KR101848817B1 - Multi-bore hollow fiber membrane - Google Patents

Abstract

In the porous hollow fiber membrane according to an embodiment of the present invention, a first hollow is formed at the center of the cross section, and N (N is a natural number of 3 or more) second hollows are formed so as to be uniformly isotropic with respect to the center portion And N concave portions are formed on the outer circumferential surface of the transverse section to connect between the second hollow and the second hollow body integrally, wherein the porous hollow fiber membrane comprises 40 wt% of polyvinylidene fluoride resin, The resultant mixture was discharged at a temperature of 240 캜 using a twin-screw extruder with a composition of 15% by weight of silica, 30% by weight of dioctyl phthalate and 15% by weight of dibutyl phthalate, After passing through an air chamber of 80 mm and solidifying in a water bath at 60 ° C, it was stretched by 50% in a water bath at 60 ° C and stabilized in hot air at 120 ° C.

Description

Multi-bore hollow fiber membrane < RTI ID = 0.0 >

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous hollow fiber membrane, and more particularly, to a porous hollow fiber membrane having a plurality of openings formed in a cross section of a hollow fiber and having a petal shape on the outer circumference thereof.

In general, membrane technology utilizes selective permeability of polymer materials, etc., and commercialized technology applied to the desalination process in the US in the 1960s. Unlike the distillation process, the membrane separation process using such a separation membrane is advantageous in that the space occupied by the apparatus is small because energy can be saved and the process is relatively simple since there is no phase change. Therefore, the membrane has been extensively applied to reverse osmosis (RO) separation processes, ultrafiltration (UF), microfiltration (MF), and nanofiltration (NF) separation processes.

In general, the separator may have a variety of shapes such as spiral wound, tubular, hollow fiber, and plat and frame. Of these, the hollow core has an inner median diameter of 0.2 to 2 mm Since it is a hollow tube type, the hollow fiber has an area ratio per unit volume and a high productivity as compared with a spiral, tubular and plate frame type.

In particular, in recent years, a hollow fiber membrane having a specific structure has been developed as compared with a conventional commercial hollow fiber membrane. Inge, Germany, has seven independent capillaries (hollow fibers) on a single fiber having a circular outer circumferential surface, Porous membrane (Multibore < RTI ID = 0.0 > membrane was commercialized. This hollow fiber membrane is applied to the ultrafiltration process for water treatment, so that the separation performance is superior to that of a conventional single-bore hollow fiber membrane in which only one capillary (hollow) is formed on a conventional single fiber, and mechanical properties and chemical stability And fouling prevention effect. However, there is still room for improvement in maximizing permeation performance, filtration efficiency and membrane fouling prevention performance (Patent Document 1)

Accordingly, the present inventors have conducted extensive research on a water treatment hollow fiber membrane having a new structure, and as a result, have found that a channel having a plurality of holes (multi-bore hollow) is formed in a short fiber constituting a hollow fiber, bore, and hollow) is designed to have a petal shape in which the concave portion and the convex portion are not circular but the pattern is repeated, the filling density and the specific surface area of the outer peripheral surface of the staple fiber are increased compared to the circular shape, And the permeation performance can be further improved, and the film fouling prevention performance can be greatly improved. Thus, the present invention has been accomplished.

International Patent Publication No. WO 2006/012920

It is an object of the present invention to provide a hollow fiber which has a plurality of hollows (holes) formed therein, which have improved packing density and specific surface area, and which not only improve filtration efficiency and permeability, The present invention is to provide a porous hollow fiber membrane in which a concave portion and a convex portion are repeatedly formed in the shape of petals on the outer peripheral surface of the hollow short fiber.

