KR20100021265A - Manufacturing method of ion exchange solution composion for electrod using polystyrene resins or their derivatives and method of ion exchange membrane containing their solution - Google Patents

Abstract

PURPOSE: A composition for ion exchange liquid for electrode using polystyrene resin or derivates and a manufacturing method of an ion exchange film including the same are provided to reduce manufacturing costs of the ion exchange film and to replace the expensive ion exchange film. CONSTITUTION: A manufacturing method of an ion exchange film for CDI includes the following steps: manufacturing ion exchange liquid; coating the ion exchange liquid on a mesh net; post-processing the coated ion exchange film; and drying the ion exchange film. The ion exchange film adds a positive ion exchange group with mixed acid of sulfuric acid or chlorosulfonic acid / sulfuric acid on polysterene-based resin.

Description

Manufacturing method of ion exchange solution composion for electrod using polystyrene resins or their derivatives and method of ion exchange membrane containing their solution}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of high efficiency ion exchange membranes for CDI electrodes using polystyrene (hereinafter referred to as PS), and more particularly to the removal of ionic substances such as calcium, magnesium and nitrate in groundwater and simplified feed water. The present invention relates to an ion exchange solution for electrodes and a method for producing a membrane using the same.

Most of the ion exchange membranes currently used are those in which a cationic functional group such as sulfonic acid group is introduced into a fluorine-based polymer resin having excellent heat resistance, and are manufactured and commercialized by DuPont, Dow Chemical, Asahi Chemical of Japan, and Tokuyama Glass. In addition, a cation exchanger is introduced into polystyrene, polybenzimidazole, polyphosphazene, and the like to form a cation by mixing a resin having excellent mechanical properties such as PEEK, polysulfone, polyimide, polyetherimidazole, and polyphenylene sulfide sulfone. It is used as a substrate for the exchange membrane.

Bulk polymerization, latex, and paste methods, which are polymer polymerization methods, are mainly used for the preparation of the cation exchange membrane. The bulk polymerization method is one of the most common methods of copolymerizing styrene and divinylbenzene. However, the monomers are brittle and have a disadvantage of using plasticizers. In addition, a special tool is required for manufacturing thin films using the same. Has a high disadvantage.

Therefore, the latex method is used as a method to solve the above disadvantages. The latex method is a method of preparing a membrane by oxidative crosslinking after depositing a latex of a rubbery styrene-butadiene copolymer on a support and drying it. Due to the hydrophobicity of the latex, the affinity with water is reduced, and the performance is deteriorated, and the physical properties caused by the remaining additives are deteriorated and the electrical properties are deteriorated.

In another method, a paste is prepared by mixing an additive such as a crosslinking agent with a polymer powder, and then impregnating it into a plastic cloth such as PVC, and then producing an ion exchange membrane by a functionalization method. The surface is rough and many additives for increasing the mechanical strength are required, which leads to a complicated manufacturing process and high manufacturing cost of the film.

Therefore, there is a need for a new method to remedy the disadvantages of conventional filmmaking.

In the present invention, to prepare an ion exchange resin using styrene resins and derivatives thereof and a solution using the same to prepare ion exchange membranes for electrolytic electrodes that are easy to dissolve and to introduce functional groups in order to improve the disadvantages of membrane production methods known to date. It is to provide a method for producing an ion exchange membrane by a coating method.

The method for producing an ion exchange resin according to the present invention provides a method which can be easily and easily prepared, and as a method for preparing the membrane, an ion exchange solution coating method is a paste forming step adopted in the conventional method for producing an ion exchange membrane, Without going through a polymerization step or the like, deposition and swelling processes are unnecessary, and additives for film production such as a crosslinking agent are not necessary.

In addition, polystyrene resins, as well as waste EPS, can be recycled as raw materials for the production of membranes, and since the commercialized polymers are directly dissolved in a solvent, the process is very simple and the reaction time such as functionalization is short. The unit price is very inexpensive.

On the other hand, the characteristics of the present invention is to dissolve ESP or polystyrene (hereinafter referred to as PS) to prepare a solution, and then to introduce functional groups, which can be cast directly using a device such as doctor blade on a stable and stable plastic support. Therefore, it is possible to produce a film having a uniform surface with a thickness suitable for the purpose.

