KR101875812B1 - An ion-exchange membrane and porous substrate for water treatment and manufacturing method of it - Google Patents

Abstract

The present invention relates to an ion exchange membrane for water treatment, in particular, an ion exchange membrane for ED (Electrodialysis) and RED (reverse electrodialysis), and particularly relates to an ion exchange membrane using an organic / inorganic hybrid porous microporous porous support having a low manufacturing cost and excellent mechanical properties and chemical stability membrane. The present invention relates to a process for preparing an electrolyte membrane for isolating an anode and a cathode from each other in the production of an electrodialysis system, comprising the steps of: preparing a polyolefin which is a base material of a porous support; A surface-treated nanoparticle inorganic filler which is uniformly dispersed in the polyolefin membrane using the polyolefin membrane as a dispersion medium; There is provided an ion exchange membrane for water treatment in which the cation conductor is homogeneously impregnated into a porous base membrane in the form of a monoaxially or biaxially stretched film in which the nanoparticle inorganic filler is uniformly dispersed.

Description

[0001] The present invention relates to an ion exchange membrane for water treatment using a porous base membrane and a manufacturing method thereof,

The present invention relates to an ion exchange membrane for water treatment, particularly an ion exchange membrane for ED (Electrodialysis) and RED (Reverse Electrolysis). The present invention provides an ion exchange membrane using an organic / inorganic composite microporous support having a low manufacturing cost and excellent mechanical properties and chemical stability.

Ion exchange membranes are used in fields such as fuel cells, diffusion dialysis, redox flow cells, water treatment, and desalination of seawater. Ion exchange membranes are attracting worldwide attention because they are relatively simple to manufacture, have excellent selectivity for specific ions, and have a wide range of applications, making them especially important for reducing environmental pollution by reducing fossil raw material usage.

The ion exchange membrane as described above can selectively separate cations and anions in the aqueous solution, and thus can be used as a fuel cell, electrodialysis, electrodialysis for water decomposition for acid and base recovery, diffusion dialysis for recovering acid and metal species from acid waste, Process. In recent years, the application range of ion exchange membranes has been expanding as high performance ion exchange membranes have been developed.

Such ion exchange membranes must have high selectivity and require low permeability of solvent and non-ionic solutes, low resistance to diffusion of selected permeate ions, high mechanical strength and chemical resistance. Such an ion exchange membrane is required to have excellent mechanical strength and durability. Methods commonly used to meet such demands include a method of producing a hybrid composite membrane by adding an inorganic substance, a hot pressing method of hot pressing the catalyst mixture, and a method of adding a hardening agent. In the hybrid composite membrane manufacturing method, if the swelling phenomenon of the membrane is continued, there is a gap between the inorganic material and the polymer membrane, and the ion exchange ability can not be exhibited properly. The hot press method in which the catalyst mixture is heated and pressed has a disadvantage in that the catalyst layer dissolves over time. Also, the method of adding a curing agent also has a disadvantage that the curing agent dissolves over time. It has been desired to develop an ion exchange membrane having high durability and excellent mechanical properties due to the problems described above.

Currently, commercialized ion exchange membranes used in fuel cell membranes, electrode membranes, etc. are sulfonated polystyrene, Nafion _TM (hereinafter referred to as "Nafion") manufactured by Du Pont, and the like. However, when the sulfonated polystyrene is dried, it is broken down due to an increase in brittleness, which makes it difficult to form into a thin film or a composite film, and has a disadvantage in that mechanical stability is poor when it is processed into an electrode.

In order to improve such disadvantages, there is a method of controlling the sulfonation ratio of polystyrene or a method of increasing the thickness of the membrane. At this time, the membrane resistance is increased and the ion exchange ability of the membrane is remarkably decreased, When the system is manufactured, the volume is increased and the space is limited.

In addition, Nafion has been used as an ion exchange membrane due to its high conductivity and chemical stability as a fluorine-based material. However, Nafion is very expensive due to the fluorine compound contained therein and its use at a high temperature is limited. In fact, expensive ion exchange membranes such as Nafion and the like have a great effect on the actual battery operation and are pointed out as a cause of increasing the manufacturing cost of the battery.