In the porous hollow fiber membrane according to the embodiment of the present invention, a first hollow is formed at the central portion of the cross section, and N (N is a natural number of 3 or more) second hollows are formed so as to be uniformly isotropic with reference to the center portion And N concave portions for integrally connecting the second hollow and the second hollow are formed on the outer circumferential surface of the transverse section, wherein the porous hollow fiber membrane comprises a polyvinylidene fluoride resin 40 , 15 wt% of silica, 30 wt% of dioctyl phthalate and 15 wt% of dibutyl phthalate using a twin-screw extruder at 240 캜 using a porous nozzle, and using dioctyl phthalate at 30 캜 And then passed through an air chamber of 80 mm and then solidified in a water bath at 60 DEG C and then stretched by 50% in a water bath at 60 DEG C and stabilized in hot air at 120 DEG C Can.
In the porous hollow fiber membrane according to the embodiment of the present invention, the material of the porous hollow fiber membrane is selected from the group consisting of polyethylene (PE) resin, polypropylene (PP) resin, ethylene chlorotrifluoroethylene resin (ECTFE) Polyvinylidene fluoride (PVDF) resin, polyacrylonitrile (PAN) resin, polyimide resin, polyamideimide resin and polyvinylidene chloride resin. Polyetherimide, and polyetherimide.
Also, in the porous hollow fiber membrane according to the embodiment of the present invention, the porous hollow fiber membrane may be manufactured by a conventional non-solvent-derived phase transition method (NIPS) or a thermally induced phase transfer method (TIPS).
Also, in the porous hollow fiber membrane according to the embodiment of the present invention, the porous hollow fiber membrane may be applied to a microfiltration membrane, an ultrafiltration membrane, a degassing membrane, and a pervaporation membrane.

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The features and advantages of the present invention will become more apparent from the following detailed description based on the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed in a conventional, dictionary sense, and should not be construed as defining the concept of a term appropriately in order to describe the inventor in his or her best way. It should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

The porous hollow fiber membrane according to the embodiment of the present invention has improved mechanical strength and packing density and specific surface area of the membrane compared with conventional hollow or porous hollow fiber membranes, thereby improving filtration efficiency and permeability, It can be applied to a microfiltration and ultrafiltration separation process for water treatment.

Further, there is an effect of providing a porous hollow fiber membrane in which a concave portion and a convex portion are formed on the outer peripheral surface of the hollow fiber glass with repeated petals.

In addition, since the distance between the second hollow and the convex portion is constant, there is an effect of providing a multi-construction membrane module having uniform permeability and uniform reliability of the product compared to the conventional hollow fiber membrane.

Further, since the distance between the second hollow and the convex portion is constant, the bending strength and the mechanical strength are improved as compared with the conventional circular shape.

1 is a perspective view of a porous hollow fiber membrane according to an embodiment of the present invention;
FIG. 2 is a cross-sectional view illustrating a first virtual circle diameter and a second virtual circle diameter of a porous hollow fiber membrane according to an embodiment of the present invention. FIG.
Fig. 3 is an exemplary view showing the form of Fig. 2; Fig.
4 is a cross-sectional exemplary view in which a first virtual circle diameter of a porous hollow fiber membrane according to an embodiment of the present invention is larger than a second virtual circle diameter.
FIG. 5 is an exemplary view showing the form of FIG. 4; FIG.
6 is a cross-sectional exemplary view in which a first virtual circle diameter of a porous hollow fiber membrane according to an embodiment of the present invention is smaller than a second virtual circle diameter.
FIG. 7 is an exemplary view showing the form of FIG. 6; FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The objects, particular advantages and novel features of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. It should be noted that, in the present specification, the reference numerals are added to the constituent elements of the drawings, and the same constituent elements are assigned the same number as much as possible even if they are displayed on different drawings. Also, the terms first, second, etc. may be used to describe various components, but the components should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a perspective view of a porous hollow fiber membrane according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a porous hollow fiber membrane according to an embodiment of the present invention. FIG. 4 is a cross-sectional view illustrating a first virtual circle diameter of the porous hollow fiber membrane according to an embodiment of the present invention, which is larger than the second virtual circle diameter; FIG. 6 is a cross-sectional view and a cross-sectional view in which a first imaginary circle diameter of the porous hollow fiber membrane according to an embodiment of the present invention is smaller than a second imaginary circle diameter, and Fig. 5 is an illustration showing an embodiment of Fig. 7 is an exemplary diagram showing a form for FIG.

