JP2011183298A - Method for recycling silane coupling agent-containing solution and method for producing silane coupling agent by using the method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method by which a silane coupling agent is separated from a silane coupling agent-containing solution without using considerable energy and without generating waste materials, and then the separated silane coupling agent is recovered and recycled and a solvent from which the silane coupling agent is removed, is recovered. <P>SOLUTION: A method for recycling the silane coupling agent-containing solution includes an adsorption step of bringing the silane coupling agent-containing solution into contact with an ion exchanger to adsorb the silane coupling agent on the ion exchanger. A method for producing the silane coupling agent includes the method for recycling the silane coupling agent-containing solution. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a solution recycling method including a silane coupling agent and a method for producing a silane coupling agent using the solution recycling method.

  In recent years, home appliances such as liquid crystal televisions using liquid crystal panels, personal computers, mobile terminals, and other products have rapidly spread due to the features such as thinness, light weight, and low power consumption. Furthermore, the screens of products that use liquid crystal panels The size is also increasing. As a result, the production volume of liquid crystal panels is rapidly increasing.

  With the increase in production of liquid crystal panels, the amount of parts and materials used for manufacturing is increasing, and the amount of emissions discharged from the manufacturing process is also increasing rapidly. These discharged substances are not only in the form of glass substrates and optical films, solid substances but also in the amount of waste liquid.

  A silane coupling agent has a functional group that binds to an inorganic substance and a functional group that binds to an organic substance, and is widely used as a material that acts as a bridge between an inorganic material and an organic material. Such silane coupling agents are used in filler-filled inorganic-organic composite materials, adhesives, elastomers, paints, silane cross-linked resins, etc., and interface modification of FRP (glass fiber reinforced plastic) glass fibers and plastic interfaces. Also used as an agent. In the manufacturing process of liquid crystal panels, silane coupling agents are used to improve the adhesion between organic and inorganic materials, and the amount of silane coupling agents used and the amount of silane coupling agents increase with the increase in liquid crystal panel production. The amount of effluents containing is also increasing.

  For example, Japanese Patent Application Laid-Open No. 8-150389 (Patent Document 1) discloses a method of removing a silane coupling agent from a waste liquid discharged in a production process of a silane coupling agent and recovering a useful chemical solution. . In the method described in Patent Document 1, an ethylenediamine hydrochloride solution containing a silane coupling agent is brought into contact with activated carbon, the silane coupling agent is adsorbed and removed, and an ethylenediamine aqueous solution is recovered. In the method described in Patent Document 1, the activated carbon adsorbed by the silane coupling agent is incinerated, or the silane coupling is desorbed and recovered from the activated carbon with an organic solvent.

JP-A-8-150389

  While the formation of a recycling-oriented society is demanded, the waste discharged from the liquid crystal panel manufacturing process, which is increasing, is also required to be effectively used again as a resource. With regard to waste liquids containing silane coupling agents discharged from the manufacturing process of liquid crystal panels whose production volume has been increasing rapidly in recent years, from the viewpoint of effectively using resources, the silane coupling agent is separated and the solvent of the waste liquid is recovered. However, it is desired to use it again in the liquid crystal panel manufacturing process.

  Currently, a shortage of water resources is progressing globally due to population growth and economic development, and it is hoped that water resources used in the manufacturing process of industrial products will be effectively reused as resources after use. . For this reason, when the solvent of the silane coupling agent in the waste liquid is water (preferably pure water), it is considered to be particularly useful to reuse it.

  However, the waste liquid containing the silane coupling agent discharged from the manufacturing process of electrical and electronic equipment such as liquid crystal panels is incinerated as industrial waste, and no technology for recycling is disclosed.

  Even in the method described in Patent Document 1 described above, when activated carbon is incinerated, there is a problem that carbon dioxide is generated during incineration as well as an increase in industrial waste. In addition, when the silane coupling agent is desorbed and recovered using an organic solvent, a waste liquid containing the organic solvent is generated, and a large amount of energy is used for the treatment. .

  The present invention has been made to solve the above-described problems, and the object of the present invention is to use a solution containing a silane coupling agent without using a great deal of energy and without generating waste. It is intended to provide a method for recovering a solvent (preferably pure water) from which a silane coupling agent has been removed while separating, recovering and recycling the silane coupling agent.

  The present invention is a method for recycling a solution containing a silane coupling agent, and includes an adsorption step in which a solution containing a silane coupling agent is brought into contact with an ion exchanger and the silane coupling agent is adsorbed on the ion exchanger. It is characterized by that.

  The ion exchanger used in the present invention preferably contains an ion exchanger having at least one of carboxylic acid and sulfonic acid as an exchange group.

