pores. Lithium chloride (LiCl), polyethylene glycol (PEG), polyethylene oxide (PEO), and polyvinylpyrrolidone (PVP) Was used.

The manufacturing method of the hollow fiber membrane for achieving this invention, and the structure of the hollow fiber membrane manufactured by the manufacturing method are demonstrated in detail.

a) Polyvinylidene fluoride cohexafluoropropylene hollow fiber membrane manufacturing method, 10% to 30% by weight of polyvinylidene fluoride cohexafluoropropylene dissolved in 90% to 70% by weight of dimethylacetamide organic polymer After the step of preparing a solution, the prepared organic polymer solution is sprayed with a spray nozzle and applied to the surface of the support to form a hollow fiber membrane, and the support on which the organic polymer solution is applied is immersed in distilled water for 24 hours. A polyvinylidene fluoride cohexafluoropropylene hollow fiber membrane was prepared by completely removing the organic solvent.

b) Polyvinylidene fluoride cohexafluoropropylene and tetraethoxysilane hybrid hollow fiber membrane production method, wherein the tetraethoxysilane at room temperature to 30% to 50% by volume, ethanol 70% to 50% by volume Dissolving to form a solution, and uniformly mixing 3 to 5 times distilled water of the composition solution and 0.05 to 0.2 times hydrochloric acid of the composition solution in a molar concentration ratio to prepare an inorganic solution, polyvinylidene fluorine Dissolving 10% to 30% by weight of lycocofluorofluoropropylene in 90% to 70% by weight of dimethylacetamide to prepare an organic polymer solution, the organic polymer solution is 40% to 60% by weight, After mixing the tetraethoxysilane inorganic solution at 60% by weight to 40% by weight for 12 hours to prepare an organic and inorganic hybrid film forming solution, the prepared hybrid film forming The liquid is sprayed with a spray nozzle to coat the surface of the support to form a hybrid polymer hollow fiber membrane, and the mixed polymer hollow fiber membrane is immersed in distilled water for 24 hours to completely remove the remaining organic solvent. A hollow fiber membrane was prepared.

c) Polyvinylidene difluoride hollow fiber membrane manufacturing method, polyvinylidene difluoride is 10% to 30% by weight, lithium chloride is 1.0% to 10% by weight, and dimethylacetamide Dissolving in 89 to 60% by weight to prepare a film forming solution, by spinning the film forming solution with a spray nozzle to apply a surface of the support to form a hollow fiber membrane, the formed hollow fiber membrane in distilled water for 24 hours The hollow fiber membrane was prepared by immersing to completely remove the remaining organic solvent.

Since the polyvinylidene difluoride has a high hydrophobicity, lithium chloride was used as an additive for pore formation. When the concentration of lithium chloride is 1.0 wt% or less, the phase transition rate is slow, and when the concentration exceeds 10 wt%, It is very important to properly control the concentration of lithium chloride because recrystallization of the polymer may occur. In addition, as the content of lithium chloride increases, the pore size and pore distribution (porosity) of the manufactured hollow fiber membranes increase.

d) surface modification of hollow fiber membranes

In order to examine the chemical durability of the hollow fiber membranes prepared by the hollow fiber membrane production method of a), b) and c), the hollow fiber membranes were used for 0.5 to 3 hours at a base solution of 0.01 M to 2.0 M sodium hydroxide solution at 40 ° C. It was immersed.

e) Module production of hollow fiber membranes

There are three types of hollow fiber membrane modules applied to water treatment, I-shaped, U-shaped, and vertical type, and U-shaped membrane can easily remove contaminants through aeration, etc. Because of this damage to the surface of the separation membrane, the hollow fiber membrane module of I type and vertical type was fabricated.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the protection scope of the present invention is not limited to the numerical values set forth in the Examples.

EXAMPLES

Example 1

A polypropylene (PP) support (outer diameter; 2.0 mm, inner diameter; 1.5) was prepared by dissolving polyvinylidene fluoride cohexafluoropropylene in 20% by weight and dimethylacetamide in 80% by weight to prepare a film forming solution. The membrane is coated with the surface of the support with a spray nozzle while rotating the membrane at a constant speed to form an organic polymer membrane.The organic polymer membrane is formed by distilled water as a coagulant and the organic solvent is completely removed by a phase-transfer method. Was prepared.