1 to 3, a porous hollow fiber membrane according to an embodiment of the present invention includes a first hollow 100 formed at the center of a transverse section, an N (N is a natural number of 3 or more) second hollows 200 are formed on the outer surface of the transverse section, and N concave portions for integrally connecting the second hollow 200 and the second hollow 200 are formed do.

Referring to FIG. 1, the porous hollow fiber membrane 10 is formed in the form of a column having a first hollow 100 at a central portion thereof. At this time, the first hollow 100 serves as a passage through which the foreign substance or the purified substance moves. The second hollow (200) is formed uniformly in the back-light position with respect to the center of the first hollow (100). That is, it is appropriate that the second hollow 200 has N (N is a natural number of 3 or more) holes of the first hollow 100.

2 and 3, the porous hollow fiber membrane 10 includes a first imaginary circle 310 formed larger than the first hollow radius a1 on the basis of the center of the first hollow 100, A second imaginary circle 330 formed to be larger than the second hollow radius b1 on the basis of the concentric center of the first hollow space 200 and a second imaginary circle 330 formed to contact the second imaginary circle 330 inward from the concentric center of the first hollow 100 And a third virtual circle (350).

Referring to FIG. 2, the first imaginary circle 310 is larger than the first hollow radius a1, and is formed around the concentric circle of the first hollow 100. FIG. The first virtual circle 310 is formed so as to circumscribe the second virtual circle 330. The first imaginary circle 310 is disposed at a position where the second hollow 200 is uniformly radiated.

The second imaginary circle 330 is larger than the second hollow radius b1 and is formed around a concentric circle of the second hollow 200. The second virtual circle 330 is formed to circumscribe the first virtual circle 310. The second imaginary circle 330 is surrounded by N (N is a natural number of 3 or more) around the first imaginary circle 310. That is, the second hollow 200 is formed in the first hollow 100 so as to be equipotential, and the second hollow 200 is formed of N (N is a natural number of 3 or more).

The third imaginary circle 350 is formed to contact the second imaginary circle 330 at the center of the first hollow 100 inward. That is, the third imaginary circle 350 is formed at the outer peripheral surface size of the porous hollow fiber membrane 10 at the center of the first hollow 100.

Unevenness is formed on the outer circumferential surface of the porous hollow fiber membrane 10. The curvature of the irregularities 110 is formed corresponding to the number of the second hollows 200 arranged. That is, the irregularities 110 can be divided into a concave portion 111 and a convex portion 113. It is appropriate that the irregularities 110 are formed in a petal shape with respect to the cross section of the porous hollow fiber membrane 10. The porous hollow fiber membrane 10 has improved bending strength and mechanical strength compared with the conventional circular shape. That is, the porous hollow fiber membrane 10 has the function of holding the air injected vertically when installed in the filtration apparatus. A large amount of air pressure is formed on the surface of the porous hollow fiber 10 to improve the filtration efficiency.

The convex portion 110 is formed with a convex portion 113 at a portion formed by extending the second hollow 200 in the outer circumferential direction. The concavity and convexity 110 includes a concave portion 111 at a portion connecting the second hollow 200 and the second hollow 200 in the outer circumferential direction.

The convex portion 113 of the concave and convex 110 is formed so as to be in contact with the inside of the third imaginary circle 350 and the concave portion 111 of the concave and convex 110 is formed in contact with the second hollow 200 and the second hollow 200, . That is, the concave portion 111 is closely spaced from the space in which the second hollow 200 and the second hollow 200 are formed.

The concavity and convexity 110 is formed on the outer peripheral surface of the porous hollow fiber membrane 10, thereby improving the specific surface area and the filtration efficiency. In addition, the concavity and convexity 110 forms the concave portion 111 on the outer circumferential surface of the porous hollow fiber membrane 10, so that the concavity and convexity 110 can reduce the raw materials used in the production and improve the economical efficiency. The irregularities 110 also ensure uniform permeability and uniform reliability of the product compared to the conventional hollow fiber membranes by making the distance between the second hollow 200 and the convex portion 113 constant.