The unit price of the perfluorosulfonic acid ion exchange membrane such as Nafion _TM is as high as about one million Yuan / m ² , which is one of the problems to be solved. In this study, we have studied various nonfluorinated ion exchange membranes with low cost. Especially, we have investigated the effect of nonionic fluorinated ion exchange membranes such as SPAES (sulfonated polyaryleneether sulfone), SPEEK (sulfonated polyetherether ketone), PBI (Polybenzimidazole), SPSf (sulfonated polysulfone) Polymers have been extensively studied.

Non-fluorinated polymeric materials have been tested for the possibility of new materials by controlling various factors such as introduction of various functional groups, arrangement of polymer chains, and control of molecular weight. However, most of the materials have limited limitations in practical applications due to their low chemical / physical stability compared to their excellent electrical performance. Therefore, various methods have been proposed to improve the performance of the polymer material. However, the results of these efforts show low ion selectivity and low durability.

Korean Patent No. 10-1144975

As described above, as a non-fluorine-based ion exchange membrane material, resins having excellent mechanical properties such as polybenzimidazole, polyphosphazene, PEEK, polysulfone, polyimide, polyether imidazole and polyphenylene sulfide sulfone are mixed, But the cost of membranes made of these materials is still high and the method of introducing an ion exchanger through the functionalization after the production of the membrane is that the physical properties of the membrane surface are lowered due to the reaction during the introduction of the functionalization, There was a problem that was vulnerable. Accordingly, there is a disadvantage that a drug such as a plasticizer is used in order to improve durability, and a new method for improving cost and mechanical properties is required.

Accordingly, the present invention provides a method for preparing an electrolyte membrane for separating an anode and a cathode from each other in the production of an electrodialysis system, comprising: preparing a polyolefin which is a base material of a porous support; A surface-treated nanoparticle inorganic filler which is uniformly dispersed in the polyolefin membrane using the polyolefin membrane as a dispersion medium; The present invention provides an ion exchange membrane for water treatment in which the cation conductor is homogeneously impregnated in a porous support in which the nanoparticle inorganic filler is uniformly dispersed.

According to the present invention, the micropores formed on the polyolefin membrane and biaxial stretching ratio lower than the stretch ratio of a conventional 100% PE resin film are secured to ensure physical strength, and an ion exchange membrane impregnated with a cation conductor .

According to the ion exchange membrane for water treatment of the present invention, the production cost is low for a perfluorosulfonic acid ion exchange membrane such as the conventional Nafion. Also, the ion exchange membrane of the present invention is relatively excellent in physical / chemical characteristics because it is composed of a polyolefin-based organic-inorganic hybrid membrane in which inorganic filler such as nanosilica particles are uniformly dispersed while the contrast price is low. According to the above-described structure, it has high mechanical strength (tensile strength, puncture strength), and it has acid resistance and refractory characteristics and maintains high effect even in long term stability. Also, the ion exchange effect by the cation conductor adsorbed on the porous base membrane and the movement of the ions through the micropores can be freely controlled, so that the selective ion permeability can be expected by controlling the pore size to block specific ions at a physical size.

1 is a photograph of the porous support prepared in Comparative Example 1, which is a method of producing a polymer electrolyte membrane,
2 is a photograph of an electrolyte membrane produced by the method of the embodiment,
3 is a SEM photograph of the porous support prepared in Example,
4 is a more enlarged SEM photograph of the porous support prepared in the example.
5 is a cross-sectional SEM photograph of the porous support prepared in the example.

The present invention relates to an ion exchange membrane using an organic / inorganic composite microporous porous support having a low manufacturing cost and excellent mechanical properties and chemical stability as an ion exchange membrane for water treatment, particularly, ED (Electrodialysis) and RED (Reverse Electrolysis) .

The present invention provides an ion exchange membrane for water treatment, comprising: a porous base membrane comprising a polyolefin base material (base material) and a nanoparticle inorganic filler dispersed in the polyolefin base material; and a cationic and anionic conductor And an ion exchange membrane for water treatment. The ion exchange membrane may be formed to have a thickness of 10 to 100 mu m.

