KR101368462B1 - Separation Membrane for Water Treatment and Manufacturing Method thereof - Google Patents

Abstract

In the present invention, the support; And an aluminum coating layer formed on the support.
In the water treatment membrane of the present invention, the water treatment separator of the present invention exhibits significantly improved particle removal performance without a decrease in the average pore diameter as compared with a conventional separator in which an aluminum coating layer is not formed.

Description

Separation Membrane for Water Treatment and Manufacturing Method

The present invention relates to a separation membrane for water treatment and a method for manufacturing the same, and more particularly, by coating particles to impart charge to the surfaces of various separation membranes used for conventional water treatment, the particle removal performance is significantly improved by electrostatic adsorption. It relates to a separation membrane for water treatment and a method of manufacturing the same.

The main mechanism for removing contaminants from the membrane is to remove bacteria, viruses and organic contaminants floating in the water by applying a sieve effect, ie removal by particle size. In addition to the removal by the particle size, electrostatic adsorption according to the surface charge of the separation membrane filters the microorganisms in the water. This method has been studied for its high permeability and high particle removal performance compared to a low operating pressure.

For example, Patent Document 1 discloses a technique related to a separator prepared by producing charged alumina nanofibers and then added to glass fibers. However, this technology has a controversial issue such as carcinogenesis in the use of glass fiber and there is a concern that the suitability for use in water treatment process.

In addition, Patent Literature 2 discloses a technique of adding an amine compound during the production of a separator. However, this technology also has a problem using a glass fiber and there is a problem that the product range is not diversified by the compound added in the production of glass fiber.

In addition, in Non-Patent Document 1, there is a method of producing a filter medium in which a polymer solution is charged by electrospinning a polymer solution by corona discharge by a method of applying charge by corona, plasma, or the like during processing. As there is a problem that decreases rapidly with the passage of time, more research on the technology for commercialization is required.

Accordingly, the present inventors have made diligent efforts to overcome the above-mentioned disadvantages of the prior art, and after preparing a coating solution containing aluminum oxide and coating it on the filter media, the filter media is applied to the filter media in an easier way to remove particles. It was confirmed that can be significantly improved and the present invention was completed.

U.S. Pat.No.7,601,262 Patent Publication No. 10-2004-0101723

Korean Journal of Air- Conditions and Refrigeration Engineering, Vol. 20, No. 12 (2008) / pp. 820-824

It is an object of the present invention to provide a membrane for water treatment, in which particle removal performance is remarkably improved by electrostatic adsorption by coating particles that impart charge on the surfaces of various separators used for conventional water treatment.

Another object of the present invention is to provide a method of preparing the separation membrane for water treatment.

Separation membrane for water treatment of the present invention for achieving the above object is a support; And an aluminum coating layer formed on the support.

The aluminum coating layer preferably comprises an aluminum compound and a binder polymer.

The aluminum compound may be aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), sodium aluminate (NaAlO ₂ ), aluminum chloride (AlCl ₃ ), aluminum nitrate (Al (NO ₃ ) ₃ ), aluminum hydroxide (Al (OH) ₃ ) Aluminum salts); Or aluminum isopropoxide (Al (O-CH (CH ₃ ) ₂ ) ₃ ), aluminum ethoxide (Al (O-CH ₂ CH ₃ ) ₃ ), aluminum t-butoxide t-butoxide, aluminum alkoxide such as Al (OC (CH ₃ ) ₃ );

The binder polymer is preferably a polymer containing a hydroxy (-OH), carbonyl (-CO-) or carboxyl (-COOH) functional group. Especially preferably, cellulose acetate is used.

The weight ratio of the aluminum compound and the binder polymer is preferably 40 to 80% by weight of the aluminum compound: 20 to 60% by weight of the binder polymer.

The coating amount of the aluminum coating layer is preferably 5 to 40% by weight based on the weight of the support.

It is preferable that the said support body is a nonwoven fabric.

Method for producing a separator for water treatment of the present invention comprises the steps of preparing a coating solution containing a solid content of the aluminum compound and the binder polymer; And coating and coating the coating solution on a support.

Solid content in the coating solution is preferably composed of 40 to 80% by weight of the aluminum compound, 20 to 60% by weight of the binder polymer.

The separation membrane for water treatment of the present invention exhibits significantly improved particle removal performance without a decrease in the average pore diameter as compared with a conventional separation membrane in which an aluminum coating layer is not formed.

