KR102022264B1 - Manufacturing Method of Hollow Fiber Membrane using Organic acids - Google Patents

Abstract

The present invention relates to a manufacturing method of a hollow fiber membrane using an organic acid, comprising: a step (A) of putting a polysulfone (PSF) polymer resin and carboxy acid-based organic acid and additives into a solvent and mixing the same to manufacture a polymer solution; a step (B) of agitating the polymer solution at 20-25°C; a step (C) of using a spinning nozzle to spin the polymer solution passed through the step of (B) to coagulation bath having a solidification solution of 45-60°C to solidify the same; and a step (D) of immersing the solidifying product passed through the step of (C) in a precipitation tank having water of 15-25°C filled therein for 20-24 hours to remove the solvent and non-solvent. In the step (C), a condition of 60% or more humidity is required to form pores of a hollow fiber membrane manufactured uniformly and improve a water permeability. The present invention can to manufacture a polysulfone hollow fiber membrane having porosity which has a greatly excellent permeation rate compared with pore sizes by using organic acids and polysulfones, can manufacture a polysulfone hollow fiber membrane which has excellent performances in terms of porosity and permeation rate rather than hollow fiber membranes based on existing polysulfone polymer resins, and can manufacture a hollow fiber membrane having a performance very fitted for water treatment.

Description

 Manufacturing Method of Hollow Fiber Membrane Using Organic Acids

The present invention relates to a hollow fiber membrane manufacturing method using an organic acid, and more particularly, a polymer composition comprising polysulfone (PSF) polymer and a carboxylic acid-based organic acid for forming pores on the surface of the membrane as an additive and spinning the same The present invention relates to a hollow fiber membrane manufacturing method using an organic acid, which is capable of producing a hollow fiber membrane having excellent porosity by exposing for a few minutes at an appropriate temperature and high humidity conditions and then immersing in water at room temperature.

In general, during the preparation of the separator, a polymer solution is prepared by adding other additives in addition to the basic polymer and dissolving it in a solvent.

At this time, the performance of the shape, pore size, permeability, etc. of the membrane is greatly changed depending on the type and amount of the additive added to the polymer solution, so the additive is one of the important factors in the membrane production.

As the application and field of use of the separators expands, there is a demand for separators with high economic strength such as high mechanical strength, chemical resistance, and fouling resistance, and in order to satisfy the properties of such membranes, selection of polymers used in membrane manufacturing is very important. Do.

For example, polysulfone is widely known as a polymer for preparing a membrane having excellent mechanical strength, chemical resistance, and thermal stability, and many attempts have been made to use additives having high affinity with water vapor in the process of preparing a membrane using a vapor induction phase separation method. Most of them use polyethylene glycol, polyvinylpyrrolidone, or salts or toluenesulfonic acid as additives.

However, there is a technical limitation in producing a membrane by a highly porous hollow fiber membrane and there is a difficulty in having an excellent permeate flow rate, and there is a demand for a technique having a better permeate flow rate and improved separation performance.

Furthermore, research and development have been actively conducted to maximize performances such as pore size and permeate flow rate when preparing a hollow fiber membrane using various polymers and adding other additives to prepare a hollow fiber membrane and a separator using the same.

(Patent Document 1) Republic of Korea Patent Registration No. 10-1409965

(Patent Document 2) Republic of Korea Patent Publication No. 10-2018-0016142

The present invention has been made in view of the above-described improvement and the like, a polymer composition comprising a polysulfone (PSF) polymer and a carboxylic acid-based organic acid for forming pores on the membrane surface as an additive and after spinning It is an object of the present invention to provide a method for producing a hollow fiber membrane using an organic acid, which is capable of producing a hollow fiber membrane having excellent porosity by exposing for a few minutes at an appropriate temperature and a high humidity condition and immersing in water at room temperature.