The cation conductor

(1), wherein in Formula 1,

A and A 'are one selected from -S-, -SO ₂ -, -NH-, -C (CH ₃ ) ₂ - and -C = O-,

B is -O-, -SO ₂ -, and -C = O- or -C (CF _{3) 2,}

X is sodium or potassium,

k = n + mk, and n / (n + m) is preferably 0.001 to 1.

The polymer represented by the formula (1) has an intrinsic viscosity of not less than 0.1 as measured on N-methyl-α-pyrrolidinone (NMP), and an intrinsic viscosity of not less than 0.8 and not more than 2.5 as measured on NMP Can be used.

In the present invention, the cationic conductor solution may contain 10 to 30% by weight of a polymer having a cation-exchange group represented by the general formula (1) in the total solution.

Examples of such cationic conductors include sulfonate polyarylene ether sulfone (SPAES) copolymer having a degree of sulfonation of 30 to 70%, sulfonated polyimide, sulfonate polybenzimidazole a sulfonated polybenzimidazole, a sulfonated polysulfone sulfonated polystylene, a sulfonated polyether ketone, a sulfonated polyetheretherketone, or a mixture thereof have.

The nanoparticle inorganic filler is at least one selected from the group consisting of silica (SiO ₂ ), TiO ₂ , Al ₂ O ₃ , zeolite, AlOOH, BaTiO ₂ , talc, Al (OH) ₃ and CaCO ₃ Preferably hydrophobicized and hydrophilized surface-treated nanomaterials of spherical particles having an average particle diameter of 10 nm-6 占 퐉, and more preferably the spherical particle size is 50 nm-1 占 퐉. The addition ratio of the surface-treated nanoparticle inorganic filler is preferably 10 to 50 wt% based on the total weight of the entire porous support. If the inorganic filler is added in an amount of 50% or more based on the total weight of the nanoparticle, mechanical strength of the porous support decreases. If less than 10% of the inorganic filler is added, the inorganic filler does not work and pore formation is difficult.

The hydrophobic surface-treated nanoparticle silica (SiO2) has various sizes and shapes according to the production process. As shown in the SEM image of the present invention, the spherical type is the most suitable. According to the sol-gel synthesis method as described above, it is possible to produce a nano-sized surface-treated particle having a small average particle size and a narrow particle size distribution.

The surface of the silica (SiO2) is preferably coated with hydrophobic (linear hydrocarbon) molecules on its surface. Since the silica itself has a hydrophilic property, it can be seen that a nanoparticle spherical type silica coated with a straight chain hydrocarbon molecule is suitable for improving compatibility with a polyolefin resin originally hydrophobic.

That is, the nanoparticle inorganic filler is spherical nanosilica having a size of 10 nm to 600 nm, and the surface is preferably treated with ethylene. At this time, the nanoparticle inorganic filler is preferably contained in an amount of 10 to 50% by weight based on the total weight of the ion exchange membrane for water treatment. Nanoparticle inorganic filler has relatively good physical / chemical properties and thus has high mechanical strength (tensile strength, puncture strength) and acid resistance and fire resistance, so that it can maintain high effect even in long term operation .

Preferably, the porous base membrane is manufactured by biaxial stretching, has an air permeability of less than 70 to 180 seconds, a porosity of 40 to 80%, and a pore diameter of 0.1 to 50 μm. The diameter of the pores may be adjusted according to the size of the ions required for selective permeation.

The polyolefin membrane, which is the base material of the porous support, may be selected from the group consisting of high density polyethylene (HDPE), ultra high molecular weight polyethylene (UHMWPE), polypropylene (PP), and polymethylpentene In particular, the polyolefin membrane, which is the base material of the porous support, may be made of ultra high molecular weight polyethylene (UHMWPE) in a ratio of the total weight of the porous support film 5-50%, high density polyethylene (HDPE) in an amount of 5-20% of the total weight and 5-20% of the total weight of polypropylene.

The high molecular weight polyethylene (UHMWPE) has a weight average molecular weight of 100-500,000 and a molecular weight of 3-6 (dispersion). The high density polyethylene (HDPE) has a weight average molecular weight of 30-70 (Degree of dispersion) of from 3 to 6, and the polypropylene preferably has a weight average molecular weight of from 10 to 20,000 and a molecular weight of from 3 to 6 (degree of dispersion).