  The recycling method of the present invention comprises a desorption regeneration step in which an ion exchanger adsorbed with a silane coupling agent is brought into contact with a strongly acidic solution to desorb the silane coupling agent from the ion exchanger and regenerate the ion exchanger. It is preferable to include (hereinafter, this case is referred to as “recycling method A”).

  The recycling method of the present invention may also include a desorption step of bringing the ion exchanger adsorbed with the silane coupling agent into contact with a strongly basic solution and desorbing the silane coupling agent from the ion exchanger ( Hereinafter, this case is referred to as “recycling method B”.) In the recycling method B, it is preferable to further include a regeneration step in which the ion exchanger after desorption of the silane coupling agent is brought into contact with a strongly acidic solution to regenerate the ion exchanger.

  The recycling method A of the present invention uses an electrodialyzer to separate and recover a silane coupling agent from a mixed solution of a silane coupling agent and a strongly acidic solution obtained in the desorption regeneration step. It is preferable to further include a coupling agent recovery step. In this case, using an electrodialysis apparatus in which the anode and cathode are separated into an anode tank and one or more intermediate tanks and a cathode tank by using a plurality of diaphragms, water is supplied to the anode tank and the intermediate tank, and the desorption is performed on the cathode tank. It is preferable to supply the mixed solution obtained in the regeneration step.

  Further, in the recycling method B of the present invention, using an electrodialysis apparatus, the silane coupling agent is separated from the mixed solution of the silane coupling agent and the strongly basic solution obtained in the desorption step, and recovered. It is preferable to further include a silane coupling agent recovery step. In this case, it is preferable to use an electrodialysis apparatus in which the anode and the cathode are separated by a diaphragm and supply the mixed solution obtained in the desorption process to the anode side.

  In the recycling method B of the present invention, the strongly basic solution and the strongly acidic solution are separated from the mixed solution of the strongly basic solution and the strongly acidic solution obtained in the regeneration step using an electrodialyzer. It is preferable to further include an acid / base recovery step for recovery. In this case, using an electrodialysis apparatus in which the anode and the cathode are separated into an anode tank and one or more intermediate tanks and a cathode tank with a plurality of diaphragms, water is supplied to the anode tank and the cathode tank, It is preferable to supply the mixed solution obtained in the regeneration step.

  The silane coupling agent in the recycling method of the present invention is preferably an amino silane coupling agent.

  The present invention further provides a method for producing a silane coupling agent, including the above-described method for recycling a solution containing the silane coupling agent of the present invention.

  According to the present invention, a solvent (preferably pure water) can be efficiently recovered from a solution containing a silane coupling agent without consuming a great deal of energy and without generating waste. Provided are a method for recycling a solution containing a silane coupling agent that can recover the silane coupling agent and that does not generate waste, and a method for producing a silane coupling agent using the method.

It is a flowchart which shows typically a preferable example of the recycling method A of this invention. It is a figure which shows typically an example of the electrodialysis at the time of using hydrochloric acid as a strongly acidic solution in the desorption process of the recycling method A of this invention. It is a flowchart which shows typically a preferable example of the recycling method B of this invention. It is a figure which shows typically an example of the electrodialysis in a silane coupling agent collection | recovery process at the time of using sodium hydroxide as a strong base in the desorption process of the recycling method B of this invention. It is a figure which shows typically an example of the electrodialysis in the acid and base recovery process at the time of using sodium hydroxide as a strong base in the desorption process of the recycling method B of this invention. It is a graph which shows the adsorption | suction behavior of the silane coupling agent to a cation exchange resin.

  The method for recycling a solution containing a silane coupling agent according to the present invention includes an adsorption step in which a solution containing a silane coupling agent is brought into contact with an ion exchanger and the silane coupling agent is adsorbed on the ion exchanger. And According to such a recycling method of the present invention, a solvent (preferably pure water) is efficiently produced from a solution containing a silane coupling agent without consuming a great deal of energy and without generating waste. As a result, the silane coupling agent can be efficiently recovered and waste is not generated.

  The liquid crystal panel has a structure in which an inorganic material and an organic material are combined in a complicated manner, and a silane coupling agent that bridges the inorganic material and the organic material is used in the manufacturing process. Due to the adaptability to the manufacturing process, the amount of waste liquid containing a silane coupling agent (hereinafter simply referred to as “waste liquid”) has increased with the increase in production of liquid crystal panels. It is required to recover the water resources as well as the agent. The method for recycling a solution containing the silane coupling agent of the present invention can be suitably applied to the waste liquid discharged in the liquid crystal panel manufacturing process. The method for recycling a solution containing a silane coupling agent of the present invention is also suitably applied to waste liquid discharged in a semiconductor manufacturing process, a paint manufacturing process, an FRP manufacturing process, etc. in addition to a liquid crystal panel manufacturing process. be able to.

  The silane coupling agent has a structure represented by the following general formula (I).