Example 2

Distilled water, hydrochloric acid, ethanol and tetraethoxysilane were mixed in a ratio of 4: 0.1: 0.7: 0.3 mol, respectively, to prepare an inorganic solution. 80 wt% of the organic polymer solution prepared in Example 1 was mixed and 20 wt% of the prepared inorganic solution was prepared to prepare a film forming solution, and then a polypropylene (PP) support (outer diameter; 2.0 mm, inner diameter; 1.5). Mm) was applied to prepare an organic and inorganic hybrid hollow fiber membrane. A relatively thick hollow fiber membrane was prepared by slowing down the spinning speed of the used sand film during film formation, and the thickness of the prepared hollow fiber membrane was 250 μm or more.

Example 3

The organic and inorganic hybrid hollow fiber membranes were prepared in the same manner as in Example 1 using the film forming solution prepared in Example 2. When forming the film, a relatively thin thickness of the hollow fiber membrane was prepared by increasing the spinning speed of the hollow fiber membrane, and the thickness of the prepared hollow fiber membrane was about 10 μm to 50 μm.

Example 4

15% by weight of polyvinylidene difluoride, 5% by weight of lithium chlorite, 80% by weight of dimethylacetamide were mixed and dissolved to prepare a film forming solution. The surface was applied to prepare a hollow fiber membrane. At this time, the thickness of the prepared hollow fiber membrane was about 100 to 200 ㎛.

Experimental Example 1

Photographs were taken by scanning electron microscopy (SEM) of the surface and cross section of the hollow fiber membranes prepared in Examples 2 to 4, and the photographs are shown in FIGS. 1 to 6.

Experimental Example 2

Tensile strength tests were performed to examine the mechanical strength of the hollow fiber membranes prepared in Examples 1, 2, and 4, and the measurement results are shown in Table 1. Table 1 shows the mechanical strength of the hollow fiber membranes prepared according to Examples 1 and 2 and 4.

Table 1. Mechanical Strength of Hollow Fiber Membranes Prepared by Examples 1, 2 and 4

Example 5

After the hollow fiber membrane prepared in Example 2 was immersed in 0.1 M sodium hydroxide solution at 40 ℃ for 1 hour, the surface of the hollow fiber membrane was taken with a scanning electron microscope (SEM), the photograph is shown in Figure 7 .

Example 6

After the hollow fiber membrane prepared in Example 3 was immersed in 0.1 M sodium hydroxide solution at 40 ° C. for 1 hour, the surface of the hollow fiber membrane was photographed by scanning electron microscope (SEM), and the photograph was shown in FIG. 8. .

Example 7

After the hollow fiber membrane prepared in Example 4 was immersed in 0.1M sodium hydroxide solution at 40 ° C. for 1 hour, the surface of the hollow fiber membrane was photographed with a scanning electron microscope (SEM), and the photograph is shown in FIG. 9. .

Example 8

A hollow fiber membrane having an outer diameter of 2 mm and an inner diameter of 1.5 mm prepared in Examples 2 to 4 was collected with 40 strands of 150 mm in length and fixed to both ends of a stainless steel tube by using epoxy to fix the surface area of the hollow fiber membrane of 0.038 m 2. Phosphor I type hollow fiber membrane module was prepared, and the filling density of the hollow fiber membrane was 40%.

Example 9

In order to examine the permeation characteristics of the hollow fiber membranes, the pure permeability and the solute permeation characteristics of the hollow fiber membrane module prepared in Example 8 were performed using a vacuum pump. Polyethylene oxide (PEO) 200,000 and 400,000 were used as a solute, and after performing the permeation experiment, the permeation characteristics are shown in Table 2. The concentration of PEO solution used was 1,000 ppm, the pressure used was 40 cmHg, and the result was measured after 30 minutes of operation at each pressure. Permeability and solute rejection were calculated by the following equations (1) and (2).

Equation 1

Equation 2

Table 2. Permeation Characteristics of Hollow Fiber Membranes Prepared by Example 8

The present invention provides a film forming solution by mixing polyvinylidene fluoride cohexafluoropropylene, an organic copolymer, and tetraethoxysilane, an inorganic material, by a phase-transfer method, to control pore size and distribution, and to be applicable to various water treatment processes. Functional hybrid hollow fiber membrane manufacturing method reinforced with a support having excellent mechanical strength, physical and chemical durability, and excellent permeation performance, and a hollow fiber membrane produced by the manufacturing method can be provided, the industrial applicability is high.