When the ultra high molecular weight polyethylene (UHMWPE) or the high density polyethylene resin and the polypropylene resin are melt-kneaded in an extruder as described above, a small amount of a compatibilizer may be added, and a plasticizer, a processing agent ) Or an antioxidant may be added. In particular, it has been found that the plasticizer or the processability-improving agent is required to improve compatibility with each of the high-density polyethylene, polypropylene and polymethylpentene resin, which is made of an ethylene oligomer-based material.

The method for producing an ion exchange membrane for water treatment comprises: preparing a nanoparticle inorganic filler and a polyolefin matrix (s100); Mixing the nanoparticle inorganic filler and the polyolefin base material with paraffin oil (s200); A step of removing fine bubbles by vacuum defoaming (s300); A melt-kneading and discharging step (s400) at 150-300 占 폚; (S500) forming the melt-kneaded discharge product from a casting roll at 50-100 DEG C into a base sheet; Biaxially stretching the base sheet (s600); Immersing the base sheet in a solvent to remove paraffin oil (s700); Immersing the base sheet in the cation conductor solution or applying the cation conductor solution to the base sheet (s800); And impregnating the base sheet with a cation conductor (s900).

As described above, in the nanoparticle inorganic filler and polyolefin matrix preparation step (s100), the nanoparticle inorganic filler is spherical nanosilica having a size of 10 nm to 600 nm, and the surface is preferably treated with ethylene, and the nanoparticle inorganic filler And the polyolefin matrix preparation step (s100), the polyolefin matrix is preferably an ultra-high-molecular-weight polyethylene having a molecular weight of from 1,110,000 to 1,800,000, a high-molecular-weight polyethylene having a molecular weight of 30,000 to 400,000, or a mixture thereof.

In addition, it is preferable that the step (s600) of biaxially stretching the base sheet is 80-150% stretching in both the transverse direction and the longitudinal direction at a temperature of 100-200 占 폚. Of course, it is also applicable to apply uniaxial stretching.

In order to obtain higher mechanical properties, the base sheet is immersed in a solvent to remove paraffin oil (s700). After sintering, the base sheet is shrunk by 5 to 20% in each of the transverse and longitudinal directions and then shrunk by 3-10% And a second elongating step (s710) of holding and heat setting (Heat Set).

In the step (s800) of immersing the base sheet in the cation conductor solution or applying the cation conductor solution to the base sheet,

The cation conductor solution is prepared by adding 4,4'-dichlorodiphenylsulfone, 4,4'-biphenol, disulfonated dichlorodiphenylsulfone, K ₂ CO ₃ and NMP, and toluene at 80 to 150 ° C. for 30 minutes, A monomer dissolving step (s810) for stirring for 2 hours; Raising the temperature to 150 to 180 ° C, refluxing with toluene for 3-6 hours to remove water as a reaction product (s820); Further increasing the temperature to 190 to 250 DEG C to completely remove the remaining toluene from the dean-stark trap and reacting for 20 to 48 hours (s830); Diluting the reaction solution with water, pouring it into water to precipitate in the form of swollen fiber and filtering (s840); Drying (s850) a sulfonated polyarylene ether sulfone copolymer having a sulfonation degree of 30 to 70%; (S860) dissolving the sulfonate polyarylene ether sulfone copolymer in an organic solvent such as dimethylacetamide (DMAc) or NMP at a temperature of 50 to 90 占 폚. The tensile strength of the prepared porous support is 1000 to 2000 kgf / cm 2.

1. Example

1-1. Porous base membrane manufacturing

Spherical nanosilica coated on ethylene surface 20wt% average particle diameter and kinematic viscosity 40cSt (based on 40 ℃) Liquid paraffin oil 65%, ultra high molecular weight polyethylene (Mw = 1.5 million) 20wt%, high molecular weight polyethylene (Mw = 350,000) 20 wt%.