As shown in the above general formula (I), the silane coupling agent has a hydrolyzable group OR and an organic functional group Y, and the hydrolyzable group has reactivity with inorganic materials such as glass fiber, filler, and metal. The organic functional groups are highly reactive with organic materials such as thermoplastic resins, thermosetting resins, and elastomers. In general formula (I), R represents an alkoxy group such as methyl or ethyl, an acetoxy group, or the like. This hydrolyzable group is hydrolyzed by moisture in the aqueous solution, moisture in the air, etc., and a highly reactive silanol group (Si—OH group) is generated. In addition, the organic functional group represented by Y in the figure is an amino group (—NH ₂ ), a vinyl group (H ₂ C═CH—), or the like.

  The silane coupling agent in the present invention is preferably an amino silane coupling agent represented by the following formula because it is charged in an aqueous solution and can be easily separated by an ion exchanger using its properties.

Specifically, amino-based silane coupling agents include 3-aminopropyltrimethoxysilane (H ₂ NC ₃ H ₆ Si (OCH ₃ ) ₃ ), 3-aminopropyltriethoxysilane (H ₂ NC ₃ H ₆ Si). (OC ₂ H ₅ ) ₃ ), 3- (2-aminoethyl) aminopropyltrimethoxysilane (H ₂ NC ₂ H ₄ NHC ₃ H ₆ Si (OCH ₃ ) ₃ ).

  Examples of the ion exchanger used in the adsorption step in the present invention include bead-shaped ion exchange resins and fibrous ion-exchange fibers. Charged silane coupling agent can be easily adsorbed, and the silane coupling agent can be desorbed from the ion exchanger by using an acidic or basic solution. Therefore, it is preferable to use an ion exchanger having at least one of carboxylic acid and sulfonic acid as an exchange group. Examples of such ion exchangers include weakly acidic cation exchange resins having carboxylic acid groups as exchange groups, strongly acidic cation exchange resins having sulfonic acid groups as exchange groups, and sulfonic acid groups as exchange groups. A strong acid cation exchange fiber is mentioned. Examples of weakly acidic cation exchange resins having a carboxylic acid group include Diaion WK10 (manufactured by Mitsubishi Chemical Corporation), Diaion WK11 (manufactured by Mitsubishi Chemical Corporation), and Amberlite IRC76 (manufactured by Rohm and Haas). ) Etc. can be used. Examples of strongly acidic cation exchange resins having a sulfonic acid group include Diaion SK1B (Mitsubishi Chemical Corporation), Diaion SK110 (Mitsubishi Chemical Corporation), Amberlite IR120B (Rohm and Haas). Commercially available products such as those manufactured by the company) can be used. Commercially available products such as IEF-SC (manufactured by Nichibi Corporation) can be used as the strong acid cation exchange fiber having a sulfonic acid group. Above all, the silane coupling agent can be easily desorbed and recovered from the resin with a strong acidic solution, and can be regenerated into H form. It is more preferable to use Hereinafter, the example using the weakly acidic cation exchange resin which has a carboxylic acid group as an ion exchanger is demonstrated concretely. The ion exchanger is not limited to the following examples, and a strongly acidic cation exchange resin having a sulfonic acid group as an exchange group or a strongly acidic cation exchange fiber having a sulfonic acid group as an exchange group may be used. it can.

  As a method of contacting the solution containing the silane coupling agent and the cation exchange resin in the adsorption step, for example, there is a method of filling the column with the cation exchange resin and passing the solution through the column. At this time, the liquid flow rate is preferably 1 to 50 / h in space velocity.

  In the silane coupling agent, for example, as shown below, a hydrogen ion is coordinated to an amino group in a solution and has a positive charge and exhibits a cation property.

  Therefore, when the silane coupling agent is brought into contact with the cation exchange resin, it attracts the exchange group of the cation exchange resin having a negative charge, and the silane coupling agent is adsorbed on the cation exchange resin as follows. Adsorption of the silane coupling agent onto the cation exchange resin is in the form of a salt, and the acidity of the carboxylic acid group is weak. Thus, the silane coupling agent is adsorbed to the cation exchange resin with a structure that can be easily desorbed and recovered as described later.

  The silane coupling agent is removed from the solution (waste liquid) containing the silane coupling agent after contacting with the cation exchange resin, and the solvent (preferably pure water) can be recovered. The recovered solvent (preferably pure water) can be used in the manufacturing process of the liquid crystal panel. Further, it can be widely used for industrial applications such as semiconductor manufacturing and electronic circuit board manufacturing.