1 is a surface photograph of a hollow fiber membrane prepared according to Example 2 of the present invention (scanning electron microscope)

Figure 2: Hollow fiber membrane cross-sectional photograph prepared according to Example 2 of the present invention (scanning electron microscope)

Figure 3: Surface photograph (scanning electron microscope) of the hollow fiber membrane prepared according to Example 3 of the present invention

Figure 4: Hollow fiber membrane cross-sectional photograph prepared according to Example 3 of the present invention (scanning electron microscope)

Figure 5: Surface photograph (scanning electron microscope) of the hollow fiber membrane prepared according to Example 4 of the present invention

Figure 6: Hollow fiber membrane cross-sectional photograph prepared according to Example 4 of the present invention (scanning electron microscope)

7 is a surface photograph of a hollow fiber membrane prepared according to Example 5 of the present invention (scanning electron microscope)

Figure 8: Surface photograph (scanning electron microscope) of the hollow fiber membrane prepared according to Example 6 of the present invention

Figure 9: Surface photograph (scanning electron microscope) of the hollow fiber membrane prepared according to Example 7 of the present invention

Claims (12)

In the method for producing a hollow fiber membrane reinforced with a support, Preparing an organic polymer solution which greatly increases the effective area of the membrane and which is easily prepared by modifying the structure of the membrane; Preparing an inorganic solution having excellent chemical resistance and being applicable at a high temperature; Mixing the organic polymer solution and the inorganic solution and applying the mixture to a support to form a hollow fiber membrane; And Method for producing an organic and inorganic hybrid polymer hollow fiber membrane reinforced with a support consisting of removing the organic solvent by immersing the support on which the hollow fiber membrane is formed in distilled water. The method according to claim 1, The organic polymer solution is polyvinylidene difluoride, polymethyl methacrylate, polyacrylonitrile, polyvinylpyrrolidone, polyvinylidene fluoride cohexafluoropropylene copolymer, polyvinylidene fluoride coatrifluoro A method for producing an organic and inorganic hybrid hollow fiber membrane reinforced with a support, characterized in that it is prepared by selecting one of ethylene and polyethylene cotetrafluoroethylene or mixing two or more thereof. The method according to claim 1 or 2, The organic polymer solution is 10% to 30% by weight, and the inorganic solution is prepared by mixing 90% to 70% by weight ratio of organic and inorganic hybrid hollow fiber membrane reinforced with a support. The method according to claim 1, The inorganic solution may be prepared by selecting one of alkoxyl groups including tetraethoxysilane, tetramethoxysilane, tetrapropylorthosilicate and ethylpyridinetrimethoxysilane, or a support prepared by mixing two or more inorganic materials. Reinforced organic and inorganic hybrid hollow fiber membrane manufacturing method. The method according to claim 4, The inorganic solution is 30 vol% to 50 vol% of tetraethoxysilane at room temperature, 70 vol% to 50 vol% of ethanol is dissolved to form a solution, and 3 to 5 times distilled water and the composition of the composition Method for producing an organic and inorganic hybrid hollow fiber membrane reinforced with a support prepared by mixing hydrochloric acid of 0.05 to 0.2 times of the prepared solution in a molar concentration ratio. The method according to claim 2 or 4, The organic polymer solution to 40 to 60% by weight, the inorganic solution of the organic and inorganic hybrid hollow fiber membrane production method reinforced with a support prepared in a ratio of 60% to 40% by weight. The method according to claim 1, The organic solvent used in the film forming solution is selected from dimethyl acetamide and dimethyl formamide, methylpyrididone, triethyl phosphate, dimethyl sulfoxide and tetrahydrofuhan, and the organically reinforced support, Inorganic hybrid hollow fiber membrane manufacturing method. The method according to claim 1 or 2, A method for producing an organic and inorganic hybrid hollow fiber membrane reinforced with a support, characterized in that the surface of the hollow fiber membrane is modified with a base solution. The method according to claim 8, The surface modification is a method for producing an organic and inorganic hybrid hollow fiber membrane reinforced with a support, characterized in that the solution of sodium hydroxide and potassium hydroxide ammonium hydroxide of 0.01 to 2.0M at 40 ℃ and soaked for 0.5 to 3 hours to modify the treatment. Claim 1, claim 2, claim 4, claim 5, claim 7 and claim 8 of the organic and inorganic hybrid hollow fiber membrane reinforced with a support prepared by the organic and inorganic hybrid hollow fiber membrane manufacturing method reinforced with the support of any one of claims. An organic and inorganic hybrid hollow fiber membrane reinforced with a support prepared by the organic and inorganic hybrid hollow fiber membrane manufacturing method of claim 3 reinforced. The organic and inorganic hybrid hollow fiber membrane reinforced with the support manufactured by the organic and inorganic hybrid hollow fiber membrane manufacturing method of Claim 6 reinforced.

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