In addition, by preparing and using an ion exchange coating solution, it is possible to manufacture membranes of various shapes and sizes, and the solution can be mixed with other materials to be molded into a slurry to be applied to the production of functional composite electrode materials. And it is easy to remove by repeatedly casting the bubbles in the membrane, which is a disadvantage of the existing ion exchange membrane, and functionalized evenly in the solution state when manufacturing the membrane, so that the functional groups are evenly distributed throughout the membrane, and the ion exchange performance is high, and the mechanical strength of PS is weak. By using a support of physical properties with excellent properties, it is possible to produce a film having excellent mechanical properties such as tensile strength.

Accordingly, the present invention provides an ion exchange resin for membrane production by dissolving related polymer materials such as EPS and PS in a solvent, and a method for manufacturing an ion exchange membrane for highly selective electrodes using the same.

The present invention for achieving the above object of the present invention relates to a method for producing a cation exchange membrane and an anion exchange membrane to provide a new method for producing an ion exchange membrane.

In the production of cation exchange membranes, PS resins such as EPS or PS, EPS wastes, etc. as raw materials for the ion exchange membranes are 5 to 30 w / v% based on solvents such as 1,2-dichloroethane (hereinafter referred to as DC) and chloroform. One or two or more of the polymers are selected and dissolved to prepare an ion exchange solution.

Subsequently, silver sulfate or acetyl sulfate was added in an amount of 0.005 to 0.01 mol% based on the PS-based resin as a sulfonation catalyst, followed by mixing to prepare a polymer solution. Then, sulfuric acid was added to a solvent in a polymer solution to prepare a cation exchange membrane. The reaction temperature is changed from room temperature to 80 ° C. and the sulfonation reaction is performed while stirring. In the present invention, when performing a partial crosslinking reaction simultaneously with the sulfonation reaction, chlorosulfonic acid may be additionally added, in which the ratio of chlorosulfonic acid / sulfuric acid is added dropwise to 1/10 to 1/100 by volume ratio. It provides a method for producing a sulfonated cation exchange solution by changing the reaction temperature from 0 ℃ to 50 ℃. In the case of adding chlorosulfonic acid to sulfuric acid, the addition of 1 to 10 vol% more preferably increases the function of the ion exchange solution and improves the durability of the membrane through partial crosslinking between benzene rings including cation exchange groups.

The reaction time is not limited because it can be controlled by appropriate control, for example, the process of preparing the ion exchange solution is preferably 40 minutes at 65 ℃ when using a sulfate sulfonating agent to improve the ion exchange performance In the case where chlorosulfonic acid is added, it is preferable that the chlorosulfonic acid is added within 30 minutes at 30 ° C.

On the other hand, in the step of preparing the membrane using the ion exchange resin prepared above, the uneven surface of the membrane by outgasing during casting of the ion exchange solution may bring a high membrane resistance and a decrease in ion transport rate, In order to prevent this, the cation exchange resin membrane prepared by the above method is put in an inert solvent, and sulfosalicylic acid, sulfoacetic acid, sulfosuccinic acid and the like are added to a polar solvent such as water or ethanol, which are inert solvents, to increase crosslinking and ion selectivity. By dipping into a solution of 0.1 ~ 10wt% relative to the membrane to prepare the membrane can reduce the closed pores of the surface and at the same time it is better to partially crosslink the surface by a second force (second force).

Next, a method for producing an anionic ion exchange resin will be described.

The preparation process of the aminated anion exchange solution is selected from chloromethyl methyl ether (hereinafter referred to as CMME) and chloromethyl ether (hereinafter referred to as CME) in a solution prepared in the same manner as the rate of dissolving EPS in the cation exchange solution preparation process. Add 1 or more to react. For example, chloromethyl methyl ether is added at a molar ratio of 1: 2 based on EPS, and the reaction temperature is maintained at 5 to 10 ° C. higher than the boiling point (bp) of CMME, and reacted for 3 to 6 hours to prepare a methyl chloride PS solution. do. At this time, as a Lewis acid, a catalyst such as zinc chloride, aluminum chloride, iron tetrachloride or the like is added at 0.1 to 3 wt% based on the PS resin to react.