Hydrocarbon surface treated nanosilica particles were mixed in liquid paraffin oil at a ratio of 10 to 50% and the nanosilica particles were uniformly dispersed using a high speed mixing mixer. After the vacuum defoaming process, microbubbles formed during the mixing process were removed.

Kneaded and discharged at 190 to 230 ° C using a twin screw extruder equipped with a T-die having a width of 350 mm. At this time, the feed content was controlled so that the inorganic filler content was 51.4% based on the weight of the final porous base membrane.

The melt-kneaded material extruded through the T-die was cooled and solidified at room temperature through a casting roll at 60 ° C. The thickness of the sheet was adjusted to 1 to 2 mm.

Subsequently, the extruded porous base membrane was stretched to 100% in the transverse direction and 100% in the longitudinal direction using a biaxial stretching machine heated to 120 ° C to produce a film.

Then, the stretched film was immersed in methylene chloride at 40 DEG C for 1 hour to remove the liquid paraffin oil.

The residue was then dried at room temperature to remove residual solvent. Then, 5% shrinkage after 10% stretching in the transverse direction and 5% shrinkage after 10% stretching in the longitudinal direction through the biaxial stretching machine were carried out and the heat set operation was carried out by holding for 30 seconds.

1-2. Preparation of sulfonated polyarylene ether sulfone copolymer having 40% of sulfonation degree

A gas inlet, a thermometer, a Dean-Stark trap, a condenser and a stirrer were installed in a 100 ml round-bottom flask equipped with a stirrer, and air and impurities were removed for a few minutes in a nitrogen atmosphere. Then, 4,4'-dichlorodiphenylsulfone , 3.7242 g of 4'-biphenol (hereinafter referred to as "BP"), 3.9301 g of disulfonated dichlorodiphenylsulfone, 3.1787 g of K2CO3 and 44.4 ml of NMP and 22.2 ml of toluene (NMP / toluene = 2/1 V / And the monomer was dissolved while stirring at 80 DEG C or higher for 1 hour.

Thereafter, the temperature of the reaction solution was raised to 160 ° C., refluxed with toluene for 4 hours to remove water as a reaction product, and then the temperature was raised to 190 ° C. to completely remove the residual toluene from the Dean-Stark trap, . When the reaction was completed, the reaction solution was diluted with NMP and filtered, and then poured into water to precipitate in the form of swollen fiber and filtered. Thereafter, the obtained reaction product was dried in a vacuum dryer at 120 ° C for 24 hours to obtain a sulfonated polyarylether sulfone (SPAES) as a sulfonated polymer copolymer.

1-3. The sulfonated polyarylene ether sulfone (SPAES) copolymer having a degree of sulfonation of 40% as prepared above was dissolved in dimethylacetamide (DMAc) at 60 ° C. The ionic conductor solution prepared in the porous base membrane was applied and then uniformly impregnated through a reduction / pressure process to prepare an electrolyte membrane

2. Comparative Example 1

The commercialized Neosepta (trade name) cation exchange membrane (CMX) was washed with deionized water and the electrolyte membrane was evaluated using the above method.

3. Comparative Example 2

The commercially available Neosepta (trade name) anion exchange membrane (AMX) was washed with deionized water and the electrolyte membrane was evaluated using the above measurement method.

4. Comparative Example 3

The ion conductor prepared in the above example was uniformly impregnated with the ion conductor in the same manner as in the example of the embodiment, except that the silica particles were removed from the ion membrane to prepare an electrolyte membrane.

[Test Measurement Method]

1. Ventilation

Prepare the sample at 30mm * 30mm and measure the time that 100ml air passes through TOYOSEIKI airflow meter.

2. Tensile strength

The porous support sample is cut in the MD and TD directions to conform to the specimen shape of the ASTM D standard. Bite the specimen to a jig on a universal tensile testing machine (UTM), and pull it at a constant speed to measure the stress (N) applied until fracture occurs.

Remarks thickness
(탆) Transmittance
(Permeability)
(sec) The tensile strength
Break Strength
(kgf / cm²) Break longation (%) MD TD MD TD Neosepta 170 - 370 20.6 Comparative Example 1 19.0 322.8 1611 1041 70.3 106.8 Example 1 17.9 274.9 1725 1035 60.7 120.3

3. Porosity (%)

The porous support sample is cut to a certain size and then weighed with an electronic scale. Density is measured using a density gradient method in the absence of pores (eg after cooling after melting). Then, the theoretical weight of the film weight and the cut size is calculated by the measured density value, and then the porosity is calculated.