The present invention is to provide a hollow fiber membrane manufacturing method using an organic acid to exhibit a function that is very suitable for water treatment by manufacturing so that the porosity and permeate flow rate is superior to the conventional hollow fiber membrane based on polysulfone polymer. .

The hollow fiber membrane manufacturing method using the organic acid according to the present invention for achieving the above object, in the hollow fiber membrane manufacturing method for producing a hollow fiber membrane after preparing a polymer solution using a polysulfone as a polymer resin, (A) polysulfone (PSF) preparing a polymer solution by mixing a polymer resin with a carboxylic acid-based organic acid and an additive in a solvent; (B) stirring the polymer solution at room temperature of 20 ° C. to 25 ° C .: (C) using a spinning nozzle in a coagulation bath having a coagulation solution of 45 ° C. to 60 ° C. with respect to the polymer solution passed through step (B). Solidifying by spinning; (D) removing the solvent and the non-solvent by immersing the solid product passed through the step (C) in a precipitation tank filled with water of 15 ° C to 25 ° C for 20 to 24 hours; in the step (C), The pores of the hollow fiber membrane to be produced are characterized in that it has a condition of humidity of 60% or more to uniformly form and increase the water permeability.

Here, in the step (A), 15 to 35 parts by weight of polysulfone (PSF) polymer resin, 3 to 15 parts by weight of carboxylic acid-based organic acid, 10 to 20 parts by weight of additives are mixed based on 100 to 120 parts by weight of solvent. It is characterized by preparing a solution.

Wherein the solvent is dimethylacetamide (DMAc); The carboxylic acid-based organic acid is an organic acid having one or more carboxylic acids; The additive is characterized by using a combination of polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP).

Here, the carboxylic acid-based organic acid is characterized in that one selected from lactic acid, succinic acid, citric acid, malonic acid, maleic acid, benzoic acid.

Here, polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) used as the additive is characterized in that the polyethylene glycol: polyvinylpyrrolidone = 0.5 to 1: 1 to 1.5 by weight.

According to the present invention, it is possible to achieve a useful effect of producing a polysulfone hollow fiber membrane having an extremely excellent porosity relative to the pore size using the organic acid.

The present invention can produce a polysulfone hollow fiber membrane having a superior performance in porosity and permeate flow rate than the hollow fiber membrane based on a conventional polysulfone polymer resin, and a useful effect of producing a hollow fiber membrane having a very suitable performance for water treatment. Can be achieved.

1 is a manufacturing process chart showing a hollow fiber membrane manufacturing method using an organic acid according to an embodiment of the present invention.
Figure 2 is a SEM image of the surface of the hollow fiber membrane prepared in Example 1 in the present invention.
Figure 3 is a SEM image of the surface of the hollow fiber membrane prepared in Example 2 in the present invention.
Figure 4 is a SEM image of the surface of the hollow fiber membrane prepared in Example 3 in the present invention.
5 is a SEM image of the surface of the hollow fiber membrane prepared according to Example 4 in the present invention.
Figure 6 is a SEM image of the surface of the hollow fiber membrane prepared in Example 5 in the present invention.
Figure 7 is a SEM image of the surface of the hollow fiber membrane prepared in Example 6 in the present invention.
8 is a SEM image of the surface of the hollow fiber membrane prepared according to Comparative Example 1 in the present invention.
9 is a SEM image of the surface of the hollow fiber membrane prepared in Comparative Example 2 in the present invention.
10 is a SEM image of the surface of the hollow fiber membrane prepared in Comparative Example 3 in the present invention.
11 is a SEM image of the surface of the hollow fiber membrane prepared in Comparative Example 4 in the present invention.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings, and the detailed description will provide a better understanding of the purpose, configuration, and features thereof.

Hollow fiber membrane manufacturing method using an organic acid according to an embodiment of the present invention, as shown in Figure 1, the polymer solution manufacturing step (S10), polymer solution stirring step (S20), hollow fiber membrane manufacturing step (S30), immersion step (S40) It consists of a configuration including.