In order to prepare an aminated anion exchange solution, a tertiary amination agent such as trimethylamine, dimethylamine, and triethylamine was added at 5 to 30 vol% based on the PS, and then the reaction temperature was changed from room temperature to 80 ° C. A quaternary amination reaction is carried out while changing and stirring to prepare an anion exchange solution. At this time, to promote quaternary ammonium, 0.02 to 0.05 mol of sodium iodide is added as a catalyst component based on 100 ml of trialkylamine as an amine agent, and the reaction temperature is changed from room temperature to 80 ° C, preferably 60 to 80 ° C, while stirring. The amination reaction is performed for 1 to 6 hours to prepare an anion exchange solution through a quaternary amination reaction.

Methanol is added to the amount and anion exchange solution prepared by the above method to stop the reaction, and at the same time, it is left to separate the layers to remove the unreacted material to prepare an ion exchange resin.

Hereinafter, an ion exchange membrane using the ion exchange resin will be described.

The ion exchange membrane provides a method for preparing an ion exchange membrane by casting a sulfonated or aminated ion exchange solution prepared by the above method onto a plastic substrate using an apparatus such as a doctor blade and then drying.

Membranes prepared by the above method are prepared by washing sufficiently with 10-40% aqueous sulfuric acid solution and then again with distilled water. Thereafter, it is dried, for example, dried at room temperature for 0.5 to 1 hour, and prepared.

Hereinafter, the present invention will be described in detail according to each process.

The present invention relates to a method for producing an ion exchange membrane recycled PS or EPS, and can be divided into a process for dissolving PS or EPS, sulfonation, chloride chloride, amination, and ion exchange membranes using these solutions. .

(One) EPS Dissolution process

PS resin is dissolved by stirring in DC or chloroform 10-30 vol% to prepare a PS polymer solution.

At this time, the dissolution temperature is preferably maintained at 30 to 40 ℃ and the dissolution time is carried out between 1 to 4 hours.

(2) Sulfonation process

In the cation exchange resin preparation solution, silver sulfate or acetyl sulfate, which is a sulfonation catalyst, is contained in an amount of 0.005 to 0.01 mole ratio of PS to PS in a polymer solution having 80 to 90% by weight of solvent compared to PS polymer. Adding. Sulfuric acid, which is a sulfonating agent, is added at 5 to 30 vol% with respect to the solvent, and then the sulfonation reaction is performed by stirring for 10 to 60 minutes at a reaction temperature of 25 ° C to 80 ° C, preferably 60 to 70 ° C under a nitrogen atmosphere. Or when using a mixture of chlorosulfonic acid / sulfuric acid as a sulfonating agent, the ratio of chlorosulfonic acid / sulfuric acid is adjusted dropwise to 1/10 to 1/100 dropwise, and the reaction temperature is changed to 0 ℃ to 50 ℃ to sulfonated cation exchange Prepare a solution.

(3) methylation process

To the same EPS solution, chloromethyl methyl ether (hereinafter referred to as CMME) or chloromethyl ether (hereinafter referred to as CME) is added at a molar ratio of 1: 1.3 to 3, preferably 1: 2, based on EPS, and the reaction temperature is CMME. Or 5 to 10 ° C. higher than the boiling point (bp) of CME, and reacted with stirring for 3 hours under nitrogen atmosphere, preferably with stirring for 3 hours, to methylate chloride. At this time, as a Lewis acid, a catalyst such as zinc chloride, aluminum chloride, iron tetrachloride or the like is added at 0.1 to 3 wt% with respect to the resin component and reacted. In addition, in order to increase the yield of the reaction should be used after sufficiently removing the water in the chloride catalyst. In this process, the benzene ring can be halomethylated to introduce amine groups.

(4) Amination Process

The tertiary amine, such as trimethylamine, was added to the methyl chlorided PS solution at 5-30 vol% based on the PS solution, and then 0.02-0.05 mol of sodium iodide was added based on 100 ml of trimethylamine as an amination agent, and the reaction temperature was raised from room temperature to 80%. Preferably an anion exchange solution is prepared through a quaternary amination reaction by changing the temperature from 60 ° C. to 80 ° C. and stirring for 1 to 6 hours while stirring.