For example, when three second hollows 200 are formed as shown in FIG. 3A, the concave portion 111 is formed so as to approach the first hollow 100. That is, It can be seen that the concave portion 111 is in contact with the first imaginary circle 310. This does not mean that when the second hollows 200 are formed in three, the concave portion 111 is formed in the first imaginary circle 310 to be in contact with the first imaginary circle 310. That is, it means that the concave portion 111 is formed in the vicinity of the first imaginary circle 310.

3B to 3H, the porous hollow fiber membrane 10 is formed so that the concave portion 111 is away from the first hollow 100 when the second hollow 200 is increased by one. That is, when four or more second hollows 200 are formed, it can be seen that the concave portion 111 moves away from the first imaginary circle 310. That is, the concave portion 111 is formed so that the second hollow 200 gradually approaches the third virtual circle 350 while gradually moving away from the first virtual circle 310 when the second hollow 200 is increased. That is, the concave portion 111 is formed in the vicinity of the first virtual circle 310 as shown in Fig. 3A, and the concave portion 111 is formed in the vicinity of the third virtual circle 350 as shown in Fig. 3H can confirm. do.

The porous hollow fiber membrane 10 is formed such that the radius a2 of the first imaginary circle 310 and the radius b2 of the second imaginary circle are the same.

Meanwhile, the material of the porous hollow fiber membrane 10 may be a hydrophobic polymer including a vinyl polymer and an olefin polymer. Examples of the hydrophobic polymer include polyethylene resin, polypropylene resin, ethylene chlorotrifluoroethylene resin (ECTFE), polyvinyl chloride (PVC) resin, polysulfone resin, polyether sulfone resin, sulfonated polysulfone resin , Polyvinylidene fluoride (PVDF) resin, polyacrylonitrile (PAN) resin, polyimide resin, polyamideimide resin, and polyetherimide can be used. In particular, a fluorine-containing hydrophobic polymer such as a polyvinylidene fluoride (PVDF) homopolymer or a copolymer thereof is more preferably used in consideration of chemical stability.

In addition, the porous hollow fiber membrane 10 according to the present invention is obtained by dissolving the hydrophobic polymer described above in a solvent or, if necessary, in a solvent containing a non-solvent or an additive to obtain a spinning solution, (NIPS) or thermally induced phase separation (TIPS), which forms a hollow fiber which is completely phase-transformed by an external coagulant after discharging, .

Second Embodiment

4, the porous hollow fiber membrane 10 according to the second embodiment of the present invention is the same as that of the first embodiment except that the radius a2 of the first imaginary circle 310 is A case where the radius is larger than the radius b2 of two virtual circles 330 will be described in detail.

Unevenness is formed on the outer circumferential surface of the porous hollow fiber membrane 10. The curvature of the irregularities 110 is formed corresponding to the number of the second hollows 200 arranged. That is, the irregularities 110 can be divided into a concave portion 111 and a convex portion 113 (see FIG. 4).

The convex portion 110 is formed with a convex portion 113 at a portion formed by extending the second hollow 200 in the outer circumferential direction. The concavity and convexity 110 includes a concave portion 111 at a portion connecting the second hollow 200 and the second hollow 200 in the outer circumferential direction.

The convex portion 113 of the concave and convex 110 is formed so as to be in contact with the inside of the third imaginary circle 350 and the concave portion 111 of the concave and convex 110 is formed in contact with the second hollow 200 and the second hollow 200, . That is, the concave portion 111 is closely spaced from the space in which the second hollow 200 and the second hollow 200 are formed.

For example, when six second hollows 200 are formed as shown in FIG. 5A, the concave portion 111 has a depth of " v " shape in the first hollow 100 direction.