In the preparing of the polymer solution (S10), a polysulfone (PSF) polymer resin, a carboxylic acid-based organic acid, and an additive are mixed in a solvent to prepare a polymer solution.

At this time, the polymer solution manufacturing step (S10) is based on 100 to 120 parts by weight of solvent polysulfone (PSF) polymer resin 15 to 35 parts by weight, carboxylic acid-based organic acid 3 to 15 parts by weight, additives 10 to 20 parts by weight of Prepare a polymer solution.

Here, when the polysulfone (PSF) polymer resin is less than 15 parts by weight, the viscosity of the polymer solution is low, not only the shape of the hollow fiber membrane is not uniformly formed, but the strength is weakened, 30 parts by weight If exceeded, the strength can be improved, but the water permeability decreases rapidly.

Herein, when the carboxylic acid-based organic acid is used, the pore size and permeation flow rate of the hollow fiber membrane to be manufactured are extremely low when the carboxylic acid-based organic acid is used, and when the amount exceeds 15 parts by weight, the permeation flow rate is lowered compared to the pore size. Occurs.

As the solvent, dimethylacetamide (DMAc) is preferably used to dissolve polysulfone (PSF), carboxylic acid-based organic acid and additives so as to easily prepare a polymer solution.

The carboxylic acid-based organic acid is preferably an organic acid having one or more carboxylic acids to maximize the permeation flow rate compared to the pore size to improve performance, more preferably selected from lactic acid, succinic acid, citric acid, malonic acid, maleic acid, benzoic acid Either one can be used.

As the additive, it is preferable to use polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) together to use as a plasticizer for improving performance.

In this case, the polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) may be added in a weight ratio of polyethylene glycol: polyvinylpyrrolidone = 0.5 to 1: 1 to 1.5.

The polymer solution stirring step (S20) is a step of stirring the polymer solution prepared through the step S10 at a room temperature of 20 ℃ to 25 ℃, it is a step to allow the compositions constituting the polymer solution to be better mixed.

The hollow fiber membrane manufacturing step (S30) is a step of solidifying treatment by spinning with a spinning nozzle in a coagulation bath having a coagulating solution of 45 ℃ to 60 ℃ for the polymer solution undergoing the polymer solution stirring step (S20), through It is a step of preparing a hollow fiber membrane having pores for the porous structure.

In this case, the hollow fiber membrane manufacturing step (S30) is preferably carried out in a state having a humidity of 60% or more in order to uniformly form the pores of the hollow fiber membrane to be manufactured and to increase the water permeability.

Here, in providing the humidity condition, if the humidity is less than 60%, the pores of the surface are irregularly formed, as well as the water permeability is greatly reduced.

Here, the humidity conditions are more preferably carried out in a condition having a humidity of 90% or more so as to greatly improve the uniformity and water permeability of the pores of the hollow fiber membrane to be produced.

The immersion step (S40) is a solvent and by immersing the hollow fiber membrane having a solid for the hollow fiber membrane manufacturing step (S30), that is, the porous fiber having pores for the porous structure for 20 to 24 hours in a water-filled sedimentation tank of 15 ℃ to 25 ℃ This step is to remove nonsolvent.

Through the above-described steps, it is possible to produce a hollow fiber membrane having excellent quality and suitable for water treatment, and in particular, to produce a hollow fiber membrane having a very high porosity relative to the pore size and having a very high porosity, and based on a conventional polysulfone polymer resin. The hollow fiber membrane having a porous structure and a permeate flow rate superior to that of the hollow fiber membrane can be produced.

Hereinafter, specific examples and experimental examples of the hollow fiber membrane using the organic acid prepared according to the present invention will be described.