  The amount of the silane coupling agent that can be removed from the waste liquid by contact with the cation exchange resin is usually 100 g or more with respect to 1 L of the cation exchange resin. For example, if the concentration of the silane coupling agent in the waste liquid is 1%, if the volume of the cation exchange resin is 1 L, the silane coupling agent can be removed from 10 L or more of the waste liquid. Further, if the concentration of the silane coupling agent in the waste liquid is 0.1%, the silane coupling agent can be removed from 100 L or more of the waste liquid if the volume of the cation exchange resin is 1 L.

  The solution recycling method including the silane coupling agent of the present invention includes the first method (recycling method A) including the adsorption step and desorption regeneration step described above, and the adsorption step, desorption step, and regeneration described above. And a second method (recycling method B) including processes. Hereinafter, the recycling methods A and B will be described in detail separately.

  FIG. 1 is a flowchart schematically showing a preferred example of the recycling method A of the present invention. In the recycling method A of the present invention shown in FIG. 1, first, in the adsorption step (step A-1) described above, the solution containing the silane coupling agent is brought into contact with the ion exchanger, and the silane coupling agent is used. A solvent (pure water) from which the silane coupling agent has been removed by adsorption onto the ion exchanger is recovered.

In the recycling method A, in the subsequent desorption regeneration step (step A-2), the ion exchanger adsorbed with the silane coupling agent is brought into contact with a strongly acidic solution to desorb the silane coupling agent from the ion exchanger. The ion exchanger is regenerated to H form. As the strong acid, for example, hydrochloric acid or the like can be used. When a weakly acidic cation exchange resin having a carboxylic acid group is used as the ion exchanger, the silane coupling agent and the cation exchange resin are bonded so as to form a salt as described above. For example, when the cation coupling resin adsorbed to the silane coupling agent is brought into contact with hydrochloric acid, the silane coupling agent and H ⁺ ions are substituted as shown below, and the silane coupling agent is desorbed from the cation exchange resin. . Thereby, the silane coupling agent can be concentrated and recovered. There is also hydrochloric acid that is not adsorbed by the cation exchange resin and is recovered as it is.

  The concentration of the strongly acidic solution used in the desorption recovery step is preferably within a range of 0.01 to 5.0N, and more preferably within a range of 0.1 to 1.0N. When the concentration of the strongly acidic solution is less than 0.01 N, the amount of the strongly basic solution necessary for desorption increases. When the concentration of the strongly acidic solution is greater than 5.0N, the cation exchange resin is greatly deteriorated. The amount of the strongly acidic solution is preferably 1 to 5 times the volume of the cation exchange resin. In this way, the silane coupling agent is concentrated, and a mixed solution of the silane coupling agent and the strongly acidic solution is recovered.

  The amount of the strongly acidic solution used for desorption regeneration of the silane coupling agent from the cation exchange resin is less than the amount of waste liquid that can be processed by one ion exchange treatment, and efficient recovery of pure water and resin regeneration And the silane coupling agent can be recovered and concentrated.

  By the desorption regeneration process, the cation exchange resin becomes H-form, and the silane coupling agent can be adsorbed again in the operation of the adsorption process.

  As shown in the example shown in FIG. 1, the recycling method A of the present invention preferably further includes a silane coupling agent recovery step (step A-3) after the desorption step (step A-2). In the silane coupling agent recovery step in the recycling method A, the silane coupling agent is recovered from the mixed solution of the silane coupling agent and the strong acid solution obtained in the desorption regeneration step using an electrodialysis apparatus.

  As a specific method of electrodialysis in the recycling method A, an electrodialysis apparatus in which a gap between an anode and a cathode is separated into an anode tank, a plurality of intermediate tanks, and a cathode tank with a plurality of diaphragms is used. It is preferable to supply water to the tank and supply the mixed solution obtained in the desorption / regeneration process to the cathode tank. Here, FIG. 2 is a diagram schematically showing an example of electrodialysis when hydrochloric acid is used as a strong acid in the desorption regeneration step of the recycling method A of the present invention. FIG. 2 shows an example in which an electrodialysis apparatus including an electrolytic cell 1 including an anode 2 and a cathode 3 and separated into three tanks by diaphragms 4 and 5 is shown. Of the three tanks partitioned by the diaphragms 4 and 5, the side with the anode 2 is called the anode tank 6, the side with the cathode 3 is called the cathode tank 7, and the tank between the anode tank 6 and the cathode tank 7 is called the intermediate tank 8. I will decide.

  Water is supplied to the intermediate tank 8 and the anode tank 6, and a mixed solution of a silane coupling agent and hydrochloric acid is supplied to the cathode tank 7. As the diaphragm, a cation exchange membrane can be suitably used as the diaphragm 4 between the anode tank 6 and the intermediate tank 8. As the diaphragm 5 between the cathode cell 7 and the intermediate cell 8, an anion exchange membrane is preferably used, and a membrane filter, a UF membrane, an unglazed plate, and the like can also be suitably used.