(5) Ion exchange membrane manufacturing process

The functionalized positive and negative ion exchange resin solution is surface treated to form an ion exchange membrane having a thickness of 100 μm or less using a doctor blade on a mesh network such as hydrophilized polyester or PVC and dried at room temperature to prepare a membrane. . In this case, the thickness of the membrane can be controlled by repeatedly coating the ion exchange solution several times. It is preferable to continuously supply a small amount of ion exchange solution in an enclosed space in order to prevent a sudden increase in viscosity according to the volatilization of the initial solvent such as DC and chloroform during the preparation of the membrane. On the other hand PE by using the fluidity of the liquid through the viscosity control of the ion exchange solution. It is a technology characterized in that it can be manufactured by any method of casting, coating, laminating on a support such as PVC film or pipe form.

However, in the case of cation exchange resins, the membrane has a high resistance to membranes and a low ion transport rate due to the uneven surface of the membrane during casting of the ion exchange solution. At the same time, by adding sulfosalicylic acid, sulfoacetic acid, sulfosuccinic acid, etc. to increase ion selectivity, it is possible to reduce the closed pores of the surface and to partially crosslink the surface by secondary force. good.

In the case of the anion exchange membrane, to completely remove the unreacted tertiary amine, etc., washing with 0.05 to 1 N ammonium salt and then sufficiently washing with water can further increase ion selectivity and remove impurities on the surface.

By using the ion exchange membrane manufacturing method according to the present invention can be used in the electrodialysis process of excellent performance in a very low cost and simple process because it can replace the expensive ion exchange membrane used in the current electrodialysis device is cheap and processing cost It can be widely commercialized in the field of softening device and industry, separation of useful metals in mine wastewater and recovery of heavy metals in other industrial wastewater. The application of the ion exchange solution to the desired substrate is free of molding and the ability to introduce the desired functional group is expected to have a variety of applications.

The ion exchange membrane produced by the present invention can also be expected to recycle effect by using waste EPS resin as a raw material, it can be seen in the future global membrane market due to such a price competitiveness and high performance of the membrane.

The present invention relates to the production of a high performance ion exchange membrane for a CDI electrolytic electrode, and the present invention will be described in more detail with reference to the following examples.

One. Sulfonation  Preparation of Cation Exchange Membrane

As shown in Table 1 below, the ion exchange solution prepared by dissolving EPS in chloroform was changed to a concentration of chlorosulfonic acid / sulfuric acid sulfonating agent to sulfonate to prepare a cation exchange membrane.

Example 1 Preparation of Cation Exchange Membrane

After dissolving 15 g of EPS in 100 ml of DC, 0.02 g of silver sulfate was added and sulfuric acid was added at a concentration of 10v / v% of the solvent during the sulfonation process. ), 30 (b), 45 (c), 60 (d) was reacted to prepare a cation exchange solution.

1 is an infrared spectroscopic analysis result of a cation exchange membrane according to an embodiment of the present invention. 1, the characteristics of a sulfonic acid group that is the infrared spectroscopy of a cation-exchange membrane produced results appear in the slash-and-burn sulfone peak 1028cm ^-1, 1100 ~ 1200cm ^- was confirmed that the sulfonation from those appearing in the ^first cation exchange membrane prepared .

The prepared and functionalized solution was added dropwise with methanol to 2 to 3 ml to stop the reaction, and at the same time to stop the reaction to separate and remove the unreacted sulfuric acid and silver by layer separation, and the casting was a polyester film having a thickness of 70 μm. A cationic membrane was prepared by casting a film) (100mesh), and the prepared cation exchange membranes were washed in 40% 20% 10% sulfosalicylic acid aqueous solution, sufficiently washed in distilled water, and dried at room temperature for 1 hour.

Example 2 Preparation of Cationic Resin Membrane

The cation exchange membrane was prepared in the same manner as in Example 1 by adding a sulfonating agent at a molar ratio of 10/1 in a volume ratio of 10 (a) and 20vol% (b) to a solvent in a molar ratio of 10/1. Except that, it was prepared in the same manner as in Example 1.

Comparative Example 1 : When no crosslinking agent was added during film formation

The same experiment was conducted except that the membrane was prepared in comparison with Example 1 and not treated with sulfosalicylic acid as a crosslinking agent. The results are shown in Table 1.