Referring to FIGS. 5A to 5D, the second hollow 200 of the porous hollow fiber membrane 10 is increased by one. When the concave portion 111 is formed between the second hollow 200 and the second hollow 200, the concave portion 111 is formed to be away from the first hollow 100. That is, when seven or more second hollows 200 are formed, it can be seen that the concave portion 111 moves away from the first imaginary circle 310. That is, the concave portion 111 is formed so as to approach the third imaginary circle 350 gradually away from the first imaginary circle 310.

Third Embodiment

6, the porous hollow fiber membrane 10 according to the third embodiment of the present invention is the same as that of the first embodiment except that the radius a2 of the first imaginary circle 310 is A case where the radius is smaller than the radius b2 of two virtual circles 330 will be described in detail.

The filtration efficiency can be increased while reducing the diameter of the porous hollow fiber membrane 10. The porous hollow fiber membrane 10 is formed such that the radius a2 of the first virtual circle 310 is smaller and the radius b2 of the second virtual circle 330 of the porous hollow fiber membrane 10 is increased. That is, it is possible to increase the filtration efficiency and packing density by increasing the radius b1 of the second hollow 200 of the outer surface of the porous hollow fiber membrane 10 (see FIG. 6 or 7).

 Unevenness is formed on the outer circumferential surface of the porous hollow fiber membrane 10. The curvature of the irregularities 110 is formed corresponding to the number of the second hollows 200 arranged. That is, the irregularities 110 can be divided into a concave portion 111 and a convex portion 113 (see FIG. 6).

The convex portion 110 is formed with a convex portion 113 at a portion formed by extending the second hollow 200 in the outer circumferential direction. The concavity and convexity 110 includes a concave portion 111 at a portion connecting the second hollow 200 and the second hollow 200 in the outer circumferential direction.

The convex portion 113 of the concave and convex 110 is formed so as to be in contact with the inside of the third imaginary circle 350 and the concave portion 111 of the concave and convex 110 is formed in contact with the second hollow 200 and the second hollow 200, . That is, the concave portion 111 is closely spaced from the space in which the second hollow 200 and the second hollow 200 are formed.

For example, when three second hollows 200 are formed as shown in FIG. 6A, the concave portions 111 are formed to have a depth of "v" shape in the first hollow 100 direction.

Referring to FIGS. 7A to 7C, the second hollow 200 of the porous hollow fiber membrane 10 is increased by one. At this time, if one concave portion 111 is formed between the second hollow 200 and the second hollow 200, the concave portion 111 is formed to be away from the first hollow 100. That is, when four or more second hollows 200 are formed, it can be seen that the concave portion 111 moves away from the first imaginary circle 310. That is, the concave portion 111 is formed so as to approach the third imaginary circle 350 gradually away from the first imaginary circle 310.

Hereinafter, an experimental example of evaluating the water permeability and the mechanical properties of a hollow fiber membrane having a petal shape in which concave portions and convex portions are repeatedly formed on the outer circumferential surface of the hollow fiber membrane according to an embodiment of the present invention is described. .

[Experimental Example]

(Weight average molecular weight: 300,000 to 320,000), 15% by weight of silica, 30% by weight of dioctyl phthalate, and 40% by weight of dibutyl phthalate using a multi-bore nozzle having an outer diameter of the nozzle shape of petals And 15% by weight of phthalate was discharged at 240 캜 using a twin-screw extruder. Dioctyl phthalate was used as a hollow forming agent at 30 ° C. After passing through an air chamber of 80 mm, it was solidified in a water bath of 60 ° C., then drawn at 50 ° C. in a water bath at 60 ° C., stabilized by hot air at 120 ° C., The winding speed was adjusted to 15 m / min to prepare a porous hollow fiber membrane having an outer peripheral surface of petal shape as shown in Fig. 1 (outer diameter: 4.2 mu m, inner diameter: 0.8 mu m). The porous hollow fiber membrane having the petroleum-shaped outer surface was immersed in methylene chloride for 30 minutes, immersed in an aqueous solution of 8% by weight of sodium hydroxide for 15 minutes, immersed in ethanol for 10 minutes, immersed in an aqueous 3 wt% solution of glycerin for 24 hours and dried The water permeability and mechanical properties were evaluated through the treatment, and the results are shown in Table 1.