In the mixed solution of the silane coupling agent and strong acid solution obtained in the desorption regeneration step, for example, when the strong acid is hydrochloric acid, the silane coupling agent, Cl ⁻ ion, H ⁺ ion, and OH ⁻ ion are present. Exists. H ⁺ ions and OH ⁻ ions are present in the intermediate tank and the anode tank. When a voltage is applied between the anode 2 and the cathode 3, the silane coupling agent and H ⁺ ions in the mixed solution in the cathode chamber 7 are attracted toward the cathode, and the reaction of 2H ⁺ + 2e ⁻ → H ₂ occurs at the cathode 3. , Hydrogen is generated. The silane coupling agent stays in the cathode chamber 7. As a result, the silane coupling agent is recovered in the cathode chamber 7. The recovered silane coupling agent can be reused in, for example, a liquid crystal panel manufacturing process or a semiconductor manufacturing process.

Cl ⁻ ions and OH ⁻ ions in the mixed solution in the cathode chamber 7 are attracted to the anode 2 side, and move to the intermediate chamber 8 when an anion exchange membrane is used as the diaphragm 5. When a cation exchange membrane is used as the diaphragm 4 between the intermediate tank 8 and the anode tank 6, Cl ⁻ ions and OH ⁻ ions can move from the intermediate tank 8 to the anode tank 6 through the diaphragm 4. It cannot be performed and stays in the intermediate tank 8.

H ⁺ ions in the anode tank 6 are attracted to the cathode 3 side, and when a cation exchange membrane is used as the diaphragm 4, they pass through this and move to the intermediate tank 8. Further, although it is attracted to the cathode 3 side, when an anion exchange membrane is used as the diaphragm 5 between the intermediate cell 8 and the cathode cell 7, H ⁺ ions cannot pass through it and remain in the intermediate cell 8. Thus, hydrochloric acid is recovered in the intermediate tank 8. The recovered hydrochloric acid can be used again in the above-described desorption regeneration process.

On the other hand, in the anode 2, oxygen is generated by the reaction of 4OH ⁻ → O ₂ + 2H ₂ O + 4e ⁻ . Water can be recovered in the anode tank 6.

  FIG. 3 is a flowchart schematically showing a preferred example of the recycling method B of the present invention. In the recycling method B of the example of the present invention shown in FIG. 3, first, in the adsorption step (step B-1), the solution containing the silane coupling agent is brought into contact with the ion exchanger, and the silane coupling agent is ion-exchanged. The solvent (pure water) that is adsorbed on the body and from which the silane coupling agent has been removed is recovered. This adsorption process is the same as the adsorption process (step A-1) in the recycling method A, and the details are as described above.

In the recycling method B, in the subsequent desorption step (step B-2), the ion exchanger on which the silane coupling agent is adsorbed is brought into contact with a strongly basic solution, and the silane coupling agent is desorbed from the ion exchanger. As a strong base, sodium hydroxide, potassium hydroxide, etc. can be used, for example. When a weakly acidic cation exchange resin having a carboxylic acid group is used as the ion exchanger, the silane coupling agent and the cation exchange resin are bonded so as to form a salt as described above. When, for example, a sodium hydroxide solution is brought into contact with the cation exchange resin on which the silane coupling agent is adsorbed as a strongly basic solution, the silane coupling agent and Na ⁺ ions are substituted as shown below, and the silane coupling agent Desorbs from the cation exchange resin. Thereby, the silane coupling agent can be concentrated and recovered. There is also sodium hydroxide that is not adsorbed by the cation exchange resin, and such sodium hydroxide is recovered as it is.

  The concentration of the strongly basic solution used in the desorption step in the recycling method B is preferably 0.01 to 5.0N, and more preferably 0.1 to 1.0N. When the concentration of the strongly basic solution is less than 0.01 N, the amount of the strongly basic solution necessary for desorption increases. When the concentration of the strongly basic solution is higher than 5.0N, the deterioration of the cation exchange resin is increased. The amount of the strongly basic solution is preferably 1 to 10 times the cation exchange resin volume. In this way, the silane coupling agent is concentrated, and a mixed solution of the silane coupling agent and the strongly basic solution is recovered.

  As shown in the example shown in FIG. 3, the recycling method B of the present invention preferably further includes a silane coupling agent recovery step (step B-3) after the desorption step (step B-2). In the silane coupling agent recovery step in the recycling method B, using an electrodialyzer, the silane coupling agent is separated from the mixed solution of the silane coupling agent and the strongly basic solution obtained in the desorption step, to recover.