2. Amination Anion exchange membrane

Example 3 Preparation of Anion Exchange Membrane

Dissolve 15 g of EPS in 100 ml of DC solvent, add 5.5 g of CMME, and add ZnCl ₂ as a catalyst. Add 0.05 g The reaction was carried out at 30 ° C. for 3 hours. The chloromethylated solution was prepared by adding trimethylamine, an aminizing agent, at 20, 30 vol% compared to PS, and changing the reaction time at 2, 4 hours to prepare an anion exchange solution. At the same time casting on a polyester film (100mesh) and repeated washing in 0.1N ammonium chloride and then washed in distilled water and dried at room temperature for 1 hour. Infrared spectroscopic analysis of the prepared anion exchange membrane confirmed that the aminated cation exchange membrane was prepared from the characteristic peak of the amine group at 3500 cm ^-1 .

3. Characterization of membrane

(1) Measurement of ion exchange capacity

In order to measure the ion exchange capacity, the ion exchange capacity was determined by an acid salt titration using 1N NaOH aqueous solution and 1N HCl aqueous solution by the following equation. In the case of the anion exchange membrane, the order of NaOH and HCl was changed.

IEC (meq / g) = {(V _HCl × N _HCl ) -5 (V _NaOH × N _NaOH )} / Weight of sample (g)

IEC: ion exchange capacity (meq / g)

V _HCl : volume of HCl (ml), V _NaOH : volume of NaOH (ml)

N _HCl : Concentration of HCl (N), N _NaOH : Concentration of NaOH (N)

(2) moisture content measurement

The ion exchange membrane was cut to a size (3 × 3 cm) and then immersed in 0.1 M NaCl solution to swell sufficiently, and then free water on the surface of the ion exchange membrane was removed and weighed, and dried in a vacuum oven at 60 ° C. for 24 hours. After cooling, the water content was determined by weight.

WC (%) = {(W _wet -W _dry ) / W _dry } x 100

WC: Water content (%), W _wet : Weight after tacking (g), W _dry : Weight after drying (g)

(3) Ion transport number : In order to measure the ion transport water of the ion exchange membrane, the membrane cut to a certain size (3 × 3 cm) was immersed in 0.1 M NaCl solution to reach an equilibrium state, and then 2-compartment cell was obtained. After assembling and filling 0.01 M NaCl on the right side and 0.1 M NaCl on the left side, the Ag / AgCl reference electrode was connected to a multi meter to measure the potential difference.

(4) membrane resistance

A 2-compartment cell was used to measure the electrical resistance of the ion exchange membrane. Cut the membrane to a certain size (3 × 3 cm) and insert it into the electrochemical cell, measure the electrical resistance in 0.1 M NaCl solution (R ₁ ), remove the membrane and measure the resistance of the electrolyte solution only (R ₂ ) The value ER was obtained.

ER (Ωm ² ) = (R ₁ -R ₂ ) · A

R: Resistance (Ω), A: Area (m ² )

Table 1 Performance of Example 1

    Example Sulfonation reaction time (min)  Water content (%)  Ion exchange capacity (meq / g) Membrane Resistance (ohm-cm ² ) Ion transport water (-) Example 1a 15 17.8 1.6 13 0.86 Example 1b 30 20.7 2.0 9 0.88 Example 1c 45 23.1 2.2 8 0.92 Example 1d 60 28.5 2.3 8 0.92 Comparative Example 1a 15 15.3 1.5 14 0.79 Comparative Example 1b 30 18.7 1.9 13 0.81 Comparative Example 1c 45 20.8 2.0 14 0.83 Comparative Example 1d 60 25.7 2.2 13 0.86

As shown in Table 1 above, when the reaction time was changed at a constant concentration of the sulfonating agent from Examples 1 (a) to 1 (d), the basic characteristics of the membrane were changed according to the reaction time. The increase in water content and ion exchange capacity and the electrical properties of the membrane show that it is advantageous as an ion exchange membrane due to a decrease in membrane resistance and an increase in ion transport. However, it can be seen that the overall film performance is reduced when the film is formed and not treated with a crosslinking agent.