1 is a SEM photograph of the separator prepared in Comparative Example 1,
Figure 2 is a SEM photograph of the separator of the present invention prepared in Example 1.

Separation membrane for water treatment of the present invention support; And an aluminum coating layer formed on the support.

In the present invention, the separation membrane for water treatment refers to a separation membrane for removing microorganisms, ionic salts, etc. present in raw water.

As the support that can be used as the support in the present separation membrane, as long as it can be applied as a conventional water treatment separation membrane having the above average pore size, it can be used as a support constituting the separation membrane of the present invention. For example, in the embodiment of the present invention used a melt-blown nonwoven fabric of polypropylene, but is not limited to this, it is also possible to use a non-woven fabric of another polymer material, not a non-woven support of the other forms It is also possible to apply a support, for example a porous membrane for ultrafiltration or microfiltration, to the support of the invention.

The aluminum coating layer is an aluminum compound is fixed to the binder polymer. The aluminum coating layer is for imparting a positive charge to the membrane for water treatment. The positively charged coating film is effective to adsorb and remove negatively charged microorganisms such as bacteria and viruses in the water and anionic substances in the negatively charged water.

The aluminum compound used for this purpose is aluminum sulfate (Al ₂ (SO ₄ ) ₃ ), sodium aluminate (NaAlO ₂ ), aluminum chloride (AlCl ₃ ), aluminum nitrate (Al (NO ₃ ) ₃ ), aluminum hydroxide (Al An aluminum salt such as (OH) ₃ ); Or aluminum isopropoxide (Al (O-CH (CH ₃ ) ₂ ) ₃ ), aluminum ethoxide (Al (O-CH ₂ CH ₃ ) ₃ ), aluminum t-butoxide t-butoxide, aluminum alkoxides such as Al (OC (CH ₃ ) ₃ ); these may be used alone or in admixture of two or more, particularly preferably aluminum isopropoxide.

The binder polymer in the coating layer is for fixing the aluminum compound on the surface of the support, the binder polymer used for this purpose includes a hydroxy (-OH), carbonyl (-CO-) or carboxyl (-COOH) functional group It is preferable to use a polymer.

Examples of the polymer having a hydroxy, carbonyl or carboxyl functional group include polyethylene glycol, polyvinyl acetate, Polyacrylic acid, polycarboxylic ether Cellulose acetate, and the like. Of these, cellulose acetate is preferably used.

The weight ratio of the aluminum compound and the binder polymer of the aluminum coating layer is preferably 40 to 80% by weight of the aluminum compound: 20 to 60% by weight of the binder polymer. If the content of the aluminum compound is less than 40% by weight, there is a problem in that the positive charge characteristics are not well exhibited. If the content of the aluminum compound exceeds 80% by weight, there is a problem of excessive use of the aluminum compound due to unreacted.

The coating amount of the aluminum coating layer is preferably 5 to 40% by weight based on the weight of the support.

Method for producing a separator for water treatment of the present invention comprises the steps of preparing a coating solution containing an aluminum compound and a binder polymer as a solid; And applying the prepared coating solution on a support and then drying the solvent.

In the first step of the manufacturing method, the aluminum compound, the binder polymer and the content ratio thereof, the support, and the like as solids included in the coating liquid are as described above.

The coating liquid is one in which the solid content is dissolved or dispersed in a suitable solvent. As the solvent for this purpose, alcohols such as chloroform, ethyl acetate, acetone and ethanol, water and the like can be used alone or in a mixture of two or more thereof. Preferably, ethyl acetate, ethanol mixed solvent, or the like is used.

On the other hand, in the coating solution, the content of solids containing the aluminum compound, the binder polymer is preferably 1 to 10% by weight relative to the total coating solution. If the content of the solid content in the coating solution does not reach 1% by weight, there is a problem in that the coating layer is not well formed on the support, and when it exceeds 10% by weight, there is a problem of forming a thick coating layer on the support to prevent pore diameter.

In the method for preparing a separator for water treatment of the present invention, the second step is to apply the prepared coating solution to a support and then dry the solvent.

The coating liquid may be applied by any method conventionally known in the art. For example, the coating solution may be applied to the support by immersing the support in the prepared coating solution for a predetermined time or more. Alternatively, casting can be done by coating or by brush or spray.

After the coating, the solvent in the coating solution is dried to finally prepare a separator of the present invention. Drying of the solvent may also be carried out by conventional methods. For example, natural drying at room temperature, or a suitable drying means such as hot air drying, infrared irradiation may be additionally used.