  As a specific method of electrodialysis in the recycling method B, an electrodialysis apparatus in which the anode and the cathode are separated by a diaphragm is used, and the mixed solution obtained in the desorption process is supplied to the anode side. It is preferable. Here, FIG. 4 is a diagram schematically showing an example of electrodialysis in the silane coupling agent recovery step when sodium hydroxide is used as the strong base in the desorption step of the recycling method B of the present invention. FIG. 4 shows an example in which an electrodialysis apparatus including an electrolytic cell 11 including an anode 12 and a cathode 13 and separated into two tanks by a diaphragm 14 is used. Of the two tanks partitioned by the diaphragm 14, the side having the anode 12 is referred to as an anode tank 15, and the side having the cathode 13 is referred to as a cathode tank 16.

  Water is supplied to the cathode tank 16 and a mixed solution of the recovered silane coupling agent and sodium hydroxide is supplied to the anode tank 15. As the diaphragm 14, an unglazed plate, a membrane filter, a UF membrane, or the like can be suitably used.

In the mixed solution of the silane coupling agent obtained in the desorption step and the strongly basic solution, for example, when the strong base is sodium hydroxide, Na ⁺ ions, silane coupling agents (positive as described above, H ⁺ ions, OH ⁻ ions are present. In the cathode chamber 16, H ⁺ ions and OH ⁻ ions are present.

When a voltage is applied between the anode 12 and the cathode 13, cations are attracted to the cathode 13 and anions are attracted to the anode. That is, Na ⁺ ions, H ⁺ ions, and a silane coupling agent are attracted to the cathode 13 side. Na ⁺ ions and H ⁺ ions are monoatomic ions and can easily pass through the diaphragm 14. In contrast, silane coupling agents are positively charged, for example, 3-aminopropyltriethoxysilane has a molecular weight of 221 and 3- (2-aminoethyl) aminopropyltrimethoxysilane has a molecular weight of 222. Since the molecular size is usually large, the membrane 14 cannot pass through.

Therefore, on the cathode 13 side, sodium hydroxide is generated and hydrogen is generated by the reaction of 2Na + 2H ₂ O + 2e ⁻ → 2NaOH + H ₂ . As a result, sodium hydroxide is recovered in the cathode chamber 16. The strongly basic solution containing the collected sodium hydroxide and the like can be reused in the above desorption process.

OH ⁻ ions are attracted to the anode 12 side, and oxygen is generated by the reaction of 4OH ⁻ → O ₂ + 2H ₂ O + 4e ⁻ . Further, since the silane coupling agent cannot pass through the diaphragm 14, it is collected in the anode tank 15. The recovered silane coupling agent can be reused in, for example, a liquid crystal panel manufacturing process or a semiconductor manufacturing process.

  In the recycling method B of the present invention, the ion exchanger after removing the mixed solution of the silane coupling agent and the strongly basic solution in the desorption step (step B-2) as in the example shown in FIG. Further, it is preferable to further provide the regeneration step (step B-4). In the regeneration step in the recycling method B, the ion exchanger after desorption of the silane coupling agent is brought into contact with a strongly acidic solution to regenerate the ion exchanger. In the regeneration step, the strong acid in the strongly acidic solution for contacting the cation exchange resin adsorbed with the cation derived from the strongly basic solution and desorbing the cation from the cation exchange resin includes, for example, hydrochloric acid, sulfuric acid, nitric acid, etc. Can be used.

In the desorption step, for example, when sodium hydroxide is used as the strong base, as described above, Na ⁺ ions and the cation exchange resin are bonded so as to form a salt. Since the carboxylic acid group has weak acidity, for example, when it comes into contact with hydrochloric acid, Na ⁺ ions and H ⁺ ions are substituted as shown below, and are easily regenerated by an acidic solution.

Accompanying this, Na ⁺ ions can be rapidly desorbed from the resin and recovered. The recovered Na ⁺ ions produce sodium hydroxide. Therefore, a mixed solution of a strongly acidic solution containing hydrochloric acid and the like that has passed without being adsorbed by the cation exchange resin and a strongly basic solution containing sodium hydroxide or the like is recovered.

  As a density | concentration of the strongly acidic solution used for reproduction | regeneration of a cation exchange resin, it is preferable that it is 0.01-5.0N, and it is more preferable that it is 0.1-1.0N. When the concentration of the strongly acidic solution is less than 0.01 N, the amount of the strongly basic solution necessary for desorption increases. When the concentration of the strongly acidic solution is greater than 5.0N, the cation exchange resin is greatly deteriorated. The amount of the strongly acidic solution is preferably 1 to 10 times the volume of the cation exchange resin.

  By the regeneration step, the cation exchange resin becomes H-form, and the silane coupling agent can be adsorbed again in the operation of the adsorption step.

  The amount of the strongly basic solution used for desorption of the silane coupling agent from the ion exchanger and the amount of the strongly acidic solution used for regeneration of the ion exchanger are the same as the waste liquid that can be treated by one ion exchange treatment. The amount of the resin can be regenerated efficiently and the silane coupling agent can be recovered and concentrated.