Table 2 Film Performance of Example 2

Example Catalyst (v / v%)    Water content (%)  Ion exchange capacity (meq / g) Membrane Resistance (ohm-cm ² ) Ion transport water (-) a 10 24.76 2.5 7 0.98 b 20 27.54 2.7 7 0.97

In Table 2, the increase in the concentration of the sulfonating agent resulted in a decrease in the relative membrane resistance and an increase in the ion transport. This is because the membrane performance was improved due to the addition of chlorosulfonic acid. In other words, the ion transport degree was> 0.97, showing sufficient potential as a commercialized membrane. Increasing the content of chlorosulfonic acid increased the partial crosslinking, resulting in a decrease in the relative film resistance.

Table 3 Membrane Performance of Example 3

 Example  Trimethylamine         Response time (hours) Water content (%)  Ion exchange capacity (meq / g) Membrane Resistance (ohm-cm ² ) Ion transport water (-) a 20 2 17.80 0.8 14 0.91 b 30 2 20.76 1.1 11 0.93 c 20 4 23.10 1.2 8 0.97 d 30 4 24.05 1.3 7 0.97

As shown in the Example of Table 3, as the amount of trimethylamine was increased, the water content increased, the ion exchange capacity was 0.8 ~ 1.3 meq / g, the membrane resistance was reduced to 14 ~ 7, and the ion transport was increased to 0.91 ~ 0.97 It was.

The present invention described above is not limited to the above-described embodiment and the accompanying drawings, and various substitutions, modifications, and changes are possible within the scope without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

1 is an infrared spectroscopy analysis of the cation exchange membrane according to an embodiment of the present invention.

Claims (9)

Preparing an ion exchange resin solution; Coating the ion exchange resin solution on a substrate of a mesh; Post-treating the coated ion exchange resin membrane; Drying; A method for producing an ion exchange resin membrane for CDI electrodes. The method of claim 1, The ion exchange resin is a method for producing an ion exchange resin membrane for a CDI electrode, characterized in that to give a cation exchange group to a polystyrene resin using a mixed acid of sulfuric acid or chlorosulfonic acid / sulfuric acid. 3. The method of claim 2, The reaction for imparting a cation exchange group is a method for producing an ion exchange resin membrane for a CDI electrode, characterized in that the production using silver sulfate or acetyl sulfate as a catalyst. The method of claim 3, The post-treatment of the ion exchange membrane is a CDI, characterized in that it is immersed in a solution containing at least one component selected from 0.1 ~ 10wt% of sulfosalicylic acid, sulfo acetic acid, sulfosuccinic acid with respect to the inert solvent of the ion exchange membrane and then washed with water. Method for producing an ion exchange resin membrane for electrodes. The method of claim 4, wherein The mixed acid of sulfuric acid or chlorosulfonic acid / sulfuric acid is 1/10 ~ 1/100 molar ratio of 5 ~ 30v / v% with respect to the solvent, the styrene resin is produced at 5 ~ 30w / v% with respect to the solvent Method for producing an ion exchange resin membrane for electrodes. The method of claim 1, In the step of preparing the ion exchange resin solution, chloromethylmethyl ether or chloromethyl ether is added to the polyester resin solution at a ratio of 1: 1.3 to 3 mol based on the resin, and Lewis acid as a catalyst is 0.1 to 3 wt% based on the resin component. A method for producing an ion-exchange resin membrane for a CDI electrode, which is prepared by adding%, followed by an amination reaction, followed by quaternary ammoniumation. The method of claim 6, Said Lewis acid is zinc chloride, aluminium chloride or iron chloride method of producing an ion exchange resin membrane for a CDI electrode. The method of claim 7, wherein The quaternary ammonium reaction is reacted with trialkylamine, and the ion exchange resin for CDI electrode is prepared at 20 to 80 ° C. by adding 0.02 to 0.05 mol of sodium iodide based on 100 ml of the trialkylamine as a catalyst. Method of preparing the membrane. The method of claim 8, The Lewis acid is 0.1 ~ 3wt% with respect to the resin, trialkylamine is 5 ~ 30v / v% with respect to the resin solution, the resin is prepared by dissolving at 5 ~ 30w / v% with respect to the solvent Ion exchange resin membrane.

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