4. Puncture Strength

Prepare a porous support sample of 100 mm * 50 mm. Measure the force at the point where the porous support sample is pierced by applying force to the stick by using a KATOTECH pounding strength meter.

5. Measurement of water absorption rate

In order to measure the water absorption rate of the electrolyte membrane prepared in the Examples and Comparative Examples, the electrolyte membrane was washed several times with deionized water, and the washed polymer electrolyte membrane was immersed in deionized water for 24 hours, And the weight was measured (Wwet). Subsequently, the same membrane was again dried in a vacuum dryer at 120 ° C for 24 hours and then weighed again (Wdry). The water absorption rate was calculated by the following formula (1).

<Formula 1>

Water uptake (%) = [(Wwet-Wdry) / Wdry] x 100

6. Measurement of dimensional stability

The dimensional stability was measured in the same manner as in the measurement of the water absorption rate, but instead of measuring the weight, the area change of the membrane was measured and then calculated by the following equation (2).

<Formula 2>

Dimensional change ratio (%) = [(membrane area wet-membrane area dry) / membrane area dry] x 100

7. Ion conductivity measurement

The ionic conductivity of the nanocomposite electrolyte membranes prepared in Examples 1 to 4 and Comparative Example 1 was measured using a measuring instrument (VSP-300 Impedance / Gain-Phase analyzer, Neoscience Co., Ltd.). At this time, the impedance spectrum was recorded from 10 MHz to 10 Hz, and the ion conductivity was calculated by the following equation (3).

<Formula 3>

Ion conductivity (S / cm); ? = (1 / R) x (L / A)

(Where R is the measurement resistance (?), L is the length (cm) between the measurement electrodes, and A is the cross-sectional area (cm 2) of the electrolyte membrane produced.

Electrolyte membrane Water Absorption Rate (%) Ion conversion rate
(meq./g) Film thickness
(탆) Ion conductivity
(mS / cm) Membrane resistance
(W cm ² ) Transport No. Transition time (sec) Comparative Example 1 26.21 1.60 165 5.111 3.228 0.980 9.532 Comparative Example 2 21.08 1.40 135 4.16 3.24 0.97 9.42 Comparative Example 3 30.45 0.76 74 3.116 2.375 0.900 10.068 Example 32.65 1.05 76 6.343 1.198 0.970 9.113

8. Molecular weight measurement

In order to measure the molecular weight of polyethylene, it was dissolved in 1,2,4-trichlorobenzene for at least 8 hours and flowed at a rate of 0.92 ml / min.

Gel Permeation Chromatography (GPC) used was CPCV 2000 from Waters.

Number-average molecular weight (Mn)

Weight-average molecular weight (Mw)

Hi: The detector signal height at the baseline of the retention volume (Vi)

Mi; The molecular weight of the polymer fraction at the retention volume (Vi)

n: number of data

As shown in Table 1, the ion exchange membrane for water treatment (Example 1) according to the present invention had excellent physical properties having a high ion conductivity (6.343 mS / cm) even at a low film thickness (1.198 W cm 2).

That is, according to the ion exchange membrane for treatment of the present invention, the manufacturing cost is low compared to the conventional fluorine ion exchange membrane such as Nafion. Further, the ion exchange membrane of the present invention is composed of a polyolefin-based organic-inorganic hybrid membrane in which the inorganic filler such as nanosilica particles are uniformly dispersed while being inexpensive, and thus the physical / chemical properties are relatively excellent. According to the above-described structure, it has high mechanical strength (tensile strength, puncture strength), and it has acid resistance and refractory characteristics and maintains high effect even in long term stability. Also, the ion exchange effect by the cation conductor adsorbed on the porous base membrane and the movement of the ions through the micropores can be freely controlled, so that the selective ion permeability can be expected by controlling the pore size to block specific ions at a physical size.