  As in the example shown in FIG. 3, the recycling method B of the present invention preferably further includes an acid / base recovery step (step B-5) after the regeneration step (step B-4). In the acid / base recovery step in the recycling method B, a strong basic solution and a strong acidic solution are respectively obtained from the mixed solution of the strong basic solution and the strong acidic solution obtained in the regeneration step using an electrodialyzer. Separate and collect.

  As a specific method of electrodialysis in the recycling method B, an electrolysis apparatus in which a gap between an anode and a cathode is separated into an anode tank, one or more intermediate tanks and a cathode tank with a plurality of diaphragms is used. It is preferable that water is supplied to the cathode tank and the mixed solution obtained in the regeneration step is supplied to the intermediate tank. Here, FIG. 5 is a diagram schematically showing an example of electrodialysis in the acid / base recovery step when sodium hydroxide is used as the strong base in the desorption step of the recycling method B of the present invention. FIG. 5 shows an example in which an electrodialysis apparatus including an electrolytic cell 21 including an anode 22 and a cathode 23 and separated into three tanks by diaphragms 24 and 25 is shown. Of the three tanks partitioned by the diaphragms 24 and 25, the side with the anode 22 is called the anode tank 26, the side with the cathode 23 is called the cathode tank 27, and the tank between the anode tank 26 and the cathode tank 27 is called the intermediate tank 28. I will decide.

  Water is supplied to the intermediate tank 28 and the anode tank 26, and a mixed solution of a silane coupling agent and hydrochloric acid is supplied to the cathode tank 27. As the diaphragm, a cation exchange membrane can be suitably used as the diaphragm 24 between the anode tank 26 and the intermediate tank 28. As the diaphragm 25 between the cathode tank 27 and the intermediate tank 28, a membrane filter, a UF film, an unglazed plate, or the like is preferably used, and a membrane filter, a UF film, an unglazed plate, or the like can also be suitably used.

In the mixed solution of the strongly basic solution and the strongly acidic solution obtained in the regeneration step, for example, when the strong base is sodium hydroxide and the strong acid is hydrochloric acid, Na ⁺ ions, OH ⁻ ions, H ⁺ Ions and Cl ^- ions are present. H ⁺ ions and OH ⁻ ions are present in the anode cell 26 and the cathode cell 27. When a voltage is applied between the anode 22 and the cathode 23, Na ⁺ ions and H ⁺ ions in the mixed solution in the intermediate tank 28 are attracted to the cathode 23 side. Na ⁺ ions and H ⁺ ions pass through the diaphragm 25 between the intermediate cell 28 and the cathode cell 27, and sodium hydroxide is generated by the reaction of 2Na ⁺ + 2H ₂ O + 2e ⁻ → 2NaOH + H ₂ at the cathode to generate hydrogen. To do. As a result, sodium hydroxide is recovered in the cathode chamber 27.

Cl ⁻ ions and OH ⁻ ions in the mixed solution of NaCl and hydrochloric acid in the intermediate tank 28 are attracted to the anode 26 side, but the cation exchange membrane between the intermediate tank 28 and the anode tank has a negatively charged Cl ^- impervious to ion. Therefore, Cl ⁻ ions remain in the intermediate tank 28. Thus, the anode cell Cl ^- ions not be moved, toxic Cl at the anode ^- gas is not generated.

In the anode tank 26, OH ⁻ ions in the solution generate oxygen due to a reaction of 4OH ⁻ → O ₂ + 2H ₂ O + 4e ⁻ on the anode 22. H ⁺ ions are attracted to the cathode 23 side and move to the intermediate tank 28 when a membrane filter, UF film, unglazed plate, or the like is used as the diaphragm 25 between the intermediate tank 28 and the cathode tank 27. Since Cl ⁻ ions remain in the intermediate tank 28, hydrochloric acid is recovered in the intermediate tank 28. Some H ⁺ ions further move to the cathode 23 side, and hydrogen is generated.

  Thus, a strongly acidic solution is recovered in the intermediate tank 28 and a strongly basic solution is recovered in the cathode tank 27. In the anode tank 26, water is recovered as it is. The recovered strongly acidic solution can be used again in the above regeneration step. The recovered strongly basic solution can be used again in the above desorption process.

  Thus, according to the present invention, a solvent (preferably pure water) is recovered from a solution containing a silane coupling agent without using a lot of energy and without generating waste, and further, silane The coupling agent can be recovered.

  Hereinafter, although an example of an experiment is given and the present invention is explained in detail, the present invention is not limited to these.