Hereinafter, the present invention will be described in more detail with reference to Examples. The present invention is described in more detail with reference to the following Examples. However, the scope of the present invention is not limited to these Examples.

≪ Example 1 >

5 g of cellulose acetate (MW 40,000) was added to 990 g of a mixture of ethyl acetate (80 w%) and ethanol (20 w%), followed by mixing using a stirrer. Then, 5 g of aluminum isopropoxide was added to the mixture, followed by stirring to disperse the coating solution. Ready.

The coating solution was immersed in a coating bath containing the coating solution for 5 minutes by immersing a polypropylene nonwoven fabric (Woongjin Chemical, maximum pore diameter 8.3㎛, average pore size 4.9㎛, basis weight 45g / m2, thickness 300㎛) for 5 minutes and then removing it from the coating bath. After coating on a non-woven fabric, and then dried at room temperature to prepare a membrane for water treatment.

<Example 2>

In preparing the coating solution, except that 985g of ethyl acetate and ethanol mixture solution, and 10g of aluminum isopropoxide, the coating solution was prepared, coated and dried in the same manner as in Example 1 to prepare a membrane for water treatment.

<Example 3>

In preparing the coating solution, except that 980g of ethyl acetate and ethanol mixture solution and 15g of aluminum isopropoxide were prepared, the coating solution was prepared, coated and dried in the same manner as in Example 1 to prepare a membrane for water treatment.

<Example 4>

A coating solution was prepared, coated and prepared in the same manner as in Example 1, except that a polypropylene nonwoven fabric (Woongjin Chemical, a maximum pore diameter of 8.0 μm, an average pore diameter of 2.03 μm, basis weight of 90 g / m 2, thickness of 600 μm) was used as a support. It was dried to prepare a membrane for water treatment.

<Example 5>

In preparing the coating solution, except that 985g of ethyl acetate and ethanol mixture solution, 10g of aluminum isopropoxide, the coating solution was prepared, coated and dried in the same manner as in Example 4 to prepare a membrane for water treatment.

<Example 6>

In preparing the coating solution, except for using ethyl acetate, ethanol mixture 980g, aluminum isopropoxide 15g, the coating solution was prepared, coated and dried in the same manner as in Example 4 to prepare a membrane for water treatment.

&Lt; Comparative Example 1 &

A coating solution was prepared, coated and dried in the same manner as in Example 1, except that 995 g of an ethyl acetate and ethanol mixture was used without using aluminum isopropoxide to prepare a membrane for water treatment.

Comparative Example 2

A coating solution was prepared, coated and dried in the same manner as in Example 4, except that 995 g of an ethyl acetate and ethanol mixture was used without using aluminum isopropoxide to prepare a membrane for water treatment.

<Evaluation>

1. Point and average pore size

In order to determine the basic properties of the membranes prepared in Examples 1 to 6 and Comparative Examples 1 to 2, the pore size and the average pore size were measured using a separator pore size evaluator (Maker: PMI, model: CFP-1200-AE).

The maximum pore diameter, average pore diameter, minimum pore diameter and pore size distribution were determined by measuring the change in flow rate compared to the air pressure applied to the filtration membrane (ASTM E1294).

After wetting the pore size of the filtration membrane completely using a liquid having a known surface tension, the pore size was determined by measuring the pressure when the flow rate was most generated by applying air pressure (ASTM F316).

2. Particle Removal Performance

In order to confirm the improved particle removal performance according to the charge is measured using a filter tester-particle removal analyzer (Maker: TSI, model: 8130, condition: air flow rate-85lpm, 0.26㎛ NaCl particle generation) instrument.

3. Coating amount

In order to measure the coating amount of the cellulose acetate and aluminum salt on the support, the weight of the unit area was measured by an electronic balance.