(Example 1)

20 parts by weight of polysulfone (PSF), 112 parts by weight of dimethylacetamide (DMAc), 4.5 parts by weight of citric acid, 5 parts by weight of polyethylene glycol and 10 parts by weight of polyvinylpyrrolidone were mixed to prepare a polymer solution. The mixture was stirred again at room temperature (20 ° C.), and the polymer solution was spun into a coagulation bath having a coagulation solution of 50 ° C., but at 90% humidity to prepare a solidification treatment and a hollow fiber membrane, and the hollow fiber membrane was filled with water at 20 ° C. The polysulfone hollow fiber membrane was completed by immersion in a precipitation tank for 24 hours.

(Example 2)

A polymer solution was prepared by mixing 22 parts by weight of polysulfone (PSF), 110 parts by weight of dimethylacetamide (DMAc), 4.5 parts by weight of citric acid, 5 parts by weight of polyethylene glycol, and 10 parts by weight of polyvinylpyrrolidone. After stirring again at room temperature (20 ° C.), polysulfone hollow fiber membranes were completed in the same manner as in Example 1.

(Example 3)

A polymer solution was prepared by mixing 23 parts by weight of polysulfone (PSF), 108 parts by weight of dimethylacetamide (DMAc), 4.5 parts by weight of citric acid, 5 parts by weight of polyethylene glycol, and 10 parts by weight of polyvinylpyrrolidone. After stirring again at room temperature (20 ° C.), polysulfone hollow fiber membranes were completed in the same manner as in Example 1.

(Example 4)

A polymer solution was prepared by mixing 23 parts by weight of polysulfone (PSF), 112 parts by weight of dimethylacetamide (DMAc), 3 parts by weight of citric acid, 5 parts by weight of polyethylene glycol, and 10 parts by weight of polyvinylpyrrolidone. After stirring again at room temperature (20 ° C.), polysulfone hollow fiber membranes were completed in the same manner as in Example 1.

(Example 5)

A polymer solution was prepared by mixing 23 parts by weight of polysulfone (PSF), 106 parts by weight of dimethylacetamide (DMAc), 8 parts by weight of citric acid, 5 parts by weight of polyethylene glycol, and 10 parts by weight of polyvinylpyrrolidone. After stirring again at room temperature (20 ° C.), polysulfone hollow fiber membranes were completed in the same manner as in Example 1.

(Example 6)

A polymer solution was prepared by mixing 23 parts by weight of polysulfone (PSF), 103 parts by weight of dimethylacetamide (DMAc), 11 parts by weight of citric acid, 5 parts by weight of polyethylene glycol, and 10 parts by weight of polyvinylpyrrolidone. After stirring again at room temperature (20 ° C.), polysulfone hollow fiber membranes were completed in the same manner as in Example 1.

(Comparative Example 1)

Prepared in the same manner as in Example 1, but instead of citric acid (citric acid) to benzoic acid (benzoic acid) 4.5 parts by weight to complete the polysulfone hollow fiber membrane.

(Comparative Example 2)

Prepared in the same manner as in Example 1, but instead of citric acid (citric acid) lactic acid (lactic acid) to 4.5 parts by weight to complete the polysulfone hollow fiber membrane.

(Comparative Example 3)

Prepared in the same manner as in Example 1, but instead of citric acid (citric acid) maleic acid (maleic acid) to 4.5 parts by weight to complete the polysulfone hollow fiber membrane.

(Comparative Example 4)

Prepared in the same manner as in Example 1, but instead of citric acid (citric acid) to succinic acid (succinic acid) 4.5 parts by weight to complete the polysulfone hollow fiber membrane.

(Comparative Example 5)

Prepared in the same manner as in Example 1, but in order to check the physical properties when no citric acid is used, polysulfone parts by weight, 117 parts by weight of dimethylacetamide, 6 parts by weight of polyethylene glycol, 11 parts by weight of polyvinylpyrrolidone The polysulfone hollow fiber membrane was completed in the state which changed the composition of the solution.

(Comparative Example 6)

Prepared in the same manner as in Example 1, but instead of citric acid (citric acid) toluene sulfonic acid (toluene sulfonic acid) to 4.5 parts by weight to complete the polysulfone hollow fiber membrane.