<Experimental example>
FIG. 6 is a graph showing the adsorption behavior of the silane coupling agent to the cation exchange resin, where the vertical axis is the silane coupling agent concentration (mg / L) and the horizontal axis is the liquid flow rate (L / L-resin). is there. A chromatography column having a diameter of 20 mm and a length of 300 mm was filled with 50 mL of a weakly acidic cation exchange resin (Amberlite IRC76, manufactured by Rohm and Haas), and a 0.1 wt% silane coupling agent solution was passed therethrough. The concentration of the silane coupling agent in the passing liquid was 0.8 mg / L. When 7500 mL of the silane coupling agent solution was passed through, ie, 150 (L / L-resin), the silane coupling agent began to leak into the passing solution.

  Next, the operation of the desorption process was performed on the resin on which the silane coupling agent was adsorbed. 250 mL, 5 (L / L-resin) of 1.0 mol / L aqueous sodium hydroxide solution was passed through the cation exchange resin adsorbed with the silane coupling agent. The recovered 250 mL of liquid contained 2.8% by weight of the silane coupling agent, and the recovery rate of the silane coupling agent was 93%.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  ADVANTAGE OF THE INVENTION According to this invention, the discard amount of the silane coupling agent waste liquid discharged | emitted from a liquid crystal panel and a semiconductor manufacturing process can be suppressed as much as possible, and resources can be utilized effectively. Furthermore, pure water and a silane coupling agent can be collected and used in a liquid crystal panel manufacturing process and / or a semiconductor device manufacturing process.

  DESCRIPTION OF SYMBOLS 1 Electrodialysis tank, 2 Anode, 3 Cathode, 4 Diaphragm, 5 Diaphragm, 6 Anode tank, 7 Cathode tank, 8 Intermediate tank, 11 Electrodialysis tank, 12 Anode, 13 Cathode, 14 Diaphragm, 15 Anode tank, 16 Cathode tank , 21 Electrodialysis tank, 22 Anode, 23 Cathode, 24 Diaphragm, 25 Diaphragm, 26 Anode tank, 27 Cathode tank, 28 Intermediate tank.

Claims (13)

  A method for recycling a solution containing a silane coupling agent, comprising an adsorption step in which a solution containing a silane coupling agent is brought into contact with an ion exchanger and the silane coupling agent is adsorbed on the ion exchanger.   The recycling method according to claim 1, wherein the ion exchanger contains an ion exchanger having at least one of carboxylic acid and sulfonic acid as an exchange group.   The desorption regeneration process of making the ion exchanger which adsorb | sucked the silane coupling agent contact with a strong acidic solution, desorbing a silane coupling agent from an ion exchanger, and also reproduce | regenerating an ion exchanger is included. Recycling method.   The recycling method according to claim 1 or 2, comprising a desorption step of bringing the ion exchanger adsorbed with the silane coupling agent into contact with a strongly basic solution and desorbing the silane coupling agent from the ion exchanger.   The recycling method according to claim 4, further comprising a regeneration step of regenerating the ion exchanger by bringing the ion exchanger after desorption of the silane coupling agent into contact with a strongly acidic solution.   The method further comprises a silane coupling agent recovery step of recovering the silane coupling agent from a mixed solution of the silane coupling agent and the strongly acidic solution obtained in the desorption regeneration step using an electrodialysis apparatus. The recycling method described.   Using an electrodialysis apparatus in which the anode and cathode are separated into an anode tank, one or more intermediate tanks and a cathode tank with a plurality of diaphragms, water is supplied to the anode tank and the intermediate tank, and the cathode tank is subjected to the desorption and regeneration step. The recycling method according to claim 6, wherein the obtained mixed solution is supplied.   The method further comprises a silane coupling agent recovery step of separating and recovering the silane coupling agent from the mixed solution of the silane coupling agent and the strongly basic solution obtained in the desorption step using an electrodialyzer. Item 6. The recycling method according to Item 4 or 5.   The recycling method according to claim 8, wherein the mixed solution obtained in the desorption step is supplied to the anode side using an electrodialysis apparatus in which the anode and the cathode are separated by a diaphragm.   The method further includes an acid / base recovery step of separating and recovering the strong basic solution and the strong acidic solution from the mixed solution of the strong basic solution and the strong acidic solution obtained in the regeneration step using an electrodialyzer. The recycling method according to claim 4, 5, 8, or 9.   Using an electrodialysis apparatus in which the anode and cathode are separated into an anode tank, one or more intermediate tanks and a cathode tank with a plurality of diaphragms, water is supplied to the anode tank and the cathode tank, and the intermediate tank is subjected to the regeneration step. The recycling method according to claim 10, wherein the obtained mixed solution is supplied.   The recycling method according to any one of claims 1 to 11, wherein the silane coupling agent is an amino-based silane coupling agent.   The manufacturing method of the silane coupling agent containing the recycling method of the solution containing the silane coupling agent in any one of Claims 1-12.

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