The above evaluation results of the separator prepared in Examples and Comparative Examples are summarized in Table 1 below.

division Coated Media Al concentration
(%) Gun point
(psi) Average pore size
(탆) Basis weight
(g / m 2) Particle Removal Performance
(%) Example 1 PP M / B 45g / ㎡ 0.5 0.82 4.79 48.71 90.22 Example 2 PP M / B 45g / ㎡ 1.0 0.81 3.64 52.37 92.54 Example 3 PP M / B 45g / ㎡ 1.5 0.76 4.54 55.60 95.82 Example 4 PP M / B 90g / ㎡ 0.5 0.81 2.20 97.32 99.22 Example 5 PP M / B 90g / ㎡ 1.0 0.94 2.06 104.74 99.84 Example 6 PP M / B 90g / ㎡ 1.5 1.36 2.89 112.11 99.89 Comparative Example 1 PP M / B 45g / ㎡ 0 0.84 4.91 46.35 87.00 Comparative Example 2 PP M / B 90g / ㎡ 0 0.81 3.62 92.70 97.84

As can be seen in Table 1, compared with Comparative Examples 1 to 2 in which the aluminum coating layer is not formed, the polypropylene support having the aluminum coating layer may have a result of improving particle removal performance. In addition, it can be seen that the higher the content of the aluminum compound in the coating solution is 0.5 to 1.5%, the higher the particle removal performance. On the other hand, the average pore size of Examples 1 to 6 in which the aluminum coating layer was formed was confirmed to decrease slightly from Comparative Examples 1 to 2. It was confirmed that the average pore size was increased when the aluminum compound particles were contained in the coating solution at 1% and the average pore size was increased to 1.5%.

In addition, as can be seen in Comparative Example 2, Examples 4 to 6 it was confirmed that the bubble point increases when the aluminum compound content to the coating liquid increases. Thereby, although the maximum pore seemed to gradually decrease, Comparative Example 1 and Examples 1-3 did not show this tendency. Thus, the tendency toward bubbling appears somewhat different depending on the basis weight of the support.

In Example 6, although the average pore size was slightly changed according to the addition of the aluminum compound, 0.2 μm NaCl particles were removed up to 99.89% at the average pore size of 3 μm. It was confirmed that the particle removal performance by the improved.

1 is a SEM photograph of the separator prepared in Comparative Example 1, Figure 2 is a SEM photograph of the separator of the present invention prepared in Example 1. SEM photographs were obtained (using model SNE-3000M instrument). 1 and 2, in FIG. 2, the aluminum compound is coated on the support surface of FIG. 1 in the form of particles to cover the support surface.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be construed as limiting the scope of the invention as defined by the appended claims. .

The separation membrane for water treatment prepared by the present invention can be used as filter media such as viruses, microorganisms such as bacteria, heavy metal removal and pharmaceutical, food, drinking water, manufacturing and RO pretreatment.

Claims (13)

A support; In the separation membrane for water treatment comprising; and an aluminum coating layer formed by applying a coating liquid containing an aluminum compound and a binder polymer as a solid on the support and then dried.
The aluminum compound is aluminum isopropoxide (Al (O-CH (CH ₃ ) ₂ ) ₃ ), aluminum ethoxide, Al (O-CH ₂ CH ₃ ) ₃ ) and aluminum t-butoxide At least one aluminum alkoxide selected from the group consisting of aluminum t-butoxide, Al (OC (CH ₃ ) ₃ ),
The binder polymer is water separation membrane, characterized in that at least one selected from the group consisting of polyethylene glycol, polyvinylacetate, polyacrylic acid, polycarboxylic ether and cellulose acetate. delete delete delete delete The separator of claim 1, wherein the weight ratio of the aluminum compound to the binder polymer is 40 to 80% by weight of the aluminum compound: 20 to 60% by weight of the binder polymer. The separation membrane of claim 1, wherein the coating amount of the aluminum coating layer is 5 to 40 wt% based on the weight of the support. The separation membrane for water treatment according to claim 1, wherein the support is a nonwoven fabric. Aluminum isopropoxide (Al (O-CH (CH ₃ ) ₂ ) ₃ ), aluminum ethoxide, Al (O-CH ₂ CH ₃ ) ₃ ) and aluminum t-butoxide as aluminum compounds (aluminum t-butoxide, Al (OC (CH ₃ ) ₃ ) One or more aluminum alkoxide and binder polymers selected from the group consisting of polyethylene glycol, polyvinylacetate, polyacrylic acid, polycarboxylic ether and cellulose acetate Preparing a coating solution comprising at least one polymer selected from solids;
Coating the coating solution on a support; And
Drying the coated support; Method of producing a separator for water treatment comprising a. The method of claim 9, wherein the solid content in the coating solution is 40 to 80% by weight of the aluminum compound, 20 to 60% by weight of the binder polymer. delete delete 10. The method of claim 9, wherein the binder polymer is cellulose acetate.

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