The present invention is merely one example of various embodiments and it is an object of the present invention to allow a person having ordinary skill in the art to easily carry out the present invention. It is clear that it is not. Accordingly, the scope of protection of the present invention should be construed according to the following claims, and all technical ideas which fall within the scope of equivalence by alteration, substitution, substitution, Range. In addition, the drawings are made for clarification of the configuration, and are made to be exaggerated or reduced in size.

Claims (15)

In the ion exchange membrane for water treatment,
A porous base membrane in the form of a monoaxially or biaxially stretched film comprising a polyolefin matrix (base material) and a nanoparticle inorganic filler dispersed in the polyolefin matrix;
And a cation conductor and an anion conductor adsorbed on the porous base membrane,
The nanoparticles inorganic filler include silica _{(SiO 2), TiO 2,} Al 2 O 3, zeolite _{(zeolite), AlOOH, BaTiO 2} , talc (Talk), Al (OH) 3, and CaCO ₃ of one or more nano-inorganic material selected from the group consisting of ego,
Wherein the nano-inorganic material is subjected to hydrophobic surface treatment with spherical particles having an average particle diameter of 10 nm to 600 nm.
delete delete delete The method according to claim 1,
Wherein the nanoparticle inorganic filler comprises 10 to 50 wt% of the total weight of the ion exchange membrane for water treatment.
The method according to claim 1,
Wherein the porous base membrane is prepared by uniaxially or biaxially stretching, and has a porosity of 40 to 80% and a pore diameter of 10 to 50 탆.
The method according to claim 1,
Wherein the polyolefin matrix is an ultrahigh molecular weight polyethylene having a molecular weight of 1 million to 5,000,000 or a high molecular weight polyethylene having a molecular weight of 30,000 to 700,000 or a mixture thereof.
In the method for producing an ion exchange membrane for water treatment,
i) preparing nanoparticle inorganic filler and polyolefin matrix (s100);
ii) mixing the nanoparticle inorganic filler and the polyolefin matrix with paraffin oil (s200);
iii) a step of removing fine bubbles by vacuum defoaming (s300);
iv) melt-kneading and discharging at 150-300 ° C (s400);
v) forming (s500) the melt-kneaded discharge from a casting roll at 50-100 DEG C into a base sheet;
vi) step (s600) of biaxially stretching and fixing the base sheet;
vii) dipping the base sheet in a solvent to remove paraffin oil (s700);
viii) immersing the base sheet in the cation conductor solution or applying the cation conductor solution to the base sheet (s800);
ix) impregnating the base sheet with a cation conductor (s900);
Lt; / RTI &gt;
The nanoparticles inorganic filler include silica _{(SiO 2), TiO 2,} Al 2 O 3, zeolite _{(zeolite), AlOOH, BaTiO 2} , talc (Talk), Al (OH) 3, and CaCO ₃ of one or more nano-inorganic material selected from the group consisting of ego,
Wherein the nano-inorganic material is subjected to hydrophobic surface treatment with spherical particles having an average particle diameter of 10 nm to 600 nm. &Lt; RTI ID = 0.0 &gt; 11. &lt; / RTI &gt;
9. The method of claim 8,
In the nanoparticle inorganic filler and polyolefin matrix preparation step (s100)
Wherein the nanoparticle inorganic filler is spherical nanosilica having a size of 10 nm to 600 nm and the surface is coated with ethylene.
9. The method of claim 8,
In the nanoparticle inorganic filler and polyolefin matrix preparation step (s100)
Wherein the polyolefin matrix is an ultrahigh molecular weight polyethylene having a molecular weight of 1,100,000 to 1,800,000 or a high molecular weight polyethylene having a molecular weight of 30,000 to 400,000 or a mixture thereof.
delete 9. The method of claim 8,
After the base sheet is immersed in a solvent to remove paraffin oil (s700), the base sheet is stretched 5-20% in each of the transverse and longitudinal directions, shrinked 3-10%, and then held for 20-120 seconds, And a second elongating step (S710) for forming the porous base membrane.
9. The method of claim 8,
Wherein the porous base membrane has a tensile strength of 1000 to 2000 kgf / cm &lt; 2 &gt;.
delete delete

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