[Comparative Example]

Porous hollow fiber membranes having circular outer circumferential surfaces were manufactured in the same manner as in the above Experimental Example except that a nozzle having a circular outer diameter was used, and water permeability and mechanical properties were evaluated through post- Respectively.

Sample Water permeation flux (L / m 2. Hr, 0.1 mpa) Maximum breaking load (N) Elongation at break (%) Experimental Example 3,600 46.9 120 Comparative Example 2,100 36.2 80

As shown in Table 1, according to one embodiment of the present invention, the perforated hollow fiber membrane having an outer circumferential surface of petal shape manufactured from the above Experimental Example has a water permeability higher than that of a porous hollow fiber membrane having a circular outer circumferential surface, It can be confirmed that the outer shape of the nozzle is a petal shape because the heat transfer is uniform in the process of forming the hollow fiber membrane and the surface area is large.

Also, in terms of mechanical properties such as maximum breaking load and elongation at break, according to one embodiment of the present invention, the porous hollow fiber membrane having the petroleum-shaped outer peripheral surface manufactured from the above Experimental Example is a porous multi- The porous hollow fiber membrane having an outer circumferential surface of petal shape is formed with a bone during the hollow fiber membrane formation process, so that it is well-oriented at the time of stretching to increase the strength, and the pores are uniformly formed, And the elongation is improved.

Therefore, according to the porous hollow fiber membrane of the present invention, the filling density and the specific surface area are increased as compared with the conventional single-hole or multi-porous hollow fiber membrane, thereby improving filtration efficiency and permeation performance, It can be applied to an ultrafiltration membrane, a degassing membrane, and a pervaporation membrane separation process.

Although the technical idea of the present invention has been specifically described according to the above preferred embodiments, it is to be noted that the above-described embodiments are intended to be illustrative and not restrictive. 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 invention.

10: Porous hollow fiber membrane 100: First hollow
110: concave 111: concave
113: convex portion 200: second hollow
310: first virtual circle 330: second virtual circle
350: Third Virtual Circle

Claims (8)

Wherein a first hollow is formed at a central portion of the cross section and is arranged so as to be uniformly isotropic with respect to the central portion, and N second hollows (N is a natural number of 3 or more) are formed, And N concave portions for connecting the second hollows integrally are formed,
The porous multi-
40% by weight of polyvinylidene fluoride resin, 15% by weight of silica, 30% by weight of dioctyl phthalate and 15% by weight of dibutyl phthalate by using a biaxial extruder at 240 DEG C using a porous nozzle, Octyl phthalate was used at 30 DEG C to form the first hollow and the second hollow. After passing through an air chamber of 80 mm, it was coagulated in a water bath at 60 DEG C and then drawn at 50 DEG C in a water bath at 60 DEG C, Wherein the porous hollow fiber membrane is stabilized in the porous hollow fiber membrane. delete delete delete delete The method according to claim 1,
Wherein the porous hollow fiber membrane is made of a material selected from the group consisting of polyethylene resin, polypropylene resin, ethylene chlorotrifluoroethylene resin (ECTFE), polyvinyl chloride (PVC) resin, polysulfone resin, (Polyvinylidene fluoride) resin, a polyacrylonitrile (PAN) resin, a polyimide resin, a polyamideimide resin and a polyetherimide. Hollow hollow fiber membrane. The method according to claim 1,
Wherein the porous hollow fiber membrane is manufactured by a conventional non-solvent-derived phase transition method (NIPS) or a thermally induced phase transfer method (TIPS). The method according to claim 1,
Wherein the porous hollow fiber membrane is applied to a microfiltration membrane, an ultrafiltration membrane, a desulfurization membrane, and a pervaporation membrane.

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