(Experimental example: physical property measurement experiment)

The physical properties (transmission flow rate, pore size) of the polysulfone porous film prepared by the production method of Examples 1 to 6 and Comparative Examples 1 to 6 were measured, and the results are shown in Table 1 below.

In this experiment, the average pore size was measured using PMI, and the net flux was measured by pressing 1 kgf / cm ² of pure water (20 ° C) using Amiconcell.

division Average pore size
(μm) Pure permeation
(L / m ² hr) Example 1 0.49 7,010 Example 2 0.45 6,330 Example 3 0.38 6,390 Example 4 0.27 3,750 Example 5 0.34 5,950 Example 6 0.13 1,270 Comparative Example 1 0.36 6,780 Comparative Example 2 0.28 5,770 Comparative Example 3 0.23 6,440 Comparative Example 4 0.21 5,730 Comparative Example 5 0.20 4,300 Comparative Example 6 0.42 5,600

Looking at the measurement results of the physical properties of Table 1, it can be seen that in Example 6 the average pore size and pure permeation rate is significantly lower than the other examples and comparative examples, which affects the physical properties when the citric acid content is high can confirm.

In addition, in Comparative Examples 1 to 4, the average pore size and the pure permeation amount were high, and the use of the carboxylic acid-based organic acid was found to be much higher than that of the non-use, and the sulfonic acid-based organic acid, which is one kind of organic acid, was used. Compared to the pore size, the carboxylic acid-based organic acid was confirmed to have a much higher permeate flow rate.

Thus, as can be seen from the above measurement results, the present invention was able to manufacture a porous polysulfone porous film having a high transmission flow rate while having a uniform distribution of pores, the pore size is also pore size from 0.5 ㎛ to 0.1 ㎛ It shows that the size of can be adjusted in various ways, so it can be widely used in water treatment.

The embodiments described above are merely to describe preferred embodiments of the present invention, and are not limited to these embodiments, and various modifications made by those skilled in the art within the technical spirit and claims of the present invention and Modifications or substitution of steps will fall within the technical scope of the present invention.

Claims (5)

In the hollow fiber membrane manufacturing method for producing a hollow fiber membrane after preparing a polymer solution using a polysulfone as a polymer resin,
(A) preparing a polymer solution by mixing a polysulfone (PSF) polymer resin with a carboxylic acid-based organic acid and an additive in a solvent;
(B) stirring the polymer solution at room temperature of 20 ℃ to 25 ℃:
(C) solidifying treatment by spinning with a spinning nozzle in a coagulation bath having a coagulating solution of 45 ℃ to 60 ℃ for the polymer solution subjected to the step (B);
(D) removing the solvent and the non-solvent by immersing the solid product passed through step (C) in a precipitation tank filled with water at 15 ° C. to 25 ° C. for 20 to 24 hours; Including,
In the step (C) to have a condition of humidity of 60% or more to uniformly form the pores of the hollow fiber membrane to be manufactured and to increase the water permeability;
The solvent is dimethyl acetamide (DMAc);
The carboxylic acid-based organic acid is an organic acid having one or more carboxylic acids, but is one selected from lactic acid, succinic acid, citric acid, malonic acid, maleic acid, and benzoic acid;
The additive is a hollow fiber membrane manufacturing method using an organic acid, characterized in that the polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) is used together. The method of claim 1,
In the step (A),
15 to 35 parts by weight of polysulfone (PSF) polymer resin, 3 to 15 parts by weight of carboxylic acid-based organic acid, and 10 to 20 parts by weight of additive based on 100 to 120 parts by weight of a solvent to prepare an organic acid. Hollow fiber membrane manufacturing method using. delete delete The method of claim 1,
Polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP) used as the additive is a polyethylene fiber: polyvinylpyrrolidone = 0.5 ~ 1: hollow fiber membrane using an organic acid, characterized in that the addition of 1 to 1.5 Manufacturing method.

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